Display apparatus

Abstract

The present invention simplifies a manufacturing process of a high-definition display apparatus. Provided is a display apparatus having a color conversion layer and a light-emitting device. In the display apparatus: the light-emitting device has a first electrode, a second electrode, a light-emitting layer, and a first layer; the light-emitting layer is positioned between the first electrode and the second electrode; the first layer is positioned between the light-emitting layer and the second electrode; the first layer has a first organic compound, a second organic compound, and one or both of a metal and a metal compound; and the absorption spectrum of a first mixed film having the first organic compound, the second organic compound, and one or both of the metal and the metal compound has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of a second mixed film having either one of the first organic compound and the second organic compound and one or both of the metal and the metal compound, and having a film thickness that differs from the film thickness of the first mixed film by 10% or less.

Description

display device

[0001] One aspect of the present invention relates to light-emitting devices, light-emitting apparatuses, display devices, electronic devices, lighting apparatuses, and electronic devices. However, one aspect of the present invention is not limited to the above-mentioned technical field. One aspect of the present invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, one aspect of the technical field of one aspect of the present invention disclosed herein is, for example, a semiconductor device, a display device, a liquid crystal display device, a light-emitting apparatus, a lighting apparatus, a power storage device, a memory device, an imaging device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), a method for driving them, or a method for manufacturing them.

[0002] Display devices have been developed for a variety of applications in recent years. For example, large-scale display devices include home television systems (also called televisions or television receivers), digital signage (electronic billboards), and PID (Public Information Display), while small-scale display devices such as smartphones and tablet terminals equipped with touch panels are being developed.

[0003] At the same time, there is a demand for higher resolution in display devices. Devices that require high-resolution display devices include those for virtual reality (VR), augmented reality (AR), substitute reality (SR), and mixed reality (MR), and development is actively underway for these applications.

[0004] As display elements used in display devices, the development of light-emitting devices (also called light-emitting elements) is progressing rapidly. Light-emitting devices that utilize the electroluminescence (EL) phenomenon (also called EL devices or EL elements), especially organic EL devices that mainly use organic compounds, are suitable for display devices because they have features such as being easy to make thin and light, being able to respond quickly to input signals, and being able to be driven using a DC constant voltage power supply.

[0005] To obtain higher-resolution display devices using organic EL devices, research is being conducted on patterning organic compound layers using photolithography as an alternative to deposition methods using metal masks. By using photolithography, it is possible to obtain high-resolution display devices with organic compound layers spaced several micrometers apart (see, for example, Patent Document 1).

[0006] Furthermore, display devices using quantum dots (QDs) as color conversion layers are beginning to become widespread. Quantum dots are semiconductor nanoparticles with a diameter of only a few nanometers. Due to the quantum size effect, the band gap can be adjusted by the size of the particles, allowing incident light to be converted into light of different wavelengths depending on the particle size. Specifically, as the particle size decreases, it becomes possible to convert light into shorter wavelengths, and as the particle size increases, it becomes possible to convert light into longer wavelengths. Displays using quantum dots as color conversion layers utilize this property to convert light of the same wavelength into light of different colors for each sub-pixel by changing the particle size for each sub-pixel, thereby enabling full-color display (for example, Patent Document 2).

[0007] Special Publication No. 2018-521459 Publication Patent No. 6159302

[0008] Conventionally, organic electroluminescent (OLED) devices, which have an organic compound layer (also called an EL layer) between the anode and cathode, are known to be affected in their initial characteristics and reliability when the cathode and organic compound layer are exposed to atmospheric components such as water and oxygen. Therefore, it has been common practice to fabricate OLED devices in an inert gas atmosphere or a near-vacuum atmosphere. On the other hand, during the fabrication of OLED devices, in the process of processing the organic compound layer using lithography methods such as photolithography (hereinafter, this process may be referred to as the lithography process), the organic compound layer may be exposed to atmospheric components such as water and oxygen, as well as water and chemicals used in the photolithography process. Therefore, there is a need to develop OLED devices with an organic compound layer that is highly resistant to such environments.

[0009] Furthermore, as mentioned above, when manufacturing full-color display devices, including organic EL devices that use lithography methods such as photolithography to process the organic compound layer, it is necessary to create separate organic compound layers for each color, which increases the number of manufacturing steps. On the other hand, in high-resolution full-color display devices, including organic EL devices manufactured using conventional methods, leakage current occurs between adjacent subpixels, resulting in a decrease in the light emission and display quality of adjacent subpixels. Therefore, it is difficult to achieve both high resolution and high display quality in display devices.

[0010] Therefore, one aspect of the present invention aims to simplify the manufacturing process of a high-definition display device. Alternatively, one aspect of the present invention aims to improve the display quality of a display device. Alternatively, one aspect of the present invention aims to provide a novel display device.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other problems from the description in the specification, drawings, and claims.

[0012] One aspect of the present invention is a display device having a color conversion layer and a light-emitting device, wherein the light-emitting device has a first electrode, a second electrode, a light-emitting layer and a first layer, the light-emitting layer is located between the first electrode and the second electrode, the first layer is located between the light-emitting layer and the second electrode, the first layer has a first organic compound, a second organic compound and either one or both a metal and a metal compound, and the absorption spectrum of a first mixed film having a first organic compound, a second organic compound and either one or both a metal and a metal compound has a wavelength region in which the absorption intensity is greater than that of a second mixed film having either one of the first organic compound and the second organic compound and either one or both a metal and a metal compound, and having a film thickness difference of 10% or less from the film thickness of the first mixed film.

[0013] Furthermore, one aspect of the present invention is a display device having a color conversion layer and a light-emitting device, wherein the light-emitting device has a first electrode, a second electrode, a light-emitting layer and a first layer, the light-emitting layer is located between the first electrode and the second electrode, the first layer is located between the light-emitting layer and the second electrode, the first layer has a first organic compound, a second organic compound and either one or both a metal and a metal compound, and the absorption of a first mixed film having the first organic compound, the second organic compound and either one or both a metal and a metal compound The display device has a spectrum in which the absorption intensity is greater in a wavelength region than the absorption spectrum of a third mixed film having a thickness difference of 10% or less from the thickness of the first mixed film, and the absorption spectrum of the first mixed film having a wavelength region in which the absorption intensity is greater in a wavelength region than the absorption spectrum of a fourth mixed film having a thickness difference of 10% or less from the thickness of the first mixed film, and the absorption spectrum of the first mixed film having a wavelength region in which the absorption intensity is greater in a wavelength region than the absorption spectrum of a fourth mixed film having a thickness difference of 10% or less from the thickness of the first mixed film.

[0014] Furthermore, one aspect of the present invention is a display device having a color conversion layer and a light-emitting device, wherein the light-emitting device has a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer, the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, the first layer is located between the first light-emitting layer and the second light-emitting layer, the first layer has a first organic compound, a second organic compound, and either or both a metal and a metal compound, and the absorption spectrum of a first mixed film having a first organic compound, a second organic compound, and either or both a metal and a metal compound has a wavelength region in which the absorption intensity is greater than that of a second mixed film having either one of the first organic compound and the second organic compound, and either or both a metal and a metal compound, and having a film thickness difference of 10% or less from the film thickness of the first mixed film.

[0015] Furthermore, one aspect of the present invention is a display device having a color conversion layer and a light-emitting device, wherein the light-emitting device has a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer, the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, the first layer is located between the first light-emitting layer and the second light-emitting layer, the first layer has a first organic compound, a second organic compound, and either or both a metal and a metal compound, and the first organic compound, the second organic compound, and either or both a metal and a metal compound The display device has a first mixed film whose absorption spectrum has a wavelength region with greater absorption intensity than the absorption spectrum of a third mixed film which contains a first organic compound and either a metal or a metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film has a wavelength region with greater absorption intensity than the absorption spectrum of a fourth mixed film which contains a second organic compound and either a metal or a metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film.

[0016] One aspect of the present invention is a display device comprising a color conversion layer and a light-emitting device, wherein the light-emitting device comprises a first electrode, a second electrode, a light-emitting layer and a first layer, the light-emitting layer is located between the first electrode and the second electrode, the first layer is located between the light-emitting layer and the second electrode, and the first layer comprises a first organic compound, a second organic compound and either a metal and a metal compound or both, wherein the first mixed film comprises a first organic compound, a second organic compound and either a metal and a metal compound or both, the second mixed film comprises either the first organic compound and the second organic compound and either a metal and a metal compound or both, and has a film thickness such that the difference in film thickness from the first mixed film is within 10%, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the second mixed film.

[0017] Furthermore, one aspect of the present invention is a display device having a color conversion layer and a light-emitting device, the light-emitting device having a first electrode, a second electrode, a light-emitting layer and a first layer, the light-emitting layer being located between the first electrode and the second electrode, the first layer being located between the light-emitting layer and the second electrode, and the first layer having a first organic compound, a second organic compound and either one or both of a metal and a metal compound, the first mixed film having a first organic compound, a second organic compound and either one or both of a metal and a metal compound, and the third mixed film having a first organic A display device comprising a compound and either a metal or a metal compound, or both, and having a film thickness such that the difference in film thickness from the first mixed film is within 10%, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the third mixed film; and a fourth mixed film comprising a second organic compound and either a metal or a metal compound, or both, and having a film thickness such that the difference in film thickness from the first mixed film is within 10%, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film.

[0018] Furthermore, one aspect of the present invention is a display device comprising a color conversion layer and a light-emitting device, wherein the light-emitting device comprises a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer, the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, the first layer is located between the first light-emitting layer and the second light-emitting layer, and the first layer comprises a first organic compound, a second organic compound, and either a metal or a metal compound, wherein the first mixed film comprises a first organic compound, a second organic compound, and either a metal or a metal compound, and the second mixed film comprises either one of the first organic compound and the second organic compound, and either a metal or a metal compound, and has a film thickness such that the difference in film thickness from the first mixed film is within 10%, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the second mixed film.

[0019] Furthermore, one aspect of the present invention is a display device having a color conversion layer and a light-emitting device, the light-emitting device having a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer, the first light-emitting layer and the second light-emitting layer being located between the first electrode and the second electrode, the first layer being located between the first light-emitting layer and the second light-emitting layer, the first layer having a first organic compound, a second organic compound, and either one or both of a metal and a metal compound, the first mixed film having a first organic compound, a second organic compound, and either one or both of a metal and a metal compound, The third mixed film contains a first organic compound and either a metal or a metal compound, or both, and has a film thickness that is no more than 10% different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the third mixed film. The fourth mixed film contains a second organic compound and either a metal or a metal compound, or both, and has a film thickness that is no more than 10% different from that of the first mixed film, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film.

[0020] Furthermore, one aspect of the present invention includes a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer, wherein the organic compound layer is located between the first electrode and the second electrode, the second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall, the color conversion layer is located above the second electrode and the partition wall, the partition wall has an inverse tapered shape in cross-section and is conductive, the organic compound layer includes a light-emitting layer and a first layer, the light-emitting layer is located between the first electrode and the second electrode, the first layer is located between the light-emitting layer and the second electrode, and the first layer is a first organic compound and The present invention relates to a display device comprising a second organic compound and either a metal or a metal compound, wherein the first mixed film comprises the first organic compound, the second organic compound, and either a metal or a metal compound, and the second mixed film comprises either the first organic compound or the second organic compound, and either a metal or a metal compound, and has a film thickness such that the difference between it and the film thickness of the first mixed film is 10% or less, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the second mixed film.

[0021] Furthermore, one aspect of the present invention is a display device comprising a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer, wherein the organic compound layer is located between the first electrode and the second electrode, the second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall, the color conversion layer is located above the second electrode and the partition wall, the partition wall has an inverse tapered shape in cross-sectional view and is conductive, the organic compound layer comprises a light-emitting layer and a first layer, the light-emitting layer is located between the first electrode and the second electrode, the first layer is located between the light-emitting layer and the second electrode, and the first layer comprises a first organic compound, a second organic compound, and either one or both of a metal and a metal compound, the first mixture The display device comprises a film having a first organic compound, a second organic compound, and either a metal or a metal compound, or both; a third mixed film having the first organic compound, and either a metal or a metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film having a wavelength region with greater absorption intensity than the absorption spectrum of the third mixed film; and a fourth mixed film having the second organic compound, and either a metal or a metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film having a wavelength region with greater absorption intensity than the absorption spectrum of the fourth mixed film.

[0022] Furthermore, one aspect of the present invention comprises a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer, wherein the organic compound layer is located between the first electrode and the second electrode, the second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall, the color conversion layer is located above the second electrode and the partition wall, the partition wall has an inverse tapered shape in cross-sectional view and is conductive, the organic compound layer comprises a first light-emitting layer, a first layer, and a second light-emitting layer, the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, the first layer is located between the first light-emitting layer and the second light-emitting layer, and The layer is a display device having a first organic compound, a second organic compound, and either a metal or a metal compound, wherein the first mixed film has the first organic compound, the second organic compound, and either a metal or a metal compound, and the second mixed film has either the first organic compound or the second organic compound, and either a metal or a metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the second mixed film.

[0023] Furthermore, one aspect of the present invention includes a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer, wherein the organic compound layer is located between the first electrode and the second electrode, the second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall, the color conversion layer is located above the second electrode and the partition wall, the partition wall has an inverse tapered shape in cross-section and is conductive, the organic compound layer includes a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer, the first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode, the first layer is located between the first light-emitting layer and the second light-emitting layer, and the first layer includes a first organic compound, a second organic compound, and either one or both of a metal and a metal compound. A display device having the following characteristics: The first mixed film comprises a first organic compound, a second organic compound, and either or both a metal and a metal compound; the third mixed film comprises a first organic compound, and either or both a metal and a metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the third mixed film; the fourth mixed film comprises a second organic compound, and either or both a metal and a metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the fourth mixed film.

[0024] Furthermore, in one aspect of the present invention, the display device having the above configuration is a display device in which the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the second mixed film, in a region with wavelengths longer than the absorption edge on the long-wavelength side of the absorption spectrum of the organic compound film having the second mixed film.

[0025] Furthermore, in one aspect of the present invention, the display device having the above configurations is a display device in which the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the third mixed film in a region with wavelengths longer than the absorption edge on the long-wavelength side of the absorption spectrum of the film having the first organic compound, and the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film in a region with wavelengths longer than the absorption edge on the long-wavelength side of the absorption spectrum of the film having the second organic compound.

[0026] Furthermore, one aspect of the present invention is a display device having the above configuration, wherein either the metal or the metal compound, or both, are metallic elements belonging to any of the groups from Group 3 to Group 14 of the periodic table.

[0027] Furthermore, one aspect of the present invention is a display device having the above configuration, wherein either the metal or the metal compound, or both, are metallic elements belonging to Group 3, Group 11, or Group 13 of the periodic table.

[0028] Furthermore, one aspect of the present invention is a display device having the above configuration, wherein the display device has a second layer, the second layer is located between the first layer and the second electrode, and the second layer has a third organic compound and a fourth organic compound, the third organic compound is an organic compound or aromatic amine having a π-electron-excess heteroaromatic ring, and the fourth organic compound has at least one halogen group and a cyano group.

[0029] Furthermore, one aspect of the present invention is a display device having the above configuration, wherein the LUMO level of the first organic compound is higher than the LUMO level of the second organic compound.

[0030] Furthermore, one aspect of the present invention is a display device having the above configuration, wherein the HOMO level of the first organic compound is higher than the HOMO level of the second organic compound.

[0031] Furthermore, in one aspect of the present invention, the display device having the above configuration is a display device in which the first organic compound and the second organic compound each have a heteroaromatic ring.

[0032] Furthermore, in one aspect of the present invention, the display device having the above configuration is a display device in which the heteroaromatic ring of the first organic compound and the heteroaromatic ring of the second organic compound each independently contain at least one of the following: a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, and a triazole ring.

[0033] Furthermore, in one aspect of the present invention, the display device having the above configuration is a display device in which the first organic compound has an electron-donating group.

[0034] Furthermore, one aspect of the present invention is a display device having the above configuration, wherein the electron-donating group is at least one of alkyl groups, alkoxy groups, aryloxy groups, alkylamino groups, arylamino groups, and heterocyclic amino groups.

[0035] According to one aspect of the present invention, leakage current can be suppressed between subpixels, and color mixing between subpixels can be suppressed, thereby enabling the manufacture of a display device with high display quality. Alternatively, according to one aspect of the present invention, even if the organic compound layers of each light-emitting device are identical, the manufacturing process of a high-definition display device capable of full-color display can be simplified. Furthermore, according to one aspect of the present invention, a display device that is high-definition and consumes little power can be realized. Alternatively, according to one aspect of the present invention, a novel display device can be provided.

[0036] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims.

[0037] Figure 1A is a top view illustrating the configuration of a display device according to an embodiment, and Figure 1B is a cross-sectional view illustrating the configuration of a display device according to an embodiment. Figures 2A, 2B, and 2C are cross-sectional views illustrating the configuration of a display device according to an embodiment. Figures 3A and 3B are cross-sectional views illustrating the configuration of a display device according to an embodiment. Figures 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, and 4I are cross-sectional views illustrating the configuration of a display device according to an embodiment. Figures 5A and 5B are diagrams illustrating the configuration of a light-emitting device according to an embodiment. Figure 6 is a diagram illustrating the configuration of a light-emitting device according to an embodiment. Figures 7A, 7B, and 7C are the analysis results of the spin density distribution in the ground state of a composite material. Figure 8 is the analysis results of the spin density distribution in the ground state of a composite material. Figures 9A and 9B are the analysis results of the electrostatic potential map in the ground state of an organic compound. Figures 10A, 10B, and 10C are the analysis results of the electrostatic potential map in the ground state of a composite material. Figure 11 shows the analysis results of the electrostatic potential map in the ground state of the composite material. Figures 12A, 12B, 12C, and 12D are diagrams illustrating the configuration of a light-emitting device according to an embodiment. Figures 13A, 13B, 13C, and 13D are cross-sectional views illustrating the configuration of a display device according to an embodiment. Figures 14A, 14B, 14C, and 14D are cross-sectional views showing an example of a method for manufacturing a display device. Figures 15A, 15B, and 15C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 16A, 16B, 16C, and 16D are cross-sectional views showing an example of a method for manufacturing a display device. Figures 17A, 17B, and 17C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 18A, 18B, 18C, 18D, 18E, and 18F are cross-sectional views showing an example of a method for manufacturing a display device. Figures 19A and 19B are perspective views showing an example of a display device. Figures 20A and 20B are cross-sectional views showing an example of a display device. Figures 21A and 21B show an example of an electronic device. Figures 22A, 22B, 22C, 22D, 22E, and 22F show an example of an electronic device. Figures 23A and 23B illustrate the configuration of a light-emitting device according to an embodiment.Figure 24 is a diagram illustrating the configuration of a light-emitting device according to an embodiment. Figures 25A and 25B show the absorption spectra of mixed film 1, mixed film 2, mixed film 3, mixed film 4, and single film 3. Figures 26A and 26B show the absorption spectra of single film 1 and single film 2. Figures 27A and 27B show the absorption spectra of mixed film 5, mixed film 6, mixed film 7, and single film 4. Figures 28A and 28B show the absorption spectra of mixed film 8, mixed film 2, mixed film 9, mixed film 10, and single film 3. Figures 29A and 29B show the absorption spectra of single film 1 and single film 5. Figures 30A and 30B show the absorption spectra of mixed film 11, mixed film 12, mixed film 13, and single film 6. Figures 31A, 31B, and 31C are LDI-MS spectra of co-evaporated films containing Hid2Phen, 6,6'(P-Bqn)2BPy, and In. Figure 32 is a cross-sectional STEM image of analysis sample 1a. Figure 33 is a cross-sectional STEM image of analysis sample 1b. Figure 34 is a cross-sectional STEM image of analysis sample 2a. Figure 35 is a cross-sectional STEM image of analysis sample 2b. Figure 36 shows the results of SIMS analysis of analysis sample 1a and analysis sample 1b. Figure 37 shows the results of SIMS analysis of analysis sample 2a and analysis sample 2b. Figure 38 shows the external quantum efficiency-current density characteristics of analysis device 1a and analysis device 1b. Figure 39 shows the current density-voltage characteristics of analysis device 1a and analysis device 1b. Figure 40 shows the external quantum efficiency-current density characteristics of analysis device 2a and analysis device 2b. Figure 41 shows the current density-voltage characteristics of analytical devices 2a and 2b. Figure 42 shows the brightness-current density characteristics of device 1. Figure 43 shows the brightness-voltage characteristics of device 1. Figure 44 shows the current efficiency-brightness characteristics of device 1. Figure 45 shows the current density-voltage characteristics of device 1. Figure 46 shows the blue index-brightness characteristics of device 1. Figure 47 is the electroluminescence spectrum of device 1. Figure 48 shows the change in brightness with respect to the operating time of device 1.

[0038] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following description, and its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be interpreted as being limited to the contents of the embodiments shown below.

[0039] Please note that the positions, sizes, and ranges of each component shown in the drawings may not represent their actual positions, sizes, and ranges for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0040] Furthermore, the ordinal numbers used in this specification, such as "first," "second," etc., are for convenience only and may not indicate the order of processes or stacking. Therefore, for example, "first" can be replaced with "second" or "third," etc., as appropriate in the explanation. Also, the ordinal numbers described in this specification may not be the same as the ordinal numbers used to specify an aspect of the present invention.

[0041] Furthermore, in this specification and other documents, when describing the structure of the invention using drawings, reference numerals that refer to the same thing may be used in common across different drawings.

[0042] Furthermore, in this specification, the terms "film" and "layer" are interchangeable. For example, the term "conductive layer" may be changed to "conductive film." Or, for example, the term "insulating film" may be changed to "insulating layer."

[0043] In the drawings and other illustrations relating to this specification, arrows indicating the X, Y, and Z directions may be included. In this specification, the "X direction" refers to the direction along the X-axis, and unless explicitly stated, the forward and reverse directions may not be distinguished. The same applies to the "Y direction" and "Z direction." Furthermore, the X, Y, and Z directions are directions that intersect each other. For example, the X, Y, and Z directions are directions that are orthogonal to each other.

[0044] In this specification, the positional relationship of each component may be described using the terms "up" or "down," but the present invention is not limited to such descriptions. For example, when the direction of light extraction is described as "up," a layer formed later in the film deposition sequence may be described as a layer "up" a previously formed layer. Furthermore, the terms "up" or "down" may also be used in correspondence with the top-down relationship in the drawings, without being limited to these examples.

[0045] (Embodiment 1) In this embodiment, a display device according to one aspect of the present invention will be described with reference to Figure 1.

[0046] A display device according to one aspect of the present invention comprises a plurality of light-emitting devices having the same light-emitting material, and a color conversion layer overlapping at least some of the light-emitting devices. By changing the presence or absence of the color conversion layer and the type of color conversion layer used depending on the sub-pixel, the display device can perform full-color display.

[0047] Figure 1A shows a top view of the display device 100. The display device 100 has a display unit on which a plurality of pixels 110 are arranged, and a connection unit 140 on the outside of the display unit. Multiple subpixels are arranged in a matrix on the display unit. In Figure 1A, subpixels in 2 rows and 6 columns are shown, and these constitute a 2 row and 2 column pixel 110. The connection unit 140 can also be called a cathode contact unit.

[0048] The top surface shape of the subpixel shown in Figure 1A corresponds to the top surface shape of the light-emitting region. In this specification, the term "top surface shape" refers to the shape in a plan view, that is, the shape viewed from above.

[0049] Note that the top surface shape of a subpixel is not limited to the shape shown in Figure 1A. Examples of top surface shapes of subpixels include polygons such as triangles, quadrilaterals (including rectangles, rhombuses, and squares), pentagons, polygons with rounded corners, ellipses, or circles.

[0050] Furthermore, the circuit layout constituting the subpixel is not limited to the subpixel range shown in Figure 1A, and the circuit components may be arranged outside of it. In other words, some or all of the transistors in the subpixel 11R shown in Figure 1A may be located outside the range of the subpixel 11R. The transistors in the subpixel 11R may be located within the range of the subpixel 11R shown in Figure 1A, within the range of the subpixel 11G, within the range of the subpixel 11B, or may be arranged across multiple of these ranges.

[0051] In Figure 1A, the aperture ratios (sizes, also known as the size of the light-emitting area) of the sub-pixels 11R, 11G, and 11B are shown to be equal or approximately equal, but one aspect of the present invention is not limited thereto. The aperture ratios of the sub-pixels 11R, 11G, and 11B can be determined as appropriate. The aperture ratios of the sub-pixels 11R, 11G, and 11B may be different, or two or more may be equal or approximately equal.

[0052] A stripe array is applied to the pixel 110 shown in Figure 1A. The pixel 110 shown in Figure 1A is composed of three subpixels: subpixel 11R, subpixel 11G, and subpixel 11B. Subpixels 11R, 11G, and 11B each emit light of a different color. Examples of subpixels 11R, 11G, and 11B include subpixels of three colors: red (R), green (G), and blue (B); and subpixels of three colors: yellow (Y), cyan (C), and magenta (M). Furthermore, the number of subpixel types is not limited to three, but may be four or more. Examples of four subpixels include subpixels of four colors: R, G, B, and white (W); subpixels of four colors: R, G, B, and Y; and subpixels of four colors: R, G, B, and infrared (IR).

[0053] In this specification, the row direction is sometimes referred to as the X direction, the column direction as the Y direction, and the depth direction as the Z direction. Figure 1A shows an example where subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction.

[0054] Figure 1B shows a cross-sectional view between the dashed lines X1 and X2 in Figure 1A. In the cross-sectional view shown in Figure 1B, the top surface of the display device 100 is shown at the bottom.

[0055] The sub-pixel 11R includes a light-emitting device 130 and a color conversion layer 12R that overlaps the light-emitting device 130. The color conversion layer 12R can convert the light emitted by the light-emitting device 130 into red light. As a result, in the sub-pixel 11R, the light emitted by the light-emitting device 130 is extracted as red light to the outside of the display device 100 via the color conversion layer 12R.

[0056] The sub-pixel 11G includes a light-emitting device 130 and a color conversion layer 12G that overlaps the light-emitting device 130. The color conversion layer 12G can convert the light emitted by the light-emitting device 130 into green light. As a result, in the sub-pixel 11G, the light emitted by the light-emitting device 130 is extracted as green light to the outside of the display device 100 via the color conversion layer 12G.

[0057] The sub-pixel 11B includes a light-emitting device 130 and a layer 12B that overlaps the light-emitting device 130. The layer 12B can transmit, scatter, or convert the light emitted by the light-emitting device 130 into blue light. As a result, in the sub-pixel 11B, the light emitted by the light-emitting device 130 is extracted as blue light to the outside of the display device 100 via the layer 12B.

[0058] Here, blue light can be defined as light whose maximum peak wavelength in the emission spectrum is between 400 nm and 480 nm. Green light can be defined as light whose maximum peak wavelength in the emission spectrum is between 480 nm and 580 nm. Red light can be defined as light whose maximum peak wavelength in the emission spectrum is between 580 nm and 700 nm.

[0059] It is preferable to use either a phosphor or quantum dots, or both, as the color conversion layer. In particular, quantum dots have a narrow peak width in their emission spectrum, allowing for emission with good color purity. This can improve the display quality of the display device.

[0060] There are no particular limitations on the materials that constitute quantum dots. Examples include Group 14 elements, Group 15 elements, Group 16 elements, compounds consisting of multiple Group 14 elements, compounds of elements belonging to Groups 4 through 14 and Group 16 elements, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements, compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, compounds of Group 11 elements and Group 17 elements, iron oxides, titanium oxides, chalcogenide spinels, and various semiconductor clusters.

[0061] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, tel Indium sulfide, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, boron arsenide, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, selenide Calcium, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tan oxide Examples include tal, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, compounds of selenium, zinc, and cadmium, compounds of indium, arsenic, and phosphorus, compounds of cadmium, selenium, and sulfur, compounds of cadmium, selenium, and tellurium, compounds of indium, gallium, and arsenic, compounds of indium, gallium, and selenium, compounds of indium, selenium, and sulfur, compounds of copper, indium, and sulfur, and combinations thereof. In addition, so-called alloy-type quantum dots, whose composition is expressed in any ratio, may also be used.

[0062] Quantum dot structures include core type, core-shell type, and core-multishell type. Furthermore, because quantum dots have a high proportion of surface atoms, they are highly reactive and prone to aggregation. Therefore, it is preferable that a protective agent or protective group is attached to the surface of the quantum dots. This attachment of a protective agent or protective group prevents aggregation and improves solubility in solvents. It also reduces reactivity and improves electrical stability.

[0063] As the size of a quantum dot decreases, its band gap increases, so its size is adjusted appropriately to obtain light of a desired wavelength. As the size decreases, the emission of quantum dots shifts towards the blue side, that is, towards higher energy, so by changing the size of the quantum dots, the emission wavelength can be adjusted across the ultraviolet, visible, and infrared spectral wavelength ranges. The size (diameter) of a quantum dot is, for example, 0.5 nm to 20 nm, preferably 1 nm to 10 nm. Furthermore, the narrower the size distribution of quantum dots, the narrower the emission spectrum becomes, and the better the color purity of the emission can be obtained. The shape of the quantum dots is not particularly limited and may be spherical, rod-shaped, disc-shaped, or other shapes. A quantum rod, which is a rod-shaped quantum dot, has the function of exhibiting directional light.

[0064] The color conversion layer can be formed using methods such as droplet ejection (e.g., inkjet), coating, imprint, and various printing methods (screen printing, offset printing). Alternatively, a color conversion film such as a quantum dot film may be used.

[0065] When processing the film that will become the color conversion layer, it is preferable to use photolithography. Photolithography methods include a method in which a resist mask is formed on the thin film to be processed, the thin film is processed by etching or the like, and the resist mask is removed, and a method in which a photosensitive thin film is formed, and then exposed and developed to process the thin film into the desired shape. For example, an island-shaped color conversion layer can be formed by forming a thin film using a material in which quantum dots are mixed with photoresist, and then processing the thin film using photolithography.

[0066] Furthermore, in a display device according to one aspect of the present invention, it is preferable to provide an insulating layer having an opening on a substrate and to provide a color conversion layer within the opening. The insulating layer can be formed using an organic resin film such as acrylic resin, polyamide resin, or epoxy resin, an inorganic insulating film, or an organic polysiloxane. It is particularly preferable to use a photosensitive material and to form the insulating layer so that the side walls of the opening are inclined surfaces with a continuous curvature. By providing the insulating layer, the color conversion layers of each color can be separated, thereby preventing color mixing. Thus, a display device with high display quality can be provided. The insulating layer is also called a partition or embankment because it has the function of separating the color conversion layers of each color.

[0067] However, quantum dots have the drawback of being susceptible to degradation due to the intrusion of impurities such as oxygen. When quantum dots degrade, the light emission intensity of the pixels decreases, and the display quality of the display device deteriorates. Therefore, in display devices that use quantum dots as a color conversion layer, it is necessary to prevent the intrusion of impurities such as oxygen from around the color conversion layer and to prevent the degradation of the quantum dots.

[0068] Therefore, in one embodiment of the present invention, an inorganic film is provided to cover the color conversion layer. This prevents impurities such as oxygen from entering the color conversion layer, thereby providing a display device with high display quality.

[0069] As shown in Figure 1B, the display device 100 has a structure in which unit 30 and unit 31 are bonded together by a resin layer 32. Unit 30 includes a substrate 40, a partition wall 20, a color conversion layer 12R, a color conversion layer 12G, a layer 12B, and an inorganic film 22. Unit 31 includes a light-emitting device 130 and a layer 251 containing a transistor. In Figure 1B, the dashed arrows indicate the direction of light emission.

[0070] In unit 30, the partition wall 20 is an insulating layer located on the substrate 40 and having an opening. The color conversion layer 12R, color conversion layer 12G, and layer 12B each have portions located within the opening of the partition wall 20. In the description of unit 30, "upper" refers to the vertical relationship when the substrate 40 side is considered lower and the color conversion layer 12R, color conversion layer 12G, and layer 12B side are considered upper.

[0071] The inorganic film 22 has portions located on the color conversion layer 12R, the color conversion layer 12G, and layer 12B.

[0072] In other words, the color conversion layer 12R, the color conversion layer 12G, and the layer 12B are each covered with an inorganic film 22. By providing the inorganic film 22 that covers the color conversion layers in this way, it is possible to prevent impurities such as oxygen from entering the color conversion layer 12R, the color conversion layer 12G, and the layer 12B, thereby preventing the color conversion layer 12R, the color conversion layer 12G, and the layer 12B from degrading due to impurities such as oxygen. Therefore, a highly reliable display device can be made.

[0073] An inorganic insulating film is preferred as the inorganic film 22. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxide nitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together. In particular, using a metal nitride film such as silicon nitride or aluminum nitride film is effective in preventing oxygen from entering the color conversion layer because the material itself does not contain oxygen.

[0074] From the viewpoint of suppressing the permeation of oxygen and the like, the thickness of the inorganic film 22 is preferably 10 nm or more, and more preferably 50 nm or more. On the other hand, from the viewpoint of suppressing a decrease in the transmittance of light emitted by the light-emitting device, the thickness of the inorganic film 22 is preferably 1000 nm or less, and more preferably 500 nm or less.

[0075] The substrate 40 can be made of glass, quartz, ceramics, sapphire, resin, metal, alloy, semiconductor, etc. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. Using a flexible material for the substrate 40 can increase the flexibility of the display device. Alternatively, a polarizing plate or the like may be used as the substrate 40. Thus, a variety of materials can be used as the substrate.

[0076] As the substrate 40, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. may be used. Glass with a thickness sufficient to provide flexibility may also be used for the substrate 40.

[0077] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate 40 with high optical isotropy. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0078] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0079] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0080] Furthermore, when a film is used as the substrate 40, the film may absorb water, which could cause changes in shape, such as wrinkles, in the display device. For this reason, it is preferable to use a film with a low water absorption rate for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0081] As the resin layer 32, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0082] In unit 31, light-emitting devices 130 are provided on a layer 251 containing transistors, and a protective layer 131 is provided to cover these light-emitting devices. In addition, an insulating layer 125 and an insulating layer 127 on the insulating layer 125 are provided in the region between adjacent light-emitting devices. In the description of unit 31, "upper" refers to the upper and lower relationship when the layer 251 containing transistors is considered lower and the light-emitting devices 130 are considered upper.

[0083] In Figure 1B, multiple insulating layers 125 and insulating layers 127 are shown, but when the display device 100 is viewed from above, the insulating layers 125 and insulating layers 127 can each be connected as one unit. In other words, the display device 100 can be configured to have, for example, one insulating layer 125 and one insulating layer 127. The display device 100 may also have multiple insulating layers 125 that are separated from each other, or multiple insulating layers 127 that are separated from each other.

[0084] A display device according to one aspect of the present invention may be a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed, a bottom-emission type that emits light toward the substrate on which the light-emitting device is formed, or a dual-emission type that emits light on both sides. In this embodiment, a top-emission type display device will be described as an example.

[0085] The layer 251 containing the transistors can be, for example, a laminated structure in which multiple transistors are provided on a substrate and an insulating layer is provided to cover these transistors. The insulating layer on the transistors may be a single layer or a laminated structure. The layer 251 containing the transistors may have recesses between adjacent light-emitting devices 130. For example, a recess may be provided in the insulating layer located on the outermost surface of the layer 251 containing the transistors. An example of the configuration of the layer 251 containing the transistors will be described later in Embodiment 6.

[0086] Each subpixel's light-emitting device 130 has an organic compound layer 150 and a common layer 151 between the first electrode 101 and the second electrode 102. The common layer 151 can also be considered part of the EL layer in the light-emitting device. In this specification, among the EL layers of the light-emitting device, the layer provided in an island-like manner for each light-emitting device is referred to as the organic compound layer 150, and the layer shared by multiple light-emitting devices is referred to as the common layer 151.

[0087] Multiple organic compound layers 150 are arranged in an island-like manner by processing the organic compound layer using a lithography method. This suppresses the generation of leakage current between subpixels and suppresses color mixing between subpixels, thereby enabling the creation of a display device with high display quality.

[0088] Furthermore, the multiple organic compound layers 150 can all have the same configuration. In other words, the multiple organic compound layers 150 do not need to be made differently for each sub-pixel of each color. As described above, since the display device 100 has a color conversion layer 12R and a color conversion layer 12G that overlap the light-emitting device 130, full-color display is possible even if the multiple organic compound layers 150 all have the same configuration, that is, even if the light-emitting color of the light-emitting device 130 is the same. Therefore, the manufacturing process for a display device with high display quality that can display in full color can be simplified.

[0089] The organic compound layer 150 has a plurality of light-emitting units. In this embodiment, an example is shown in which the organic compound layer 150 has two light-emitting units. Specifically, the organic compound layer 150 has a first light-emitting unit 501, an intermediate layer 160, and a second light-emitting unit 502. It is preferable that the intermediate layer 160 has a layer configuration containing a first organic compound, a second organic compound, and a metal material. Since such a light-emitting device has a low driving voltage, it is preferable to use it in a display device to reduce the power consumption of the display device. Furthermore, it is preferable to use such a light-emitting device in a display device according to one embodiment of the present invention having a color conversion layer, as it is possible to realize a display device that is high-definition and has low power consumption. Details of the light-emitting device will be described later in Embodiments 2 and 3.

[0090] The light-emitting color of the light-emitting device 130 can be infrared, red, green, blue, cyan, magenta, yellow, or white. Furthermore, the color purity can be improved by adding a microcavity structure to the light-emitting device.

[0091] The light-emitting device 130 has a pair of electrodes, with an EL layer (organic compound layer) between the electrodes. Preferably, of the pair of electrodes in the light-emitting device 130, the electrode that extracts light uses a conductive film that transmits visible light, and the electrode that does not extract light uses a conductive film that reflects visible light.

[0092] Of the pair of electrodes in the light-emitting device 130, one electrode functions as the anode and the other electrode functions as the cathode. In the following, the case in which the first electrode 101 functions as the anode and the second electrode 102 functions as the cathode may be used as an example. In this specification, the first electrode 101 may be referred to as the pixel electrode, and the second electrode 102 may be referred to as the common electrode or upper electrode.

[0093] The light-emitting device 130 can be configured to emit multiple colors of light, such as a configuration that emits white light or a configuration that emits blue and green light.

[0094] In a configuration where the light-emitting device 130 emits light of multiple colors, it is preferable that the color conversion layer 12R converts blue and green light into red light and transmits red light. By providing such a color conversion layer 12R in superimposed on the light-emitting device 130, the blue and green light components of the multiple colors of light can be converted into red light components and extracted to the outside of the display device. Therefore, compared to a configuration without the color conversion layer 12R, the efficiency of extracting red light can be increased. Furthermore, it is preferable that the color conversion layer 12R converts light with a shorter wavelength than red (for example, light from blue to orange) into red light and transmits red light. Alternatively, a colored layer that transmits red light may be provided. This can increase the color purity of red.

[0095] Similarly, if the light-emitting device 130 is configured to emit light of multiple colors, it is preferable that the color conversion layer 12G converts blue light into green light and transmits green light. By providing such a color conversion layer 12G in superimposed on the light-emitting device 130, the blue light component of the multiple colors of light can be converted into the green light component and extracted to the outside of the display device. Therefore, the efficiency of extracting green light can be increased compared to a configuration without the color conversion layer 12G. Alternatively, a colored layer that transmits green light may be provided. This can increase the purity of the green color.

[0096] Furthermore, if the light-emitting device 130 is configured to emit light of multiple colors, it is preferable to provide a layer 12B that transmits blue light on top of the light-emitting device 130. This allows the blue light component of the multiple colors of light to be extracted to the outside of the display device. Alternatively, a colored layer that transmits blue light may be provided. This can improve the purity of the blue color.

[0097] Furthermore, by applying a microcavity structure, light-emitting devices configured to emit multiple colors of light may also emit light with a specific wavelength, such as red, green, or blue, being amplified.

[0098] For example, by applying a configuration to the light-emitting device 130 that emits multiple colors of light, and by applying a microcavity structure, red light can be obtained from the light-emitting device 130 in the sub-pixel 11R, green light can be obtained from the light-emitting device 130 in the sub-pixel 11G, and blue light can be obtained from the light-emitting device 130 in the sub-pixel 11B.

[0099] Here, by applying a microcavity structure, it is possible to intensify and extract light of a desired wavelength in the forward direction, but the light extracted from an oblique direction will contain components of multiple colors.

[0100] Therefore, even in a display device to which a microcavity structure is applied, providing color conversion layers 12R and 12G is preferable because it can improve the efficiency of extracting light of the desired color.

[0101] Furthermore, the light-emitting device 130 can be configured to emit, for example, blue light.

[0102] In the case where the light-emitting device 130 emits blue light, it is preferable that the color conversion layer 12R converts the blue light into red light and transmits the red light. By providing such a color conversion layer 12R on top of the light-emitting device 130, the blue light emitted by the light-emitting device 130 can be converted into red light and extracted to the outside of the display device.

[0103] Similarly, if the light-emitting device 130 is configured to emit blue light, it is preferable that the color conversion layer 12G converts the blue light into green light and transmits the green light. By providing such a color conversion layer 12G in superimposed on the light-emitting device 130, the blue light emitted by the light-emitting device 130 can be converted into green light and extracted to the outside of the display device.

[0104] In other words, even if all of the light-emitting devices 130 are configured to emit blue light, a full-color display device can be realized.

[0105] Furthermore, even when the light-emitting device 130 is configured to emit blue light, a microcavity structure may be applied to enhance the blue light emitted by the light-emitting device. Alternatively, a microcavity structure may not be applied.

[0106] Furthermore, the light-emitting device 130 may be configured to emit light with a shorter wavelength than blue light; for example, it may be configured to emit purple light or ultraviolet light.

[0107] Here, examples of light with wavelengths shorter than blue include light whose emission spectrum peak wavelength is between 100 nm and 400 nm.

[0108] If the light-emitting device 130 is configured to emit light with a wavelength shorter than blue, it is preferable to provide a layer 12B that converts the light emitted by the light-emitting device 130 into blue light and transmits blue light, superimposed on the light-emitting device 130. It is also preferable to provide a colored layer at a position that overlaps with the light-emitting device 130 via layer 12B.

[0109] Thus, for the sub-pixel 11B that emits blue light, a configuration using a color conversion layer, or a configuration using a combination of a color conversion layer and a coloring layer, can also be applied.

[0110] Furthermore, if the light-emitting devices 130 in the sub-pixels 11R and 11G are configured to emit light with a wavelength shorter than blue, it is preferable that the color conversion layers 12R and 12G can also convert light with a wavelength shorter than blue into red or green light.

[0111] It is preferable to have a protective layer 131 on the light-emitting device 130. Providing the protective layer 131 can improve the reliability of the light-emitting device. The protective layer 131 may be a single layer or a laminated structure of two or more layers.

[0112] The conductivity of the protective layer 131 is not required. The protective layer 131 can be at least one of an insulating film, a semiconductor film, and a conductive film.

[0113] The presence of an inorganic film in the protective layer 131 prevents oxidation of the second electrode 102 and suppresses the intrusion of impurities (such as moisture and oxygen) into the light-emitting device 130, thereby suppressing degradation of the light-emitting device and improving the reliability of the display device.

[0114] For the protective layer 131, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxidative nitride insulating film, and an oxidative nitride insulating film can be used. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum nitride film.

[0115] The protective layer 131 preferably has a nitride insulating film or a nitride oxide insulating film, and more preferably has a nitride insulating film.

[0116] Furthermore, the protective layer 131 may also be an inorganic film containing In-Sn oxide (also known as ITO), In-Zn oxide, Ga-Zn oxide, Al-Zn oxide, or indium gallium zinc oxide (also known as In-Ga-Zn oxide, IGZO). The inorganic film is preferably highly resistive, and more specifically, it is preferably more resistive than the second electrode 102. The inorganic film may further contain nitrogen.

[0117] When the light emitted from a light-emitting device is extracted via a protective layer 131, it is preferable that the protective layer 131 has high transmittance to visible light. For example, ITO, IGZO, and aluminum oxide are preferred because they are inorganic materials with high transmittance to visible light.

[0118] As the protective layer 131, for example, a laminated structure of an aluminum oxide film and a silicon nitride film on the aluminum oxide film, or a laminated structure of an aluminum oxide film and an IGZO film on the aluminum oxide film can be used. By using such a laminated structure, it is possible to suppress impurities (water, oxygen, etc.) from entering the EL layer.

[0119] Furthermore, the protective layer 131 may have an organic film. For example, the protective layer 131 may have both an organic film and an inorganic film.

[0120] The protective layer 131 may have a two-layer structure formed using different film deposition methods. Specifically, the first layer of the protective layer 131 may be formed using the ALD method, and the second layer of the protective layer 131 may be formed using the sputtering method.

[0121] In Figure 1B, the upper end of the first electrode 101 is not covered by an insulating layer. Therefore, the spacing between adjacent light-emitting devices can be made extremely narrow. Consequently, a high-definition or high-resolution display device can be made.

[0122] Although not shown in the figures, an insulating layer may be provided to cover the upper end of the first electrode 101. The organic compound layer 150 can have a portion that contacts the first electrode 101 and a portion that contacts the insulating layer. The insulating layer can be a single-layer structure or a multi-layer structure using one or both of an inorganic insulating film and an organic insulating film.

[0123] Examples of organic insulating materials that can be used for the insulating layer covering the end of the first electrode 101 include acrylic resin, epoxy resin, polyimide resin, polyamide resin, polyimidoamide resin, polysiloxane resin, benzocyclobutene resin, and phenolic resin. Furthermore, inorganic insulating films that can be used for the protective layer 131 can be used as the inorganic insulating film for the insulating layer.

[0124] When an inorganic insulating film is used as the insulating layer covering the end of the first electrode 101, impurities are less likely to enter the light-emitting device 130 compared to when an organic insulating film is used, thereby improving the reliability of the light-emitting device 130. When an organic insulating film is used as the insulating layer covering the end of the first electrode 101, the step coverage is higher compared to when an inorganic insulating film is used, and it is less affected by the shape of the pixel electrode. Therefore, short circuits in the light-emitting device 130 can be prevented. Specifically, when an organic insulating film is used as the insulating layer, the shape of the insulating layer can be processed into a tapered shape or the like.

[0125] The sides of the first electrode 101 and the organic compound layer 150 are covered by insulating layers 125 and 127. This prevents the common layer 151 (or the second electrode 102) from coming into contact with the sides of the first electrode 101 and the organic compound layer 150, thereby suppressing short circuits in the light-emitting device. This improves the reliability of the light-emitting device.

[0126] The insulating layer 125 preferably covers at least one of the side surfaces of the first electrode 101 and the organic compound layer 150, and more preferably covers both the side surfaces of the first electrode 101 and the organic compound layer 150. The insulating layer 125 can be configured to be in contact with the respective side surfaces of the first electrode 101 and the organic compound layer 150.

[0127] The insulating layer 127 is provided on the insulating layer 125 so as to fill the recesses formed in the insulating layer 125. The insulating layer 127 can be configured to overlap with the sides of the first electrode 101 and the organic compound layer 150 via the insulating layer 125.

[0128] By providing insulating layers 125 and 127, the gaps between adjacent island-shaped layers can be filled, thereby reducing the unevenness of the surface of the layer (for example, the second electrode 102) formed on the island-shaped layers, making it flatter. Consequently, the coverage of the second electrode 102 can be improved, and step breaks in the second electrode 102 can be prevented.

[0129] The common layer 151 and the second electrode 102 are provided on the organic compound layer 150, the insulating layer 125, and the insulating layer 127. Before the insulating layer 125 and the insulating layer 127 are provided, a step difference exists due to the region where the first electrode 101 and the organic compound layer 150 are provided and the region where the first electrode 101 and the organic compound layer 150 are not provided (the region between the light-emitting devices). In one embodiment of the present invention, the presence of the insulating layer 125 and the insulating layer 127 can flatten this step difference and improve the coverage of the common layer 151 and the second electrode 102. Therefore, connection failures due to step breaks can be suppressed. In addition, it is possible to suppress the local thinning of the second electrode 102 and the increase in electrical resistance caused by the step difference.

[0130] To improve the flatness of the formation surfaces of the common layer 151 and the second electrode 102, it is preferable that the heights of the upper surfaces of the insulating layer 125 and the insulating layer 127 coincide with or approximately coincide with the height of the upper surface at the edge of the organic compound layer 150. Furthermore, it is preferable that the upper surface of the insulating layer 127 has a flat shape, but it may also have convex portions, convex curved surfaces, concave curved surfaces, or recesses.

[0131] Furthermore, the insulating layer 125 or insulating layer 127 can be provided in contact with the island-shaped organic compound layer 150. This prevents the organic compound layer 150 from peeling off. The close contact between the insulating layer and the organic compound layer 150 provides the effect of fixing or bonding adjacent organic compound layers 150 to each other. This improves the reliability of the light-emitting device and increases the manufacturing yield of the light-emitting device.

[0132] It is also possible to omit either the insulating layer 125 or the insulating layer 127. For example, by forming a single-layer insulating layer 125 using an inorganic material, the insulating layer 125 can be used as a protective insulating layer for the organic compound layer 150. This can improve the reliability of the display device. Alternatively, by forming a single-layer insulating layer 127 using an organic material, for example, the space between adjacent organic compound layers 150 can be filled with the insulating layer 127 and flattened. This can improve the coverage of the second electrode 102 (upper electrode) formed on the organic compound layer 150 and the insulating layer 127.

[0133] The insulating layer 125 has a region that is in contact with the side surface of the organic compound layer 150 and functions as a protective insulating layer for the organic compound layer 150. By providing the insulating layer 125, it is possible to suppress the intrusion of impurities (oxygen, moisture, etc.) into the interior from the side surface of the organic compound layer 150, resulting in a highly reliable display device.

[0134] The insulating layer 125 can be an insulating layer having an inorganic material. For example, inorganic insulating films such as oxide insulating films, nitride insulating films, oxidative nitride insulating films, and nitride oxide insulating films can be used for the insulating layer 125. The insulating layer 125 may be a single layer or a laminated structure. Examples of oxide insulating films include silicon oxide film, aluminum oxide film, magnesium oxide film, indium gallium zinc oxide film, gallium oxide film, germanium oxide film, yttrium oxide film, zirconium oxide film, lanthanum oxide film, neodymium oxide film, hafnium oxide film, and tantalum oxide film. Examples of nitride insulating films include silicon nitride film and aluminum nitride film. Examples of oxidative nitride insulating films include silicon oxidative nitride film and aluminum oxidative nitride film. Examples of nitride oxide insulating films include silicon nitride film and aluminum nitride film. In particular, aluminum oxide is preferred because it has a high selectivity ratio with the EL layer during etching and has the function of protecting the EL layer in the formation of the insulating layer 127 described later. In particular, by applying an inorganic insulating film such as an aluminum oxide film, a hafnium oxide film, or a silicon oxide film formed by the ALD method to the insulating layer 125, it is possible to form an insulating layer 125 with fewer pinholes and excellent function in protecting the EL layer. Alternatively, the insulating layer 125 may have a laminated structure of a film formed by the ALD method and a film formed by the sputtering method. For example, the insulating layer 125 may have a laminated structure of an aluminum oxide film formed by the ALD method and a silicon nitride film formed by the sputtering method.

[0135] In this specification, "oxide nitride" refers to a material in which the oxygen content is greater than the nitrogen content, and "nitride oxide" refers to a material in which the nitrogen content is greater than the oxygen content. For example, when "silicon oxynitride" is written, it refers to a material in which the oxygen content is greater than the nitrogen content, and when "silicon nitride oxide" is written, it refers to a material in which the nitrogen content is greater than the oxygen content.

[0136] Preferably, the insulating layer 125 functions as a barrier insulating layer against at least one of water and oxygen. Furthermore, preferably, the insulating layer 125 has the function of suppressing the diffusion of at least one of water and oxygen. Also, preferably, the insulating layer 125 has the function of capturing or fixing (also known as gettering) at least one of water and oxygen.

[0137] The insulating layer 125 has the function of a barrier insulating layer or a gettering function, thereby suppressing the intrusion of impurities (typically at least one of water and oxygen) that could diffuse from the outside into each light-emitting device. This configuration makes it possible to provide a highly reliable light-emitting device and, furthermore, a highly reliable display device.

[0138] Furthermore, it is preferable that the insulating layer 125 has a low impurity concentration. This prevents impurities from mixing from the insulating layer 125 into the EL layer and degrading the EL layer. Also, by lowering the impurity concentration in the insulating layer 125, the barrier properties against at least one of water and oxygen can be improved. For example, it is desirable that the insulating layer 125 has a sufficiently low hydrogen concentration and a sufficiently low carbon concentration, preferably both.

[0139] Methods for forming the insulating layer 125 include sputtering, CVD, pulsed laser deposition (PLD), and ALD. The insulating layer 125 is preferably formed using the ALD method, which provides good coverage.

[0140] By increasing the substrate temperature when forming the insulating layer 125, it is possible to form an insulating layer 125 with a low impurity concentration and high barrier properties against at least one of water and oxygen, even if the film thickness is thin. Therefore, the substrate temperature is preferably 60°C or higher, more preferably 80°C or higher, more preferably 100°C or higher, and more preferably 120°C or higher. On the other hand, since the insulating layer 125 is formed after forming island-shaped EL layers, it is preferable to form it at a temperature lower than the heat resistance temperature of the EL layers. Therefore, the substrate temperature is preferably 200°C or lower, more preferably 180°C or lower, more preferably 160°C or lower, more preferably 150°C or lower, and more preferably 140°C or lower.

[0141] Indicators of heat resistance temperature include, for example, the glass transition temperature, softening temperature, melting point, thermal decomposition temperature, and 5% weight loss temperature. The heat resistance temperature of the EL layer can be any of these temperatures, preferably the lowest of these temperatures.

[0142] The insulating layer 127 provided on the insulating layer 125 has the function of flattening the recess in the insulating layer 125 formed between adjacent light-emitting devices. In other words, the presence of the insulating layer 127 has the effect of improving the flatness of the formation surface of the second electrode 102. As the insulating layer 127, an insulating layer having an organic material can be suitably used. For example, as the insulating layer 127, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be applied. Alternatively, as the insulating layer 127, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used. Furthermore, a photosensitive resin can be used as the insulating layer 127. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0143] The insulating layer 127 may be made of a material that absorbs visible light. By absorbing the light emitted from the light-emitting device, the insulating layer 127 can suppress light leakage (stray light) from the light-emitting device to adjacent light-emitting devices through the insulating layer 127. This improves the display quality of the display device. Furthermore, since the display quality can be improved without using a polarizing plate in the display device, the display device can be made lighter and thinner.

[0144] Examples of materials that absorb visible light include materials containing pigments such as black, materials containing dyes, light-absorbing resin materials (e.g., polyimide), and resin materials that can be used as color filters (color filter materials). In particular, it is preferable to use a resin material that is a mixture of two or three or more color filter materials, as this can enhance the visible light shielding effect. Mixing three or more color filter materials in particular makes it possible to create a black or near-black resin layer.

[0145] The display device of this embodiment can reduce the distance between light-emitting devices. Specifically, the distance between light-emitting devices, the distance between EL layers, or the distance between pixel electrodes can be less than 10 μm, 5 μm or less, 3 μm or less, 2 μm or less, 1 μm or less, 500 nm or less, 200 nm or less, 100 nm or less, 90 nm or less, 70 nm or less, 50 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, or 10 nm or less. In other words, the display device of this embodiment has a region where the distance between two adjacent organic compound layers 150 is 1 μm or less, preferably a region where the distance is 0.5 μm (500 nm) or less, and more preferably a region where the distance is 100 nm or less.

[0146] A light-shielding layer may be provided on the side of the substrate 40 facing the resin layer 32. Various optical components can be placed on the outside of the substrate 40. Examples of optical components include polarizing plates, phase difference plates, light diffusion layers (such as diffusion films), anti-reflective layers, and light-collecting films. Surface protection layers such as an antistatic film to suppress the adhesion of dust, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact absorption layer may also be placed on the outside of the substrate 40. For example, providing a glass layer or a silica layer (SiOx layer) as a surface protection layer is preferable as it can suppress surface contamination and the occurrence of scratches. Alternatively, DLC (diamond-like carbon), aluminum oxide (AlOx), polyester-based materials, or polycarbonate-based materials may be used as the surface protection layer. It is preferable to use a material with high transmittance to visible light for the surface protection layer. It is also preferable to use a material with high hardness for the surface protection layer.

[0147] The substrate 40 can be made of glass, quartz, ceramic, sapphire, resin, metal, alloy, semiconductor, etc. The substrate on the side that extracts light from the light-emitting device should be made of a material that transmits the light. Using a flexible material for the substrate 40 can increase the flexibility of the display device. Alternatively, a polarizing plate may be used as the substrate 40.

[0148] As the substrate 40, various materials can be used, including polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. Glass with a thickness sufficient to provide flexibility may also be used for the substrate 40.

[0149] Furthermore, when a circular polarizing plate is superimposed on a display device, it is preferable to use a substrate with high optical isotropy for the substrate of the display device. A substrate with high optical isotropy has low birefringence (or a small amount of birefringence).

[0150] For substrates with high optical isotropy, the absolute value of the retardation (phase difference) is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less.

[0151] Examples of films with high optical isotropy include triacetylcellulose (TAC, also known as cellulose triacetate) film, cycloolefin polymer (COP) film, cycloolefin copolymer (COC) film, and acrylic film.

[0152] Furthermore, when using a film as the substrate, the film may absorb water, potentially causing wrinkles or other shape changes in the display panel. Therefore, it is preferable to use a film with low water absorption for the substrate. For example, it is preferable to use a film with a water absorption rate of 1% or less, more preferable to use a film with a water absorption rate of 0.1% or less, and even more preferable to use a film with a water absorption rate of 0.01% or less.

[0153] Furthermore, by fabricating light-emitting devices using a lithography method to process organic compound layers, the spacing between adjacent light-emitting devices, adjacent EL layers, adjacent sidewall insulating layers, or adjacent pixel electrodes can be narrowed to less than 10 μm, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, 1.5 μm or less, 1 μm or less, or 0.5 μm or less. In addition, by using, for example, exposure equipment for LSIs, the spacing between adjacent light-emitting devices, adjacent EL layers, adjacent sidewall insulating layers, or adjacent pixel electrodes can be narrowed to, for example, 500 nm or less, 200 nm or less, 100 nm or less, or even 50 nm or less in a process on a Si Wafer. However, if the spacing between light-emitting devices is too narrow, there is a risk of light leakage. Furthermore, in order to narrow the space between color conversion layers, it is necessary to narrow the partition wall 20, which increases the possibility that the color conversion layer may pass over the partition wall 20 and invade the adjacent pixel when the color conversion layer is formed by coating.

[0154] Therefore, as shown in Figure 1B, the edges of the color conversion layer 12R, the color conversion layer 12G, and the layer 12B are positioned inward from the edges of the light-emitting device 130 (the edges of the pixel electrodes). In this case, the side walls of the partition wall 20 are structured so that any of the color conversion layer 12R, the color conversion layer 12G, and the layer 12B, the inorganic film 22, and the light-emitting device 130 overlap each other. By positioning the edges of the color conversion layer 12R, the color conversion layer 12G, and the layer 12B inward from the edges of the light-emitting device 130, the partition wall 20 does not need to be made excessively narrow, thus reducing the possibility that the color conversion layer may overflow the partition wall and penetrate into the adjacent pixel when the color conversion layer is formed by coating. Furthermore, the risk of light leakage can be reduced.

[0155] Figure 2A shows a modified example of the cross-sectional view between the dashed lines X1 and X2 in Figure 1A. In the cross-sectional view shown in Figure 2A, the top surface of the display device 100 is shown at the bottom.

[0156] In the unit 31 shown in Figure 2A, a partition wall 120 is provided between two adjacent light-emitting devices 130 (first light-emitting device and second light-emitting device) to divide the organic compound layer 150. The partition wall 120 is a conductive structure with an inverse tapered shape. It can also be said that the upper part of the partition wall 120 protrudes laterally more than the lower part. The partition wall 120 is formed to be located between two adjacent first electrodes 101. The partition wall 120 is also provided to surround one of the first electrodes 101. By depositing the organic compound layer 150 on the partition wall 120, a step is created by the partition wall 120, and the organic compound layer 150 can be divided for each light-emitting device.

[0157] In this specification, "step breakage" refers to the phenomenon in which a layer, film, electrode, etc., is divided due to the shape of the surface on which it is formed (for example, a step or other difference in height).

[0158] Furthermore, in the unit 31 shown in Figure 2A, a second electrode 102 is provided so as to cover the organic compound layer 150 and the partition wall 120. When forming the second electrode 102, it is preferable to use a film formation method that provides higher step coverage than that used for the organic compound layer 150. This allows a configuration in which a part of the second electrode 102 covers the edge of the organic compound layer 150 and also contacts a part of the partition wall. In addition, a protective layer 131 is provided that covers the second electrode 102 and the partition wall 120. It is preferable to form the protective layer 131 using the ALD method, which provides extremely high step coverage. This makes it possible to obtain a good protective film with few defects such as pinholes.

[0159] More specifically, in the unit 31 shown in Figure 2A, an insulating layer 133 is provided covering the ends of each first electrode 101 of each light-emitting device. The portion of the first electrode 101 that is not covered by the insulating layer 133 functions as the light-emitting region of the light-emitting device 130. The ends of the insulating layer 133 are preferably tapered. Note that the insulating layer 133 may be omitted if it is not needed.

[0160] In this specification, an object is said to have a tapered shape if the angle between the side surface of the object and the contact surface between the object and the surface to be formed (also called the taper angle) is greater than 0 degrees and less than 90 degrees, and the cross-sectional shape has a thickness that increases continuously from the end. On the other hand, an object is said to have an inverse tapered shape if the angle between the side surface of the object and the contact surface between the object and the surface to be formed is greater than 90 degrees and less than 180 degrees.

[0161] The insulating layer 133 preferably contains an organic resin. By using an organic resin as the insulating layer 133, adhesion with the organic compound layer 150 can be improved, thereby improving the manufacturing yield. Furthermore, by using an organic resin in the insulating layer 133, its surface can be made flat or gently curved. Therefore, the coverage of the film formed on the insulating layer 133 can be improved.

[0162] Examples of materials that can be used for the insulating layer 133 include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins.

[0163] Furthermore, a partition wall 120 is provided on the insulating layer 133. The partition wall 120 is conductive and has an inverse tapered shape. Additionally, an organic compound layer 150a may be formed on the partition wall 120. The organic compound layer 150a has the same configuration as the organic compound layer 150.

[0164] Since the conductive partition wall 120 is in contact with the second electrode 102, it can be said that the second electrodes 102 between adjacent light-emitting devices are connected via the partition wall 120. Furthermore, since the partition wall 120 is arranged in a grid pattern so as to weave between the light-emitting devices 130, it can be said that the second electrodes 102 of all light-emitting devices 130 are connected via the partition wall 120. In addition, the partition wall 120 also functions as wiring that supplies potential to the second electrode 102 of each light-emitting device 130.

[0165] The partition wall 120 can be made of various conductive materials. For example, metals, alloys, oxide conductive materials, nitride conductive materials, etc., can be used. For example, metallic materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metallic materials, can be used.

[0166] Furthermore, it is preferable that the partition wall 120 contains an oxide conductive material containing indium. This is preferable because it can reduce the contact resistance with the second electrode 102. For example, an oxide conductive material such as indium tin oxide can be used. Other materials that can be used include indium oxide, indium zinc oxide, indium titanium oxide, indium gallium zinc oxide, indium tin zinc oxide, indium titanium zinc oxide, and indium gallium tin zinc oxide. Alternatively, indium tin oxide containing silicon can also be used. In addition, an oxide conductive material that does not contain indium, such as zinc oxide, may be used.

[0167] In the unit 31 shown in Figure 2A, the organic compound layer 150 has a region in contact with the upper surface of the first electrode 101 and a region in contact with the surface of the insulating layer 133. The end of the organic compound layer 150 is located on the insulating layer 133. The second electrode 102 covers the end of the organic compound layer 150 and is in contact with the upper surface of the insulating layer 133 and a part of the side surface of the partition wall 120.

[0168] Figure 3A shows two light-emitting devices 130, an insulating layer 133 located between them, a partition wall 120, and an enlarged view of the vicinity thereof.

[0169] As shown in Figure 3A, the insulating layer 133 has its end located on the first electrode 101. The space between the end of the insulating layer 133 and the end of the most protruding part of the partition wall 120 is referred to as the gap Sx. The presence of the gap Sx allows the organic compound layer 150 to be formed such that, when the organic compound layer 150 is formed, the end of the organic compound layer 150, which is stepped off by the partition wall 120, is located on the insulating layer 133 and not on the first electrode 101. For example, if the end of the organic compound layer 150 is located on the first electrode 101, the second electrode 102 covering the organic compound layer 150 may come into contact with the first electrode 101, potentially causing an electrical short circuit. Therefore, it is important to provide a gap Sx between the end of the insulating layer 133 and the partition wall 120 in order to ensure that the end of the organic compound layer 150 is reliably located on the insulating layer 133. Although the gap in the X direction has been described here, the same applies to the gap in the Y direction.

[0170] Preferably, the height h of the partition wall 120 is greater than the thickness of the organic compound layer 150. Furthermore, the taper angle θ of the partition wall 120 can be greater than 90 degrees and less than 180 degrees. The closer the taper angle θ is to 90 degrees, the easier it is for the partition wall 120 and the second electrode 102 to come into contact during the formation of the second electrode 102. However, the smaller the gap between the end of the organic compound layer 150 and the partition wall 120, the less space may be available for the second electrode 102 and the partition wall 120 to come into contact. Also, the closer the taper angle θ is to 180 degrees, the more likely the organic compound layer 150 is to break in steps, while making it difficult to bring the second electrode 102 and the partition wall 120 into contact. Therefore, the taper angle θ should be, for example, between 95 degrees and 150 degrees, preferably between 100 degrees and 135 degrees. Furthermore, if the coverage of the second electrode 102 is sufficiently high, an even larger taper angle θ can be used. For example, the taper angle θ can be set to 105 degrees or more and 175 degrees or less, preferably 120 degrees or more and 170 degrees or less.

[0171] Here, the taper angle θ is shown as the angle between the bottom and side surfaces of the partition wall 120. However, as shown in Figure 3A, it can also be expressed as the angle (taper angle θ') between the side surface of the partition wall 120 and the upper surface of the underlayer (insulating layer 133 in this case) that does not come into contact with the partition wall 120. In that case, it can be expressed as θ' ​​= 180 degrees - θ (where both θ and θ' are between 0 and 180 degrees). That is, the preferred range for the taper angle θ' can be expressed as 30 degrees to 85 degrees, preferably 45 degrees to 80 degrees, or 5 degrees to 75 degrees, preferably 10 degrees to 60 degrees. When deciding which angle to use to express the taper angle, one should choose the one that is easier to measure, taking into account the surface shape of the underlayer (e.g., insulating layer 133).

[0172] By using a configuration like the unit 31 shown in Figure 2A, it is possible to create different organic compound layers between adjacent light-emitting devices. Compared to cases where the organic compound layers are in contact with each other or a common organic compound layer is used, leakage current through the organic compound layer can be substantially eliminated. This prevents unintended light emission and enables the realization of a display device with high contrast and high display quality. Furthermore, since the organic compound layer 150 is covered by the second electrode 102 and the protective layer 131 within the region surrounded by the partition wall 120, it prevents the diffusion of impurities such as moisture into the organic compound layer 150, enabling the realization of a highly reliable display device. In addition, this configuration does not require the use of a metal mask, and all processing of the organic compound layer 150, etc., can be performed using photolithography, making it easier to achieve high resolution and high aperture ratio compared to cases where a metal mask is used.

[0173] In Figures 2 and 3, the height of the partition wall 120 is depicted as being greater than its width, but in reality, the cross-sectional width may be larger than the height.

[0174] Furthermore, while Figures 2 and 3A show an example where the second electrode 102 is continuous from the side to the top of the partition wall 120 without being stepped by the partition wall 120, the second electrode 102 may be stepped. Figure 3B shows an example where the second electrode 102 is stepped. In this case, the partition wall 120 has a conductive layer 102a that covers the side and top surfaces of the organic compound layer 150a. The conductive layer 102a contains the same material as the second electrode 102. The protective layer 131 also has portions that are in contact with the side surfaces of the partition wall 120. With this configuration, the entire second electrode 102, including its end, can be covered by the protective layer 131 and the partition wall 120. This prevents water and other substances from diffusing into the light-emitting device 130 from the outside via the second electrode 102, and prevents the second electrode 102 itself from deteriorating.

[0175] The partition wall 120 shown in Figure 3A, etc., is an example having an inverse tapered shape. The shape of the partition wall 120 exemplified in Figure 3A, etc., can also be described as having a roughly trapezoidal shape in cross-section, where the length of the upper base is longer than the length of the lower base. However, the shape of the partition wall 120 is not limited to this, and various shapes can be taken as long as the organic compound layer 150 can be stepped. The partition wall 120 can also have a symmetrical shape in cross-section. If the upper surface of the partition wall 120 is flat, the shape of the partition wall 120 in cross-section will be a polygonal shape with an even number of corners. Examples of other cross-sectional shapes of the partition wall 120 will be described below.

[0176] The examples shown in Figures 4A and 4B are examples in which the side surface of the partition wall 120 has a curved shape. In Figure 4A, it has a concave curved surface, and in Figure 4B, it has a convex curved surface.

[0177] When the side surface of the partition wall 120 has a curved shape, it is difficult to uniquely determine the taper angle θ. In such cases, as shown in Figures 4A and 4B, a straight line connecting the point of the widest part of the partition wall 120 in a cross-sectional view and the point of the end of the contact surface between the partition wall 120 and the underlying film (insulating layer 133) can be assumed to be a hypothetical side surface of the partition wall 120, and the angle between this straight line and the contact surface between the partition wall 120 and the underlying film (insulating layer 133) can be defined as the taper angle θ.

[0178] Here, the partition wall 120 only needs to have a tapered shape in a portion including at least the part that is in contact with the substrate film, and the shape of the part above that is not specified. As shown in Figure 4C, the partition wall 120 can be divided into a lower part 120B (also called the first part) which has a tapered shape, and an upper part 120T (also called the second part) which is located above the lower part 120B. Since the upper part 120T can take various shapes, its shape is not explicitly shown here and is indicated by a dashed line. Below, examples of upper parts 120T with different shapes will be described.

[0179] Figure 4D shows an example where the upper part 120T has a rectangular shape in cross-section. Figures 4E and 4F show examples where the upper part 120T has a trapezoidal shape in cross-section, where the length of the upper side (also called the upper base) is longer than the length of the lower side (also called the lower base). Figure 4E shows an example where the height of the upper part 120T is smaller than the lower part 120B, and Figure 4F shows an example where the heights of the upper part 120T and the lower part 120B are roughly the same. The partition walls 120 shown in Figures 4D, 4E, and 4F can also be said to have a hexagonal shape in cross-section.

[0180] Figure 4G shows an example where the partition wall 120 has an octagonal shape in cross-sectional view. In Figure 4G, a portion of the side surface of the partition wall 120 is approximately perpendicular to the surface to be formed.

[0181] Figures 4H and 4I are modified examples of Figures 4A and 4B, respectively, and are examples having a curved lower part 120B and an upper part 120T that has a trapezoidal shape in cross-sectional view.

[0182] Although the above shows that the side surface of the partition wall 120 has corners, depending on the processing method of the partition wall 120, the corners may be rounded. In particular, when the partition wall 120 is formed by an isotropic etching method such as wet etching, the corners tend to be rounded.

[0183] Furthermore, as described above, the organic compound layer 150 of the light-emitting device 130 has a plurality of light-emitting units. For example, the organic compound layer 150 has a first light-emitting unit 501, an intermediate layer 160, and a second light-emitting unit 502. It is preferable that the intermediate layer 160 has a layer configuration comprising a first organic compound, a second organic compound, and a metal material. In the case of the configuration of the light-emitting device 130 having unit 31 shown in Figure 2A, if the side surface of the intermediate layer 160 is exposed to the side surface of the organic compound layer 150, there is a risk of electrical short circuit occurring due to contact between the intermediate layer 160 and the second electrode 102. Therefore, it is more preferable to provide the organic compound layer 150 such that the side surface of the intermediate layer 160 is not exposed to the side surface of the organic compound layer 150.

[0184] Figures 2B and 2C show examples of enlarged views of the light-emitting device 130 of the unit 31 shown in Figure 2A.

[0185] In Figure 2B, the organic compound layer 150 has a first light-emitting unit 501, an intermediate layer 160, and a second light-emitting unit 502, with the edges of the intermediate layer 160 located inward from the edges of the first light-emitting unit 501 and the second light-emitting unit. With this configuration, the sides of the intermediate layer 160 are not exposed to the sides of the organic compound layer 150, thus preventing electrical short circuits from occurring due to contact between the intermediate layer 160 and the second electrode 102.

[0186] In Figure 2C, the organic compound layer 150 includes the first light-emitting unit 501, the intermediate layer 160, and the second light-emitting unit 502, as well as a layer 510 that covers the sides of the first light-emitting unit 501, the sides of the intermediate layer 160, and the top and sides of the second light-emitting unit 502. The layer 510 can be made of a carrier transport material or the like. The layer 510 may also have, for example, an electron injection layer or a hole injection layer. Alternatively, the layer 510 may have an electron transport layer and an electron injection layer laminated together, or a hole transport layer and a hole injection layer laminated together. Even with such a configuration, since the sides of the intermediate layer 160 are not exposed to the sides of the organic compound layer 150, it is possible to prevent electrical short circuits from occurring due to contact between the intermediate layer 160 and the second electrode 102.

[0187] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, the configuration examples can be appropriately combined.

[0188] (Embodiment 2) In this embodiment, an example of a light-emitting device that can be used in a display device according to one aspect of the present invention will be described with reference to Figures 5 to 11.

[0189] Figure 5A shows a schematic diagram of two adjacent light-emitting devices, light-emitting device 130a and light-emitting device 130b, which are included in a display device and formed on the same insulating surface, in order to illustrate a light-emitting device that can be used in a display device according to one embodiment of the present invention. Light-emitting device 130a and light-emitting device 130b are light-emitting devices in which a part of the organic compound layer is processed using a lithography method. Furthermore, light-emitting device 130a and light-emitting device 130b are tandem-type light-emitting devices having a structure in which multiple light-emitting units are stacked with an intermediate layer in between.

[0190] The light-emitting device 130a is located on an insulating layer 175 and has a first electrode 101a including an anode, a second electrode 102 including a cathode, and an organic compound layer 103a. The organic compound layer 103a is located between the first electrode 101a and the second electrode 102. The organic compound layer 103a also has a structure in which a first light-emitting unit 501a and a second light-emitting unit 502a are laminated with an intermediate layer 160a in between. The first light-emitting unit 501a has a first light-emitting layer 113a_1. The intermediate layer 160a has a first layer 161a and a second layer 162a. The second light-emitting unit 502a has a second light-emitting layer 113a_2 and an electron injection layer 115. It can also be said that the intermediate layer 160a is located between the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2.

[0191] In the light-emitting device 130a, each layer of the organic compound layer 103a, except for the electron injection layer 115, is processed by lithography. Therefore, each layer of the organic compound layer 103a, except for the electron injection layer 115, is independent of the adjacent light-emitting device, light-emitting device 130b. Furthermore, the edges (contours) of each layer of the organic compound layer 103a, except for the electron injection layer 115, coincide or roughly coincide with the substrate in a direction perpendicular to it. That is, the first light-emitting layer 113a_1, the intermediate layer 160a (first layer 161a and second layer 162a), and the second light-emitting layer 113a_2 are independent of the first light-emitting layer 113b_1, the intermediate layer 160b (first layer 161b and second layer 162b), and the second light-emitting layer 113b_2. Furthermore, the edges (contours) of the first light-emitting layer 113a_1, the intermediate layer 160a (the first layer 161a and the second layer 162a), and the second light-emitting layer 113a_2 coincide or roughly coincide with the substrate in a direction perpendicular to it.

[0192] The light-emitting device 130b is located on an insulating layer 175 and has a first electrode 101b including an anode, a second electrode 102 including a cathode, and an organic compound layer 103b. The organic compound layer 103b is located between the first electrode 101b and the second electrode 102. The organic compound layer 103b also has a structure in which a first light-emitting unit 501b and a second light-emitting unit 502b are laminated with an intermediate layer 160b in between. The first light-emitting unit 501b has a first light-emitting layer 113b_1. The intermediate layer 160b has a first layer 161b and a second layer 162b. The second light-emitting unit 502b has a second light-emitting layer 113b_2 and an electron injection layer 115. It can also be said that the intermediate layer 160b is located between the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2.

[0193] In the light-emitting device 130b, each layer of the organic compound layer 103b, except for the electron injection layer 115, is processed by lithography. Therefore, each layer of the organic compound layer 103b, except for the electron injection layer 115, is independent of (or separated from) the adjacent light-emitting device, light-emitting device 130a. Furthermore, the edges (contours) of each layer of the organic compound layer 103b, except for the electron injection layer 115, coincide or roughly coincide with the substrate in a direction perpendicular to it. That is, the first light-emitting layer 113b_1, the intermediate layer 160b (first layer 161b and second layer 162b), and the second light-emitting layer 113b_2 are independent of the first light-emitting layer 113a_1, the intermediate layer 160a (first layer 161a and second layer 162a), and the second light-emitting layer 113a_2. Furthermore, the edges (contours) of the first light-emitting layer 113b_1, the intermediate layer 160b (the first layer 161b and the second layer 162b), and the second light-emitting layer 113b_2 coincide or roughly coincide with the substrate in a direction perpendicular to it.

[0194] In this embodiment, the electron injection layer 115 corresponds to the common layer 151 in Embodiment 1. Also, in this embodiment, the structure obtained by removing the electron injection layer 115 from the organic compound layer 103a and the organic compound layer 103b corresponds to the organic compound layer 150 in Embodiment 1.

[0195] It is preferable that the electron injection layer 115 and the second electrode 102 are formed after processing each layer of the organic compound layer 103a other than the electron injection layer 115 and each layer of the organic compound layer 103b other than the electron injection layer 115 by lithography. In other words, it is preferable that the electron injection layer 115 and the second electrode 102 are a continuous, shared layer in the light-emitting device 130a and the light-emitting device 130b.

[0196] Using a donor material such as an alkali metal or alkaline earth metal, or a compound thereof, for the electron injection layer 115 is preferable because it allows for a lower voltage to be used in the light-emitting device. However, when an organic compound layer having such a donor material as its outermost surface is processed using lithography, the influence of oxygen or water in the atmosphere, or chemicals or water used in the process, may cause a significant increase in the driving voltage or a drastic decrease in the current efficiency in the light-emitting device.

[0197] On the other hand, if a light-emitting device is manufactured by processing each layer of the organic compound layer, excluding the electron injection layer 115, using lithography, as in the light-emitting device 130a and light-emitting device 130b, and then forming the electron injection layer 115 and the second electrode 102, the electron injection layer 115 is less susceptible to the effects of oxygen or water in the atmosphere, or chemicals or water used in the process, thus enabling the production of a light-emitting device with good characteristics.

[0198] Furthermore, by processing the organic compound layers using lithography, the distance between organic compound layers can be narrowed compared to when mask deposition is performed. Specifically, the distance d between each layer of organic compound layer 103a other than the electron injection layer 115 and each layer of organic compound layer 103b other than the electron injection layer 115 can be narrowed to less than 10 μm, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, 1.5 μm or less, 1 μm or less, or 0.5 μm or less. In addition, by using, for example, an exposure apparatus for LSIs, the distance d can be narrowed to, for example, 500 nm or less, 200 nm or less, 100 nm or less, and even 50 nm or less in a process on a Si Wafer.

[0199] Furthermore, it is preferable that an insulating layer is provided in the gap between each layer of the organic compound layer 103a other than the electron injection layer 115 and each layer of the organic compound layer 103b other than the electron injection layer 115, thereby separating each layer of the organic compound layer 103a other than the electron injection layer 115 from each layer of the organic compound layer 103b other than the electron injection layer 115. In this case, the insulating layer has a region in contact with the electron injection layer 115 or the second electrode 102.

[0200] Furthermore, in the light-emitting device 130a, the first light-emitting unit 501a preferably has, in addition to the first light-emitting layer 113a_1, a hole injection layer 111a, a first hole transport layer 112a_1, and a first electron transport layer 114a_1. Furthermore, the second light-emitting unit 502a preferably has, in addition to the second light-emitting layer 113a_2 and the electron injection layer 115, a second hole transport layer 112a_2 and a second electron transport layer 114a_2. Furthermore, the intermediate layer 160a may be configured to have a third layer 163a between the first layer 161a and the second layer 162a. Furthermore, in cases where the anode side of the light-emitting unit is in contact with the intermediate layer 160a, as in the second light-emitting unit 502a, the second layer 162a located on the cathode side of the intermediate layer 160a can also serve as the hole injection layer of the second light-emitting unit 502a. Therefore, it may not be necessary to provide a hole injection layer in the light-emitting unit, but it may be provided.

[0201] Furthermore, in the light-emitting device 130b, the first light-emitting unit 501b preferably has, in addition to the first light-emitting layer 113b_1, a hole injection layer 111b, a first hole transport layer 112b_1, and a first electron transport layer 114b_1. Furthermore, the second light-emitting unit 502b preferably has, in addition to the second light-emitting layer 113b_2 and the electron injection layer 115, a second hole transport layer 112b_2 and a second electron transport layer 114b_2. Furthermore, the intermediate layer 160b may have a third layer 163b between the first layer 161b and the second layer 162b. Furthermore, in cases where the anode side of the light-emitting unit is in contact with the intermediate layer 160b, as in the second light-emitting unit 502b, the second layer 162b located on the cathode side of the intermediate layer 160b can also serve as the hole injection layer of the second light-emitting unit 502b. Therefore, it may not be necessary to provide a hole injection layer in the light-emitting unit, but it may be provided.

[0202] Furthermore, as shown in Figure 5A, it is preferable that the uppermost layer of the organic compound layer 103a, other than the electron injection layer 115, is the second electron transport layer 114a_2. Similarly, it is preferable that the uppermost layer of the organic compound layer 103b, other than the electron injection layer 115, is the second electron transport layer 114b_2. When processing an organic compound layer having the second electron transport layer 114a_2 and the second electron transport layer 114b_2 on its outermost surface using lithography, for example, compared to processing an organic compound layer having the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2 on its outermost surface, the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2 are less susceptible to the effects of oxygen or water in the atmosphere, or chemicals or water during the process, because they are located on the upper layers. In other words, it is preferable that each organic compound layer be processed using lithography at least above the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2, and it is more preferable that the second electron transport layer 114a_2 and the second electron transport layer 114b_2 be processed using lithography as the uppermost layer. This makes it easier to avoid deterioration of the characteristics of the light-emitting device caused by fabrication using lithography.

[0203] Figure 5A shows an example in which each organic compound layer contains two light-emitting units, but the present invention is not limited to this. Each organic compound layer may contain three or more light-emitting units. In this case, the three or more light-emitting units may use light-emitting materials that emit light of the same color, or they may use light-emitting materials that emit light of different colors. By stacking multiple light-emitting units between a pair of electrodes with an intermediate layer in between, it is possible to achieve high-brightness light emission while maintaining a low current density, and to realize a light-emitting device with good reliability. Furthermore, it is possible to realize a light-emitting device with low power consumption. In addition, although not shown in Figure 5A, each light-emitting unit may have a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc., in addition to the above configuration. Furthermore, each layer may be stacked in two or more layers.

[0204] In this specification, while one configuration of light-emitting device 130a and light-emitting device 130b may be given as an example, a similar configuration can be used for the other.

[0205] The intermediate layer 160a sandwiched between the first light-emitting unit 501a and the second light-emitting unit 502a should, for example, inject electrons into one light-emitting unit and holes into the other when a voltage is applied between the first electrode 101a and the second electrode 102. For example, in Figure 5A, when a voltage is applied such that the potential of the second electrode 102 is higher than the potential of the first electrode 101a, the intermediate layer 160a injects electrons into the first light-emitting unit 501a and holes into the second light-emitting unit 502a.

[0206] In the light-emitting device 130a illustrated in Figure 5A, by applying a voltage between a pair of electrodes (the first electrode 101a and the second electrode 102), electrons are injected from the cathode into the electron injection layer 115, and holes are injected from the anode into the hole injection layer 111a, causing a current to flow. Additionally, electrons are injected from the first layer 161a located on the anode side of the intermediate layer 160a into the first electron transport layer 114a_1 in the first light-emitting unit 501a, and holes are injected from the second layer 162a located on the cathode side of the intermediate layer 160a into the second hole transport layer 112a_2 in the second light-emitting unit 502a. Then, the injected carriers (electrons and holes) recombine to form excitons. In the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2, which have a light-emitting material, when carriers (electrons and holes) recombine and excitons are formed, the light-emitting material in the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 becomes excited, and light is emitted from the light-emitting material.

[0207] Furthermore, as shown in Figure 5A, it is preferable that the first layer 161a located on the anode side of the intermediate layer 160a is adjacent to the first electron transport layer 114a_1 and is provided between the first electron transport layer 114a_1 and the second light-emitting unit 502a. With this configuration, electrons can be efficiently injected into the first light-emitting unit 501a.

[0208] In order to reduce the driving voltage of the light-emitting device and enable efficient light emission, it is preferable to reduce the electron injection barrier from the intermediate layer to the first electron transport layer, thereby allowing smooth injection and transport of electrons generated in the intermediate layer to the first electron transport layer. For this purpose, alkali metals or alkaline earth metals or compounds thereof with a small work function are generally used for the first layer of the intermediate layer. However, these metals and compounds are susceptible to degradation by oxygen or water in the atmosphere and water or chemicals used in the lithography process, which can cause a significant increase in the driving voltage or a drastic decrease in current efficiency in the light-emitting device. Alternatively, a method can be considered in which a metal that is stable to oxygen and water in the atmosphere and resistant to water and chemicals is used for the first layer of the intermediate layer. However, such metals are stable and have low electron injection properties, so they may form an electron injection barrier between the intermediate layer 160a and the first electron transport layer 114a_1, which can lead to problems such as a high driving voltage or decreased luminescence efficiency in the light-emitting device. Therefore, in such light-emitting devices, it is preferable to use a material that is resistant to water and chemicals used in the process for the intermediate layer.

[0209] Figure 6 also shows schematic diagrams of modified versions of the light-emitting devices 130a and 130b shown in Figure 5A. Both light-emitting devices 130a and 130b are light-emitting devices in which the entire organic compound layer, including the electron injection layer, is processed using lithography.

[0210] The organic compound layer 103a of the light-emitting device 130a shown in Figure 6 has an electron injection layer 115a that is independent of the adjacent light-emitting device 130b and has edges (contours) that coincide or roughly coincide perpendicularly with the substrate and each other layer. Similarly, the organic compound layer 103b of the light-emitting device 130b shown in Figure 6 has an electron injection layer 115b that is independent of the adjacent light-emitting device 130a and has edges (contours) that coincide or roughly coincide perpendicularly with the substrate and each other layer. Note that the configuration of the light-emitting devices 130a and 130b and their surroundings shown in Figure 6 are the same as the configuration shown in Figure 5A, so their explanation is omitted.

[0211] As shown in Figure 6, in a light-emitting device in which the entire organic compound layer including the electron injection layer is processed using lithography, it is preferable to use materials that are resistant to water and chemicals used during the process for the electron injection layer and the intermediate layer.

[0212] Therefore, in a display device according to one aspect of the present invention, it is preferable to use a light-emitting device to which the configuration of the layer 200 described below is applied to at least one of the first layer (161a, 161b) and the electron injection layer (115, 115a, 115b) of the above-mentioned intermediate layer (160a, 160b).

[0213] [Layer 200] As shown in Figure 5B, layer 200 is a layer having a first organic compound 161_1, a second organic compound 161_2, and a metallic material 161_M, and in layer 200, these materials form a composite material. In this composite material, the first organic compound 161_1 and the metallic material 161_M interact to form a donor level (SOMO (Singly Occupied Molecular Orbital) level or HOMO (Highest Occupied Molecular Orbital) level), and can further function as an electron donor for the second organic compound 161_2. With this configuration, it is possible to form a layer that has good electron injection characteristics and is resistant to oxygen and water in the atmosphere, as well as water and chemicals used in the lithography process.

[0214] Furthermore, it is preferable to apply a mixed layer to layer 200 that contains a first organic compound 161_1, a second organic compound 161_2, and a metal material 161_M. By configuring layer 200 in this way, the interaction of these materials becomes easier, making it easier for the first organic compound 161_1 and the metal material 161_M to function as electron donors for the second organic compound 161_2. In addition, a layer 200 with such a structure can be made less prone to crystallization compared to a laminated structure. Therefore, when processing a portion of the organic compound layer containing such a layer by lithography, it is possible to make the layer less prone to crystallization even when affected by oxygen or water in the atmosphere, or chemicals or water during the process. Furthermore, it is possible to prevent an increase in the driving voltage or a decrease in the current efficiency of the light-emitting device due to crystallization of the intermediate layer or electron injection layer. Therefore, by using a mixed layer rather than a laminated structure, it can be suitably used for at least one of the intermediate layer and electron injection layer of a light-emitting device in which a portion of the organic compound layer has been processed by lithography.

[0215] In layer 200, the first organic compound 161_1 and the metal material 161_M interact to form a donor level, and further function as an electron donor for the second organic compound 161_2. Therefore, by using layer 200 as the first layer (161a, 161b) of the intermediate layers (160a, 160b), electrons generated in the first layer can be easily injected into the first light-emitting unit. Alternatively, electrons generated in the second layer (second layer 162a and second layer 162b) located on the cathode side of the intermediate layer can be easily injected into the first light-emitting unit 501a. Consequently, it becomes easier to inject electrons into the first light-emitting unit 501a, thereby reducing the driving voltage of the light-emitting device and improving the luminous efficiency. Furthermore, by using layer 200 as an electron injection layer (115, 115a, 115b), the electron injection barrier from the second electrode 102 to the organic compound layer (103a, 103b) is reduced, and electrons injected from the second electrode 102 can be smoothly injected and transported to the light-emitting layer (113a, 113b). As a result, the driving voltage is reduced, and a light-emitting device with high luminescence efficiency can be obtained.

[0216] The metallic material 161_M is either a metal or a metallic compound, or both. Furthermore, it is preferable that either or both of the metal and the metallic compound contain at least one element selected from groups 3 through 14 of the periodic table. These metallic elements have low reactivity with oxygen and water in the atmosphere, as well as with water and chemicals used in the lithography process. Therefore, using either or both of such metals and metallic compounds in a light-emitting device is preferable because it offers the advantage of less degradation due to water and oxygen.

[0217] However, since metal elements from groups 3 to 14 of the periodic table have low electron injection properties, using these metal elements in a normal configuration makes it difficult to improve the characteristics of the light-emitting device, which may lead to a decrease in luminous efficiency, an increase in driving voltage, and a decrease in driving life. On the other hand, in one embodiment of the present invention, layer 200 is a layer having a first organic compound 161_1, a second organic compound 161_2, and a metal material 161_M, and in layer 200, these materials form a composite material. In this composite material, the first organic compound 161_1 and the metal material 161_M interact to form a donor level (SOMO level or HOMO level), and donate electrons to the second organic compound 161_2. Therefore, when such a layer 200 is used as the first layer (161a, 161b) of the intermediate layer (160a, 160b), the electron injection barrier from the intermediate layer (160a, 160b) to the first electron transport layer (114a_1, 114b_1) is reduced, and electrons generated in the intermediate layer (160a, 160b) can be smoothly injected and transported to the first electron transport layer (114a_1, 114b_1). Furthermore, when such a layer 200 is used as the electron injection layer (115, 115a, 115b), the electron injection barrier from the second electrode 102 to the organic compound layer (103a, 103b) is reduced, and electrons injected from the second electrode 102 can be smoothly injected and transported to the light-emitting layer (113a, 113b). Furthermore, it is preferable because it is possible to form a layer that is resistant to oxygen and water in the atmosphere, as well as water and chemicals used in the lithography process. Therefore, one aspect of the present invention can provide a display device using a light-emitting device that has excellent moisture resistance, water resistance, oxygen resistance, and chemical resistance, a low driving voltage, and good luminous efficiency.

[0218] Furthermore, it is more preferable that the metallic material 161_M contains a metallic element belonging to an odd-numbered group in the periodic table. This configuration is preferable because, when the first organic compound 161_1 and the metallic material 161_M interact, the stabilization energy becomes lower and more stable, and the donor level (SOMO level or HOMO level) that is formed can be a high-energy level.

[0219] It is preferable to select and use organic compounds that can form a charge transfer complex when combined with a metal material 161_M for the first organic compound 161_1 and the second organic compound 161_2. A charge transfer complex is a state consisting of two or more substances, and is formed by the transfer of charge from one substance to another through interaction. When the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are in a combination that can form a charge transfer complex, the first organic compound 161_1 is more likely to function as an electron donor to the second organic compound 161_2 via the metal material 161_M. In other words, by selecting and using organic compounds that can form a charge transfer complex when combined with a metal material 161_M for the first organic compound 161_1 and the second organic compound 161_2, it is possible to facilitate electron donation to the second organic compound 161_2 from the donor level formed by the first organic compound 161_1 and the metal material 161_M.

[0220] When a charge-transfer complex is formed, a new absorption band is observed that is different from that of the individual substances forming the complex. Therefore, by preparing a film by mixing each substance and measuring the absorption spectrum of that film, it is possible to determine whether the combination of substances is capable of forming a charge-transfer complex.

[0221] For example, a first mixed film is prepared containing a first organic compound 161_1, a second organic compound 161_2, and a metal material 161_M, and a second mixed film is prepared containing either the first organic compound 161_1 or the second organic compound 161_2, and a metal material 161_M, and having a film thickness equivalent to that of the first mixed film, for example, with a difference of 10% or less from the film thickness of the first mixed film. The absorption spectra are then measured. In this case, it is preferable that the absorption spectrum of the first mixed layer has a wavelength region with greater absorption intensity than the absorption spectrum of the second mixed layer. In such a case, it can be said that the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that readily interacts with each other. Furthermore, it can be said that the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that forms a charge transfer complex.

[0222] Furthermore, it is more preferable that the absorption spectrum of the first mixed film has a wavelength region where the absorption intensity is greater than that of the absorption spectrum of the second mixed film, in a region with wavelengths longer than the absorption edge on the long-wavelength side of the absorption spectrum of either the first organic compound 161_1 or the second organic compound 161_2 of the second mixed film. In such a case, it becomes clearer that a new absorption band different from that of the individual substances forming the charge transfer complex has been created in the first mixed film, making it easier to determine that the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that forms a charge transfer complex.

[0223] Furthermore, for example, a first mixed film containing a first organic compound 161_1, a second organic compound 161_2, and a metal material 161_M is prepared, and a third mixed film containing the first organic compound 161_1 and the metal material 161_M, and having a film thickness equivalent to that of the first mixed film, for example, with a difference of 10% or less from the film thickness of the first mixed film, is prepared, and its absorption spectrum is measured. At this time, it is preferable that the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the third mixed film. In addition, a fourth mixed film containing the second organic compound 161_2 and the metal material 161_M, and having a film thickness equivalent to that of the first mixed film, for example, with a difference of 10% or less from the film thickness of the first mixed film, is prepared. At this time, it is preferable that the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film. In such cases, the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that readily interacts with each other. Furthermore, the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that forms a charge-transfer complex.

[0224] Furthermore, one aspect of the present invention is a light-emitting device using the above-described configuration, wherein the absorption spectrum of the first mixed film has a wavelength region where the absorption intensity is greater than that of the third mixed film in a region with wavelengths longer than the long-wavelength absorption edge of the absorption spectrum of the film having the first organic compound 161_1, and the absorption spectrum of the first mixed film has a wavelength region where the absorption intensity is greater than that of the fourth mixed film in a region with wavelengths longer than the long-wavelength absorption edge of the absorption spectrum of the film having the second organic compound 161_2. In such a case, it becomes clearer that a new absorption band different from that of the individual substances forming the charge transfer complex has been generated in the first mixed film, making it easier to determine that the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are a combination that forms a charge transfer complex.

[0225] The absorption edge on the long-wavelength side of the absorption spectrum can be calculated by drawing a tangent line at the point where the absolute value of the slope on the long-wavelength side of the peak (or shoulder peak) observed at the longest wavelength of the absorption spectrum is maximum, and then finding the intersection of that tangent line with the horizontal axis or baseline.

[0226] The intensity of the absorption spectrum depends on the film thickness of the sample used for measurement. Therefore, when comparing the absorption spectrum of the first mixed film with that of the second, third, or fourth mixed film, it is preferable that the second, third, or fourth mixed film has a film thickness equivalent to that of the first mixed film, for example, a difference of 10% or less from the film thickness of the first mixed film, more preferably 7% or less, even more preferably 5% or less, and most preferably 3% or less. This makes it possible to more accurately determine whether or not a combination of materials can form a charge transfer complex.

[0227] Furthermore, it is preferable to use an organic compound for the first organic compound 161_1 that has a higher LUMO (Lowest Unoccupied Molecular Orbital) level than the second organic compound 161_2. This facilitates interaction between the first organic compound 161_1 and the second organic compound 161_2, and also facilitates electron donation from the donor level formed between the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2. It is also preferable to use an organic compound for the first organic compound 161_1 that has a LUMO level 0.05 eV or higher than the second organic compound 161_2. Alternatively, it is preferable to use an organic compound for the first organic compound 161_1 that has a LUMO level that is preferably 0.1 eV or higher, and more preferably 0.2 eV or higher, than that of the second organic compound 161_2.

[0228] For example, the organic compound used as the first organic compound 161_1 preferably has a LUMO level of -3.0 eV to -2.0 eV, and more preferably -2.7 eV to -2.0 eV. This makes it easier to donate electrons from the donor level formed by the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2. Furthermore, the organic compound used as the second organic compound 161_2 preferably has a LUMO level of -3.0 eV to -2.0 eV, and more preferably -3.0 eV to -2.5 eV. This enhances the electron transport properties of the second organic compound 161_2.

[0229] It is preferable to use an organic compound for the first organic compound 161_1 that has a higher HOMO level than the second organic compound 161_2. This facilitates interaction between the first organic compound 161_1 and the second organic compound 161_2, and further facilitates electron donation from the donor level formed by the first organic compound 161_1 and the metal material 161_M to the second organic compound 161_2. Alternatively, it is preferable to use an organic compound for the first organic compound 161_1 that has a HOMO level 0.05 eV or higher than the second organic compound 161_2. Or, it is preferable to use an organic compound for the first organic compound 161_1 that has a HOMO level preferably 0.1 eV or higher, and more preferably 0.2 eV or higher than the second organic compound 161_2.

[0230] The HOMO and LUMO levels of organic compounds are generally estimated by methods such as cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, and inverse photoelectron spectroscopy. When comparing values ​​between different compounds, it is preferable to use values ​​estimated by the same measurement method.

[0231] Furthermore, it is preferable to use electron-transporting organic compounds for the first organic compound 161_1 and the second organic compound 161_2, respectively. Examples of electron-transporting organic compounds include organic compounds having heteroaromatic rings. Specifically, π-electron-deficient heteroaromatic rings such as pyridine rings, pyrazine rings, pyrimidine rings, pyridazine rings, triazine rings, imidazole rings, pyrazole rings, oxazole rings, thiazole rings, triazole rings, and condensed rings containing these are preferred because they are electrochemically stable and have high electron-transporting properties.

[0232] Each of the above-mentioned heteroaromatic rings contains a nitrogen atom with a lone pair of electrons, making them preferable because they readily interact with the metallic material 161_M.

[0233] Furthermore, it is preferable to use an organic compound having an electron-donating group for the first organic compound 161_1. By using an organic compound having an electron-donating group for the first organic compound 161_1, the first organic compound 161_1 and the metal material 161_M become more likely to interact. In addition, electrons are more likely to be donated to the second organic compound 161_2 from the donor level formed by the first organic compound 161_1 and the metal material 161_M.

[0234] Details of the materials that can be used in the metallic material 161_M, the first organic compound 161_1, and the second organic compound 161_2 will be described later.

[0235] <Analysis of the interaction between each organic compound and the metal material using quantum chemical calculations> Here, we performed a quantum chemical calculation analysis of the interaction between the metal material 161_M, the first organic compound 161_1, and the second organic compound 161_2.

[0236] <Estimation of the interaction between each organic compound and the metallic material> First, quantum chemical calculations were performed to analyze the spin density and electrostatic potential (ESP) when the first organic compound 161_1, the second organic compound 161_2, and the metallic material 161_M interacted. For the calculations, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) was used as the first organic compound 161_1, 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen) or 2,2'-([2,2'-bipyridine]-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as 6,6'(P-Bqn)2BPy) was used as the second organic compound 161_2, and silver (Ag) was used as the metal material 161_M. The structural formulas of Pyrrd-Phen, NBPhen, and 6,6'(P-Bqn)2BPy are shown below. Note that the phenanthroline rings in the structural formulas of Pyrrd-Phen and NBPhen are numbered by position.

[0237]

[0238] Gaussian09 was used as the quantum chemistry calculation program. The calculations were performed using an HPE SGI8600 to determine the most stable ground state structure of each organic compound and composite material using density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as basis sets, and B3LYP was used as the functional. The total energy of the DFT is expressed as the sum of the potential energy, the electrostatic energy between electrons, the kinetic energy of electrons, and the exchange-correlation energy, which encompasses all complex electron-electron interactions. Because the DFT approximates the exchange-correlation interaction with a functional (meaning a function of a function) of the one-electron potential expressed in terms of electron density, the calculation is highly accurate.

[0239] Figures 7A to 7C show the analysis results of the spin density distribution in the ground state of composite materials of the first organic compound (Pyrrd-Phen) and the metal material (Ag), the second organic compound (NBPhen) and the metal material (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metal material (Ag), when Pyrrd-Phen is used as the first organic compound 161_1, NBPhen is used as the second organic compound 161_2, and Ag is used as the metal material 161_M. The spheres in the figures represent atoms constituting the compounds, and the cloud-like substances surrounding the atoms have a density value of 0.003 e / a in atomic units. ０ ３ (e is the elementary charge (1e = 1.60218 × 10) −１９ C) and a ０ The Bohr radius is (1a ０ = 5.29177 × 10 −１１ This shows the spin density distribution when m is represented, indicating the localization of the doublet ground state in the compound. Note that the ground state of Pyrrd-Phen and the ground state of NBPhen are singlet ground states, so no spin density distribution is observed.

[0240] Figure 7A shows the analysis results of the spin density distribution in the ground state of a composite material of the first organic compound (Pyrrd-Phen) and a metallic material (Ag). In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), the first organic compound (Pyrrd-Phen) and the metallic material (Ag) interact, and the metallic material (Ag) is stabilized by coordinating to the nitrogen atoms (N) at positions 1 and 10, which have lone pairs of electrons in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen). Therefore, as shown in Figure 7A, it can be seen that some of the spin originating from the unpaired electrons of Ag is distributed to a part of the 1,10-phenanthroline ring of Pyrrd-Phen, in particular to the nitrogen atoms (N) at positions 1 and 10, which have lone pairs of electrons. However, because the interaction is weak, most of the spin density is distributed in Ag. Hereinafter, the nitrogen atoms (N) at positions 1 and 10 in the 1,10-phenanthroline ring that have lone pairs of electrons may be referred to as N1 and N10.

[0241] Figure 7B shows the analysis results of the spin density distribution in the ground state of a composite material of a second organic compound (NBPhen) and a metallic material (Ag). In the doublet ground state of the composite material of a second organic compound (NBPhen) and a metallic material (Ag), the second organic compound (NBPhen) and the metallic material (Ag) interact, and the metallic material (Ag) is stabilized by coordinating to N1 and N10 of the second organic compound (NBPhen). Therefore, as shown in Figure 7B, it can be seen that some of the spin originating from the unpaired electrons of Ag is distributed to a part of the 1,10-phenanthroline ring of NBPhen, especially N1 and N10. However, because the interaction is weak, most of the spin density is distributed in Ag.

[0242] Figure 7C shows the analysis results of the spin density distribution in the ground state of a composite material consisting of a first organic compound (Pyrrd-Phen), a second organic compound (NBPhen), and a metallic material (Ag). In the doublet ground state of the composite material consisting of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag), the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metallic material (Ag) interact, and the metallic material (Ag) is stabilized by coordinating to N1 and N10 of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen). Therefore, as shown in Figure 7C, it can be seen that the spin originating from the unpaired electrons of Ag is localized in NBPhen. Furthermore, no spin density distribution is observed in Ag. This indicates that the interaction between Pyrrd-Phen, NBPhen, and Ag puts NBPhen into a radical anion state.

[0243] Figure 8 shows the analysis results of the spin density distribution in the ground state of a composite material of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal material (Ag), when Ag is used as the metal material 161_M, Pyrrd-Phen is used as the first organic compound 161_1, and 6,6'(P-Bqn)2BPy is used as the second organic compound 161_2. The spheres in the figure represent atoms constituting the compound, and the cloud-like structures surrounding the atoms have a density threshold (isovalue) of 0.0004e / a ０ ３ This shows the spin density distribution and indicates the localization of the doublet ground state in the compound. Note that the ground state of Pyrrd-Phen and the ground state of 6,6'(P-Bqn)2BPy are singlet ground states, so no spin density distribution is observed for them.

[0244] In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag), the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag) interact with each other, and the metal material (Ag) is stabilized by coordinating to N1 and N10 of the first organic compound (Pyrrd-Phen), and to the nitrogen atoms having lone pairs in the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy). Therefore, as shown in FIG. 8, it is found that the spin derived from the unpaired electron possessed by Ag is localized in 6,6'(P-Bqn)2BPy. In addition, no spin density distribution is observed in Ag. This indicates that the second organic compound (6,6'(P-Bqn)2BPy) is in a radical anion state due to the interaction of Pyrrd-Phen, 6,6'(P-Bqn)2BPy, and Ag.

[0245] Next, using Ag as the metal material 161_M, Pyrrd-Phen as the first organic compound 161_1, and NBPhen as the second organic compound 161_2, the analysis results of the electrostatic potential maps in the ground state of the first organic compound (Pyrrd-Phen), the ground state of the second organic compound (NBPhen), the ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal material (Ag), the ground state of the composite material of the second organic compound (NBPhen) and the metal material (Ag), and the ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metal material (Ag) are shown in FIG. 9A, FIG. 9B, FIG. 10A, FIG. 10B, and FIG. 10C, respectively. The spheres in the figures represent the atoms constituting the compound, and the cloud-like substances present around the atoms have a density value of 0.003 e / a in the atomic unit system ０ ３This shows the ESP in the electron density distribution. ESP is the interaction energy between a positive point charge with a unit electric charge and the electron distribution of a molecule. The electrostatic potential map represents the ESP on an isoelectron density surface using color. Regions with negative ESP are represented in red, and regions with positive ESP are represented in blue. Atoms in the negative ESP region have a negative charge, and atoms in the positive ESP region have a positive charge. However, since Figures 9 and 10 are grayscale images, to show the regions with negative ESP and positive ESP, the dark red areas (i.e., regions with negative ESP) are enclosed by thick dotted lines, and the dark blue areas (i.e., regions with positive ESP) are enclosed by thin dashed lines.

[0246] Figure 9A shows the results of the electrostatic potential map analysis in the ground state of the first organic compound (Pyrrd-Phen). From Figure 9A, it can be seen that the ESP around N1 and N10 is negative in the singlet ground state of the first organic compound (Pyrrd-Phen). Also, the Mulliken partial charge of N1 and N10 was negative, -0.29e in atomic units. From these findings, it can be seen that N1 and N10 have negative partial charges in the singlet ground state of the first organic compound (Pyrrd-Phen).

[0247] Figure 9B shows the results of the electrostatic potential map analysis in the ground state of the second organic compound (NBPhen). From Figure 9B, it can be seen that the ESP around N1 and N10 is negative in the singlet ground state of the second organic compound (NBPhen). In addition, the Mulliken partial charge of both N1 and N10 was negative, at -0.34e in atomic units. From these findings, it can be seen that N1 and N10 have negative partial charges in the singlet ground state of the second organic compound (NBPhen).

[0248] Figure 10A shows the results of the electrostatic potential map analysis in the ground state of a composite material of the first organic compound (Pyrrd-Phen) and a metallic material (Ag). In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), the first organic compound (Pyrrd-Phen) and the metallic material (Ag) interact, and the metallic material (Ag) is stabilized by coordinating to N1 and N10 of the first organic compound (Pyrrd-Phen). As a result, as shown in Figure 10A, it can be seen that the ESP around N1, N10 of Pyrrd-Phen and Ag is negative. In addition, the Mulliken partial charge of N1 and N10 is negative, at -0.37e in atomic units. Also, the Mulliken partial charge of Ag is negative, at -0.18e in atomic units. From these findings, it can be seen that in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metallic material (Ag), N1, N10, and Ag have negative partial charges.

[0249] Figure 10B shows the results of the electrostatic potential map analysis in the ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag). In the doublet ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag), the second organic compound (NBPhen) and the metallic material (Ag) interact, and the metallic material (Ag) stabilizes by coordinating to N1 and N10 of the second organic compound (NBPhen). As a result, as shown in Figure 10B, it can be seen that the ESP around N1, N10 of NBPhen and Ag is negative. Furthermore, the Mulliken partial charges of N1 and N10 are -0.45e and -0.39e, respectively in atomic units, and the Mulliken partial charge of the metallic material (Ag) is -0.06e, both of which are negative in atomic units. From these findings, it can be seen that in the doublet ground state of the composite material of the second organic compound (NBPhen) and the metallic material (Ag), N1, N10, and Ag have negative partial charges.

[0250] Figure 10C shows the results of the electrostatic potential map analysis in the ground state of a composite material of a first organic compound (Pyrrd-Phen), a second organic compound (NBPhen), and a metal material (Ag). In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metal material (Ag), the first organic compound (Pyrrd-Phen), the second organic compound (NBPhen), and the metal material (Ag) interact, and the metal material (Ag) is stabilized by coordinating to N1 and N10 of the first organic compound (Pyrrd-Phen) and N1 and N10 of the second organic compound (NBPhen). As a result, as shown in Figure 10C, it can be seen that positive ESP is mainly distributed around Ag and Pyrrd-Phen, and negative ESP is mainly distributed around NBPhen. Furthermore, it can be seen that the ESP around N1 and N10 of NBPhen is negative, while the ESP of Ag is positive. In addition, the Mulliken partial charge of N1 and N10 of NBPhen is negative at -0.52e in atomic units, while the Mulliken partial charge of Ag is positive at 0.39e in atomic units. From these findings, it can be seen that the charge of Ag atoms is distributed at N1 and N10 of NBPhen.

[0251] Next, Figure 11 shows the results of the electrostatic potential map analysis in the ground state of a composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag), when Ag is used as the metal material 161_M, Pyrrd-Phen is used as the first organic compound 161_1, and 6,6'(P-Bqn)2BPy is used as the second organic compound 161_2. The spheres in the figure represent atoms constituting the compound, and the cloud-like substances surrounding the atoms have a density threshold (isovalue) of 0.0004 [electrons / au ３ This shows the ESP in the electron density distribution when ]. In Figure 11, to show the negative ESP region and the positive ESP region, the dark red area (i.e., the negative ESP region) is enclosed by a thick dotted line, and the dark blue area (i.e., the positive ESP region) is enclosed by a thin dashed line.

[0252] In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag), the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal material (Ag) interact, and the metal material (Ag) is stabilized by coordinating to N1 and N10 of the first organic compound (Pyrrd-Phen) and to the nitrogen atoms with lone pairs of electrons in the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy). As a result, as shown in Figure 11, positive ESP is mainly distributed in Ag and Pyrrd-Phen, and negative ESP is mainly distributed in 6,6'(P-Bqn)2BPy. Furthermore, it can be seen that the ESP of the nitrogen atom with a lone pair of electrons in the pyridine ring and benzo[h]quinazoline ring of 6,6'(P-Bqn)2BPy is negative, while the ESP of Ag is positive. The Mulliken partial charge of the Ag atom in question was +0.372e in atomic units.

[0253] From the above, it can be seen that the first organic compound 161_1 and the metal material 161_M interact to form an electron donor, and further function as an electron donor for the second organic compound 161_2 which has electron transport properties. In one aspect of the present invention, by using the composite material of this combination in at least one of the intermediate layer and the electron injection layer, it is possible to form at least one of the intermediate layer and the electron injection layer that has good electron injection characteristics and is resistant to oxygen and water in the atmosphere, as well as water and chemicals used in the lithography process, thereby reducing the driving voltage and obtaining a display device using a light-emitting device with high luminous efficiency.

[0254] <Estimation of SOMO Level or Stabilization Energy> Next, quantum chemical calculations were used to estimate the stabilization energy when the metallic material 161_M, the first organic compound 161_1, and the second organic compound 161_2 interact, and the SOMO level or HOMO level formed at that time. For the calculations, silver (Ag), aluminum (Al), copper (Cu), or indium (In) was used as the metallic material 161_M, Pyrrd-Phen was used as the first organic compound 161_1, and 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), NBPhen, 6,6'(P-Bqn)2BPy, 4',4''''-(1,4-phenylene)bis(2,2':6',2''-terpyridine) (abbreviation: tPy2P), or 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn) was used as the second organic compound 161_2.

[0255] The structural formulas for Pyrrd-Phen, mPPhen2P, NBPhen, 6,6'(P-Bqn)2BPy, tPy2P, and 2Py3TZn are shown below. Note that 6,6'(P-Bqn)2BPy, tPy2P, and 2Py3TZn are organic compounds having two or more heteroaromatic rings, which are bonded or condensed with each other, resulting in a total of three or more heteroatoms. On the other hand, NBPhen is an organic compound having two or more heteroaromatic rings, which are bonded or condensed with each other, but with a total of less than three heteroatoms.

[0256]

[0257] Gaussian 09 was used as the quantum chemistry calculation program. The calculations were performed using an SGI 8600 manufactured by HPE. First, the most stable structures in the ground state of each of the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M, as well as the composite material of the first organic compound 161_1 and the metal material 161_M, the composite material of the second organic compound 161_2 and the metal material 161_M, and the composite material of the first organic compound 161_1, the second organic compound 161_2 and the metal material 161_M, were calculated by the density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as the functional. Next, the stabilization energy was calculated from the difference between the total energy of the composite material of the organic compound and the metal element, and the sum of the total energy of the organic compound and the total energy of the metal element. That is, (stabilization energy) = (total energy of the composite material of the organic compound and the metal element) - (total energy of the organic compound) - (total energy of the metal element).

[0258] The results of calculating the stabilization energy of the composite material of the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M are shown in each table.

[0259] Table 1 shows the calculation results of the composite material using Pyrrd-Phen as the first organic compound 161_1, mPPhen2P as the second organic compound 161_2, and Ag as the metal material 161_M. Note that Table 1 shows the stabilization energy of the composite material of Ag and Pyrrd-Phen, and the stabilization energy of the composite material of mPPhen2P and Ag.

[0260]

[0261] From Table 1, it is found that the stabilization energies of the composite material of Pyrrd-Phen and Ag and the composite material of mPPhen2P and Ag are negative values, and when either Pyrrd-Phen or mPPhen2P interacts with Ag, the system is energetically stable compared to the case where these do not interact. However, the absolute value of the stabilization energy is small, and it is understood that the interaction between either Pyrrd-Phen or mPPhen2P and Ag is weak.

[0262] On the other hand, from Table 1, it is found that the stabilization energy of the composite material of Pyrrd-Phen, mPPhen2P and Ag is smaller than the stabilization energy of the composite material of Pyrrd-Phen and Ag and the stabilization energy of the composite material of mPPhen2P and Ag, and is energetically stable. As described above, the stabilization energy of the composite material of the metal material 161_M, the first organic compound 161_1, and the second organic compound 161_2 is preferably -0.50 eV or less, and more preferably -1.0 eV or less, -2.0 eV or less, -3.0 eV or less, and -4.0 eV or less.

[0263] Next, Table 2 shows the calculation results of composite materials using Pyrrd-Phen as the first organic compound 161_1, mPPhen2P as the second organic compound 161_2, and a metal belonging to an odd-numbered group (Group 3, Group 5, Group 7, Group 9, Group 11, or Group 13), specifically Al, Ag, Cu, or In, as the metal material 161_M.

[0264]

[0265] Table 2 shows that the stabilization energy of the composite material of Pyrrd-Phen, mPPhen2P, and Al is -4.0 eV or less, the stabilization energy of the composite material of Pyrrd-Phen, mPPhen2P, and Cu is -3.0 eV or less, and the stabilization energy of the composite material of Pyrrd-Phen, mPPhen2P, and Ag and the composite material of Pyrrd-Phen, mPPhen2P, and In is -1.0 eV or less. Thus, by using metal elements belonging to odd-numbered groups, the stabilization energies of the composite materials of the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M become -1.0 eV or less, -3.0 eV or less, and -4.0 eV or less, respectively, making them more energetically stable and preferable. Furthermore, the calculated SOMO levels of these composite materials are higher than those of Pyrrd-Phen (-5.65 eV) and mPPhen2P (-5.88 eV). A higher SOMO level is preferable because it allows for the creation of layers with superior electron injection properties when the composite material is used as an intermediate layer and an electron injection layer.

[0266] Next, calculations were performed on composite materials using Pyrrd-Phen as the first organic compound 161_1, 6,6'(P-Bqn)2BPy, tPy2P, 2Py3Tzn, or NBPhen as the second organic compound 161_2, and metals belonging to groups 11 and 13, specifically Ag, Al, or In, as the metallic material 161_M.

[0267] Table 3 shows the calculation results when Pyrrd-Phen is used as the first organic compound 161_1, 6,6'(P-Bqn)2BPy or NBPhen is used as the second organic compound 161_2, and Ag is used as the metallic material 161_M. Table 3 also shows the calculation results for composite materials using Pyrrd-Phen and Ag, composite materials using 6,6'(P-Bqn)2BPy and Ag, and composite materials using NBPhen and Ag.

[0268]

[0269] Table 4 shows the LUMO and HOMO levels for Pyrrd-Phen, 6,6'(P-Bqn)2BPy, tPy2P, 2Py3Tzn, and NBPhen. Note that the energy levels of the HOMO and LUMO levels in the table are calculated values ​​and may differ in absolute value from experimentally measured values.

[0270]

[0271] Table 3 shows that the stabilization energy of the composite material of Pyrrd-Phen, 6,6'(P-Bqn)2BPy, and Ag is negative and has a large absolute value. This indicates that when Pyrrd-Phen, 6,6'(P-Bqn)2BPy, and Ag interact, they are energetically more stable than when they do not interact. Furthermore, Tables 3 and 4 show that the SOMO level of this composite material is higher than the HOMO levels of Pyrrd-Phen and 6,6'(P-Bqn)2BPy, respectively, and the energy difference with their respective LUMO levels is small. Therefore, using this composite material as an intermediate layer or electron injection layer is preferable because it can result in a layer with excellent electron injection properties.

[0272] Furthermore, as shown in Table 3, the composite material of Pyrrd-Phen, NB-Phen, and Ag also has a negative stabilization energy, indicating that when Pyrrd-Phen, NB-Phen, and Ag interact, the energy is more stable compared to when they do not interact.

[0273] Furthermore, the composite material of 6,6'(P-Bqn)2BPy and Ag has a low SOMO level of -2.86 eV. On the other hand, the composite material containing 6,6'(P-Bqn)2BPy, Pyrrd-Phen, and Ag has a higher SOMO level of -2.35 eV, resulting in superior electron injection performance. In addition, the composite material of 6,6'(P-Bqn)2BPy and Ag has a stabilization energy of -0.73 eV, while the composite material of 6,6'(P-Bqn)2BPy, Pyrrd-Phen, and Ag is more stable with a stabilization energy of -1.29 eV.

[0274] Furthermore, the composite material of Ag and NBPhen has a low SOMO level of -3.26 eV. On the other hand, the composite material containing Ag, NBPhen, and Pyrrd-Phen has a high SOMO level of -2.50 eV, resulting in superior electron injection. In addition, the composite material of Ag and NBPhen has a stabilization energy of -0.23 eV, while the composite material of Ag, NBPhen, and Pyrrd-Phen has a stabilization energy of -1.26 eV, making it more stable.

[0275] Table 5 also shows the calculation results when Pyrrd-Phen is used as the first organic compound 161_1, 6,6'(P-Bqn)2BPy, tPy2P, 2Py3Tzn, or NBPhen is used as the second organic compound 161_2, and In or Al is used as the metallic material 161_M.

[0276]

[0277] Table 5 shows that the stabilization energies of composite materials consisting of In or Al, Pyrrd-Phen, and tPy2P, 2Py3TZn, or NBPhen are negative and have large absolute values.

[0278] Thus, the stabilization energy of the composite material of metals belonging to Groups 11 and 13, the first organic compound 161_1, and the second organic compound 161_2 is stable and preferable. Furthermore, the SOMO level formed at this time is high and has excellent electron injection properties, which is also preferable.

[0279] Based on the above calculation results, the composite material using the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M is stable, has excellent electron injection properties, and is suitable for use as an intermediate layer or electron injection layer.

[0280] Considering the manufacturing process of light-emitting devices, the organic compound layer, particularly the intermediate layer, of a light-emitting device is generally formed by vacuum deposition. In this case, it is preferable to use a material that can be easily subjected to vacuum deposition, i.e., a material with a low melting point. Metals of Group 11 and Group 13 elements have low melting points and are therefore suitable for vacuum deposition. Furthermore, metals of Group 11 and Group 13 elements are preferable because they are stable in oxygen and water in the atmosphere. In addition, vacuum deposition is preferable because it allows for easy mixing of metal atoms and organic compounds.

[0281] Furthermore, Ag, Al, and In can each be used as cathode materials. Using the same material for both the intermediate layer and the cathode is preferable because it simplifies the fabrication of the light-emitting device. It also reduces the manufacturing cost of the light-emitting device.

[0282] 《Analysis of composite materials of metals and organic compounds》 At least one of the intermediate layer and the electron injection layer to which layer 200 is applied in the light-emitting device can be measured as a composite material in which the first organic compound 161_1, the second organic compound 161_2, and the metal material 161_M have interacted.

[0283] Specifically, a film is prepared using the same mixing ratio as the intermediate layer used in the light-emitting device, and this film is measured using mass spectrometry methods such as time-of-flight secondary ion mass spectrometry (ToF-SIMS), laser desorption / ionization mass spectrometry (LDI-MS), and matrix-assisted laser desorption / ionization mass spectrometry (MALDI-MS).

[0284] As a result of the mass spectrometry, if the mass number of the first organic compound 161_1 is M1, the mass number of the second organic compound 161_2 is M2, and the mass number of the metal material 161_M is M3, then positive ions with a mass-to-charge ratio m / z of M1 + M2 + M3 or M1 + M2 + M3 + 1 can be detected. When measuring positive ions using these mass spectrometry methods, ions originating from compounds contained in the membrane, substituents detached from the compounds, compounds from which substituents have been detached, and aggregates thereof are detected. Therefore, for example, if the mass number of the metal detached from the metal compound is 31, then positive ions with a m / z of M1 + M2 + 31 or M1 + M2 + 31 + 1 can be detected.

[0285] Next, we will describe the details of the materials that can be used in the metal material 161_M, the first organic compound 161_1, and the second organic compound 161_2.

[0286] <Metallic Material 161_M> As described above, metallic material 161_M is either a metal or a metallic compound, or both. Furthermore, it is preferable that either one or both of the metal and the metallic compound have at least one element selected from the metallic elements of Groups 3 to 14 of the periodic table.

[0287] As metallic elements from groups 3 to 11 of the periodic table (i.e., transition elements), the following can be used: Group 3 elements including lanthanides such as yttrium (Y), europium (Eu), and ytterbium (Yb); Group 4 elements such as titanium (Ti); Group 5 elements such as vanadium (V); Group 5 elements such as chromium (Cr); Group 7 elements such as manganese (Mn); Group 8 elements such as iron (Fe); Group 9 elements such as cobalt (Co); Group 10 elements such as nickel (Ni) and platinum (Pt); and Group 11 elements such as copper (Cu), silver (Ag), and gold (Au). Transition elements are preferred because they have low reactivity with components in the atmosphere such as water and oxygen.

[0288] As metallic elements from groups 12 to 14, group 12 elements such as zinc (Zn), earth metals such as aluminum (Al) and indium (In) (group 13 elements), and group 14 elements such as tin (Sn) can be used.

[0289] Among the above, metal elements belonging to odd-numbered groups (Group 3, Group 5, Group 7, Group 9, Group 11, and Group 13) in the periodic table are more preferable. Among these metal elements, a metal material having a metal element with one electron (unpaired electron) in the outermost shell orbital is particularly preferable because it easily forms a SOMO with the first organic compound 161_1.

[0290] Further, among the above, a metal material having a metal element that has a low melting point and can be formed into a film by a vacuum deposition method is preferable because it can easily form a mixed layer with an organic compound. Specifically, for example, metals of Group 11 elements and Group 13 elements have low melting points, and thus can be suitably used for vacuum deposition. In addition, metals of Group 11 elements and Group 13 elements are preferable as they are stable to oxygen and moisture in the atmosphere.

[0291] Further, when the metal material 161_M is a metal compound, specific examples thereof include metal oxides and metal nitrides containing at least any one selected from the above metal elements.

[0292] Note that even if a metal is used as a raw material for forming the layer 200, it may be oxidized during processes such as film formation and exposure to the atmosphere, and may become a metal oxide. In such a case, the layer 200 may contain both a metal and a metal compound.

[0293] Further, the content of the metal material 161_M in the layer 200 is preferably 0.1% to 5% by volume, and more preferably 1% to 5% by volume. When the layer 200 is formed by a vacuum deposition method, adjusting the content to fall within such a range is preferable because a uniform film can be formed, and the characteristics of the light-emitting device can be improved.

[0294] For analyzing the elemental content of a film, for example, secondary ion mass spectrometry (SIMS) or X-ray photoelectron spectroscopy (XPS) can be used. XPS is suitable when the content of the target element is high (e.g., 0.5 atomic% or more, or 1 atomic% or more). On the other hand, SIMS is suitable when the content of the target element is low (e.g., 0.5 atomic% or less, or 1 atomic% or less). When comparing elemental content, it is more preferable to perform a combined analysis using both SIMS and XPS analytical methods.

[0295] <First Organic Compound 161_1> It is preferable to use an organic compound having electron-transporting properties as the first organic compound 161_1. Examples of organic compounds having electron-transporting properties include organic compounds having a heteroaromatic ring. Among heteroaromatic rings, it is even more preferable to use an organic compound having a π-electron-deficient heteroaromatic ring that is electrochemically stable and has high electron-transporting properties. Furthermore, in order for the first organic compound 161_1 to interact with the metal material 161_M and function as an electron donor for the second organic compound 161_2, it is preferable that the π-electron-deficient heteroaromatic ring has a lone pair of electrons, and it is preferable that the lone pair of electrons has electron-donating properties. That is, it is preferable that the first organic compound 161_1 has a basic π-electron-deficient heteroaromatic ring. Also, since nitrogen has high electronegativity, it readily interacts with metals. Furthermore, since nitrogen can form conjugated bonds in organic compounds, using nitrogen in the molecule, particularly in a heteroaromatic ring, can result in an organic compound with high carrier transport properties. Therefore, it is preferable that the first organic compound 161_1 has a heteroaromatic ring containing nitrogen. It is even more preferable that the heteroaromatic ring is an even-numbered ring, such as a six-membered or eight-membered ring. With this configuration, the lone pair of electrons on the nitrogen does not participate in conjugation, making it easier to interact with the metal material 161_M. In addition, it is preferable that the first organic compound 161_1 has electron transport properties in order to smoothly inject and transport electrons from the intermediate layer to the electron transport layer. Specifically, for example, it is preferable that the first organic compound 161_1 has a pyridine ring.

[0296] Furthermore, it is preferable that the first organic compound 161_1 has two or more π-electron-deficient heteroaromatic rings, and that these two or more π-electron-deficient heteroaromatic rings are bonded or condensed with each other. This stabilizes the interaction between the metal material 161_M and the first organic compound 161_1 and the second organic compound 161_2 at a bidentate or multidentate level, thus forming an intermediate layer that is less prone to degradation even after a lithography process involving exposure to air. As a result, even after a lithography process involving exposure of the EL layer to air, electrons generated in the intermediate layer can be smoothly injected and transported to the adjacent electron transport layer, suppressing the rise in driving voltage, and enabling the fabrication of a tandem-type light-emitting device with good luminescence efficiency and reliability using a lithography process. Specifically, for example, it is preferable that the first organic compound 161_1 has heteroaromatic rings containing two or more pyridine rings. Among these, organic compounds having a bipyridine skeleton are preferred because the nitrogen atom readily coordinates with the metal, making them readily interacting with the metal material 161_M.

[0297] Furthermore, the phenanthroline ring is preferred because it is rigid and highly stable. In particular, among phenanthroline rings, organic compounds having a 1,10-phenanthroline ring are preferred because the two nitrogen atoms they contain can coordinate to the metal, thus easily interacting with the metal material 161_M.

[0298] Furthermore, the first organic compound 161_1 may have a structure in which multiple phenanthroline rings are linked via single bonds or divalent groups. Specific examples of divalent groups include alkylene groups and arylene groups.

[0299] An alkylene group is a divalent group obtained by removing two hydrogen atoms from an alkane. Specific examples of alkylene groups include divalent groups that have a structure obtained by removing one more hydrogen atom from the alkyl group examples mentioned above.

[0300] An arylene group is a divalent group obtained by removing two hydrogen atoms from an aromatic hydrocarbon. A specific example is a divalent group having a structure obtained by removing one more hydrogen atom from the aryl group example mentioned above. Furthermore, arylene groups may have substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0301] Furthermore, it is preferable that the first organic compound 161_1 has electron-donating substituents. By doing so, the first organic compound 161_1 can have high HOMO and high LUMO levels, thereby increasing the energy difference between the LUMO level of the first organic compound 161_1 and the LUMO level of the second organic compound 161_2. When the metal material 161_M, the first organic compound 161_1, and the second organic compound 161_2 interact, the composite material formed by this interaction can be made more stable, and an intermediate layer that is less prone to degradation even after a lithography process involving exposure to air can be formed. As a result, even after a lithography process involving exposure of the EL layer to air, electrons generated in the intermediate layer can be smoothly injected and transported to the adjacent electron transport layer, suppressing the rise in driving voltage, and making it possible to fabricate a tandem type light-emitting device with good luminescence efficiency and reliability using a lithography process.

[0302] In particular, among phenanthroline rings, organic compounds having a 1,10-phenanthroline ring are preferred because the two nitrogen atoms they contain can coordinate to the metal, thus easily interacting with the metal material 161_M.

[0303] Furthermore, it is more preferable to use an organic compound having a phenanthroline ring with an electron-donating group as the first organic compound 161_1. In particular, by introducing an electron-donating group to the 1,10-phenanthroline ring, the electron density of the phenanthroline ring can be increased, thereby improving the efficiency of interaction with the metal material 161_M. Moreover, it is preferable to have an electron-donating group at least one of the 4th and 7th positions of the 1,10-phenanthroline ring. By introducing electron-donating groups to the 4th and 7th positions, the electron density of the nitrogen atoms at the 1st and 10th positions in the para position can be increased. In addition, it is possible to increase the electron density around the nitrogen atoms at the 1st and 10th positions while avoiding sterically crowded conditions. Therefore, it is preferable as it facilitates interaction with the metal material 161_M.

[0304] Furthermore, if the first organic compound 161_1 has high basicity, it becomes easier for the first organic compound 161_1 to interact with holes. Therefore, the hole transport performance in the first layer 161a using the first organic compound 161_1 can be significantly reduced. Consequently, it is possible to prevent holes from being transported from the first layer 161a to the second layer 162a, which is preferable because it allows for the creation of an efficient light-emitting device. Specifically, it is preferable that the acid dissociation constant pKa of the first organic compound 161_1 is 8 or higher, more preferably 10 or higher, and even more preferably 12 or higher.

[0305] Specific examples of electron-donating groups include alkyl groups, alkoxy groups, aryloxy groups, alkylamino groups, arylamino groups, and heterocyclic amino groups. However, the electron-donating groups that are preferable to introduce into the phenanthroline ring are not limited to these. Any group that can increase the electron density of the phenanthroline ring when introduced into it can be used as an electron-donating group. Furthermore, the electron-donating group may be introduced into the phenanthroline ring via an arylene group such as a phenylene group, and the p-phenylene group is preferred as the arylene group.

[0306] Alkyl alkyl groups are alkanes (C ｎ H ２ｎ＋２This represents a monovalent group obtained by removing one hydrogen atom from a alkyl group. Specific examples of alkyl groups include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, neohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, etc.

[0307] An alkoxy group is a monovalent group in which an alkyl group is bonded to an oxygen atom. Specific examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentyloxy, isopentyloxy, sec-pentyloxy, tert-pentyloxy, neopentyloxy, n-hexyloxy, isohexyloxy, sec-hexyloxy, tert-hexyloxy, and neohexyloxy.

[0308] An aryloxy group refers to a monovalent group in which an aryl group is bonded to an oxygen atom. An aryl group, in general, refers to a monovalent group obtained by removing one hydrogen atom from one of the carbon atoms forming the ring of a monocyclic or polycyclic aromatic compound. Specific examples of aryloxy groups include phenoxy, o-tolyloxy, m-tolyloxy, p-tolyloxy, mesityloxy, o-biphenyloxy, m-biphenyloxy, p-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, and 2-fluorenyloxy. Furthermore, aryloxy groups may have substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0309] An alkylamino group is a monovalent group obtained by removing one hydrogen atom from the nitrogen atom of a primary or secondary amine, in which one or two alkyl groups are bonded to the nitrogen atom. Specific examples of alkylamino groups include dimethylamino group and diethylamino group.

[0310] An arylamino group is a monovalent group obtained by removing one hydrogen atom from the nitrogen atom of a primary or secondary amine, in which one or two aryl groups are bonded to the nitrogen atom. Specific examples of arylamino groups include diphenylamino group, bis(α-naphthyl)amino group, and bis(m-tolyl)amino group. Furthermore, arylamino groups may have substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0311] Furthermore, an amino group in which both an alkyl group and an aryl group are bonded to a nitrogen atom can be described as either an alkylamino group or an arylamino group. Specific examples of such amino groups include, for instance, the N-methyl-N-phenylamino group.

[0312] A heterocyclic amino group refers to a monovalent group obtained by removing one hydrogen atom from one of the nitrogen atoms forming the ring of a heterocyclic amine. Here, a heterocyclic amine refers to a monocyclic or polycyclic heterocyclic compound in which at least one of the ring-forming atoms is a nitrogen atom bonded to a hydrogen atom. Specific examples of heterocyclic amino groups include the groups represented by the following structural formulas (R-1) to (R-27). Heterocyclic amino groups may also have substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0313]

[0314] Furthermore, when a heterocyclic amino group is aromatic, the lone pair of electrons on the nitrogen atom contributes to the aromaticity, which can reduce the electron-donating ability to the phenanthroline ring compared to cases where the lone pair of electrons on the nitrogen atom does not contribute to the aromaticity. Therefore, among the heterocyclic amino groups mentioned above, heterocyclic amino groups in which the lone pair of electrons on the nitrogen atom does not contribute to the aromaticity are more preferred. Specifically, the groups represented by structural formulas (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17), (R-18), or (R-22) are more preferred as electron-donating groups. Among these, the groups represented by structural formulas (R-3), (R-4), (R-8), or (R-22) are preferred because they have high electron-donating ability and can further increase the electron density of the phenanthroline ring.

[0315] Furthermore, specific examples of electron-donating groups include the groups represented by the following structural formulas (R-28) and (R-29).

[0316]

[0317] The organic compound having a phenanthroline ring that can be used as the first organic compound 161_1 may have both the electron-donating group described above and other substituents. However, introducing an electron-withdrawing group (such as a cyano group or fluoro group) to the phenanthroline ring may decrease the electron density of the phenanthroline ring, making interaction with the metal material 161_M difficult, which is undesirable. In addition to the electron-donating group described above, aryl groups are specific examples of substituents that can be introduced to the phenanthroline ring. Specific examples of aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, and 2-fluorenyl groups. The aryl group may have further substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0318] Furthermore, the first organic compound 161_1 may have a structure in which multiple phenanthroline rings are linked via single bonds or divalent groups. Specific examples of divalent groups include alkylene groups and arylene groups.

[0319] An alkylene group is a divalent group obtained by removing two hydrogen atoms from an alkane. Specific examples of alkylene groups include divalent groups that have a structure obtained by removing one more hydrogen atom from the alkyl group examples mentioned above.

[0320] An arylene group is a divalent group obtained by removing two hydrogen atoms from an aromatic hydrocarbon. A specific example is a divalent group having a structure obtained by removing one more hydrogen atom from the aryl group example mentioned above. Furthermore, arylene groups may have substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0321] Specific examples of organic compounds that can be used as the first organic compound 161_1 are shown in structural formulas (100) to (112). However, the organic compounds that can be used as the first organic compound 161_1 are not limited to these.

[0322]

[0323] Structural formula (100) is Pyrrd-Phen, structural formula (101) is 4,7-bis[4-(1-pyrrolidinyl)phenyl]-1,10-phenanthroline (abbreviation: PrdP2Phen), structural formula (104) is 4,7-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine-1-yl)-1,10-phenanthroline (abbreviation: 4,7hpp2Phen), structural formula (105) is 4,7-di(2,3,3a,4,5,6,7,7a-octahydro-1H-isoindole-2-yl)-1,10-phenanthroline (abbreviation: Hid2Phen), and structural formula (107) is 2,2' The structural formula (108) is 2-(1,3-phenylene)bis[9-(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine-1-yl)-1,10-phenanthroline] (abbreviation: mhppPhen2P), the structural formula (109) is 2,9-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine-1-yl)-1,10-phenanthroline (abbreviation: 9Ph-2hppPhen), and the structural formula (109) is 2,9-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine-1-yl)-1,10-phenanthroline (abbreviation: 2,9hpp2Phen).

[0324] Furthermore, it is preferable that the minimum value of the ESP of the first organic compound 161_1 is small (a negative value with a large absolute value), as this increases the efficiency of interaction with the metal material 161_M. In organic compounds having a phenanthroline ring, the ESP tends to be negative around the nitrogen atom of the phenanthroline ring, but by introducing an electron-donating group to the phenanthroline ring, the ESP around the nitrogen atom of the phenanthroline ring can be further reduced (the absolute value of the negative value increases). Note that ESP is the interaction energy between a positive point charge with a unit electric charge and the electron distribution of a molecule. The value of ESP also changes depending on the threshold of electron density. To increase the efficiency of interaction with the metal material 161_M, it is preferable that the minimum value of the ESP of the first organic compound 161_1 is smaller (larger in the negative direction) than the minimum value of the ESP of a phenanthroline ring without substituents. Specifically, the threshold of the electron density distribution in the atomic unit system is 0.0004 e / a ０ ３ In this case, the minimum value of ESP is -0.085E ｈ (E ｈ Hartree Energy (1E) ｈ (= 27.211 eV) is preferably less than or equal to -0.090 E ｈ The following is even more preferable: The threshold for the electron density distribution is 0.003 e / a ０ ３ In this case, the minimum value of ESP is -0.12E ｈ The following is preferable: -0.13E ｈ The following are even more preferable.

[0325] 《Estimation of Properties by Quantum Chemical Calculations》 The minimum ESP values ​​of the organic compounds represented by structural formulas (100) to (109) were estimated using quantum chemical calculations. For comparison, the minimum ESP values ​​were also estimated similarly for BPhen, mPPhen2P, NBPhen, and Phen. The structural formulas of BPhen, mPPhen2P, NBPhen, and Phen are shown below.

[0326]

[0327] Gaussian09 was used as the quantum chemical calculation program. The calculations were performed using an HPE SGI8600. The most stable ground state structure of the first organic compound 161_1 was calculated using density functional theory (DFT). The basis set used was 6-311G(d,p), and the functional was B3LYP.

[0328] Table 6 shows the estimated minimum ESP value for the ground state of the first organic compound 161_1. ESP is the interaction energy between a positive point charge with unit electric charge and the electron distribution of a molecule. The ESP value also changes depending on the electron density threshold. In Table 6, the density value in atomic units is 0.0004 e / a. ０ ３ or 0.003e / a ０ ３ The ESP in the electron density distribution under these conditions is shown.

[0329]

[0330] From Table 6, the organic compounds represented by structural formulas (100) to (105) have an electron density distribution threshold of 0.0004 e / a ０ ３ In this case, the minimum value of ESP is -0.085E ｈ The following was found, and it was determined that it is most preferable to use it for the first organic compound 161_1. On the other hand, the minimum value of the ESP of the organic compound represented by structural formulas (106) to (109) is -0.085E ｈ It turned out to be larger.

[0331] The organic compounds represented by structural formulas (100) to (105) are organic compounds having electron-donating groups at positions 4 and 7 of the 1,10-phenanthroline ring, which explains why they yielded the most favorable values.

[0332] The organic compound represented by structural formula (106) is an organic compound having electron-donating groups at positions 4 and 7 of the 1,10-phenanthroline ring, but it uses an N-carbazolyl group as the electron-donating group. In the case of the N-carbazolyl group, the lone pair of electrons on the nitrogen atom contributes to the aromaticity, so compared to groups in which the lone pair of electrons on the nitrogen atom does not contribute to the aromaticity, the electron-donating ability to the phenanthroline ring is reduced, making it difficult to lower the minimum value of ESP, resulting in this outcome.

[0333] The organic compounds represented by structural formulas (107) to (109) are organic compounds having electron-donating groups at positions 2 and 9 of the 1,10-phenanthroline ring. When electron-donating groups are introduced at positions 2 and 9 of the 1,10-phenanthroline ring, the electron-donating effect to nitrogen at positions 1 and 10 of the 1,10-phenanthroline ring is lower compared to when they are introduced at positions 4 and 7. Therefore, it is more preferable that the substitution positions of the electron-donating groups on the 1,10-phenanthroline ring are at positions 4 and 7.

[0334] Furthermore, if the first organic compound 161_1 has high basicity, it becomes easier for the first organic compound 161_1 to interact with holes. Therefore, the hole transport performance in the first layer 161a using the first organic compound 161_1 can be significantly reduced. Consequently, it is possible to prevent holes from being transported from the first layer 161a to the second layer 162a, which is preferable because it allows for the creation of an efficient light-emitting device. Specifically, it is preferable that the acid dissociation constant pKa of the first organic compound 161_1 is 8 or higher, more preferably 10 or higher, and even more preferably 12 or higher.

[0335] If the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa can be determined for each structural component of the organic compound, and the largest pKa selected from among them can be considered as the acid dissociation constant pKa of that organic compound.

[0336] Alternatively, the acid dissociation constant can be determined by calculation. For example, the acid dissociation constant pKa can be determined using the following calculation method.

[0337] The initial molecular structure of each molecule used in the computational model is the most stable structure (singlet ground state) obtained from first-principles calculations.

[0338] For the first-principles calculations described above, the Jaguar quantum chemistry calculation software from Schrödinger AG will be used to calculate the most stable structure in the singlet ground state using density functional theory (DFT). The basis set used will be 6-31G**, and the functional will be B3LYP-D3. The structure to be used for quantum chemistry calculations will be sampled by performing conformational analysis using Mixed torsional / Low-mode sampling with the Maestro GUI from Schrödinger AG.

[0339] In the pKa calculation, one or more atoms in each molecule are designated as basic sites. A MacroModel is used to search for the stable structure of the protonated molecule in water, and conformational searches are performed using the OPLS2005 force field. The lowest energy conformational isomer is then used. The Jaguar pKa calculation module is used; after structural optimization with B3LYP / 6-31G*, a single-point calculation is performed with cc-pVTZ(+), and the pKa value is calculated using empirical corrections for functional groups. For molecules where one or more atoms are designated as basic sites, the largest value among the obtained results is adopted as the pKa value. The obtained pKa values ​​are shown.

[0340] The acid dissociation constant pKa of 2,9hpp2Phen is 13.35, the acid dissociation constant pKa of 4,7hpp2Phen is 13.42, the acid dissociation constant pKa of Pyrrd-Phen is 11.23, the acid dissociation constant pKa of mPPhen2P is 5.16, the acid dissociation constant pKa of NBPhen is 5.59, and the acid dissociation constant pKa of BPhen is 5.62.

[0341] <Second Organic Compound 161_2> As the second organic compound 161_2, it is preferable to use an organic compound having electron-transporting properties. As an organic compound having electron-transporting properties, the electron mobility at which the square root of the electric field strength [V / cm] is 600 is 1 × 10⁻⁶. −７ cm ２ / Vs or more, preferably 1 x 10 −６ cm ２A material having an electron mobility of / Vs or higher is preferred. However, any material with higher electron transport capabilities than holes can be used.

[0342] Furthermore, organic compounds having a π-electron-deficient heteroaromatic ring are preferred as electron-transporting organic compounds. Preferred π-electron-deficient heteroaromatic rings include heteroaromatic rings having an azole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), heteroaromatic rings having a pyridine skeleton, heteroaromatic rings having a diazine skeleton, and heteroaromatic rings having a triazine skeleton. Diazine rings (pyrazine ring, pyrimidine ring, pyridazine ring) or triazine rings are particularly preferred because they are electrochemically stable and have high electron-transporting properties.

[0343] An example of an organic compound that can be used in the second organic compound 161_2 is the organic compound represented by the following general formula (G1-1).

[0344]

[0345] In the above general formula (G1-1), A １ A ２ and A ３ Each of these independently represents a substituted or unsubstituted heteroaromatic ring with 1 to 30 carbon atoms, A １ A ２ and A ３ They may form fused rings with each other.

[0346] The organic compound represented by general formula (G1-1) has a conjugated double bond in which the nitrogen atoms on each heteroaromatic ring are arranged in the order N-C-C-N, and has the function of interacting with metals at three or more dentations. Because organic compounds having such a structure readily interact with metals, they can be suitably used as the second organic compound 161_2.

[0347] In the above general formula (G1-1), A １ A ２ and A ３Examples of substituted or unsubstituted heteroaromatic rings having 1 to 30 carbon atoms, represented by A, include heteroaromatic rings having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthiliidine ring, azafluorantene ring), heteroaromatic rings having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, sinnoline ring, pteridine ring, phenazine ring), heteroaromatic rings having a triazine skeleton, and heteroaromatic rings having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. １ A ２ and A ３ The substituted or unsubstituted heteroaromatic rings with 1 to 30 carbon atoms represented by these are not limited to these. １ A ２ and A ３ They may form fused rings with each other. For example, A １ and A ２ These molecules may bond to each other to form a phenanthroline ring.

[0348] Furthermore, an example of an organic compound that can be used in the second organic compound 161_2 is the organic compound represented by the following general formula (G2-1).

[0349]

[0350] In the general formula (G2-1), X １ From X ６ Each of these independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, R １ From R ４Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. Alternatively, in general formula (G2-1), X １ From X ６ These may be bonded to each other directly or via divalent groups to form a fused ring. Specific examples of divalent groups include alkylene groups and arylene groups.

[0351] It is more preferable that the organic compound having the function of interacting with the metal at three or more dentations, such as the organic compound represented by general formula (G2-1), has at least one of the following: a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, or a heteroaromatic ring having a triazine skeleton. Since these rings have excellent electrochemical stability, a reliable light-emitting device can be provided. Furthermore, since they have excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0352] Furthermore, an example of an organic compound that can be used in the second organic compound 161_2 is the organic compound represented by the following general formula (G3-1).

[0353]

[0354] In the general formula (G3-1), X １ From X ４ Each of these independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, R １ From R ６ Each of these independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0355] Furthermore, an example of an organic compound that can be used in the second organic compound 161_2 is the organic compound represented by the following general formula (G4-1).

[0356]

[0357] In the general formula (G4-1), X １ From X ５ Each of these independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, R １ From R ６ Each of these independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0358] Organic compounds having a pyridine skeleton are preferred because they have a high LUMO level. For example, X in general formulas (G2-1), (G3-1), and (G4-1) １ and X ２ When carbon is represented, the organic compound has a pyridine skeleton and therefore has a high LUMO level, and when it interacts with a metal, it can form a composite material with a high SOMO level. In other words, an organic compound having a pyridine ring and a function of interacting at three or more dentations can form an intermediate layer with high electron injection properties by interacting with a metal.

[0359] Furthermore, organic compounds having a diazine skeleton or triazine skeleton are preferred because they are electrochemically stable and have high electron transport properties. For example, X in general formulas (G2-1), (G3-1), and (G4-1) １ and X ２When at least one of the elements represents nitrogen, the organic compound has a diazine or triazine skeleton, making it electrochemically stable and highly electron-transporting. When it interacts with a metal, it can form a stable and highly electron-transporting composite material. In other words, an organic compound having a diazine ring or triazine ring and a function that interacts at three or more dentations can form a reliable intermediate layer by interacting with a metal.

[0360] Furthermore, an example of an organic compound that can be used in the second organic compound 161_2 is the organic compound represented by the following general formula (G1-2).

[0361]

[0362] In the above general formula (G1-2), A １ and A ２ Each of these independently represents a substituted or unsubstituted heteroaromatic ring with 1 to 30 carbon atoms, A １ and A ２ They may form fused rings with each other, A １ It has two or more nitrogen atoms.

[0363] Organic compounds represented by the general formula (G1-2) have conjugated double bonds in which the nitrogen atoms on the heteroaromatic ring are arranged in the order N-C-C-N, and have the function of interacting with metals at two or more dentations. Because organic compounds having such a structure readily interact with metals, they can be suitably used as intermediate layers.

[0364] In the above general formula (G1-2), A １ Examples of substituted or unsubstituted heteroaromatic rings having 1 to 30 carbon atoms represented by A include heteroaromatic rings having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, sinnoline ring, pteridine ring, phenazine ring), heteroaromatic rings having a triazine skeleton, and heteroaromatic rings having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring). ２Examples of substituted or unsubstituted heteroaromatic rings having 1 to 30 carbon atoms, represented by A, include heteroaromatic rings having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthiliidine ring, azafluorantene ring), heteroaromatic rings having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, sinnoline ring, pteridine ring, phenazine ring), heteroaromatic rings having a triazine skeleton, and heteroaromatic rings having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. １ and A ２ The substituted or unsubstituted heteroaromatic rings with 1 to 30 carbon atoms represented by these are not limited to these. １ , and A ２ They may form fused rings with each other. For example, A １ and A ２ These molecules may bond to each other to form a pyrazinoquinoxaline ring.

[0365] Furthermore, an example of an organic compound that can be used in the second organic compound 161_2 is the organic compound represented by the following general formula (G2-2).

[0366]

[0367] In the general formula (G2-2), X １ From X ４ At least one of them represents nitrogen (N), and the others each independently represent carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, R １ From R ４each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. Alternatively, in General Formula (G2-2), X １ to X ４ may be bonded to each other directly or via a divalent group to form a fused ring. Specific examples of the divalent group include, for example, an alkylene group, an arylene group, and the like.

[0368] It is more preferable that the organic compound having a function of interacting with a metal at two or more coordination sites, such as the organic compound represented by General Formula (G2-2), has a heteroaromatic ring having a diazine skeleton or a heteroaromatic ring having a triazine skeleton. Since these rings have excellent electrochemical stability, a light-emitting device with favorable reliability can be provided. In addition, since these rings have excellent electron-transport properties, a light-emitting device with reduced driving voltage can be provided.

[0369] Moreover, as an example of an organic compound that can be used for the second organic compound 161_2, an organic compound represented by the following General Formula (G3-2) can be used.

[0370]

[0371] In General Formula (G3-2), X １ or X ２ one represents nitrogen (N), and the other represents carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R １ to R ６ each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0372] Further, examples of organic compounds that can be used for the second organic compound 161_2 include an organic compound represented by the following general formula (G4-2).

[0373]

[0374] In general formula (G4-2), X １ to X ３ at least one of represents nitrogen (N), the others each independently represent carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, R １ to R ５ each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0375] An organic compound having a pyridine skeleton is preferable because it has a high LUMO level. For example, X in general formulas (G2-2) and (G4-2) １ and X ２ , and X in general formula (G3-2) １ represents carbon, the organic compound has a pyridine skeleton, and thus has a high LUMO level, and can form a composite material having a high SOMO level when interacting with a metal. That is, an organic compound having a pyridine ring and a function of interacting at two or more sites can form an intermediate layer having high electron injection properties by interacting with a metal.

[0376] Further, an organic compound having a diazine skeleton or a triazine skeleton is preferable because it is electrochemically stable and has high electron transport properties. For example, X in general formulas (G2-2) and (G4-2) １ and X ２ at least one of, and X in general formula (G3-2) １When nitrogen is represented, the organic compound has a diazine or triazine skeleton, and is therefore electrochemically stable and has high electron transport properties. When it interacts with a metal, it can form a stable composite material with high electron transport properties. In other words, an organic compound having a diazine ring or triazine ring and having a function of interacting at two or more dentates can form a reliable intermediate layer by interacting with a metal.

[0377] Below, we show more specific examples of organic compounds that can be used in the second organic compound 161_2, and the organic compounds represented by the above-mentioned general formulas (G1-1) to (G4-2), in general formulas (250) to (268).

[0378]

[0379]

[0380] In general formulas (250) to (268), R １１ From R １６２ Each of these independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0381] Furthermore, substituents that can be applied to the above-mentioned general formulas (G1-1) to (G4-2) and general formulas (250) to (268) include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, aryl groups having 6 to 30 carbon atoms, arylene groups having 6 to 30 carbon atoms, and heteroaryl groups having 1 to 30 carbon atoms. Some or all of the hydrogen atoms may be deuterium. Also, the groups that can be applied to the above general formulas are not limited to the following specific examples.

[0382] Specific examples of alkyl groups having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, neohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, and 1-ethylhexyl group.

[0383] Specific examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl group, cyclobutyl group, methylcyclobutyl group, cyclopentyl group, methylcyclopentyl group, isopropylcyclopentyl group, tert-butylcyclopropyl group, cyclohexyl group, methylcyclohexyl group, isopropylcyclohexyl group, tert-butylcyclohexyl group, cycloheptyl group, methylcycloheptyl group, isopropylcycloheptyl group, cyclooctyl group, methylcyclooctyl group, isopropylcyclohexyl group, cyclononyl group, methylcyclononyl group, cyclodecyl group, adamantyl group, and the like.

[0384] Specific examples of aryl groups having 6 to 30 carbon atoms include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, 1-naphthyl group, 2-naphthyl group, fluorenyl group, 9,9-dimethylfluorenyl group, spirobifluorenyl group, phenanthryl group, anthryl group, fluoranthenyl group, etc. When an aryl group having 6 to 30 carbon atoms has substituents, examples of substituents include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, phenyl group, etc.

[0385] Specific examples of arylene groups having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorene-diyl group, acenaphthene-diyl group, anthracene-diyl group, phenanthrene-diyl group, terphenyl-diyl group, triphenylene-diyl group, phenanthrene-diyl group, tetracene-yl group, benzanthracene-diyl group, pyrene-diyl group, and spirobi[9H-fluorene]-diyl group. When an arylene group having 6 to 30 carbon atoms has substituents, examples of substituents include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, and phenyl groups.

[0386] A heteroaryl group having 1 to 30 carbon atoms is a monovalent group obtained by removing one hydrogen atom from one of the carbon atoms forming the ring of a monocyclic or polycyclic heterocyclic aromatic compound having 1 to 30 carbon atoms. Specific examples of heteroaryl groups having 1 to 30 carbon atoms include 1,3,5-triazine-2-yl group, 1,2,4-triazine-3-yl group, pyrimidine-4-yl group, pyrazine-2-yl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, carbazolyl group, dibenzofuranyl group, dibenzothiophenyl group, benzonaphthofuranyl group, benzonaphthothiophenyl group, indolocarbazolyl group, benzoflocarbazolyl group, benzothienocarbazolyl group, indenocarbazolyl group, and dibenzocarbazolyl group. If the heteroaryl group has substituents, examples of substituents include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, and phenyl groups.

[0387] The following are examples of organic compounds that can be used in the second organic compound 161_2, and specific examples of organic compounds represented by the general formulas (G1-1) to (G4-2) described above.

[0388]

[0389]

[0390]

[0391] The organic compounds that can be used as the second organic compound 161_2 are not limited to those described above. Any organic compound having electron-transporting properties that forms an excited complex with the first organic compound 161_1 can be used as the second organic compound 161_2.

[0392] Examples of organic compounds with electron-transporting properties include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), and 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole Organic compounds having an azole skeleton such as (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[ Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), vasophenanthroline (abbreviation: BPhen), vasocuproin (abbreviation: BCP), NBPhen, mPPhen2P, 4,7-diphenyl-2,9-bis(4-(1-phenyl-1H-benzo[d]imidazole-2-yl)phenyl)-1,10-phenanthroline (abbreviation: DBimiBphen), and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq- II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3' -(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofloflo[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 8-(p-terphenyl-3-yl)-4-[ 3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 8-([1,1':4',1''-terphenyl-2,4,5,6,2',3',5',6',2'',3'',4'',5'',6''-d13]-3-yl)-4-{3-[(dibenzothiophen-1,2,3,6,7,8,9-d7)-4-yl]phenyl-2,4,6-d3}-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm-d, ２３), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzoflo[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-([2,2'-binaphthalene]-6-yl)-4-[3-(dibenzo Thiofen-4-yl)phenyl]-[1]benzoflou[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalene-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4 Organic compounds having a diazine skeleton, such as -yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTZn), and 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl 1,3,5-triazine (abbreviation: mBnfBPTZn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTZn-02), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTZn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,35-triazine (abbreviation: mFBPTZn), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTZn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mD BtBPTZn), 2,4,6-Tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTZn), 11-[4-(biphenyl-4-yl) -6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindoro[2,3-a]carbazole (abbreviation: BP-Icz(II)TZn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTZn), 3-[9-(4,6-diphenyl-1,3,5-triazine] Examples of organic compounds having a triazine skeleton include di(2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTZn) and 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (abbreviated as mBP-TPDBfTZn).

[0393] Among those mentioned above, organic compounds having a phenanthroline ring, such as BPhen, BCP, NBPhen, and mPPhen2P, particularly a 1,10-phenanthroline ring, are more preferable because the two nitrogen atoms they contain can coordinate to metals, thus facilitating interactions with metals. Furthermore, organic compounds having a phenanthroline ring dimer structure, such as mPPhen2P, are more preferable due to their excellent stability.

[0394] Furthermore, it is preferable that the number of carbon atoms in the organic compound used in the second organic compound 161_2 is between 25 and 100. By having such a number of carbon atoms, it is possible to obtain an organic compound with excellent sublimation properties, which suppresses the thermal decomposition of the organic compound during vacuum deposition and allows for good material utilization efficiency. Also, the glass transition temperature (T ｇ ) Organic compounds with a temperature of 100°C or higher can be used. This makes it possible to create an intermediate layer that is less prone to crystallization. Therefore, when processing a part of the organic compound layer by lithography, even if it is affected by oxygen or water in the atmosphere or chemicals or water during the process, it is possible to create a layer that is less prone to crystallization. Therefore, it is possible to prevent an increase in the driving voltage or a decrease in the current efficiency of the light-emitting device due to the crystallization of the intermediate layer. Therefore, T ｇ By using an organic compound with a temperature of 100°C or higher as the second organic compound 161_2, a portion of the organic compound layer can be suitably used as an intermediate layer in a light-emitting device processed by lithography.

[0395] An organic compound having a phenanthroline ring, and T ｇ As an organic compound with a temperature of 100°C or higher, NBPhen (T ｇ : 165℃), mPPhen2P(T ｇ : 135℃), 2,2'-(biphenyl-4,4'-diyl)bis(9-phenyl-1,10-phenanthroline) (abbreviation: PPhen2BP) (T ｇ : 166℃), 2,2'-biphenyl-3,3'-diirbis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2BP) (T ｇ : 144℃), 2,8-bis(phenanthroline-5-yl)dibenzofuran (abbreviation: 2,8Phen2DBf) (T ｇ : 210℃), 5,5',5''-(benzene-1,3,5-triyl)tri-1,10-phenanthroline (abbreviation: Phen3P) (T ｇ Examples include: 257°C, etc. ｇFor example, this can be done using a differential scanning calorimetry system (DSC8500, manufactured by PerkinElmer Japan Co., Ltd.), by placing the powder on an aluminum cell, heating it at a rate of 40°C / min, and then taking the measurement.

[0396] Furthermore, as the second organic compound 161_2, an organic compound with an acid dissociation constant pKa of 4 or more and less than 8 can be used. This is preferable because it reduces the hole transportability of the second organic compound 161_2, thereby reducing the hole transportability in the first layer 161a of the intermediate layer 160a, and preventing holes from being transported from the first layer 161a to the second layer 162a, thus enabling the creation of an efficient light-emitting device. Also, if the acid dissociation constant pKa becomes too high, the solubility in water increases, which may result in poor resistance to water and chemicals used in the lithography process. For this reason, it is preferable that the acid dissociation constant pKa of the second organic compound 161_2 is 4 or more and less than 8.

[0397] In a layer containing a combination of metallic material 161_M, a first organic compound 161_1, and a second organic compound 161_2, the interaction between the materials occurs more efficiently compared to a layer containing only two of these materials (for example, a layer containing metallic material 161_M and the first organic compound 161_1, or a layer containing metallic material 161_M and the second organic compound 161_2). This can be confirmed by using an odd-numbered metal for metallic material 161_M and measuring the spin density of the film containing each material using electron spin resonance (ESR).

[0398] For example, it is preferable that the spin density measured by ESR of a film containing a metal, the first organic compound 161_1, and the second organic compound 161_2 is higher than the spin density measured by ESR of a film containing a metal and the first organic compound 161_1, or the spin density measured by ESR of a film containing a metal and the second organic compound 161_2. In such cases, it can be confirmed that the interaction between the materials occurs more efficiently in a layer having a combination of the metal, the first organic compound 161_1, and the second organic compound 161_2 compared to a layer having only two of these materials. It is preferable to measure the spin density using electron spin resonance at room temperature.

[0399] More specifically, for a mixed film containing a metal and a first organic compound 161_1, the spin density resulting from a signal observed around a g value of 2.00 by electron spin resonance is 2 × 10⁻¹⁰ １６ spins / cm ３ The following applies to the mixed film containing the metal and the second organic compound 161_2: For example, the spin density resulting from the signal observed around a g value of 2.00 by electron spin resonance is 2 × 10⁻¹⁰. １６ spins / cm ３ The following applies to a mixed film containing the first organic compound 161_1 and the second organic compound 161_2: For example, the spin density resulting from the signal observed around a g value of 2.00 by electron spin resonance is 2 × 10⁻¹⁰. １６ spins / cm ３ When the following conditions are met, a mixed film having a metal, a first organic compound 161_1, and a second organic compound 161_2 has a spin density due to a signal observed, for example, around a g value of 2.00 by electron spin resonance spectroscopy, which is 5 × 10⁻¹⁰. １６ spins / cm ３ More specifically, 1 x 10 １７ spins / cm ３ In the above case, it can be confirmed that in a layer having a combination of metal, a first organic compound 161_1, and a second organic compound 161_2, the interaction between the materials occurs more efficiently compared to a layer having only two of these materials.

[0400] Furthermore, the ratio of the metal is preferably 0.1 to 10 in molar ratio, more preferably 0.2 to 5, and even more preferably 0.5 to 2, relative to the total of the first organic compound 161_1 and the second organic compound 161_2. Alternatively, it is preferably 0.005 to 0.3 in volume ratio, more preferably 0.01 to 0.1, and even more preferably 0.01 to 0.05. By mixing the metal with the first organic compound 161_1 and the second organic compound 161_2 in such ratios, an intermediate layer with good electron injection properties can be provided. Furthermore, the ratio of the first organic compound 161_1 is preferably 0.1 to 10 in volume ratio, more preferably 0.2 to 5, and even more preferably 0.5 to 2, relative to the second organic compound 161_2. By mixing the first organic compound 161_1 and the second organic compound 161_2 in this ratio, an intermediate layer with good electron transport properties can be provided.

[0401] Furthermore, the film thickness of the first layer 161a located on the anode side of the intermediate layer 160a is preferably 3 nm to 20 nm, and more preferably 5 nm to 10 nm. By doing so, the composite material in which the metal, the first organic compound 161_1, and the second organic compound 161_2 are mixed can function well, and a light-emitting device exhibiting high luminescence efficiency can be provided.

[0402] Next, we will describe the preferred configurations of the second and third layers when layer 200 is applied to the first layer among the intermediate layers.

[0403] [Second Layer] It is preferable to apply a layer containing a third organic compound and a fourth organic compound to the second intermediate layer. This is preferable because it allows for good injection of holes into the upper light-emitting layer.

[0404] <Third Organic Compound> It is preferable to use an organic compound that has hole-transporting properties as the third organic compound. Various organic compounds can be used as hole-transporting organic compounds, such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.). −６ cm ２ It is preferable that the organic compound has a hole mobility of 1 / Vs or higher. The hole-transporting organic compound is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, anthracene rings, naphthalene rings, etc. are preferred. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, or a thiophene skeleton is preferred, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or heteroaromatic ring is further condensed thereon is preferred.

[0405] Organic compounds having such hole-transporting properties more preferably have at least one of the following skeletons: a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, they may be aromatic amines having substituents including a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Furthermore, it is preferable that these hole-transporting organic compounds are substances having an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime.

[0406] Specifically, organic compounds having hole transport properties as described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviated as BnfBB1BP), and N,N-bis(4-biphenyl)benzo[b]naph To[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-bife Nylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl -4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-([2,2'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-([2,2'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([1,2'-binaphthyl]-4-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-([1,2'-binaphthyl]-5-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyl Triphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris (Biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis( Biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl) 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole 9,9-9-9H-fluoren-2-amine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluoren]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio[9H-fluoren-4- Examples include amines, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9''-telcarbazole (abbreviation: PSiCzGI), etc.

[0407] Furthermore, as materials possessing hole transport properties, aromatic amine compounds such as N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B) can also be used.

[0408] <Fourth Organic Compound> It is preferable to use a material that is an acceptor of the third organic compound for the fourth organic compound. As the acceptor, it is preferable to use an organic compound having an electron-withdrawing group (halogen group, cyano group, etc.), and it is more preferable to use an organic compound having four or more of at least one of the halogen group and cyano group. A specific example is 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ４ -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F ６Examples include -TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and therefore preferred. Furthermore, [3]radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups, cyano groups, etc.) are preferred because they have very high electron-accepting properties. Specifically, examples include α,α',α''-1,2,3-cyclopropanetriylidenates [4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates [2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates [2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds described above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used as acceptor substances.

[0409] In the second layer, it is preferable that a signal observed by electron spin resonance is observed. For example, the spin density due to the signal observed around a g value of 2.00 is 1 × 10⁻⁶. １７ spins / cm ３ The above is more preferable, 1 × 10 １８ spins / cm ３ The above is more preferable, 1 × 10 １９ spins / cm ３ The above is even more preferable. By doing so, the second layer can function as a charge generation layer. Furthermore, it is possible to fabricate a light-emitting device with a low driving voltage and high efficiency.

[0410] [Third layer] A third layer may be provided between the first and second layers of the intermediate layer to facilitate the exchange of electrons between these two layers.

[0411] The third layer contains an electron-transporting material and has the function of preventing interaction between the first and second layers and smoothly transferring electrons. Preferably, the LUMO level of the electron-transporting material contained in the third layer 163 is between the LUMO level of the acceptor material in the second layer 162 and the LUMO level of the organic compound contained in the layer in contact with the intermediate layer 160 in the light-emitting unit on the first electrode 101 side. The specific energy level of the LUMO level of the electron-transporting material used in the third layer 163 is preferably -5.0 eV or higher, preferably -5.0 eV or higher and -3.0 eV or lower, more preferably -4.30 eV or higher and -3.00 eV or lower, and more preferably -4.30 eV or higher and -3.30 eV or lower. This is preferable because it makes it easier to inject electrons generated in the second layer into the first layer, thereby suppressing an increase in the driving voltage of the light-emitting device. Furthermore, it is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand as the electron-transporting material used in the third layer 163.

[0412] Specifically, these include perylenetetracarboxylic acid derivatives such as diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviated as HATNA-F6), 3,4,9,10-perylenetetracarboxylic acid diimide (abbreviated as PTCDI), 3,4,9,10-perylenetetracarboxyl-bis-benzimidazole (abbreviated as PTCBI), (C60-Ih)[5,6]fullerene (abbreviated as C60), (C70-D5h)[5,6]fullerene (abbreviated as C70), and phthalocyanine (abbreviated as H ２Pc) can be used. In addition, metal phthalocyanines having copper, zinc, cobalt, iron, chromium, nickel, etc., and their derivatives can be used, such as copper phthalocyanine (abbreviated as CuPc), zinc phthalocyanine (abbreviated as ZnPc), cobalt phthalocyanine (abbreviated as CoPc), iron phthalocyanine (abbreviated as FePc), tin phthalocyanine (abbreviated as SnPc), tin oxide phthalocyanine (abbreviated as SnOPc), titanium oxide phthalocyanine (abbreviated as TiOPc), and vanadium oxide phthalocyanine (abbreviated as VOPc). Phthalocyanine-based metal complexes such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine are particularly preferred.

[0413] Furthermore, the thickness of the third layer 163 is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less.

[0414] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, the configuration examples can be appropriately combined.

[0415] (Embodiment 3) This embodiment describes other configurations of a light-emitting device that can be used in a display device according to one aspect of the present invention.

[0416] Figure 12A shows a light-emitting device 130, which is an example of a light-emitting device that can be used in a display device according to one embodiment of the present invention. The light-emitting device 130 is a light-emitting device having an organic compound layer 103 including a light-emitting layer 113 between a first electrode 101 including an anode and a second electrode 102 including a cathode.

[0417] Figure 12B shows a light-emitting device 130, which is another example of a light-emitting device that can be used in a display device according to one embodiment of the present invention. The light-emitting device 130 is a tandem type light-emitting device. The light-emitting device 130 has an organic compound layer 103, a first light-emitting unit 501 including a first light-emitting layer 113_1, a second light-emitting unit 502 including a second light-emitting layer 113_2, and an intermediate layer 160. The intermediate layer 160 has a first layer 161, a second layer 162, and a third layer 163 between the first layer 161 and the second layer 162.

[0418] In this embodiment, a light-emitting device having one intermediate layer 160 and two light-emitting units is described as an example, but a light-emitting device having n (where n is an integer of 1 or more) intermediate layers and n+1 light-emitting units may also be used.

[0419] For example, the light-emitting device 130 shown in Figure 12C is an example of a tandem-type light-emitting device in which n is 2 and the organic compound layer 103 includes a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, and a third light-emitting unit 503 including a third light-emitting layer 113_3. The color gamut of the light emitted by the light-emitting layer in each light-emitting unit may be the same or different. Furthermore, the light-emitting layer may be a single layer or a laminated structure. For example, white light emission can be obtained by configuring the first and third light-emitting units to emit light in the blue region, and the second light-emitting unit to emit light in the red and green regions from the laminated light-emitting layer.

[0420] Furthermore, the light-emitting device 130 shown in Figure 12D is an example of a tandem-type light-emitting device in which n is 3 and the organic compound layer 103 includes a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, a third light-emitting unit 503, a third intermediate layer 160_3, and a fourth light-emitting unit 504 including a fourth light-emitting layer 113_4. The color gamut of the light emitted by the light-emitting layer in each light-emitting unit may be the same or different. Also, the light-emitting layer may be a single layer or a laminated structure. For example, among the four light-emitting units, any three may be blue (B) and the remaining one may be green (G), any two may be blue (B) and the remaining two may be yellow (Y), or any one may be red (R), another one may be green (G), and the remaining two may be blue (B).

[0421] The light-emitting device 130 may be a light-emitting device fabricated using, for example, a lithography method. In the case of a light-emitting device fabricated using a lithography method, at least the light-emitting layer 113 or the second light-emitting layer 113_2 and the organic compound layer on the first electrode 101 side are processed simultaneously, so their edges are generally aligned vertically.

[0422] Furthermore, the organic compound layer 103 may include other functional layers in addition to the light-emitting layer. Figure 12A illustrates a configuration in which the organic compound layer 103 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115 in addition to the light-emitting layer 113. Furthermore, the first light-emitting unit 501 and the second light-emitting unit 502 may include other functional layers in addition to the light-emitting layer. Figure 12B illustrates a configuration in which the first light-emitting unit 501 includes a hole injection layer 111, a first hole transport layer 112, and a first electron transport layer 114, in addition to the first light-emitting layer 113, and the second light-emitting unit 502 includes a second light-emitting layer 113, a second hole transport layer 112, a second electron transport layer 114, and an electron injection layer 115. However, the configuration of the organic compound layer 103 in the present invention is not limited to this, and it is possible to omit any of the layers or to provide other layers. Typical examples of other layers include carrier blocking layers (hole blocking layers, electron blocking layers) and exciton blocking layers.

[0423] Next, we will describe the configuration of the light-emitting device 130 other than the intermediate layer 160.

[0424] 《Configuration of the First Electrode》 The first electrode 101 is an electrode including an anode. The first electrode 101 may have a layered structure, in which case the layer in contact with the organic compound layer 103 functions as the anode. The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a large work function (specifically 4.0 eV or more). Specifically, examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium oxide (IWZO) containing tungsten oxide and zinc oxide. These conductive metal oxide films are usually formed by sputtering, but they may also be fabricated using methods such as the sol-gel method. An example of a fabrication method is to form indium zinc oxide by sputtering using a target to which 1 to 20 wt% zinc oxide is added to indium oxide. Furthermore, indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials that can be used for the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride). Alternatively, graphene can also be used as a material for the anode. By using the second layer 162 in the intermediate layer 160 as a layer in contact with the anode (typically a hole injection layer), the electrode material can be selected regardless of the work function.

[0425] 《Configuration of the Hole Injection Layer》 The hole injection layer 111 is provided in contact with the anode and has the function of facilitating the injection of holes into the organic compound layer 103 (first light-emitting unit 501). The hole injection layer 111 is H ２It can be formed from phthalocyanine compounds such as Pc and CuPc, aromatic amine compounds such as DPAB and DNTPD, or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviated as PEDOT / PSS).

[0426] Furthermore, the hole injection layer 111 may be formed from a material having electron acceptor properties. The materials listed above as acceptor materials used in the second layer 162 of the intermediate layer 160 can be used in the same manner.

[0427] Furthermore, the hole injection layer 111 may be formed using the hole transport material used in the second layer 162 of the intermediate layer 160.

[0428] Furthermore, in the hole injection layer 111, it is even more preferable that the hole-transporting organic compound used in the composite material has a relatively low HOMO level of -5.7 eV or more and -5.4 eV or less. Having a relatively low HOMO level in the hole-transporting organic compound used in the composite material facilitates the injection of holes into the hole transport layer and makes it easier to obtain a light-emitting device with a good lifetime. In addition, having a relatively low HOMO level in the hole-transporting organic compound used in the composite material moderately suppresses hole induction, resulting in a light-emitting device with an even better lifetime.

[0429] By forming the hole injection layer 111, the hole injection performance is improved, and a light-emitting device with a low driving voltage can be obtained.

[0430] Furthermore, among substances with acceptor properties, organic compounds with acceptor properties are easy to use because they are readily deposited and easy to form films.

[0431] Furthermore, since the second layer 162 in the intermediate layer 160 functions as a hole injection layer, the second light-emitting unit 502 does not have a hole injection layer, but a hole injection layer may be provided in the second light-emitting unit 502.

[0432] 《Composition of Hole Transport Layers》 The hole transport layers (first hole transport layer 112_1, second hole transport layer 112_2) are formed by including an organic compound having hole transport properties. The organic compound having hole transport properties is 1 × 10 −６ cm ２ It is preferable that the hole mobility is greater than or equal to / Vs.

[0433] Examples of organic compounds having hole transport properties include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), BPAFLP, mBPAFLP, PCBA1BP, PCBBi1BP, PCBANB, PCBNBB, and 9,9-dimethyl-N-phenyl Compounds having an aromatic amine skeleton such as −N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), PCBASF, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H -Carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-( 2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H -Bicarbazole, 9-phenyl-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylene-2- Compounds having a carbazole skeleton such as yl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz), compounds having a thiophene skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4,4',4''-(benzene-1,3,Examples of compounds having a furan skeleton include 5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. The substances listed as materials having hole transportability used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer. Furthermore, the use of organic compounds having an amine skeleton and a fluorene skeleton is even more preferable. Organic compounds having an amine skeleton and a fluorene skeleton are preferred because they have good reliability and high hole transportability, thus reducing the power consumption of the light-emitting device.

[0434] 《Configuration of the light-emitting layer》 The light-emitting layer (light-emitting layer 113, first light-emitting layer 113_1, second light-emitting layer 113_2) preferably contains a light-emitting substance and a host material. The light-emitting layer may also contain other materials. Furthermore, it may be a laminate of two layers with different compositions.

[0435] The luminescent material may be a fluorescent material, a phosphorescent material, a material that exhibits thermally activated delayed fluorescence (TADF), or any other luminescent material.

[0436] Examples of materials that can be used as fluorescent materials in the light-emitting layer include the following. Other fluorescent materials can also be used.

[0437] 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAPP2BPy), 5,6-bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl] )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), 9,10-bis(2-biphenyl)-2-(N,N',N'-triphenyl-1,4-phenylenediamine-N-yl)anthracene (abbreviation: 2DPABPhA) 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyra N-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-diamine (abbreviation) Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naph Examples include to[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPPrn-03, are preferred because they exhibit high hole-trapping properties and excellent luminescence efficiency or reliability.

[0438] Also, 5,9-diphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazavolin (abbreviated as DABNA-1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazavolin-3-amine (abbreviated as DABNA-2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-di Phenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazabolin-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazabolin-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)- 5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazabolin (abbreviation: Me-tBu4DABNA), N7,N7,N13,N13,5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazabolino[2,3,4-kl][1,4]benzazabolino[4',3',2':4,5][1,4]benzazabolino[3, Condensed heteroaromatic compounds containing nitrogen and boron, such as 2-b]phenazavolin-7,13-diamine (abbreviated as ν-DABNA) and 2-(4-tert-butylphenyl)benz[5,6]indro[3,2,1-jk]benzo[b]carbazole (abbreviated as tBuPBibc), particularly compounds having a diaza-boranaphtho-anthracene skeleton, can be suitably used because they produce blue emission with a narrow emission spectrum and good color purity.

[0439] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indoro[3,2,1-de]indoro[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazavolin (abbreviation: BBCz-G), 9,11-bis[ Compounds having an indole skeleton, such as 3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indro[3,2,1-de]indro[3',2',1':8,1][1,4]benzazavolino[2,3,4-kl]phenazavolin (abbreviation: BBCz-Y), can be suitably used.

[0440] When using phosphorescent materials as the light-emitting material in the light-emitting layer, possible materials include, for example, the following:

[0441] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazole-3-yl-κN2]phenyl-κC}Iridium(III) (Abbreviation: [Ir(mpptz-dmp) ３ ]), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato) iridium (III) (abbreviation: [Ir(Mptz) ３ ]), Tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) ３ ]) an organometallic iridium complex having a 4H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ３ ]), Tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) Iridium(III) (abbreviation: [Ir(Prptz1-Me) ３]) an organometallic iridium complex having a 1H-triazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim) ３ ]), Tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridine]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ３ ]), organometallic iridium complexes having an imidazole skeleton such as tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazole-2-yl-κN3}-4-cyanophenyl-κC) iridium(III) (abbreviation: CNImIr), tris[(6-tert-butyl-3-phenyl-2H-imidazol[4,5-b]pyrazine-1-yl-κC2)phenyl-κC] iridium(III) (abbreviation: [Ir(cb) ３ Organometallic complexes having a benzimidazolidene skeleton such as ]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C ２’ Iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C ２’ Iridium (III) picolinate (abbreviation: [Ir(CF) ３ ppy) ２ (pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C ２’Examples include organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups, such as iridium(III) acetylacetonate (abbreviated as FIracac), and platinum complexes such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazole-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC1)platinum(II) (abbreviated as PtON-TBBI). These compounds exhibit blue phosphorescence and have emission peaks in the wavelength range from 450 nm to 520 nm. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium can also be used.

[0442] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ３ ]), Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ３ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ２ (acac)), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ２ (acac)), (acetylacetonate)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) ２ (acac)), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmpppm) ２ (acac)), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ２ Organometallic iridium complexes having a pyrimidine skeleton such as (acac) (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me) ２(acac)), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ２ Organometallic iridium complexes having a pyrazine skeleton such as (acac), Tris(2-phenylpyridinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(ppy) ３ ]), bis(2-phenylpyridinate-N,C ２’ Iridium (III) acetylacetonate (abbreviation: [Ir(ppy) ２ (acac)), bis(benzo[h]quinolinate)iridium(III)acetylacetonate (abbreviation: [Ir(bzq) ２ (acac)), Tris(benzo[h]quinolinate) Iridium(III) (abbreviation: [Ir(bzq) ３ ]), Tris(2-phenylquinolinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(pq) ３ ]), bis(2-phenylquinolinato-N,C ２’ Iridium(III) acetylacetonate (abbreviation: [Ir(pq) ２ (acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3) ２ (mbfpypy-d3), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofl[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC}Iridium(III) (abbreviation: Ir(5mtpy-d6) ２ (mbfpypy-iPr-d4)), [2-(methyl-d3)-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) ((abbreviation: Ir(ppy) ２(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mdppy)), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d ３ ) ２ (mdppy-d ３ ) )]), [2-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridinyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy)), Tris{2-[5-(methyl-d3)-4-phenyl-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5m4dppy-d ３ ) ３ In addition to organometallic iridium complexes with a pyridine skeleton such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ３Rare earth metal complexes such as (Phen) (2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridinyl-κN)phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenolate-κO)platinum(II) (abbreviation: Pt(tBudpppymmtBubiz-tBubp) Examples include organometallic platinum complexes such as [2-(4-(3,5-di-tert-butylphenyl)-6-{3-[4-(5'-tert-butyl[1,1':3',1''-terphenyl]-2'-yl)-2-pyridinyl-κN]phenyl-κC2}-2-pyridinyl-κN)phenolato-κO]platinum(II) (abbreviation: Pt(4tButpppypyp-mmtBup)). These compounds mainly exhibit green phosphorescence and have emission peaks in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred due to their outstanding reliability and luminescence efficiency. Compounds in which some of the hydrogen atoms are replaced with deuterium can also be used.

[0443] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) ２ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ２ (dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm) ２ Organometallic iridium complexes having a pyrimidine skeleton such as (dpm)]), (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: [Ir(tppr) ２ (acac)), bis(2,3,5-triphenylpyrazinate)(dipivaloylmethanato) iridium(III) (abbreviation: [Ir(tppr) ２(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ２ Organometallic iridium complexes having a pyrazine skeleton such as (acac), tris(1-phenylisoquinolinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(piq) ３ ]), bis(1-phenylisoquinolinato-N,C ２’ Iridium (III) acetylacetonate (abbreviation: [Ir(piq) ２ (acac)), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl In addition to organometallic iridium complexes with a pyridine skeleton such as [-κC]iridium(III), there are platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), and tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)] ３ (Phen)]), Tris[1-(2-tenoyl)-3,3,3-trifluoroacetonate](monophenanthroline) europium(III) (abbreviation: [Eu(TTA) ３ Examples include rare earth metal complexes such as (Phen)). These are compounds that exhibit red phosphorescence and have emission peaks in the wavelength range of 600 nm to 700 nm. In addition, organometallic iridium complexes having a pyrazine skeleton yield red emission with good chromaticity. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium can also be used.

[0444] In addition to the phosphorescent compounds described above, other known phosphorescent compounds may be selected and used.

[0445] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc. can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can be used. As a metal-containing porphyrin, for example, the protoporphyrin-tin fluoride complex (SnF) shown in the following structural formula is used. ２ (Proto IX)), Mesoporphyrin-Tin Fluoride Complex (SnF ２ (Meso IX), hematoporphyrin-tin fluoride complex (SnF ２ (Hemato IX), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ２ (Copro III-4Me)), Octaethylporphyrin-Tin Fluoride Complex (SnF ２ (OEP)), Ethioporphyrin-Tin Fluoride Complex (SnF ２ (Etio I)), Octaethylporphyrin-Platinum Chloride Complex (PtCl ２ OEP (Open Economic Programme) is another example.

[0446]

[0447] Furthermore, the following structural formulas represent 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazine-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTZn), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenadin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. Among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptability and are reliable. Furthermore, among the skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable, and therefore it is preferable to have at least one of these skeletons.Furthermore, a dibenzofuran skeleton is preferred as the furan skeleton, and a dibenzothiophene skeleton is preferred as the thiophene skeleton. In addition, as the pyrrole skeleton, indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because both the electron-donating and electron-accepting properties of the π-electron-rich heteroaromatic ring are strengthened, and the energy difference between the S1 and T1 levels is reduced, thus efficiently obtaining thermally activated delayed fluorescence. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, etc., can be used as the π-electron-rich skeleton. Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane and volanthrene, aromatic rings having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, heteroaromatic rings, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used. In this way, π-electron-deficient skeletons and π-electron-excess skeletons can be used instead of at least one of π-electron-deficient heteroaromatic rings and π-electron-excess heteroaromatic rings.

[0448]

[0449] Furthermore, a TADF material in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used as the TADF material. Since such a TADF material has a shorter luminescence lifetime (excitation lifetime), it is possible to suppress the decrease in efficiency in the high-brightness region of the light-emitting device. Specifically, materials with the molecular structure shown below are examples.

[0450]

[0451] TADF materials are materials that have a small energy difference between the S1 and T1 levels and possess the ability to convert energy from triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy with only a small amount of thermal energy (reverse intersystem crossing), and singlet excited states can be efficiently generated. Furthermore, triplet excitation energy can be converted into luminescence.

[0452] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances has an extremely small energy difference between the S1 and T1 levels and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0453] Furthermore, as an indicator of the T1 level, the phosphorescence spectrum observed at low temperatures (for example, from 77K to 10K) may be used. For TADF materials, when a tangent is drawn at the short-wavelength tail of the fluorescence spectrum and the energy at the wavelength of the extrapolation is taken as the S1 level, and when a tangent is drawn at the short-wavelength tail of the phosphorescence spectrum and the energy at the wavelength of the extrapolation is taken as the T1 level, it is preferable that the energy difference between the S1 level and the T1 level is 0.3 eV or less, and more preferably 0.2 eV or less.

[0454] Furthermore, when using TADF material as a light-emitting material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0455] Various carrier transport materials can be used as the host material for the light-emitting layer, such as materials with electron transport properties and / or hole transport properties, and the TADF material mentioned above.

[0456] As for materials that possess hole-transporting properties, those previously listed as materials with hole-transporting properties can be used in the same manner.

[0457] As for materials with electron transport properties, those previously listed as materials with electron transport properties can be used in the same way.

[0458] The TADF materials listed above can be used as host materials. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing, and this energy is then transferred to the light-emitting material, thereby increasing the luminescence efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0459] This is particularly effective when the light-emitting material is a fluorescent material. Furthermore, in order to obtain high luminescence efficiency, it is preferable that the S1 level of the TADF material is higher than that of the fluorescent material. Also, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material.

[0460] Furthermore, it is preferable to use a TADF material that exhibits emission that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows for a smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0461] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To achieve this, it is preferable that the fluorescent material has protecting groups around the luminescent phosphoform (the skeleton that causes luminescence). Preferred protecting groups are substituents without π bonds, saturated hydrocarbons, specifically alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable to have multiple protecting groups. Substituents without π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphoform of the fluorescent material with little effect on carrier transport or carrier recombination. Here, the luminescent phosphoform refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminescent phosphophore preferably has a skeleton containing π bonds, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such luminescent phosphophores include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, phenothiazine skeletons, naphthalene skeletons, anthracene skeletons, fluorene skeletons, chrysene skeletons, triphenylene skeletons, tetracene skeletons, pyrene skeletons, perylene skeletons, coumarin skeletons, quinacridone skeletons, and naphthobisbenzofuran skeletons. Fluorescent materials having naphthalene, anthracene, fluorene, chrysene, triphenylene, tetracene, pyrene, perylene, coumarin, quinacridone, and naphthobisbenzofuran skeletons are particularly preferred due to their high fluorescence quantum yield.

[0462] When using a fluorescent material as the light-emitting material, a material having an anthracene skeleton is preferred as the host material. Using a material having an anthracene skeleton as the host material for a fluorescent material makes it possible to realize a light-emitting layer with good luminescence efficiency and durability. Among the materials having an anthracene skeleton to be used as the host material, materials having a diphenylanthracene skeleton, and especially a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Furthermore, while a carbazole skeleton is preferred as the host material because it improves hole injection and transport, a benzocarbazole skeleton, in which a benzene ring is further condensed into the carbazole skeleton, is even more preferred because the HOMO is about 0.1 eV higher than that of a host material having a carbazole skeleton, making it easier for holes to enter. In particular, a dibenzocarbazole skeleton is preferred as the host material has a HOMO about 0.1 eV higher than that of a host material having a carbazole skeleton, making it easier for holes to enter, as well as excellent hole transport properties and high heat resistance. Therefore, a more preferred host material is a substance having a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or dibenzocarbazole skeleton). Furthermore, from the viewpoint of hole injection and transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton.Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-antryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), 6-[3-(9,10-diphenyl-2-antryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA), and 9-phenyl-10-[4'-(9-phenyl-9H-fluoren-9-yl)biphenyl-4- [Iyl]anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-antryl)ben Examples include zo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviated as βN-mβNPAnth), and 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA). In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices because they exhibit very good properties.

[0463] The host material may be a mixture of multiple substances, and when using a mixed host material, it is preferable to mix an electron-transporting material with a hole-transporting material. By mixing an electron-transporting material with a hole-transporting material, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can also be easily controlled. The weight ratio of the hole-transporting material to the electron-transporting material should be 1:19 to 19:1.

[0464] Furthermore, phosphorescent materials can be used as part of the above-mentioned mixed materials. When a fluorescent material is used as the light-emitting material, the phosphorescent material can be used as an energy donor to supply excitation energy to the fluorescent material.

[0465] Furthermore, these mixed materials may form an excited complex. It is preferable to select a combination that forms an excited complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the luminescent material, as this facilitates smooth energy transfer and efficiently obtains light emission. This configuration is also preferable because it reduces the driving voltage.

[0466] Furthermore, at least one of the materials forming the excitation complex may be a phosphorescent material. By doing so, the triplet excitation energy can be efficiently converted to singlet excitation energy through reverse intersystem crossing.

[0467] For efficient excitation complex formation, it is preferable that the HOMO level of the hole-transporting material is above the HOMO level of the electron-transporting material. Furthermore, it is preferable that the LUMO level of the hole-transporting material is above the LUMO level of the electron-transporting material. The LUMO and HOMO levels of the materials can be derived from the electrochemical properties (reduction potential and oxidation potential) of the materials measured by cyclic voltammetry (CV).

[0468] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above may be read as transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0469] 《Configuration of the electron transport layer》 The electron transport layer (electron transport layer 114, first electron transport layer 114_1, second electron transport layer 114_2) is a layer containing an electron-transporting material. The electron-transporting material has an electron mobility of 1 × 10⁻¹⁰ at an electric field strength [V / cm] square root of 600. −７ cm ２ / Vs or more, preferably 1 x 10 −６ cm ２ A substance having an electron mobility of 1 / Vs or higher is preferred. However, any substance that has higher electron transport capacity than holes can be used. As the above organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As an organic compound having a π-electron-deficient heteroaromatic ring, it is preferable that it be any or more of the following: an organic compound containing a heteroaromatic ring having an azole skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, an organic compound containing a heteroaromatic ring having a diazine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton.

[0470] As an organic compound having electron-transporting properties that can be used in the above-mentioned electron transport layer, any organic compound that can be used as an organic compound having electron-transporting properties in the first layer of the intermediate layer 160 can be used in the same way. In particular, organic compounds containing a heteroaromatic ring having a diazine skeleton, or an organic compound containing a heteroaromatic ring having a pyridine skeleton, or an organic compound containing a heteroaromatic ring having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton, or an organic compound containing a heteroaromatic ring having a triazine skeleton, have high electron-transporting properties and contribute to reducing the driving voltage.

[0471] Furthermore, the electron transport layer has an electron mobility of 1 × 10⁻¹⁰ at an electric field strength [V / cm] square root of 600. −７ cm ２ / Vs or more 5×10 −５ cm ２ It is preferable that the value is less than or equal to / Vs. By reducing the electron transport properties in the electron transport layer, the amount of electrons injected into the light-emitting layer can be controlled, and it is possible to prevent the light-emitting layer from becoming electron-excessive. This configuration is particularly preferable because it results in a good lifetime when the hole injection layer is formed as a composite material and the HOMO level of the material having hole transport properties in the composite material is a material having a relatively low HOMO level of -5.7 eV to -5.4 eV. In this case, it is preferable that the HOMO level of the material having electron transport properties is -6.0 eV or higher.

[0472] For example, heteroaromatic compounds can be used as electron-transporting materials for electron transport layers. A heteroaromatic compound is a cyclic compound containing at least two different elements in its ring structure. The ring structure can include three-membered, four-membered, five-membered, or six-membered rings, but five-membered or six-membered rings are particularly preferred. The elements included are preferably one or more of nitrogen, oxygen, or sulfur in addition to carbon. Nitrogen-containing heteroaromatic compounds (nitrogen-containing heteroaromatic compounds) are particularly preferred, and it is preferable to use electron-transporting materials (electron-transporting materials) such as nitrogen-containing heteroaromatic compounds or π-electron-deficient heteroaromatic compounds containing them. The compound of Embodiment 1 has electron-transporting properties and can therefore be used as an electron-transporting material.

[0473] Furthermore, the electron transport material can be different from the material used for the light-emitting layer. Not all excitons generated by carrier recombination in the light-emitting layer contribute to light emission; some may diffuse into layers adjacent to or near the light-emitting layer. To avoid this phenomenon, it is preferable that the energy level (lowest singlet excitation energy level or lowest triplet excitation energy level) of the material used in the layers adjacent to or near the light-emitting layer is higher than that of the material used for the light-emitting layer. Therefore, by using a different electron transport material than the one used for the light-emitting layer, a highly efficient device can be obtained.

[0474] Heteroaromatic compounds are organic compounds that have at least one heteroaromatic ring.

[0475] Furthermore, a het...

Claims

A display device having a color conversion layer and a light-emitting device, The light-emitting device comprises a first electrode, a second electrode, a light-emitting layer, and a first layer. The light-emitting layer is located between the first electrode and the second electrode, The first layer is located between the light-emitting layer and the second electrode. The first layer comprises a first organic compound, a second organic compound, and either or both a metal and a metal compound. A display device wherein the absorption spectrum of a first mixed film having the first organic compound, the second organic compound, and either or both of the metal and the metal compound has a wavelength region in which the absorption intensity is greater than that of a second mixed film having either the first organic compound and the second organic compound, and either or both of the metal and the metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film. 　 A display device having a color conversion layer and a light-emitting device, The light-emitting device comprises a first electrode, a second electrode, a light-emitting layer, and a first layer. The light-emitting layer is located between the first electrode and the second electrode, The first layer is located between the light-emitting layer and the second electrode. The first layer comprises a first organic compound, a second organic compound, and either or both a metal and a metal compound. The absorption spectrum of a first mixed film having the first organic compound, the second organic compound, and either or both of the metal and the metal compound has a wavelength region in which the absorption intensity is greater than that of a third mixed film having the first organic compound, either or both of the metal and the metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of a fourth mixed film having the second organic compound and either or both of the metal and the metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film. 　 A display device having a color conversion layer and a light-emitting device, The light-emitting device comprises a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer. The first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode. The first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer comprises a first organic compound, a second organic compound, and either or both a metal and a metal compound. A display device wherein the absorption spectrum of a first mixed film having the first organic compound, the second organic compound, and either or both of the metal and the metal compound has a wavelength region in which the absorption intensity is greater than that of a second mixed film having either the first organic compound and the second organic compound, and either or both of the metal and the metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film. 　 A display device having a color conversion layer and a light-emitting device, The light-emitting device comprises a first electrode, a second electrode, a first light-emitting layer, a first layer, and a second light-emitting layer. The first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode. The first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer comprises a first organic compound, a second organic compound, and either or both a metal and a metal compound. The absorption spectrum of a first mixed film having the first organic compound, the second organic compound, and either or both of the metal and the metal compound has a wavelength region in which the absorption intensity is greater than that of a third mixed film having the first organic compound, either or both of the metal and the metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of a fourth mixed film having the second organic compound and either or both of the metal and the metal compound, and having a film thickness that is 10% or less different from the film thickness of the first mixed film. 　 It has a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer. The organic compound layer is located between the first electrode and the second electrode. The second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall. The color conversion layer is located above the second electrode and the partition wall, The partition wall has an inverse tapered shape in cross-section and is conductive. The organic compound layer has a light-emitting layer and a first layer, The light-emitting layer is located between the first electrode and the second electrode, The first layer is located between the light-emitting layer and the second electrode. The first layer is a display device having a first organic compound, a second organic compound, and either a metal or a metal compound, The first mixed film comprises the first organic compound, the second organic compound, and either or both of the metal and the metal compound. The second mixed film has either the first organic compound or the second organic compound, and either or both of the metal and the metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the second mixed film. It has a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer. The organic compound layer is located between the first electrode and the second electrode. The second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall. The color conversion layer is located above the second electrode and the partition wall, The partition wall has an inverse tapered shape in cross-section and is conductive. The organic compound layer has a light-emitting layer and a first layer, The light-emitting layer is located between the first electrode and the second electrode, The first layer is located between the light-emitting layer and the second electrode. The first layer is a display device having a first organic compound, a second organic compound, and either a metal or a metal compound, The first mixed film comprises the first organic compound, the second organic compound, and either or both of the metal and the metal compound. The third mixed film comprises the first organic compound and either or both of the metal and the metal compound, and has a film thickness such that the difference in film thickness from the first mixed film is within 10%. The absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the third mixed film. The fourth mixed film comprises the second organic compound and either or both of the metal and the metal compound, and has a film thickness such that the difference in film thickness from the first mixed film is within 10%. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film. 　 It has a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer. The organic compound layer is located between the first electrode and the second electrode. The second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall. The color conversion layer is located above the second electrode and the partition wall, The partition wall has an inverse tapered shape in cross-section and is conductive. The organic compound layer comprises a first light-emitting layer, a first layer, and a second light-emitting layer. The first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode. The first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer is a display device having a first organic compound, a second organic compound, and either a metal or a metal compound, The first mixed film comprises the first organic compound, the second organic compound, and either or both of the metal and the metal compound. The second mixed film has either the first organic compound or the second organic compound, and either or both of the metal and the metal compound, and has a film thickness that is 10% or less different from the film thickness of the first mixed film. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the second mixed film. 　 It has a first electrode, an organic compound layer, a second electrode, a partition wall, and a color conversion layer. The organic compound layer is located between the first electrode and the second electrode. The second electrode covers the upper surface and edges of the organic compound layer and is in contact with the side surface of the partition wall. The color conversion layer is located above the second electrode and the partition wall, The partition wall has an inverse tapered shape in cross-section and is conductive. The organic compound layer comprises a first light-emitting layer, a first layer, and a second light-emitting layer. The first light-emitting layer and the second light-emitting layer are located between the first electrode and the second electrode. The first layer is located between the first light-emitting layer and the second light-emitting layer. The first layer is a display device having a first organic compound, a second organic compound, and either a metal or a metal compound, The first mixed film comprises the first organic compound, the second organic compound, and either or both of the metal and the metal compound. The third mixed film comprises the first organic compound and either or both of the metal and the metal compound, and has a film thickness such that the difference in film thickness from the first mixed film is within 10%. The absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the third mixed film. The fourth mixed film comprises the second organic compound and either or both of the metal and the metal compound, and has a film thickness such that the difference in film thickness from the first mixed film is within 10%. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film. 　 In claim 1, claim 3, claim 5, or claim 7, A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the absorption spectrum of the second mixed film, in a region with wavelengths longer than the long-wavelength absorption edge of the absorption spectrum of the organic compound film of the second mixed film. 　 In claim 2, claim 4, claim 6, or claim 8, The absorption spectrum of the first mixed film has a wavelength region where the absorption intensity is greater than that of the third mixed film, in a region with wavelengths longer than the long-wavelength absorption edge of the absorption spectrum of the film having the first organic compound. A display device wherein the absorption spectrum of the first mixed film has a wavelength region in which the absorption intensity is greater than that of the fourth mixed film in a region with wavelengths longer than the long-wavelength absorption edge of the absorption spectrum of the film having the second organic compound. 　 In any one of claims 1 to 8, A display device wherein either or both of the aforementioned metal and metal compound are metallic elements belonging to any of the groups from Group 3 to Group 14 of the periodic table. 　 In claim 11, A display device wherein either or both of the metal and the metal compound are metallic elements belonging to Group 3, Group 11, or Group 13 of the periodic table. 　 In any one of claims 1 to 8, It has a second layer, The second layer is located between the first layer and the second electrode. The second layer comprises a third organic compound and a fourth organic compound. The third organic compound is an organic compound or aromatic amine having a π-electron-excess heteroaromatic ring. The fourth organic compound is a display device having at least one halogen group and a cyano group. 　 In any one of claims 1 to 8, A display device wherein the LUMO level of the first organic compound is higher than the LUMO level of the second organic compound. 　 In any one of claims 1 to 8, A display device wherein the HOMO level of the first organic compound is higher than the HOMO level of the second organic compound. 　 In any one of claims 1 to 8, A display device comprising the first organic compound and the second organic compound, each having a heteroaromatic ring. 　 In claim 16, A display device wherein the heteroaromatic ring of the first organic compound and the heteroaromatic ring of the second organic compound each independently contain at least one of the following: a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, and a triazole ring. 　 In claim 16, The first organic compound is a display device having an electron-donating group. 　 In claim 18, A display device in which the electron-donating group is at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

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