Method for manufacturing tandem-type light-emitting device and display apparatus

Abstract

Provided is a method for manufacturing a tandem-type light-emitting device which can be applied to a high-definition display apparatus and has a low drive voltage and good current efficiency. Provided is a method for manufacturing a tandem-type light-emitting device that includes a first light-emitting layer, an intermediate layer, and a second light-emitting layer in an EL layer, wherein: the intermediate layer contains a metal, a first organic compound, and a second organic compound; the first organic compound is an organic compound containing an electron-donating group and a first π-electron deficient heteroaromatic ring; the second organic compound is an organic compound having a second π-electron deficient heteroaromatic ring; and when processing the EL layer into a predetermined shape, an etching solution containing hydrofluoric acid and phosphoric acid and not containing nitric acid is used.

Description

Method for fabricating a tandem light-emitting device and a display device.

[0001] One aspect of the present invention relates to a method for manufacturing a light-emitting device and a display device.

[0002] It should be noted that one aspect of the present invention is not limited to the above-mentioned technical field. Examples of technical fields of one aspect of the present invention include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), methods for driving them, or methods for manufacturing them.

[0003] 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.

[0004] 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.

[0005] The development of light-emitting devices (also called light-emitting elements) is actively progressing as display elements used in display devices. Light-emitting devices that utilize the electroluminescence (EL) phenomenon (also called EL devices or EL elements), especially those using organic compounds in the EL layer, 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.

[0006] To obtain higher-resolution light-emitting devices using organic compounds in the EL layer, research is being conducted on patterning the organic layer using photolithography with photoresists, as an alternative to deposition methods using metal masks. By using photolithography, it is possible to obtain high-resolution display devices with EL layer spacing of several micrometers (see, for example, Patent Document 1).

[0007] Special table 2018-521459 publication

[0008] It has long been known that the EL layer of light-emitting devices using organic compounds in the EL layer is affected by exposure to atmospheric components such as water and oxygen, and it has been common practice to handle them in a near-vacuum environment. In particular, the intermediate layer of light-emitting devices having an electron injection layer or tandem structure uses donor materials such as alkali metals or alkaline earth metals, or compounds thereof. However, these metals and compounds are highly reactive with water or oxygen, and if the surface of the EL layer is exposed to the atmosphere, it deteriorates rapidly and ceases to function as an intermediate layer.

[0009] However, as mentioned above, the photolithography process inevitably requires exposing the surface of the EL layer to the atmosphere. For this reason, it has been difficult to obtain good characteristics in light-emitting devices processed using photolithography. In particular, exposing the surface of the EL layer to the atmosphere often leads to a decrease in the electron injection capacity of the electron injection layer and intermediate layer, resulting in a problem of increased driving voltage.

[0010] Furthermore, when processing using photolithography, wet etching can damage the EL layer with chemicals, potentially causing display defects. These defects can manifest as dark spots or bright spots, or shrinkage of the light-emitting area within a pixel. While minor shrinkage may not be a problem in low-resolution displays, it becomes more pronounced in high-resolution displays.

[0011] Therefore, one aspect of the present invention aims to provide a method for manufacturing a light-emitting device having a tandem structure that is high-resolution and has a suppressed rise in drive voltage. Another aspect of the present invention aims to provide a method for manufacturing a light-emitting device having a tandem structure that is high-resolution, has high display quality, and has a suppressed rise in drive voltage. Another aspect of the present invention aims to provide a method for manufacturing a light-emitting device having a tandem structure that is high-resolution, highly efficient, and has a suppressed rise in drive voltage. Another aspect of the present invention aims to provide a method for manufacturing a light-emitting device having a tandem structure that is high-resolution, highly reliable, and has a suppressed rise in drive voltage. Another aspect of the present invention aims to provide a method for manufacturing a light-emitting device having a tandem structure that is high-resolution, has high display quality, is highly reliable, and has a suppressed rise in drive voltage. Another aspect of the present invention aims to provide a method for manufacturing a light-emitting device having a tandem structure that is high-resolution, has high display quality, is highly efficient, and has a suppressed rise in drive voltage.

[0012] One aspect of the present invention aims to provide a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more) and has suppressed rise in drive voltage. Another aspect of the present invention aims to provide a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more), has high display quality, and has suppressed rise in drive voltage. Another aspect of the present invention aims to provide a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more), has high efficiency, and has suppressed rise in drive voltage. Another aspect of the present invention aims to provide a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more), has high reliability, and has suppressed rise in drive voltage.

[0013] Alternatively, in another aspect of the present invention, the objective is to provide a highly reliable display device. Alternatively, in another aspect of the present invention, the objective is to provide a display device with low power consumption. Alternatively, in another aspect of the present invention, the objective is to provide a high-definition display device. Alternatively, in another aspect of the present invention, the objective is to provide a high-definition and reliable display device. Alternatively, in another aspect of the present invention, the objective is to provide a high-definition and low-power consumption display device.

[0014] Furthermore, the description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily have to solve all of these problems. It is possible to extract other problems from the description in the specification, drawings, and claims.

[0015] One aspect of the present invention is a method for manufacturing a tandem light-emitting device comprising an EL layer containing a first light-emitting layer, an intermediate layer, and a second light-emitting layer, wherein the intermediate layer comprises a metal, a first organic compound, and a second organic compound, the first organic compound being an organic compound containing an electron-donating group and a first π-electron-deficient heteroaromatic ring, and the second organic compound being an organic compound having a second π-electron-deficient heteroaromatic ring, and the method for manufacturing a tandem light-emitting device using an etching solution containing hydrofluoric acid and phosphoric acid but not nitric acid when processing the EL layer into a predetermined shape.

[0016] Alternatively, another aspect of the present invention is a method for manufacturing a tandem light-emitting device comprising: a first step of forming a first electrode; a second step of forming an EL layer on the first electrode; a third step of forming a barrier layer on the EL layer; a fourth step of forming a photomask on the barrier layer; a fifth step of processing the EL layer using the photomask; a sixth step of removing the barrier film to expose the EL layer; and a seventh step of forming a second electrode on the EL layer, wherein the EL layer comprises a first light-emitting layer, an intermediate layer, and a second light-emitting layer, the intermediate layer comprises a metal, a first organic compound, and a second organic compound, the first organic compound being an organic compound comprising an electron-donating group and a first π-electron-deficient heteroaromatic ring, and the second organic compound being an organic compound having a second π-electron-deficient heteroaromatic ring, and the sixth step being an etching solution containing hydrofluoric acid and phosphoric acid but not nitric acid.

[0017] Alternatively, another aspect of the present invention is a display device having a plurality of pixels including a first pixel comprising at least adjacent light-emitting devices A and light-emitting devices B, wherein light-emitting device A comprises a first electrode A, a second electrode A, and an EL layer A located between the first electrode A and the second electrode A, and the EL layer A comprises a first light-emitting layer A, an intermediate layer A, and a second light-emitting layer A, the intermediate layer A located between the first light-emitting layer A and the second light-emitting layer A, and light-emitting device B comprises a first electrode B, a second electrode B, and an EL layer B located between the first electrode B and the second electrode B, the EL layer B comprises a first light-emitting layer B, an intermediate layer B, and a second light-emitting layer B, intermediate Layer B is located between the first light-emitting layer B and the second light-emitting layer B. Intermediate layer A and intermediate layer B each contain a metal, a first organic compound, and a second organic compound. The first organic compound is an organic compound containing an electron-donating group and a first π-electron-deficient heteroaromatic ring. The second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring. The second electrode A and the second electrode B are made of films of the same composition. The first electrode A and the first electrode B, the first light-emitting layer A and the first light-emitting layer B, intermediate layer A and the intermediate layer B, and the second light-emitting layer A and the second light-emitting layer B are all independent of each other. This is a display device in which multiple pixels are arranged at a density of 5000 ppi or more.

[0018] Alternatively, another aspect of the present invention is a display device in which the second electrode A and the second electrode B are formed by a continuous film.

[0019] Alternatively, another aspect of the present invention is a display device in which, in the above configuration, the first π-electron-deficient heteroaromatic ring is a heteroaromatic ring containing two or more pyridine rings.

[0020] Alternatively, in another aspect of the present invention, the first organic compound is a display device having a phenanthroline skeleton.

[0021] Alternatively, another aspect of the present invention is a display device in which, in the above configuration, the first organic compound is an organic compound having an acid dissociation constant pKa of 8 or higher.

[0022] Alternatively, in another aspect of the present invention, the second organic compound is a display device having an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), a triazole ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), or a triazine ring.

[0023] Alternatively, in another aspect of the present invention, the second organic compound is a display device having an acid dissociation constant pKa less than 4.

[0024] Alternatively, another aspect of the present invention is a display device in which, in the above configuration, the metal is a metal belonging to any of Group 3, Group 11, Group 12, or Group 13.

[0025] Alternatively, another aspect of the present invention is a display device in which, in the above configuration, the electron-donating group is one or more of alkyl groups, alkoxy groups, aryloxy groups, alkylamino groups, arylamino groups, and aliphatic cyclic amino groups.

[0026] Alternatively, another aspect of the present invention is a display device in which, in the above configuration, the minimum value of the electrostatic potential of the first organic compound is -0.085 or less when the threshold of the electron density distribution is 0.0004.

[0027] Alternatively, another aspect of the present invention is a display module having the above-described display device and at least one of a connector and an integrated circuit.

[0028] Alternatively, another aspect of the present invention is an electronic device comprising the above-mentioned display module and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0029] Therefore, one aspect of the present invention can provide a method for manufacturing a light-emitting device having a tandem structure that is highly detailed and has a suppressed rise in drive voltage. Another aspect of the present invention can provide a method for manufacturing a light-emitting device having a tandem structure that is highly detailed, has high display quality, and has a suppressed rise in drive voltage. Another aspect of the present invention can provide a method for manufacturing a light-emitting device having a tandem structure that is highly detailed, highly efficient, and has a suppressed rise in drive voltage. Another aspect of the present invention can provide a method for manufacturing a light-emitting device having a tandem structure that is highly detailed, highly reliable, and has a suppressed rise in drive voltage. Another aspect of the present invention can provide a method for manufacturing a light-emitting device having a tandem structure that is highly detailed, has high display quality, is highly reliable, and has a suppressed rise in drive voltage. Another aspect of the present invention can provide a method for manufacturing a light-emitting device having a tandem structure that is highly detailed, has high display quality, is highly efficient, and has a suppressed rise in drive voltage.

[0030] One aspect of the present invention provides a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more) and has a suppressed rise in drive voltage. Another aspect of the present invention provides a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more), has high display quality, and has a suppressed rise in drive voltage. Another aspect of the present invention provides a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more), has high efficiency, and has a suppressed rise in drive voltage. Another aspect of the present invention provides a display device equipped with a light-emitting device having a tandem structure that is highly detailed (5000 ppi or more), has high reliability, and has a suppressed rise in drive voltage.

[0031] Alternatively, according to one aspect of the present invention, a highly reliable display device can be provided. Alternatively, according to one aspect of the present invention, a display device with low power consumption can be provided. Alternatively, according to one aspect of the present invention, a high-definition display device can be provided. Alternatively, according to one aspect of the present invention, a high-definition and reliable display device can be provided. Alternatively, according to one aspect of the present invention, a high-definition and low-power consumption display device can be provided.

[0032] 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.

[0033] Figure 1 is a diagram showing a light-emitting device. Figure 2 is a diagram showing a light-emitting device. Figures 3A and 3B are a top view and a cross-sectional view of the light-emitting device. Figures 4A, 4B, 4C, 4D, and 4E are cross-sectional views showing an example of a method for manufacturing a display device. Figures 5A, 5B, 5C, and 5D are cross-sectional views showing an example of a method for manufacturing a display device. Figures 6A, 6B, 6C, and 6D are cross-sectional views showing an example of a method for manufacturing a display device. Figures 7A, 7B, and 7C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 8A, 8B, and 8C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 9A, 9B, and 9C are cross-sectional views showing an example of a method for manufacturing a display device. Figures 10A and 10B are perspective views showing an example configuration of a display module. Figures 11A and 11B are cross-sectional views showing an example configuration of a display device. Figure 12 is a perspective view showing an example configuration of a display device. Figure 13 is a cross-sectional view showing an example configuration of a display device. Figure 14 is a cross-sectional view showing an example of the configuration of a display device. Figure 15 is a cross-sectional view showing an example of the configuration of a display device. Figures 16A, 16B, 16C, and 16D are diagrams showing an example of electronic equipment. Figures 17A, 17B, 17C, 17D, 17E, and 17F are diagrams showing an example of electronic equipment. Figures 18A, 18B, 18C, 18D, 18E, 18F, and 18G are diagrams showing an example of electronic equipment. Figure 19 is a diagram showing the current density-voltage characteristics of light-emitting device 1 and comparison light-emitting device 1. Figure 20 is a diagram showing the current efficiency-current density characteristics of light-emitting device 1 and comparison light-emitting device 1. Figure 21 is a diagram showing the electroluminescence spectra of light-emitting device 1 and comparison light-emitting device 1. Figures 22A and 22B are optical microscope images of light-emitting device 1 and comparison light-emitting device 1. Figures 23A and 23B are diagrams showing the pixel layout. Figures 24A, 24B, and 24C are top views of the TEG. Figures 25A, 25a, 25B, 25b, 25C, and 25c are top and cross-sectional views of the TEG. Figures 26A and 26B are emission images of a TEG with a resolution of 3027 ppi and a TEG with a resolution of 5009 ppi.Figure 27 shows the current density-voltage characteristics of devices 1 to 3. Figure 28 shows the current efficiency-current density characteristics of devices 1 to 3. Figures 29A, 29B, 29C, and 29D show light emission photographs of a display device with a resolution of 5009 ppi. Figure 30 shows the electroluminescence spectrum of a display device with a resolution of 5009 ppi. Figure 31 shows the chromaticity diagram of a display device with a resolution of 5009 ppi. Figures 32A and 32B show the viewing angle dependence of a display device with a resolution of 5009 ppi. Figures 33A and 33B show screen capture images of a display device with a resolution of 5009 ppi. Figure 34 shows the current density-voltage characteristics of the light-emitting device fabricated in Reference Example 3. Figures 35A and 35B show the relationship between Relative V and film thickness of the light-emitting device fabricated in Reference Example 3. Figure 36 shows the current efficiency-current density characteristics of the light-emitting device fabricated in Reference Example 3. Figures 37A and 37B show the relationship between Relative η and film thickness of the light-emitting device fabricated in Reference Example 3. Figures 38A and 38B show the normalized brightness time variation characteristics of the light-emitting device fabricated in Reference Example 3. Figure 39 shows the LT95 time of the light-emitting device fabricated in Reference Example 3. Figure 40 shows the current density-voltage characteristics of the light-emitting device fabricated in Reference Example 4. Figure 41 shows the current density-voltage characteristics of the light-emitting device fabricated in Reference Example 4. Figure 42 shows the current efficiency-current density characteristics of the light-emitting device fabricated in Reference Example 4. Figures 43A, 43B, 43C, and 43D show the reflected bright-field images of the display device fabricated in Reference Example 2. Figure 44 shows the light-emitting image of the display device fabricated in Reference Example 2. Figures 45A and 45B show the change in the light-emitting area of ​​the display device fabricated in Reference Example 2.

[0034] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that 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 construed as being limited to the descriptions of the embodiments shown below.

[0035] Furthermore, ordinal numbers such as "first," "second," etc., in this specification are added to avoid confusion of constituent elements and do not indicate any order or rank, such as process order or layering order. Even if an ordinal number is not used for a term in this specification, an ordinal number may be used in the claims to avoid confusion of constituent elements. Even if an ordinal number is used for a term in this specification, a different ordinal number may be used in the claims. Even if an ordinal number is used for a term in this specification, the ordinal number may be omitted in the claims.

[0036] In this specification, devices fabricated using a metal mask or FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (metal mask) structured devices. In addition, in this specification, devices fabricated without using a metal mask or FMM may be referred to as MML (metal maskless) structured devices.

[0037] (Embodiment 1) As one method for forming an organic compound film in a predetermined position and shape, vacuum deposition using a metal mask (mask deposition) is widely used. However, with the increasing density and resolution of modern materials, mask deposition is approaching its limits in terms of further resolution due to various reasons, such as alignment accuracy issues and spacing issues between the substrate and the mask.

[0038] On the other hand, photolithography is a processing method that can form denser patterns compared to mask deposition. Furthermore, because photolithography can easily be used for large-area processing, research is progressing on the processing of organic compound films using photolithography as an alternative to mask deposition.

[0039] However, the processing of organic compound films using photolithography presents a significant problem specific to light-emitting devices that use organic compounds in their EL layers. It is known that exposure to atmospheric components such as water and oxygen affects the initial characteristics and reliability of the EL layer of light-emitting devices, and it has been common practice to handle them in a near-vacuum environment. Therefore, processing using photolithography, which includes an atmospheric exposure step, may lead to a degradation of the properties.

[0040] This is especially important to note when fabricating light-emitting devices with a tandem structure. This is because the intermediate layer of a light-emitting device with a tandem structure typically contains a material that acts as a donor to the electron transport material, typically alkali metals or alkaline earth metals, or compounds thereof (hereinafter also referred to as "alkali metal compounds, etc."). These alkali metal compounds, etc. are highly reactive with water or oxygen, so they degrade rapidly not only when directly exposed to the atmosphere, but also when exposed to the atmosphere through multiple organic compound layers, impairing their function as an intermediate layer.

[0041] Therefore, tandem light-emitting devices processed using photolithography had a high driving voltage, making it difficult to obtain good characteristics.

[0042] Furthermore, since photolithography involves an etching process, there are concerns about damage to the EL layer due to exposure to chemicals or etching gases. When wet etching is performed, exposure of the EL layer to chemicals may cause display defects such as bright spots, dark spots, and reduced brightness (shrinkage) around the luminescent areas.

[0043] By processing the EL layer of a light-emitting device using photolithography, it becomes possible to create ultra-high-resolution display devices with resolutions exceeding 5000 ppi. However, the light-emitting area of ​​each pixel in such ultra-high-resolution display devices is extremely small. The shrinkage that is thought to be caused by exposure to the above-mentioned chemical solution originates from the edges of the light-emitting area. Therefore, even a degree of shrinkage that would not be a problem in low-resolution display devices where the ratio of the perimeter of the light-emitting area to the area is small can have a significant impact in high-resolution display devices where the ratio of the perimeter of the light-emitting area to the area is also small. Similarly, the impact of dark spots becomes more significant in high-resolution display devices.

[0044] In contrast, by using a layer in the intermediate layer containing a metal or metal compound, a first organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound containing a second π-electron-deficient heteroaromatic ring, and etching with an aqueous solution containing phosphoric acid and hydrofluoric acid using an etchant, a tandem-type light-emitting device with good properties can be obtained even after a photolithography process involving exposure of the EL layer to air. It is preferable that the etchant does not contain nitric acid. Furthermore, it is preferable that the second organic compound has two or more heteroaromatic rings, and that these two or more heteroaromatic rings are bonded or condensed with each other, resulting in an organic compound having a total of three or more heteroatoms.

[0045] The first organic compound functions as an electron donor for the second organic compound, and the interaction between the first organic compound, the metal, and the second organic compound forms a donor level (a single-occupied molecular orbital (SOMO) or highest-occupied molecular orbital (HOMO) level). The interaction between the first organic compound, the metal, and the second organic compound results in a high-energy donor level (SOMO or HOMO level), which reduces the electron injection barrier from the intermediate layer to the electron transport layer. Furthermore, this interaction allows for the smooth injection and transport of electrons generated in the intermediate layer to the electron transport layer, enabling the fabrication of light-emitting devices with low driving voltages.

[0046] The lowest unoccupied molecular orbital (LUMO) and HOMO 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.

[0047] Furthermore, the SOMO level is an orbital derived from unpaired electrons in the metal, and through the interaction between the metal and the first and second organic compounds, it can also be distributed in the orbitals of the first and second organic compounds. In other words, it can be said that the electron orbitals of the metal and the electron orbitals of the organic compounds are interacting.

[0048] Furthermore, organic compounds containing many interacting atoms can interact with metals more stably. Therefore, the second organic compound is preferably an organic compound that interacts with the metal at two or more dentates. Because organic compounds that interact with metals at multiple dentates are stabilized when they interact with metals, they can form an intermediate layer that is resistant to oxygen and water in the atmosphere, as well as to water and chemicals used in the lithography process. Moreover, in one aspect of the present invention, by using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid) as an etchant, it is possible to provide a display device with good characteristics even for ultra-high-definition displays.

[0049] Preferably, the heteroaromatic ring in the second organic compound is a π-electron-deficient heteroaromatic ring. With this structure, the second organic compound can have electron transport properties, and electrons can be smoothly injected and transported from the intermediate layer to the electron transport layer. Furthermore, if the second organic compound has two or more heteroaromatic rings, and these two or more heteroaromatic rings are bonded or condensed with each other, and have a total of three or more nitrogen atoms, the LUMO level of the second organic compound can be made lower than the LUMO level of the first organic compound. By using a material with a lower LUMO level than the LUMO level of the first organic compound for the second organic compound, the interaction between the p-type layer metal or metal compound, the first organic compound, and the second organic compound can be stabilized, and an intermediate layer that is less prone to degradation even after a photolithography process involving exposure to air can be formed. Therefore, even after a photolithography process involving exposure of the EL layer to the atmosphere, 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 photolithography process. Furthermore, in one aspect of the present invention, by using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid) as the etchant, it is possible to provide a display device with even better characteristics, even for ultra-high-definition display devices.

[0050] Furthermore, the first organic compound preferably has a π-electron-deficient heteroaromatic ring with a lone pair of electrons. This structure allows for stable interaction with p-type layer metals or metal compounds. In addition, the first organic compound preferably has two or more π-electron-deficient heteroaromatic rings with lone pairs of electrons and is a material that interacts with metals at two or more dentates. Organic compounds that interact with metals at two or more dentates are stabilized when they interact with metals, and can form an intermediate layer that is resistant to oxygen and water in the atmosphere, as well as water and chemicals used in the lithography process.

[0051] Furthermore, the first organic compound preferably has electron-donating substituents. With this structure, the first organic compound can have high HOMO and LUMO levels, thereby increasing the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound. Consequently, the interaction between the p-type layer metal or metal compound, the first organic compound, and the second organic compound can be stabilized, and an intermediate layer that is less prone to degradation even after a photolithography process involving exposure to air can be formed. Therefore, even after a photolithography 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 photolithography process.

[0052] Furthermore, the first organic compound preferably has a π-electron-deficient heteroaromatic ring with a lone pair of electrons. This structure allows for stable interaction with metals or metal compounds. Alternatively, the first organic compound preferably has two or more π-electron-deficient heteroaromatic rings with lone pairs of electrons, and is a material that interacts with metals at two or more dentates. Because organic compounds that interact with metals at two or more dentates are stabilized when interacting with metals, they can form an intermediate layer that is resistant to oxygen and water in the atmosphere, as well as water and chemicals used during the lithography process.

[0053] Furthermore, the first organic compound preferably has electron-donating substituents. With this structure, the first organic compound can have high HOMO and LUMO levels, thereby increasing the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound. Consequently, the interaction between the p-type layer metal or metal compound, the first organic compound, and the second organic compound can be stabilized, and an intermediate layer that is less prone to degradation even after a photolithography process involving exposure to air can be formed. Therefore, even after a photolithography 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 photolithography process.

[0054] Furthermore, the region (n-type layer, also called the first region) containing an organic compound having a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound), and a metal or metal compound can be configured in either a mixed layer of the metal or metal compound, the first organic compound, or a laminated structure of a layer containing the metal or metal compound and a layer containing the first organic compound and the second organic compound. When the first region is configured as a laminated structure of a layer containing the metal and the metal or metal compound and a layer containing the first organic compound and the second organic compound, it is preferable that the layer containing the metal or metal compound is on the cathode side, the layers containing the first organic compound and the second organic compound are on the anode side and are laminated in contact with each other, and the layers containing the first organic compound and the second organic compound are in contact with the light-emitting unit on the anode side.

[0055] If the first region is a mixed layer of a metal or metal compound, a first organic compound, and a second organic compound, the number of layers can be reduced compared to a laminated structure, resulting in higher productivity and easier mass production.

[0056] Thus, a tandem-type light-emitting device using a first region comprising a metal or metal compound and an organic compound having a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound), makes it possible to realize a tandem-type light-emitting device with good characteristics even after undergoing a process of atmospheric exposure of the EL layer. In other words, by applying the configuration of one aspect of the present invention, a tandem-type light-emitting device with good characteristics can be realized by a photolithography method that includes an atmospheric exposure process for the EL layer. This makes it possible to provide a display device with extremely high resolution and good characteristics. Furthermore, in one aspect of the present invention, by using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid) as an etchant, it is possible to provide a display device with good characteristics even for an ultra-high-resolution display device.

[0057] An intermediate layer of a light-emitting device according to one aspect of the present invention is a tandem-type light-emitting device having the first region described above. Preferably, the intermediate layer includes a second region which is a p-type layer. A third region may also be provided between the first and second regions. By forming the third region, effects such as smoothing the transfer of electrons between the first and second regions to reduce the driving voltage and reducing the interaction between the first and second regions to improve reliability can be obtained.

[0058] ≪First Region≫ The first region is a region provided on the anode side of the intermediate layer as described above, and includes a metal or metal compound and an organic compound having a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound). The first region is also in contact with the light-emitting unit on the anode side.

[0059] <Metals or Metallic Compounds> As metals or metallic compounds included in the first region, you can use alkali metals (Group 1 elements) such as Li, alkaline earth metals (Group 2 elements) such as Mg and Ca, Group 3 elements including lanthanides such as Y, Eu, and Yb, Group 11 elements such as Cu, Ag, and Au, Group 12 elements such as Zn, earth metals (Group 13 elements) such as Al and In, and metals and compounds of Group 14 elements such as Sn.

[0060] By using alkali metals, alkaline earth metals, and their compounds as the metal, the donor levels formed by the interaction of the first and second organic compounds with each other can be set to high energy levels, allowing electrons generated in the intermediate layer to be smoothly injected and transported to the electron transport layer. This is preferable because it provides a light-emitting device that emits light with a low driving voltage and high efficiency.

[0061] As transition metals, you can use Group 3 elements including lanthanides such as Y, Eu, and Yb; Group 7 elements such as Mn; Group 8 elements such as Fe; Group 9 elements such as Co; Group 10 elements such as Ni and Pt; Group 11 elements such as Cu, Ag, and Au; or compounds thereof. Transition metals are preferred because they have low reactivity with components in the atmosphere such as water and oxygen.

[0062] Among the above, it is more preferable to use metals belonging to the odd-numbered groups (Group 1, Group 3, Group 5, Group 7, Group 9, Group 11, or Group 13). Among these odd-numbered transition metals, metals having one electron (unpaired electron) in their outermost shell orbital are particularly preferred because they readily form SOMO with the first organic compound.

[0063] Furthermore, metals or metal compounds with low melting points that can be deposited by vacuum deposition are preferred because they can easily form mixed layers or laminates with organic compounds. Specifically, for example, metals and metal compounds of Group 11 and Group 13 elements are suitable for use in vacuum deposition because they have low melting points. Also, metals and metal compounds of Group 11 and Group 13 elements are preferred because they are stable in oxygen and water in the atmosphere. For metals or metal compounds that can be deposited by vacuum deposition, the melting point at normal pressure is preferably 2000°C or lower, preferably 1500°C or lower, and more preferably 1000°C or lower, or the sublimation temperature under reduced pressure (vacuum of 1 Pa or less) is preferably 1500°C or lower, preferably 1000°C or lower, and more preferably 500°C or lower.

[0064] Specifically, examples of metals or metal compounds that can be used include lithium, magnesium, calcium, silver, zinc, indium, and their oxides. Even elemental metals may oxidize to form metals or metal compounds during processes such as film formation or exposure to the atmosphere.

[0065] Specifically, preferred metallic materials include, for example, lithium, magnesium, calcium, ytterbium, silver, zinc, aluminum, and indium.

[0066] <First Organic Compound> As the first organic compound, an organic compound having a π-electron-deficient heteroaromatic ring can be used. Furthermore, in order for the first organic compound to interact with the metal and function as an electron donor to the second organic compound, it is preferable that the π-electron-deficient heteroaromatic ring has a lone pair of electrons, and that this lone pair of electrons is electron-donating. That is, it is preferable that the first organic compound has a basic π-electron-deficient heteroaromatic ring. Also, because nitrogen has high electronegativity, it readily interacts with metals. In addition, since nitrogen can form conjugated bonds in organic compounds, by using nitrogen in the molecule, especially in the heteroaromatic ring, it is possible to make an organic compound with high carrier transport properties. Therefore, it is preferable that the first organic compound has a heteroaromatic ring containing nitrogen. It is even more preferable that the heteroaromatic ring is an even-numbered ring, such as a 6-membered ring or an 8-membered ring. With this configuration, the lone pair of electrons on nitrogen does not participate in conjugation, so interaction with the metal is easily generated. Furthermore, in order to smoothly inject and transport electrons from the intermediate layer to the electron transport layer, it is preferable that the first organic compound has electron transport properties. Specifically, for example, it is preferable that the first organic compound has a pyridine ring.

[0067] Furthermore, it is preferable that the first organic compound has two or more π-electron-deficient heteroaromatic rings having lone pairs of electrons, and that these two or more π-electron-deficient heteroaromatic rings are bonded or condensed together. This stabilizes the interaction between the first and second organic compounds and the metal or metal oxide at a bidentate or multidentate level, thus forming an intermediate layer that is less prone to degradation even after a photolithography process involving exposure to air. Therefore, even after a photolithography 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 photolithography process. Specifically, for example, it is preferable that the first organic compound has two or more heteroaromatic rings containing pyridine units. Among these, organic compounds having a bipyridine skeleton are preferred because the nitrogen atom readily coordinates with the metal, thus easily interacting with the metal or metal oxide.

[0068] 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 metals, thus easily interacting with metals or metal oxides.

[0069] Furthermore, the first organic compound 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.

[0070] 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.

[0071] 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.

[0072] Furthermore, it is preferable that the first organic compound has electron-donating substituents. By doing so, the first organic compound can have high HOMO and LUMO levels, which increases the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound. This allows for greater stability when interacting with the metal or metal oxide, the first organic compound, and the second organic compound, and enables the formation of an intermediate layer that is less prone to degradation even after a photolithography process involving exposure to air. Therefore, even after a photolithography 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 photolithography process.

[0073] Furthermore, it is more preferable to use an organic compound having a phenanthroline ring with an electron-donating group as the first organic compound. 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. Moreover, it is preferable that the 1,10-phenanthroline ring has an electron-donating group at at least one of the 4th and 7th positions. 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.

[0074] 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 π-electron-deficient heteroaromatic rings such as phenanthroline rings are not limited to these. Any group that can increase the electron density of a π-electron-deficient heteroaromatic ring by being introduced into it can be used as an electron-donating group. Furthermore, the electron-donating group may be introduced into a π-electron-deficient heteroaromatic ring such as a phenanthroline ring via an arylene group such as a phenylene group, and a p-phenylene group is preferred as the arylene group.

[0075] Alkyl alkyl groups are alkanes (C ｎ H ２ｎ＋２ This 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.

[0076] 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.

[0077] 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.

[0078] 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.

[0079] 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.

[0080] 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. A specific example of such an amino group is the N-methyl-N-phenylamino group.

[0081] 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-26). Heterocyclic amino groups may also have substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0082]

[0083] 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), or (R-21) are more preferred as electron-donating groups. Among these, the groups represented by structural formulas (R-3), (R-4), (R-8), or (R-21) are preferred because they have high electron-donating ability and can further increase the electron density of the phenanthroline ring.

[0084] Furthermore, specific examples of electron-donating groups include the groups represented by the following structural formulas (R-27) and (R-28).

[0085]

[0086] Furthermore, the organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound may have both the electron-donating group described above and other substituents. In addition to the electron-donating group described above, an aryl group is a specific example of a substituent that can be introduced into the π-electron-deficient heteroaromatic ring. Specific examples of aryl groups 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, and 2-fluorenyl group. The aryl group may have further substituents, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0087] Specific examples of organic compounds having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound are shown in structural formulas (100) to (110). However, the organic compounds that can be used as the first organic compound are not limited to these.

[0088]

[0089] Furthermore, it is preferable that the minimum negative value (larger negative absolute value) of the electrostatic potential (ESP) of the first organic compound is small, as this increases the stability of the interaction with the metal. In organic compounds having a π-electron-deficient heteroaromatic ring, the electrostatic potential tends to be negative around the nitrogen atom of the π-electron-deficient heteroaromatic ring. However, by introducing an electron-donating group into the π-electron-deficient heteroaromatic ring, the electrostatic potential around the nitrogen atom of the π-electron-deficient heteroaromatic ring can be further reduced (the negative absolute value can be increased). The electrostatic potential is the interaction energy between a positive point charge with a unit electric charge and the electron distribution of a molecule. The value of the electrostatic potential also changes depending on the threshold of electron density. To improve the efficiency of the interaction with the metal, it is preferable that the minimum value of the electrostatic potential of the first organic compound is smaller (larger negative) than the minimum value of the electrostatic potential of a phenanthroline ring without substituents. Specifically, when the threshold for the electron density distribution is 0.0004, the minimum value of the electrostatic potential is preferably -0.085 or less, and more preferably -0.090 or less. Also, when the threshold for the electron density distribution is 0.003, the minimum value of the electrostatic potential is preferably -0.12 or less, and more preferably -0.13 or less.

[0090] <Second Organic Compound> The first region of the intermediate layer contains a metal or metal compound and the first organic compound, as well as a second organic compound containing a π-electron-deficient heteroaromatic ring. The presence of the second organic compound improves heat resistance and electron transport. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring of the first organic compound is referred to as the first π-electron-deficient heteroaromatic ring, and the π-electron-deficient heteroaromatic ring of the second organic compound is referred to as the second π-electron-deficient heteroaromatic ring, it is preferable that the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different rings.

[0091] Furthermore, as the second π-electron-deficient heteroaromatic ring, preferred are 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 transport properties.

[0092] Furthermore, the second π-electron-deficient heteroaromatic ring may have a fused ring structure.

[0093] As the second organic compound, an organic compound having electron-transporting properties can be used. The electron-transporting organic compound 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 material having an electron mobility of / Vs or higher is preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes.

[0094] 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 These are azole skeletons such as (abbreviated as CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviated as BzOs), and 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviated as ZADN). Organic compounds, 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: 2mDBTBBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 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 [Nyl]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]benzoflo[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 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-(dibenzothiophen-4-yl)phenyl]−[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6 -diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 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-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofl[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 11 Organic compounds having a diazine skeleton such as -[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenantro[9',10':4,5]fl[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnf BPTZn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTZn-02), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCC zPTZn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-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: mDBtBPTZn), 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-triazin-2-yl]-11,12-dihydro-12-phenylindolo[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: mTpBP Tzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz) and other organic compounds having a triazine skeleton are mentioned.,

[0095] Note that as the second organic compound, an organic compound having two or more heteroaromatic rings bonded or condensed to each other and the two or more heteroaromatic rings having a total of three or more heteroatoms is particularly preferable. For example, as the organic compound used for the second organic compound, it is preferable to use an organic compound represented by the following general formula (G1-1) or general formula (G1-2).

[0096]

[0097] In the above general formula (G1-1), A １ , A ２ and A ３ each independently represents a substituted or unsubstituted heteroaromatic ring having from 1 to 30 carbon atoms, A１ A ２ and A ３ They may form fused rings with each other.

[0098] The organic compound represented by general formula (G1-1) has a conjugated double bond in which the nitrogen atoms on the heteroaromatic ring are arranged in the order N-C-C-N, and has the function of interacting with metals at three or more densities. Because organic compounds having such a structure readily interact with metals, they can be suitably used as intermediate layers.

[0099] In the above general formula (G1-1), A １ A ２ and A ３ Examples 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 elements may bond to each other to form a phenanthroline ring.

[0100]

[0101] In the above general formula (G1-2), A1 and A2 each independently represent a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A1 and A2 may form a fused ring with each other, and A1 has 2 or more nitrogen atoms.

[0102] 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.

[0103] 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). ２ Examples 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 ２The 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.

[0104] The following are specific examples of organic compounds having heteroaromatic rings of the general formulas (G1-1) and (G1-2) described above.

[0105]

[0106]

[0107] Furthermore, substituents that can be applied to the above-mentioned general formulas (G1-1) and (G1-2) include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, C6 to C30 aryl groups, C6 to C30 arylene groups, and C1 to C30 heteroaryl groups. Some or all of the hydrogens may be deuterium. Moreover, the groups that can be applied to the above general formulas are not limited to the following specific examples.

[0108] 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.

[0109] 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.

[0110] 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, and the like. 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, and phenyl group.

[0111] Specific examples of arylene groups having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorenine-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 the 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.

[0112] A heteroaryl group having 1 to 30 carbon atoms 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 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 C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, and the like.

[0113] The following are specific examples of organic compounds represented by the general formulas (G1-1) and (G1-2) described above.

[0114]

[0115]

[0116]

[0117] Furthermore, it is more preferable that the LUMO level of the second organic compound is lower than that of the first organic compound. This facilitates the donation of electrons from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. In addition, it is preferable that the second organic compound has electron transport properties, and for this reason, it is also preferable that the LUMO level of the second organic compound is lower than that of the first organic compound.

[0118] Furthermore, it is preferable that the second organic compound has 25 to 100 carbon atoms. By having such a number of carbon atoms, it is possible to create 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.

[0119] Furthermore, it is preferable to use an organic compound with a glass transition temperature Tg of 100°C or higher as the second organic compound. This makes it possible to create an intermediate layer that is less prone to crystallization and has good heat resistance. Therefore, even when processing a portion of the organic compound layer by lithography, it is possible to create a layer that is less prone to crystallization.

[0120] Furthermore, as the second organic compound, an organic compound with an acid dissociation constant pKa less than 4 can be used. By doing so, the solubility of the second organic compound in water can be reduced, thereby increasing its resistance to water and chemicals used in the lithography process.

[0121] Compared to the solubility in water of organic compounds with an acid dissociation constant pKa of 4 or higher, organic compounds with an acid dissociation constant pKa less than 4 have lower solubility in water. Furthermore, compared to using an organic compound with an acid dissociation constant pKa of 4 or higher as the second organic compound, using an organic compound with an acid dissociation constant pKa less than 4 as the second organic compound improves the water resistance of the intermediate layer. In addition, it is possible to suppress the occurrence of defects such as the intermediate layer peeling off from other layers during the manufacturing process. This makes it possible to suppress the occurrence of defects that cause defects in the light-emitting device.

[0122] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTZn-02, BP-BPIcz(II)TZn, etc., can be used as the second organic compound.

[0123] The acid dissociation constant pKa of 4,8mDBtP2Bfpm is 0.60. The acid dissociation constant pKa of 11mDBtBPPnfpr is -1.85. If the acid dissociation constant pKa of an organic compound is unknown, the pKa of each of its skeletons can be investigated, and the largest pKa selected from these can be considered the acid dissociation constant pKa of that organic compound.

[0124] Furthermore, for example, an organic compound having a polarization term δp of 4 or less in the solubility parameter δ can be used as the second organic compound. For instance, the solubility in water of an organic compound having a polarization term δp greater than 4 is lower than that of an organic compound having a polarization term δp greater than 4. Also, compared to using an organic compound having a polarization term δp greater than 4 as the second organic compound, using an organic compound having a polarization term δp of 4 or less as the second organic compound can improve the water resistance of the intermediate layer. In addition, it is possible to suppress the occurrence of defects such as the intermediate layer peeling off from other layers during the photolithography process. This makes it possible to suppress the occurrence of defects that cause defects in the light-emitting device.

[0125] The polarization term δp of the water solubility parameter δ is 16.0 MPa. ０．５ This is described in Japanese Patent Publication No. 2017-173056.

[0126] Organic compounds in which the polarization term δp of the solubility parameter δ has a large difference from the polarization term δp of the solvent, water, are preferable to those with low solubility in water. Therefore, it is preferable to use an organic compound in which the polarization term δp of the solubility parameter δ is 4 or less as the second organic compound.

[0127] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTZn-02, and BP-BPIcz(II)TZn can be used as the second organic compound.

[0128] Furthermore, the polarization term δp of the solubility parameter δ for 8BP-4mDBtPBfpm is 3.5 MPa. ０．５ Therefore, the polarization term δp of the solubility parameter δ for 4,8 mDBtP2Bfpm is 3.4 MPa. ０．５ Therefore, the polarization term δp of the solubility parameter δ for 6BP-4Cz2PPm is 3.4 MPa. ０．５ Therefore, the polarization term δp of the solubility parameter δ of 2mDBTBPDBq-II is 3.2 MPa. ０．５Therefore, the polarization term δp of the solubility parameter δ for 9mDBtBPNfpr is 3.8 MPa. ０．５ Therefore, the polarization term δp of the solubility parameter δ for 11mDBtBPPnfpr is 3.1 MPa. ０．５ Therefore, the polarization term δp of the solubility parameter δ of mPCCzPTZn-02 is 3.5 MPa. ０．５ Therefore, the polarization term δp of the solubility parameter δ of BP-BPIcz(II)TZn is 3.2 MPa. ０．５ That is the case.

[0129] The polarization term δp of the solubility parameter δ was determined using the following calculation method.

[0130] We used Desmond, a classical molecular dynamics simulation software from Schrödinger AG. OPLS2005 was used for the force field. The calculations were performed using an Apollo 6500 from HPE.

[0131] The computational model used a reference cell containing approximately 32 molecules. For each compound, the initial molecular structure was determined by mixing multiple structures with energies close to the most stable structure (singlet ground state) obtained from first-principles calculations in roughly equal proportions, and arranging them randomly to prevent molecular collisions. Subsequently, the structures were randomly moved and rotated using Monte Carlo simulated annealing with OPLS2005 as the force field, thereby moving the molecules. Furthermore, the molecules were moved toward the center of the reference cell to maximize density, resulting in the initial configuration.

[0132] For the first-principles calculations described above, the quantum chemistry calculation software Jaguar was used to calculate the most stable structure in the singlet ground state using density functional theory (DFT). The basis set used was 6-31G**, and the functional was B3LYP-D3. The structure used for the quantum chemistry calculations was sampled by performing conformational analysis using Mixed torsional / Low-mode sampling with the Schrödinger Maestro GUI. The calculations were performed using an HPE Apollo 6500.

[0133] The initial configuration described above was subjected to Brownian motion simulation, followed by NVT ensemble. The ensemble was then treated as NPT, and calculations were performed with a sufficient relaxation time (30 ns) under conditions of 1 atm and 300 K for a step time (2 fs) that reproduces molecular vibrations, to obtain the amorphous solid. The solubility parameter δ of the obtained amorphous solid is defined by the following equation.

[0134]

[0135] Here, ΔHv represents the heat of vaporization, which is obtained by subtracting the total energy of individual molecules averaged over the entire molecular dynamics calculation from the energy of the reference cell; Vm represents the molar volume; R represents the gas constant; and T represents the temperature. Note that the solubility parameter tends to decrease as the difference between the solvent and solute substances increases.

[0136] Furthermore, the solubility parameter δ can be decomposed into a dispersion term δd and a polarization term δp. The dispersion term δd is a term contributed by van der Waals interactions, and the polarization term δp is a term contributed by electrostatic interactions. In particular, the solubility of a solute in water is greatly influenced by the electrostatic interactions that occur between the dipoles of the solute and water molecules. In fact, the solubility of the organic compound that can be used in the second organic compound shows a good correlation with the polarization term δp of the solubility parameter δ obtained by calculation.

[0137] Furthermore, it is more preferable that the LUMO level of the second organic compound is lower than that of the first organic compound. This facilitates the donation of electrons from the donor level formed between the first organic compound and the metal or metal compound to the second organic compound. In addition, it is preferable that the second organic compound has electron transport properties, and for this reason, it is also preferable that the LUMO level of the second organic compound is lower than that of the first organic compound.

[0138] The second organic compound preferably has a LUMO level of -3.0 eV or higher and -2.0 eV or lower, and more preferably -3.0 eV or higher and -2.5 eV or lower. The first organic compound also preferably has a LUMO level of -3.0 eV or higher and -2.0 eV or lower, and more preferably -2.7 eV or higher and -2.0 eV or lower.

[0139] This facilitates the donation of electrons from the donor level formed between the first organic compound and a metal or metallic compound to the second organic compound. Furthermore, this facilitates electron transport by the second organic compound.

[0140] <Second Region> The second region is a p-type layer and is preferably formed from a composite material containing a hole-transporting organic compound (third organic compound) and a material that has electron-accepting properties for the hole-transporting organic compound.

[0141] As a substance that accepts electrons for hole-transporting organic compounds, an organic compound having an electron-withdrawing group (such as a halogen group or a cyano group) can be used, and it is more preferable to use an organic compound having at least one of a halogen group and a cyano group. Specifically, examples include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 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].

[0142] Furthermore, in addition to the organic compounds mentioned above, transition metals or metallic compounds such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used as materials that have electron-accepting properties. In this case, one aspect of the present invention can be described as a light-emitting device having different metals or metallic compounds in the p-type layer and n-type layer of the intermediate layer. Alternatively, it can be described as a light-emitting device having different metals or metallic compounds and organic compounds in the p-type layer and n-type layer. Since metals or metallic compounds are stable, by using metals or metallic compounds in both the p-type layer and the n-type layer, a tandem-type light-emitting device having an intermediate layer that is stable against oxygen and water in the atmosphere, or against water and chemicals during the manufacturing process, can be produced.

[0143] Various organic compounds with hole-transporting properties can be used in composite materials, including 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 used in the composite material 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.

[0144] 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.

[0145] 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)phenyl]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-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis( Examples include 9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, 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, and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine.

[0146] Furthermore, other aromatic amine compounds that possess hole-transporting properties can also be used, 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).

[0147] Furthermore, it is preferable that the material having electron acceptor properties in the p-type layer also has electron-accepting properties. It is also preferable that the material having electron acceptor properties also has electron-accepting properties for organic compounds having hole-transporting properties. Because the material having electron acceptor properties also has electron-accepting properties, charge separation occurs in the p-type layer, allowing it to function as a charge-generating layer, and thus function as a tandem intermediate layer. Furthermore, it is preferable that the p-type layer exhibits a signal observed by electron spin resonance. For example, a spin density of 1 × 10⁻¹⁰ due to a signal observed around a g-value of 2.00 is preferable. 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.

[0148] ≪Third Region≫ Furthermore, a third region may be provided between the first and second regions of the intermediate layer.

[0149] The third region contains an electron-transporting material and has functions such as smoothing the transfer of electrons between the first and second regions to reduce the driving voltage, and reducing the interaction between the first and second regions to improve reliability.

[0150] The LUMO level of the electron-transporting material in the third region is preferably between the LUMO level of the acceptor material in the second region and the LUMO level of the organic compound contained in the layer in contact with the intermediate layer in the anode-side light-emitting unit.

[0151] Furthermore, it is preferable that the specific energy level of the LUMO level in the electron-transporting material used in the third region be -5.0 eV or higher, preferably -5.0 eV to -3.0 eV, more preferably -4.30 eV to -3.00 eV, and more preferably -4.30 eV to -3.30 eV, as this suppresses the increase in the driving voltage. It is preferable that the electron-transporting material used in the third region be a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0152] Specifically, electron-transporting substances used in the third domain include 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), perylenetetracarboxylic acid derivatives such as 3,4,9,10-perylenetetracarboxylic acid diimide (abbreviated as PTCDI), and 3,4,9,10-perylenetetracarboxyl-bis-benzimidazole (abbreviated as PTCBI), as well as (C60-Ih)[5,6]fullerene (abbreviated as C60) and (C70-D5h)[5,6]fullerene (abbreviated as C70). Furthermore, compounds having a heterophan skeleton, which is a cyclophane skeleton containing a heterocycle, can be used, and examples of such compounds include phthalocyanine (abbreviated as H ２Phthalocyanine compounds such as Pc can be used. In addition, metal phthalocyanines containing copper, zinc, cobalt, iron, chromium, nickel, etc., 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), and their derivatives can be used. 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.

[0153] Furthermore, the film thickness of the third region is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less.

[0154] A light-emitting device according to one aspect of the present invention having the above configuration can be made into a light-emitting device with good characteristics even after processing by exposure to the atmosphere or photolithography with exposure to the atmosphere before forming the second electrode. Furthermore, in one aspect of the present invention, by using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid) as an etchant, it is possible to provide a display device with good characteristics even for ultra-high-resolution display devices of, for example, 5000 ppi or more.

[0155] (Embodiment 2) In this embodiment, a light-emitting device used in a display device according to one aspect of the present invention will be described in detail.

[0156] Figure 1 is a schematic diagram of a light-emitting device according to one embodiment of the present invention. The light-emitting device has a first electrode 101 provided on an insulator 100, and an organic compound layer 103 between the first electrode 101 and a second electrode 102. The organic compound layer 103 includes a plurality of light-emitting units (a first light-emitting unit 501 and a second light-emitting unit 502 in Figure 1) and an intermediate layer 116, as described in Embodiment 1.

[0157] The first light-emitting unit 501 has at least a first light-emitting layer 113_1, and the second light-emitting unit 502 has at least a second light-emitting layer 113_2. The first light-emitting layer 113_1 and the second light-emitting layer 113_2 are layers containing a light-emitting material and emit light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0158] The first light-emitting unit 501, as shown in Figure 1, preferably has functional layers such as a hole injection layer 111, a first hole transport layer 112_1, and a first electron transport layer 114_1, in addition to the layers described above. Furthermore, it may also include other functional layers besides those described above, such as an electron blocking layer and an exciton blocking layer. Conversely, it is also possible that none of the layers described above are provided.

[0159] The second light-emitting unit 502, as shown in Figure 1, preferably has functional layers such as a second hole transport layer 112_2, a second electron transport layer 114_2, and an electron injection layer 115, in addition to the layers described above. Furthermore, it may also include other functional layers besides those described above, such as a hole blocking layer, an electron blocking layer, and an exciton blocking layer. Conversely, it is also possible that none of the layers described above are provided.

[0160] Furthermore, the intermediate layer 116 preferably has at least a first region 119, and from the anode (first electrode 101 in Figure 1) side, it has a first region 119, a third region 118, and a second region 117. The first region 119 is a region containing an organic compound having a first π-electron-deficient heteroaromatic ring having an electron-donating group with a metal or metal compound (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound), as described in Embodiment 1. The second region 117 is a layer that generates charge when a voltage is applied. The second region 117 is preferably a layer containing an organic compound having hole-transporting properties and a substance that accepts electrons in the organic compound. The third region 118 is a layer composed of a material having electron-transporting properties and a specific LUMO level, and by providing the third region, the driving voltage of the light-emitting device can be reduced. Furthermore, a decrease in the reliability of the light-emitting device can be suppressed. Furthermore, it can improve the luminous efficiency of light-emitting devices.

[0161] The specific configurations of the first region 119, the second region 117, and the third region 118 were explained in detail in Embodiment 1, so a repetitive explanation will be omitted.

[0162] In this embodiment, it is preferable that the first electrode 101 is an electrode including an anode, and the second electrode 102 is an electrode including a cathode. Furthermore, the first electrode 101 and the second electrode 102 may be formed as a single-layer structure or a laminated structure. If they have a laminated structure, the layer in contact with the organic compound layer 103 functions as the anode or cathode. When the electrodes have a laminated structure, there are no restrictions on the work function of the layers other than the layer in contact with the organic compound layer 103, and materials can be selected according to the required properties such as resistance, ease of processing, reflectivity, light transmittance, and stability.

[0163] 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 silicon oxide (ITSO) containing silicon or silicon oxide, indium zinc oxide, and indium oxide (IWZO) containing tungsten oxide and zinc oxide. These conductive metal or metal compound films are usually deposited 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 as anodes include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), or nitrides of metallic materials (e.g., titanium nitride). Alternatively, a layer of these materials can be used as the anode. For example, a film in which Al, Ti, and ITSO are laminated on Ti is preferred because it has good reflectivity, is highly efficient, and enables high resolution of several thousand ppi. Alternatively, graphene can also be used as a material for the anode. Furthermore, by using a composite material capable of forming the hole injection layer 111 (described later) as the layer in contact with the anode (typically the hole injection layer), it becomes possible to select the electrode material regardless of the work function.

[0164] 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. The hole injection layer 111 contains phthalocyanine (abbreviated as H ２It can be formed from phthalocyanine compounds or complex compounds such as Pc, copper phthalocyanine (abbreviated as CuPc), aromatic amine compounds such as 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), or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviated as PEDOT / PSS).

[0165] Furthermore, the hole injection layer 111 may be formed from a substance having electron-accepting properties. Examples of substances having electron-accepting properties include organic compounds having electron-withdrawing groups (halogen groups, cyano groups, etc.), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 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 complex atoms, such as HAT-CN, are thermally stable and therefore preferred. Furthermore, [3]radialene derivatives having an electron-withdrawing group (especially halogen groups such as fluoro groups, cyano groups, etc.) are preferred because they have very high electron-accepting properties. Specific 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 mentioned above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used as materials that have electron-accepting properties.

[0166] Furthermore, it is preferable that the hole injection layer 111 be formed from a composite material containing the electron-accepting material and an organic compound having hole-transporting properties.

[0167] Various organic compounds with hole-transporting properties can be used in composite materials, including 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 used in the composite material 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.

[0168] 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.

[0169] 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)phenyl]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-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis( Examples include 9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, 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, and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine.

[0170] Furthermore, other aromatic amine compounds that possess hole-transporting properties can also be used, 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).

[0171] 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.

[0172] Furthermore, among materials that possess electron-accepting properties, organic compounds that possess electron-accepting properties are easy to use because they are readily deposited and easy to form films.

[0173] The hole transport layer 112 is 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.

[0174] The above-mentioned hole transporting materials 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), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), and 4-phenyl-3'- (9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 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-9 Compounds having an aromatic amine skeleton such as H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl) Basolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as 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: βNCBP), 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 Lubazole, 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 Compounds having a carbazole skeleton such as '-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylene-2-yl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]phenanthrene (abbreviation: PcPPn), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as 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. Furthermore, the materials listed as having hole-transporting properties used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112.

[0175] The light-emitting layer 113 (first light-emitting layer 113_1, second light-emitting layer 113_2) is a layer having a light-emitting substance, and preferably has both a light-emitting substance and a host material. The light-emitting layer may also contain other materials. Furthermore, it may be a lamination of layers with only different compositional ratios.

[0176] 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.

[0177] 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.

[0178] 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), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (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.

[0179] Also, 5,9-diphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazavolin (abbreviation: DABNA-1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazavolin-3-amine (abbreviation: DABNA-2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazavolin- 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]phenazavolin-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]phenazavolin (abbreviation: Me-tBu4DABNA), N ７ , N ７ , N １３ , N １３ Condensed heteroaromatic compounds containing nitrogen and boron, such as 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[3,2-b]phenazabolin-7,13-diamine (abbreviation: ν-DABNA) and 2-(4-tert-butylphenyl)benz[5,6]indro[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc), particularly compounds having a diazaboranaphtho-anthracene skeleton, can be suitably used because they produce blue emission with a narrow emission spectrum and good color purity.

[0180] In addition to these, there is also 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[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-Y) can be suitably used.

[0181] When phosphorescent materials are used as the light-emitting material in the light-emitting layer, metal complexes, particularly iridium complexes or platinum complexes, are preferred, and examples include the following.

[0182] 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 ]) 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 that use phenylpyridine derivatives having electron-withdrawing groups, such as iridium(III) acetylacetonate (abbreviated as Firaca), as ligands. These compounds exhibit blue phosphorescence and have emission peaks in the wavelength range from 450 nm to 520 nm.

[0183] 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-d ３ -methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d ３ -methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d ３ ) ２ (mbfpypy-d ３ )]), [2-(methyl-d ３ )-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ２ (mbfpypy-d ３ )]), [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)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ２ (mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium (abbreviation: [Ir(ppy) ２In addition to organometallic iridium complexes having a pyridine skeleton such as (mdppy)), there are also (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(tBudppymmtBubiz-tBubb)), [2-(4-(3,5- Organometallic platinum complexes such as 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)), tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ３ Examples include rare earth metal complexes such as (Phen)). These are compounds that 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 because they exhibit outstanding reliability and luminescence efficiency.

[0184] 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 with a pyrazine skeleton yield red emission with good chromaticity.

[0185] In addition to the phosphorescent compounds described above, other known phosphorescent compounds may be selected and used.

[0186] 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 an example of such metal-containing porphyrins, protoporphyrin-tin fluoride complex (SnF) shown in the following structural formula can be 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) and others can also be mentioned.

[0187]

[0188] 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 electron acceptor properties 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, an indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred as the pyrrole skeleton. Furthermore, in a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, both the electron-donating ability of the π-electron-rich heteroaromatic ring and the electron-accepting ability of the π-electron-deficient heteroaromatic ring are strengthened. １ Level and T １ This is particularly preferable because the energy difference between the energy levels becomes small, allowing for efficient acquisition of thermally activated delayed fluorescence. Alternatively, an aromatic ring to which an electron-withdrawing group such as a cyano group is attached 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. Additionally, boron-containing skeletons such as xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, phenylborane, volanthrene, aromatic rings having a nitrile group or cyano group such as benzonitrile or cyanobenzene, heteroaromatic rings, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used as the π-electron-deficient skeleton and the π-electron-rich heteroaromatic ring. Thus, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used instead of at least one of the π-electron-deficient heteroaromatic ring and the π-electron-rich heteroaromatic ring.

[0189]

[0190] Note that TADF material is S １ Level and T １ This material has a small energy level difference and possesses 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.

[0191] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances is S １ Level and T １ It has an extremely small difference from the energy level and functions as a TADF material capable of converting triplet excitation energy into singlet excitation energy.

[0192] Note, - １ As an indicator of the energy level, the phosphorescence spectrum observed at low temperatures (e.g., 77K to 10K) can be used. For TADF materials, draw a tangent line at the short-wavelength tail of its fluorescence spectrum, and the energy at the wavelength of the extrapolation line is S. １ Set the energy level as T, draw a tangent line at the short-wavelength tail of the phosphorescence spectrum, and define the energy of the extrapolation line at the wavelength as T. １ When it is set as a level, that S １ Level and T １ The difference between the energy levels is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0193] Furthermore, when using TADF material as a light-emitting material, the S of the host material １ The level is S of the TADF material. １ A higher level is preferable. Also, the T of the host material １ The level is T of the TADF material. １ A level higher than the current level is preferable.

[0194] 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.

[0195] As materials having hole transport properties, organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton are preferred. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of the following in its ring form is preferred: an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton. Specifically, a carbazole ring, a dibenzothiophene ring, or a ring obtained by further condensing an aromatic ring or heteroaromatic ring with these is preferred.

[0196] 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.

[0197] Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 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: PC Aromatic amines such as BANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirovi[9H-fluoren]-2-amine (abbreviated as PCBASF). Compounds with a skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP), and compounds with a carbazole skeleton, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, organic compounds listed as examples of hole-transporting materials can also be used in the hole transport layer.

[0198] Examples of electron-transporting materials include bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq). ２ Preferably, metal complexes such as bis(2-methyl-8-quinolinolato)(4-phenylphenololato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazollyl)phenololato]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenololato]zinc(II) (abbreviated as ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring are preferred. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring having an azole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0199] Among these, organic compounds containing heteroaromatic rings having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing heteroaromatic rings having a pyridine skeleton, and organic compounds containing heteroaromatic rings having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. Furthermore, benzoflopyrimidine skeletons, benzothienopyrimidine skeletons, benzoflopyrazine skeletons, and benzothienopyrazine skeletons are preferred because they have high electron acceptor properties and good reliability.

[0200] Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton 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- Organic compounds having an azole skeleton, such as 2-yl)phenyl]-9H-carbazole (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), and 3,5-bis[3-(9H-carbazole-9-yl] [3-(3-pyridyl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), vasophenanthroline (abbreviation: Bphen), vasocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1, Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 10-phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthryl)-1-naphthyl]-1,10-phenanthroline (abbreviation: PnNPhen), and 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), 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: 2mDBTPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]Quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]Quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl [Lu-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: 9mDBtBPNF pr), 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 n-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 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-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6( P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 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- Organic compounds having a diazine skeleton, such as 2-(biphenyl-4-yl)-2-phenyl-6-(biphenyl-4-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'-spirobio[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTZn), and 2-{3-[3-(benzo[b]naphtho[1,2-d]f Ran-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), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTZn), 9-[3-(4,6-diphenyl-1,3,5-triazin-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-1,3,5-triazin (abbreviation: mFBPTZn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole Luvasol (abbreviation: mINc(II)PTZn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTZn), 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthryl)phenyl]-4,6-di Phenyl-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- Examples of organic compounds containing heteroaromatic rings having a triazine skeleton include [9-(4,6-diphenyl-1,3,5-triazine-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). Furthermore, organic compounds containing heteroaromatic rings having a diazine skeleton, or heteroaromatic rings having a pyridine skeleton, or heteroaromatic rings having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton, or heteroaromatic rings having a triazine skeleton, exhibit high electron transport properties and contribute to reducing the driving voltage.

[0201] In addition, bipolar organic compounds such as 3,6-bis(diphenylamino)-9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9H-carbazole (abbreviated as DACT-II) and 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq) can also be used.

[0202] 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.

[0203] This is very effective when the above-mentioned luminescent material is a fluorescent luminescent material. Also, in order to obtain high luminescence efficiency in this case, the S of the TADF material １ The energy level is S of the fluorescent material. １ It is preferable that the level be higher than the level. Also, the T of the TADF material １ The energy level is S of the fluorescent material. １ It is preferable that the level be higher than the level of the TADF material. １ The energy level is the T of the fluorescent material. １ A level higher than the current level is preferable.

[0204] 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.

[0205] 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.

[0206] 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 it is preferable for the host material to have a carbazole skeleton because it improves hole injection and transportability, it is even more preferable if it contains a benzocarbazole skeleton in which a benzene ring is further condensed into the carbazole skeleton, because the HOMO level becomes about 0.1 eV shallower than when it contains a carbazole skeleton, making it easier for holes to enter. In particular, when the host material contains a dibenzocarbazole skeleton, it is preferred because the HOMO level becomes about 0.1 eV shallower than when it contains a carbazole skeleton, making it easier for holes to enter, as well as having excellent hole transportability and high heat resistance. Therefore, a more preferred host material is a substance having both 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, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Additionally, it is preferable to include a dibenzofuran skeleton because reliability can be ensured without lowering the T1 level.

[0207] 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' -yl]anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 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.

[0208] 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.

[0209] 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.

[0210] 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.

[0211] 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.

[0212] 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).

[0213] 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.

[0214] Furthermore, it is preferable that the light-emitting layer 113 contains a third organic compound having a third π-electron-deficient heteroaromatic ring as a host material. It is also preferable that the third π-electron-deficient heteroaromatic ring is the same as the second π-electron-deficient heteroaromatic ring contained in the second organic compound included in the first region of the intermediate layer. It is even more preferable that the third organic compound is the same organic compound as the second organic compound.

[0215] The electron transport layer 114 (first electron transport layer 114_1 and second electron transport layer 114_2) is a layer containing an electron-transporting material. The electron-transporting material has an electron mobility of 1 × 10⁻¹⁶ at an electric field strength [V / cm] square root of 600. −７ cm ２ / Vs or more, preferably 1 x 10 −６ cm ２A 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.

[0216] Organic compounds having electron-transporting properties that can be used in the first electron transport layer 114_1 and the second electron transport layer 114_2 can be the same organic compounds that can be used as electron-transporting organic compounds in the first light-emitting layer 113_1 and the second light-emitting layer 113_2. In particular, organic compounds containing a heteroaromatic ring having a diazine skeleton, or 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. Among these, organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen, and mPPhen2P are preferred, and organic compounds having a phenanthroline dimer structure such as mPPhen2P are more preferred due to their superior stability.

[0217] Furthermore, the first electron transport layer preferably contains an organic compound having electron transport properties with an acid dissociation constant pKa of less than 4.

[0218] The first electron transport layer 114_1 and the second electron transport layer 114_2 may have a laminated structure. Furthermore, if the second electron transport layer 114_2 has a laminated structure, the layer in contact with the second light-emitting layer 113_2 may function as a hole-blocking layer. When the electron transport layer in contact with the light-emitting layer functions as a hole-blocking layer, it is preferable to use a material whose HOMO level is 0.5 eV or more deeper than the HOMO level of the material contained in the light-emitting layer.

[0219] Furthermore, the electron transport layer sandwiched between the light-emitting layer and the intermediate layer contains an organic compound having a π-electron-deficient heteroaromatic ring, and it is preferable that the organic compound having the π-electron-deficient heteroaromatic ring is a different organic compound from the organic compound having the π-electron-deficient heteroaromatic ring contained in the aforementioned light-emitting layer. That is, in Figure 1, the first electron transport layer 114_1 contains a fourth organic compound having a π-electron-deficient heteroaromatic ring, and it is preferable that the fourth organic compound is a different organic compound from the third organic compound having a third π-electron-deficient heteroaromatic ring contained in the first light-emitting layer 113_1.

[0220] Between the electron transport layer closest to the second electrode (the second electron transport layer 114_2 in Figure 1) and the second electrode 102, an electron injection layer 115 is provided, which is lithium oxide (Li ２ O), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF) ２ A layer containing an alkali metal or alkaline earth metal or a compound thereof, such as 8-hydroxyquinolinatolithium (abbreviated as Liq), may be provided. The electron injection layer 115 may be a layer made of an electron-transporting material containing an alkali metal or alkaline earth metal or a compound thereof, or an electride may be used. Examples of electrides include a material obtained by adding electrons to a mixed oxide of calcium and aluminum at a high concentration.

[0221] The electron injection layer 115 may be made by using the above-mentioned substances alone, or by incorporating them into a layer made of an electron-transporting substance.

[0222] Furthermore, as the electron injection layer 115, it is also possible to use a layer containing an electron-transporting substance (preferably an organic compound having a bipyridine skeleton) in a concentration (50 wt% or more) of the alkali metal or alkaline earth metal fluoride that results in a microcrystalline state. Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0223] The second electrode 102 is an electrode that includes a cathode. The second electrode 102 may have a layered structure, in which case the layer in contact with the organic compound layer 103 functions as the cathode. As the material forming the cathode, metals, alloys, electrically conductive compounds, and mixtures thereof with a small work function (specifically 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), and elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys (MgAg, AlLi) and compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF)) containing these. ２ Examples include rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer 115 or a thin film of the aforementioned material with a small work function between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, silicon, or indium oxide-tin oxide containing silicon oxide can be used as cathodes, regardless of the magnitude of the work function.

[0224] Furthermore, if the second electrode 102 is formed from a material that is transparent to visible light, the light-emitting device can be made to emit light from the second electrode 102 side, and if the first electrode 101 is formed from a material that is transparent to visible light, the light-emitting device can emit light from the first electrode 101 side.

[0225] These conductive materials can be formed using dry methods such as vacuum deposition or sputtering, inkjet printing, or spin coating. Alternatively, they may be formed using a wet method with a sol-gel process, or a wet method using a metal paste.

[0226] Furthermore, various methods can be used to form the organic compound layer 103, regardless of whether they are dry or wet methods. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating may be used.

[0227] Furthermore, each electrode or layer described above may be formed using different film deposition methods.

[0228] Figure 1 illustrates a light-emitting device having two light-emitting units, but the same principles can be applied to light-emitting devices with three or more stacked light-emitting units. As in the light-emitting device according to this embodiment, by arranging multiple light-emitting units separated between a pair of electrodes by an intermediate layer 116, high-brightness light emission can be achieved while maintaining a low current density, and a long-life element can be realized. Furthermore, a light-emitting device that can be driven at a low voltage and consumes little power can be realized.

[0229] Furthermore, by making the light-emitting colors of each light-emitting unit different, it is possible to obtain a desired color of light emission from the entire light-emitting device. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green light-emitting colors from the first light-emitting unit and blue light-emitting color from the second light-emitting unit.

[0230] Furthermore, each layer, such as the organic compound layer 103, the first light-emitting unit 501, the second light-emitting unit 502, and the charge generation layer, as well as the electrodes, can be formed using methods such as vapor deposition (including vacuum deposition), droplet ejection (also known as inkjet printing), coating, and gravure printing. They may also contain low-molecular-weight materials, medium-molecular-weight materials (including oligomers and dendrimers), or polymer materials.

[0231] Figure 2 shows two adjacent tandem-type light-emitting devices (light-emitting device 130c, light-emitting device 130d) fabricated by photolithography.

[0232] The light-emitting device 130c has an organic compound layer 103c between a first electrode 101c and a second electrode 102 on an insulating layer 175. The organic compound layer 103c has a configuration in which a first light-emitting unit 501c and a second light-emitting unit 502c are stacked with an intermediate layer 116c in between. Although Figure 2 shows an example in which two light-emitting units are stacked, a configuration in which three or more light-emitting units are stacked is also possible. The first light-emitting unit 501c has a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 116c has a second region 117c, a third region 118c, and a first region 119c. The second light-emitting unit 502c includes a second hole transport layer 112c_2, a second light-emitting layer 113c_2, a second electron transport layer 114c_2, and an electron injection layer 115.

[0233] The light-emitting device 130d has an organic compound layer 103d between the first electrode 101d and the second electrode 102 on an insulating layer 175. The organic compound layer 103d has a configuration in which a first light-emitting unit 501d and a second light-emitting unit 502d are stacked with an intermediate layer 116d in between. Although Figure 2 shows an example in which two light-emitting units are stacked, a configuration in which three or more light-emitting units are stacked is also possible. The first light-emitting unit 501d has a hole injection layer 111d, a first hole transport layer 112d_1, a first light-emitting layer 113d_1, and a first electron transport layer 114d_1. The intermediate layer 116d has a second region 117d, a third region 118d, and a first region 119d. The second light-emitting unit 502d includes a second hole transport layer 112d_2, a second light-emitting layer 113d_2, a second electron transport layer 114d_2, and an electron injection layer 115.

[0234] In the light-emitting devices 130c and 130d, the intermediate layers 116c and 116d preferably have at least a first region 119c and a first region 119d, and have the configuration described in Embodiment 1.

[0235] Preferably, the electron injection layer 115 and the second electrode 102 are a continuous, shared layer in the light-emitting devices 130c and 130d. Furthermore, the organic compound layers 103c and 103d other than the electron injection layer 115 are independent of each other because they are processed by photolithography after the formation of the second electron transport layer 114c_2 and after the formation of the second electron transport layer 114d_2, respectively. Also, the edges (contours) of the organic compound layers 103c other than the electron injection layer 115 are processed by photolithography and therefore roughly coincide with the substrate in the direction perpendicular to it. Similarly, the edges (contours) of the organic compound layers 103d other than the electron injection layer 115 are processed by photolithography and therefore roughly coincide with the substrate in the direction perpendicular to it.

[0236] Furthermore, since the second electrodes of the light-emitting devices 130c and 130d are formed simultaneously, they are formed from films of the same composition.

[0237] Furthermore, because the organic compound layer is processed by photolithography, a gap d exists between the organic compound layer 103c and the organic compound layer 103d. Also, the distance between the first electrode 101c and the first electrode 101d can be made smaller than when mask deposition is performed because the organic compound layer is processed by photolithography, and can be set to 0.5 μm or more and 5 μm or less.

[0238] A light-emitting device according to one aspect of the present invention having the above configuration can be made into a light-emitting device with high current efficiency, good reliability, and suppressed rise in drive voltage. Furthermore, in one aspect of the present invention, by using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid) as an etchant, it is possible to provide a display device with good characteristics even for ultra-high-definition display devices.

[0239] Furthermore, while one embodiment of the present invention is particularly suitable for light-emitting devices manufactured through a photolithography process, even light-emitting devices manufactured without a photolithography process exhibit high stability to the atmosphere, resulting in improved yield and cost reduction by eliminating the need for excessively strict atmosphere control during the manufacturing process.

[0240] (Embodiment 3) This embodiment describes a configuration in which a light-emitting device according to one aspect of the present invention is used as a display element for a display device.

[0241] As illustrated in Figures 3A and 3B, multiple light-emitting devices 130 are formed on the insulating layer 175 to constitute a display device.

[0242] The display device has a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixels 178 include sub-pixels 110R, sub-pixels 110G, and sub-pixels 110B.

[0243] In this specification, when describing matters common to, for example, sub-pixels 110R, 110G, and 110B, they may be referred to simply as sub-pixel 110. Similarly, when describing matters common to other components distinguished by letters, the letters may be omitted and the corresponding symbols used.

[0244] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. This allows an image to be displayed on the pixel section 177. In this embodiment, three sub-pixels of red (R), green (G), and blue (B) are used as an example, but combinations of other colors of sub-pixels may also be used. Furthermore, the number of sub-pixels is not limited to three, but may be four or more. Examples of four sub-pixels include four sub-pixels of R, G, B, and white (W), four sub-pixels of R, G, B, and yellow (Y), and four sub-pixels of R, G, B, and infrared (IR).

[0245] In this specification and other documents, the row direction may be referred to as the X direction and the column direction as the Y direction. The X and Y directions intersect, for example, perpendicularly.

[0246] Figure 3A 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. Alternatively, subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0247] A connecting portion 140 and a region 141 may be provided on the outside of the pixel portion 177. The region 141 is provided between the pixel portion 177 and the connecting portion 140. An organic compound layer 103 is provided in the region 141. A conductive layer 151C is provided in the connecting portion 140.

[0248] Figure 3 shows an example where region 141 and connection portion 140 are located to the right of the pixel portion 177, but the positions of region 141 and connection portion 140 are not particularly limited. Also, region 141 and connection portion 140 may be singular or multiple.

[0249] Figure 3B is an example of a cross-sectional view between the dashed line A1-A2 in Figure 3A. As shown in Figure 3A, the display device has an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). The insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach the conductive layer 172, and wiring 176 is provided to fill these openings.

[0250] In the pixel section 177, a light-emitting device 130 is provided on an insulating layer 175 and wiring 176. A protective layer 131 is provided so as to cover the light-emitting device 130. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Preferably, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0251] In Figure 3B, multiple cross-sections of the inorganic insulating layer 125 and the insulating layer 127 are shown, but when the display device is viewed from above, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are connected as one unit. In other words, it is preferable that the insulating layer 127 is an insulating layer having an opening on the first electrode.

[0252] In Figure 3B, the light-emitting device 130 is shown as light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B. Light-emitting devices 130R, 130G, and 130B emit light of different colors from each other. For example, light-emitting device 130R can emit red light, light-emitting device 130G can emit green light, and light-emitting device 130B can emit blue light. In addition, light-emitting devices 130R, 130G, or 130B may emit other visible light or infrared light.

[0253] One embodiment of the present invention can be a top-emission type, for example, which emits light in the opposite direction to the substrate on which the light-emitting device is formed. Alternatively, one embodiment of the present invention may be a bottom-emission type.

[0254] The light-emitting device 130R has the configuration shown in Embodiment 1 and Embodiment 2. The light-emitting device 130R also includes a first electrode 101R (pixel electrode) consisting of a conductive layer 151R and a conductive layer 152R, a first EL layer 104R on the first electrode 101R, an organic compound layer (second EL layer 105 on the first EL layer 104R), and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably located on the second electrode 102 (common electrode) side of the light-emitting layer, and is preferably a hole block layer, a second electron transport layer, or an electron injection layer, or a stack thereof. With this configuration, damage to the light-emitting layer or active layer during the photolithography process can be suppressed, and good film quality and electrical properties can be expected.

[0255] The light-emitting device 130G has the configuration shown in Embodiment 1 and Embodiment 2. The light-emitting device 130G also includes a first electrode 101G (pixel electrode) consisting of a conductive layer 151G and a conductive layer 152G, a first EL layer 104G on the first electrode 101G, a second EL layer 105 on the first EL layer 104G, and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably a hole block layer, a second electron transport layer, or an electron injection layer, or a stack of these.

[0256] The light-emitting device 130B has the configuration shown in Embodiment 1 and Embodiment 2. The light-emitting device 130B includes a first electrode 101B (pixel electrode) consisting of a conductive layer 151B and a conductive layer 152B, a first EL layer 104B on the first electrode 101B, a second EL layer 105 on the first EL layer 104B, and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably a hole block layer, a second electron transport layer, or an electron injection layer, or a stack thereof.

[0257] Of the pixel electrodes (first electrodes) and common electrodes (second electrodes) of the light-emitting device, one functions as the anode and the other as the cathode. In this embodiment, unless otherwise specified, the pixel electrodes function as the anode and the common electrodes function as the cathode.

[0258] The first EL layer 104R, the first EL layer 104G, and the first EL layer 104B are independent island-like layers for each light-emitting device or for each light-emitting color. Preferably, the first EL layer 104R, the first EL layer 104G, and the first EL layer 104B do not overlap with each other. By providing the first EL layer 104 in an island-like manner for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in high-definition display devices. This prevents crosstalk and enables the realization of a display device with extremely high contrast. In particular, it enables the realization of a display device with high current efficiency at low brightness.

[0259] The island-shaped first EL layer 104 can be formed by depositing an EL film and processing the EL using a photolithography method.

[0260] Furthermore, in a display device according to one aspect of the present invention, it is preferable that the first electrode 101 (pixel electrode) of the light-emitting device be in a stacked configuration. For example, in the example shown in Figure 3B, the first electrode 101 of the light-emitting device 130 is in a stacked configuration of a conductive layer 151 provided on the substrate 171 side and a conductive layer 152 provided on the organic compound layer side.

[0261] For example, a metallic material can be used as the conductive layer 151. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used.

[0262] As the conductive layer 152, an oxide having one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing one or more of the following: indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0263] The conductive layer 151 may be a laminated structure of multiple layers having different materials, and the conductive layer 152 may be a laminated structure of multiple layers having different materials. In this case, the conductive layer 151 may have a layer made of a material that can be used for the conductive layer 152, such as a conductive oxide, and the conductive layer 152 may have a layer made of a material that can be used for the conductive layer 151, such as a metallic material. For example, if the conductive layer 151 has a laminated structure of two or more layers, the layer in contact with the conductive layer 152 may be a layer made of a material that can be used for the conductive layer 152.

[0264] Furthermore, it is preferable that the end of the conductive layer 151 has a tapered shape. Specifically, it is preferable that the end of the conductive layer 151 has a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surface of the conductive layer 151 also has a tapered shape. By making the side surface of the conductive layer 152 tapered, the coverage of the first EL layer 104 provided along the side surface of the conductive layer 152 can be improved.

[0265] In one embodiment of the present invention, since the light-emitting device 130 has the configuration shown in Embodiment 1 and Embodiment 2, it is possible to provide a light-emitting device that is excellent in moisture resistance, water resistance, oxygen resistance, and chemical resistance, has a low driving voltage, and has good luminous efficiency.

[0266] Next, an example of a method for manufacturing a display device having the configuration shown in Figure 3A will be explained using Figures 4 to 9.

[0267] [Example of manufacturing method 1] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute a display device can be formed using sputtering, chemical vapor deposition (CVD), vacuum deposition, pulsed laser deposition (PLD), or ALD.

[0268] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by wet film deposition methods such as spin coating, dip coating, spray coating, inkjet printing, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0269] Furthermore, when processing the thin films that make up the display device, the processing can be done using methods such as photolithography.

[0270] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other light sources such as ultraviolet light, KrF laser light, or ArF laser light can also be used. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of the light source for exposure.

[0271] For etching thin films, dry etching, wet etching, or sandblasting methods can be used.

[0272] First, as shown in Figure 4A, an insulating layer 171 is formed on a substrate (not shown). Next, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 so as to cover the conductive layers 172 and 179. Next, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0273] As the substrate, a substrate having at least enough heat resistance to withstand subsequent heat treatment can be used. For example, semiconductor substrates such as glass substrates, quartz substrates, sapphire substrates, ceramic substrates, or organic resin substrates, single-crystal semiconductor substrates made of silicon or silicon carbide, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, and SOI substrates can be used.

[0274] Next, as shown in Figure 4A, openings reaching the conductive layer 172 are formed in the insulating layer 175, insulating layer 174, and insulating layer 173. Subsequently, wiring 176 is formed to fill these openings.

[0275] Next, as shown in Figure 4A, a conductive film 151f, which will later become conductive layers 151R, 151G, 151B, and 151C, is formed on the wiring 176 and the insulating layer 175. For example, a metal material can be used as the conductive film 151f.

[0276] Next, as shown in Figure 4A, a resist mask 191 is formed on the conductive film 151f. The resist mask 191 can be formed by applying a photosensitive material (photoresist), exposing it to light, and developing it.

[0277] Next, as shown in Figure 4B, for example, the conductive film 151f in the region that does not overlap with the resist mask 191 is removed. This forms the conductive layer 151.

[0278] Next, as shown in Figure 4C, the resist mask 191 is removed. The resist mask 191 can be removed, for example, by ashing using oxygen plasma.

[0279] Next, as shown in Figure 4D, insulating film 156f, which will later become insulating layer 156R, insulating layer 156G, insulating layer 156B, and insulating layer 156C, is formed on the conductive layer 151R, conductive layer 151G, conductive layer 151B, conductive layer 151C, and insulating layer 175.

[0280] For the insulating film 156f, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxidative nitride insulating film, or a nitride oxide insulating film, such as silicon oxidative nitride, can be used.

[0281] Next, as shown in Figure 4E, insulating layer 156R, insulating layer 156G, insulating layer 156B, and insulating layer 156C are formed by processing the insulating film 156f.

[0282] Next, as shown in Figure 5A, a conductive film 152f is formed on the conductive layer 151R, conductive layer 151G, conductive layer 151B, conductive layer 151C, insulating layer 156R, insulating layer 156G, insulating layer 156B, insulating layer 156C, and insulating layer 175.

[0283] For example, a conductive oxide can be used as the conductive film 152f. The conductive film 152f may be laminated.

[0284] Next, as shown in Figure 5B, the conductive film 152f is processed to form conductive layers 152R, 152G, 152B, and 152C.

[0285] Next, as shown in Figure 5C, the organic compound film 103Rf is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the insulating layer 175. Note that, as shown in Figure 5C, the organic compound film 103Rf is not formed on the conductive layer 152C.

[0286] Next, as shown in Figure 5C, a sacrificial film 158Rf and a mask film 159Rf are formed.

[0287] By providing a sacrificial film 158Rf on the organic compound film 103Rf, the damage sustained by the organic compound film 103Rf during the manufacturing process of the display device can be reduced, thereby improving the reliability of the light-emitting device.

[0288] For the sacrificial film 158Rf, a film with high resistance to the processing conditions of the organic compound film 103Rf is used, specifically a film with a high etching selectivity ratio with the organic compound film 103Rf. For the mask film 159Rf, a film with a high etching selectivity ratio with the sacrificial film 158Rf is used.

[0289] Furthermore, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat resistance temperature of the organic compound film 103Rf. The substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf is typically 100°C to 200°C, preferably 100°C to 150°C, and more preferably 100°C to 120°C.

[0290] It is preferable to use films that can be removed by wet etching or dry etching for the sacrificial film 158Rf and the mask film 159Rf.

[0291] Furthermore, it is preferable that the sacrificial film 158Rf, which is formed in contact with the organic compound film 103Rf, is formed using a method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, the ALD method (Atomic Layer Deposition method) or vacuum deposition method is preferred over the sputtering method.

[0292] The sacrificial film 158Rf and the mask film 159Rf can be, for example, one or more of the following: a metal film, an alloy film, a metal or metal compound film, a semiconductor film, an organic insulating film, and an inorganic insulating film.

[0293] The sacrificial film 158Rf and the mask film 159Rf can be made of 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. In particular, it is preferable to use low-melting-point materials such as aluminum or silver. It is preferable to use a metallic material capable of shielding ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf, as this can suppress the irradiation of the organic compound film 103Rf with ultraviolet rays during pattern exposure and suppress the degradation of the organic compound film 103Rf.

[0294] Furthermore, the sacrificial film 158Rf and the mask film 159Rf can be made of metals or metal compounds such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), or silicon-containing indium tin oxide, respectively.

[0295] Furthermore, in the above metal or metallic compound, element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium.

[0296] For the sacrificial film 158Rf and the mask film 159Rf, it is preferable to use semiconductor materials such as silicon or germanium, for example, because they have high compatibility with semiconductor manufacturing processes. Alternatively, a compound containing the above semiconductor material can be used.

[0297] Furthermore, various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, oxide insulating films are preferred because they have higher adhesion to the organic compound film 103Rf compared to nitride insulating films.

[0298] Next, as shown in Figure 5C, a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive material (photoresist), followed by exposure and development.

[0299] The resist mask 190R is provided in a position that overlaps with the conductive layer 152R. Preferably, the resist mask 190R is also provided in a position that overlaps with the conductive layer 152C. This helps to suppress damage to the conductive layer 152C during the manufacturing process of the display device.

[0300] Next, as shown in Figure 5D, a portion of the mask film 159Rf is removed using the resist mask 190R to form a mask layer 159R. The mask layer 159R remains on the conductive layer 152R and the conductive layer 152C. After that, the resist mask 190R is removed. Subsequently, the mask layer 159R is used as a mask (also called a hard mask) to remove a portion of the sacrificial film 158Rf to form a sacrificial layer 158R.

[0301] By using the wet etching method, damage to the organic compound film 103Rf during processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to using the dry etching method. When using the wet etching method, for example, an alkaline aqueous solution such as a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), an acidic aqueous solution such as dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof can be used, but it is preferable to perform wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid). By performing wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid), the occurrence of dark spots and shrinkage can be suppressed, making it possible to provide a display device with good characteristics even for ultra-high-definition display devices.

[0302] Furthermore, when using a dry etching method for processing the sacrificial film 158Rf, the degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0303] The resist mask 190R can be removed in the same manner as the resist mask 191.

[0304] Next, as shown in Figure 5D, the organic compound film 103Rf is processed to form the organic compound layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove a portion of the organic compound film 103Rf and form the organic compound layer 103R.

[0305] As a result, as shown in Figure 5D, the laminated structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. The conductive layers 152G and 152B are exposed.

[0306] The organic compound film 103Rf is preferably processed by anisotropic etching. In particular, anisotropic dry etching is preferred. Alternatively, wet etching may be used.

[0307] When using the dry etching method, the degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0308] Furthermore, an etching gas containing oxygen may be used. Including oxygen in the etching gas can increase the etching rate. Therefore, etching can be performed under low power conditions while maintaining a sufficiently fast etching rate. This suppresses damage to the organic compound film 103Rf. Moreover, it suppresses problems such as the adhesion of reaction products generated during etching.

[0309] When using the dry etching method, for example, H ２ CF ４ , C ４ F ８ SF ６ CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing one or more of the Group 18 elements, such as He or Ar, as the etching gas. Alternatively, it is preferable to use a gas containing one or more of these elements and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas.

[0310] Next, as shown in Figure 6A, an organic compound film 103Gf, which will later become the organic compound layer 103G, is formed.

[0311] The organic compound film 103Gf can be formed by the same method as that used to form the organic compound film 103Rf. Furthermore, the organic compound film 103Gf can have the same structure as the organic compound film 103Rf.

[0312] Next, as shown in Figure 6A, a sacrificial film 158Gf and a mask film 159Gf are formed in sequence. After that, a resist mask 190G is formed. The materials and formation methods for the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods for the resist mask 190G are the same as those applicable to the resist mask 190R.

[0313] The resist mask 190G is placed in a position that overlaps with the conductive layer 152G.

[0314] Next, as shown in Figure 6B, a portion of the mask film 159Gf is removed using the resist mask 190G to form a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. After that, the resist mask 190G is removed. Subsequently, a portion of the sacrificial film 158Gf is removed using the mask layer 159G as a mask to form a sacrificial layer 158G. This is preferably done by wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid). This suppresses the occurrence of dark spots and shrinkage, making it possible to provide a display device with good characteristics even for ultra-high-definition display devices.

[0315] Next, the organic compound film 103Gf is processed to form the organic compound layer 103G. As a result, as shown in Figure 6B, a laminated structure of the organic compound layer 103G, sacrificial layer 158G, and mask layer 159G remains on the conductive layer 152G. The mask layer 159R and the conductive layer 152B are exposed.

[0316] Next, as shown in Figure 6C, an organic compound film 103Bf is formed.

[0317] The organic compound film 103Bf can be formed by the same method as that used to form the organic compound film 103Rf. Furthermore, the organic compound film 103Bf can have the same configuration as the organic compound film 103Rf.

[0318] Next, as shown in Figure 6C, a sacrificial film 158Bf and a mask film 159Bf are formed in sequence. After that, a resist mask 190B is formed. The materials and formation methods for the sacrificial film 158Bf and the mask film 159Bf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods for the resist mask 190B are the same as those applicable to the resist mask 190R.

[0319] The resist mask 190B is placed in a position that overlaps with the conductive layer 152B.

[0320] Next, as shown in Figure 6D, a portion of the mask film 159Bf is removed using the resist mask 190B to form a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. After that, the resist mask 190B is removed. Subsequently, a portion of the sacrificial film 158Bf is removed using the mask layer 159B as a mask to form a sacrificial layer 158B. This is preferably done by wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid). By performing wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid), the occurrence of dark spots and shrinkage is suppressed, making it possible to provide a display device with good characteristics even for ultra-high-definition display devices.

[0321] Next, the organic compound film 103Bf is processed to form the organic compound layer 103B. For example, the mask layer 159B and the sacrificial layer 158B are used as a hard mask to remove a portion of the organic compound film 103Bf and form the organic compound layer 103B.

[0322] As a result, as shown in Figure 6D, the laminated structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. In addition, the mask layers 159R and 159G are exposed.

[0323] Furthermore, it is preferable that the sides of the organic compound layer 103R, organic compound layer 103G, and organic compound layer 103B are perpendicular or approximately perpendicular to the surface to be formed. For example, it is preferable that the angle between the surface to be formed and these sides be 60 degrees or more and 90 degrees or less.

[0324] As described above, the distance between two adjacent organic compound layers 103R, 103G, and 103B formed using photolithography can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, this distance can be defined, for example, by the distance between two adjacent opposing ends of organic compound layers 103R, 103G, and 103B. By narrowing the distance between the island-shaped organic compound layers in this way, a display device with high resolution and a large aperture ratio can be provided. Furthermore, the distance between the first electrodes between adjacent light-emitting devices can also be narrowed, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. It is preferable that the distance between the first electrodes between adjacent light-emitting devices is 2 μm or more and 5 μm or less.

[0325] Next, as shown in Figure 7A, it is preferable to remove the mask layer 159R, mask layer 159G, and mask layer 159B.

[0326] The same method as the mask film processing method can be used for the mask layer removal process. In particular, by using a wet etching method, the damage to the organic compound layer 103 during mask layer removal can be reduced compared to when using a dry etching method.

[0327] Alternatively, the mask layer may be removed by dissolving it in a polar solvent such as water or alcohol. Examples of alcohols include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0328] After removing the mask layer, a drying treatment may be performed to remove water adsorbed on the surface. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0329] Next, as shown in Figure 7B, an inorganic insulating film 125f is formed.

[0330] Next, as shown in Figure 7C, an insulating film 127f, which will later become an insulating layer 127, is formed on the inorganic insulating film 125f.

[0331] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0332] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more, and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less, within the above substrate temperature range.

[0333] The inorganic insulating film 125f is preferably formed using, for example, the ALD method. The ALD method is preferable because it can reduce film formation damage and allow for the formation of a film with high coverage. As the inorganic insulating film 125f, for example, it is preferable to form an aluminum oxide film using the ALD method.

[0334] The insulating film 127f is preferably formed using the wet film formation method described above. The insulating film 127f is preferably formed using a photosensitive material, for example, by spin coating, and more specifically, it is preferably formed using a photosensitive resin composition containing an acrylic resin.

[0335] Next, exposure is performed to expose a portion of the insulating film 127f to visible light or ultraviolet light. The insulating layer 127 is formed in the region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C.

[0336] The width of the insulating layer 127 to be formed later can be controlled by the exposure area of ​​the insulating film 127f. In this embodiment, the insulating layer 127 is processed so that it has a portion that overlaps with the upper surface of the conductive layer 151.

[0337] The light used for exposure preferably includes the i-line (wavelength 365 nm). Furthermore, the light used for exposure may also include at least one of the g-line (wavelength 436 nm) and the h-line (wavelength 405 nm).

[0338] Next, as shown in Figure 8A, development is performed to remove the exposed area of ​​the insulating film 127f and form the insulating layer 127a.

[0339] Next, as shown in Figure 8B, etching is performed using the insulating layer 127a as a mask to remove a portion of the inorganic insulating film 125f and thin the film thickness of parts of the sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B. As a result, the inorganic insulating layer 125 is formed beneath the insulating layer 127a. In addition, the surfaces of the thinned portions of the sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B are exposed. In the following, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0340] The first etching process can be carried out by dry etching or wet etching. It is preferable that the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B, as this allows the first etching process to be performed in a single step.

[0341] When performing dry etching, it is preferable to use a chlorine-based gas. Examples of chlorine-based gases include Cl ２ , BCl ３ SiCl ４ , and CCl ４ These can be used individually or in combination of two or more gases. In addition, oxygen gas, hydrogen gas, helium gas, and argon gas, etc., can be added to the chlorine-based gas as appropriate, individually or in combination of two or more gases. By using dry etching, thin areas of the sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B can be formed with good in-plane uniformity.

[0342] As the dry etching apparatus, a dry etching apparatus having a high-density plasma source can be used. A dry etching apparatus having a high-density plasma source can be, for example, an inductively coupled plasma (ICP) etching apparatus. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes can be used.

[0343] Furthermore, it is preferable to perform the first etching process by wet etching. By using the wet etching method, damage to the organic compound layer 103R, organic compound layer 103G, and organic compound layer 103B can be reduced compared to when the dry etching method is used. In this case, wet etching can be performed using a paddle method. It is preferable that the inorganic insulating film 125f is formed using the same material as the sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B, as this allows the above etching process to be performed in a single step. It is preferable to perform the first etching process by wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid). By performing wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid), the occurrence of dark spots and shrinkage can be suppressed, making it possible to provide a display device with good characteristics even for ultra-high-definition display devices.

[0344] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the etching process is stopped when the film thickness is reduced. By leaving the corresponding sacrificial layers 158R, 158G, and 158B on the organic compound layers 103R, 103G, and 103B in this manner, it is possible to prevent damage to the organic compound layers 103R, 103G, and 103B in subsequent processing steps.

[0345] Next, it is preferable to expose the entire substrate to visible light or ultraviolet light and irradiate the insulating layer 127a. The energy density of this exposure is 0 mJ / cm². ２ Even larger, 800 mJ / cm ２ The following is preferable: 0 mJ / cm ２ Larger, 500 mJ / cm ２ The following is more preferable: Performing such exposure after development may improve the transparency of the insulating layer 127a. In addition, it may be possible to lower the substrate temperature required for the heat treatment in a later process to deform the insulating layer 127a into a tapered shape.

[0346] Here, the presence of oxygen barrier insulating layers (for example, an aluminum oxide film) as sacrificial layers 158R, 158G, and 158B reduces the diffusion of oxygen into organic compound layers 103R, 103G, and 103B.

[0347] Next, a heat treatment (also called post-bake) is performed. By performing the heat treatment, the insulating layer 127a can be deformed into an insulating layer 127 having a tapered shape on its side surface (Figure 8C). This heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 130°C. The heating atmosphere may be an atmospheric atmosphere or an inert gas atmosphere. The heating atmosphere may also be an atmospheric pressure atmosphere or a reduced pressure atmosphere. This improves the adhesion between the insulating layer 127 and the inorganic insulating layer 125, and also improves the corrosion resistance of the insulating layer 127.

[0348] In the first etching process, by not completely removing the sacrificial layers 158R, 158G, and 158B, and leaving them in a thinned state, it is possible to prevent the organic compound layers 103R, 103G, and 103B from being damaged and degraded during the heat treatment. Therefore, the reliability of the light-emitting device can be improved.

[0349] Next, as shown in FIG. 9A, using the insulating layer 127 as a mask, an etching process is performed to remove a part of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, openings are formed in the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, respectively, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Hereinafter, this etching process may be referred to as the second etching process.

[0350] The end portion of the inorganic insulating layer 125 is covered with the insulating layer 127. Further, in FIG. 9A, an example is shown in which a part of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered with the insulating layer 127, and the tapered portion formed by the second etching process is exposed.

[0351] The second etching process is performed by wet etching. By using the wet etching method, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced as compared with the case of using the dry etching method. Wet etching can be performed using, for example, an alkaline solution or an acidic solution. It is preferably an aqueous solution so that the organic compound layer 103 does not dissolve. The second etching process is preferably performed by wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid and not containing nitric acid). By performing wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid and not containing nitric acid), the occurrence of dark spots and shrinkage can be suppressed, and a display device with good characteristics can be provided even for an ultra-high-definition display device.

[0352] Subsequently, as shown in FIG. 9B, a second electrode 102 (common electrode) is formed on the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the conductive layer 152C, and the insulating layer 127. The second electrode 102 (common electrode) can be formed by a method such as a sputtering method or a vacuum evaporation method. At this time, as shown in FIG. 3, the organic compound layer 103 may be formed in a stacked structure of the first EL layer 104 and the second EL layer 105, and the second electrode 102 (common electrode) may be formed thereon.

[0353] Subsequently, as shown in FIG. 9C, a protective layer 131 is formed on the second electrode 102 (common electrode). The protective layer 131 can be formed by a method such as a vacuum evaporation method, a sputtering method, a CVD method, or an ALD method.

[0354] Subsequently, a display device can be manufactured by bonding the substrate 120 onto the protective layer 131 using the resin layer 122. As described above, in the method for manufacturing a display device according to an aspect of the present invention, an insulating layer 156 is provided so as to have a region overlapping with the side surface of the conductive layer 151, and a conductive layer 152 is formed so as to cover the conductive layer 151 and the insulating layer 156. Thereby, the yield of the display device can be increased and the occurrence of defects can be suppressed.

[0355] As described above, in the method for manufacturing a display device according to one aspect of the present invention, the island-shaped organic compound layer 103R, the island-shaped organic compound layer 103G, and the organic compound layer 103B are formed not using a fine metal mask, but by processing after the film is deposited on one surface, so that the island-shaped layers can be formed with a uniform thickness. This makes it possible to realize a high-definition display device or a display device with a high aperture ratio. Furthermore, even if the resolution or aperture ratio is high and the distance between subpixels is extremely short, it is possible to suppress contact between the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B in adjacent subpixels. Therefore, it is possible to suppress the generation of leakage current between subpixels. This prevents crosstalk and makes it possible to realize a display device with extremely high contrast. Moreover, by performing the etching of the sacrificial film, mask film, sacrificial layer, and mask by wet etching using an aqueous solution containing phosphoric acid and hydrofluoric acid (preferably an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid), the occurrence of dark spots and shrinkage is suppressed, making it possible to provide a display device with good characteristics even for ultra-high-definition display devices.

[0356] Furthermore, even in display devices having tandem-type light-emitting devices fabricated using photolithography, it is possible to provide light-emitting devices and display devices that are excellent in moisture resistance, water resistance, oxygen resistance, and chemical resistance, have a low driving voltage, and have good luminous efficiency.

[0357] (Embodiment 4) This embodiment describes a display device according to one aspect of the present invention.

[0358] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used, for example, as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as as a display unit for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0359] Furthermore, the display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television equipment, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0360] [Display Module] Figure 10A shows a perspective view of the display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, but may be any of the display devices 100B to 100E described later.

[0361] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0362] Figure 10B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286 composed of multiple wires.

[0363] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of Figure 10B. Various configurations described in the previous embodiment can be applied to the pixels 284a. Figure 10B shows an example where the pixel 284a has a configuration similar to the pixel 178 shown in Figure 3.

[0364] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0365] One pixel circuit 283a is a circuit that controls the driving of multiple elements that a single pixel 284a has.

[0366] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0367] The FPC 290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC 290.

[0368] The display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are stacked on the lower side of the pixel section 284, thereby making it possible to achieve an extremely high aperture ratio (effective display area ratio) for the display section 281.

[0369] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as HMDs or AR devices in the form of glasses. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, enabling a highly immersive display. Furthermore, the display module 280 is not limited to this and can be suitably used in electronic devices having relatively small display parts.

[0370] [Display device 100A] The display device 100A shown in Figure 11A includes a substrate 301, a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a capacitor 240, and a transistor 310.

[0371] The substrate 301 corresponds to the substrate 291 in Figures 10A and 10B. The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, a semiconductor substrate such as a single-crystal silicon substrate can be used. The transistor 310 has a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as a source or drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0372] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0373] Furthermore, an insulating layer 261 is provided to cover the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0374] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0375] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0376] An insulating layer 255 is provided covering the capacitance 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0377] An insulating layer 156R is provided so as to have a region that overlaps with the side surface of the conductive layer 151R, an insulating layer 156G is provided so as to have a region that overlaps with the side surface of the conductive layer 151G, and an insulating layer 156B is provided so as to have a region that overlaps with the side surface of the conductive layer 151B. Furthermore, a conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. A sacrificial layer 158R is located on the organic compound layer 103R, a sacrificial layer 158G is located on the organic compound layer 103G, and a sacrificial layer 158B is located on the organic compound layer 103B.

[0378] The conductive layers 151R, 151G, and 151B are electrically connected to either the source or drain of the transistor 310 by the insulating layers 243, 255, 174, and plugs 256 embedded in the insulating layer 175, the conductive layer 241 embedded in the insulating layer 254, and plugs 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0379] Furthermore, a protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Details of the components from the light-emitting devices 130 to the substrate 120 can be found in Embodiment 3. The substrate 120 corresponds to the substrate 292 in Figure 10A.

[0380] Figure 11B is a modified example of the display device 100A shown in Figure 11A. The display device shown in Figure 11B has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. In the display device shown in Figure 11B, the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light.

[0381] [Display Device 100B] Fig. 12 shows a perspective view of the display device 100B, and Fig. 13 shows a cross-sectional view of the display device 100B.

[0382] The display device 100B has a configuration in which the substrate 352 and the substrate 351 are bonded together. In Fig. 12, the substrate 352 is shown by a dashed line. ​​​​​​​​​​​​​​​​Figure 13 shows an example of a cross-section obtained by cutting a portion of the display device 100B, including a part of the area containing the FPC 353, a part of the circuit 356, a part of the pixel section 177, a part of the connection section 140, and a part of the area including the end.

[0389] [Display device 100C] The display device 100C shown in Figure 13 has a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B, etc., between the substrate 351 and the substrate 352.

[0390] Details of the light-emitting devices 130R, 130G, and 130B can be found in Embodiments 1 to 3.

[0391] Light-emitting device 130R has a conductive layer 224R, a conductive layer 151R on the conductive layer 224R, and a conductive layer 152R on the conductive layer 151R. Light-emitting device 130G has a conductive layer 224G, a conductive layer 151G on the conductive layer 224G, and a conductive layer 152G on the conductive layer 151G. Light-emitting device 130B has a conductive layer 224B, a conductive layer 151B on the conductive layer 224B, and a conductive layer 152B on the conductive layer 151B.

[0392] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The end of the conductive layer 151R is located outside the end of the conductive layer 224R. The insulating layer 156R is provided so as to have a region in contact with the side surface of the conductive layer 151R, and the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R.

[0393] The conductive layers 224G, 151G, 152G, and insulating layer 156G in the light-emitting device 130G, and the conductive layers 224B, 151B, 152B, and insulating layer 156B in the light-emitting device 130B are the same as the conductive layers 224R, 151R, 152R, and insulating layer 156R in the light-emitting device 130R, so a detailed explanation is omitted. The conductive layers 224G, 151G, 152G, 156G, and 152G in the light-emitting device 130G, and the conductive layers 224B, 151B, 152B, 156B, and 152B in the light-emitting device 130B, are the same as the conductive layers 224R, 151R, 152R, 156R, and 152R in the light-emitting device 130R, so a detailed explanation is omitted.

[0394] The conductive layer 224R, conductive layer 224G, and conductive layer 224B have recesses formed to cover the openings provided in the insulating layer 214. Layer 128 is embedded in these recesses.

[0395] Layer 128 has the function of flattening the recesses of conductive layers 224R, 224G, and 224B. Conductive layers 151R, 151G, and 151B are provided on conductive layers 224R, 224G, and 224B and on layer 128, and are electrically connected to conductive layers 224R, 224G, and 224B. Therefore, regions overlapping with the recesses of conductive layers 224R, 224G, and 224B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixels.

[0396] Layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for layer 128 as appropriate. In particular, it is preferable that layer 128 be formed using an insulating material, and especially preferable that it be formed using an organic insulating material. For example, an organic insulating material that can be used for the insulating layer 127 described above can be applied to layer 128.

[0397] A protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. The protective layer 131 and the substrate 352 are bonded via an adhesive layer 142. A light-shielding layer 157 is provided on the substrate 352. A solid sealing structure or a hollow sealing structure can be applied to seal the light-emitting devices 130. In Figure 13, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, indicating a solid sealing structure. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), indicating a hollow sealing structure. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting devices. Furthermore, the space may be filled with a resin different from the adhesive layer 142, which is provided in a frame shape.

[0398] Figure 13 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B; a conductive layer 151C obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B; and a conductive layer 152C obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. Figure 13 also shows an example in which an insulating layer 156C is provided so as to have a region that overlaps with the side surface of conductive layer 151C.

[0399] The display device 100B is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 352. It is preferable to use a material with high transmittance to visible light for the substrate 352. If the light-emitting element emits infrared or near-infrared light, it is preferable to use a material with high transmittance to those. The pixel electrodes contain a material that reflects visible light, and the counter electrodes (second electrodes 102 (common electrodes)) contain a material that transmits visible light.

[0400] On the substrate 351, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0401] It is preferable to use an inorganic insulating film as the insulating layer 211, insulating layer 213, and insulating layer 215.

[0402] An organic insulating layer is preferred for the insulating layer 214, which functions as a planarizing layer.

[0403] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate.

[0404] A connection portion 204 is provided in the region of substrate 351 where substrate 352 does not overlap. At the connection portion 204, the source electrode or drain electrode of transistor 201 is electrically connected to FPC 353 via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. The conductive layer 166 is exposed on the upper surface of the connection portion 204. This allows the connection portion 204 and FPC 353 to be electrically connected via the connection layer 242.

[0405] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 that faces the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, at connection points 140, and in circuits 356, etc. Various optical components can also be arranged on the outside of the substrate 352.

[0406] Materials suitable for use on substrate 120 can be applied to substrate 351 and substrate 352, respectively.

[0407] As the adhesive layer 142, a material that can be used for the resin layer 122 can be applied.

[0408] As the connecting layer 242, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) can be used.

[0409] [Display device 100D] The display device 100D shown in Figure 14 differs from the display device 100C shown in Figure 13 mainly in that it is a bottom-emission type display device.

[0410] The light emitted by the light-emitting device is emitted towards the substrate 351. It is preferable to use a material with high transmittance to visible light for the substrate 351. On the other hand, the light transmittance of the material used for the substrate 352 is not a requirement.

[0411] It is preferable to form a light-shielding layer between the substrate 351 and the transistor 201, and between the substrate 351 and the transistor 205. Figure 14 shows an example in which a light-shielding layer 157 is provided on the substrate 351, an insulating layer 153 is provided on the light-shielding layer, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0412] The light-emitting device 130R includes a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R.

[0413] The light-emitting device 130B includes a conductive layer 112B, a conductive layer 126B on the conductive layer 112B, and a conductive layer 129B on the conductive layer 126B.

[0414] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are made of materials with high transmittance to visible light. It is preferable to use a material that reflects visible light for the second electrode 102 (common electrode).

[0415] Although the light-emitting device 130G is not shown in Figure 14, it is also provided.

[0416] Furthermore, while Figure 14 and others show an example where the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited.

[0417] [Display device 100E] The display device 100E shown in Figure 15 is a modified version of the display device 100C shown in Figure 13, and differs from the display device 100C mainly in that it has a colored layer 132R, a colored layer 132G, and a colored layer 132B.

[0418] In the display device 100E, the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. The colored layers 132R, 132G, and 132B can be provided on the substrate 351 side of the substrate 352. The edges of the colored layer 132R, the edges of the colored layer 132G, and the edges of the colored layer 132B can overlap with the light-shielding layer 157.

[0419] In the display device 100E, the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may also be configured to have the colored layers 132R, 132G, and 132B placed between the protective layer 131 and the adhesive layer 142.

[0420] Figures 13 and 15 show examples where the upper surface of layer 128 has a flat portion, but the shape of layer 128 is not particularly limited.

[0421] 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, these configuration examples can be appropriately combined.

[0422] (Embodiment 5) This embodiment describes an electronic device according to one aspect of the present invention.

[0423] The electronic device of this embodiment has a display device according to one aspect of the present invention in its display unit. The display device according to one aspect of the present invention has high display performance and is easily made high-definition and high-resolution. Therefore, it can be used in the display units of various electronic devices.

[0424] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, and other electronic devices with relatively large screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0425] In particular, a display device according to one aspect of the present invention can be used suitably in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), as well as wearable devices that can be worn on the head, such as VR devices such as head-mounted displays, AR devices such as glasses, and MR devices.

[0426] The electronic device of this embodiment may have sensors (including those with functions to measure force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0427] An example of a wearable device that can be worn on the head will be explained using Figures 16A to 16D.

[0428] The electronic device 700A shown in Figure 16A and the electronic device 700B shown in Figure 16B each include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0429] A display device according to one embodiment of the present invention can be applied to the display panel 751. Therefore, a highly reliable electronic device can be made.

[0430] Electronic devices 700A and 700B can each project an image displayed on the display panel 751 onto the display area 756 of the optical element 753. Because the optical element 753 is translucent, the user can see the image displayed on the display area superimposed on the transmitted image visible through the optical element 753.

[0431] Electronic devices 700A and 700B may be equipped with cameras capable of capturing images of the area in front of them as imaging units. Furthermore, electronic devices 700A and 700B may each be equipped with acceleration sensors such as gyro sensors to detect the orientation of the user's head and display an image corresponding to that orientation in the display area 756.

[0432] The communications unit has a wireless communication device, which can supply, for example, a video signal. Alternatively, instead of the wireless communication device, or in addition to the wireless communication device, it may be equipped with a connector to which a cable for supplying video signals and power potential can be connected.

[0433] Furthermore, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly, wired, or both.

[0434] The housing 721 may be provided with a touch sensor module.

[0435] Various types of touch sensors can be used in the touch sensor module. For example, various methods such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, or optical sensors can be employed. In particular, it is preferable to apply capacitive or optical sensors to the touch sensor module.

[0436] The electronic device 800A shown in Figure 16C and the electronic device 800B shown in Figure 16D each include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0437] A display device according to one embodiment of the present invention can be applied to the display unit 820. Therefore, a highly reliable electronic device can be made.

[0438] The display unit 820 is located inside the housing 821 in a position visible through the lens 832. Furthermore, by displaying different images on a pair of display units 820, a three-dimensional display using parallax can be achieved.

[0439] Preferably, electronic devices 800A and 800B have a mechanism that allows the left and right positions of the lens 832 and the display unit 820 to be in an optimal position according to the user's eye position.

[0440] The attachment portion 823 allows the user to attach the electronic device 800A or the electronic device 800B to their head.

[0441] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras may be provided to accommodate multiple angles of view, such as telephoto and wide-angle.

[0442] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone.

[0443] Electronic devices 800A and 800B may each have input terminals. Cables can be connected to the input terminals to supply video signals from video output devices, etc., and power for charging batteries provided in the electronic devices.

[0444] An electronic device according to one aspect of the present invention may have a function for wireless communication with an earphone 750.

[0445] Furthermore, the electronic device may have an earphone section. The electronic device 700B shown in Figure 16B has an earphone section 727. Some of the wiring connecting the earphone section 727 and the control unit may be located inside the housing 721 or the mounting section 723.

[0446] Similarly, the electronic device 800B shown in Figure 16D has an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be connected to each other by a wire.

[0447] Thus, as one embodiment of the present invention, both eyeglass-type (electronic devices 700A and 700B, etc.) and goggle-type (electronic devices 800A and 800B, etc.) are preferred as electronic devices.

[0448] The electronic device 6500 shown in Figure 17A is a portable information terminal that can be used as a smartphone.

[0449] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0450] A display device according to one embodiment of the present invention can be applied to the display unit 6502. Therefore, a highly reliable electronic device can be made.

[0451] Figure 17B is a schematic cross-sectional view of the housing 6501 including the end on the microphone 6506 side.

[0452] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, and battery 6518 are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0453] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0454] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0455] A display device according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel section, an electronic device with a narrow bezel can be realized.

[0456] Figure 17C shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7171. Here, the housing 7171 is shown supported by a stand 7173.

[0457] A display device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0458] The television device 7100 shown in Figure 17C can be operated using the operation switches on the housing 7171 and a separate remote control unit 7151.

[0459] Figure 17D shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0460] A display device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0461] Figures 17E and 17F show examples of digital signage.

[0462] The digital signage 7300 shown in Figure 17E includes a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0463] Figure 17F shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0464] In Figures 17E and 17F, a display device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0465] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0466] Furthermore, as shown in Figures 17E and 17F, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user.

[0467] The electronic device shown in Figures 18A to 18G includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, a sensor 9007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 9008, and the like.

[0468] The electronic devices shown in Figures 18A to 18G have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, and so on.

[0469] Details of the electronic equipment shown in Figures 18A to 18G will be explained below.

[0470] Figure 18A is a perspective view showing a personal information terminal 9171. The personal information terminal 9171 can be used, for example, as a smartphone. The personal information terminal 9171 may also be equipped with a speaker 9003, a connection terminal 9006, or a sensor 9007. Furthermore, the personal information terminal 9171 can display text and image information on multiple surfaces. Figure 18A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of emails or SNS messages, the sender's name, date and time, time, battery level, signal strength, etc. Alternatively, icons 9050, etc., may be displayed in the position where the information 9051 is displayed.

[0471] Figure 18B is a perspective view showing the personal digital assistant (PDA) 9172. The PDA 9172 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9172, while the PDA 9172 is stored in the breast pocket of their clothing.

[0472] Figure 18C is a perspective view showing the tablet terminal 9173. The tablet terminal 9173 can run various applications, such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The tablet terminal 9173 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000. The left side of the housing 9000 has operation keys 9005 as buttons for operation, and the bottom has connection terminals 9006.

[0473] Figure 18D is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. Charging may be performed by wireless power supply.

[0474] Figures 18E to 18G are perspective views showing a foldable portable information terminal 9201. Figure 18E shows the portable information terminal 9201 in an unfolded state, Figure 18G shows it in a folded state, and Figure 18F shows a perspective view of the state in between, transitioning from one of Figures 18E or 18G to the other. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0475] 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, these configuration examples can be appropriately combined.

[0476] In this example, a tandem-type light-emitting device was prepared by photolithography using an intermediate layer containing a metal or metal compound, a first organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound containing a second π-electron-deficient heteroaromatic ring. The light-emitting device 1, in which the barrier layer was removed using a chemical solution containing phosphoric acid and hydrofluoric acid but not nitric acid, and a comparative light-emitting device 1, in which the barrier layer was removed using a chemical solution containing phosphoric acid, hydrofluoric acid, and nitric acid, were evaluated. The structural formulas of the main compounds used in this example are shown below.

[0477]

[0478] (Method for fabricating the light-emitting device 1) First, a 100 nm layer of silver (Ag) and then a 10 nm layer of indium tin oxide (ITSO) containing silicon dioxide were deposited on a substrate by sputtering. A first electrode 101 was then formed by photolithography in a 2 mm x 2 mm area with a pixel density of 500 ppi. The first electrode 101 was formed in an arrangement that assumed the pixels would have subpixels of three colors: red, green, and blue.

[0479] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0480] After that, approximately 1 x 10 −４ The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for approximately 30 minutes.

[0481] Next, the substrate was fixed to a holder provided in the vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downwards. On the first electrode 101, a hole injection layer 111 was formed by co-depositing N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF), represented by the above structural formula (i), and a fluorine-containing electron-accepting material (OCHD-003) with a molecular weight of 672, in a weight ratio of 1:0.03 (= PCBBiF:OCHD-003) to a thickness of 10 nm to form a hole injection layer 111.

[0482] PCBiF was deposited on the hole injection layer 111 to form a first hole transport layer. The thickness of the first hole transport layer was 57.5 nm.

[0483] Next, a first light-emitting layer was formed on the first hole transport layer by co-depositing 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]fl[2,3-b]pyrazine (abbreviated as 11mDBtBPPnfpr), represented by the above structural formula (ii), PCBiF, and the red phosphorescent material OCPG-006, at a weight ratio of 0.7:0.3:0.05 (=11mDBtBPPnfpr:PCBBiF:OCPG-006) for 40 nm to form the first light-emitting layer.

[0484] Subsequently, 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq), represented by the above structural formula (iii), was deposited to a thickness of 10 nm to form the first electron transport layer.

[0485] After the formation of the first electron transport layer, the second organic compound is 2,2'-([2,2'-bipyridine]-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as 6,6'(P-Bqn)2BPy), represented by the above structural formula (iv), and the first organic compound is 4,7-di(2,3,3a,4,5,6,7,7a-octahydro-1H-isoindole-2-yl)-1,10-phenanthroline (abbreviated as Hid2Phen), represented by the above structural formula (v), and lithium oxide are mixed in a weight ratio of 0.8:0.2:0.05 (=6,6'(P-Bqn)2BPy:Hid2Phen:Li ２ A first region was formed by co-depositing 5 nm of material as shown in (O), a third layer was formed by depositing zinc phthalocyanine (abbreviated as ZnPc) represented by the above structural formula (vi) to a thickness of 2 nm, and then a second layer was formed by co-depositing PCBiF and OCHD-003 to a thickness of 10 nm in a weight ratio of 1:0.15 (= PCBiF:OCHD-003), thereby forming an intermediate layer.

[0486] A second hole transport layer was formed by depositing PCBiF onto the intermediate layer. The thickness of the second hole transport layer was 62.5 nm.

[0487] A second light-emitting layer was formed on the second hole transport layer by co-depositing 11mDBtBPPnfpr, PCBBiF, and OCPG-006 at a weight ratio of 0.7:0.3:0.05 (= 11mDBtBPPnfpr:PCBBiF:OCPG-006) at a thickness of 40 nm.

[0488] Subsequently, 2mPCCzPDBq was deposited to a thickness of 20 nm, and then 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P), represented by the above structural formula (vii), was deposited to a thickness of 25 nm to form a second electron transport layer.

[0489] Here, after opening the glass substrate to the atmosphere, a 30 nm thick aluminum oxide (AlOx) film was deposited as a sacrificial film using the ALD method, with trimethylaluminum (TMA) as the precursor and water vapor as the oxidizing agent.

[0490] Subsequently, a molybdenum (abbreviated as Mo) film was deposited as a mask film to a thickness of 50 nm using the sputtering method. Then, a resist was formed using a photoresist, and the molybdenum was processed into a predetermined shape using lithography to form a mask layer. Specifically, the mask layer was processed to enclose the pixel electrodes by 0.5 μm or more.

[0491] Next, using the mask layer described above, the sacrificial film and the organic compound layer consisting of an electron transport layer, an emissive layer, a hole transport layer, and a hole injection layer were processed into a predetermined shape to form the sacrificial layer and island-shaped organic compound layer. Subsequently, the mask layer was removed by dry etching.

[0492] Next, as a protective layer on the sacrificial layer, a 15 nm thick aluminum oxide film was deposited using the ALD method, with trimethylaluminum (TMA) as the precursor and water vapor as the oxidizer.

[0493] Next, after coating the protective layer with a photosensitive polymer material, a Local Filling Planarization (LFP) structure was formed by removing the photosensitive polymer material in the region overlapping with the first electrode using photolithography, thereby creating an opening.

[0494] Next, after heating at 100°C for 10 minutes in an atmospheric environment, the protective layer and sacrificial layer were removed from the area exposed through the openings formed in the LFP. At this time, the LFP formed from the photosensitive polymer material functions as a resist. The removal of the protective layer and sacrificial layer was performed by wet etching using an aqueous solution containing hydrofluoric acid and phosphoric acid, but not nitric acid. The aqueous solution containing hydrofluoric acid and phosphoric acid was a 1:1 mixture of 0.004% hydrofluoric acid aqueous solution and 0.1% phosphoric acid aqueous solution.

[0495] Next, 1 x 10 −４ The material was subjected to a heat treatment at 80°C for 1.5 hours under vacuum conditions with the internal pressure reduced to approximately Pa. This heat treatment removes moisture and other substances that may have adhered due to the aforementioned processing or exposure to air.

[0496] Subsequently, lithium fluoride (LiF) and ytterbium (Yb) were co-deposited in a volume ratio of 1:0.5 and with a film thickness of 1.5 nm. Then, silver (Ag) and magnesium (Mg) were co-deposited in a volume ratio of 1:0.1 and with a film thickness of 15 nm to form the second electrode 102. Furthermore, PCBiF was deposited on the second electrode 102 as a cap layer with a film thickness of 80 nm to improve the light extraction efficiency.

[0497] Next, in a glove box under a nitrogen atmosphere, the light-emitting device was sealed with a glass substrate to prevent exposure to the atmosphere (applying a UV-curable sealant around the element, irradiating only the sealant with UV light without irradiating the light-emitting device, and heat-treating at 80°C for 1 hour under atmospheric pressure) to form the light-emitting device 1.

[0498] (Method for fabricating comparative light-emitting device 1) Comparative light-emitting device 1 was fabricated in the same manner as light-emitting device 1, except that in the step of removing the protective layer and sacrificial layer in the fabrication method of light-emitting device 1, an aqueous solution containing hydrofluoric acid and nitric acid was used instead of an aqueous solution containing hydrofluoric acid and phosphoric acid but not nitric acid. The amount of nitric acid in the aqueous solution containing hydrofluoric acid and nitric acid was 0.2% or less.

[0499] The device structures of the light-emitting device and the comparative light-emitting device 1 are shown below. Thus, the light-emitting device and the comparative light-emitting device 1 are light-emitting devices that include a metal or metal compound in the first region of the intermediate layer, a first organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound containing a second π-electron-deficient heteroaromatic ring.

[0500]

[0501] The current density-voltage characteristics of the light-emitting device and comparative light-emitting device 1 are shown in Figure 19, the current efficiency-current density characteristics in Figure 20, and the field emission spectra in Figure 21. Furthermore, the current density of the light-emitting device and comparative light-emitting device 1 is 10 mA / cm². ２ Table 6 shows the main characteristics of the sample. Luminance, CIE chromaticity, and field emission spectrum were measured using a spectroradiometer (Topcon SR-UL1R) at room temperature.

[0502]

[0503] From Figures 20, 21, and Table 2, it was found that there were no significant differences in efficiency and emission spectrum between the light-emitting device and the comparative light-emitting device 1, indicating that both are tandem-type light-emitting devices with good current efficiency. On the other hand, from the current density-voltage characteristics in Figure 19, it was found that there is a difference in driving voltage between the light-emitting device 1 and the comparative light-emitting device 1.

[0504] Furthermore, Figure 22A shows a reflected bright-field image of light-emitting device 1, and Figure 22B shows a reflected bright-field image of comparative light-emitting device 1, observed with an optical microscope at 100x objective lens magnification. From Figures 22A and 22B, it can be seen that while comparative light-emitting device 1 exhibits unevenness and black spots within the light-emitting region, no such defects are observed in light-emitting device 1. Thus, it was found that light-emitting device 1 suppresses the occurrence of unevenness and black spots, and is a light-emitting device capable of providing a display device with good display quality.

[0505] In other words, in a tandem-type light-emitting device in which an intermediate layer is made containing a metal or metal compound, a first organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound containing a second π-electron-deficient heteroaromatic ring, and the organic compound layer is processed by photolithography, it was found that light-emitting device 1, in which the barrier layer was removed using a chemical solution containing phosphoric acid and hydrofluoric acid but not nitric acid, is a light-emitting device with better characteristics than comparative light-emitting device 1, in which the barrier layer was removed using a chemical solution containing phosphoric acid, hydrofluoric acid and nitric acid.

[0506] Furthermore, the light-emitting device 1 and the comparative light-emitting device 1 are manufactured to have a pixel density of 500 ppi. Therefore, the effects of unevenness and black spots occurring in the comparative light-emitting device 1 are minor. However, in light-emitting devices used in ultra-high-definition display devices with a resolution of 5000 ppi or higher, these effects become more serious because the area of ​​the light-emitting region becomes very small. For this reason, one aspect of the present invention can be more suitably used in ultra-high-definition display devices with a resolution of 5000 ppi or higher.

[0507] (Reference Example 1) This reference example describes the results of a TEG (Test Element Group) that was fabricated and examined for a display device with a resolution of 5000 ppi or higher.

[0508] First, Figures 23A and 23B show pixel layouts for display devices with pixel densities of 3207 ppi and 5009 ppi, respectively. Both layouts use the same design rules, with a gap of 1.09 μm between subpixels. The aperture ratio in the 3207 ppi pixel layout in Figure 23A is 56.6% (R: 11.8%, G: 18.9%, B: 25.9%), and the aperture ratio in the 5009 ppi pixel layout in Figure 23B is 37.2% (R: 7.8%, G: 12.4%, B: 17.0%). The area ratio of each subpixel was designed to be the same for both the 3207 ppi and 5009 ppi layouts.

[0509] Figure 24A shows the arrangement of the fabricated TEGs. Eight TEGs were formed on a 5-inch substrate 400, each containing six devices 401 (two each of the red device 401R, green device 401G, and blue device 401B). Note that 402 is the region for connecting to the cathode.

[0510] Region 403 is the area where the light-emitting device emits light. The area of ​​region 403 is 2 mm x 2 mm.

[0511] Within and around this region 403, pixels having the layout shown in Figure 23A or Figure 23B are arranged in a matrix, and each light-emitting device is formed with a pixel density corresponding to a display device of 3207 ppi or 5009 ppi. The region 404, which is 1 mm or more around the region 403, is a region in which the same pixel pattern as region 403 is formed but without being connected to wiring (see Figure 24C).

[0512] Figure 24B is an enlarged view of a portion of Figure 24A. Figure 25a shows a cross-sectional view of the red device 401R along A-A'' shown in Figure 24B, Figure 25b shows a cross-sectional view of the green device 401G along B-B'', and Figure 25c shows a cross-sectional view of the blue device 401B along C-C''.

[0513] Furthermore, Figures 25A to 25C are top views of one pixel in each device 401, where the cross section A-A' in Figure 25A corresponds to A-A' in Figure 25a, the cross section B-B' in Figure 25B corresponds to B-B' in Figure 25b, and the cross section C-C' in Figure 25C corresponds to C-C' in Figure 25c.

[0514] As shown in Figures 25A and 25a, the red device 401R has wiring 176 for connecting to the conductive layer 172 only on the first electrode of the light-emitting device corresponding to the red sub-pixel 110R. Similarly, as shown in Figures 25B and 25b, the green device 401G has wiring 176 for connecting to the conductive layer 172 only on the first electrode of the light-emitting device corresponding to the green sub-pixel 110G, and as shown in Figures 25C and 25c, the blue device 401B has wiring 176 for connecting to the conductive layer 172 only on the first electrode of the light-emitting device corresponding to the blue sub-pixel 110B. Note that no wiring 176 is provided in region 404.

[0515] The organic compound layer 103 was processed by photolithography. The sacrificial layer and protective layer were etched using an aqueous solution containing hydrofluoric acid and nitric acid.

[0516] Figures 26A and 26B show light emission images of the green device 401G observed with an optical microscope at 100x objective lens magnification. The light emission images were taken using an OLYMPUS MX61L optical microscope and an OLYMPUS DP74 CCD camera (image resolution: 1600 x 1200 pixels). Figure 26A is an image of a TEG device (device 2) fabricated with a pixel density equivalent to 3207 ppi using the pixel layout shown in Figure 23A, and Figure 26B is an image of a TEG device (device 1) fabricated with a pixel density equivalent to 5009 ppi using the pixel layout shown in Figure 23B. As can be seen, the light emission area of ​​the subpixels arranged at a pixel density of 5009 ppi is very small compared to 3207 ppi, but both were patterned without any problems. Device 3 is a TEG device in which the EL layer has not been etched.

[0517] Figure 27 shows the current density-voltage characteristics of devices 1, 2, and 3, and Figure 28 shows the current efficiency-current density characteristics. Note that device 3 is a test piece in which the region 403 is a single light-emitting device without patterning of the first electrode 101 and the organic compound layer 103.

[0518] (Reference Example 2) This reference example shows the results of an investigation into the light emission characteristics of a 5009 ppi display device that was fabricated.

[0519] The fabricated display device has a screen size of 1.02 inches diagonally, a resolution of 3600 x 3600, a pixel size of 5.07 μm x 5.07 μm, a pixel density of 5009 ppi, and an aperture ratio of 39.1%, with the pixel arrangement shown in Figure 23B.

[0520] The organic compound layer was fabricated using photolithography, and the light-emitting device is a top-emission type light-emitting device with a two-stage tandem structure having two light-emitting layers of the same color. The sacrificial layer and protective layer were etched using an aqueous solution containing hydrofluoric acid and nitric acid.

[0521] Figure 29A shows the emission images observed with an optical microscope at 100x objective lens when only the red subpixel is illuminated, Figure 29B shows the emission images when only the green subpixel is illuminated, Figure 29C shows the emission images when only the blue subpixel is illuminated, and Figure 29D shows the emission images when all three subpixels are illuminated. Thus, it was found that processing can be performed without problems even with a display device with a resolution of 5009 ppi.

[0522] Next, Figure 30 shows the electroluminescence spectra of each color at high and low brightness levels. This shows that the emission spectrum of the display device in this reference example does not change with brightness, and that it exhibits high color purity in all cases. Furthermore, it was found that even at a resolution of 5009 ppi, no leakage to adjacent pixels was observed, and good color purity emission was obtained.

[0523] Figure 31 also shows the chromaticity (x, y) of the red, green, and blue light emitted from this display device in CIE 1931 chromaticity coordinates (xy chromaticity coordinates). The measurements were performed using a spectroradiometer (Topcon Techno House: SR-LEDW-5N). Figure 31 also shows the DCI-P3 (Digital Cinema Initiatives P3) color gamut (thick solid line). This shows that this display device has a DCI-P3 standard coverage of 100% or more.

[0524] The measurement conditions were as follows: brightness of approximately 862 cd / m² on the display unit.２ The brightness values ​​for red, green, and blue were used when displaying white light, and measurements were taken by displaying either red, green, or blue as a single color.

[0525] Next, to evaluate the viewing angle dependence of the display device's chromaticity, the chromaticity was measured at multiple angles. An imaging colorimeter (Konica Minolta, ProMetric® IC-PMI29) was used for the measurements. In this example, the direction perpendicular to the display surface of the display device was defined as 0°, and measurement results from -15° to 15° were used. The measurement direction is shown in the schematic diagram in Figure 32A. Figure 32A shows the positional relationship between the photodetector and the pixels.

[0526] From the measurement results, chromaticity (x, y) was obtained at each angle. Next, using the obtained chromaticity (x, y), chromaticity (u', v') in the CIE 1976 chromaticity coordinate system (u'v' chromaticity coordinate system) was calculated. Then, the chromaticity difference (Δu'v') from the chromaticity in the front direction (chromaticity at 0°) was calculated for each angle. Note that Δu'v' at 0° is 0. The larger Δu'v', the greater the chromaticity difference from the front (0°) at that angle.

[0527] Figure 32B shows the viewing angle dependence of the chromaticity difference Δu'v' in the monochromatic displays of red, green, and blue. The thick dashed line indicates Δu'v' = 0.02, which is the guideline for the visual limit of color shift as defined in JIS Z 8518.

[0528] As shown in Figure 32B, Δu'v' was small for each color, indicating good viewing angle dependence of the display device's chromaticity. In particular, within the range of ±15° for red, and ±15° for green and blue, Δu'v' was less than 0.02, which is considered the limit of human visibility, suggesting that color shift is hardly noticeable.

[0529] Figures 33A and 33B show photographs of the display of this device. As shown, this device is capable of displaying images with an ultra-high resolution of 5009 ppi without any major problems.

[0530] Furthermore, we investigated the change in the light-emitting area of ​​the fabricated display device over time. The investigation method is described below.

[0531] First, the specified values ​​for the light-emitting area of ​​each subpixel were calculated. The light-emitting area was estimated by filling in the outline of the light-emitting portion of a bright-field reflected image obtained using an optical microscope, as shown in Figure 43A, with the color of each subpixel, as shown in Figure 43B, and calculating the area (number of pixels). This was then used as the specified value for the light-emitting area of ​​each subpixel. For clarity, Figure 43C is an image in which areas other than those filled with each color are filled with black, and Figure 43D is a magnified view thereof. As a result, the light-emitting area of ​​each subpixel in the main image data was calculated to be 283 pixels for red, 406 pixels for green, and 582 pixels for blue.

[0532] Next, the change in the luminescence area was calculated using luminescence photographs taken of the display device with an optical microscope. The magnification, resolution, and focus of each image data used in the calculation were kept the same.

[0533] The number of pixels used to calculate the change in the light-emitting area was determined by selecting 500 pixels within a rectangular area of ​​20 pixels vertically and 25 pixels horizontally, as shown in Figure 44. This can be set as appropriate depending on the image data used.

[0534] The luminescent area was calculated by using general-purpose image processing software (ImageJ-win64) to perform black and white binarization on a luminescent photograph like the one in Figure 44, thereby recognizing the luminescent and non-luminescent areas. In this process, it was necessary to set a threshold to specify which pixels should be recognized as luminescent. This threshold was set by comparing the luminescent area (number of pixels in the image) calculated in Figure 43 with the area of ​​the binarized, recognized luminescent portion (number of pixels in the image). Specifically, when binarization was performed using a certain threshold, the number of pixels recognized as luminescent (average per pixel) was close to the number of pixels in the luminescent area calculated in Figure 43.

[0535] After performing this image processing, the change in the light-emitting area of ​​500 pixels calculated from the image data captured for each operating time is shown in Figures 45A and 45B. Figure 45A shows the change in the number of pixels, and Figure 45B shows the rate of change with the average value of the light-emitting area in the initial state set to 100%.

[0536] Thus, it has been found that a display device according to one aspect of the present invention is a display device that has excellent characteristics, such as having an ultra-high resolution of 5009 ppi while exhibiting small changes in the light-emitting area over time.

[0537] (Reference Example 3) This reference example describes the characteristics of light-emitting devices fabricated under three conditions: no exposure to air (Condition 1), conditions including etching of alumina with an aqueous solution containing hydrofluoric acid and nitric acid (including phosphoric acid) (Conditions 2-1, 2-2), and conditions including etching of alumina with an aqueous solution containing phosphoric acid and hydrofluoric acid but not nitric acid (Conditions 3-1, 3-2). Details of each condition will be described later.

[0538] The light-emitting device is a single-structure light-emitting device having a light-emitting layer that exhibits green phosphorescence. The element structure of this light-emitting device is shown in the table below.

[0539]

[0540] In the table, Cz160 and Cz292 are organic compounds containing a carbazole skeleton, Am190 is an organic compound having an arylamine structure, TZn070 and TZn040 are organic compounds containing a triazine skeleton, Ir544 is a phosphorescent material that emits green phosphorescence, and Phen026 is an organic compound containing a phenanthroline skeleton. Furthermore, under each condition, light-emitting devices were fabricated with electron transport layers of four different thicknesses: 10 nm, 17 nm, 24 nm, and 31 nm. These light-emitting devices were fabricated on a 0.7 mm glass substrate.

[0541] Condition 1 is a condition in which, after fabricating the anode, a light-emitting device having the structure described above is fabricated continuously from the hole injection layer to the cap layer using a vacuum deposition apparatus without exposure to the atmosphere.

[0542] Condition 2-1 involves forming an electron transport layer on a light-emitting device having the structure described above using a vacuum deposition apparatus, and then treating it in an aqueous solution containing hydrofluoric acid and nitric acid (including phosphoric acid) for 230 seconds in air at room temperature, resulting in approximately 1 × 10⁻⁶ −４ The substrate is returned to a vacuum deposition apparatus where the internal pressure is reduced to Pa, and after heating at 80°C for 1.5 hours, the cap layer is formed from the electron injection layer.

[0543] Condition 2-2 is a condition in which the photolithography process of the light-emitting device is carried out using an aqueous solution (containing phosphoric acid) containing hydrofluoric acid and nitric acid. Specifically, after forming the electron transport layer of the light-emitting device having the structure described above using a vacuum deposition apparatus, a 30 nm thin layer of aluminum oxide was deposited using the ALD method with trimethylaluminum (TMA) as a precursor and water vapor as an oxidizing agent. Subsequently, a molybdenum (Mo) film was deposited as a mask film to a thickness of 50 nm by sputtering. Then, a resist was formed using a photoresist, and the molybdenum was processed into a predetermined shape using lithography to form a mask layer. Specifically, the mask layer was processed to enclose the pixel electrodes by 0.5 μm or more. Next, using the above mask layer, a sacrificial film and an organic compound layer consisting of an electron transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer were processed into predetermined shapes to form a sacrificial layer and an island-shaped organic compound layer. Subsequently, the mask layer was removed by dry etching. Next, a 15 nm thick aluminum oxide film was deposited on the sacrificial layer as a protective layer using the ALD method, with TMA as the precursor and water vapor as the oxidizing agent. Then, a photosensitive polymer material was applied to the protective layer, and the photosensitive polymer material in the region overlapping with the first electrode was removed using photolithography to form an opening and create an LFP (Local Filling Planarization) structure. After that, the film was treated for 500 seconds in an aqueous solution containing hydrofluoric acid and nitric acid (containing phosphoric acid) in air at room temperature, resulting in approximately 1 × 10⁻⁶ layers. −４ The substrate is returned to a vacuum deposition apparatus where the internal pressure is reduced to Pa, and after heating at 80°C for 1.5 hours, the cap layer is formed from the electron injection layer.

[0544] Condition 3-1 involves forming an electron transport layer on a light-emitting device having the structure described above using a vacuum deposition apparatus, and then treating it in an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid) for 230 seconds in air at room temperature, resulting in approximately 1 × 10⁻⁶ −４ The substrate is returned to a vacuum deposition apparatus where the internal pressure is reduced to Pa, and after heating at 80°C for 1.5 hours, the cap layer is formed from the electron injection layer.

[0545] Condition 3-2 is a condition in which the photolithography process of the light-emitting device is carried out using an aqueous solution (without nitric acid) containing hydrofluoric acid and phosphoric acid. Specifically, after forming the electron transport layer of the light-emitting device having the structure described above using a vacuum deposition apparatus, a 30 nm thin layer of aluminum oxide was deposited using the ALD method with trimethylaluminum (TMA) as a precursor and water vapor as an oxidizing agent. Subsequently, a molybdenum (Mo) film was deposited as a mask film to a thickness of 50 nm by sputtering. Then, a resist was formed using a photoresist, and the molybdenum was processed into a predetermined shape using lithography to form a mask layer. Specifically, the mask layer was processed to enclose the pixel electrodes by 0.5 μm or more. Next, using the above mask layer, a sacrificial film and an organic compound layer consisting of an electron transport layer, a light-emitting layer, a hole transport layer, and a hole injection layer were processed into predetermined shapes to form a sacrificial layer and an island-shaped organic compound layer. Subsequently, the mask layer was removed by dry etching. Next, a 15 nm thick aluminum oxide film was deposited on the sacrificial layer as a protective layer using the ALD method, with TMA as the precursor and water vapor as the oxidizing agent. Then, a photosensitive polymer material was applied to the protective layer, and the photosensitive polymer material in the region overlapping with the first electrode was removed using photolithography to form an opening and create an LFP (Local Filling Planarization) structure. After that, the film was treated for 500 seconds in an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid) in air at room temperature, resulting in approximately 1 × 10⁻⁶ layers. −４ The substrate is returned to a vacuum deposition apparatus where the internal pressure is reduced to Pa, and after heating at 80°C for 1.5 hours, the cap layer is formed from the electron injection layer.

[0546] Figure 34 shows the current density-voltage characteristics of the light-emitting devices fabricated as described above. Furthermore, Relative V (the ratio of the voltage in each light-emitting device fabricated under conditions 2-1 to 3-2 to the voltage in the light-emitting device fabricated under condition 1, where the electron transport layer thickness is the same (10 mA / cm²)) is also shown. ２ Figure 35 shows the results for each electron transport layer thickness. Figure 35A shows the results under conditions where treatment was performed with an aqueous solution containing hydrofluoric acid and nitric acid (including phosphoric acid) (Conditions 2-1, 2-2), and Figure 35B shows the results under conditions where treatment was performed with an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid) (Conditions 3-1, 3-2).

[0547] As shown in Figures 34 and 35, the light-emitting devices fabricated under conditions where treatment was performed with an aqueous solution containing hydrofluoric acid and nitric acid (including phosphoric acid) (Conditions 2-1 and 2-2) tended to show a greater increase in driving voltage as the thickness of the electron transport layer increased. On the other hand, in the light-emitting devices fabricated under conditions where treatment was performed with an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid) (Conditions 3-1 and 3-2), the driving voltage increased under condition 3-2, where aluminum oxide was formed on the electron transport layer, processed the organic layer, and then treated and removed with an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid). However, under condition 3-1, where the surface of the electron transport layer was treated with an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid), there was almost no increase in driving voltage.

[0548] Furthermore, Figure 36 shows the current efficiency-current density characteristics of the above-mentioned light-emitting device. Also, Relative η (the ratio of the current efficiency of each light-emitting device fabricated under conditions 2-1 to 3-2 to the current efficiency of a light-emitting device fabricated under condition 1, where the electron transport layer thickness is the same (10 mA / cm²)) is shown. ２ Figure 37 shows the results for each electron transport layer thickness. Figure 37A shows the results under conditions where treatment was performed with an aqueous solution containing hydrofluoric acid and nitric acid (including phosphoric acid) (Conditions 2-1, 2-2), and Figure 37B shows the results under conditions where treatment was performed with an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid) (Conditions 3-1, 3-2).

[0549] As can be seen from Figures 36 and 37, there was no significant difference in current efficiency between conditions 2-1 and 2-2 and between conditions 3-1 and 3-2.

[0550] Next, Figure 38 shows the normalized brightness-time variation characteristics of the above-mentioned light-emitting devices with electron transport layer thicknesses of 10 nm and 31 nm. Figure 38A shows the results for the device with an electron transport layer thickness of 10 nm, and Figure 38B shows the results for the device with an electron transport layer thickness of 31 nm. Furthermore, Figure 39 shows the results for each condition, summarizing the time (LT95 time) when the brightness reached 95% of the initial brightness. Figure 39 shows the results for the device with an electron transport layer thickness of 10 nm and 31 nm.

[0551] Thus, under the conditions in which the sample was treated with an aqueous solution containing hydrofluoric acid and nitric acid (containing phosphoric acid) (Conditions 2-1 and 2-2), there was a strong tendency for the LT95 time to decrease as the thickness of the electron transport layer increased. However, under the conditions in which the sample was treated with an aqueous solution containing hydrofluoric acid and phosphoric acid (without nitric acid) (Conditions 3-1 and 3-2), this tendency was smaller.

[0552] (Reference Example 4) This reference example shows the results of an investigation into the change in the characteristics of a light-emitting device depending on the type of oxidant used for the sacrificial layer (sacrificial film) formed on the electron transport layer.

[0553] The light-emitting device is a single-structure light-emitting device having a light-emitting layer that exhibits green phosphorescence. The element structure of this light-emitting device is shown in the table below.

[0554]

[0555] In the table, Cz160 is an organic compound containing a carbazole skeleton, DBQ143 is an organic compound containing a dibenzoquinoxaline skeleton, Ir167 is a phosphorescent material that emits green phosphorescence, and Phen028 is an organic compound containing a phenanthroline skeleton. This light-emitting device was fabricated on a 0.7 mm glass substrate.

[0556] The light-emitting device is formed up to the electron transport layer using a vacuum deposition apparatus, and then the electron transport layer is formed using the ALD method with trimethylaluminum (TMA) as a precursor, and water vapor (H ２ O) or ozone (O) ３ Using ) as an oxidizing agent, a 30 nm aluminum oxide film was deposited.

[0557] Subsequently, IGZO was deposited by sputtering to a film thickness of 50 nm. After that, the IGZO and aluminum oxide were removed in air at room temperature, resulting in approximately 1 × 10⁻⁶ −４ The substrate was returned to the vacuum deposition apparatus, where the internal pressure was reduced to Pa, and after heating at 80°C for 1.5 hours, the electron injection layer was formed into a cap layer.

[0558] The current density-voltage characteristics of the light-emitting device fabricated as described above are shown in Figures 40 and 41, and the current efficiency-current density is shown in Figure 42. In the figures, the plot labeled "water vapor" represents the amount of water vapor (H) used as an oxidizing agent when depositing aluminum oxide using the ALD method. ２ In the light-emitting device using O), the plots shown for ozone represent ozone (O) as the oxidizing agent. ３ This is the result of using a light-emitting device.

[0559] As shown in Figures 40 to 42, when aluminum oxide is deposited using the ALD method, water vapor (H) is used as the oxidizing agent. ２ Light-emitting devices using ozone (O) are ３ It was found that, compared to light-emitting devices using ), it exhibits very good characteristics such as a lower driving voltage and higher current efficiency. Therefore, when performing the photolithography process, the sacrificial film to be placed on the EL layer is prepared by the ALD method using water vapor (H) as the oxidizing agent. ２ It was found that it is preferable to use an aluminum oxide film formed using O).

[0560] 100A: Display device, 100B: Display device, 100C: Display device, 100E: Display device, 100D: Display device, 100: Insulator, 101c: First electrode, 101d: First electrode, 101R: First electrode, 101G: First electrode, 101B: First electrode, 101: First electrode, 102: Second electrode, 103B: Organic compound layer, 103Bf: Organic compound film, 103c: Organic compound layer, 103d: Organic compound layer, 103G: Organic compound layer, 103Gf: Organic compound film, 103R: Organic compound layer, 103Rf: Organic compound film, 103: Organic compound layer, 104: First EL layer, 104R: first EL layer, 104G: first EL layer, 104B: first EL layer, 105: second EL layer, 110B: sub-pixel, 110G: sub-pixel, 110R: sub-pixel, 110: sub-pixel, 111c: hole injection layer, 111d: hole injection layer, 111: hole injection layer, 112: hole transport layer, 112c_1: hole transport layer, 112c_2: hole transport layer, 112d_1: hole transport layer, 112d_2: hole transport layer, 112R: conductive layer, 112B: conductive layer, 113: light-emitting layer, 113c_1: light-emitting layer, 113c_2: light-emitting layer, 113d_1: light-emitting layer, 113d_2: light-emitting layer , 114: electron transport layer, 114c_1: electron transport layer, 114c_2: electron transport layer, 114d_1: electron transport layer, 114d_2: electron transport layer, 115: electron injection layer, 116: intermediate layer, 116c: intermediate layer, 116d: intermediate layer, 117: second region, 117c: second region, 117d: second region, 118: third region, 118c: third region, 118d: third region, 119: first region, 119c: first region, 119d: first region, 120: substrate, 122: resin layer, 125f: inorganic insulating film, 125: inorganic insulating layer, 126R: conductive layer, 126B: conductive layer, 127a: insulating layer, 127f: insulating film, 127: insulating layer, 128: layer, 129R: conductive layer, 129B: conductive layer, 130: light-emitting device, 130B: light-emitting device, 130G: light-emitting device, 130R: light-emitting device, 130c: light-emitting device, 130d: light-emitting device, 131: protective layer, 132B: colored layer, 132G: colored layer, 132R: colored layer, 140: connection part, 141: region, 142: adhesive layer, 151B: conductive layer, 151C: conductive layer, 151f: conductive film, 151G: conductive layer, 151R: conductive layer, 151: conductive layer, 152B: conductive layer, 152C: conductive layer,152f: conductive film, 152G: conductive layer, 152R: conductive layer, 152: conductive layer, 153: insulating layer, 156B: insulating layer, 156C: insulating layer, 156f: insulating film, 156G: insulating layer, 156R: insulating layer, 156: insulating layer, 157: light-shielding layer, 158B: sacrificial layer, 158Bf: sacrificial film, 158G: sacrificial layer, 158Gf: sacrificial film, 158R: sacrificial layer, 158Rf: sacrificial film, 159B: mask layer, 159Bf: mask film, 159G: mask layer, 159Gf: mask film, 159R: mask layer, 159Rf: mask film, 166: conductive layer, 171: insulating layer, 172: conductive layer, 17 3: Insulating layer, 174: Insulating layer, 175: Insulating layer, 176: Wiring, 177: Pixel area, 178: Pixel, 179: Conductive layer, 190B: Resist mask, 190G: Resist mask, 190R: Resist mask, 191: Resist mask, 201: Transistor, 204: Connection area, 205: Transistor, 211: Insulating layer, 213: Insulating layer, 214: Insulating layer, 215: Insulating layer, 221: Conductive layer, 222a: Conductive layer, 222b: Conductive layer, 223: Conductive layer, 224B: Conductive layer, 224C: Conductive layer, 224G: Conductive layer, 224R: Conductive layer, 231: Semiconductor layer, 240: Capacitance 241: conductive layer, 242: connecting layer, 243: insulating layer, 245: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 271: plug, 280: display module, 281: display unit, 282: circuit unit, 283a: pixel circuit, 283: pixel circuit unit, 284a: pixel, 284: pixel unit, 285: terminal unit, 286: wiring unit, 290: FPC, 291: substrate, 292: substrate, 301: substrate, 310: transistor, 311: conductive layer, 312: low resistance region, 313: insulating layer, 314: insulating layer, 315: element isolation layer, 351: substrate, 352: substrate ,353: FPC, 354: IC, 355: Wiring, 356: Circuit, 400: Substrate, 403: Area, 404: Area, 501: First light-emitting unit, 501c: First light-emitting unit, 501d: First light-emitting unit, 502: Second light-emitting unit, 502c: Second light-emitting unit, 502d: Second light-emitting unit, 700A: Electronic equipment, 700B: Electronic equipment, 721: Housing, 723: Mounting part, 727: Earphone part, 750: Earphone, 751: Display panel, 753: Optical component, 756: Display area, 757: Frame, 758: Nose pad, 800A: Electronic equipment,800B: Electronic equipment, 820: Display unit, 821: Housing, 822: Communication unit, 823: Mounting unit, 824: Control unit, 825: Imaging unit, 827: Earphone unit, 832: Lens, 6500: Electronic equipment, 6501: Housing, 6502: Display unit, 6503: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective component, 6511: Display panel, 6512: Optical component, 6513: Touch sensor panel, 6515: FPC, 6516: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit, 7100: Television equipment, 7151: Remote control unit, 7171: Housing, 7173: Stand, 7200: Notebook personal computer Ta, 7211: Enclosure, 7212: Keyboard, 7213: Pointing device, 7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 9002: Camera, 9003: Speaker, 9005: Operation key, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9171: Personal digital assistant, 9172: Personal digital assistant, 9173: Tablet terminal, 9200: Personal digital assistant, 9201: Personal digital assistant,

Claims

A method for fabricating a tandem light-emitting device, comprising an EL layer, a first light-emitting layer, an intermediate layer, and a second light-emitting layer, The aforementioned intermediate layer comprises a metal, a first organic compound, and a second organic compound. The first organic compound is an organic compound comprising an electron-donating group and a first π-electron-deficient heteroaromatic ring, The second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring, A method for fabricating a tandem light-emitting device, wherein the EL layer is processed into a predetermined shape using an etching solution containing hydrofluoric acid and phosphoric acid but not nitric acid. A first step of forming a first electrode, A second step of forming an EL layer on the first electrode, A third step of forming a barrier layer on the EL layer, A fourth step of forming a photomask on the barrier layer, A fifth step involves processing the EL layer using the aforementioned photomask, A sixth step involves removing the barrier film and exposing the EL layer, The seventh step is to form a second electrode on the EL layer, The EL layer comprises a first light-emitting layer, an intermediate layer, and a second light-emitting layer. The aforementioned intermediate layer comprises a metal, a first organic compound, and a second organic compound. The first organic compound is an organic compound comprising an electron-donating group and a first π-electron-deficient heteroaromatic ring, The second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring, A method for fabricating a tandem light-emitting device, wherein the sixth step involves using an etching solution containing hydrofluoric acid and phosphoric acid but not nitric acid. A display device having a plurality of pixels, including a first pixel which includes at least adjacent light-emitting devices A and light-emitting device B, The aforementioned light-emitting device A is It comprises a first electrode A, a second electrode A, and an EL layer A located between the first electrode A and the second electrode A. The EL layer A comprises a first light-emitting layer A, an intermediate layer A, and a second light-emitting layer A. The intermediate layer A is located between the first light-emitting layer A and the second light-emitting layer A. The aforementioned light-emitting device B is It comprises a first electrode B, a second electrode B, and an EL layer B located between the first electrode B and the second electrode B. The EL layer B comprises a first light-emitting layer B, an intermediate layer B, and a second light-emitting layer B. The intermediate layer B is located between the first light-emitting layer B and the second light-emitting layer B. The intermediate layer A and the intermediate layer B each contain a metal, a first organic compound, and a second organic compound. The first organic compound is an organic compound comprising an electron-donating group and a first π-electron-deficient heteroaromatic ring, The second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring, The second electrode A and the second electrode B are made of films of the same composition. The first electrode A and the first electrode B, the first light-emitting layer A and the first light-emitting layer B, the intermediate layer A and the intermediate layer B, and the second light-emitting layer A and the second light-emitting layer B are all independent of each other. A display device in which the aforementioned plurality of pixels are arranged at a density of 5000 ppi or more. In claim 3, A display device in which the second electrode A and the second electrode B are formed by a continuous film. In claim 3, A display device wherein the first π-electron-deficient heteroaromatic ring is a heteroaromatic ring containing two or more pyridine rings. In claim 3, The first organic compound is a display device having a phenanthroline skeleton. In claim 3, A display device wherein the first organic compound is an organic compound having an acid dissociation constant pKa of 8 or higher. In claim 3, The second organic compound is a display device having an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), a triazole ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), or a triazine ring. In claim 3, The second organic compound is a display device with an acid dissociation constant pKa less than 4. In any one of claims 3 to 9, A display device wherein the metal is a metal belonging to Group 3, Group 11, Group 12, or Group 13. In any one of claims 3 to 9, The aforementioned electron donor base, A display device comprising one or more alkyl groups, alkoxy groups, aryloxy groups, alkylamino groups, arylamino groups, and aliphatic cyclic amino groups. In any one of claims 3 to 9, A display device wherein the minimum value of the electrostatic potential of the first organic compound is -0.085 or less when the threshold of the electron density distribution is 0.0004.

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