Light emitting device

Abstract

Provided is a light-emitting device having good characteristics. In the light emitting device including a plurality of organic compound layers formed on the same insulating surface, the organic compound layers include a first light emitting layer, a second light emitting layer, and an intermediate layer including a first layer including a metal or a metal compound, a first organic compound, and a second organic compound, the first organic compound includes a p-electron-deficient heteroaromatic ring, and the second organic compound includes two or more heteroaromatic rings bonded or fused to each other and including three or more heteroatoms in total. The second organic compound has a function in which two or more of three or more heteroatoms interact with a metal or a metal compound as a polydentate ligand.

Description

Technical Field

[0001] One embodiment of the present invention relates to a light-emitting device. Note that one embodiment of the present invention is not limited to the above-mentioned technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method or a manufacturing method. In addition, one embodiment of the present invention relates to a process, a machine, a product or a composition of matter. Therefore, specifically, as examples of the technical field of one embodiment of the present invention disclosed in this specification, semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, storage devices, camera devices, electronic devices, driving methods of these devices or manufacturing methods of these devices can be cited. Background Art

[0002] In recent years, display devices have been expected to be used in a variety of applications. For example, large-scale display devices are used in home televisions (also known as televisions or TV receivers), digital signage, and public information displays (PIDs). Furthermore, research and development is underway into touch-panel smartphones and tablet computers as portable information terminals.

[0003] Furthermore, there is a demand for higher-definition display devices. Devices requiring high-definition displays, such as those for virtual reality (VR), augmented reality (AR), substitute reality (SR), and mixed reality (MR), are being actively developed.

[0004] As a display device, for example, light-emitting devices including light-emitting devices (also called light-emitting elements) are being developed. Light-emitting devices utilizing the electroluminescence (EL) phenomenon (also called "EL devices" or "EL elements") have been used in display devices due to their advantages such as ease of thinning and weight reduction, high-speed response to input signals, and ability to be driven using a DC constant voltage power supply.

[0005] Patent Document 1 discloses a display device for VR using an organic EL device (also referred to as an organic EL element).

[0006] [Patent Document 1] International Patent Application Publication No. 2018 / 087625 Summary of the Invention

[0007] As one of the methods for producing organic semiconductor films into a predetermined shape, vacuum evaporation using a metal mask (mask evaporation) is widely used. However, with the recent progress in high density and high resolution, further high resolution through mask evaporation has reached its limit due to various reasons, such as problems with positional alignment accuracy and spacing with the substrate. On the other hand, by shaping the organic semiconductor film using lithography, a denser pattern can be formed. In addition, since this method can easily be applied to large areas, research on the processing of organic semiconductor films using lithography has been conducted.

[0008] Note that when processing an organic semiconductor film using lithography, the driving voltage of the light-emitting device may increase significantly or the current efficiency may decrease significantly due to the influence of oxygen or water in the atmosphere or chemical solutions or water during the process.

[0009] An object of one embodiment of the present invention is to provide a light-emitting device with good characteristics. Another object of one embodiment of the present invention is to provide a light-emitting device with high reliability. Another object of one embodiment of the present invention is to provide a novel light-emitting device.

[0010] Note that the inclusion of these objectives does not preclude the existence of other objectives. Note that one embodiment of the present invention does not necessarily achieve all of the aforementioned objectives. Furthermore, if objectives other than the aforementioned objectives are clearly present in the specification, drawings, and claims, such objectives may be inferred from the description of the specification, drawings, and claims.

[0011] One embodiment of the present invention is a light-emitting device, which includes a first electrode, a second electrode and an organic compound layer, the organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer, the intermediate layer is located between the first light-emitting layer and the second light-emitting layer, the intermediate layer contains a metal or a metal compound, a first organic compound and a second organic compound different from the first organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, the second organic compound includes two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms, and the second organic compound has a function as a multidentate ligand by which two or more of the three or more heteroatoms interact with the metal or metal compound.

[0012] One embodiment of the present invention is a light-emitting device, which includes a first electrode, a second electrode and an organic compound layer, the organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer, the intermediate layer is located between the first light-emitting layer and the second light-emitting layer, the intermediate layer contains a metal or a metal compound, a first organic compound and a second organic compound different from the first organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, the second organic compound includes two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms, the second organic compound has a function as a multidentate ligand by which two or more of the three or more heteroatoms interact with the metal or metal compound, the first organic compound and the metal or metal compound form a donor energy level through interaction, and act as an electron donor to the second organic compound.

[0013] One embodiment of the present invention is a light-emitting device, which includes a first electrode, a second electrode and an organic compound layer, the organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer, the intermediate layer is located between the first light-emitting layer and the second light-emitting layer, the intermediate layer includes a metal or a metal compound, a first organic compound and a second organic compound different from the first organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, the second organic compound includes two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms, and a mass-to-charge ratio equivalent to the sum of the mass number of the first organic compound, the mass number of the second organic compound and the mass number of the metal or metal compound is detected in the intermediate layer using ToF-SIMS measurement.

[0014] One embodiment of the present invention is a light-emitting device, which includes a first electrode, a second electrode and an organic compound layer, the organic compound layer is located between the first electrode and the second electrode, the organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer, the intermediate layer is located between the first light-emitting layer and the second light-emitting layer, the intermediate layer contains a metal or a metal compound, a first organic compound and a second organic compound different from the first organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, the second organic compound is an organic compound represented by the general formula (G1-1), and a mass-to-charge ratio equivalent to the sum of the mass number of the first organic compound, the mass number of the second organic compound and the mass number of the metal or metal compound is detected in the intermediate layer using ToF-SIMS measurement.

[0015] [Chemical Formula 1]

[0016] In the above general formula (G1-1), A 1 、A 2 and A 3Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 、A 2 and A 3 They may also form a condensed ring.

[0017] One embodiment of the present invention is a light-emitting device, which includes a first electrode, a second electrode and an organic compound layer, the organic compound layer is located between the first electrode and the second electrode, the organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer, the intermediate layer is located between the first light-emitting layer and the second light-emitting layer, the intermediate layer contains a metal or a metal compound, a first organic compound and a second organic compound different from the first organic compound, the first organic compound includes a π-electron-deficient heteroaromatic ring, the second organic compound is an organic compound represented by the general formula (G1-2), and a mass-to-charge ratio equivalent to the sum of the mass number of the first organic compound, the mass number of the second organic compound and the mass number of the metal or metal compound is detected in the intermediate layer using ToF-SIMS measurement.

[0018] [Chemical Formula 2]

[0019] In the above general formula (G1-2), A 1 and A 2 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 and A 2 They can also form fused rings with each other, A 1 Contains two or more nitrogen atoms.

[0020] In addition, one embodiment of the present invention is a light-emitting device that is one of a plurality of light-emitting devices formed on the same insulating surface, the light-emitting device including a first electrode, a second electrode, and an organic compound layer, the first electrode being independently provided in each of adjacent light-emitting devices, the second electrode being shared by the adjacent light-emitting devices, the organic compound layer being located between the first electrode and the second electrode, the organic compound layer including a first light-emitting layer, a second light-emitting layer, and an intermediate layer, the intermediate layer being located between the first light-emitting layer and the second light-emitting layer, the first light-emitting layer, the intermediate layer, and the second light-emitting layer being independently provided in each of the adjacent light-emitting devices, and their contours being aligned or substantially aligned, the intermediate layer including a first layer, the first layer including a metal or a metal compound, a first organic compound, and a second organic compound, the first organic compound including a π-electron-deficient heteroaromatic ring, the second organic compound including two or more heteroaromatic rings bonded or fused to each other to include a total of three or more heteroatoms, and the second organic compound having a function as a multidentate ligand in which two or more of the three or more heteroatoms interact with the metal or the metal compound.

[0021] In the light-emitting device having the above structure, the second organic compound has a function of interacting with the metal or the metal compound via two or more of the three or more heteroatoms as a bidentate ligand or a tridentate ligand.

[0022] In the light-emitting device having the above structure, the heteroatom is a nitrogen atom.

[0023] In addition, one embodiment of the present invention is a light-emitting device that is one of a plurality of light-emitting devices formed on the same insulating surface, the light-emitting device including a first electrode, a second electrode, and an organic compound layer, the first electrode being independently arranged in each of adjacent light-emitting devices, the second electrode being commonly used by adjacent light-emitting devices, the organic compound layer being located between the first electrode and the second electrode, the organic compound layer including a first light-emitting layer, a second light-emitting layer, and an intermediate layer, the intermediate layer being located between the first light-emitting layer and the second light-emitting layer, the first light-emitting layer, the intermediate layer, and the second light-emitting layer being independently arranged in each of adjacent light-emitting devices, and their contours being aligned or approximately aligned, the intermediate layer including a first layer, the first layer including a metal or a metal compound, a first organic compound, and a second organic compound, the first organic compound including a π-electron-deficient heteroaromatic ring, and the second organic compound being an organic compound represented by the general formula (G1-1).

[0024] [Chemical Formula 3]

[0025] In the above general formula (G1-1), A 1 、A 2 and A 3 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 、A 2 and A 3 They may also form a condensed ring.

[0026] In the light-emitting device having the above structure, the second organic compound has a function as a tridentate ligand interacting with the metal or the metal compound via the nitrogen atom.

[0027] In addition, one embodiment of the present invention is a light-emitting device that is one of a plurality of light-emitting devices formed on the same insulating surface, the light-emitting device including a first electrode, a second electrode, and an organic compound layer, the first electrode being independently arranged in each of adjacent light-emitting devices, the second electrode being commonly used by adjacent light-emitting devices, the organic compound layer being located between the first electrode and the second electrode, the organic compound layer including a first light-emitting layer, a second light-emitting layer, and an intermediate layer, the intermediate layer being located between the first light-emitting layer and the second light-emitting layer, the first light-emitting layer, the intermediate layer, and the second light-emitting layer being independently arranged in each of adjacent light-emitting devices, and their contours being aligned or approximately aligned, the intermediate layer including a first layer, the first layer including a metal or a metal compound, a first organic compound, and a second organic compound, the first organic compound including a π-electron-deficient heteroaromatic ring, and the second organic compound being an organic compound represented by the general formula (G1-2).

[0028] [Chemical Formula 4]

[0029] In the above general formula (G1-2), A 1 and A 2 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 and A 2 They can also form fused rings with each other, A 1 Contains two or more nitrogen atoms.

[0030] In the light-emitting device having the above structure, the second organic compound has a function as a bidentate ligand interacting with the metal or the metal compound via the nitrogen atom.

[0031] In the above light-emitting device, the heteroaromatic ring is a π-electron-deficient heteroaromatic ring.

[0032] In the above light emitting device, the heteroaromatic ring includes at least one of a pyridine ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), a triazine ring, an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring) and a triazole ring.

[0033] In the above light-emitting device, at least one of the two or more heteroaromatic rings includes a diazine ring (a pyrazine ring, a pyrimidine ring, a pyridazine ring) or a triazine ring.

[0034] In the above light-emitting device, the two or more heteroaromatic rings include three or more pyridine rings in total.

[0035] In the above light-emitting device, the first organic compound has an electron-donating group.

[0036] In the above light-emitting device, the electron-donating group is at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group and a heterocyclic amino group.

[0037] In the above light-emitting device, the first organic compound has an acidity coefficient pKa of 8 or greater.

[0038] In the above light-emitting device, the first organic compound includes a phenanthroline ring.

[0039] In the above-mentioned light-emitting device, the glass transition temperature of the second organic compound is T g Above 100°C.

[0040] In the above light-emitting device, the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound.

[0041] In the above light-emitting device, the metal belongs to Group 1, Group 3, Group 11 or Group 13 in the periodic table.

[0042] In the above light-emitting device, the first layer is a mixture of the metal, the second organic compound and the first organic compound.

[0043] In the above light-emitting device, the first layer is a stacked layer of a layer containing a metal and a layer containing the second organic compound or the first organic compound.

[0044] In the above light-emitting device, a mass-to-charge ratio corresponding to the sum of the mass number of the first organic compound, the mass number of the second organic compound, and the mass number of the metal is detected in the first layer of the intermediate layer by ToF-SIMS measurement.

[0045] Furthermore, one embodiment of the present invention is a light-emitting device including: a light-emitting device having each of the above structures; and a transistor or a substrate.

[0046] Another embodiment of the present invention is an electronic device including: a light-emitting device having the above-described structure; and a detection unit, an input unit, or a communication unit.

[0047] Note that the term "light-emitting device" in this specification includes image display devices using light-emitting devices. Furthermore, a light-emitting device may also include a module in which a light-emitting device on a substrate is attached to a connector such as an anisotropic conductive film or a tape carrier package (TCP); a module in which a printed circuit board is provided at the end of a TCP; or a module in which an integrated circuit (IC) is directly mounted on a light-emitting device using a COG (Chip on Glass) method. Furthermore, a lighting device may also include a light-emitting device.

[0048] According to one embodiment of the present invention, a light-emitting device with excellent characteristics can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with high reliability can be provided. In addition, according to one embodiment of the present invention, a novel light-emitting device can be provided.

[0049] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of the above effects. Effects other than the above effects can be extracted from the description of the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 is a diagram showing a light emitting device; Figure 2 is the analysis result of the spin density distribution in the ground state of the composite material; Figure 3 is the analysis result of the electrostatic potential diagram in the ground state of the composite material; Figure 4 is a schematic diagram illustrating samples used in Examples; 5A to 5D is a diagram showing a light emitting device; Figure 6A and Figure 6B is a top view and a cross-sectional view of the light emitting device; 7A to 7D is a diagram showing a light emitting device; Figures 8A to 8E is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figure 9A and Figure 9B is a cross-sectional view illustrating an example of a method for manufacturing a display device; 10A to 10D is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figures 11A to 11C is a cross-sectional view illustrating an example of a method for manufacturing a display device; 12A to 12C is a cross-sectional view illustrating an example of a method for manufacturing a display device; 13A to 13C is a cross-sectional view illustrating an example of a method for manufacturing a display device; Figure 14A and Figure 14B is a perspective view showing a structural example of a display module; Figure 15A and Figure 15B is a cross-sectional view showing a structural example of a display device; 16A to 16D is a diagram showing an example of an electronic device; 17A to 17F is a diagram showing an example of an electronic device; Figure 18 is a diagram illustrating the sample structure; Figure 19is a graph showing the luminance-current density characteristics of the sample; Figure 20 is a graph showing the luminance-voltage characteristics of the sample; Figure 21 is a graph showing the current efficiency-current density characteristics of the samples; Figure 22 is a graph showing the current density-voltage characteristics of the sample; Figure 23 is a graph showing the electroluminescence spectrum of the sample; Figure 24 is a graph showing the luminance-current density characteristics of the sample; Figure 25 is a graph showing the luminance-voltage characteristics of the sample; Figure 26 is a graph showing the current efficiency-current density characteristics of the samples; Figure 27 is a graph showing the current density-voltage characteristics of the sample; Figure 28 is a graph showing the electroluminescence spectrum of the sample; Figure 29 is a graph showing ESR measurement results of samples; Figure 30 is a graph showing ESR measurement results of samples; Figure 31 is a graph showing reliability measurement results of samples; Figure 32 is a graph showing the luminance-current density characteristics of the sample; Figure 33 is a graph showing the luminance-voltage characteristics of the sample; Figure 34 is a graph showing the current efficiency-current density characteristics of the samples; Figure 35 is a graph showing the current density-voltage characteristics of the sample; Figure 36 is a graph showing the electroluminescence spectrum of the sample; Figure 37A and Figure 37B is a diagram illustrating the structure of a measuring device; Figure 38A Graphs showing the current density-voltage characteristics of device 4A ( H1 ) and device 4A ( H2 ) are shown. Figure 38B Graphs showing the current density-voltage characteristics of device 4B (H1) and device 4B (H2) are shown. Figure 38C 4C(H1) and 4C(H2) are graphs showing current density-voltage characteristics. Figure 39AGraphs showing the current density-voltage characteristics of device 4A (E1) and device 4A (E2) are shown. Figure 39B Graphs showing the current density-voltage characteristics of device 4B (E1) and device 4B (E2) are shown. Figure 39C Graphs showing current density-voltage characteristics of device 4C (E1) and device 4C (E2); Figure 40 is a graph showing current density-voltage characteristics of the light emitting device 5A and the light emitting device 5B; Figure 41 is a graph showing current density-voltage characteristics of the light emitting device 5A and the light emitting device 5B; Figure 42 5A and 5B are graphs showing current efficiency-current density characteristics of the light-emitting device 5A and the light-emitting device 5B; Figure 43 5A and 5B are graphs showing external quantum efficiency-current density characteristics of the light-emitting device 5A and the light-emitting device 5B; Figure 44 1 is a diagram showing electroluminescence spectra of the light-emitting device 5A and the light-emitting device 5B; Figure 45 The current density of the light emitting device 5A is 46.4 mA / cm 2 A graph showing the normalized brightness-time variation characteristics when ; Figure 46A and Figure 46B is a diagram illustrating TOF-SIMS measurement results measured in Examples; Figure 47A and Figure 47B is a diagram illustrating TOF-SIMS measurement results measured in Examples; Figure 48 is a diagram illustrating TOF-SIMS measurement results; Figure 49 is a diagram illustrating TOF-SIMS measurement results; Figure 50 is a diagram illustrating TOF-SIMS measurement results; Figure 51 is a graph illustrating the absorption spectrum of the sample; Figure 52 is a diagram illustrating the sample structure; Figure 53 is a graph showing the luminance-current density characteristics of the sample; Figure 54 is a graph showing the luminance-voltage characteristics of the sample; Figure 55 is a graph showing the current efficiency-current density characteristics of the samples; Figure 56 is a graph showing the current density-voltage characteristics of the sample; Figure 57 is a graph showing external quantum efficiency-current density characteristics of the samples; Figure 58 is a graph showing the electroluminescence spectrum of the sample; Figure 59 is a graph showing capacitance-voltage characteristics of a sample; Figure 60 is a graph showing the luminance-current density characteristics of the sample; Figure 61 is a graph showing the luminance-voltage characteristics of the sample; Figure 62 is a graph showing the current efficiency-current density characteristics of the samples; Figure 63 is a graph showing the current density-voltage characteristics of the sample; Figure 64 is a graph showing the electroluminescence spectrum of the sample; Figure 65 is a graph showing the luminance-current density characteristics of the sample; Figure 66 is a graph showing the luminance-voltage characteristics of the sample; Figure 67 is a graph showing the current efficiency-current density characteristics of the samples; Figure 68 is a graph showing the current density-voltage characteristics of the sample; Figure 69 is a graph showing the electroluminescence spectrum of the sample; Figure 70 is a graph showing the luminance-current density characteristics of the sample; Figure 71 is a graph showing the luminance-voltage characteristics of the sample; Figure 72 is a graph showing the current efficiency-current density characteristics of the samples; Figure 73 is a graph showing the current density-voltage characteristics of the sample; Figure 74 is a graph showing the electroluminescence spectrum of the sample; Figure 75 is a graph showing the blue index-current density characteristics of the sample; Figure 76 is a graph showing reliability measurement results of samples; Figure 77 is a graph showing reliability measurement results of samples; Figure 78 is a graph showing reliability measurement results of samples; Figure 79 is a schematic diagram of a stacked structure of a display device; Figure 80 is a light-emitting photograph of the display device; Figure 81A and Figure 81B is an optical microscope photograph showing pixels of a display device; Figure 82 is a diagram showing the CIE1931 chromaticity coordinates of a display device; Figure 83 is the measurement result of the electroluminescence spectrum of the display device; Figure 84 is a graph showing the luminance-current density characteristics of the sample; Figure 85 is a graph showing the luminance-voltage characteristics of the sample; Figure 86 is a graph showing the current efficiency-current density characteristics of the samples; Figure 87 is a graph showing the current density-voltage characteristics of the sample; Figure 88 is a graph showing the electroluminescence spectrum of the sample; Figure 89 is a graph showing the blue index-current density characteristics of the sample; Figure 90 is a graph showing the luminance-current density characteristics of the sample; Figure 91 is a graph showing the luminance-voltage characteristics of the sample; Figure 92 is a graph showing the current efficiency-current density characteristics of the samples; Figure 93 is a graph showing the current density-voltage characteristics of the sample; Figure 94 is a graph showing the electroluminescence spectrum of the sample; Figure 95 is a graph showing the luminance-current density characteristics of the sample; Figure 96 is a graph showing the luminance-voltage characteristics of the sample; Figure 97 is a graph showing the current efficiency-current density characteristics of the samples; Figure 98 is a graph showing the current density-voltage characteristics of the sample; Figure 99 is a graph showing the electroluminescence spectrum of the sample; Figure 100 is a graph showing the luminance-current density characteristics of the sample; Figure 101 is a graph showing the luminance-voltage characteristics of the sample; Figure 102is a graph showing the current efficiency-current density characteristics of the samples; Figure 103 is a graph showing the current density-voltage characteristics of the sample; Figure 104 is a graph showing the electroluminescence spectrum of the sample; Figure 105 is a graph showing the luminance-current density characteristics of the sample; Figure 106 is a graph showing the luminance-voltage characteristics of the sample; Figure 107 is a graph showing the current efficiency-current density characteristics of the samples; Figure 108 is a graph showing the current density-voltage characteristics of the sample; Figure 109 is a graph showing the electroluminescence spectrum of the sample; Figure 110 is a graph showing the reliability test results of samples. DETAILED DESCRIPTION

[0051] The embodiments are described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description. A person skilled in the art will readily appreciate that the embodiments and details can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the embodiments described below.

[0052] Note that in the structures of the invention described below, the same reference numerals are used in common across different drawings to represent the same parts or parts having the same function, and their repeated descriptions are omitted. In addition, when parts having the same function are represented, the same hatching is sometimes used without the addition of a particular reference numeral.

[0053] In addition, for ease of understanding, the positions, sizes, and ranges of various components shown in the drawings may not necessarily represent their actual positions, sizes, and ranges. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0054] In addition, depending on the situation or state, the terms "film" and "layer" can be interchanged. For example, "conductive layer" can be replaced with "conductive film." Also, for example, "insulating film" can be replaced with "insulating layer."

[0055] Note that in this specification and other documents, devices manufactured using a metal mask or FMM (Fine Metal Mask) are sometimes referred to as devices with an MM (Metal Mask) structure. Furthermore, in this specification and other documents, devices manufactured without using a metal mask or FMM are sometimes referred to as devices with an MML (Metal Mask Less) structure.

[0056] In this specification, holes or electrons are sometimes referred to as "carriers." Specifically, a hole injection layer or electron injection layer is sometimes referred to as a "carrier injection layer," a hole transport layer or electron transport layer is sometimes referred to as a "carrier transport layer," and a hole blocking layer or electron blocking layer is sometimes referred to as a "carrier blocking layer." Note that depending on the cross-sectional shape or characteristics, it may not be possible to clearly distinguish between the carrier injection layer, carrier transport layer, and carrier blocking layer. In addition, a single layer may sometimes have the functions of two or all of the three.

[0057] In this specification, etc., a light-emitting device (also referred to as a light-emitting element) includes an EL layer between a pair of electrodes. The EL layer includes at least a light-emitting layer. In this specification, etc., a light-receiving device (also referred to as a light-receiving element) includes at least an active layer serving as a photoelectric conversion layer between a pair of electrodes. In this specification, etc., one of a pair of electrodes is sometimes referred to as a pixel electrode and the other as a common electrode.

[0058] In this specification, etc., a tapered shape refers to a shape in which at least a portion of a component's side surface is inclined relative to the substrate surface. For example, a region where the angle between the inclined side surface and the substrate surface (also referred to as a taper angle) is less than 90° is preferably present. Note that the component's side surface and substrate surface do not necessarily need to be completely flat; they may be approximately planar with slight curvature or have fine irregularities.

[0059] Note that the term "light-emitting device" in this specification includes image display devices using organic EL devices. Furthermore, a light-emitting device may also include a module in which an organic EL device is attached to a connector such as an anisotropic conductive film or a tape carrier package (TCP); a module in which a printed circuit board is provided at the end of a TCP; or a module in which an integrated circuit (IC) is directly mounted on an organic EL device using a COG (Chip on Glass) method. Furthermore, a lighting device and the like may also include a light-emitting device.

[0060] Implementation Method 1 In this embodiment, referring to Figure 1 A light-emitting device according to one embodiment of the present invention will be described.

[0061] To explain a light-emitting device according to one embodiment of the present invention, Figure 1 The schematic diagram shows two adjacent light-emitting devices, namely, light-emitting device 130a and light-emitting device 130b, formed on the same insulating surface. Both light-emitting devices 130a and 130b are light-emitting devices formed by processing a portion of an organic compound layer using lithography technology.

[0062] The light-emitting device 130a is located on the insulating layer 175 and includes a first electrode 101a having an anode, a second electrode 102 having a cathode, and an organic compound layer 103a. The organic compound layer 103a is located between the first electrode 101a and the second electrode 102. Furthermore, the organic compound layer 103a has a stacked structure of a first light-emitting unit 501a and a second light-emitting unit 502a with an intermediate layer 160a sandwiched therebetween. The first light-emitting unit 501a includes a first light-emitting layer 113a_1. The intermediate layer 160a includes a first layer 161a and a second layer 162a. The second light-emitting unit 502a includes a second light-emitting layer 113a_2 and an electron injection layer 115. In other words, in the above structure, the intermediate layer 160a is located between the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2.

[0063] The light-emitting device 130b is located on the insulating layer 175 and includes a first electrode 101b having an anode, a second electrode 102 having a cathode, and an organic compound layer 103b. The organic compound layer 103b is located between the first electrode 101b and the second electrode 102. Furthermore, the organic compound layer 103b has a stacked structure of a first light-emitting unit 501b and a second light-emitting unit 502b with an intermediate layer 160b sandwiched therebetween. The first light-emitting unit 501b includes a first light-emitting layer 113b_1. The intermediate layer 160b includes a first layer 161b and a second layer 162b. The second light-emitting unit 502b includes a second light-emitting layer 113b_2 and an electron injection layer 115. Alternatively, the intermediate layer 160b can be said to be located between the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2.

[0064] In the light-emitting device 130a or the light-emitting device 130b, each layer other than the electron injection layer 115 in the organic compound layer 103a or the organic compound layer 103b is processed using a lithography technique. Therefore, each layer other than the electron injection layer 115 in the organic compound layer 103a is separated from the layer in the organic compound layer 103b.

[0065] Furthermore, the ends (outlines) of each layer other than the electron-injection layer 115 in the organic compound layer 103a or the organic compound layer 103b are aligned or approximately aligned in a direction perpendicular to the substrate. That is, the first light-emitting layer 113a_1, the intermediate layer 160a (the first layer 161a and the second layer 162a), and the second light-emitting layer 113a_2 are separated from the first light-emitting layer 113b_1, the intermediate layer 160b (the first layer 161b and the second layer 162b), and the second light-emitting layer 113b_2. Furthermore, the ends (outlines) of the first light-emitting layer 113a_1, the intermediate layer 160a (the first layer 161a and the second layer 162a), and the second light-emitting layer 113a_2 are aligned or approximately aligned in a direction perpendicular to the substrate. The first light-emitting layer 113b_1, the intermediate layer 160b (the first layer 161b and the second layer 162b), and the second light-emitting layer 113b_2 are separated from the first light-emitting layer 113a_1, the intermediate layer 160a (the first layer 161a and the second layer 162a), and the second light-emitting layer 113a_2. Furthermore, the ends (outlines) of the first light-emitting layer 113b_1, the intermediate layer 160b (the first layer 161b and the second layer 162b), and the second light-emitting layer 113b_2 are aligned or substantially aligned in a direction perpendicular to the substrate.

[0066] The electron injection layer 115 and the second electrode 102 are preferably formed after processing the layers other than the electron injection layer 115 in the organic compound layer 103a and the layers other than the electron injection layer 115 in the organic compound layer 103b using lithography. In other words, the electron injection layer 115 and the second electrode 102 are preferably continuous layers shared by both the light-emitting devices 130a and 130b.

[0067] The use of a donor substance (also called an electron donor) in the electron injection layer 115 is preferred because it can reduce the voltage of the light-emitting device. Specific examples of the donor substance typically include alkali metals such as lithium (Li) with a small work function or compounds of the alkali metals.

[0068] When the interface of an organic compound layer with an electron injection layer containing such a donor substance is processed using lithography, the influence of oxygen or water in the atmosphere, or chemical solutions or water during the process, may cause a significant increase in the driving voltage of the light-emitting device or a significant decrease in the current efficiency. However, in one embodiment of the present invention, the electron injection layer 115 is formed after processing all layers other than the electron injection layer 115 using lithography. This prevents degradation of the characteristics of the light-emitting device even when a donor substance is used as the electron injection layer 115.

[0069] Furthermore, when processing the organic compound layer using lithography, the distance d between each layer other than the electron injection layer 115 of the organic compound layer 103a and each layer other than the electron injection layer 115 of the organic compound layer 103b can be reduced to less than 10 μm, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, 1.5 μm or less, 1 μm or less, or 0.5 μm or less, compared to the case of masked evaporation. Furthermore, by using, for example, an LSI exposure apparatus, the distance d can be reduced to, for example, less than 500 nm, less than 200 nm, less than 100 nm, or even less than 50 nm during processing on a silicon wafer.

[0070] In addition, it is preferable that an insulating layer be provided in the gap between each layer other than the electron injection layer 115 of the organic compound layer 103 a and each layer other than the electron injection layer 115 of the organic compound layer 103 b, so as to separate each layer other than the electron injection layer 115 of the organic compound layer 103 a from each layer other than the electron injection layer 115 of the organic compound layer 103 b. In this case, there is a region in which the insulating layer is in contact with the electron injection layer 115 or the second electrode 102.

[0071] Preferably, in the light-emitting device 130a, the first light-emitting unit 501a further includes a hole injection layer 111a, a first hole transport layer 112a_1, and a first electron transport layer 114a_1 in addition to the first light-emitting layer 113a_1. Furthermore, the second light-emitting unit 502a further includes a second hole transport layer 112a_2 and a second electron transport layer 114a_2 in addition to the second light-emitting layer 113a_2 and the electron injection layer 115. Furthermore, the intermediate layer 160a may include a third layer 163a between the first layer 161a and the second layer 162a. Note that, as in the second light-emitting unit 502a, when the anode-side surface of the light-emitting unit is in contact with the intermediate layer 160a, the cathode-side second layer 162a of the intermediate layer 160a may also serve as the hole injection layer for the second light-emitting unit 502a. Therefore, a hole injection layer may be provided in the light-emitting unit.

[0072] Preferably, in the light-emitting device 130b, the first light-emitting unit 501b further includes a hole injection layer 111b, a first hole transport layer 112b_1, and a first electron transport layer 114b_1 in addition to the first light-emitting layer 113b_1. Furthermore, the second light-emitting unit 502b further includes a second hole transport layer 112b_2 and a second electron transport layer 114b_2 in addition to the second light-emitting layer 113b_2 and the electron injection layer 115. Furthermore, the intermediate layer 160b may include a third layer 163b between the first layer 161b and the second layer 162b. Note that, as in the second light-emitting unit 502b, when the anode-side surface of the light-emitting unit is in contact with the intermediate layer 160b, the cathode-side second layer 162b of the intermediate layer 160b may also serve as the hole injection layer for the second light-emitting unit 502b. Therefore, a hole injection layer may be provided in this light-emitting unit.

[0073] In addition, if Figure 1 As shown, the top layer of each layer other than the electron injection layer 115 of the organic compound layer 103a is preferably the second electron transport layer 114a_2. Similarly, the top layer of each layer other than the electron injection layer 115 of the organic compound layer 103b is preferably the second electron transport layer 114b_2. By using lithography technology to process the interface on the second electron transport layer 114a_2 and the second electron transport layer 114b_2, it is less likely to be affected by oxygen or water in the atmosphere, or by the chemical solution or water in the process, compared to the case where the interface on the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2 is processed. Therefore, by using an electron transport layer as the top layer of each layer other than the electron injection layer 115 of each organic compound layer, it is further easier to avoid the degradation of the characteristics of the light-emitting device caused by the manufacturing process using lithography technology, but it is preferably processed using lithography technology at least on the upper layer of the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2.

[0074] Note that although Figure 1 In the embodiment, each organic compound layer includes two light-emitting units, but one embodiment of the present invention is not limited thereto. Each organic compound layer may also include three or more light-emitting units. By stacking a plurality of light-emitting units with an intermediate layer between a pair of electrodes, a light-emitting device can be realized that can emit light with high brightness while maintaining a low current density and has high reliability. In addition, a light-emitting device with low power consumption can also be realized. In addition, although Figure 1 Although not shown in the figure, each light-emitting unit may further include a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, an electron injection layer, etc. In addition, each layer may be a stack of two or more layers.

[0075] Note that in this specification, the structure of one of the light-emitting device 130a and the light-emitting device 130b is sometimes shown, but the other one of the light-emitting device 130a and the light-emitting device 130b may have the same structure.

[0076] The intermediate layer 160a sandwiched between the first light-emitting unit 501a and the second light-emitting unit 502a can inject electrons into one light-emitting unit and inject holes into the other light-emitting unit when a voltage is applied between the first electrode 101a and the second electrode 102. Figure 1 In the embodiment, when a voltage is applied so that the potential of the second electrode 102 is higher than that of the first electrode 101a, the intermediate layer 160a injects electrons into the first light-emitting unit 501a and injects holes into the second light-emitting unit 502a.

[0077] exist Figure 1 In the light-emitting device 130a shown, by applying a voltage between a pair of electrodes (the first electrode 101a and the second electrode 102), electrons are injected from the cathode into the electron injection layer 115, and holes are injected from the anode into the hole injection layer 111a, thereby causing current to flow. In addition, electrons are injected from the first layer 161a on the anode side of the intermediate layer 160a into the first electron transport layer 114a_1 in the first light-emitting unit 501a, and holes are injected from the second layer 162a on the cathode side of the intermediate layer 160a into the second hole transport layer 112a_2 in the second light-emitting unit 502a. Furthermore, the injected carriers (electrons and holes) recombine to form excitons. When the carriers (electrons and holes) in the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 containing the light-emitting material recombine to form excitons, the light-emitting material contained in the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 is in an excited state, and light can be emitted from the light-emitting material.

[0078] In addition, if Figure 1 As shown, the first layer 161a on the anode side of the intermediate layer 160a is preferably adjacent to the first electron transport layer 114a_1 and disposed between the first electron transport layer 114a_1 and the second light-emitting unit 502a. By adopting this structure, electrons can be efficiently injected into the first light-emitting unit 501a.

[0079] Here, in order to reduce the driving voltage of the light-emitting device and achieve efficient light emission, it is preferable to reduce the electron injection barrier from the intermediate layer 160a to the first electron transport layer 114a_1 and smoothly inject and transport the electrons generated in the intermediate layer 160a to the first electron transport layer 114a_1. To this end, an alkali metal or alkaline earth metal or a compound thereof with a small work function is generally used as the intermediate layer 160a. However, such metals and compounds are easily degraded by oxygen or water in the atmosphere, as well as water or chemical solutions used in the lithography process, thereby causing a significant increase in the driving voltage of the light-emitting device or a significant decrease in the current efficiency.

[0080] Therefore, it is preferred to use a material that is resistant to oxygen and water in the atmosphere and water and chemical solutions used in the process of lithography technology for the intermediate layer. For this purpose, it is preferred to use a metal that is stable to oxygen and water in the atmosphere and resistant to water and chemical solutions for the intermediate layer 160a. However, this metal is stable and has low electron injection properties. Therefore, sometimes an electron injection barrier is formed between the intermediate layer 160a and the first electron transport layer 114a_1, resulting in an increase in the driving voltage of the light-emitting device and a decrease in the luminous efficiency.

[0081] Therefore, in one embodiment of the present invention, the first layer 161 (first layer 161a and first layer 161b) located on the anode side of the intermediate layer 160a comprises: a metal or metal compound; a first organic compound comprising a π-electron-deficient heteroaromatic ring; and a second organic compound comprising two or more heteroaromatic rings bonded or fused to form a total of three or more heteroatoms. This structure allows the first organic compound to function as an electron donor for the second organic compound in the first layer 161, and the interaction between the first organic compound, the metal or metal compound, and the second organic compound forms a donor energy level (a singly occupied molecular orbital (SOMO) energy level or a highest occupied molecular orbital (HOMO) energy level). When the first organic compound, the metal or metal compound, and the second organic compound interact with each other, the donor energy level (SOMO energy level or HOMO energy level) is a high energy level, thereby reducing the electron injection barrier from the intermediate layer 160a to the first electron transport layer 114a_1, and through this interaction, the electrons generated in the intermediate layer 160a are smoothly injected and transported to the first electron transport layer 114a_1, thereby manufacturing a light-emitting device with a low driving voltage.

[0082] Note that the lowest unoccupied molecular orbital (LUMO) and HOMO energy levels of organic compounds are generally estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, and the like. When comparing values ​​for different compounds, it is preferable to use values ​​estimated from the same measurement.

[0083] Furthermore, the SOMO level originates from the orbital of unpaired electrons contained in metals. When a metal or metal compound interacts with a first organic compound and a second organic compound, the SOMO level can also be distributed in the orbitals of the first and second organic compounds. In other words, the electron orbitals of the metal or metal compound interact with those of the organic compound.

[0084] Note that organic compounds containing multiple atoms capable of interacting with each other can interact more stably with metals or metal compounds. Therefore, as the second organic compound used in one embodiment of the present invention, it is preferred to use a material that interacts with a metal or metal compound as a bidentate or tridentate or higher multidentate ligand. Since the organic compound that interacts with a metal or metal compound as a multidentate ligand becomes stable when interacting with the metal or metal compound, an intermediate layer resistant to oxygen and water in the atmosphere, as well as water and chemical solutions used in the process of lithography, can be formed.

[0085] As the atoms that interact, heteroatoms with non-shared electron pairs in organic compounds can be cited. For example, oxygen (O), nitrogen (N), sulfur (S), phosphorus (P) can be cited, wherein nitrogen is preferably. Nitrogen has a high electronegativity and is therefore easy to interact with metals or metal compounds. In addition, since nitrogen can form conjugated bonds in organic compounds, by using nitrogen in molecules, especially in heteroaromatic rings, organic compounds with high carrier transport properties can be achieved. Note that the heteroaromatic ring is more preferably an even-numbered ring such as a six-membered ring or an eight-membered ring. By adopting this structure, the non-shared electron pair on nitrogen does not involve conjugation and is therefore easy to interact with metals or metal compounds.

[0086] The metal or metal compound, the first organic compound and the second organic compound form a donor energy level (SOMO energy level or HOMO energy level) by interacting with each other, which can reduce the electron injection barrier to the electron transport layer, and the electrons generated in the intermediate layer can be smoothly injected and transported to the electron transport layer. The heteroaromatic ring included in the second organic compound is preferably a π-electron-deficient heteroaromatic ring. By adopting this structure, the second organic compound can have electron transport properties, and can smoothly inject and transport electrons from the intermediate layer to the electron transport layer. In addition, the second organic compound includes two or more heteroaromatic rings, which are bonded or fused to each other and include a total of three or more nitrogen atoms, thereby making it easy to make the LUMO energy level of the second organic compound lower than the LUMO energy level of the first organic compound. By using a material with a LUMO energy level lower than the LUMO energy level of the first organic compound as the second organic compound, the stabilization of the intermediate layer can be achieved when the metal or metal compound, the first organic compound and the second organic compound interact, and an intermediate layer that is not easily degraded by a photolithography process accompanied by atmospheric exposure can be formed. Therefore, even after a photolithography process accompanied by atmospheric exposure of the EL layer, the electrons generated in the intermediate layer can be smoothly injected and transported to the adjacent electron transport layer, thereby suppressing the increase in the driving voltage. A tandem light-emitting device with high luminous efficiency and high reliability can be manufactured using the photolithography process.

[0087] The second organic compound preferably includes a π-electron-deficient heteroaromatic ring having an unshared electron pair. By adopting this structure, it is possible to stably interact with the metal or metal compound. The second organic compound is preferably a material comprising two or more π-electron-deficient heteroaromatic rings having an unshared electron pair and interacting with the metal or metal compound as a bidentate or higher multidentate ligand. Since the organic compound that interacts with the metal or metal compound as a bidentate or higher multidentate ligand becomes stable when interacting with the metal or metal compound, an intermediate layer resistant to oxygen and water in the atmosphere and water and chemical solutions used in the process in lithography can be formed.

[0088] In addition, the first organic compound preferably has an electron donating substituent. By adopting this structure, the first organic compound can have a high HOMO energy level and a high LUMO energy level, so the difference between the LUMO energy level of the first organic compound and the LUMO energy level of the second organic compound can be increased. Therefore, when the metal or metal compound, the first organic compound and the second organic compound interact with each other, further stabilization of the intermediate layer can be achieved, and an intermediate layer that is not easily degraded even after a photolithography process accompanied by atmospheric exposure can be formed. Therefore, even after a photolithography process accompanied by atmospheric exposure of the EL layer, the electrons generated in the intermediate layer can be smoothly injected and transferred to the adjacent electron transport layer, thereby suppressing the rise in the driving voltage, and a tandem light-emitting device with high luminous efficiency and high reliability can be manufactured using a photolithography process.

[0089] In addition, metals with small work functions, such as alkali metals and alkaline earth metals, and their compounds are highly reactive with oxygen or water. Therefore, when used in light-emitting devices processed using lithography, they lead to a decrease in luminous efficiency, an increase in driving voltage, a decrease in driving life, and the generation of shrinkage (non-luminous regions at the ends of the light-emitting portion), which sometimes leads to a decrease in the characteristics of the light-emitting device or a decrease in reliability. However, in one embodiment of the present invention, even when alkali metals or alkaline earth metals or their compounds are used, they interact with a first organic compound including a π-electron-deficient heteroaromatic ring and a second organic compound including two or more heteroaromatic rings that are bonded or fused to each other to form a total of three or more heteroatoms to achieve stabilization. Therefore, an intermediate layer resistant to oxygen and water in the atmosphere, as well as water and chemical solutions used in the lithography process, can be formed.

[0090] In other words, when an alkali metal or alkaline earth metal or a compound thereof is used as the metal or metal compound of one embodiment of the present invention, the donor energy level (SOMO level or HOMO level) formed by the interaction between the metal or metal compound and the first organic compound including the π-electron-deficient heteroaromatic ring can be high energy, making it easy to donate electrons to the second organic compound. Therefore, it is preferable to reduce the electron injection barrier from the intermediate layer 160a to the first electron transport layer 114a_1, and electrons generated in the intermediate layer 160a can be smoothly injected and transported to the first electron transport layer 114a_1.

[0091] Furthermore, transition metals (metal elements belonging to Groups 3 to 11) and typical metals belonging to Groups 12 to 14 have low reactivity with oxygen and water in the atmosphere, as well as water and chemicals used in the lithography process. Therefore, when these metals are used in light-emitting devices, they are less susceptible to degradation by water and oxygen, which can occur when using metals with low work functions. On the other hand, these metals are stable and have low electron injection properties, which can cause a decrease in the luminous efficiency of light-emitting devices, an increase in driving voltage, and a reduction in driving life.

[0092] In one embodiment of the present invention, even if a transition metal (a metal element belonging to Group 3 to Group 11), a metal element belonging to Group 12 to Group 14 in a typical metal, and a metal compound are used, they interact with a first organic compound including a π-electron-deficient heteroaromatic ring to form a donor energy level (SOMO energy level or HOMO energy level), thereby easily supplying electrons to a second organic compound, the second organic compound including two or more heteroaromatic rings, the two or more heteroaromatic rings being bonded or fused to each other and including a total of three or more heteroatoms. Therefore, the electron injection barrier from the intermediate layer 160a to the first electron transport layer 114a_1 can be reduced, and the electrons generated in the intermediate layer 160a can be smoothly injected and transported to the first electron transport layer 114a_1. In addition, an intermediate layer resistant to oxygen and water in the atmosphere and water and liquid used for processes in lithography can be formed, so it is preferred. Therefore, one embodiment of the present invention can provide a light-emitting device with good moisture resistance, good water resistance, good oxygen resistance, good chemical resistance, low driving voltage and good luminous efficiency.

[0093] <Analysis of the Interaction between Metals or Metal Compounds and Organic Compounds Using Quantum Chemical Calculations> Here, the interaction between a metal or a metal compound, a first organic compound having an electron-donating property and an unshared electron pair, and a second organic compound having an electron-transporting property is analyzed using quantum chemical calculations.

[0094] [Estimation of the interaction between metals or metal compounds and organic compounds] Quantum chemical calculations were used to analyze the spin density and electrostatic potential (ESP) when a metal or metal compound interacts with a first organic compound containing a π-electron-deficient heteroaromatic ring and a second organic compound containing two or more heteroaromatic rings bonded or fused to form a total of three or more heteroatoms. Note that the calculations used 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) as the first organic compound, 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as 6,6'(P-Bqn)2BPy) as the second organic compound, and lithium (Li) as the metal.

[0095] Gaussian09 is used as a quantum chemical calculation program. SGI8600 manufactured by HPE is used for calculation. Density functional theory (DFT) is used to calculate the most stable structures of the first organic compound monomer and the second organic compound monomer in the ground state, and the most stable structures of the composite material of the first organic compound, the second organic compound and the metal or the metal compound in the ground state. 6-311G (d, p) is used as the basis function, and B3LYP is used as the functional. The total energy of DFT is expressed as the sum of potential energy, electrostatic energy between electrons, kinetic energy of electrons, and exchange correlation energy including all complex interactions between electrons. In DFT, since the exchange correlation interaction is approximated by the functional (meaning a function of a function) of the single electron potential expressed by the electron density, the calculation accuracy is high.

[0096] Figure 2 The results of the analysis of the spin density distribution in the ground state of a composite material composed of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) are shown. The balls in the figure represent the atoms that make up the compound, and the clouds around the atoms indicate that the threshold value of the electron density distribution in atomic units is 0.0004e / a. 3 (e represents elementary charge (1e=1.60218×10 -19 C), a0 represents the Bohr radius (1a0=5.29177×10 - 11 Note that since the ground states of the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy) are singlet ground states, no spin density distribution is observed.

[0097] In one embodiment of the present invention, when a composite material of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) is in a doublet ground state, the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li) interact with each other, and the metal (Li) coordinates to the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having non-shared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atoms at positions 1 and 10 having non-shared electron pairs in the pyridine ring and the benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy), thereby stabilizing the composite material. Thus, according to Figure 2 It can be seen that the spins originating from the unpaired electrons contained in the metal (Li) are locally distributed on the second organic compound (6,6'(P-Bqn)2BPy). Furthermore, no spin density distribution of the metal (Li) is observed. This indicates that the second organic compound (6,6'(P-Bqn)2BPy) is in a radical anion state due to the interaction between the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li).

[0098] then, Figure 3 The results of analyzing the electrostatic potential map in the ground state of a composite material composed of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) are shown. The balls in the figure represent the atoms that make up the compound, and the clouds around the atoms indicate that the threshold value of the electron density distribution in the atomic unit system is 0.0004e / a. 3 Electrostatic potential in the electron density distribution when . Electrostatic potential is the interaction energy between a positive point charge with unit charge and the electron distribution of a molecule. The electrostatic potential map refers to the electrostatic potential in the equal electron density surface represented by color, where red and blue represent areas with negative and positive electrostatic potential, respectively. Atoms in areas with negative electrostatic potential have negative charges, and atoms in areas with positive electrostatic potential have positive charges. Note that due to Figure 3 Since it is a grayscale image, in order to indicate the region where the electrostatic potential is negative and the region where the electrostatic potential is positive, the region where the electrostatic potential is negative is surrounded by a dotted line, and the region where the electrostatic potential is positive is surrounded by a dashed line.

[0099] In one embodiment of the present invention, when a composite material of a first organic compound (Pyrrd-Phen), a second organic compound (6,6'(P-Bqn)2BPy), and a metal (Li) is in a doublet ground state, the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li) interact with each other, and the metal (Li) coordinates to the nitrogen atoms having non-shared electron pairs (nitrogen atoms (N) at positions 1 and 10) in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atoms having non-shared electron pairs in the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6'(P-Bqn)2BPy), thereby stabilizing the composite material. As a result, as shown in FIG. Figure 3 As shown, the positive electrostatic potential is primarily distributed on the metal (Li) and the first organic compound (Pyrrd-Phen), while the negative electrostatic potential is primarily distributed on the second organic compound (6,6'(P-Bqn)2BPy). Furthermore, the electrostatic potential around the nitrogen atoms with unshared electron pairs in the pyridine and benzo[h]quinazoline rings of the second organic compound (6,6'(P-Bqn)2BPy) is negative, while the electrostatic potential around the metal (Li) is positive. Furthermore, the Mulliken partial charge of this Li atom is +0.691e in atomic units.

[0100] [Estimation of SOMO energy level or stability energy] Next, quantum chemical calculations are used to estimate the stability energy and the SOMO energy level formed when a metal or metal compound, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings that are bonded or fused to each other to have a total of three or more heteroatoms interact with each other.

[0101] As a quantum chemical calculation program, Gaussian09 is used. The calculation is performed using SGI8600 manufactured by HPE. First, density functional theory (DFT) is used to calculate the most stable structure of the first organic compound, the second organic compound and the metal or metal compound in the ground state, the composite material of the first organic compound and the metal or metal compound, the composite material of the second organic compound and the metal or metal compound, and the composite material of the first organic compound, the second organic compound and the metal or metal compound in the ground state. 6-311G (d, p) and LanL2DZ are used as basis functions, and B3LYP is used as a functional function. Then, the stability energy is calculated based on the difference between the total energy of the composite material of the organic compound and the metal or metal compound and the total energy of the organic compound monomer and the total energy of the metal or metal compound monomer. In other words, (stability energy) = (total energy of the composite material of the organic compound and the metal or metal compound) - (total energy of the organic compound monomer) - (total energy of the metal or metal compound monomer) holds true.

[0102] The calculation results of the following composite material are shown below: lithium (Li) is used as the metal or metal compound, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as: Pyrrd-Phen) is used as the first organic compound, and 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as: 6,6'(P-Bqn)2BPy) is used as the second organic compound. In addition, for comparison, calculation results are shown for the following composite materials: a composite material using lithium (Li) as a metal or metal compound, pyrrd-Phen as a first organic compound, and 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (NBphen) as a second organic compound instead of 6,6'(P-Bqn)2BPy; a composite material using lithium (Li) and pyrrd-Phen; a composite material using lithium (Li) and 6,6'(P-Bqn)2BPy; and a composite material using lithium (Li) and NBphen. Note that 6,6'(P-Bqn)2BPy is a second organic compound that includes two or more heteroaromatic rings that are bonded or fused to each other and contain a total of three or more heteroatoms. NBphen, on the other hand, is an organic compound that includes two or more heteroaromatic rings that are bonded or fused to each other, but have a total number of heteroatoms of less than three.

[0103] [Table 1]

[0104] [Table 2]

[0105] As can be seen from the above table, the absolute value of the negative value of the stability energy of the composite material of lithium (Li), the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy) of one embodiment of the present invention is large. This means that: compared with the case where the organic compound and the metal or metal compound do not interact, the energy is more stable when the organic compound and the metal or metal compound interact. The SOMO energy level formed at this time is higher than the HOMO energy level of each of the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy), the difference with each LUMO energy level is small and the electron injection property is excellent, so it is preferred. Note that the energy levels of the SOMO energy level, HOMO energy level, and LUMO energy level in the table are values ​​obtained by calculation, and sometimes their absolute values ​​are different from those actually measured.

[0106] On the other hand, although not as good as the above-mentioned composite material of lithium (Li), the first organic compound (Pyrrd-Phen) and the second organic compound (6,6'(P-Bqn)2BPy), the stabilization energy of the composite material of lithium (Li), the first organic compound (Pyrrd-Phen) and NBphen is also negative, and the energy is more stable when the organic compound and the metal interact compared to the case where the organic compound and the metal do not interact.

[0107] Furthermore, the stabilization energy of the composite material of lithium (Li) and the first organic compound (Pyrrd-Phen) is a negative value, but the composite material obtained by adding the second organic compound to the composite material is more stable.

[0108] Furthermore, according to Table 1, the composite material of lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a relatively low SOMO level of -2.88 eV. Meanwhile, the composite material containing the first organic compound (Pyrrd-Phen) in addition to lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a relatively high SOMO level of -2.32 eV, resulting in excellent electron injection properties. Furthermore, while the composite material of lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a stability energy of -3.07 eV, the composite material containing the first organic compound (Pyrrd-Phen) in addition to lithium (Li) and the second organic compound (6,6'(P-Bqn)2BPy) has a more stable stability energy of -3.79 eV.

[0109] The composite material of lithium (Li) and NBphen has a SOMO energy level of -2.96 eV, which is relatively low among organic compounds used in light-emitting devices. On the other hand, the composite material containing a first organic compound (Pyrrd-Phen) in addition to lithium (Li) and NBphen has a higher SOMO energy level of -2.35 eV, resulting in excellent electron injection properties. Furthermore, the composite material of lithium (Li) and NBphen has a stability energy of -2.31 eV, but the composite material containing a first organic compound (Pyrrd-Phen) in addition to lithium (Li) and NBphen has a more stable stability energy of -3.67 eV.

[0110] That is, one embodiment of the present invention uses a composite material comprising a metal or a metal compound, a first organic compound including a π-electron-deficient heteroaromatic ring, and a second organic compound, which is stable and has excellent electron injection properties and is suitable for use in an intermediate layer. The second organic compound includes two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms.

[0111] Next, the calculation results of the following composite material are shown: a metal belonging to Group 11 or Group 13, specifically silver (Ag) or indium (In), is used as the metal or metal compound; Pyrrd-Phen is used as the first organic compound; and 4',4""-(1,4-phenylene)bis(2,2':6',2"-terpyridine) (abbreviated as tPy2P) or 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviated as 2Py3Tzn) is used as the second organic compound. In addition, as a comparison, the calculation results of the following composite material are also shown. Results: Silver (Ag) or indium (In) is used as the metal or metal compound, Pyrrd-Phen is used as the first organic compound, and NBphen is used instead of the second organic compound. Note that tPy2P and 2Py3Tzn are second organic compounds that include two or more heteroaromatic rings, which are bonded or fused to each other and contain a total of three or more heteroatoms. On the other hand, NBphen is an organic compound that includes two or more heteroaromatic rings, which are bonded or fused to each other, but have a total of less than three heteroatoms.

[0112] [Table 3]

[0113] [Table 4]

[0114] As shown in the table above, the composite material of a metal belonging to Group 11 or Group 13, a first organic compound, and a second organic compound according to one embodiment of the present invention is preferred because of its high stabilization energy and stable structure. Furthermore, the SOMO level formed in this manner is high and has excellent electron injection properties, making it also preferred.

[0115] Note that, considering the manufacturing process of light-emitting devices, in general, the EL layer of the light-emitting device, especially the intermediate layer, is often deposited using vacuum evaporation. As the material used at this time, it is preferred to use a material that can be easily vacuum-deposited, that is, a material with a low melting point. Metals belonging to Group 11 and Group 13 elements have low melting points and are therefore suitable for vacuum evaporation. Furthermore, metals belonging to Group 11 and Group 13 elements are preferred because they are stable to atmospheric oxygen and water. Furthermore, vacuum evaporation is preferred because it allows for easy mixing of metal atoms and organic compounds.

[0116] Ag and In can also be used as cathode materials. Using the same material for both the intermediate layer and the cathode is preferred because it simplifies the manufacture of light-emitting devices and reduces the manufacturing cost of light-emitting devices.

[0117] As can be seen from this, when a first organic compound including a π-electron-deficient heteroaromatic ring, a metal or metal compound, and a second organic compound including two or more heteroaromatic rings bonded or fused to each other, totaling three or more heteroatoms, interact, the first organic compound and the metal or metal compound act as electron donors for the second organic compound. In one embodiment of the present invention, by using this combination of materials in an intermediate layer, an intermediate layer can be formed that exhibits excellent electron injection properties and is resistant to atmospheric oxygen and water, as well as water and chemical solutions used in lithography processes. This results in a light-emitting device with reduced driving voltage and high luminous efficiency.

[0118] [Analysis of composite materials of metals or metal compounds and organic compounds] In the light-emitting device of one embodiment of the present invention, the intermediate layer can be measured as a composite material in which the first organic compound, the second organic compound, and the metal or the metal compound interact with each other.

[0119] Specifically, a film is prepared by mixing a first organic compound, a second organic compound, and a metal or metal compound in the same proportion as that used for an intermediate layer of a light-emitting device, and the film is measured using mass spectrometry methods such as time-of-flight secondary ion mass spectrometry (ToF-SIMS), laser desorption / ionization mass spectrometry (LDI-MS), and matrix-assisted laser desorption / ionization mass spectrometry (MALDI-MS).

[0120] According to the results of this mass spectrometry analysis, when the mass number of the first organic compound is M1, the mass number of the second organic compound is M2, and the mass number of the metal or metal compound is M3, positive ions with a mass-to-charge ratio of m / z M1+M2+M3 or M1+M2+M3+1 can be detected. Furthermore, when these mass spectrometry methods are used to measure positive ions, ions originating from the compounds contained in the film, substituents released from the compounds, compounds from which substituents have been released, and their associations are detected. Therefore, for example, when the mass number of the metal released from the metal compound is M31, positive ions with m / z M1+M2+M31 or M1+M2+M31+1 can be detected.

[0121] <Structure of the middle layer> Next, the detailed structure of the intermediate layer that can be used for the light-emitting device 130a and the light-emitting device 130b will be described.

[0122] <<First Floor>> The first layer (first layer 161a and first layer 161b) located on the anode side of the intermediate layer is preferably a mixed layer or stacked layer containing a metal or metal compound, a first organic compound, and a second organic compound (details of which will be described later). The combination of the metal or metal compound and the first organic compound interacts to form a donor energy level (SOMO or HOMO), thereby acting as an electron donor for the second organic compound having electron-transporting properties.

[0123] In other words, the metal or metal compound serves as a donor that supplies electrons to the second organic compound serving as an electron acceptor. When the first layer is composed of only the second organic compound serving as an electron acceptor and the metal or metal compound serving as a donor, the metal or metal compound becomes unstable due to the electron donation.

[0124] Therefore, when the first layer of one embodiment of the present invention contains an organic compound having an electron-donating group in addition to the metal or metal compound serving as a donor and the organic compound serving as an electron acceptor, an interaction occurs, thereby forming a stable structure. Due to this stable structure, the first layer of one embodiment of the present invention is prevented from degrading even when exposed to the atmosphere or undergoes a photolithography process, and can therefore be suitably used in light-emitting devices.

[0125] Specifically, if Figure 4 As shown, when a first organic compound (Hid2Phen) having an electron-donating group is contained in addition to a metal (Li) serving as a donor and a second organic compound (6,6'(P-Bqn)2BPy) serving as an electron acceptor, Li, which becomes unstable due to donating electrons to 6,6'(P-Bqn)2BPy (arrows in the figure), forms a donor level with Hid2Phen, thereby 6,6'(P-Bqn)2BPy, Li, and Hid2Phen becoming stable as a composite material.

[0126] By using a layer having these combinations in the first intermediate layer, electrons generated in the first layer can be easily injected into the first light-emitting unit. Alternatively, electrons generated in the second intermediate layer (second layer 162a and second layer 162b) located on the cathode side can be easily injected into the first light-emitting unit. This facilitates electron injection into the first light-emitting unit, thereby reducing the driving voltage of the light-emitting device and improving the luminous efficiency.

[0127] When a stack comprising a metal or a metal compound, a first organic compound and a second organic compound is used as the first layer on the anode side in the intermediate layer, the layer comprising the metal or the metal compound is preferably located on the cathode side compared to the layer comprising at least one of the first organic compound and the second organic compound. When the metal is located on the cathode side compared to the first organic compound or the second organic compound comprising a heteroaromatic ring and having electron transportability, electrons are more easily injected into the first light-emitting unit, thereby further reducing the driving voltage of the light-emitting device and further improving the luminous efficiency. In addition, a mixed layer comprising a metal or a metal compound, a first organic compound and a second organic compound is preferably used for the first layer. By using the metal or the metal compound, the first organic compound and the second organic compound as a mixed layer, it is easy for these substances to interact with each other, whereby the first organic compound and the metal or the metal compound act as electron donors (electron donors) to the second organic compound, so the electron injection barrier from the second light-emitting unit side to the first light-emitting unit side can be further reduced. Thus, it is easier to inject electrons into the first light-emitting unit, so the driving voltage of the light-emitting device can be further reduced and the luminous efficiency can be further improved. Furthermore, by using a metal or metal compound, a first organic compound, and a second organic compound as a mixed layer, a layer that is less susceptible to crystallization can be formed compared to a stacked structure. Therefore, when a portion of the organic compound layer is processed using lithography, a layer that is less susceptible to crystallization can be formed even when affected by atmospheric oxygen or water, or by chemical solutions or water during the process. This prevents an increase in the driving voltage or a decrease in the current efficiency of the light-emitting device due to crystallization of the intermediate layer. Therefore, compared to a stacked structure, the use of a mixed layer makes it suitable for use as an intermediate layer in a light-emitting device where a portion of the organic compound layer is processed using lithography.

[0128] <Metal or Metal Compound> As the metal or metal compound, a typical metal or transition metal or a compound thereof can be used. As the metal compound, for example, there are metal oxides, metal nitrides, metal oxynitrides formed by adding nitrogen to metal oxides, or metal oxynitrides formed by adding oxygen to metal nitrides. Among them, metal oxides are preferred because they are stable in the atmosphere and have little deterioration and are also easy to handle. However, due to their stability, even if metal oxides are used instead of alkali metal compounds in existing light-emitting devices, it is difficult to obtain the same characteristics as alkali metal compounds, and therefore it is impossible to obtain an organic EL device with characteristics that can withstand actual use. On the other hand, in one embodiment of the present invention, an organic EL device can be obtained that has good characteristics even when a stable metal compound such as a metal oxide is used.

[0129] As typical metals, alkali metals such as Li, Na, K, and Cs (Group 1 elements), alkaline earth metals such as Mg, Ca, and Ba (Group 2 elements), Group 12 elements such as Zn, earth metals such as Al and In (Group 13 elements), Group 14 elements such as Sn, or compounds thereof can be used.

[0130] When an alkali metal or alkaline earth metal or a compound thereof is used as the metal or metal compound, the donor energy level formed by the interaction with the first organic compound can be a high energy level, which can easily supply electrons to the second organic compound. As a result, the electrons generated in the intermediate layer can be smoothly injected and transferred to the electron transport layer, and a light-emitting device with a low driving voltage and high light efficiency can be provided, so it is preferred.

[0131] As transition metals, Group 3 elements including Y and lanthanide elements such as 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 can be used. Transition metals are preferred because of their low reactivity with atmospheric components such as water and oxygen.

[0132] Among the above-mentioned metals, it is more preferable to use a metal belonging to an odd-numbered group (Group 1, Group 3, Group 5, Group 7, Group 9, Group 11, or Group 13). Among these odd-numbered group transition metals, metals having one electron (unpaired electron) in the outermost orbital are particularly preferred because they easily form a SOMO with the first organic compound.

[0133] Metals with low melting points that can be deposited by vacuum deposition are preferred because they easily form mixed layers with organic compounds. Specifically, for example, metals belonging to Groups 11 and 13 have low melting points and are therefore suitable for vacuum deposition. Furthermore, metals belonging to Groups 11 and 13 are preferred because they are stable to atmospheric oxygen and water.

[0134] <First Organic Compound> As the first organic compound, an organic compound including a π-deficient electron heteroaromatic ring can be used. In addition, in order for the first organic compound to interact with the metal or metal compound and act as an electron donor (electron donor) to the second organic compound, the π-deficient electron heteroaromatic ring preferably has a non-shared electron pair, and the non-shared electron pair preferably has an electron donor property. That is, the first organic compound preferably includes a basic π-deficient electron heteroaromatic ring. In addition, nitrogen has a high electronegativity and is therefore easy to interact with a metal or a metal compound. In addition, since nitrogen can form a conjugated bond in an organic compound, an organic compound with high carrier transport properties can be achieved by using nitrogen for molecules, especially for heteroaromatic rings. Therefore, the first organic compound preferably includes a heteroaromatic ring containing nitrogen. Note that the heteroaromatic ring is more preferably an even-numbered ring such as a six-membered ring or an eight-membered ring. By adopting this structure, the non-shared electron pair on nitrogen does not involve conjugation and is therefore easy to interact with a metal or a metal compound. In addition, in order to smoothly inject and transport electrons from the intermediate layer to the electron transport layer, the first organic compound preferably has electron transport properties. Specifically, for example, the first organic compound preferably includes a pyridine ring.

[0135] In addition, the first organic compound is preferably a material comprising two or more π-electron-deficient heteroaromatic rings having non-shared electron pairs and the two or more π-electron-deficient heteroaromatic rings are bonded or fused to each other. Thus, when the metal or metal compound interacts with the first organic compound and the second organic compound as a bidentate ligand or a multidentate ligand, it becomes stable, so that an intermediate layer that is not easily degraded even after a photolithography process accompanied by atmospheric exposure can be formed. Therefore, even after a photolithography process accompanied by atmospheric exposure of the EL layer, the electrons generated in the intermediate layer can be smoothly injected and transferred to the adjacent electron transport layer, thereby making it possible to utilize the photolithography process to manufacture a series light-emitting device in which the rise in driving voltage is suppressed, the luminous efficiency is high and the reliability is high. Specifically, for example, the first organic compound preferably includes a heteroaromatic ring comprising two or more pyridine rings. Among them, an organic compound having a bipyridine skeleton is preferred because: its nitrogen atom is easily coordinated with the metal and is therefore easy to interact with the metal or metal compound.

[0136] Furthermore, the phenanthroline ring is preferred due to its rigidity and high stability. In particular, among the phenanthroline rings, the two nitrogen atoms in the organic compound having a 1,10-phenanthroline ring can coordinate to the metal, and thus easily interact with the metal or metal compound, making it preferred.

[0137] Furthermore, the first organic compound may have a structure in which a plurality of phenanthroline rings are linked by a single bond or via a divalent group. Specific examples of the divalent group include an alkylene group and an arylene group.

[0138] An alkylene group represents a divalent group obtained by removing two hydrogen atoms from an alkane. Specific examples of the alkylene group include divalent groups having a structure obtained by removing one hydrogen atom from the above-mentioned specific examples of the alkyl group.

[0139] An arylene group represents a divalent group formed by removing two hydrogen atoms from an aromatic hydrocarbon. Specific examples include divalent groups having a structure in which one hydrogen atom is removed from the above-mentioned specific examples of aryl groups. The arylene group may further have a substituent, and specific examples of such substituents include an alkyl group, an alkoxy group, and a phenyl group.

[0140] In addition, the first organic compound preferably has an electron-donating substituent. Thus, the first organic compound can have a high HOMO energy level and a high LUMO energy level, thereby increasing the difference between the LUMO energy level of the first organic compound and the LUMO energy level of the second organic compound. Furthermore, when the metal or metal compound, the first organic compound, and the second organic compound interact, the intermediate layer can be further stabilized, thereby forming an intermediate layer that is not easily degraded even after a photolithography process accompanied by atmospheric exposure. Therefore, even after a photolithography process accompanied by atmospheric exposure of the EL layer, electrons generated in the intermediate layer can be smoothly injected and transported to the adjacent electron transport layer, thereby suppressing the increase in the driving voltage, and a tandem light-emitting device with high luminous efficiency and high reliability can be manufactured using the photolithography process.

[0141] In addition, as the first organic compound, it is more preferred to use an organic compound comprising a phenanthroline ring with an electron donating group. In particular, by introducing an electron donating group on 1,10-phenanthroline ring, the electron density of the phenanthroline ring can be improved and the efficiency of the interaction with the metal or metallic compound can be improved. Furthermore, it is preferred that at least one of positions 4 and 7 of the 1,10-phenanthroline ring has an electron donating group. By introducing an electron donating group on positions 4 and 7, the electron density of the nitrogen-atoms at positions 1 and 10 of the para position can be improved. In addition, the steric hindrance around the nitrogen-atoms at positions 1 and 10 can be avoided, and the electron density around this can be improved. Therefore, it is possible to easily interact with a metal or metallic compound, so it is preferred.

[0142] As the specific example of the electron-donating group, alkyl, alkoxy, aryloxy, alkylamino, arylamino, heterocyclic amino etc. can be enumerated.But, the electron-donating group preferably introduced on the π-deficient electron type heteroaromatic ring such as phenanthroline ring is not limited thereto.As long as it is by introducing the base that can improve the electron density of the π-deficient electron type heteroaromatic ring on the π-deficient electron type heteroaromatic ring such as phenanthroline ring, it is possible to use it as the electron-donating group.In addition, the electron-donating group can also be introduced into the π-deficient electron type heteroaromatic ring such as phenanthroline ring through the arylene group such as phenylene, and the arylene group is preferably p-phenylene.

[0143] Alkyl refers to an alkane (Cn H 2n+2 ) is a monovalent group obtained by removing one hydrogen atom. Specific examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, neohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl, and 2,3-dimethylbutyl.

[0144] An alkoxy group represents a monovalent group having a structure in which an alkyl group is bonded to an oxygen atom. Specific examples of the alkoxy group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentoxy group, an isopentoxy group, a sec-pentoxy group, a tert-pentoxy group, a neopentoxy group, an n-hexoxy group, an isohexoxy group, a sec-hexoxy group, a tert-hexoxy group, and a neohexoxy group.

[0145] An aryloxy group represents a monovalent group having a structure in which an aryl group is bonded to an oxygen atom. An aryl group represents a monovalent group formed by removing a hydrogen atom from one of the ring carbon atoms of a monocyclic or polycyclic aromatic compound. Specific examples of the aryloxy group include a phenoxy group, an o-tolyloxy group, an m-tolyloxy group, a p-tolyloxy group, a mesityloxy group, an o-biphenyloxy group, an m-biphenyloxy group, a p-biphenyloxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, and a 2-fluorenyloxy group. The aryloxy group may further have a substituent, and specific examples of such a substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0146] Alkylamino groups represent monovalent groups in which one or two alkyl groups are bonded to the nitrogen atom of a primary or secondary amine, with one hydrogen atom removed. Specific examples of alkylamino groups include dimethylamino and diethylamino groups.

[0147] An arylamino group represents a monovalent group formed 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, bis(α-naphthyl)amino, and bis(m-tolyl)amino. The arylamino group may further have a substituent, and specific examples of such substituents include alkyl groups, alkoxy groups, and phenyl groups.

[0148] Furthermore, an amino group having a structure in which both an alkyl group and an aryl group are bonded to a nitrogen atom may be referred to as an alkylamino group or an arylamino group. Specific examples of such an amino group include N-methyl-N-phenylamino group and the like.

[0149] A heterocyclic amino group represents a monovalent group formed by removing a hydrogen atom from one of the nitrogen atoms forming a ring of a heterocyclic amine. Note that, herein, a heterocyclic amine refers to a monocyclic or polycyclic heterocyclic compound, and represents a compound in which at least one of the ring atoms is a nitrogen atom bonded to a hydrogen atom. Specific examples of heterocyclic amino groups include groups represented by the following structural formulas (R-1) to (R-26). Note that the heterocyclic amino group may further have a substituent, and specific examples of such a substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0150] [Chemical Formula 5]

[0151] Note that, when the heterocyclic amino group has aromaticity and the non-shared electron pair of nitrogen atom contributes to aromaticity, compared with the case where the non-shared electron pair of nitrogen atom does not contribute to aromaticity, the electron donating property to the phenanthroline ring is sometimes reduced. Therefore, in the above-mentioned heterocyclic amino group, it is more preferred to use the heterocyclic amino group in which the non-shared electron pair of nitrogen atom does not contribute to aromaticity. Specifically, the base represented by structural formula (R-1), structural formula (R-2), structural formula (R-3), structural formula (R-4), structural formula (R-5), structural formula (R-8), structural formula (R-9), structural formula (R-10), structural formula (R-12), structural formula (R-14), structural formula (R-15), structural formula (R-16), structural formula (R-17) or (R-21) is more preferred as an electron donating group. Among them, the groups represented by structural formula (R-3), structural formula (R-4), structural formula (R-8) or structural formula (R-21) have high electron donating properties and can further increase the electron density of the phenanthroline ring, so they are preferred.

[0152] Specific examples of the electron-donating group include groups represented by the following structural formulas (R-27) and (R-28).

[0153] [Chemical Formula 6]

[0154] Note that the organic compound containing a π-electron-deficient heteroaromatic ring that can be used as the first organic compound may also have both the above-mentioned electron-donating group and a substituent other than the above-mentioned electron-donating group. Specific examples of substituents that can be introduced into the π-electron-deficient heteroaromatic ring other than the above-mentioned electron-donating group include aryl groups. Specific examples of aryl groups include phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, and 2-fluorenyl. The aryl group may also have a substituent, and specific examples of such substituents include alkyl, alkoxy, and phenyl groups.

[0155] Furthermore, the first organic compound may have a structure in which a plurality of phenanthroline rings are linked by a single bond or via a divalent group. Specific examples of the divalent group include an alkylene group and an arylene group.

[0156] Specific examples of organic compounds including a π-electron-deficient heteroaromatic ring that can be used as the first organic compound are shown by structural formulas (100) to (112). Note that the organic compound that can be used as the first organic compound is not limited thereto.

[0157] [Chemical Formula 7]

[0158] Structural formula (100) is 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen). Structural formula (103) is 4,7-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline (abbreviated as 4,7hpp2Phen). Structural formula (105) is 2,2'-(1,3-phenylene)bis[9-(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline] (abbreviated as mhppPhen2P). Structural formula (106) is 2-(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-9-phenyl-1,10-phenanthroline (abbreviated as 9Ph-2hppPhen). Structural formula (107) is 2,9-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidin-1-yl)-1,10-phenanthroline (abbreviated as 2,9hpp2Phen). Structural formula (111) is 4,7-bis(2,3,3a,4,5,6,7,7a-octahydro-1H-isoindol-2-yl)-1,10-phenanthroline (abbreviated as Hid2Phen). Structural formula (112) is 4,7-bis[4-(1-pyrrolidinyl)phenyl]-1,10-phenanthroline (abbreviated as: PrdP2Phen).

[0159] In addition, when the negative minimum value of the electrostatic potential (ESP: Electrostatic Potential) of the first organic compound is small (the negative absolute value is large), the stability of the interaction with the metal or metal compound is improved, so it is preferred. In organic compounds including π-electron-deficient heteroaromatic rings, the electrostatic potential around the nitrogen atom of the π-electron-deficient heteroaromatic ring tends to have a negative value, but by introducing an electron-donating group on 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 is increased). Electrostatic potential refers to the interaction energy of a positive point charge with a unit charge and the electron distribution of a molecule. In addition, the value of the electrostatic potential also varies according to the threshold value of the electron density distribution. In order to improve the efficiency of the interaction with the metal, the minimum value of the electrostatic potential of the first organic compound is preferably less than the minimum value of the electrostatic potential of the phenanthroline ring without a substituent (large in the negative direction). Specifically, when the threshold value of the electron density distribution in the atomic unit system is 0.0004e / a0 3 When the minimum value of the electrostatic potential is preferably -0.085E h (E h represents the Hartree energy (1E h =27.211eV)) or less, more preferably -0.090E h In addition, when the threshold value of electron density distribution is 0.003e / a0 3 When the minimum value of the electrostatic potential is preferably -0.12E h Below, more preferably -0.13E h the following.

[0160] <<Estimating the Properties of the First Organic Compound Using Quantum Chemical Calculations>> The minimum value of the electrostatic potential (ESP) of the above-mentioned organic compounds that can be used as the first organic compound was estimated by quantum chemical calculation.

[0161] Gaussian 09 was used as a quantum chemical calculation program. Calculations were performed using an SGI8600 manufactured by HPE. Density functional theory (DFT) was used to calculate the most stable structure of the first organic compound in the ground state. 6-311G (d, p) was used as the basis function, and B3LYP was used as the functional.

[0162] The following table shows the analysis results of the electrostatic potential in the ground state of the first organic compound. The electrostatic potential refers to the interaction energy between a positive point charge with a unit charge and the electron distribution of a molecule. In addition, the value of the electrostatic potential varies depending on the threshold value of the electron density distribution. The following table shows the analysis results in atomic units, with the threshold value of the density distribution set to 0.0004e / a. 3 or 0.003e / a03 The electrostatic potential of the electron density distribution when .

[0163] [Table 5] Minimum value of ESP (density threshold = 0.0004) Minimum value of ESP (density threshold = 0.003) Pyrrd-Phen(100) -0.091 -0.12 DMeAPhen(101) -0.089 -0.12 p-MeO-Phen(102) -0.089 -0.12 4,7hpp2Phen(103) -0.096 -0.13 CzPhen(104) -0.072 -0.10 mhppPhen2P(105) -0.057 -0.096 9Ph2hppPhen(106) -0.057 -0.096 2,9hpp2Phen(107) -0.061 -0.097 Hid2Phen(111) -0.094 -0.13 PrdP2Phen(112) -0.094 -0.13 Bphen -0.083 -0.11 mPPhen2P -0.057 -0.094 NBphen -0.053 -0.093 Phen -0.081 -0.11

[0164] Note that the organic compounds represented by structural formulas (100) to (107), structural formula (111) and structural formula (112), Bphen, mPPhen2P, NBphen and Phen in the table shown below as organic compounds that can be used as the first organic compound are shown.

[0165] [Chemical Formula 8]

[0166] As can be seen from the above table, the threshold value of the electron density distribution in the atomic unit system in the organic compounds represented by structural formula (100) to structural formula (103), structural formula (111) and structural formula (112) is 0.0004e / a0 3 The minimum ESP value is -0.085E h On the other hand, it is known that the minimum ESP value of the organic compounds represented by the structural formula (104) to the structural formula (107) is greater than -0.085E h .

[0167] It can be seen that the organic compounds represented by structural formulas (100) to (103), (111) and (112) have electron-donating groups at positions 4 and 7 of the 1,10-phenanthroline ring and therefore have the most preferred values.

[0168] The organic compound represented by structural formula (104) has electron-donating groups at the 4- and 7-positions of the 1,10-phenanthroline ring, but uses an N-carbazolyl group as the electron-donating group. In the N-carbazolyl group, the unshared electron pair of the nitrogen atom contributes to aromaticity. Therefore, compared to groups in which the unshared electron pair of the nitrogen atom does not contribute to aromaticity, the electron-donating capacity to the phenanthroline ring is reduced. Consequently, the minimum ESP value is less likely to decrease, leading to the above-mentioned results.

[0169] The organic compounds represented by structural formula (105) to structural formula (107) are organic compounds having electron-donating groups at the 2-position and 9-position of the 1,10-phenanthroline ring. The electron-donating groups introduced at the 2-position and 9-position have low electron-donating properties to the nitrogen at the 1-position and 10-position of the phenanthroline ring. Therefore, the electron-donating groups in the 1,10-phenanthroline ring are preferably located at the 4-position and 7-position.

[0170] Note that the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound. This facilitates electron donation from the donor level formed by the first organic compound and the metal or metal compound to the second organic compound. Furthermore, the second organic compound preferably has electron-transporting properties, and to this end, the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound.

[0171] For example, the LUMO energy level of the first organic compound is preferably greater than -3.0 eV and less than -2.0 eV, more preferably greater than -2.7 eV and less than -2.0 eV. In addition, the LUMO energy level of the second organic compound is preferably greater than -3.0 eV and less than -2.0 eV, more preferably greater than -3.0 eV and less than -2.5 eV. As a result, electrons can be easily supplied to the second organic compound from the donor energy level formed by the first organic compound and the metal or metal compound. In addition, electron transport in the second organic compound is facilitated thereby.

[0172] Note that the HOMO and LUMO levels of organic compounds are generally estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values ​​of different compounds, it is preferable to use values ​​estimated by the same measurement.

[0173] Furthermore, when the first organic compound has high basicity, the interaction with holes significantly reduces the hole transport property of the first layer 161a of the intermediate layer 160a, thereby preventing holes from being transported from the first layer 161a to the second layer 162a. This is preferred because a highly efficient light-emitting device can be obtained. Specifically, the acidity coefficient pKa is preferably 8 or greater, more preferably 10 or greater, and even more preferably 12 or greater.

[0174] When the acidity coefficient pKa of an organic compound is unknown, the acidity coefficient pKa of each skeleton of the organic compound can be investigated, and the largest acidity coefficient pKa among them can be regarded as the acidity coefficient pKa of the organic compound.

[0175] Alternatively, the acidity coefficient can be obtained by calculation. For example, the acidity coefficient pKa can be obtained by the following calculation method.

[0176] As the initial structure of the molecular structure of each molecule used as a calculation model, the most stable structure (singlet ground state) obtained by first-principles calculation was adopted.

[0177] As the first principles calculations above, use Jaguar, a quantum chemical calculation software manufactured by Inc., calculates the most stable structure in the singlet ground state using density functional theory (DFT). 6-31G** is used as the basis function and B3LYP-D3 is used as the functional function. Maestro GUI manufactured by Inc. performs conformational analysis and sampling using Mixed torsional / Low-mode sampling.

[0178] In the pKa calculation, one or more atoms in each molecule were designated as basic sites. The Macro Model was used to explore the stable structure of the protonated molecule in water. The lowest-energy conformer obtained through conformational exploration using the OPLS2005 force field was used. The Jaguar pKa calculation module was used to optimize the structure using B3LYP / 6-31G*. Single-point calculations were then performed using cc-pVTZ(+). The pKa value was calculated using empirical corrections for functional groups. For molecules with one or more atoms designated as basic sites, the largest value obtained was used as the pKa value. The resulting pKa values ​​are shown.

[0179] The pKa of acidity coefficient of 2,9hpp2Phen is 13.35, the pKa of acidity coefficient of 4,7hpp2Phen is 13.42, the pKa of acidity coefficient of Pyrrd-Phen is 11.23, the pKa of acidity coefficient of mPPhen2P is 5.16, the pKa of acidity coefficient of NBphen is 5.59, and the pKa of acidity coefficient of Bphen is 5.62.

[0180] <Second Organic Compound> The first layer of the intermediate layer includes, in addition to the metal or metal compound and the first organic compound, a second organic compound, wherein the second organic compound includes two or more heteroaromatic rings bonded or fused to each other, and the two or more heteroaromatic rings include a total of three or more heteroatoms. Furthermore, the second organic compound functions as a multidentate ligand, whereby two or more of the three or more heteroatoms interact with the metal or metal compound.

[0181] Including a second organic compound can improve heat resistance and electron transport properties. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring included in the first organic compound is a first π-electron-deficient heteroaromatic ring and the π-electron-deficient heteroaromatic ring included in the second organic compound is a second π-electron-deficient heteroaromatic ring, the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring preferably include different rings.

[0182] In addition, as the second π-electron-deficient heteroaromatic ring, it is preferred to use a heteroaromatic ring having an azole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton and a heteroaromatic ring having a triazine skeleton, etc., among which the diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or triazine ring is electrochemically stable and has high electron transport properties, so it is preferred.

[0183] As the organic compound used as the second organic compound, for example, an organic compound represented by the following general formula (G1-1) can be used.

[0184] [Chemical Formula 9]

[0185] In the above general formula (G1-1), A 1 、A 2 and A 3 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 、A 2 and A 3 They may also form a condensed ring.

[0186] Organic compounds represented by the general formula (G1-1) have conjugated double bonds formed by the N-N-C-N sequence on the heteroaromatic ring and function as tridentate or higher ligands that interact with metals or metal compounds. Organic compounds with this structure readily interact with metals or metal compounds and are therefore suitable for use in intermediate layers.

[0187] In the above general formula (G1-1), as A 1 、A 2 and A 3 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by , for example, a heteroaromatic ring having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthridine ring (anthyridine ring), azafluoranthene ring), a heteroaromatic ring having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that A 1 、A 2 and A 3 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms is not limited thereto. 1 、A2 and A 3 They can also form fused rings with each other. For example, A 1 With A 2 They may be bonded to each other to form a phenanthroline ring.

[0188] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G2-1) can be used.

[0189] [Chemical Formula 10]

[0190] In the general formula (G2-1), X 1 To X 6 Each independently represents carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 4 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. Alternatively, in the general formula (G2-1), X 1 To X 6 They may be bonded to each other directly or through carbon atoms to form a condensed ring.

[0191] As an organic compound represented by the general formula (G2-1), an organic compound having a function of interacting with a metal or a metal compound as a tridentate or higher ligand more preferably includes at least one of a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, and a heteroaromatic ring having a triazine skeleton. These rings have excellent electrochemical stability, so a light-emitting device with good reliability can be provided. In addition, due to the excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0192] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G3-1) can be used.

[0193] [Chemical Formula 11]

[0194] In the general formula (G3-1), X 1 To X 4Each independently represents carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 6 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0195] In addition, as an organic compound that can be used as the second organic compound, an organic compound represented by the following general formula (G4-1) can be used.

[0196] [Chemical Formula 12]

[0197] In the general formula (G4-1), X 1 To X 5 Each independently represents carbon (C) or nitrogen (N), carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 5 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0198] Organic compounds having a pyridine skeleton are preferred because they have a high LUMO energy level. 1 and X 2 When carbon is represented, the organic compound has a pyridine skeleton and can form a composite material with a high SOMO level when interacting with a metal or a metal compound. In other words, an organic compound having a pyridine ring and capable of interacting as a tridentate or higher ligand can form an intermediate layer with high electron injection properties by interacting with a metal or a metal compound.

[0199] In addition, organic compounds having a diazine skeleton or a triazine skeleton are preferred because they are electrochemically stable and have high electron transport properties. 1 and X2 When at least one of the rings represents nitrogen, the organic compound has a diazine or triazine skeleton and can form a stable composite material with high electron transport properties when interacting with a metal or metal compound. In other words, an organic compound having a diazine ring or triazine ring that functions as a tridentate or higher ligand can form a highly reliable intermediate layer by interacting with a metal or metal compound.

[0200] In addition, as the organic compound used as the second organic compound, for example, an organic compound represented by the following general formula (G1-2) can be used.

[0201] [Chemical Formula 13]

[0202] In the above general formula (G1-2), A 1 and A 2 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A 1 and A 2 They can also form fused rings with each other, A 1 Contains two or more nitrogen atoms.

[0203] Organic compounds represented by the general formula (G1-2) have conjugated double bonds formed by the N groups on the heteroaromatic ring arranged in the order of NCCN, and function as bidentate or higher-order ligands that interact with metals or metal compounds. Organic compounds with this structure readily interact with metals or metal compounds and are therefore suitable for use in intermediate layers.

[0204] In the above general formula (G1-2), as A 1 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by , for example, a heteroaromatic ring having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring) and the like. As the heteroaromatic ring represented by A 2The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by , for example, a heteroaromatic ring having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthridine ring, azafluoranthene ring), a heteroaromatic ring having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that A 1 and A 2 The substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms is not limited thereto. 1 and A 2 They can also form fused rings with each other. For example, A 1 With A 2 They may be bonded to each other to form a pyrazinoquinoxaline ring.

[0205] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G2-2) can be used.

[0206] [Chemical Formula 14]

[0207] In the general formula (G2-2), X 1 To X 4 At least one of them represents nitrogen (N), and the rest independently represent carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 4 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. Alternatively, in the general formula (G2-2), X 1 To X 4 They may be bonded to each other directly or through carbon atoms to form a condensed ring.

[0208] As in the organic compound represented by the general formula (G2-2), the organic compound having a function of interacting with a metal or a metal compound as a bidentate or higher ligand preferably includes a heteroaromatic ring having a diazine skeleton or a heteroaromatic ring having a triazine skeleton. These rings have excellent electrochemical stability, so a light-emitting device with good reliability can be provided. In addition, due to the excellent electron transport properties, a light-emitting device with a reduced driving voltage can be provided.

[0209] In addition, as the organic compound used as the second organic compound, an organic compound represented by the following general formula (G3-2) can be used.

[0210] [Chemical Formula 15]

[0211] In the general formula (G3-2), X 1 and X 2 One of the represents nitrogen (N), and the other represents carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 6 Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0212] In addition, as an organic compound that can be used as the second organic compound, an organic compound represented by the following general formula (G4-2) can be used.

[0213] [Chemical Formula 16]

[0214] In the general formula (G4-2), X 1 To X 3 At least one of them represents nitrogen (N), and the rest independently represent carbon (C) or nitrogen (N), and the carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and R 1 to R 5Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0215] Organic compounds having a pyridine skeleton are preferred because they have a high LUMO energy level. 1 and X 2 and X represented by the general formula (G3-2) 1 When carbon is represented, the organic compound has a pyridine skeleton and can form a composite material with a high SOMO level when interacting with a metal or a metal compound. In other words, an organic compound having a pyridine ring and capable of interacting as a bidentate or higher ligand can form an intermediate layer with high electron injection properties by interacting with a metal or a metal compound.

[0216] In addition, organic compounds having a diazine skeleton or a triazine skeleton are preferred because they are electrochemically stable and have high electron transport properties. 1 and X 2 At least one of and X represented by the general formula (G3-2) 1 When represents nitrogen, the organic compound has a diazine or triazine skeleton, and thus can form a stable composite material with high electron transport properties when interacting with a metal or metal compound. In other words, an organic compound having a diazine or triazine ring that functions as a bidentate or higher ligand can form a highly reliable intermediate layer by interacting with a metal or metal compound.

[0217] More specific examples of organic compounds used as the second organic compound and organic compounds including a heteroaromatic ring of the above-mentioned general formulas (G1-1) to (G4-2) are shown below from general formulas (250) to (267).

[0218] [Chemical Formula 17]

[0219] [Chemical Formula 18]

[0220] In general formulae (250) to (267), R 11 to R 172Each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0221] In addition, examples of substituents that can be used in the above-mentioned general formulas (G1-1) to (G4-2) and general formulas (250) to (267) include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, aryl groups having 6 to 30 carbon atoms, arylene groups having 6 to 30 carbon atoms, and heteroaryl groups having 1 to 30 carbon atoms. Note that some or all of the hydrogen atoms may be deuterium. In addition, the groups that can be used in the above-mentioned general formulas are not limited to the following specific examples.

[0222] Specific examples of the alkyl group having 1 to 10 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, neohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl, 2,3-dimethylbutyl, and 1-ethylhexyl.

[0223] Specific examples of the cycloalkyl group having 3 to 10 carbon atoms include cyclopropyl, cyclobutyl, methylcyclobutyl, cyclopentyl, methylcyclopentyl, isopropylcyclopentyl, tert-butylcyclopropyl, cyclohexyl, methylcyclohexyl, isopropylcyclohexyl, tert-butylcyclohexyl, cycloheptyl, methylcycloheptyl, isopropylcycloheptyl, cyclooctyl, methylcyclooctyl, isopropylcyclohexyl, cyclononyl, methylcyclononyl, cyclodecyl, and adamantyl.

[0224] Specific examples of the aryl group having 6 to 30 carbon atoms include phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, fluorenyl, 9,9-dimethylfluorenyl, spirobifluorenyl, phenanthrenyl, anthracenyl, and fluoranthenyl. When the aryl group having 6 to 30 carbon atoms has a substituent, the substituent includes an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a phenyl group.

[0225] Specific examples of the arylene group having 6 to 30 carbon atoms include phenylene, biphenyl-diyl, naphthalene-diyl, fluorene-diyl, acenaphthene-diyl, anthracene-diyl, phenanthrene-diyl, terphenyl-diyl, triphenylene-diyl, naphthacene-diyl, benzanthracene-diyl, pyrene-diyl, and spirobi[9H-fluorene]-diyl. When the arylene group having 6 to 30 carbon atoms has a substituent, the substituent includes an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a phenyl group.

[0226] A heteroaryl group having 1 to 30 carbon atoms refers to a monovalent group formed by removing one hydrogen atom from one of the ring carbon atoms of a monocyclic or polycyclic heteroaromatic compound having 1 to 30 carbon atoms. Specific examples of heteroaryl groups having 1 to 30 carbon atoms include 1,3,5-triazin-2-yl, 1,2,4-triazin-3-yl, pyrimidin-4-yl, pyrazin-2-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, benzonaphthofuranyl, benzonaphthothiophenyl, indolocarbazolyl, benzofuranocarbazolyl, benzothiophenocarbazolyl, indenocarbazolyl, and dibenzocarbazolyl. When the heteroaryl group has a substituent, the substituent may include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and a phenyl group.

[0227] Specific examples of the organic compound used as the second organic compound and the organic compounds represented by the above-mentioned general formula (G1-1) to general formula (G4-2) are shown below.

[0228] [Chemical Formula 19]

[0229] [Chemical Formula 20]

[0230] [Chemical Formula 21]

[0231] Note that the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound. This facilitates electron donation from the donor level formed by the first organic compound and the metal or metal compound to the second organic compound. Furthermore, the second organic compound preferably has electron-transporting properties, and to this end, the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound.

[0232] The LUMO energy level of the second organic compound is preferably -3.0 eV to -2.0 eV, more preferably -3.0 eV to -2.5 eV. The LUMO energy level of the first organic compound is preferably -3.0 eV to -2.0 eV, more preferably -2.7 eV to -2.0 eV.

[0233] This facilitates the supply of electrons from the donor level formed by the first organic compound and the metal or metal compound to the second organic compound, and also facilitates the transport of electrons in the second organic compound.

[0234] In one embodiment of the present invention, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound, and the absolute value of the difference between the LUMO energy levels of the first organic compound and the second organic compound is preferably 0.20 eV to 0.50 eV. The absolute value of the difference between the LUMO energy levels of the first organic compound and the second organic compound is more preferably 0.25 eV to 0.50 eV, further preferably 0.30 eV to 0.50 eV, further preferably 0.35 eV to 0.50 eV, and even more preferably 0.40 eV to 0.50 eV.

[0235] That is, when the LUMO energy level of the first organic compound is expressed as "LUMO1 (eV)" and the LUMO energy level of the second organic compound is expressed as "LUMO2 (eV)", LUMO2 preferably satisfies the following inequality (1). LUMO1-0.50≤LUMO2≤LUMO1-0.20···(1)

[0236] Furthermore, it is more preferable that LUMO2 satisfies the following inequality (2). LUMO1-0.50≤LUMO2≤LUMO1-0.25· · · (2)

[0237] Furthermore, it is more preferable that LUMO2 satisfies the following inequality (3). LUMO1-0.50≤LUMO2≤LUMO1-0.30··· (3)

[0238] Furthermore, it is more preferable that LUMO2 satisfies the following inequality (4). LUMO1-0.50≤LUMO2≤LUMO1-0.35··· (4)

[0239] Furthermore, it is more preferable that LUMO2 satisfies the following inequality (5). LUMO1-0.50≤LUMO2≤LUMO1-0.40··· (5)

[0240] When the LUMO2 is within the above range, a light-emitting device according to one embodiment of the present invention can achieve a tandem light-emitting device with low driving voltage and excellent characteristics, regardless of whether or not a photolithography step involving atmospheric exposure of the EL layer is performed. Furthermore, a highly reliable tandem light-emitting device can be achieved.

[0241] As the second organic compound, an organic compound having electron transport properties can be used. As the organic compound having electron transport properties, an organic compound having an electron mobility of 1×10- - 7 cm 2 It is more preferable to use a material having an electron mobility of 1×10 -6 cm 2 In addition, any substance other than the above may be used as long as it has a higher electron-transporting property than a hole-transporting property.

[0242] The second organic compound preferably has a carbon number of 25 to 100. This carbon number allows for an organic compound with good sublimation properties, thereby suppressing thermal decomposition of the organic compound during vacuum deposition and achieving good material utilization efficiency.

[0243] In addition, it is preferable to use a second organic compound having a glass transition temperature T g The organic compound is 100° C. or higher. This allows the intermediate layer to have high heat resistance and not be easily crystallized. Therefore, a layer that is not easily crystallized even when a portion of the organic compound layer is processed using lithography can be realized.

[0244] Furthermore, the second organic compound may have a pKa value of less than 4. This reduces the water solubility of the second organic compound, thereby improving its resistance to water and chemicals used in lithography processes.

[0245] Organic compounds with a pKa of less than 4 have lower water solubility than organic compounds with a pKa of 4 or greater. Furthermore, using an organic compound with a pKa of less than 4 as the second organic compound improves the water resistance of the intermediate layer compared to using an organic compound with a pKa of 4 or greater. Furthermore, during the manufacturing process, problems such as the intermediate layer peeling off from other layers can be suppressed. This can prevent defects that could cause defects in the light-emitting device.

[0246] When the acidity coefficient pKa of an organic compound is unknown, the acidity coefficient pKa of each skeleton of the organic compound can be investigated, and the largest acidity coefficient pKa among them can be regarded as the acidity coefficient pKa of the organic compound.

[0247] Furthermore, when the first layer contains a second organic compound in addition to the metal or metal compound and the first organic compound, interaction between the materials occurs efficiently, which can be confirmed by measuring the spin density using electron spin resonance (ESR).

[0248] For example, the spin density measured by ESR of a film comprising a metal or metal compound and a first organic compound is preferably higher than the spin density measured by ESR of a film comprising a metal or metal compound and a second organic compound. Furthermore, the spin density measured by ESR of a film comprising a metal or metal compound, a first organic compound, and a second organic compound is preferably higher than the spin density measured by ESR of a film comprising only any two of the metal or metal compound, the first organic compound, and the second organic compound. In this case, it can be confirmed that the interaction between the materials is efficiently generated.

[0249] More specifically, in a film containing a metal or a metal compound and a first organic compound, the spin density of a signal observed at a g value of approximately 2.00 by an electron spin resonance method is preferably 5×10 16 spins / cm 3 More than 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 More than 1×10 19 spins / cm 3 More than 1×10 20 spins / cm 3 In this case, it can be confirmed that the interaction between the materials is efficiently generated in the layer containing the combination of the metal or metal compound and the first organic compound. Alternatively, in the film containing the metal or metal compound, the first organic compound and the second organic compound, for example, the spin density of the signal observed at a g value of 2.00 by the electron spin resonance method is preferably 5×10 16 spins / cm 3 More than 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3More than 1×10 19 spins / cm 3 More than 1×10 20 spins / cm 3 In this case, it can be confirmed that the interaction between the materials in the layer containing the combination of the metal or metal compound, the first organic compound, and the second organic compound occurs more efficiently than in the layer containing only two of these materials. In this case, the spin density of the mixed film containing the metal or metal compound and the second organic compound, for example, caused by the signal observed at a g value of 2.00 by the electron spin resonance method, is 2×10 16 spins / cm 3 Hereinafter, the spin density of a mixed film containing the first organic compound and the second organic compound, for example, resulting from a signal observed at a g value of approximately 2.00 by electron spin resonance, is 2×10 16 spins / cm 3 the following.

[0250] In the first layer, the metal or metal compound is preferably 0.1 or more and 10 or less of the first organic compound (or the sum of the first organic compound and the second organic compound) in a molar ratio, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. Alternatively, it is preferably 0.01 or more and 0.3 or less, more preferably 0.02 or more and 0.2 or less, and further preferably 0.05 or more and 0.1 or less in a volume ratio. By including a first layer comprising a metal or metal compound and a first organic compound (or a first organic compound and a second organic compound) in such a ratio, an intermediate layer with good electron injection properties can be provided. In addition, the second organic compound may not be used, but in the case of using the second organic compound, the first organic compound is preferably 0.1 or more and 10 or less of the second organic compound in a volume ratio, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less. By mixing the first organic compound and the second organic compound in such a ratio, an intermediate layer with good electron transport properties can be provided. In addition, by using an organic compound with good thermal properties of high Tg as the second organic compound, a highly reliable organic EL device can be provided.

[0251] In addition, the thickness of the first layer is preferably from 2 nm to 20 nm, more preferably from 5 nm to 10 nm. When the first layer has a laminated structure of a layer of a metal or metal compound and a layer comprising a first organic compound, the thickness of the metal or metal compound layer is preferably from 0.1 nm to 5 nm, more preferably from 0.2 nm to 2 nm. In addition, when the first layer has a laminated structure of a layer of a metal or metal compound and a layer comprising a first organic compound, the thickness of the layer comprising the first organic compound is preferably from 2 nm to 20 nm, more preferably from 5 nm to 10 nm.

[0252] By using the second organic compound, a composite material obtained by mixing a metal or a metal compound, a first organic compound, and a second organic compound can function well, thereby providing a light-emitting device exhibiting high luminous efficiency.

[0253] <<Second Floor>> When the first layer of the intermediate layer is a mixed layer or a stacked layer structure comprising a metal or metal compound, a first organic compound, and a second organic compound, the second layer is preferably a layer comprising a third organic compound and a fourth organic compound (details of which will be described later). This is preferred because it allows for good hole injection into the upper light-emitting layer.

[0254] <Third Organic Compound> The third organic compound preferably uses an organic compound having hole transport properties. As the organic compound having hole transport properties, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, high molecular weight compounds (oligomers, dendrimers, polymers, etc.) can be used. As the organic compound having hole transport properties, it is preferred to use an organic compound having a hole mobility of 1×10 -6 cm 2 / Vs or more. The organic compound having hole transport properties is preferably a compound containing a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. The fused aromatic hydrocarbon ring is preferably an anthracene ring, a naphthalene ring, or the like. In addition, the π-electron-rich heteroaromatic ring is preferably a fused aromatic ring having at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton, and specifically preferably a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are further fused with an aromatic ring or a heteroaromatic ring.

[0255] Such an organic compound having hole-transporting properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine containing a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Note that when these organic compounds having hole-transporting properties contain an N,N-bis(4-biphenyl)amino group, they are preferred because they allow the production of light-emitting devices with long lifetimes.

[0256] Specific examples of the organic compound having a hole-transporting property include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4"-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[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(6)), and N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine. Furan-8-amine (abbreviated as BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviated as BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviated as ThBA1BP), 4-(2-naphthyl)-4',4"-diphenyltriphenylamine (abbreviated as BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4"-diphenyltriphenylamine (abbreviated as BBAβNBi), 4,4'-diphenyl-4"-(6; 1'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB), 4,4'-diphenyl-4"-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB-03), 4,4'-diphenyl-4"-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviated as: BBAPβNB-03), 4,4'-diphenyl-4"-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B), 4,4'-diphenyl-4"-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B-03), 4,4'-diphenyl-4"-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviated as: BBAβNαNB ), 4,4'-diphenyl-4"-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviated as: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviated as: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviated as: αNBB1BP), 4,4'-Diphenyl-4"-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviated as YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tri(biphenyl-4-yl)amine (abbreviated as YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviated as YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as 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-fluorene-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-phenylfluorene-9-yl) )triphenylamine (abbreviated as: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviated as: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3 -yl) triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluoren-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(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, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, etc.

[0257] In addition, as materials with hole-transporting properties, the following aromatic amine compounds can be used: N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc.

[0258] <Fourth Organic Compound> The fourth organic compound is preferably a material that has an acceptor property for the third organic compound. As the acceptor, an organic compound having an electron-withdrawing group (halogen, cyano, etc.) is preferably used, and more preferably an organic compound having four or more halogen groups, four or more cyano groups, or a combination of four or more halogen groups and cyano groups is used. Specific 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), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H- In particular, compounds such as HAT-CN in which an electron-withdrawing group is bonded to a fused aromatic ring containing multiple heteroatoms are thermally stable and therefore preferred. In addition, [3]radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluorine groups and cyano groups) are particularly preferred because they have very high electron-accepting properties. Specifically, the following can be mentioned: α, α', α"-1, 2,3-cyclopropane trimethylene tris[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α"-1,2,3-cyclopropane trimethylene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α,α',α"-1,2,3-cyclopropane trimethylene tris[2,3,4,5,6-pentafluorophenylacetonitrile], etc. As the acceptor substance, in addition to the above-mentioned organic compounds, metal oxides, especially transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used.

[0259] In addition, in the second layer, it is preferable to observe a signal observed by electron spin resonance. For example, the spin density of the signal observed near the g value of 2.00 is preferably 1×10 17 spins / cm 3 More than 1×10 18 spins / cm 3 More than 1×10 19 spins / cm 3 As a result, the second layer can be used as a charge generation layer. In addition, a light-emitting device with low driving voltage and high efficiency can be manufactured.

[0260] <<Third Floor>> Furthermore, a third layer may be provided between the first layer and the second layer of the intermediate layer in order to facilitate electron transfer between the two layers.

[0261] The third layer contains a substance having electron transport properties and can prevent the interaction between the first layer and the second layer to smoothly transfer electrons. The LUMO energy level of the substance having electron transport properties contained in the third layer 163 is preferably equal to the LUMO energy level of the acceptor substance in the second layer 162 and the LUMO energy level of the layer ( Figure 5B The LUMO energy level of the organic compound contained in the first electron transport layer 114_1 in the first light-emitting unit 501 is preferably between -5.0 eV and -3.0 eV. Specifically, the LUMO energy level of the substance with electron transport properties used in the third layer 163 is greater than -5.0 eV, preferably greater than -5.0 eV and less than -3.0 eV, more preferably greater than -4.30 eV and less than -3.00 eV, and further preferably greater than -4.30 eV and less than -3.30 eV. In this case, electrons generated in the second layer 162 can be easily injected into the first layer 161, thereby suppressing the increase in the driving voltage of the light-emitting device. In addition, as the substance with electron transport properties used in the third layer 163, a phthalocyanine material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0262] Specifically, perylene tetracarboxylic acid derivatives such as bisquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorobisquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), 3,4,9,10-perylenetetracarboxylic acid diimide (abbreviation: PTCDI), 3,4,9,10-perylenetetracarboxylic acid-bis-benzimidazole (abbreviation: PTCBI), (C60-Ih)[5,6]fullerene (abbreviation: C60), (C70-D5h)[5,6]fullerene (abbreviation: C70), etc. can be used. In addition, compounds having a heterocyclic ring-containing heterophene skeleton can be suitably used in the cyclophene skeleton. As such compounds, organic compounds having a phthalocyanine skeleton such as phthalocyanine (abbreviation: H2Pc) can be used. Alternatively, metal phthalocyanines containing copper, zinc, cobalt, iron, chromium, nickel, and the like, such as copper phthalocyanine (CuPc), zinc phthalocyanine (ZnPc), cobalt phthalocyanine (CoPc), iron phthalocyanine (FePc), tin phthalocyanine (SnPc), oxotin phthalocyanine (SnOPc), oxotitanium phthalocyanine (TiOPc), and oxovanadium phthalocyanine (VOPc), and their derivatives can be used. In particular, phthalocyanine metal complexes such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorobisquinoxalino[2,3-a:2',3'-c]phenazine, are preferred. CuPc and ZnPc are particularly preferred because they are inexpensive and have excellent properties. Furthermore, ZnPc has a low diffusion coefficient for silicon, reducing the likelihood of metal diffusion into the semiconductor and affecting semiconductor properties, making it particularly suitable for use in display devices using silicon semiconductors.

[0263] The thickness of the third layer 163 is preferably greater than or equal to 1 nm and less than or equal to 10 nm, and more preferably greater than or equal to 2 nm and less than or equal to 5 nm.

[0264] The structure described in this embodiment can be used in combination with the structures described in other embodiment modes as appropriate.

[0265] Implementation Method 2 In this embodiment, another structure of a light-emitting device according to one embodiment of the present invention is described.

[0266] Figure 5A A light-emitting device 130 as an example of a light-emitting device according to one embodiment of the present invention is shown. The light-emitting device 130 includes an organic compound layer 103 having a light-emitting layer 113 between a first electrode 101 having an anode and a second electrode 102 having a cathode.

[0267] Figure 5BLight-emitting device 130 is another example of a light-emitting device according to one embodiment of the present invention. Light-emitting device 130 is a tandem light-emitting device. Light-emitting device 130 includes a first light-emitting unit 501 having a first light-emitting layer 113_1 , a second light-emitting unit 502 having a second light-emitting layer 113_2 , and an intermediate layer 160 as the organic compound layer 103 .

[0268] Note that in this embodiment, a light-emitting device including one intermediate layer 160 and two light-emitting units is described as an example. However, a light-emitting device including n (n is an integer greater than or equal to 1) intermediate layers and n+1 light-emitting units may also be used.

[0269] For example, Figure 5C The light-emitting device 130 shown is an example of a tandem light-emitting device, where n is 2 and includes, as the organic compound layer 103, a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, and a third light-emitting unit 503 including a third light-emitting layer 113_3. The color gamut of light emitted by the light-emitting layers in each light-emitting unit can be the same or different. Furthermore, the light-emitting layers can have either a single-layer structure or a stacked-layer structure. For example, white light can be emitted by the first and third light-emitting units emitting light in the blue region, while the light-emitting layer in the stacked-layer structure of the second light-emitting unit emitting light in the red and green regions.

[0270] For example, Figure 5D The light-emitting device 130 shown is an example of a tandem light-emitting device, where n is 3. The organic compound layer 103 includes a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, a third light-emitting unit 503, a third intermediate layer 160_3, and a fourth light-emitting unit 504 including a fourth light-emitting layer 113_4. The color gamut of light emitted by the light-emitting layers in each light-emitting unit can be the same or different. Furthermore, the light-emitting layer can have either a single-layer structure or a stacked-layer structure. For example, the four light-emitting units can have the following structures: a structure in which any three are blue (B) and the remaining one is green (G); a structure in which any two are blue (B) and the remaining two are yellow (Y); a structure in which any one is red (R), another is green (G), and the remaining two are blue (B), etc.

[0271] The light-emitting device 130 may also be a light-emitting device manufactured using lithography technology. When a light-emitting device manufactured using lithography technology is used, at least the light-emitting layer 113 or the second light-emitting layer 113_2 and the organic compound layer closer to the first electrode 101 than these layers are processed simultaneously, so that the ends of these layers are roughly aligned in the vertical direction.

[0272] Note that the organic compound layer 103 may include other functional layers in addition to the light-emitting layer. Figure 5A The organic compound layer 103 includes a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115 in addition to the light-emitting layer 113. Furthermore, the first light-emitting unit 501 and the second light-emitting unit 502 may include other functional layers in addition to the light-emitting layer. Figure 5B The following structure is shown: the first light-emitting unit 501 is provided with a hole injection layer 111, a first hole transport layer 112_1, and a first electron transport layer 114_1 in addition to the first light-emitting layer 113_1. The second light-emitting unit 502 is provided with a second hole transport layer 112_2, a second electron transport layer 114_2, and an electron injection layer 115 in addition to the second light-emitting layer 113_2. Note that the structure of the organic compound layer 103 in the present invention is not limited to this. None of the above layers may be provided, and other layers may be provided. Typical examples of other layers include carrier blocking layers (hole blocking layers, electron blocking layers), exciton blocking layers, and the like.

[0273] Next, the structure of the light emitting device 130 other than the intermediate layer 160 will be described.

[0274] <<Structure of the First Electrode>> The first electrode 101 is an electrode including an anode. The first electrode 101 may also have a stacked structure, in which case the layer in contact with the organic compound layer 103 is used as the anode. The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a large work function (specifically, 4.0 eV or more). Specifically, for example, indium oxide-tin oxide (ITO: Indium Tin Oxide), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO), etc. may be cited. Although these conductive metal oxide films are usually deposited by sputtering, they can also be formed by applying a sol-gel method. As an example of a formation method, a method of forming indium oxide-zinc oxide by sputtering using a target material in which 1 wt% to 20 wt% of zinc oxide is added to indium oxide may be cited. In addition, a target material in which 0.5 wt% to 5 wt% of tungsten oxide and 0.1 wt% to 1 wt% of zinc oxide are added to indium oxide can be used to form indium oxide (IWZO) by sputtering. In addition, as materials for the anode, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd) or nitrides of metal materials (for example, titanium nitride) can be cited. In addition, graphene can also be used as a material for the anode. In addition, by using the second layer 162 in the above-mentioned intermediate layer 160 as a layer in contact with the anode (typically a hole injection layer), it is possible to select an electrode material without taking into account the work function.

[0275] <<Structure of Hole Injection Layer>> The hole injection layer 111 is in contact with the anode and has the function of facilitating hole injection into the organic compound layer 103 (first light-emitting unit 501). The hole injection layer 111 can be formed using phthalocyanine compounds such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (abbreviated as CuPc); aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and 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) / (polystyrenesulfonic acid) (abbreviated as PEDOT / PSS).

[0276] Alternatively, the hole injection layer 111 may be formed using a substance having electron acceptor properties. As the substance having acceptor properties, the substances listed above as the acceptor substances used in the second layer 162 of the intermediate layer 160 can be used in the same manner.

[0277] Alternatively, the hole injection layer 111 may be formed using the hole transport material used for the second layer 162 in the intermediate layer 160 .

[0278] Note that in the hole-injection layer 111, the organic compound with hole-transport properties used in the composite material is preferably a substance with a relatively low HOMO energy level of -5.7 eV to -5.4 eV. When the organic compound with hole-transport properties used in the composite material has a relatively low HOMO energy level, holes are easily injected into the hole-transport layer, and a light-emitting device with a long lifespan can be easily obtained. Furthermore, when the organic compound with hole-transport properties used in the composite material has a relatively low HOMO energy level, hole induction is appropriately suppressed, thereby achieving a light-emitting device with a longer lifespan.

[0279] By forming the hole injection layer 111, hole injection properties can be improved, thereby obtaining a light-emitting device with low driving voltage.

[0280] Furthermore, among substances having acceptor properties, organic compounds having acceptor properties can be easily deposited by vapor deposition and are therefore easy-to-use materials.

[0281] In addition, since the second layer 162 in the intermediate layer 160 is used as a hole injection layer, the second light emitting unit 502 is not provided with a hole injection layer, but the second light emitting unit 502 may also be provided with a hole injection layer.

[0282] <<Structure of Hole Transport Layer>> The hole transport layer (the first hole transport layer 112_1 and the second hole transport layer 112_2) is formed by including an organic compound having a hole transport property. The organic compound having a hole transport property preferably has a 1×10 -6 cm 2 / Vs and above hole mobility.

[0283] Examples of the hole-transporting material 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-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP). , compounds having an aromatic amine skeleton, such as 4,4'-diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviated as PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviated as PCBASF);1,3-Bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (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 (abbreviated as: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviated as βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviated as βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviated as BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl] ]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole compounds having a carbazole skeleton, such as oxazole, 9-(2-naphthyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviated as PCCzTp), 9,9'-bi(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, and 9-(triphenyl-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole;Compounds having a thiophene skeleton, such as 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV); and compounds having a furan skeleton, such as 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among these, compounds having an aromatic amine skeleton and a carbazole skeleton are preferred because they have good reliability and high hole-transport properties, and contribute to lowering the driving voltage. Furthermore, the organic compounds having hole-transport properties listed as composite materials for the hole-injection layer 111 can be appropriately used as materials constituting the hole-transport layer.

[0284] <<Structure of Light Emitting Layer>> The light-emitting layer (the light-emitting layer 113, the first light-emitting layer 113_1, and the second light-emitting layer 113_2) preferably contains a light-emitting substance and a host material. Note that the light-emitting layer may also contain other materials. Alternatively, two layers with different compositions may be stacked.

[0285] The light-emitting substance may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or other light-emitting substances.

[0286] In the light-emitting layer, materials that can be used as the fluorescent substance include, for example, the following substances. Note that other fluorescent substances can also be used.

[0287] Examples thereof include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-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 (abbreviated as: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviated as: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviated as: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl)phenyl] -2-anthryl) triphenylamine (abbreviated as: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated as: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviated as: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl) triphenylamine (abbreviated as: PCBAPA), N,N"-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(1,2-diphenyl-2-yl)-1,2-diphenyl ... (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] -2,7,10,15-tetramine (abbreviated as DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviated as 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPA), 9,10-bis(2-biphenyl)-2-(N,N',N'-triphenyl-1,4-phenylenediamine-N-yl)anthracene (abbreviated as 2DPABPhA), 9,10-bis(biphenyl-2 -yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviated as 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviated as DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviated as DPQd), rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenylnaphthacene (abbreviated as BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malononitrile (abbreviated as DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethene 1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as DCM2), N,N,N',N'-tetrakis(4-methylphenyl)naphthacene-5,11-diamine (abbreviated as p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviated as p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2 ,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malononitrile (abbreviated as: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviated as: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho[1,[2-d]furan-8-amine] (abbreviated as 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10FrA2Nbf(IV)-02). In particular, fused aromatic diamine compounds such as pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 are preferred due to their excellent hole-trapping properties, high luminescence efficiency, and good reliability.

[0288] When a phosphorescent substance is used as a light-emitting substance in the light-emitting layer, examples of usable materials include the following substances.

[0289] Examples include organometallic iridium complexes having a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Mptz)3]), and tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(iPrptz-3b)3]); tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [Ir (Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]), etc. having an organometallic iridium complex with a 1H-triazole skeleton; fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviated as [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me)3]), etc. having an imidazole skeleton; and bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ] iridium (III) tetrakis (1-pyrazolyl) borate (abbreviated as: FIr6), bis [2- (4', 6'-difluorophenyl) pyridinium-N, C 2’] iridium (III) picolinate (abbreviated as: FIrpic), bis{2-[3', 5'-bis(trifluoromethyl)phenyl]pyridinium-N, C 2’ Iridium(III) picolinate (abbreviated as [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium (III) acetylacetonate (FIracac), are compounds that emit blue phosphorescence and have a peak emission wavelength of 450 to 520 nm.

[0290] In addition, tris(4-methyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinyl]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl -6-(2-methylphenyl)-4-phenylpyrimidinyl]iridium(III) (abbreviated as [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinyl)iridium(III) (abbreviated as [Ir(dppm)2(acac)]), etc.; (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinyl)iridium(III) (abbreviated as [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinyl)iridium(III) (abbreviated as [Ir(mppr-iPr)2(acac)]), etc.; tris(2-phenylpyridinyl-N,C 2’ )iridium (III) (abbreviated as [Ir(ppy)3]), bis(2-phenylpyridinium-N, C 2’ )iridium(III) acetylacetonate (abbreviated as [Ir(ppy)2(acac)]), bis(benzo[h]quinolinolato)iridium(III) acetylacetonate (abbreviated as [Ir(bzq)2(acac)]), tris(benzo[h]quinolinolato)iridium(III) (abbreviated as [Ir(bzq)3]), tris(2-phenylquinolinolato-N,C 2’)iridium (III) (abbreviated as [Ir(pq)3]), bis(2-phenylquinoline-N, C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridyl-κN]benzofuro[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5mtpy-d3)2(mbfpypy-d3)), Organometallic iridium complexes with a pyridine skeleton, such as [2-d3-methyl-(2-pyridyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(ppy)2(mdppy)); and rare earth metal complexes, such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]). These substances are mainly compounds that exhibit green phosphorescence and have an emission peak in the wavelength range of 500nm to 600nm. Furthermore, an organometallic iridium complex having a pyrimidine skeleton is particularly preferable because it has particularly excellent reliability and luminous efficiency.

[0291] In addition, organometallic iridium complexes having a pyrimidine skeleton include: (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinyl]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinyl](dipivaloylmethanyl)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinyl](dipivaloylmethanyl)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]); Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviated as [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethane)iridium(III) (abbreviated as [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]); tris(1-phenylisoquinoline-N,C 2’ )iridium (III) (abbreviated as [Ir(piq)3]), bis(1-phenylisoquinoline-N, C 2’ ) iridium(III) acetylacetonate (abbreviated as [Ir(piq)2(acac)]) and other organometallic iridium complexes having a pyridine skeleton; platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato][monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]). These substances are compounds that exhibit red phosphorescence and have an emission peak in the wavelength range of 600nm to 700nm. In addition, organometallic iridium complexes with a pyrazine skeleton can obtain red luminescence with good chromaticity.

[0292] Furthermore, in addition to the above-mentioned phosphorescent compounds, known phosphorescent compounds can be selected and used.

[0293] As TADF materials, fullerene and its derivatives, acridine and its derivatives, and eosin derivatives can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can also be used. As the metal-containing porphyrin, for example, there can be mentioned protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), protoporphyrin-tin fluoride complex (SnF2(Etio I)) and octaethylporphyrin-platinum chloride complex (PtCl2OEP) represented by the following structural formula.

[0294] [Chemical Formula 22]

[0295] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[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), The present invention also includes heterocyclic compounds containing one or both of π-electron-rich heteroaromatic rings and π-electron-deficient heteroaromatic rings, such as 5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthene-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridinium)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracenes]-10'-one (abbreviation: ACRSA). The heterocyclic compound has high electron transport and high hole transport properties due to including a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, so it is preferred. Among them, in the skeleton including the π-electron-deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) and the triazine skeleton are stable and have good reliability, so it is preferred. In particular, the acceptor properties of the benzofuranopyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuranopyrazine skeleton, and the benzothienopyrazine skeleton are high and have good reliability, so it is preferred. In addition, in the skeleton with a π-type electron-rich heteroaromatic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton and the pyrrole skeleton are stable and have good reliability, so it is preferred to have at least one of the above-mentioned skeletons. In addition, as the furan skeleton, a dibenzofuran skeleton is preferably used, and as the thiophene skeleton, a dibenzothiophene skeleton is preferably used. As the pyrrole skeleton, it is particularly preferred to use an indole skeleton, a carbazole skeleton, an indolecarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton. In a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, the electron donating property of the π-electron-rich heteroaromatic ring and the electron accepting property of the π-electron-deficient heteroaromatic ring are both high, and the energy difference between the S1 energy level and the T1 energy level becomes small, so that thermally activated delayed fluorescence can be efficiently obtained, so it is particularly preferred. Note that an aromatic ring bonded with an electron-withdrawing group such as a cyano group can also be used instead of a π-electron-deficient heteroaromatic ring. In addition, as a π-electron-rich skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. can be used.In addition, as the π-electron-deficient skeleton, a xanthene skeleton, a thioxanthenedioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane, boranthrene, an aromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanophenyl, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. can be used. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used to replace at least one of the π-electron-deficient heteroaromatic ring and the π-electron-rich heteroaromatic ring.

[0296] [Chemical Formula 23]

[0297] Alternatively, TADF materials can be used that are in thermal equilibrium between singlet and triplet excited states. These TADF materials have a short emission lifetime (excitation lifetime), thus suppressing efficiency degradation in high-brightness regions of light-emitting devices. Specifically, materials with the following molecular structures can be used.

[0298] [Chemical Formula 24]

[0299] TADF materials are materials with a small difference between the S1 and T1 energy levels and the ability to convert triplet excitation energy into singlet excitation energy through anti-intersystem crossing. Therefore, they can up-convert triplet excitation energy into singlet excitation energy (anti-intersystem crossing) using minimal thermal energy, efficiently generating singlet excited states. Furthermore, they can convert triplet excitation energy into luminescence.

[0300] The exciplex formed by two substances in an excited state has the function of a TADF material that can convert triplet excitation energy into singlet excitation energy due to the extremely small difference between the S1 energy level and the T1 energy level.

[0301] Note that as an indicator of the T1 level, a phosphorescence spectrum observed at a low temperature (e.g., 77 K to 10 K) can be used. Regarding TADF materials, when the wavelength energy of an extrapolated line obtained by cutting a line at the short-wavelength tail of the fluorescence spectrum is taken as the S1 level and the wavelength energy of an extrapolated line obtained by cutting a line at the short-wavelength tail of the phosphorescence spectrum is taken as the T1 level, it is preferred that the difference between S1 and T1 be 0.3 eV or less, more preferably 0.2 eV or less.

[0302] When a TADF material is used as a light-emitting substance, the S1 energy level of the host material is preferably higher than that of the TADF material. In addition, the T1 energy level of the host material is preferably higher than that of the TADF material.

[0303] As the host material of the light-emitting layer, various carrier transport materials such as a material having an electron-transporting property and / or a material having a hole-transporting property, and the above-mentioned TADF material can be used.

[0304] As the material having a hole-transporting property, the above-mentioned materials having a hole-transporting property can be used in the same manner.

[0305] As the material having an electron-transporting property, the above-mentioned materials having an electron-transporting property can be used in the same manner.

[0306] TADF materials that can be used as host materials can be the same as those listed above. When using a TADF material as a host material, the triplet excitation energy generated by the TADF material is converted to singlet excitation energy through reverse intersystem crossing and further transferred to the luminescent material, thereby improving the luminescence efficiency of the light-emitting device. In this case, the TADF material acts as an energy donor, and the luminescent material acts as an energy acceptor.

[0307] This is particularly effective when the luminescent material is a fluorescent material. Furthermore, in order to achieve high luminous efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent material. Furthermore, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent material.

[0308] Furthermore, it is preferable to use a TADF material that emits light at a wavelength that overlaps with the lowest-energy absorption band of the fluorescent substance. This allows for smooth transfer of excitation energy from the TADF material to the fluorescent substance, resulting in efficient emission.

[0309] In order to efficiently generate singlet excitation energy from triplet excitation energy via anti-intersystem crossing, carrier recombination is preferably generated in the TADF material. In addition, it is preferred that the triplet excitation energy generated in the TADF material is not transferred to the triplet excitation energy of the fluorescent material. For this reason, the fluorescent material preferably has a protective group around the luminophore (the skeleton that causes luminescence) possessed by the fluorescent material. As the protective group, it is preferred that a substituent not having a π bond is used. For example, it is preferably a saturated hydrocarbon, specifically, an alkyl group having 3 or more and 10 or less carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 or more and 10 or less carbon atoms, a trialkylsilyl group having 3 or more and 10 or less carbon atoms, and more preferably a plurality of protective groups. Since the substituent not having a π bond has almost no function of transporting carriers, it has almost no effect on carrier transport or carrier recombination, and the TADF material and the luminophore of the fluorescent material can be kept away from each other. Here, the luminophore refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminophore preferably has a π bond skeleton, preferably includes an aromatic ring, and preferably includes a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the luminophore include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, skeleton, triphenylene skeleton, tetracene skeleton, pyrene skeleton, perylene skeleton, coumarin skeleton, quinacridone skeleton, naphthobisbenzofuran skeleton, etc. In particular, the skeletons having naphthalene skeleton, anthracene skeleton, fluorene skeleton, Fluorescent substances having a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because they have high fluorescence quantum yields.

[0310] When a fluorescent light-emitting substance is used as a light-emitting substance, a material having an anthracene skeleton is preferably used as a host material. By using a substance having an anthracene skeleton as a host material of a fluorescent light-emitting substance, a light-emitting layer having high luminous efficiency and durability can be achieved. Among the substances having an anthracene skeleton used as a host material, substances having a diphenylanthracene skeleton (especially 9,10-diphenylanthracene skeleton) are chemically stable, so they are preferred. In addition, when the host material has a carbazole skeleton, the injection / transport properties of holes are improved, so it is preferred, but when a benzocarbazole skeleton having a benzene ring also fused to a carbazole skeleton is used, the HOMO is about 0.1eV higher than that of the host material having a carbazole skeleton and holes are easily injected, so it is more preferred. In particular, when the host material has a dibenzocarbazole skeleton, its HOMO is about 0.1eV higher than that of the host material having a carbazole skeleton, not only holes are easily injected, but also hole transport and heat resistance are improved, so it is preferred. Therefore, as a host material, a material having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton) is more preferred. Note that from the perspective of the hole injection / transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA), 9-phenyl-10-[4'-(9-phenyl-9H-fluoren-9-yl)phenyl]-9H-carbazole (abbreviated as CzPA),

[0015] anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), and the like. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred because they exhibit very good properties.

[0311] Alternatively, the host material can be a mixture of multiple substances. When using a mixed host material, it is preferred to mix a material with electron-transporting properties with a material with hole-transporting properties. By mixing materials with electron-transporting properties, the transport properties of the light-emitting layer 113 can be adjusted more easily, and the recombination zone can be more easily controlled. The weight ratio of the hole-transporting material to the electron-transporting material can be between 1:19 and 19:1.

[0312] Note that a phosphorescent substance may be used as part of the mixed material. When a fluorescent substance is used as the luminescent substance, the phosphorescent substance can function as an energy donor for supplying excitation energy to the fluorescent substance.

[0313] Furthermore, these mixed materials can also be used to form an exciplex. Selecting the mixed materials so that the exciplex forms light with a wavelength overlapping the absorption band on the lowest energy side of the luminescent substance is preferable because it facilitates energy transfer and allows for efficient luminescence. Furthermore, this structure also reduces the driving voltage, making it preferable.

[0314] Note that at least one of the materials forming the exciplex may be a phosphorescent substance. This allows efficient conversion of triplet excitation energy into singlet excitation energy via reverse intersystem crossing.

[0315] Regarding the combination of materials that efficiently form exciplexes, the HOMO energy level of the material having hole transport properties is preferably greater than the HOMO energy level of the material having electron transport properties. In addition, the LUMO energy level of the material having hole transport properties is preferably greater than the LUMO energy level of the material having electron transport properties. Note that the LUMO energy level and HOMO energy level of the material can be determined from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0316] Note that the formation of an exciplex can be confirmed, for example, by comparing the emission spectra of a material having hole transport properties, the emission spectra of a material having electron transport properties, and the emission spectra of a mixed film formed by mixing these materials. If the emission spectrum of the mixed film is observed to shift toward the longer wavelength side compared to the emission spectra of each material (or to have a new peak on the longer wavelength side), it indicates that an exciplex has been formed. Alternatively, by comparing the transient photoluminescence (PL) of a material having hole transport properties, the transient PL of a material having electron transport properties, and the transient PL of a mixed film formed by mixing these materials, if a difference in transient response is observed, such as a longer lifetime component or a larger ratio of delayed components in the transient PL lifetime of the mixed film compared to the transient PL lifetime of each material, it indicates that an exciplex has been formed. In addition, the above-mentioned transient PL can be referred to as transient electroluminescence (EL). In other words, by comparing the transient EL of a material having hole transport properties, the transient EL of a material having electron transport properties, and the transient EL of a mixed film of these materials, and observing the difference in transient response, the formation of an exciplex can be confirmed.

[0317] <<Structure of Electron Transport Layer>> The electron transport layer (electron transport layer 114, first electron transport layer 114_1, second electron transport layer 114_2) is a layer containing a substance having electron transport properties. The electron transport material preferably has an electron mobility of 1×10-1 at a square root of an electric field strength [V / cm] of 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 / Vs or more. In addition, as long as the electron transport property is higher than the hole transport property, substances other than the above can be used. As the above-mentioned organic compound, it is preferred to use an organic compound comprising a π-electron-deficient heteroaromatic ring. As an organic compound comprising a π-electron-deficient heteroaromatic ring, for example, it is preferred to use any one or more of an organic compound comprising a heteroaromatic ring having an azole skeleton, an organic compound comprising a heteroaromatic ring having a pyridine skeleton, an organic compound comprising a heteroaromatic ring having a diazine skeleton, and an organic compound comprising a heteroaromatic ring having a triazine skeleton.

[0318] As the organic compound with electron transport properties that can be used in the electron transport layer, the organic compound that can be used as the organic compound with electron transport properties in the first layer of the intermediate layer 160 can be used in the same manner. In particular, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, or organic compounds containing heteroaromatic rings having a triazine skeleton are preferred because they have 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, which helps reduce the driving voltage.

[0319] Furthermore, the electron transport layer preferably has an electron mobility of 1×10 -7 cm 2 / Vs or above and 5×10 -5 cm 2 / Vs or less. By reducing the transportability of electrons in the electron transport layer, the amount of electrons injected into the light-emitting layer can be controlled, thereby preventing the light-emitting layer from becoming in a state with too many electrons. When a composite material is used to form a hole injection layer, and the HOMO energy level of the material with hole transport properties in the composite material is a lower HOMO energy level of more than -5.7 eV and less than -5.4 eV, a long life can be obtained by adopting this structure, so it is particularly preferred. Note that at this time, the HOMO energy level of the material with electron transport properties is preferably more than -6.0 eV.

[0320] For example, as an electron transport material that can be used for an electron transport layer, a heteroaromatic compound can be used. Note that a heteroaromatic compound refers to a cyclic compound containing at least two different elements in the ring. Note that the ring structure includes a three-membered ring, a four-membered ring, a five-membered ring, a six-membered ring, etc., and is particularly preferably a five-membered ring or a six-membered ring, and the element contained in the heteroaromatic compound is preferably one or more of nitrogen, oxygen and sulfur, etc., in addition to carbon. It is particularly preferred to use a heteroaromatic compound containing nitrogen (nitrogen-containing heteroaromatic compound), preferably using a nitrogen-containing heteroaromatic compound or a π-electron-deficient heteroaromatic compound containing the nitrogen-containing heteroaromatic compound, etc., with high electron transport properties (electron transport material). The compound of embodiment 1 can be used as an electron transport material because it has electron transport properties.

[0321] Note that the electron transport material can use a material different from the material used for the light-emitting layer. Not all excitons generated by carrier recombination in the light-emitting layer can contribute to luminescence, and sometimes diffuse to layers in contact with or near the light-emitting layer. To avoid this phenomenon, the energy level (lowest singlet excitation energy level or lowest triplet excitation energy level) of the material used for the layer in contact with or near the light-emitting layer is preferably higher than that of the material used for the light-emitting layer. Therefore, when the electron transport material uses a material different from the material used for the light-emitting layer, a highly efficient device can be obtained.

[0322] Heteroaromatic compounds are organic compounds that include at least one heteroaromatic ring.

[0323] Note that the heteroaromatic ring includes any of a pyridine ring, a diazine ring, a triazine ring, and an azole ring. Furthermore, heteroaromatic rings including a pyrimidine ring, a pyrazine ring, or a pyridazine ring are included in the heteroaromatic ring including a diazine ring. Furthermore, heteroaromatic rings including an imidazole ring, a triazole ring, an oxadiazole ring, an oxazole ring, or a thiazole ring are included in the heteroaromatic ring including an azole ring.

[0324] The heteroaromatic ring includes a fused heteroaromatic ring having a fused ring structure. Note that examples of the fused heteroaromatic ring include a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a furadiazine ring, and a benzimidazole ring.

[0325] Note that, for example, among heteroaromatic compounds containing one or more of nitrogen, oxygen, sulfur, etc. in addition to carbon, as heteroaromatic compounds having a five-membered ring structure, there can be mentioned heteroaromatic compounds including an imidazole ring, heteroaromatic compounds including a triazole ring, heteroaromatic compounds including an oxazole ring, heteroaromatic compounds including an oxadiazole ring, heteroaromatic compounds including a thiazole ring, heteroaromatic compounds including a benzimidazole ring, and the like.

[0326] For example, among heteroaromatic compounds containing one or more of nitrogen, oxygen, and sulfur in addition to carbon, examples of heteroaromatic compounds having a six-membered ring structure include heteroaromatic compounds containing heteroaromatic rings such as pyridine rings, diazine rings (including pyrimidine rings, pyrazine rings, pyridazine rings, etc.), triazine rings, and azole rings. Note that heteroaromatic compounds having a bipyridine structure and heteroaromatic compounds having a terpyridine structure are also included in the examples of heteroaromatic compounds linked to a pyridine ring.

[0327] Furthermore, examples of heteroaromatic compounds having a fused ring structure part of which includes the above-mentioned six-membered ring structure include heteroaromatic compounds including fused heteroaromatic rings such as a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a phenanthroline ring, a furanodiazine ring (including a structure in which a furan ring of a furanodiazine ring is fused with an aromatic ring), and a benzimidazole ring.

[0328] Specific examples of heteroaromatic compounds having the above-mentioned five-membered ring structure (azole ring (including imidazole ring, triazole ring, oxadiazole ring), oxazole ring, thiazole ring, benzimidazole ring, etc.) include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3 ... (4-tert-Butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 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-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOS), etc.

[0329] Specific examples of the heteroaromatic compound having the above-mentioned six-membered ring structure (heteroaromatic ring such as pyridine ring, diazine ring, triazine ring) include heteroaromatic compounds having a heteroaromatic ring such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-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 (abbreviated as mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviated as mINc(II)PTzn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mTpBPTzn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviated as BP-SFTzn), 2,6-bis(4-naphthyl)piperidin -1-phenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as: 2,4NP-6PyPPm), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as: PCDBfTzn), 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), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: m Heteroaromatic compounds including heteroaromatic rings having a triazine ring, such as mFBPTzn, 4,6-bis[3-(phenanthrene-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-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalen-2-yl)-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8BP-4mDBtPBfpm, 9mDBtBPNfpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[ Heteroaromatic compounds including heteroaromatic rings having a diazine (pyrimidine) ring include 3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), and 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm). Note that the aromatic compounds including the above heteroaromatic rings include heteroaromatic compounds having fused heteroaromatic rings.

[0330] In addition, 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy), 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-carbazol-9-yl)phenyl]-2-phenyl Heteroaromatic compounds including heteroaromatic rings having a diazine (pyrimidine) ring, such as pyrimidine (abbreviation: 6mBP-4Cz2PPm); heteroaromatic compounds including heteroaromatic rings having a triazine ring, such as 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridinyl)-1,3,5-triazine (abbreviation: 2Py3Tz), and 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn).

[0331] Specific examples of the heteroaromatic compound having a fused ring structure partly including the above-mentioned six-membered ring structure (heteroaromatic compound having a fused ring structure) include bathophenanthroline (abbreviation: Bphen), bathocuproin (abbreviation: BCP), 2,9-di(naphth-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2,2'-biphenyl-4,4'-diylbis(9-phenyl-1,10-phenanthroline) (abbreviation: PPhen2BP), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2 mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]diphenyl Heteroaromatic compounds having a quinoxaline ring, such as 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), and 2mpPCBPDBq.

[0332] In addition to the above-mentioned heteroaromatic compounds, the following metal complexes can be used in the electron transport layer. Examples of such metal complexes include tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq3), Almq3, 8-hydroxyquinoline lithium (abbreviated as Liq), BeBq2, bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq), and metal complexes containing oxazole or thiazole rings, such as bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ).

[0333] In addition, as electron transport materials, polymer compounds such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used.

[0334] Furthermore, the electron transport layer is not limited to a single layer, and may have a structure in which two or more layers composed of the above-mentioned substances are stacked.

[0335] <<Structure of Electron Injection Layer>> As the electron injection layer 115, a layer containing an alkali metal, alkaline earth metal, rare earth metal, or compound or complex thereof, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-hydroxyquinoline-lithium (abbreviated as: Liq), or ytterbium (Yb), can also be provided. The electron injection layer 115 can be a layer in which an alkali metal, alkaline earth metal, or compound thereof is contained in a layer composed of a substance having electron transport properties, or an electron compound (electride). Examples of the electron compound include a substance obtained by adding electrons at a high concentration to a mixed oxide of calcium and aluminum.

[0336] Note that a layer containing an alkali metal or alkaline earth metal fluoride in a microcrystalline state (50 wt % or more) containing an electron-transporting substance (preferably an organic compound having a bipyridine skeleton) can also be used as the electron-injection layer 115. Since this layer has a low refractive index, a light-emitting device with improved external quantum efficiency can be provided.

[0337] The electron-injection layer 115 can use the organic compound of one embodiment of the present invention described in Embodiment 1. The electron-injection layer 115 may contain a substance having an electron-transport property in addition to the organic compound of one embodiment of the present invention described in Embodiment 1.

[0338] <<Structure of the Second Electrode>> The second electrode 102 is an electrode including a cathode. The second electrode 102 may also have a stacked structure, in which case the layer in contact with the organic compound layer 103 is used as a cathode. As a material forming the cathode, metals, alloys, conductive compounds, and mixtures thereof with a small work function (specifically, less than 3.8 eV) can be used. As specific examples of such cathode materials, there can be cited alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 in the periodic table, alloys containing them (MgAg, AlLi), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing them. However, by providing an electron injection layer between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide, etc. can be used as cathodes regardless of the size of the work function.

[0339] When the second electrode 102 is formed using a material that transmits visible light, a light-emitting device that emits light from the second electrode 102 side can be formed.

[0340] These conductive materials can be deposited by dry methods such as vacuum deposition and sputtering, inkjet, spin coating, etc. Alternatively, they can be formed by wet methods such as sol-gel or by wet methods using a metal paste.

[0341] The organic compound layer 103 can be formed using various methods, whether dry or wet, such as vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating.

[0342] In addition, the electrodes or layers mentioned above may also be formed by using different deposition methods.

[0343] This embodiment mode can be appropriately combined with other embodiment modes or examples. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be appropriately combined.

[0344] Implementation 3 like Figure 6A and Figure 6B As shown, a plurality of light-emitting devices 130 are formed on an insulating layer 175 to form a display device. In this embodiment, a display device according to one embodiment of the present invention is described in detail.

[0345] The display device 100 includes a pixel portion 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 includes a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0346] In this specification, for example, sub-pixel 110 may be used to describe common features among sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B. Furthermore, for other components distinguished by letters, reference numerals may be used without the letters to describe common features among the components.

[0347] Sub-pixel 110R presents red light, sub-pixel 110G presents green light, and sub-pixel 110B presents blue light. Thus, an image can be displayed on the pixel portion 177. Note that in this embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are used as examples for explanation, and sub-pixels of other colors can also be combined. In addition, the number of sub-pixels is not limited to three, and can be four or more. As four sub-pixels, for example, there can be mentioned: sub-pixels of four colors, R, G, B, and white (W); sub-pixels of four colors, R, G, B, and Y; and sub-pixels of four colors, R, G, B, and infrared light (IR); and the like.

[0348] In this specification and the like, the row direction may be referred to as the X direction and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly intersect.

[0349] exist Figure 6A In the example shown, sub-pixels of different colors are arranged in the X direction, and sub-pixels of the same color are arranged in the Y direction. Note that sub-pixels of different colors may also be arranged in the Y direction, and sub-pixels of the same color may be arranged in the X direction.

[0350] Connecting portion 140 is provided outside pixel portion 177, and region 141 may also be provided. For example, region 141 is provided between pixel portion 177 and connecting portion 140. Organic compound layer 103 is provided in region 141. Connecting portion 140 is provided with conductive layer 151C.

[0351] exist Figure 6A In the example shown, the region 141 and the connection portion 140 are located on the right side of the pixel portion 177. However, there is no particular limitation on the positions of the region 141 and the connection portion 140. Alternatively, there may be one or more regions 141 and the connection portion 140.

[0352] Figure 6B It is along Figure 6A An example of a cross-sectional view along the dotted line A1-A2 in FIG. Figure 6BAs shown, display device 100 includes an insulating layer 171, a conductive layer 172 on insulating layer 171, an insulating layer 173 on insulating layer 171 and conductive layer 172, an insulating layer 174 on insulating layer 173, and an insulating layer 175 on insulating layer 174. Insulating layer 171 is provided on a substrate (not shown). Insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach conductive layer 172, and plugs 176 are provided so as to fit into these openings.

[0353] In pixel portion 177, light-emitting devices 130 are provided on insulating layer 175 and plug 176. Protective layer 131 is provided to cover light-emitting devices 130. Substrate 120 is bonded to protective layer 131 via resin layer 122. Furthermore, inorganic insulating layer 125 and insulating layer 127 on inorganic insulating layer 125 are preferably provided between adjacent light-emitting devices 130.

[0354] Figure 6B Although cross-sections of the plurality of inorganic insulating layers 125 and the plurality of insulating layers 127 are shown, the inorganic insulating layers 125 and 127 are preferably formed as a continuous layer when viewing the display device 100 from above. In other words, the inorganic insulating layers 125 and 127 are preferably insulating layers having openings above the first electrodes.

[0355] Figure 6B Light-emitting devices 130R, 130G, and 130B are shown as light-emitting devices 130. Light-emitting devices 130R, 130G, and 130B emit different colors. For example, light-emitting device 130R may emit red light, light-emitting device 130G may emit green light, and light-emitting device 130B may emit blue light. Light-emitting devices 130R, 130G, and 130B may also emit other visible light or infrared light.

[0356] The display device according to one embodiment of the present invention may have, for example, a top emission structure that emits light in a direction opposite to a substrate on which a light-emitting device is formed. Alternatively, the display device according to one embodiment of the present invention may have a bottom emission structure.

[0357] Examples of the light-emitting substance contained in the light-emitting device 130 include organic compounds or organometallic complexes such as substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescent materials), and substances that exhibit thermally activated delayed fluorescence (TADF materials). Inorganic compounds such as quantum dots may also be used.

[0358] The light-emitting device 130R has the structure described in Embodiment 1, including a first electrode (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer 104. The common layer 104 may or may not be provided, but providing the common layer 104 is preferred because it reduces damage to the organic compound layer 103R during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. Furthermore, when the common layer 104 is provided, the stacked structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 2.

[0359] The light-emitting device 130G has the structure described in Embodiment 1, including a first electrode (pixel electrode) composed of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer 104. The common layer 104 may or may not be provided, but the provision of the common layer 104 is preferred because it reduces damage to the organic compound layer 103G during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. Furthermore, when the common layer 104 is provided, the stacked structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 2.

[0360] The light-emitting device 130B has the structure described in Embodiment 1, including a first electrode (pixel electrode) composed of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer 104. The common layer 104 may or may not be provided, but providing the common layer 104 is preferred because it can reduce damage to the organic compound layer 103B during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. In addition, when the common layer 104 is provided, the stacked structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 2.

[0361] The light emitting device includes a pixel electrode and a common electrode, one of which is used as an anode and the other as a cathode. The following description assumes that the pixel electrode is used as an anode and the common electrode is used as a cathode, unless otherwise specified.

[0362] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are independently formed into an island shape for each sub-pixel or for each luminescent color. By forming the organic compound layer 103 into an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-definition display device. This reduces crosstalk and enables a display device with extremely high contrast. In particular, a display device with high current efficiency can be achieved at low brightness.

[0363] The island-shaped organic compound layer 103 is formed by depositing an EL film and processing the EL film using a photolithography technique.

[0364] In addition, in the display device of one embodiment of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked structure. Figure 6B In the example shown, the first electrode of the light-emitting device 130 has a stacked-layer structure of a conductive layer 151 (conductive layer 151R, conductive layer 151G, conductive layer 151B) and a conductive layer 152 (conductive layer 152R, conductive layer 152G, conductive layer 152B). For example, when the display device 100 has a top emission structure and the pixel electrode of the light-emitting device 130 is used as an anode, it is preferred that the conductive layer 151 is a layer with high visible light reflectivity, and the conductive layer 152 is, for example, a layer with visible light transmittance and a large work function. When the display device 100 has a top emission structure, the higher the visible light reflectivity of the pixel electrode, the higher the light extraction efficiency emitted by the organic compound layer 103 can be. In addition, when the pixel electrode is used as an anode, the greater the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. Thus, since the pixel electrode of the light-emitting device 130 has a stacked structure of the conductive layer 151 with high visible light reflectivity and the conductive layer 152 with large work function, the light-emitting device 130 can be a light-emitting device with high light extraction efficiency and low driving voltage.

[0365] When conductive layer 151 is a layer having a high visible light reflectivity, the visible light reflectivity of conductive layer 151 is preferably, for example, 40% to 100% or 70% to 100%. Furthermore, when conductive layer 152 is an electrode having visible light transmittance, the visible light transmittance is preferably, for example, 40% or more.

[0366] Here, when the pixel electrode has a multi-layer stacked structure, the pixel electrode may be degraded due to reactions between the layers. For example, when a film formed after forming the pixel electrode is removed by wet etching, galvanic corrosion may occur due to contact of the chemical solution with the pixel electrode.

[0367] In view of this, in the display device 100 of this embodiment, the insulating layer 156 is formed so as to cover the side surfaces of the conductive layer 151 and the conductive layer 152. This prevents a chemical solution from contacting the conductive layer 151, for example, even when a film formed after forming the pixel electrode including the conductive layer 151 and the conductive layer 152 is removed using a wet etching method. Thus, for example, galvanic corrosion can be suppressed in the pixel electrode. Consequently, the display device 100 can be manufactured using a method with a high yield, thereby achieving an inexpensive display device. Furthermore, defects in the display device 100 can be suppressed, resulting in a highly reliable display device.

[0368] For example, a metal 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), and neodymium (Nd), as well as alloys obtained by appropriately combining these metals, can be used.

[0369] The conductive layer 152 can be made of an oxide containing one or more selected from the group consisting of indium, tin, zinc, gallium, titanium, aluminum, and silicon. For example, preferably used are conductive oxides containing one or more of 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. Indium tin oxide containing silicon has a particularly large work function, for example, 4.0 eV or greater, and is therefore suitable for use as the conductive layer 152.

[0370] Conductive layer 151 and conductive layer 152 may each have a stacked-layer structure including multiple layers of different materials. In this case, conductive layer 151 may include a layer using a material that can be used for conductive layer 152, such as a conductive oxide, and conductive layer 152 may include a layer using a material that can be used for conductive layer 151, such as a metal material. For example, when conductive layer 151 has a stacked-layer structure of two or more layers, the layer in contact with conductive layer 152 may be a layer using a material that can be used for conductive layer 152.

[0371] Note that the end of the insulating layer 156 may be tapered. Specifically, when the end of the insulating layer 156 is tapered with a taper angle of less than 90°, coverage of structures provided along the side surfaces of the insulating layer 156 can be improved.

[0372] Figure 7A This is a diagram when the conductive layer 151 has a stacked structure of multiple layers containing different materials. Figure 7AAs shown, the conductive layer 151 includes a conductive layer 151a, a conductive layer 151b on the conductive layer 151a, and a conductive layer 151c on the conductive layer 151b. Figure 7A The conductive layer 151 shown has a three-layer stacked structure. In this case, when the conductive layer 151 has a multi-layer stacked structure, at least one of the layers constituting the conductive layer 151 may have a visible light reflectivity higher than that of the conductive layer 152 .

[0373] exist Figure 7A In the example shown, conductive layer 151b is sandwiched between conductive layer 151a and conductive layer 151c. Conductive layer 151a and conductive layer 151c can be made of a material that is less susceptible to degradation than conductive layer 151b. For example, conductive layer 151a can be made of a material that is less susceptible to migration due to contact with insulating layer 175 than conductive layer 151b. Furthermore, conductive layer 151c can be made of a material that is less susceptible to oxidation than conductive layer 151b and whose oxide has a lower resistivity than the oxide of the material used for conductive layer 151b.

[0374] In this manner, by adopting a structure in which conductive layer 151b is sandwiched between conductive layer 151a and conductive layer 151c, the range of materials available for conductive layer 151b can be expanded. Thus, for example, conductive layer 151b can be made to have a higher visible light reflectivity than at least one of conductive layer 151a and conductive layer 151c. For example, aluminum can be used as conductive layer 151b. Alternatively, an alloy containing aluminum can be used as conductive layer 151b. Furthermore, titanium can be used as conductive layer 151a. Although titanium has a lower visible light reflectivity than aluminum, it is less likely to migrate even when in contact with insulating layer 175 than aluminum. Furthermore, titanium can be used as conductive layer 151c. Although titanium has a lower visible light reflectivity than aluminum, it is less susceptible to oxidation than aluminum, and the resistivity of its oxide is lower than that of aluminum oxide.

[0375] In addition, silver or an alloy containing silver can also be used as the conductive layer 151c. Silver has a higher visible light reflectivity than titanium. Furthermore, silver has the following characteristics: it is not easily oxidized compared to aluminum, and the resistivity of silver oxide is lower than the resistivity of aluminum oxide. Therefore, when silver or an alloy containing silver is used as the conductive layer 151c, the visible light reflectivity of the conductive layer 151 can be appropriately improved while suppressing the increase in resistance of the pixel electrode due to oxidation of the conductive layer 151b. Here, as an alloy containing silver, for example, an alloy of silver, palladium and copper (Ag-Pd-Cu, also referred to as APC) can be used. In addition, when silver or an alloy containing silver is used as the conductive layer 151c and aluminum is used as the conductive layer 151b, the visible light reflectivity of the conductive layer 151c can be increased compared to the visible light reflectivity of the conductive layer 151b. Here, silver or an alloy containing silver can also be used as the conductive layer 151b. In addition, silver or an alloy containing silver can also be used as the conductive layer 151a.

[0376] On the other hand, a film made of titanium has better etching processability than a film made of silver. Therefore, by using titanium as the conductive layer 151c, the conductive layer 151c can be easily formed. In addition, a film made of aluminum also has better etching processability than a film made of silver.

[0377] By making the conductive layer 151 have a stacked structure of multiple layers, the characteristics of the display device can be improved. For example, the display device 100 can have high light extraction efficiency and high reliability.

[0378] Here, when the light emitting device 130 adopts a microcavity structure, by using silver or an alloy containing silver, which is a material with high visible light reflectivity, as the conductive layer 151 c , the light extraction efficiency of the display device 100 can be appropriately improved.

[0379] As described above, the side surface of the conductive layer 151 preferably has a tapered shape. Specifically, the side surface of the conductive layer 151 preferably has a tapered shape with a taper angle less than 90°. Figure 7A In the conductive layer 151 having the structure shown, it is preferable that a side surface of at least one of the conductive layer 151 a , the conductive layer 151 b , and the conductive layer 151 c has a tapered shape.

[0380] Figure 7AThe conductive layer 151 shown can be formed by lithography. Specifically, first, a conductive film to become the conductive layer 151a, a conductive film to become the conductive layer 151b, and a conductive film to become the conductive layer 151c are deposited in sequence. Next, a resist mask is formed on the conductive film to become the conductive layer 151c. Then, the conductive film in the area that does not overlap with the resist mask is removed, for example, by etching. Here, by processing the conductive film under conditions in which the resist mask is more likely to retreat (shrink) than in the case where the conductive layer 151 is formed in a manner that the side does not have a tapered shape (i.e., the side is vertical), a conductive layer 151 having a tapered side can be formed.

[0381] Here, when the conductive film is processed under conditions that allow the resist mask to easily retreat (shrink), the conductive film may be easily processed in the horizontal direction. In other words, the etching isotropy may be higher than when the conductive layer 151 is formed with vertical side surfaces.

[0382] When the conductive layer 151 has a stacked structure of multiple layers made of different materials, the multiple layers may have different eases of processing in the horizontal direction. For example, the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c may have different eases of processing in the horizontal direction.

[0383] In this case, sometimes after processing the conductive film, Figure 7A As shown, the side surface of conductive layer 151b is located inside the side surfaces of conductive layer 151a and conductive layer 151c to form a protrusion. This may reduce the coverage of conductive layer 152 with conductive layer 151 and cause disconnection of conductive layer 152.

[0384] In view of this, it is preferred to Figure 7A Insulating layer 156 is provided in this manner. Figure 7A Insulating layer 156 is provided on conductive layer 151a to have a region overlapping with the side surface of conductive layer 151b. This prevents disconnection or thinning of conductive layer 152 due to the protrusion, thereby preventing connection failure and increase in driving voltage.

[0385] Note that although Figure 7A Although the structure in which the entire side surface of the conductive layer 151b is covered by the insulating layer 156 is shown, a portion of the side surface of the conductive layer 151b may not be covered by the insulating layer 156. Similarly, in the pixel electrode having the structure shown below, a portion of the side surface of the conductive layer 151b may not be covered by the insulating layer 156.

[0386] The conductive layer 151 has Figure 7AIn the structure shown, conductive layer 152 covers conductive layer 151a, conductive layer 151b, conductive layer 151c, and insulating layer 156 and is electrically connected to conductive layer 151a, conductive layer 151b, and conductive layer 151c. Thus, even when removing a film deposited after forming conductive layer 152 by wet etching, for example, a chemical solution does not contact conductive layer 151a, conductive layer 151b, and conductive layer 151c. Consequently, corrosion in conductive layer 151a, conductive layer 151b, and conductive layer 151c can be suppressed. Consequently, display device 100 can be manufactured using a method with a high yield. Furthermore, defects can be suppressed, thereby achieving a highly reliable display device 100.

[0387] Here, if Figure 7A As shown, the insulating layer 156 preferably has a curved surface. Thus, for example, compared to a case where the side surface of the insulating layer 156 is perpendicular (parallel to the Z direction), the occurrence of disconnection in the conductive layer 152 covering the insulating layer 156 can be suppressed. Furthermore, when the side surface of the insulating layer 156 has a tapered shape, specifically a tapered shape with a taper angle of less than 90°, for example, compared to a case where the side surface of the insulating layer 156 is perpendicular, the occurrence of disconnection in the conductive layer 152 covering the insulating layer 156 can be suppressed. Thus, the display device 100 can be manufactured using a method with a high yield. Furthermore, the occurrence of defects is suppressed, and the display device 100 can be made into a highly reliable display device.

[0388] Notice, Figure 7A Although the side surfaces of conductive layer 151b are shown as being located inside the side surfaces of conductive layer 151a and conductive layer 151c, one embodiment of the present invention is not limited thereto. For example, the side surfaces of conductive layer 151b may be located outside the side surfaces of conductive layer 151a. Alternatively, the side surfaces of conductive layer 151b may be located outside the side surfaces of conductive layer 151c.

[0389] Figures 7B to 7D Other structures of the first electrode 101 are shown. Figure 7B Shown in Figure 7A In the first electrode 101, the insulating layer 156 covers the side surfaces of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c in addition to the side surfaces of the conductive layer 151b.

[0390] Figure 7C Shown in Figure 7A The insulating layer 156 is not provided in the first electrode 101.

[0391] Figure 7D The following structure is shown: Figure 7A In the first electrode 101, the conductive layer 151 does not have a stacked-layer structure and the conductive layer 152 has a stacked-layer structure.

[0392] Conductive layer 152a has higher adhesion to conductive layer 152b than, for example, insulating layer 175. For example, conductive layer 152a can be made of an oxide containing one or more selected from the group consisting of indium, tin, zinc, gallium, titanium, aluminum, and silicon. For example, preferably, conductive oxides containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium titanium oxide, zinc titanate, aluminum zinc oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon are used. This can suppress film peeling of conductive layer 152b. Furthermore, conductive layer 152b can be prevented from contacting insulating layer 175.

[0393] The conductive layer 152b is a layer having a higher visible light reflectivity (for example, reflectivity for light of a specified wavelength within a range of greater than 400 nm and less than 750 nm) than the conductive layer 151, the conductive layer 152a, and the conductive layer 152c. The visible light reflectivity of the conductive layer 152b can be, for example, greater than 70% and less than 100%, preferably greater than 80% and less than 100%, and more preferably greater than 90% and less than 100%. In addition, as the conductive layer 152b, for example, a material having a higher visible light reflectivity than aluminum can be used. Specifically, for example, silver or an alloy containing silver can be used as the conductive layer 152b. As an example of an alloy containing silver, an alloy of silver, palladium, and copper (APC) can be cited. As a result, the display device 100 can be made into a display device with high light extraction efficiency. Note that a metal other than silver can also be used as the conductive layer 152b.

[0394] When the conductive layers 151 and 152 are used as anodes, the conductive layer 152c is preferably a layer having a large work function. For example, the conductive layer 152c has a larger work function than the conductive layer 152b. For example, the conductive layer 152c can use the same material as that used for the conductive layer 152a. For example, the same material can be used for both the conductive layer 152a and the conductive layer 152c. For example, when indium tin oxide is used for the conductive layer 152a, it can also be used for the conductive layer 152c.

[0395] Note that when the conductive layer 151 and the conductive layer 152 are used as a cathode, the conductive layer 152c is preferably a layer with a small work function. For example, the conductive layer 152c is a layer with a smaller work function than the conductive layer 152b.

[0396] In addition, the conductive layer 152c is preferably a layer with high visible light transmittance (for example, transmittance to light of a specified wavelength in the range of 400 nm to less than 750 nm). For example, the visible light transmittance of the conductive layer 152c is preferably higher than the visible light transmittance of the conductive layer 151 and the conductive layer 152b. For example, the visible light transmittance of the conductive layer 152c can be greater than 60% and less than 100%, preferably greater than 70% and less than 100%, and more preferably greater than 80% and less than 100%. As a result, the light emitted by the organic compound layer 103 and absorbed by the conductive layer 152c can be reduced. In addition, as described above, the conductive layer 152b below the conductive layer 152c can be a layer with high visible light reflectivity. Therefore, the display device 100 can be a display device with high light extraction efficiency.

[0397] Next, refer to 8A to 13C Description Figure 6A An example of a method for manufacturing a display device 100 having the structure shown. The organic compound layer of the light-emitting device included in the display device 100 is formed through a manufacturing process that includes a water treatment. By using the organic compound of one embodiment of the present invention in the organic layer of the light-emitting device included in the display device of one embodiment of the present invention, even when manufactured using a manufacturing process that includes a water treatment, problems such as dissolution of the layer including the organic compound and penetration of chemical solutions into the layer using the organic compound can be prevented, thereby providing a light-emitting device with excellent characteristics.

[0398] [Manufacturing method example] Thin films (insulating films, semiconductor films, conductive films, etc.) that constitute display devices can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and ALD. CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. Another thermal CVD method is metal organic chemical vapor deposition (MOCVD).

[0399] In addition, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using wet deposition methods such as spin coating, dipping, spraying, inkjet, dispenser, screen printing, offset printing, doctor knife, slit coating, roller coating, curtain coating or doctor knife coating.

[0400] In particular, when manufacturing a light-emitting device, a vacuum process such as an evaporation method and a solution process such as a spin coating method and an inkjet method can be utilized. As an evaporation method, physical evaporation methods (PVD methods) such as sputtering, ion plating, ion beam evaporation, molecular beam evaporation, and vacuum evaporation methods and chemical vapor deposition methods (CVD methods) can be cited. In particular, the functional layer (hole injection layer, hole transport layer, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer and electron injection layer, etc.) included in the organic compound layer can be formed using evaporation methods (vacuum evaporation methods, etc.), coating methods (dip coating methods, dye coating methods, rod coating methods, spin coating methods, spray coating methods), printing methods (inkjet methods, screen printing (porcelain printing) methods, offset printing (lithography) methods, flexographic printing (letterpress printing) methods, gravure printing methods or micro-contact printing methods, etc.) and other methods.

[0401] Furthermore, when processing thin films constituting a display device, for example, lithography can be used. Alternatively, thin films can be processed using nanoimprinting, sandblasting, lift-off, or the like. Furthermore, island-shaped thin films can be directly formed using a deposition method using a shadow mask such as a metal mask.

[0402] As a lithography technique, for example, photolithography can be used. There are two typical photolithography methods. One involves forming a resist mask on a thin film to be processed, processing the film by, for example, etching, and then removing the resist mask. The other involves forming a photosensitive thin film, then exposing and developing the film to the desired shape.

[0403] In the photolithography method, as the light used for exposure, for example, i-line (wavelength of 365nm), g-line (wavelength of 436nm), h-line (wavelength of 405nm) or light obtained by mixing these lights can be used. In addition, ultraviolet light, KrF laser or ArF laser, etc. can also be used. In addition, exposure can also be performed using liquid immersion exposure technology. In addition, as the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays can also be used. In addition, instead of the light used for exposure, an electron beam can also be used. When extreme ultraviolet light, X-rays or electron beams are used, extremely fine processing can be performed, so it is preferred. In addition, when exposure is performed by scanning a light beam such as an electron beam, a photomask is not required.

[0404] For etching of the thin film, dry etching, wet etching, sand blasting, or the like can be used.

[0405] First, if Figure 8AAs shown, an insulating layer 171 is formed on a substrate (not shown). Next, conductive layers 172 and 179 are formed on insulating layer 171, and insulating layer 173 is formed on insulating layer 171 to cover conductive layers 172 and 179. Next, insulating layer 174 is formed on insulating layer 173, and insulating layer 175 is formed on insulating layer 174.

[0406] As the substrate, a substrate having heat resistance at least sufficient to withstand the subsequent heat treatment can be used. When an insulating substrate is used as the substrate, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, or an organic resin substrate can be used. Alternatively, a semiconductor substrate such as a single crystal semiconductor substrate or a polycrystalline semiconductor substrate made of silicon or silicon carbide, a compound semiconductor substrate made of silicon germanium, or an SOI substrate can be used.

[0407] Then, if Figure 8A As shown in FIG. 1 , openings reaching the conductive layer 172 are formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Next, the plug 176 is formed so as to fit into the opening.

[0408] Then, if Figure 8A As shown, a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, is formed on the plug 176 and the insulating layer 175. The conductive film 151f can be formed by, for example, sputtering or vacuum deposition. A metal material can be used as the conductive film 151f.

[0409] Then, if Figure 8A As shown, a conductive film 152f, which will later become the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C, is formed on the conductive film 151f. The conductive film 152f can be formed, for example, by sputtering or vacuum evaporation. Alternatively, a conductive oxide can be used as the conductive film 152f. Alternatively, the conductive film 152f can have a stacked structure comprising a film made of a metal material and a film made of a conductive oxide on top of the film. For example, the conductive film 152f can have a stacked structure comprising a film made of titanium, silver, or an alloy containing silver and a film made of a conductive oxide on top of the film.

[0410] In addition, the conductive film 152f can be formed using the ALD method. Here, as the conductive film 152f, an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum and silicon can be used. At this time, by introducing a precursor (generally sometimes referred to as a precursor or metal precursor, etc.), purging the precursor, introducing an oxidant (generally sometimes referred to as a reactant, reactant or non-metallic precursor, etc.) and purging the oxidant as one cycle, the conductive film 152f can be formed by repeating the cycle. Here, when an oxide film containing multiple metals such as indium tin oxide is formed as the conductive film 152f, the metal composition can be controlled by changing the number of cycles according to the type of precursor.

[0411] For example, when depositing an indium tin oxide film as the conductive film 152f, an indium-containing precursor is introduced, the precursor is purged, and an oxidant is introduced to form an In-O film. Subsequently, a tin-containing precursor is introduced, the precursor is purged, and an oxidant is introduced to form a Sn-O film. By making the number of cycles for forming the In-O film greater than the number of cycles for forming the Sn-O film, the number of In atoms contained in the conductive film 152f can be made greater than the number of Sn atoms.

[0412] Furthermore, for example, when a zinc oxide film is deposited as the conductive film 152f, a Zn-O film is formed through the above-described process. Furthermore, for example, when an aluminum zinc oxide film is deposited as the conductive film 152f, a Zn-O film and an Al-O film are formed through the above-described process. Furthermore, for example, when a titanium oxide film is deposited as the conductive film 152f, a Ti-O film is formed through the above-described process. Furthermore, for example, when an indium tin oxide film containing silicon is deposited as the conductive film 152f, an In-O film, a Sn-O film, and a Si-O film are formed through the above-described process. Furthermore, for example, when a zinc oxide film containing gallium is deposited, a Ga-O film and a Zn-O film are formed through the above-described process.

[0413] As a precursor containing indium, for example, triethylindium, trimethylindium or [1,1,1-trimethyl-N-(trimethylsilyl)amide]-indium can be used. As a precursor containing tin, for example, tin chloride or tetrakis(dimethylamide)tin can be used. As a precursor containing zinc, for example, diethylzinc or dimethylzinc can be used. As a precursor containing gallium, for example, triethylgallium can be used. As a precursor containing titanium, for example, titanium chloride, tetrakis(dimethylamide)titanium or tetraisopropyl titanate can be used. As a precursor containing aluminum, for example, aluminum chloride or trimethylaluminum can be used. As a precursor containing silicon, for example, trisilylamine, bis(diethylamino)silane, tris(dimethylamino)silane, bis(tert-butylamino)silane or bis(ethylmethylamino)silane can be used. In addition, as an oxidant, water vapor, oxygen plasma or ozone gas can be used.

[0414] Then, if Figure 8A As shown in FIG. 1 , a resist mask 191 is formed on the conductive film 151f and the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist), exposing the material to light, and developing the material.

[0415] Then, if Figure 8B As shown, the conductive film 151f and the conductive film 152f in the region not overlapping with the resist mask 191 are removed by etching, specifically, dry etching, to form a pixel electrode including the conductive layer 151 and the conductive layer 152. Note that if the conductive film 151f includes a layer made of a conductive oxide such as indium tin oxide, this layer can also be removed by wet etching. Thus, the conductive layers 151 and 152 are formed. Note that, for example, when a portion of the conductive film 151f is removed by dry etching, a recessed portion may be formed in the region of the insulating layer 175 that does not overlap with the conductive layer 151.

[0416] Note that after the conductive film 152f is processed using lithography to form the conductive layers 152R, 152G, 152B, and 152C, the conductive film 151f may be processed using the conductive layers 152R, 152G, 152B, and 152C as masks. Specifically, for example, after forming a resist mask, a portion of the conductive film 152f may be removed using etching. For example, the conductive film 152f may be removed using wet etching. Note that dry etching may also be used to remove the conductive film 152f. Subsequently, the conductive film 151f is preferably removed using wet etching.

[0417] Here, it is preferable to perform a hydrophobic treatment on the conductive layer 152. The hydrophobic treatment can change the surface state of the treatment object from hydrophilic to hydrophobic, or can improve the hydrophobicity of the surface of the treatment object. The hydrophobic treatment of the conductive layer 152 can improve the adhesion between the conductive layer 152 and the organic compound layer 103 to be formed in a subsequent step, thereby suppressing film peeling. Note that the hydrophobic treatment can also be omitted.

[0418] Then, if Figure 8C As shown, the resist mask 191 is removed. The resist mask 191 can be removed by, for example, ashing using oxygen plasma. Alternatively, oxygen gas and CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or a Group 18 element such as He can be used. Alternatively, the resist mask 191 can be removed by wet etching.

[0419] Then, then, as Figure 8DAs shown, an insulating film 156f, which will later become insulating layers 156R, 156G, 156B, and 156C, is formed on conductive layers 151R and 152R, conductive layers 151G and 152G, conductive layers 151B and 152B, conductive layers 151C and 152C, and insulating layer 175. Insulating film 156f can be formed by, for example, CVD, ALD, sputtering, or vacuum evaporation.

[0420] The insulating film 156f can be made of an inorganic material. For example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film can be used as the insulating film 156f. For example, an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film containing silicon can be used as the insulating film 156f. For example, silicon oxynitride can be used as the insulating film 156f.

[0421] Then, if Figure 8E As shown, insulating film 156f is processed to form insulating layer 156R, insulating layer 156G, insulating layer 156B, and insulating layer 156C. For example, insulating layer 156 can be formed by etching the top surface of insulating film 156f substantially uniformly. This process of planarizing by uniform etching is also called etch-back. Alternatively, insulating layer 156 can be formed using lithography.

[0422] Then, if Figure 9A As shown in FIG. 1 , an organic compound film 103Rf, which will later become the organic compound layer 103R, is formed over the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, and the insulating layer 175 .

[0423] like Figure 9A As shown, the organic compound film 103Rf is not formed on the conductive layer 152C. For example, by using a mask for defining the deposition range (also referred to as an area mask or a rough metal mask to distinguish it from a high-definition metal mask), the organic compound film 103Rf can be deposited only in the desired area. By adopting a deposition process using an area mask and a processing process using a resist mask, a light-emitting device can be manufactured using a relatively simple process.

[0424] The organic compound film 103Rf can be formed by, for example, vapor deposition, specifically, vacuum deposition, or by transfer, printing, inkjet, coating, or other methods.

[0425] Then, if Figure 9AAs shown, a sacrificial film 158Rf, which will later become a sacrificial layer 158R, and a mask film 159Rf, which will later become a mask layer 159R, are formed in this order on the organic compound film 103Rf, the conductive layer 152C, and the insulating layer 175 .

[0426] Note that in this embodiment, an example is shown in which the mask film has a two-layer structure of the sacrificial film 158Rf and the mask film 159Rf. However, the mask film may have a single-layer structure or a stacked-layer structure of three or more layers.

[0427] By providing a sacrificial layer on the organic compound film 103Rf, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0428] The sacrificial film 158Rf is a film having high resistance to the processing conditions of the organic compound film 103Rf, specifically, a film having a large etching selectivity with the organic compound film 103Rf. The mask film 159Rf is a film having a large etching selectivity with the sacrificial film 158Rf.

[0429] 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 during formation of the sacrificial film 158Rf and the sacrificial film 159Rf is typically 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, further preferably 100°C or lower, and even more preferably 80°C or lower.

[0430] The sacrificial film 158Rf and the mask film 159Rf are preferably films that can be removed by wet etching. Wet etching can reduce damage to the organic compound film 103Rf during processing of the sacrificial film 158Rf and the mask film 159Rf compared to dry etching.

[0431] The sacrificial film 158Rf and the mask film 159Rf can be formed by, for example, sputtering, ALD (thermal ALD, PEALD), CVD, or vacuum deposition, or by the aforementioned wet deposition method.

[0432] The sacrificial film 158Rf formed in contact with the organic compound film 103Rf is preferably formed by a formation method that causes less damage to the organic compound film 103Rf than when forming the mask film 159Rf. For example, the sacrificial film 158Rf is preferably formed by ALD or vacuum evaporation rather than sputtering.

[0433] As the sacrificial film 158Rf and the mask film 159Rf, for example, one or more of a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, and an inorganic insulating film can be used.

[0434] For example, the sacrificial film 158Rf and the mask film 159Rf can each be made of a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy containing such a metal material. Low-melting-point materials such as aluminum or silver are particularly preferred. Using a metal material that blocks ultraviolet light for one or both of the sacrificial film 158Rf and the mask film 159Rf is preferred because it can prevent ultraviolet light from reaching the organic compound film 103Rf and thus suppress degradation of the organic compound film 103Rf.

[0435] In addition, as the sacrificial film 158Rf and the mask film 159Rf, metal oxides 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 indium tin oxide containing silicon can be used respectively.

[0436] Note that element M (M is one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used instead of gallium.

[0437] Furthermore, the sacrificial film and the mask film are preferably made of a material having light-shielding properties, particularly ultraviolet light-shielding properties. The light-shielding material can include various materials such as metals, insulators, semiconductors, and semimetals that have ultraviolet light-shielding properties. Since part or all of the sacrificial film and the mask film will be removed in a subsequent step, the sacrificial film and the mask film are preferably films that can be processed by etching, and particularly preferably films with good processability.

[0438] When semiconductor materials such as silicon or germanium are used as sacrificial films and mask films, they are preferred because they have a high affinity with the semiconductor manufacturing process. Alternatively, oxides or nitrides of the above-mentioned semiconductor materials can be used. Alternatively, non-metallic materials such as carbon or their compounds can be used. In addition, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or alloys containing one or more of these, can be used. In addition, oxides containing the above-mentioned metals, such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0439] Furthermore, by using a film made of a material with UV-shielding properties as a sacrificial film or mask film, it is possible to prevent UV rays from reaching the organic compound layer during, for example, the exposure process. This prevents UV rays from damaging the organic compound layer, thereby improving the reliability of the light-emitting device.

[0440] Note that a film containing a material having ultraviolet light-shielding properties also produces the same effect when used as a material for the inorganic insulating film 125f described later.

[0441] In addition, various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf. In particular, an oxide insulating film is preferred because it has higher adhesion to the organic compound film 103Rf than a nitride insulating film. For example, an inorganic insulating material such as aluminum oxide, hafnium oxide, or silicon oxide can be used for the sacrificial film 158Rf and the mask film 159Rf. For example, an aluminum oxide film can be formed as the sacrificial film 158Rf and the mask film 159Rf using the ALD method. By using the ALD method, damage to the substrate (especially the organic compound layer) can be reduced, which is preferred.

[0442] For example, an inorganic insulating film (e.g., an aluminum oxide film) formed using an ALD method can be used as the sacrificial film 158Rf, and an inorganic film (e.g., an In-Ga-Zn oxide film, an aluminum film, or a tungsten film) formed using a sputtering method can be used as the mask film 159Rf.

[0443] In addition, the same inorganic insulating film can be used for both the sacrificial layer 158Rf and the inorganic insulating layer 125 to be formed later. For example, an aluminum oxide film formed using the ALD method can be used for both the sacrificial layer 158Rf and the inorganic insulating layer 125. Here, the sacrificial layer 158Rf and the inorganic insulating layer 125 can be deposited under the same deposition conditions or different deposition conditions. For example, by depositing the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, the sacrificial film 158Rf can be formed as an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, the sacrificial film 158Rf is a layer that will be mostly or entirely removed in a subsequent step, so it is preferably easy to process. Therefore, the sacrificial layer 158Rf is preferably deposited under conditions where the substrate temperature is lower than that of the inorganic insulating layer 125 during deposition.

[0444] Organic materials may be used for either or both of the sacrificial film 158Rf and the mask film 159Rf. For example, the organic material may be soluble in a solvent that is chemically stable to at least the film located on the uppermost portion of the organic compound film 103Rf. In particular, materials that are soluble in water or alcohol are suitable. When depositing these materials, it is preferred to apply the material by a wet deposition method while dissolving it in a solvent such as water or alcohol, followed by a heat treatment to evaporate the solvent. In this case, the heat treatment is preferably performed in a reduced pressure atmosphere, as this allows the solvent to be removed at a low temperature and in a short time, thereby minimizing thermal damage to the organic compound film 103Rf.

[0445] The sacrificial film 158Rf and the mask film 159Rf may each be made of an organic resin such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin, or fluororesin such as perfluoropolymer.

[0446] For example, an organic film (eg, a PVA film) formed using any of the evaporation method and the above-described wet deposition method may be used as the sacrificial film 158Rf, and an inorganic film (eg, a silicon nitride film) formed using a sputtering method may be used as the mask film 159Rf.

[0447] Then, if Figure 9A As shown in FIG. 1 , a resist mask 190R is formed on the mask film 159Rf. The resist mask 190R can be formed by applying a photosensitive material (photoresist), exposing it to light, and developing it.

[0448] The resist mask 190R may use a positive resist material or a negative resist material.

[0449] The resist mask 190R is provided at a position overlapping with the conductive layer 152R. The resist mask 190R is preferably also provided at a position overlapping with the conductive layer 152C. This can prevent the conductive layer 152C from being damaged during the manufacturing process of the display device. Note that the resist mask 190R may not be provided on the conductive layer 152C. Figure 9A As shown in the cross-sectional view taken along B1 - B2 in FIG, the resist mask 190R is preferably provided so as to cover the end portion of the organic compound film 103Rf to the end portion of the conductive layer 152C (the end portion on the organic compound film 103Rf side).

[0450] Then, if Figure 9BAs shown, a portion of mask film 159Rf is removed using resist mask 190R to form mask layer 159R. Mask layer 159R remains on conductive layer 152R and conductive layer 152C. Resist mask 190R is then removed. Next, mask layer 159R is used as a mask (also referred to as a hard mask) to remove a portion of sacrificial film 158Rf to form sacrificial layer 158R.

[0451] The sacrificial film 158Rf and the mask film 159Rf can be processed by wet etching or dry etching, respectively. The sacrificial film 158Rf and the mask film 159Rf are preferably processed by isotropic etching.

[0452] 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 the case of using the dry etching method. When using the wet etching method, for example, a developer, a tetramethylammonium hydroxide (TMAH) aqueous solution, dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed solution thereof is preferably used.

[0453] Since the organic compound film 103Rf is not exposed when processing the mask film 159Rf, a wider range of processing methods can be selected compared to processing the sacrificial film 158Rf. Specifically, when processing the mask film 159Rf, even when using an oxygen-containing gas as an etching gas, degradation of the organic compound film 103Rf can be suppressed.

[0454] Furthermore, when dry etching is used to process the sacrificial film 158Rf, degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas. When dry etching is used, for example, a gas containing CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or a Group 18 element such as He is preferably used as the etching gas.

[0455] For example, when an aluminum oxide film formed by ALD is used as the sacrificial film 158Rf, a portion of the sacrificial film 158Rf can be removed by dry etching using CHF3 and He, or CHF3, He, and CH4. Furthermore, when an In-Ga-Zn oxide film formed by sputtering is used as the mask film 159Rf, a portion of the mask film 159Rf can be removed by wet etching using dilute phosphoric acid. Alternatively, a portion of the mask film 159Rf can be removed by dry etching using CH4 and Ar. Alternatively, a portion of the mask film 159Rf can be removed by wet etching using dilute phosphoric acid. Furthermore, when a tungsten film formed by sputtering is used as the mask film 159Rf, a portion of the mask film 159Rf can be removed by dry etching using SF6, CF4, and O2, or CF4, Cl2, and O2.

[0456] The resist mask 190R can be removed using the same method as the resist mask 191. For example, the resist mask 190R can be removed by ashing using oxygen plasma. Alternatively, oxygen gas and CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or a Group 18 element such as He can be used. Alternatively, the resist mask 190R can be removed by wet etching. In this case, the sacrificial film 158Rf is located at the outermost surface and the organic compound film 103Rf is not exposed. Therefore, damage to the organic compound film 103Rf can be suppressed during the removal process of the resist mask 190R. In addition, the range of options for removing the resist mask 190R can be expanded.

[0457] Then, if Figure 9B As shown, the organic compound film 103Rf is processed to form the organic compound layer 103R. For example, the organic compound layer 103R is formed by removing a portion of the organic compound film 103Rf using the mask layer 159R and the sacrificial layer 158R as a hard mask.

[0458] Therefore, if Figure 9B As shown, the stacked structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. In addition, the conductive layer 152G and the conductive layer 152B are exposed.

[0459] Figure 9B The example in which the end of the organic compound layer 103R is located outside the end of the conductive layer 152R is shown. By adopting this structure, the pixel can be miniaturized, and a high-definition display can be manufactured. Figure 9B Although not shown in the figure, a recessed portion may be formed in a region of the insulating layer 175 that does not overlap with the organic compound layer 103R due to the etching process described above.

[0460] As described above, the resist mask 190R is preferably provided so as to cover from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side) between B1 and B2. Figure 9B As shown, the sacrificial layer 158R and the mask layer 159R are provided between the dotted line B1-B2 to cover the end of the organic compound layer 103R and the end of the conductive layer 152C (the end on the organic compound layer 103R side). Therefore, for example, exposure of the insulating layer 175 between B1 and B2 can be suppressed. Thus, the insulating layer 175, the insulating layer 174, and a portion of the insulating layer 173 can be suppressed from being removed by etching or the like, thereby exposing the conductive layer 179. Consequently, unintentional electrical connection of the conductive layer 179 to other conductive layers can be suppressed. For example, a short circuit between the conductive layer 179 and the common electrode 155 to be formed in a later step can be suppressed.

[0461] The organic compound film 103Rf is preferably processed by anisotropic etching. Anisotropic dry etching is particularly preferred. Alternatively, wet etching may be used.

[0462] When the dry etching method is used, by not using an oxygen-containing gas as the etching gas, degradation of the organic compound film 103Rf can be suppressed.

[0463] Alternatively, an oxygen-containing gas can be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed at low power while maintaining a sufficient etching rate. This reduces damage to the organic compound film 103Rf and prevents defects such as adhesion of reaction products produced during etching.

[0464] When using a dry etching method, for example, it is preferred to use a gas containing H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3 and one or more of the 18th group elements such as He or Ar as the etching gas. Alternatively, it is preferred to use a gas containing one or more of the above gases and oxygen as the etching gas. Alternatively, oxygen gas can also be used as the etching gas. Specifically, for example, a gas containing H2 and Ar or a gas containing CF4 and He can be used as the etching gas. In addition, for example, a gas containing CF4, He and oxygen can be used as the etching gas. In addition, for example, a gas containing H2 and Ar and an oxygen-containing gas can be used as the etching gas.

[0465] As described above, in one embodiment of the present invention, the mask layer 159R is formed by forming a resist mask 190R on the mask film 159Rf and removing a portion of the mask film 159Rf using the resist mask 190R. Subsequently, the organic compound layer 103R is formed by removing a portion of the organic compound film 103Rf using the mask layer 159R as a mask. Therefore, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using lithography. Alternatively, a portion of the organic compound film 103Rf may be removed using the resist mask 190R. Subsequently, the resist mask 190R may also be removed.

[0466] Next, for example, the conductive layer 152G is preferably subjected to a hydrophobic treatment. When processing the organic compound film 103Rf, for example, the surface of the conductive layer 152G may become hydrophilic. By performing a hydrophobic treatment on the conductive layer 152G, for example, the adhesion between the conductive layer 152G and a layer to be formed in a subsequent step (here, the organic compound layer 103G) can be improved, thereby suppressing film peeling. Note that the hydrophobic treatment may not be performed.

[0467] Then, if Figure 10AAs shown, an organic compound film 103Gf, which will later become the organic compound layer 103G, is formed over the conductive layer 152G, the conductive layer 152B, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159R, and the insulating layer 175.

[0468] 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 that of the organic compound film 103Rf.

[0469] Then, if Figure 10A As shown, a sacrificial film 158Gf, which will later become the sacrificial layer 158G, and a mask film 159Gf, which will later become the mask layer 159G, are sequentially formed on the organic compound film 103Gf and the mask layer 159R. Then, a resist mask 190G is formed. The materials and formation methods of the sacrificial film 158Gf and the mask film 159Gf are the same as those that can be used for the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the resist mask 190G are the same as those that can be used for the resist mask 190R.

[0470] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0471] Then, if Figure 10B As shown, a portion of the mask film 159Gf is removed using a resist mask 190G to form a mask layer 159G. Mask layer 159G remains on the conductive layer 152G. Then, resist mask 190G is removed. Next, mask layer 159G is used as a mask to remove a portion of the sacrificial film 158Gf to form sacrificial layer 158G. Next, the organic compound film 103Gf is processed to form an organic compound layer 103G. For example, mask layer 159G and sacrificial layer 158G are used as hard masks to remove a portion of the organic compound film 103Gf to form an organic compound layer 103G.

[0472] Therefore, if Figure 10B As shown, the stacked structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G. In addition, the mask layer 159R and the conductive layer 152B are exposed.

[0473] Next, for example, the conductive layer 152B is preferably subjected to a hydrophobic treatment. When processing the organic compound film 103Gf, for example, the surface state of the conductive layer 152B may become hydrophilic. By performing a hydrophobic treatment on the conductive layer 152B, for example, the adhesion between the conductive layer 152B and a layer to be formed in a subsequent step (here, the organic compound layer 103B) can be improved, thereby suppressing film peeling. Note that the hydrophobic treatment is not necessarily required.

[0474] Then, if Figure 10C As shown, an organic compound film 103Bf, which will later become the organic compound layer 103B, is formed over the conductive layer 152B, the mask layer 159R, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159G, and the insulating layer 175.

[0475] 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 structure as that of the organic compound film 103Rf.

[0476] Then, if Figure 10C As shown, a sacrificial film 158Bf, which will later become the sacrificial layer 158B, and a mask film 159Bf, which will later become the mask layer 159B, are sequentially formed on the organic compound film 103Bf and the mask layer 159R. Then, a resist mask 190B is formed. The materials and formation methods of the sacrificial film 158Bf and the mask film 159Bf are the same as those that can be used for the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the resist mask 190B are the same as those that can be used for the resist mask 190R.

[0477] The resist mask 190B is provided at a position overlapping with the conductive layer 152B.

[0478] Then, if Figure 10D As shown, a portion of mask film 159Bf is removed using resist mask 190B to form mask layer 159B. Mask layer 159B remains on conductive layer 152B. Resist mask 190B is then removed. Mask layer 159B is then used as a mask to remove a portion of sacrificial film 158Bf to form sacrificial layer 158B. Next, organic compound film 103Bf is processed to form organic compound layer 103B. For example, mask layer 159B and sacrificial layer 158B are used as hard masks to remove a portion of organic compound film 103Bf to form organic compound layer 103B.

[0479] Therefore, if Figure 10D As shown, the stacked 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 layer 159R and the mask layer 159G are exposed.

[0480] Note that the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are preferably perpendicular or substantially perpendicular to the surface on which they are formed. For example, the angle formed between the surface on which they are formed and these side surfaces is preferably not less than 60 degrees and not more than 90 degrees.

[0481] As described above, the distance between two adjacent organic compound layers among the organic compound layers 103R, 103G, and 103B formed using lithography can be reduced to less than 8 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. Here, for example, the distance can be specified based on the distance between the opposing ends of two adjacent organic compound layers among the organic compound layers 103R, 103G, and 103B. In this way, by reducing the distance between the island-shaped organic compound layers, a display device with high definition and a large aperture ratio can be provided. Furthermore, the distance between the first electrodes of adjacent light-emitting devices can be reduced, for example, to less than 10 μm, less than 8 μm, less than 5 μm, less than 3 μm, or less than 2 μm. Furthermore, the distance between the first electrodes of adjacent light-emitting devices is preferably greater than 2 μm and less than 5 μm.

[0482] Then, if Figure 11A As shown, mask layer 159R, mask layer 159G, and mask layer 159B are preferably removed. Depending on the subsequent process, sacrificial layer 158R, sacrificial layer 158G, sacrificial layer 158B, mask layer 159R, mask layer 159G, and mask layer 159B may remain in the display device. By removing mask layer 159R, mask layer 159G, and mask layer 159B at this stage, it is possible to prevent mask layer 159R, mask layer 159G, and mask layer 159B from remaining in the display device. For example, when a conductive material is used for mask layer 159R, mask layer 159G, and mask layer 159B, by removing mask layer 159R, mask layer 159G, and mask layer 159B in advance, it is possible to prevent leakage current and capacitance formation caused by remaining mask layer 159R, mask layer 159G, and mask layer 159B.

[0483] Note that although this embodiment describes the case where mask layers 159R, 159G, and 159B are removed as an example, mask layers 159R, 159G, and 159B do not need to be removed. For example, if mask layers 159R, 159G, and 159B contain the aforementioned material having ultraviolet light shielding properties, it is preferable to proceed to the next step without removing the mask layers because this protects the organic compound layer from ultraviolet light.

[0484] The mask layer can be removed using the same method as the mask film processing method. By using a wet etching method, damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B during the mask layer removal can be reduced compared to the case of using a dry etching method.

[0485] Alternatively, the mask layer may be removed by dissolving it in a solvent such as water or alcohol. Examples of the alcohol include ethanol, methanol, isopropyl alcohol (IPA), and glycerin.

[0486] After removing the mask layer, a drying treatment may be performed to remove water contained in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, as well as water adsorbed on the surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. For example, heat treatment may be performed in an inert gas atmosphere or a reduced-pressure atmosphere. The heat treatment may 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. Using a reduced-pressure atmosphere is preferred because it allows drying at a lower temperature.

[0487] Then, if Figure 11B As shown, an inorganic insulating film 125f, which will later become the inorganic insulating layer 125, is formed to cover the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B.

[0488] As described later, an insulating film that will become an insulating layer 127 later is formed in a manner that contacts the top surface of the inorganic insulating film 125f. Therefore, the top surface of the inorganic insulating film 125f preferably has a high affinity with the material (such as a photosensitive resin composition containing an acrylic resin) used for the insulating film. In order to improve this affinity, surface treatment can also be performed to hydrophobize the top surface of the inorganic insulating film 125f (or improve its hydrophobicity). For example, it is preferably processed using a silanizing agent such as hexamethyldisilazane (HMDS). By making the top surface of the inorganic insulating film 125f hydrophobic, an insulating film 127f can be formed with high adhesion. In addition, as a surface treatment, the above-mentioned hydrophobization process can also be performed.

[0489] Then, if Figure 11C As shown in FIG. 1 , an insulating film 127 f which will later become the insulating layer 127 is formed on the inorganic insulating film 125 f.

[0490] The inorganic insulating film 125f and the insulating film 127f are preferably deposited using a formation method that causes less damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In particular, since the inorganic insulating film 125f is formed so as to contact the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, the inorganic insulating film 125f is preferably deposited using a formation method that causes less damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B than when the insulating film 127f is deposited.

[0491] Furthermore, the inorganic insulating film 125f and the insulating film 127f are each formed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By increasing the substrate temperature during deposition, the inorganic insulating film 125f can be formed even with a thin thickness, having a low impurity concentration and high barrier properties against at least one of water and oxygen.

[0492] The substrate temperature during formation of 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.

[0493] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm, 5 nm, or 10 nm and 200 nm, 150 nm, 100 nm, or 50 nm within the above-mentioned substrate temperature range.

[0494] The inorganic insulating film 125f is preferably formed using, for example, ALD. Using ALD is preferred because it reduces deposition damage and allows for deposition of a film with high coverage. For example, an aluminum oxide film is preferably formed using ALD as the inorganic insulating film 125f.

[0495] Alternatively, the inorganic insulating film 125f may be formed by sputtering, CVD, or PECVD, which have a higher deposition rate than ALD. This allows a highly reliable display device to be manufactured with high productivity.

[0496] The insulating film 127f is preferably formed using the aforementioned wet deposition method. For example, the insulating film 127f is preferably formed using a photosensitive material by spin coating, and more specifically, is preferably formed using a photosensitive resin composition containing an acrylic resin.

[0497] For example, it is preferred to form the insulating film 127f using a resin composition containing a polymer, an acid generator, and a solvent. The polymer is formed using one or more monomers and has a structure in which one or more structural units (also referred to as constituent units) are repeated regularly or irregularly. As the acid generator, one or both of a compound that generates an acid by irradiation with light and a compound that generates an acid by heating can be used. The resin composition may further include one or more of a photosensitizer, a sensitizer, a catalyst, an adhesive aid, a surfactant, and an antioxidant.

[0498] Furthermore, after forming the insulating film 127f, heat treatment (also called pre-baking) is preferably performed. This heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. The substrate temperature during the heat treatment is preferably 50°C to 200°C, more preferably 60°C to 150°C, and even more preferably 70°C to 120°C. This can remove the solvent in the insulating film 127f.

[0499] Next, exposure is performed to expose a portion of the insulating film 127f to visible light or ultraviolet light. Here, when a positive-type photosensitive resin composition containing an acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the region where the insulating layer 127 will not be formed in a later step. The insulating layer 127 is formed in the region sandwiched between any two of the conductive layers 152R, 152G, and 152B, as well as around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated onto the conductive layers 152R, 152G, 152B, and 152C. Note that when a negative-type photosensitive material is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the region where the insulating layer 127 will be formed.

[0500] The width of the insulating layer 127 to be formed later can be controlled by the exposed region of the insulating film 127f. In this embodiment, the insulating layer 127 is processed so that a portion overlaps with the top surface of the conductive layer 151.

[0501] The light used for exposure preferably includes i-line (wavelength: 365 nm). Alternatively, the light used for exposure may include at least one of g-line (wavelength: 436 nm) and h-line (wavelength: 405 nm).

[0502] Here, by providing an oxygen-blocking insulating layer (e.g., an aluminum oxide film) as one or both of the sacrificial layer 158 (sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B) and the inorganic insulating film 125f, diffusion of oxygen into the organic compound layers 103R, 103G, and 103B can be suppressed. When light (visible light or ultraviolet light) is irradiated onto the organic compound layer, the organic compound contained in the organic compound layer may become excited, thereby promoting reaction with oxygen in the atmosphere. Specifically, when light (visible light or ultraviolet light) is irradiated onto the organic compound layer in an oxygen-containing atmosphere, oxygen may bond to the organic compound contained in the organic compound layer. By providing the sacrificial layer 158 and the inorganic insulating film 125f on the island-shaped organic compound layer, bonding of oxygen in the atmosphere to the organic compound contained in the organic compound layer can be suppressed.

[0503] Then, if Figure 12AAs shown, development is performed to remove the exposed areas of insulating film 127f, thereby forming insulating layer 127a. Insulating layer 127a is formed in an area sandwiched between any two of conductive layers 152R, 152G, and 152B, and in an area surrounding conductive layer 152C. When an acrylic resin is used for insulating film 127f, an alkaline solution, such as TMAH, can be used as a developer.

[0504] Next, residues left during development (so-called scum) may be removed. For example, the residues may be removed by ashing using oxygen plasma.

[0505] Alternatively, etching may be performed to adjust the surface height of the insulating layer 127a. The insulating layer 127a may also be processed by, for example, ashing using oxygen plasma. Furthermore, if a non-photosensitive material is used as the insulating film 127f, the surface height of the insulating film 127f may also be adjusted by, for example, ashing.

[0506] Then, if Figure 12B As shown, an etching process is performed using insulating layer 127a as a mask to remove a portion of inorganic insulating film 125f, thereby reducing the thickness of a portion of sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B. Thus, inorganic insulating layer 125 is formed under insulating layer 127a. Furthermore, the surfaces of the thinner portions of sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B are exposed. Hereinafter, the etching process using insulating layer 127a as a mask may be referred to as the first etching process.

[0507] The first etching process can be performed by dry etching or wet etching. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layers 158R, 158G, and 158B, the first etching process can be performed at once, which is preferable.

[0508] By using the insulating layer 127 a having tapered side surfaces as a mask for etching, the side surfaces of the inorganic insulating layer 125 and the upper end portions of the side surfaces of the sacrificial layers 158R, 158G, and 158B can be tapered more easily.

[0509] When dry etching is performed, a chlorine-based gas is preferably used. As the chlorine-based gas, one gas selected from Cl2, BCl3, SiCl4, and CCl4, or a mixture of two or more thereof, can be used. Furthermore, one gas selected from oxygen, hydrogen, helium, and argon, or a mixture of two or more thereof, can be appropriately added to the chlorine-based gas. By utilizing dry etching, regions with reduced thickness in the sacrificial layers 158R, 158G, and 158B can be formed with excellent in-plane uniformity.

[0510] As a dry etching device, a dry etching device having a high-density plasma source can be used. For example, as a dry etching device having a high-density plasma source, an inductively coupled plasma (ICP: Inductively Coupled Plasma) etching device or the like can be used. Alternatively, a capacitively coupled plasma (CCP: Capacitively Coupled Plasma) etching device including parallel plate electrodes can b...

Claims

1. A light emitting device, comprising: a first electrode; a second electrode; as well as an organic compound layer between the first electrode and the second electrode, The organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer. The intermediate layer is located between the first light-emitting layer and the second light-emitting layer, The intermediate layer comprises a metal or a metal compound, a first organic compound, and a second organic compound different from the first organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound includes two or more heteroaromatic rings, The two or more heteroaromatic rings are bonded or fused to each other and include three or more heteroatoms in total, Furthermore, the second organic compound acts as a multidentate ligand and interacts with the metal or the metal compound through two or more of the three or more heteroatoms.

2. The light emitting device according to claim 1, The first organic compound and the metal or the metal compound interact to form a donor energy level, and acts as an electron donor for the second organic compound.

3. The light emitting device according to claim 1, The mass-to-charge ratio of the intermediate layer is detected by ToF-SIMS measurement, which is equivalent to the sum of the mass number of the first organic compound, the mass number of the second organic compound, and the mass number of the metal or the metal compound.

4. A light emitting device, comprising: a first electrode; a second electrode; as well as an organic compound layer between the first electrode and the second electrode, The organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer. The intermediate layer is located between the first light-emitting layer and the second light-emitting layer, The intermediate layer comprises a metal or a metal compound, a first organic compound, and a second organic compound different from the first organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound is an organic compound represented by the general formula (G1-1), And, A 1 , A 2 and A 3 Each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms.

5. A light emitting device, comprising: a first electrode; a second electrode; as well as an organic compound layer between the first electrode and the second electrode, The organic compound layer includes a first light-emitting layer, a second light-emitting layer and an intermediate layer. The intermediate layer is located between the first light-emitting layer and the second light-emitting layer, The intermediate layer comprises a metal or a metal compound, a first organic compound, and a second organic compound different from the first organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound is an organic compound represented by the general formula (G1-2), A 1 and A 2 each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, And, A 1 Contains more than two nitrogen atoms.

6. A light emitting device, comprising: A first light emitting device and a second light emitting device on the same insulating surface, Wherein, the first light emitting device is the light emitting device according to claim 1, The second electrode is commonly used by the first light emitting device and the second light emitting device. Furthermore, the first light-emitting layer, the intermediate layer, and the second light-emitting layer have profiles that are aligned or substantially aligned. 7 . The light-emitting device according to claim 1 , wherein the second organic compound interacts with the metal or the metal compound as a bidentate ligand or a tridentate ligand via two or more of the three or more heteroatoms.

8. The light emitting device according to claim 1, The heteroatoms are all nitrogen atoms.

9. A light emitting device, comprising: A first light emitting device and a second light emitting device on the same insulating surface, Wherein, the first light emitting device is the light emitting device according to claim 4, The second electrode is commonly used by the first light emitting device and the second light emitting device. Furthermore, the first light-emitting layer, the intermediate layer, and the second light-emitting layer have profiles that are aligned or substantially aligned. 10 . The light emitting device according to claim 4 , wherein the second organic compound interacts with the metal or the metal compound via a nitrogen atom as a tridentate ligand.

11. A light emitting device, comprising: A first light emitting device and a second light emitting device on the same insulating surface, Wherein, the first light emitting device is the light emitting device according to claim 5, The second electrode is commonly used by the first light emitting device and the second light emitting device. Furthermore, the first light-emitting layer, the intermediate layer, and the second light-emitting layer have profiles that are aligned or substantially aligned. 12 . The light emitting device according to claim 5 , wherein the second organic compound interacts with the metal or the metal compound via a nitrogen atom as a bidentate ligand. The light emitting device according to claim 1 , wherein the heteroaromatic ring is a π-electron-deficient heteroaromatic ring.

14. The light emitting device according to claim 1, wherein the heteroaromatic ring comprises at least one of a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, and a triazole ring. 15 . The light emitting device according to claim 1 , wherein at least one of the two or more heteroaromatic rings comprises a pyrazine ring, a pyrimidine ring, a pyridazine ring or a triazine ring. The light emitting device according to claim 1 , wherein the two or more heteroaromatic rings include three or more pyridine rings in total. The light emitting device according to claim 1 , wherein the first organic compound has an electron donating group. 18 . The light emitting device according to claim 17 , wherein the electron donating group comprises at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group. The light emitting device according to claim 1 , wherein the first organic compound has an acidity coefficient pKa of 8 or more.

20. The light emitting device according to claim 1, wherein the first organic compound includes a phenanthroline ring.

21. The light emitting device according to claim 1, wherein the glass transition temperature T g It is above 100°C. 22 . The light emitting device according to claim 1 , wherein a LUMO energy level of the second organic compound is lower than a LUMO energy level of the first organic compound.

23. The light emitting device according to claim 1, wherein the metal belongs to Group 1, Group 3, Group 11 or Group 13 of the periodic table.

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