Light-emitting device

Abstract

To provide a light-emitting device having high reliability.SOLUTION: A light-emitting device includes a first electrode, a second electrode, and an EL layer. The EL layer is located between the first electrode and the second electrode. The EL layer has a light-emitting layer and an electron injection layer. The electron injection layer contains a metal or a meal oxide, a first organic compound, and a second organic compound. The first organic compound is an organic compound containing a first π-electron-deficient heteroaromatic ring with an electron-donating group. The second organic compound is an organic compound containing a second π-electron-deficient heteroaromatic ring. A LUMO level of the second organic compound is smaller than a LUMO level of the first organic compound by 0.20 eV or more.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the invention relates to a light emitting device.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), a driving method thereof, or a manufacturing method thereof. [Background technology]

[0003] Display devices have been developed for various applications in recent years. For example, applications of large display devices include home television devices (also called televisions or television receivers), digital signage, and public information displays (PIDs), while applications of small display devices include smartphones and tablet terminals equipped with touch panels.

[0004] At the same time, there is a demand for display devices with higher resolution. Devices requiring high-resolution display devices include, for example, devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), which are being actively developed.

[0005] As a display element used in a display device, the development of a light-emitting device (also called a light-emitting element) is being actively promoted. A light-emitting device (also called an EL device or an EL element) utilizing the electroluminescence (hereinafter referred to as EL) phenomenon, particularly an organic EL device mainly using an organic compound, has characteristics such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power source, and is therefore suitable for a display device.

[0006] In order to obtain a higher-definition light-emitting device using an organic EL device, research is being conducted on patterning the organic layer by photolithography using photoresist, etc., instead of deposition using a metal mask. By using photolithography, a high-definition display device with an EL layer spacing of several μm can be obtained (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2018-521459 [Patent Document 2] International Publication No. 2021 / 045178 Summary of the Invention [Problem to be solved by the invention]

[0008] It has long been known that the initial characteristics and reliability of the EL layer of an organic EL device (also referred to as a light-emitting device in this specification) are affected when it is exposed to atmospheric components such as water and oxygen, and it has been common knowledge that it should be handled in a near-vacuum atmosphere. In particular, alkali metals or alkaline earth metals, or compounds of these, are used for the electron injection layer, but these metals and compounds are highly reactive with water or oxygen, and when the surface of the EL layer is exposed to the atmosphere, they deteriorate in an instant and no longer function as an electron injection layer.

[0009] However, in the process of processing by photolithography as described above, it is unavoidable to expose the surface of the EL layer to the air.

[0010] An object of one aspect of the present invention is to provide a novel light-emitting device. Or, an object of another aspect of the present invention is to provide a light-emitting device having good efficiency. Or, an object of one aspect of the present invention is to provide a light-emitting device having good reliability. Or, an object of another aspect of the present invention is to provide a light-emitting device having good efficiency and reliability.

[0011] Alternatively, one embodiment of the present invention has an object to provide a novel light-emitting device manufactured through a photolithography process. Alternatively, another embodiment of the present invention has an object to provide a light-emitting device manufactured through a photolithography process and having good efficiency. Alternatively, one embodiment of the present invention has an object to provide a light-emitting device manufactured through a photolithography process and having good reliability. Alternatively, another embodiment of the present invention has an object to provide a light-emitting device manufactured through a photolithography process and having good luminous efficiency and reliability.

[0012] Alternatively, an object of one embodiment of the present invention is to provide a novel light-emitting device that can be used in a high-definition display device. Alternatively, an object of another embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device and has good efficiency. Alternatively, an object of one embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device and has good reliability. Alternatively, an object of another embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device and has good emission efficiency and reliability.

[0013] Another object of another embodiment of the present invention is to provide a highly reliable display device. Another object of another embodiment of the present invention is to provide a high-definition display device. Another object of another embodiment of the present invention is to provide a high-definition and highly reliable display device.

[0014] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description of the specification, drawings, and claims. [Means for solving the problem]

[0015] One embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, and an EL layer. The EL layer is located between the first electrode and the second electrode. The EL layer has a light-emitting layer and an electron injection layer. The electron injection layer is a mixed layer containing a metal or a metal oxide, a first organic compound, and a second organic compound. The first organic compound is an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring. The LUMO level of the second organic compound is lower by 0.20 eV or more than the LUMO level of the first organic compound.

[0016] Alternatively, another embodiment of the present invention is one of a plurality of light-emitting devices included in a light-emitting device group having a first electrode group formed on the same insulating surface, a second electrode group facing the first electrode group, and an EL layer group located between the first electrode group and the second electrode group, in which the light-emitting device has a first electrode, a second electrode, and an EL layer, the first electrode being one of the first electrode group, and the first electrode being independent for each of the plurality of light-emitting devices, the EL layer being one of the EL layer group, and the EL layer being independent for each of the plurality of light-emitting devices, the second electrode being a continuous conductive layer shared by the plurality of light-emitting devices, and the second electrode and the EL the layer overlaps the first electrode, the EL layer has an emitting layer and an electron injection layer, the electron injection layer is a mixed layer containing a metal or a metal oxide, a first organic compound, and a second organic compound, the first organic compound is an organic compound containing a first π-electron deficient heteroaromatic ring having an electron donating group, the second organic compound is an organic compound having a second π-electron deficient heteroaromatic ring, the LUMO level of the second organic compound is lower by 0.20 eV or more than the LUMO level of the first organic compound, and the distance between the EL layer of the light-emitting device and the EL layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

[0017] Alternatively, another embodiment of the present invention is a light-emitting device including a first electrode, a second electrode, and an EL layer, the EL layer being located between the first electrode and the second electrode, the EL layer including a light-emitting layer and an electron-injection layer, the electron-injection layer having a stacked structure of a first layer including a metal and a second layer including a first organic compound and a second organic compound, the first layer being located closer to the cathode than the second layer, the first organic compound being an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound being an organic compound including a second π-electron-deficient heteroaromatic ring, and the LUMO level of the second organic compound being lower by 0.20 eV or more than the LUMO level of the first organic compound.

[0018] Alternatively, another embodiment of the present invention is one of a plurality of light-emitting devices included in a light-emitting device group having a first electrode group formed on the same insulating surface, a second electrode group facing the first electrode group, and an EL layer group located between the first electrode group and the second electrode group, the light-emitting device having a first electrode, a second electrode, and an EL layer, the first electrode being one of the first electrode group, and the first electrode being independent for each of the plurality of light-emitting devices, the EL layer being one of the EL layer group, and the EL layer being independent for each of the plurality of light-emitting devices, the second electrode being a continuous conductive layer shared by the plurality of light-emitting devices, the second electrode and the EL layer overlapping the first electrode, the L layer has a light-emitting layer and an electron injection layer, the electron injection layer has a laminated structure of a first layer containing a metal and a second layer containing a first organic compound and a second organic compound, the first layer is located closer to the cathode than the second layer, the first organic compound is an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring, the LUMO level of the second organic compound is smaller by 0.20 eV or more than the LUMO level of the first organic compound, and the distance between the EL layer of the light-emitting device and the EL layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

[0019] Another embodiment of the present invention is a light-emitting device having the above structure, in which the LUMO level of the first organic compound is LUMO1 (eV), and the LUMO level of the second organic compound (LUMO2 (eV)) satisfies LUMO1-0.80≦LUMO2≦LUMO1-0.20.

[0020] Another embodiment of the present invention is a light-emitting device having the above structure, in which the LUMO level of the first organic compound is LUMO1 (eV), and the LUMO level of the second organic compound (LUMO2 (eV)) satisfies LUMO1-0.80≦LUMO2≦LUMO1-0.30.

[0021] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first π-electron-deficient heteroaromatic ring is a heteroaromatic ring including two or more pyridine rings.

[0022] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first organic compound has an acid dissociation constant pKa of 8 or more.

[0023] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different from each other.

[0024] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has an azole ring (an imidazole ring, a pyrazole ring, an oxazole ring, or a thiazole ring), a triazole ring, a diazine ring (a pyrazine ring, a pyrimidine ring, or a pyridazine ring), or a triazine ring.

[0025] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has an acid dissociation constant pKa of less than 4.

[0026] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting layer includes a third organic compound, and the third organic compound has a third π-electron-deficient heteroaromatic ring that is the same as the second π-electron-deficient heteroaromatic ring.

[0027] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting layer contains a third organic compound, and the third organic compound is the same organic compound as the second organic compound.

[0028] Another embodiment of the present invention is a light-emitting device having the above structure, which includes an electron-transport layer between the light-emitting layer and the electron-injection layer, and the electron-transport layer includes a fourth organic compound that is different from the third organic compound.

[0029] Another embodiment of the present invention is a light-emitting device having the above structure, in which the metal is a metal belonging to any one of Groups 3, 11, and 13 of the periodic table.

[0030] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first π-electron-deficient heteroaromatic ring includes a phenanthroline ring.

[0031] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is a 1,10-phenanthroline ring and has an electron-donating group at least at one of the 4-position and the 7-position.

[0032] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron-donating group is one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

[0033] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first organic compound has an acid dissociation constant pKa of 8 or more.

[0034] Alternatively, in the above-described structure, the minimum value of the electrostatic potential of the first organic compound is a threshold value of the electron density distribution in atomic units of 0.0004e / a0 3 In the case of -0.085E h A light emitting device comprising:

[0035] Alternatively, in the above structure, another embodiment of the present invention is a method for manufacturing an electron injection layer having a spin density of 5×10 16 spins / cm 3 The above is a light emitting device.

[0036] Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned structure, in which the electron injection layer is located between the second electrode and the light-emitting layer. Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned structure, which has a hole injection layer, the hole injection layer being located between the first electrode and the light-emitting layer, and which contains a fifth organic compound having a hole-transporting property and a first substance having an acceptor property to the fifth organic compound. Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned structure, in which the hole injection layer contains a fifth organic compound having a hole-transporting property and an organic compound having four or more of at least one of halogen groups and cyano groups. Alternatively, another embodiment of the present invention is a light-emitting device having the above-mentioned structure, in which the hole injection layer contains a fifth organic compound having a hole-transporting property and a metal or a metal oxide different from the metal or metal oxide contained in the electron injection layer.

[0037] In another embodiment of the present invention, the hole injection layer has a spin density of 1×10 17 spins / cm 3 The above is a light emitting device.

[0038] Alternatively, another embodiment of the present invention is a light-emitting device having a plurality of light-emitting devices, each of which is any of the light-emitting devices described above. Each of the plurality of light-emitting devices has an EL layer including a light-emitting layer and an electron-injection layer between a first electrode and a second electrode, and the EL layer of each of the plurality of light-emitting devices is independent from one another.

[0039] Another embodiment of the present invention is a display module including the above-described light-emitting device and at least one of a connector and an integrated circuit.

[0040] Another embodiment of the present invention is an electronic device including any of the above light-emitting devices and at least one of a housing, a battery, a camera, a speaker, and a microphone. Effect of the Invention

[0041] According to one embodiment of the present invention, a novel light-emitting device can be provided. According to another embodiment of the present invention, a light-emitting device having good efficiency can be provided. According to one embodiment of the present invention, a light-emitting device having good reliability can be provided. According to another embodiment of the present invention, a light-emitting device having good efficiency and reliability can be provided.

[0042] Alternatively, according to one embodiment of the present invention, a novel light-emitting device manufactured through a photolithography process can be provided. Alternatively, according to another embodiment of the present invention, a light-emitting device manufactured through a photolithography process and having good efficiency can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device manufactured through a photolithography process and having good reliability can be provided. Alternatively, according to another embodiment of the present invention, a light-emitting device manufactured through a photolithography process and having good emission efficiency and reliability can be provided.

[0043] According to one embodiment of the present invention, a novel light-emitting device that can be used in a high-definition display device can be provided. According to another embodiment of the present invention, a light-emitting device that can be used in a high-definition display device and has good efficiency can be provided. According to one embodiment of the present invention, a light-emitting device that can be used in a high-definition display device and has good reliability can be provided. According to another embodiment of the present invention, a light-emitting device that can be used in a high-definition display device and has good emission efficiency and reliability can be provided.

[0044] According to another embodiment of the present invention, a highly reliable display device can be provided. According to another embodiment of the present invention, a high-definition display device can be provided. According to another embodiment of the present invention, a high-definition and highly reliable display device can be provided.

[0045] According to another embodiment of the present invention, a novel organic compound, a novel light-emitting device, a novel display device, a novel display module, or a novel electronic device can be provided.

[0046] 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 these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims. [Brief description of the drawings]

[0047] [Figure 1] FIG. 1 is a diagram illustrating a light emitting device. [Diagram 2] 2(A) and 2(B) are diagrams illustrating a light emitting device. [Diagram 3] 3(A) and 3(B) are a top view and a cross-sectional view of the light emitting device. [Figure 4] 4A to 4E are cross-sectional views showing an example of a method for manufacturing a display device. [Diagram 5] 5A and 5B are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 6] 6A to 6D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 7] 7A to 7C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 8] 8A to 8C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 9] 9A to 9C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 10] 10A and 10B are perspective views showing a configuration example of a display module. [Figure 11] 11A and 11B are cross-sectional views showing a configuration example of a display device. [Figure 12] FIG. 12 is a perspective view showing a configuration example of a display device. [Figure 13] FIG. 13 is a cross-sectional view showing a configuration example of a display device. [Figure 14] FIG. 14 is a cross-sectional view showing a configuration example of a display device. [Figure 15] FIG. 15 is a cross-sectional view showing a configuration example of a display device. [Figure 16] 16A to 16D are diagrams illustrating examples of electronic devices. [Figure 17] 17A to 17F are diagrams illustrating examples of electronic devices. [Figure 18] 18A to 18G are diagrams illustrating examples of electronic devices. [Figure 19] 19(A) and 19(B) show the analysis results of the spin density distribution in the ground state of the composite material. [Figure 20] 20(A) and 20(B) show the results of electrostatic potential map analysis of an organic compound in the ground state. [Figure 21] 21(A) to 21(C) show the results of electrostatic potential map analysis of the composite material in the ground state. [Figure 22] 22(A) and 22(B) are diagrams illustrating a light-emitting device. [Diagram 23] 23A to 23C are cross-sectional views showing configuration examples of a display device. [Figure 24] 24A to 24C are cross-sectional views showing configuration examples of a display device. [Diagram 25] FIG. 25 is a graph showing the luminance-current density characteristics of the light-emitting device 1-1, the light-emitting device 1-2, and the comparative light-emitting device 1. In FIG. [Figure 26] FIG. 26 is a graph showing the luminance-voltage characteristics of the light-emitting device 1-1, the light-emitting device 1-2, and the comparative light-emitting device 1. In FIG. [Figure 27] FIG. 27 is a graph showing the current efficiency-current density characteristics of the light-emitting device 1-1, the light-emitting device 1-2, and the comparative light-emitting device 1. In FIG. [Figure 28]FIG. 28 is a graph showing current density-voltage characteristics of the light-emitting device 1-1, the light-emitting device 1-2, and the comparative light-emitting device 1. In FIG. [Figure 29] FIG. 29 shows electroluminescence spectra of light-emitting device 1-1, light-emitting device 1-2 and comparative light-emitting device 1. As shown in FIG. [Diagram 30] FIG. 30 is a graph showing the luminance-current density characteristics of the light-emitting device 2-1, the light-emitting device 2-2, the comparative light-emitting device 2-1, and the comparative light-emitting device 2-2. [Diagram 31] FIG. 31 is a graph showing the luminance-voltage characteristics of the light-emitting device 2-1, the light-emitting device 2-2, the comparative light-emitting device 2-1, and the comparative light-emitting device 2-2. [Diagram 32] FIG. 32 is a graph showing the current efficiency-current density characteristics of the light-emitting device 2-1, the light-emitting device 2-2, the comparative light-emitting device 2-1, and the comparative light-emitting device 2-2. [Diagram 33] FIG. 33 is a graph showing the current density-voltage characteristics of the light-emitting device 2-1, the light-emitting device 2-2, the comparative light-emitting device 2-1, and the comparative light-emitting device 2-2. [Diagram 34] FIG. 34 shows electroluminescence spectra of light-emitting device 2-1, light-emitting device 2-2, comparative light-emitting device 2-1, and comparative light-emitting device 2-2. [Diagram 35] FIG. 35 is a diagram showing the relationship between the LUMO level of the second organic compound and the voltage increase due to processing by a photolithography method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0048] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the modes and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0049] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-definition metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0050] (Embodiment 1) As one of the methods for forming an organic semiconductor film into a specified shape, a vacuum deposition method using a metal mask (mask deposition) is widely used. However, in recent years, as density and definition have increased, mask deposition is approaching its limit for further finer definition due to various reasons, such as problems with alignment accuracy and problems with the placement distance to the substrate. On the other hand, it is expected that organic semiconductor devices with more precise patterns can be realized by processing the shape of the organic semiconductor film using a photolithography method. Furthermore, since photolithography is easier to produce large areas than mask deposition, research on processing organic semiconductor films using photolithography is being conducted.

[0051] On the other hand, it has long been known that the initial characteristics and reliability of the EL layer in an organic EL device can be affected when exposed to atmospheric components such as water and oxygen, and so it has been common knowledge that they should be handled in a near-vacuum atmosphere.

[0052] In particular, alkali metals or alkaline earth metals, or compounds thereof (hereinafter also referred to as Li compounds, etc.) are often used in the electron injection layer of light-emitting devices. However, these Li compounds, etc. are highly reactive with water or oxygen and deteriorate in an instant when merely exposed to the atmosphere, and no longer function as an electron injection layer.

[0053] However, in the process of processing by the photolithography method as described above, it is necessary to expose the surface of the EL layer to the air. Therefore, when processing by the photolithography method is performed, the electron injection property of the electron injection layer using an alkali metal compound or the like is significantly reduced. As a result, an organic EL device having an electron injection layer using an alkali metal compound or the like and processed by the photolithography method has an increased driving voltage, making it difficult to obtain good characteristics.

[0054] Here, the inventors have found that by using, as the electron injection layer, a layer containing a metal or a metal oxide, an organic compound (first organic compound) containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, it is possible to obtain an organic EL device having good characteristics even after undergoing a photolithography process involving exposure of the EL layer to the atmosphere.

[0055] In other words, by using a layer containing a metal or metal oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound having a second π-electron-deficient heteroaromatic ring as the electron injection layer, it is possible to obtain an organic EL device having good characteristics even after undergoing a photolithography process involving exposure of the EL layer to the atmosphere.

[0056] Furthermore, in one embodiment of the present invention, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound, and is preferably at least 0.80 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound. It is more preferable that the LUMO level is not more than 0.25 eV lower than the LUMO level of the first organic compound, more preferably that the LUMO level is at least 0.50 eV lower than the LUMO level of the first organic compound and not more than 0.30 eV lower than the LUMO level of the first organic compound, more preferably that the LUMO level is at least 0.50 eV lower than the LUMO level of the first organic compound and not more than 0.35 eV lower than the LUMO level of the first organic compound, and more preferably that the LUMO level is at least 0.50 eV lower than the LUMO level of the first organic compound and not more than 0.40 eV lower than the LUMO level of the first organic compound.

[0057] That is, assuming that the LUMO level of the first organic compound is "LUMO1 (eV)" and the LUMO level of the second organic compound is "LUMO2 (eV)", it is preferable that LUMO2 satisfies the following formula (1). LUMO1-0.80≦LUMO2≦LUMO1-0.20 Formula (1)

[0058] It is more preferable that LUMO2 satisfies the following formula (2). LUMO1-0.50≦LUMO2≦LUMO1-0.20 Formula (2)

[0059] It is more preferable that LUMO2 satisfies the following formula (3). LUMO1-0.50≦LUMO2≦LUMO1-0.25 Formula (3)

[0060] It is more preferable that LUMO2 satisfies the following formula (4). LUMO1-0.50≦LUMO2≦LUMO1-0.30 Formula (4)

[0061] It is more preferable that LUMO2 satisfies the following formula (5). LUMO1-0.50≦LUMO2≦LUMO1-0.35 Formula (5)

[0062] It is more preferable that LUMO2 satisfies the following formula (6). LUMO1-0.50≦LUMO2≦LUMO1-0.40 Formula (6)

[0063] When LUMO2 is in the above range, the light-emitting device according to one embodiment of the present invention can have favorable characteristics such as a low driving voltage, regardless of whether or not it is subjected to a photolithography process involving exposure of the EL layer to the atmosphere, and can also have favorable reliability.

[0064] The metal or metal oxide, the first organic compound, and the second organic compound interact with each other to form a donor level (SOMO level or HOMO level). This reduces the barrier for electron injection into the electron transport layer, and allows electrons to be smoothly injected and transported into the electron transport layer without using a conventional electron injection layer that is unstable and deteriorates significantly after a photolithography process involving exposure to the atmosphere. Furthermore, by having LUMO2 in the above range, it is possible to form an electron injection layer that can interact more stably and is less likely to deteriorate even after a photolithography process involving exposure to the atmosphere. Therefore, even after a photolithography process involving exposure of the EL layer to the atmosphere, it is possible to smoothly inject and transport electrons into the electron transport layer, suppressing an increase in driving voltage, and enabling a highly reliable light-emitting device to be fabricated using a photolithography process.

[0065] 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 ​​between different compounds, it is preferable to use values ​​estimated by the same measurement.

[0066] In this manner, by using an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having an electron-donating group, an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, and a metal or metal oxide in the electron-injection layer, an electron-injection layer that is resistant to oxygen and water in the air, as well as water and chemicals used in the lithography process can be formed. Therefore, one embodiment of the present invention can provide a light-emitting device that has excellent moisture resistance, water resistance, oxygen resistance, and chemical resistance, a low driving voltage, and good luminous efficiency.

[0067] The electron injection layer containing an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having an electron-donating group, an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, and a metal or metal oxide is preferably a mixed layer of the metal or metal oxide, the first organic compound, and the second organic compound. Also, a laminate structure of a layer containing a metal, a layer containing the first organic compound, and a layer containing the second organic compound is preferable.

[0068] When the electron injection layer has a laminated structure of a layer containing a metal, and a layer containing a first organic compound and a second organic compound, it is preferable that the layer containing a metal is on the cathode side, the layers containing the first organic compound and the second organic compound are on the anode side and are laminated in contact with each other, and the layers containing the first organic compound and the second organic compound are in contact with the electron transport layer.

[0069] When the electron injection layer is a mixed layer of a metal or metal oxide, a first organic compound, and a second organic compound, the number of layers can be reduced compared to a laminated structure, which increases productivity and facilitates mass production.

[0070] In addition, when alkali metals or alkaline earth metals and their oxides, such as lithium oxide (Li2O), are used in the electron injection layer of an organic EL device having a conventional structure, light-emitting devices manufactured through a vacuum integrated process exhibit good characteristics. However, as described above, when the device is manufactured through a photolithography process involving exposure of the EL layer to the atmosphere, the driving voltage of the light-emitting device using alkali metals or alkaline earth metals and their oxides in the electron injection layer is significantly increased compared to light-emitting devices manufactured through a vacuum integrated process. This is thought to be due to the deterioration of the alkali metal or alkaline earth metal oxide due to exposure to the atmosphere, as described above, resulting in a decrease in donor properties.

[0071] That is, in another embodiment of the present invention, by using an organic compound (first organic compound) containing an oxide of an alkali metal or alkaline earth metal such as lithium oxide (LiO) and a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring in the electron injection layer, it is possible to obtain an organic EL device having excellent characteristics similar to those of a light-emitting device fabricated by a vacuum integrated process, even if the organic EL device is fabricated via a photolithography process involving exposure to air.

[0072] This is because, by using an alkali metal or alkaline earth metal and its oxide, a first organic compound containing a first π-electron-deficient heteroaromatic ring having electron donating properties, and a second organic compound having a second π-electron-deficient heteroaromatic ring in the electron injection layer, a donor level (SOMO level or HOMO level) is formed by interaction, and the absolute value of the stabilization energy by the interaction is large and the energy level is high, so that the barrier for electron injection from the electron injection layer to the electron transport layer is reduced even after exposure to the atmosphere, and a configuration can be formed in which electrons are smoothly injected and transported to the electron transport layer. This makes it possible to obtain an organic EL device with good characteristics in which the increase in driving voltage is suppressed even after exposure to the atmosphere.

[0073] In this way, the light-emitting device according to one embodiment of the present invention, in which a layer containing an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring is used as the electron injection layer, can realize an organic EL device having good characteristics even after a step of exposing the EL layer to the atmosphere. That is, by applying the configuration of one embodiment of the present invention, an organic EL device having good characteristics can be realized, which is manufactured by a photolithography method including a step of exposing the EL layer to the atmosphere. This makes it possible to provide a display device with very high resolution and good characteristics.

[0074] ≪Electron injection layer≫ As described above, the electron injection layer is provided between the cathode and the light-emitting layer, and contains an organic compound having a first π-electron-deficient heteroaromatic ring having a metal or a metal oxide and an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound).

[0075] <Metal or metal oxide> The metal or metal oxide contained in the electron injection layer may be a metal or an oxide thereof, including alkali metals (Group 1 elements) such as Li, alkaline earth metals (Group 2 elements) such as Mg and Ca, Group 3 elements including lanthanides such as Y, Eu and Yb, Group 11 elements such as Cu, Ag and Au, earth metals (Group 13 elements) such as Al and In, and Group 14 elements such as Sn.

[0076] When an alkali metal, an alkaline earth metal, or an oxide thereof is used as the metal or metal oxide, the donor level formed by interaction with the first organic compound and the second organic compound can be made to be a high energy level, and electrons can be smoothly injected and transported from the cathode to the electron injection layer, so that a light-emitting device that emits light with a low driving voltage and high luminous efficiency can be provided. In addition, transition metals and their oxides are preferred because they are stable and have low reactivity with components such as water and oxygen in the atmosphere. Among the above, it is preferred to use a metal or metal oxide containing an element belonging to an odd group (Group 1, Group 3, Group 11, or Group 13) of the periodic table, because it is easy to interact with the first organic compound and the second organic compound and easy to form a donor level.

[0077] In addition, metals or metal oxides that have a low melting point and can be formed into a film by vacuum deposition are preferred because they can easily form a mixed layer or laminate with an organic compound. Specifically, for example, metals or metal oxides of Group 11 elements and Group 13 elements have a low melting point and can be suitably used for vacuum deposition. In addition, metals or metal oxides of Group 11 elements and Group 13 elements are preferred because they are stable to oxygen and water in the atmosphere. As metals or metal oxides that can be formed into a film by vacuum deposition, the melting point at normal pressure is preferably 2000°C or less, preferably 1500°C or less, and more preferably 1000°C or less, or the sublimation temperature under reduced pressure (vacuum of 1 Pa or less) is preferably 1500°C or less, preferably 1000°C or less, and more preferably 500°C or less.

[0078] Specifically, the metal or metal oxide may be, for example, lithium, magnesium, calcium, silver, indium, or an oxide thereof. Note that even if the metal is a single substance, it may be oxidized to a metal oxide during a process such as film formation or exposure to the atmosphere.

[0079] Specific examples of such metal materials are particularly preferred, including lithium, magnesium, calcium, ytterbium, silver, aluminum, and indium.

[0080] <First organic compound> The first organic compound contained in the electron injection layer can be an organic compound having a π-electron-deficient heteroaromatic ring. It is more preferable to use an organic compound having a π-electron-deficient heteroaromatic ring having an electron-donating group as the first organic compound, since the electron density of the π-electron-deficient heteroaromatic ring can be increased.

[0081] As the organic compound having a π-electron-deficient heteroaromatic ring, an organic compound having a nitrogen-containing heteroaromatic ring is preferred, and as the nitrogen-containing heteroaromatic ring, a pyridine ring is preferred, and an organic compound having a heteroaromatic ring containing two or more pyridine rings is particularly preferred. This is because the two nitrogen atoms contained in the organic compound having a heteroaromatic ring containing two or more pyridine rings are coordinated to a metal or metal oxide, which makes it easier for interaction with the metal or metal oxide to occur.

[0082] Among organic compounds having heteroaromatic rings containing two or more pyridine rings, organic compounds having a bipyridine skeleton are preferred because the nitrogen atom is more likely to coordinate to a metal or metal oxide, and therefore interactions with the metal or metal oxide occur easily. Furthermore, phenanthroline rings are preferred because they are rigid and stable. In particular, organic compounds having a 1,10-phenanthroline ring are preferred because the two nitrogen atoms contained therein are located at positions that make it easy to coordinate to a metal or metal oxide, and therefore interactions with the metal or metal oxide occur easily.

[0083] When an electron-donating group is introduced into the 1,10-phenanthroline ring, the electron-donating group is preferably substituted at positions 4 and 7 of the 1,10-phenanthroline ring. By introducing an electron-donating group into positions 4 and 7 of the 1,10-phenanthroline ring, the electron density of the nitrogen atoms at positions 1 and 10 can be increased, making it easier for the nitrogen atoms to interact with a metal or metal oxide.

[0084] Examples of the electron donating group of the π-electron deficient heteroaromatic ring include an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group. However, the electron donating group that is preferably introduced into the π-electron deficient heteroaromatic ring is not limited to these. Any group that can increase the electron density of the π-electron deficient heteroaromatic ring by introducing it into the π-electron deficient heteroaromatic ring can be used as the electron donating group. In addition, the electron donating group may be introduced into the π-electron deficient heteroaromatic ring via an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0085] Specific examples of alkyl groups that can be used as the electron-donating group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group.

[0086] Specific examples of alkoxy groups that can be used as the electron-donating 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-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a tert-pentyloxy group, a neopentyloxy group, an n-hexyloxy group, an isohexyloxy group, a sec-hexyloxy group, a tert-hexyloxy group, and a neohexyloxy group.

[0087] Specific examples of the aryloxy group that can be used as the electron-donating 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, a 2-fluorenyloxy group, etc. The aryloxy group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, etc.

[0088] Specific examples of the alkylamino group that can be used as the electron donating group include a dimethylamino group and a diethylamino group.

[0089] Specific examples of the arylamino group that can be used as the electron-donating group include a diphenylamino group, a bis(α-naphthyl)amino group, a bis(m-tolyl)amino group, etc. The arylamino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, etc.

[0090] Specific examples of heterocyclic amino groups that can be used as the electron donating group include groups represented by the following structural formulas (R-1) to (R-26). The heterocyclic amino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0091] [ka]

[0092] In addition, the group represented by the structural formula (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17) or (R-21) is more preferable as the electron donating group. Among them, the group represented by the structural formula (R-3), (R-4), (R-8) or (R-21) is preferable because it has high electron donating property and can further increase the electron density of the phenanthroline ring.

[0093] Specific examples of the electron-donating group include groups represented by the following structural formulas (R-27) and (R-28).

[0094] [ka]

[0095] The organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound may have both the above-mentioned electron-donating group and other substituents. In addition to the above-mentioned electron-donating group, a specific example of a substituent that can be introduced into the π-electron-deficient heteroaromatic ring is an aryl group. Specific examples of the aryl group include a phenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a mesityl group, an o-biphenyl group, a m-biphenyl group, a p-biphenyl group, a 1-naphthyl group, a 2-naphthyl group, and a 2-fluorenyl group. The aryl group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0096] Specific examples of organic compounds having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound are shown in structural formulas (100) to (111). Note that the organic compounds that can be used as the first organic compound are not limited to these.

[0097] [ka]

[0098] It is preferable that the first organic compound has a small minimum negative value (large absolute negative value) of electrostatic potential (ESP) since the absolute value of stabilization energy due to interaction with the metal or metal oxide is large.

[0099] In an organic compound having a π-electron-deficient heteroaromatic ring, the electrostatic potential around the heteroatom of the π-electron-deficient heteroaromatic ring tends to be negative. However, by introducing an electron-donating group into the π-electron-deficient heteroaromatic ring, the electrostatic potential around the heteroatom of the π-electron-deficient heteroaromatic ring can be further reduced (the absolute value of the negative potential can be increased).

[0100] The electrostatic potential is the interaction energy between a positive point charge with a unit charge and the electron distribution of a molecule. The value of the electrostatic potential also changes depending on the threshold of the electron density.

[0101] In order to increase the efficiency of the interaction with a metal or metal oxide, it is preferable that the minimum value of the electrostatic potential of the first organic compound is smaller (more negatively) than the minimum value of the electrostatic potential of the unsubstituted π-electron-deficient heteroaromatic ring.

[0102] Specifically, the threshold of the electron density distribution in atomic units is set to 0.0004e / a0 3 (e is the elementary charge (1e=1.60218×10 -19 C), a0 is the Bohr radius (1a0=5.29177×10 -11 m)), the minimum value of the electrostatic potential of the first organic compound is -0.085E h (E h is the Hartree energy (1E h =27.211eV) or less is preferable, -0.090E h More preferably, the threshold of the electron density distribution is 0.003e / a0 3 The minimum electrostatic potential of the first organic compound is -0.12E h Less than or equal to -0.13E is preferredh The ESP of the first organic compound is more preferably 0.0004e / a0 or less. 3 The minimum value is -0.085E h The threshold of the electron density distribution is 0.003e / a0 3 The minimum value is -0.12E h It is even more preferable that:

[0103] The minimum electrostatic potential (ESP) values ​​of the organic compounds represented by the above structural formulas (100) to (107) and structural formula (111), as well as BPhen, mPPhen2P, NBPhen, and Phen, which are shown as organic compounds that can be used for the first organic compound, were estimated by quantum chemical calculation. The structural formulas of the organic compounds represented by the structural formulas (100) to (107), the organic compound represented by the structural formula (111), BPhen, mPPhen2P, NBPhen, and Phen are shown below.

[0104] [ka]

[0105] Gaussian09 was used as the quantum chemical calculation program. Calculations were performed using an SGI8600 manufactured by HPE. The most stable structure in the ground state of each organic compound was calculated using density functional theory (DFT). 6-311G(d,p) was used as the basis function, and B3LYP was used as the functional.

[0106] Table 1 shows the analysis results of the electrostatic potential in the ground state of each organic compound. The electrostatic potential is the interaction energy between a positive point charge with a unit charge and the electron distribution of the molecule. The value of the electrostatic potential also changes depending on the threshold of the electron density. In Table 1, the density threshold in the atomic unit system is set to 0.0004e / a0 3 or 0.003e / a0 3The electrostatic potential in the electron density distribution when

[0107] [Table 1]

[0108] From the above table, the organic compounds represented by the structural formulas (100) to (103) and the structural formula (111) have an electron density distribution threshold of 0.0004e / a0 in the atomic unit system. 3 When this is done, the minimum value of ESP is -0.085E h The organic compounds represented by the structural formulas (100) to (103) and (111) have an electron density distribution threshold of 0.003e / a0 in the atomic unit system. 3 The minimum value of ESP is -0.12E h and it has been found that these are more preferable as the first organic compound.

[0109] This is because the organic compounds represented by structural formulas (100) to (103) and structural formula (111) have electron-donating groups introduced at the 4- and 7-positions of the 1,10-phenanthroline ring, and therefore have high electron-donating properties to the nitrogens at the 1- and 10-positions of the phenanthroline ring.

[0110] The organic compounds represented by the structural formulas (100), (103), and (111) have an electron density distribution threshold of 0.0004e / a0 in the atomic unit system. 3 When this is done, the minimum value of ESP is -0.090E h The organic compounds represented by the structural formulas (103) and (111) have an electron density distribution threshold of 0.003e / a0 in the atomic unit system. 3 When this is done, the minimum ESP value is -0.13E h It has been found that the following is particularly preferable as the first organic compound.

[0111] In addition, the organic compounds represented by the structural formulas (103) and (111) have an electron density distribution threshold of 0.0004e / a0 in the atomic unit system. 3 When this is done, the minimum value of ESP is -0.090E h The threshold of the electron density distribution is 0.003e / a0 3 When this is done, the minimum ESP value is -0.13E h and furthermore, it has been found that these are preferable as the first organic compound.

[0112] In addition, when the first organic compound has a high basicity, it is preferable that the first organic compound has an interaction with holes, thereby significantly reducing the hole transport property in the electron injection layer, and thus a light-emitting device having high efficiency and low driving voltage can be obtained. Specifically, the acid dissociation constant pKa of the first organic compound is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

[0113] If the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa of each skeleton of the organic compound is examined, and the largest acid dissociation constant pKa selected from these can be regarded as the acid dissociation constant pKa of the organic compound.

[0114] Alternatively, the acid dissociation constant may be calculated. For example, the acid dissociation constant pKa can be calculated using the following calculation method.

[0115] The initial molecular structure of each molecule serving as a calculation model is set to the most stable structure (singlet ground state) obtained from first-principles calculations.

[0116] For the above first-principles calculations, Jaguar, a quantum chemistry calculation software made by Schrodinger, is used, and the most stable structure in the singlet ground state is calculated using density functional theory (DFT). 6-31G** is used as the basis function, and B3LYP-D3 is used as the functional. The structure for which the quantum chemistry calculations are performed is sampled by performing conformational analysis using mixed torsional / low-mode sampling using Schrodinger's Maestro GUI.

[0117] In the pKa calculation, one or more atoms of each molecule are designated as basic sites, and a Macro Model is used to search for the stable structure of the protonated molecule in water, and a conformational search is performed using the OPLS2005 force field, and the lowest energy conformer is used. Using the Jaguar pKa calculation module, the structure is optimized with B3LYP / 6-31G*, and then a single-point calculation is performed with cc-pVTZ(+), and the pKa value is calculated using empirical corrections for functional groups. For molecules with one or more atoms designated as basic sites, the largest value among the results obtained is used as the pKa value. The obtained pKa value is shown.

[0118] The acid dissociation constant pKa of 2,9hpp2Phen is 13.35, the acid dissociation constant pKa of 4,7hpp2Phen is 13.42, the acid dissociation constant pKa of Pyrrd-Phen is 11.23, the acid dissociation constant pKa of mPPhen2P is 5.16, the acid dissociation constant pKa of NBPhen is 5.59, and the acid dissociation constant pKa of BPhen is 5.62.

[0119] <Estimation of interactions between metals and organic compounds using quantum chemical calculations> Here, the spin density and electrostatic potential (ESP) when a metal, a first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring, and a second organic compound having a π-electron-deficient heteroaromatic ring interact with each other were analyzed by quantum chemical calculations. The calculations were performed using 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) as the first organic compound, 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) as the second organic compound, and silver (Ag) as the metal.

[0120] Gaussian09 was used as a quantum chemical calculation program. The calculations were performed using an SGI8600 manufactured by HPE. The most stable structures in the ground states of the first organic compound and the second organic compound, the composite material of the first organic compound and a metal, the composite material of the second organic compound and a metal, and the composite material of the first organic compound, the second organic compound and a metal were calculated using density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as the functional. The total energy in DFT is expressed as the sum of the exchange-correlation energy, which includes the potential energy, the electrostatic energy between electrons, the kinetic energy of electrons, and all the complex interactions between electrons. In DFT, the exchange-correlation interaction is approximated by a functional (meaning a function of a function) of a one-electron potential expressed in terms of electron density, so the calculations are highly accurate.

[0121] The analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen) and a metal (Ag), the composite material of the second organic compound (11mDBtBPPnfpr) and a metal (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and a metal (Ag) are shown in Figures 19(A) and 19(B). The spheres in the figures represent the atoms that make up the compounds, and the clouds around the atoms represent the electron density distribution threshold of 0.003e / a0 in the atomic unit system. 3 The figure shows the spin density distribution when the first organic compound (Pyrrd-Phen) and the second organic compound (11mDBtBPPnfpr) are in a singlet ground state, and the localized state of the doublet ground state in the compound is shown. Since the ground state of the first organic compound (Pyrrd-Phen) and the ground state of the second organic compound (11mDBtBPPnfpr) are in a singlet ground state, no spin density distribution is observed.

[0122] In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) to form a composite material. By doing so, as shown in Figure 19 (A), it can be seen that some of the spins derived from the unpaired electrons of the metal (Ag) are distributed to a part of the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), especially the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs. However, because the interaction is weak, most of the spins are distributed to the metal (Ag).

[0123] In addition, in the doublet ground state of the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to form a composite material. By doing so, as shown in Figure 19 (B), it can be seen that a part of the spin derived from the unpaired electron of the metal (Ag) is distributed to a part of the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), especially the nitrogen atom (N) having an unshared electron pair. However, because the interaction is weak, most of the spin is distributed to the metal (Ag).

[0124] On the other hand, in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) according to one embodiment of the present invention, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) interact with each other, and the metal (Ag) is coordinated to the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), thereby stabilizing the composite material. By doing so, as shown in Figure 19(C), it can be seen that the spin originating from the unpaired electron of the metal (Ag) is localized in the second organic compound (11mDBtBPPnfpr). In addition, no spin density distribution is observed in the metal (Ag). From this, it can be seen that the second organic compound (11mDBtBPPnfpr) is in a radical anion state due to the interaction between the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag).

[0125] Next, the analysis results of electrostatic potential maps in the ground state of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), a composite material of the first organic compound (Pyrrd-Phen) and a metal (Ag), a composite material of the second organic compound (11mDBtBPPnfpr) and a metal (Ag), and a composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and a metal (Ag) are shown in Figures 20(A), 20(B), and 21(A) to 21(C). The spheres in the figures represent the atoms that make up the compounds, and the clouds around the atoms represent the electron density distribution threshold of 0.0004e / a0 in the atomic unit system. 3 The electrostatic potential in the electron density distribution when is expressed as follows. The electrostatic potential is the interaction energy between a positive point charge with unit electric charge and the electron distribution of the molecule, and the electrostatic potential map represents the electrostatic potential in the isoelectron density surface with colors, with regions with negative electrostatic potential represented in red and regions with positive electrostatic potential represented in blue, indicating that atoms in regions with negative electrostatic potential have negative charges and atoms in regions with positive electrostatic potential have positive charges. However, since Figures 20 and 21 are grayscale images, in order to indicate regions with negative electrostatic potential and regions with positive electrostatic potential, the dark red parts (i.e., regions with negative electrostatic potential) are surrounded by thick dotted lines and the dark blue parts (i.e., regions with positive electrostatic potential) are surrounded by thin dashed lines.

[0126] As shown in FIG. 20(A), in the singlet ground state of the first organic compound (Pyrrd-Phen), it can be seen that the electrostatic potential around the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs in the 1,10-phenanthroline ring is negative. In addition, the Mulliken partial charge of the N atom is negative, at -0.29e in atomic units. From these facts, it can be seen that the N atom has a negative partial charge.

[0127] In addition, as shown in FIG. 20(B), in the singlet ground state of the second organic compound (11mDBtBPPnfpr), it can be seen that the electrostatic potential around the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring is negative. In addition, the Mulliken partial charge of the N atom was negative at -0.31e in atomic units. From these, it can be seen that the N atom has a negative partial charge.

[0128] In addition, in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), forming a composite material. As a result, as shown in FIG. 21(A), it can be seen that the electrostatic potential around the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the metal (Ag) is negative. In addition, the Mulliken partial charge of the N atom is -0.37e in atomic units, and the Mulliken partial charge of the metal (Ag) is -0.18e in atomic units, which are negative. From these facts, it is found that the N atom and the Ag atom have a negative partial charge.

[0129] In addition, in the doublet ground state of the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to form a composite material. As a result, as shown in Figure 21 (B), it can be seen that the electrostatic potential around the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is negative. In addition, the Mulliken partial charge of the N atom is -0.38e in atomic units, and the Mulliken partial charge of the metal (Ag) is -0.09e in atomic units, which is negative. From these, it can be seen that the N atom and the Ag atom have negative partial charges.

[0130] On the other hand, in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) according to one embodiment of the present invention, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) interact with each other, and the metal (Ag) is coordinated to the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), thereby stabilizing the composite material. As a result, as shown in FIG. 21(C), it can be seen that the positive electrostatic potential is mainly distributed in the metal (Ag) and the first organic compound (Pyrrd-Phen), and the negative electrostatic potential is mainly distributed in the second organic compound (11mDBtBPPnfpr). It can also be seen that the electrostatic potential around the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative, while the electrostatic potential around the metal (Ag) is positive. In addition, the Mulliken partial charge of the N atom is negative at -0.62e in atomic units, while the Mulliken partial charge of the metal (Ag) is positive at 0.37e in atomic units. From these, it can be seen that the charge of the Ag atom is distributed to the N atom.

[0131] From the above, it is understood that this combination forms a donor level by interaction between a first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring and a metal, and further functions as an electron donor for a second organic compound having a π-electron-deficient heteroaromatic ring. In one embodiment of the present invention, by using this combination of materials for an electron injection layer, it is possible to form an electron injection layer that has good electron injection properties and is resistant to oxygen and water in the air, as well as water and chemicals used in the process of a lithography method, and therefore it is possible to obtain a light-emitting device with reduced driving voltage and high luminous efficiency.

[0132] <Estimation of SOMO or HOMO levels in the interaction between metals and organic compounds by quantum chemical calculations> Next, we used quantum chemical calculations to estimate the stabilization energy when a metal, a first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring, and a second organic compound having a π-electron-deficient heteroaromatic ring interact, as well as the SOMO level or HOMO level formed at that time.

[0133] Gaussian09 was used as a quantum chemical calculation program. The calculation was performed using an SGI8600 manufactured by HPE. First, the most stable structures in the ground states of the first organic compound, the second organic compound, and the metal, and the composite material of the first organic compound and the metal, the composite material of the second organic compound and the metal, and the composite material of the first organic compound, the second organic compound, and the metal were calculated using density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as functional. Next, the stabilization energy was calculated from the difference between the total energy of the composite material of the organic compound and the metal and the sum of the total energy of the organic compound alone and the total energy of the metal alone. In other words, (stabilization energy) = (total energy of the composite material of the organic compound and the metal) - (total energy of the organic compound alone) - (total energy of the metal alone).

[0134] The first organic compound was 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen), and the second organic compounds were 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzo The results of calculations of furo[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), and 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn) using indium (In) as the metal are shown in the table below. Note that the energy levels of the HOMO and SOMO in the table are calculated values ​​and may differ from the actual measurements.

[0135] [Table 2]

[0136] [Table 3]

[0137] [Table 4]

[0138] From the above table, the stabilization energy of the composite material consisting of two materials, a metal (In) and a second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), was a negative value. This indicates that when the organic compound is mixed with a metal, the organic compound interacting with the metal is more energetically stable than the organic compound not interacting with the metal. In addition, the SOMO levels formed at this time are all higher than the HOMO levels of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn).

[0139] In addition, a composite material of a second organic compound (NBPhen) having the same 1,10-phenanthroline ring as the π-electron-deficient heteroaromatic ring as the first organic compound Pyrrd-Phen, and a metal (In), has a larger absolute value of stabilization energy and is more stable than composite materials of a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-electron-deficient heteroaromatic ring different from the 1,10-phenanthroline ring and a metal (In), and also forms a higher SOMO level.

[0140] Here, it can be seen that a composite material made of three materials, namely, a metal (In) according to one embodiment of the present invention, a first organic compound (Pyrrd-Phen), and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), has a larger absolute value of stabilization energy and is more stable than a composite material made of two materials, namely, a metal (In) and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn). In addition, the SOMO level formed at this time is higher than the HOMO levels of the first organic compound (Pyrrd-Phen) and the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn). A high SOMO level is preferable because it has excellent electron injection properties.

[0141] In this case, the composite of the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-electron-deficient heteroaromatic ring different from the 1,10-phenanthroline ring of the first organic compound Pyrrd-Phen, the first organic compound (Pyrrd-Phen), and a metal (In) has a larger absolute value of stabilization energy and is more stable than the composite of the second organic compound (NBPhen) having the same 1,10-phenanthroline ring as Pyrrd-Phen as a π-electron-deficient heteroaromatic ring, the first organic compound (Pyrrd-Phen), and a metal (In), and the SOMO level formed is also higher.

[0142] In this manner, when an organic compound having a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound), and a metal interact to form a composite material, it is preferable that the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different rings, because this provides superior stability and electron injection properties.

[0143] As shown in the above table, the stabilization energy of the composite material of the metal, the first organic compound, and the second organic compound is preferably large in absolute value and more stable. The SOMO level formed in this case is higher than the HOMO levels of the first organic compound and the second organic compound. A high SOMO level is preferable because it has excellent electron injection properties. In addition, a high SOMO level can be formed even if a metal that is stable in the air, such as silver or indium, is used without using an alkali metal compound, so that an electron injection layer with excellent stability and electron injection properties can be formed.

[0144] <Second organic compound> The electron injection layer contains a second organic compound containing a π-electron-deficient heteroaromatic ring in addition to a metal or metal oxide and a first organic compound. By containing the second organic compound, it is possible to improve heat resistance and electron transport properties. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring of the first organic compound is the first π-electron-deficient heteroaromatic ring and the π-electron-deficient heteroaromatic ring of the second organic compound is the second π-electron-deficient heteroaromatic ring, it is preferable that the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different rings.

[0145] Furthermore, as the second π-electron-deficient heteroaromatic ring, 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, or a heteroaromatic ring having a triazine skeleton is preferred, with a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring being particularly preferred due to their electrochemical stability and high electron transport property.

[0146] The second π-electron-deficient heteroaromatic ring may have a condensed ring structure.

[0147] In one embodiment of the present invention, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound and is preferably at least 0.80 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound. It is more preferable that the LUMO level is not more than 0.25 eV lower than the LUMO level of the first organic compound, more preferably that the LUMO level is at least 0.50 eV lower than the LUMO level of the first organic compound and not more than 0.30 eV lower than the LUMO level of the first organic compound, more preferably that the LUMO level is at least 0.50 eV lower than the LUMO level of the first organic compound and not more than 0.35 eV lower than the LUMO level of the first organic compound, and more preferably that the LUMO level is at least 0.50 eV lower than the LUMO level of the first organic compound and not more than 0.40 eV lower than the LUMO level of the first organic compound.

[0148] That is, assuming that the LUMO level of the first organic compound is "LUMO1 (eV)" and the LUMO level of the second organic compound is "LUMO2 (eV)", it is preferable that LUMO2 satisfies the following formula (1). LUMO1-0.80≦LUMO2≦LUMO1-0.20 Formula (1)

[0149] It is more preferable that LUMO2 satisfies the following formula (2). LUMO1-0.50≦LUMO2≦LUMO1-0.20 Formula (2)

[0150] It is more preferable that LUMO2 satisfies the following formula (3). LUMO1-0.50≦LUMO2≦LUMO1-0.25 Formula (3)

[0151] It is more preferable that LUMO2 satisfies the following formula (4). LUMO1-0.50≦LUMO2≦LUMO1-0.30 Formula (4)

[0152] It is more preferable that LUMO2 satisfies the following formula (5). LUMO1-0.50≦LUMO2≦LUMO1-0.35 Formula (5)

[0153] It is more preferable that LUMO2 satisfies the following formula (6). LUMO1-0.50≦LUMO2≦LUMO1-0.40 Formula (6)

[0154] When LUMO2 is in the above range, the light-emitting device according to one embodiment of the present invention can have favorable characteristics such as a low driving voltage, regardless of whether or not it is subjected to a photolithography process involving exposure of the EL layer to the atmosphere, and can also have favorable reliability.

[0155] The second organic compound may be an organic compound having an electron transporting property. The organic compound having an electron transporting property may be an organic compound having an electron mobility of 1×10 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 A substance having an electron mobility of 1 / Vs or more is preferable. Note that other substances can also be used as long as they have a higher electron transporting property than a hole transporting property.

[0156] Specific examples of organic compounds having electron transport properties include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 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-carbodiazole (abbreviation: OXD-7), and 1,2,4-diphenyl-2-phenyl-1,2,4-triazole (abbreviation: OXD-7). Bazol (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 4,7 -Diphenyl-2,9-bis[4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl]-1,10-phenanthroline (abbreviation: DBimiBphen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl) )biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 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), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 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), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)] Bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[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), 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl- 4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3- b]pyrazine (abbreviation: 11mDBtBPPnfpr), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6 -diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-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-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-Diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridine-3 -yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP- Icz(II)Tzn), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-di Examples of organic compounds having a triazine skeleton include benzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn), and 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz).

[0157] Among the above, ZADN, mSiTrz, mPn-mDMePyPTzn, 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr, and βNP-SFx(4)Tzn are preferable as the second organic compound because they have appropriate LUMO levels. By using these organic compounds, it becomes easy to obtain a light-emitting device with good characteristics in which an increase in driving voltage is suppressed even in a light-emitting device that has undergone a process involving exposure of the EL layer to the atmosphere.

[0158] The carbon number of the second organic compound is preferably from 25 to 100. By setting the carbon number in this range, an organic compound with excellent sublimability can be obtained, so that thermal decomposition of the organic compound can be suppressed during vacuum deposition, and good material usage efficiency can be obtained.

[0159] In addition, it is preferable to use an organic compound having a glass transition temperature Tg of 100° C. or higher as the second organic compound. This makes it possible to make the electron injection layer a layer that has good heat resistance and is difficult to crystallize, and therefore, makes it possible to make the layer difficult to crystallize even when a part of the EL layer is processed by a lithography method.

[0160] In addition, the second organic compound can be an organic compound having an acid dissociation constant pKa of less than 4. This can reduce the solubility of the second organic compound in water, thereby increasing the resistance to water and chemicals used in the lithography process.

[0161] Compared with the solubility in water of an organic compound having an acid dissociation constant pKa of 4 or more, the solubility in water of an organic compound having an acid dissociation constant pKa smaller than 4 is low. In addition, compared with the case where an organic compound having an acid dissociation constant pKa of 4 or more is used as the second organic compound, the water resistance of the electron injection layer can be improved by using an organic compound having an acid dissociation constant pKa smaller than 4 as the second organic compound. In addition, the occurrence of defects such as the electron injection layer peeling off from other layers during the manufacturing process can be suppressed. This makes it possible to suppress the occurrence of defects that cause defects in the light-emitting device.

[0162] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn, and the like can be suitably used as the second organic compound.

[0163] The acid dissociation constant pKa of 4,8mDBtP2Bfpm is 0.60. The acid dissociation constant pKa of 11mDBtBPPnfpr is -1.85. If the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa of each skeleton of the organic compound can be examined, and the largest acid dissociation constant pKa selected from these can be regarded as the acid dissociation constant pKa of the organic compound.

[0164] For example, the solubility parameter δ is 4.0 MPa. 0.5 An organic compound having the following polarization term δp can be used as the second organic compound. For example, a solubility parameter δ of 4.0 MPa 0.5 4.0MPa, compared with the solubility in water of organic compounds with a larger polarization term δp. 0.5 Organic compounds with a polarization term δp below 4.0MPa have low solubility in water. 0.5 4.0MPa compared to when an organic compound having a larger polarization term δp is used as the second organic compound. 0.5 By using an organic compound having the following polarization term δp as the second organic compound, the water resistance of the electron injection layer can be improved. In addition, the occurrence of defects such as the electron injection layer peeling off from other layers during the photolithography process can be suppressed. This makes it possible to suppress the occurrence of defects that cause defects in the light-emitting device.

[0165] The polarization term δp of the solubility parameter δ of water is 16.0MPa. 0.5 This is described in JP 2017-173056 A.

[0166] The greater the difference between the polarization term δp of the solubility parameter δ and the polarization term δp of the solvent water, the lower the solubility in water and the more preferable it is. 0.5 It is preferable to use an organic compound having the following polarization term δp as the second organic compound.

[0167] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, and BP-BPIcz(II)Tzn can be suitably used as the second organic compound.

[0168] The polarization term δp of the solubility parameter δ of 8BP-4mDBtPBfpm is 3.5MPa. 0.5 The polarization term δp of the solubility parameter δ of 4,8mDBtP2Bfpm is 3.4MPa. 0.5 The polarization term δp of the solubility parameter δ of 6BP-4Cz2PPm is 3.4MPa. 0.5 The polarization term δp of the solubility parameter δ of 2mDBTBPDBq-II is 3.2MPa. 0.5 The polarization term δp of the solubility parameter δ of 9mDBtBPNfpr is 3.8MPa. 0.5 The polarization term δp of the solubility parameter δ of 11mDBtBPPnfpr is 3.1MPa. 0.5 The polarization term δp of the solubility parameter δ of mPCCzPTzn-02 is 3.5MPa. 0.5 The polarization term δp of the solubility parameter δ of BP-BPIcz(II)Tzn is 3.2MPa. 0.5 It is.

[0169] The polarization term δp of the solubility parameter δ was calculated using the following calculation method.

[0170] The classical molecular dynamics calculation software used was Desmond manufactured by Schrodinger. The force field used was OPLS2005. The calculations were performed using Apollo6500 manufactured by HPE.

[0171] A reference cell with about 32 molecules was used for the calculation model. The initial molecular structure of each compound was a mixture of the most stable structure (singlet ground state) obtained from first-principles calculations and multiple structures with energy close to the most stable structure in equal ratios, and the molecules were randomly arranged to prevent collisions. After that, the structures were randomly moved and rotated by Monte Carlo simulated annealing using OPLS2005 as the force field to move the molecules. Furthermore, the molecules were moved toward the center of the reference cell to maximize the density, and the initial arrangement was created.

[0172] For the above first-principles calculations, quantum chemistry calculation software Jaguar was used, and the most stable structure in the singlet ground state was calculated using density functional theory (DFT). 6-31G** was used as the basis function, and B3LYP-D3 was used as the functional. The structure for which the quantum chemistry calculations were performed was sampled by performing conformational analysis using mixed torsional / low-mode sampling using Schrodinger's Maestro GUI. The calculations were performed using HPE's Apollo 6500.

[0173] The above initial configuration was subjected to Brownian motion simulation, followed by NVT ensemble, and then calculation was performed with sufficient relaxation time (30 ns) for the step time (2 fs) to reproduce molecular vibrations under the condition of 1 atm and 300 K to calculate the amorphous solid. The solubility parameter δ of the obtained amorphous solid is defined by the following equation.

[0174]

number

[0175] Here, ΔHv represents the heat of vaporization, which is the energy of the reference cell minus the total energy of each molecule averaged over the entire molecular dynamics calculation, Vm represents the molar volume, R represents the gas constant, and T represents the temperature. Note that the solubility parameter shows a tendency for the solubility to decrease as the difference between the solvent substance and the solute substance increases.

[0176] The solubility parameter δ can be decomposed into a dispersion term δd and a polarization term δp. The dispersion term δd is a term contributed by van der Waals interactions, and the polarization term δp is a term contributed by electrostatic interactions. In particular, the solubility of a solute in water is greatly contributed by the electrostatic interactions that occur between the dipoles of the solute and water molecules. In fact, the solubility in water of organic compounds that can be used for the second organic compound shows a good correlation with the polarization term δp of the solubility parameter δ obtained by calculation.

[0177] It is more preferable that the LUMO level of the second organic compound is lower than that of the first organic compound. This makes it easier for the donor level formed by the first organic compound and the metal or metal oxide to donate electrons to the second organic compound. It is also preferable that the second organic compound has electron transport properties, and for this reason, it is also preferable that the LUMO level of the second organic compound is lower than that of the first organic compound.

[0178] The second organic compound has a LUMO level of preferably -3.0 eV to -2.0 eV, more preferably -3.0 eV to -2.5 eV, and the first organic compound has a LUMO level of preferably -3.0 eV to -2.0 eV, more preferably -2.7 eV to -2.0 eV.

[0179] This makes it easier for the first organic compound to donate electrons to the second organic compound from the donor level formed by the first organic compound and the metal or metal oxide, and also makes it easier for the second organic compound to transport electrons.

[0180] Furthermore, in the electron injection layer, by including a second organic compound in addition to a metal or metal oxide and a first organic compound, interaction between the materials occurs efficiently. This can be confirmed by measuring the spin density using electron spin resonance (ESR).

[0181] For example, the spin density measured by ESR of a film containing a metal or metal oxide and a first organic compound is preferably higher than the spin density measured by ESR of a film containing a metal or metal oxide and a second organic compound.Also, the spin density measured by ESR of a film containing a metal or metal oxide, a first organic compound, and a second organic compound is preferably higher than the spin density measured by ESR of a film having only two materials, either a metal or metal oxide, a first organic compound, or a second organic compound, and in this case, it can be confirmed that the interaction between the materials occurs efficiently.

[0182] More specifically, the film containing a metal or metal oxide and a first organic compound has a spin density of 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3 or more is preferable. In such a case, it can be confirmed that an interaction between materials occurs efficiently in a layer having a combination of a metal or metal oxide and a first organic compound. Alternatively, a film containing a metal or metal oxide, a first organic compound, and a second organic compound has a spin density resulting from a signal observed in the vicinity of a g value of 2.00 by an electron spin resonance method of, for example, 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3or more is preferable. In such a case, it can be confirmed that in a layer having a combination of a metal or metal oxide, a first organic compound, and a second organic compound, the interaction between the materials occurs more efficiently than in a layer having only two of these materials. In this case, for a mixed film containing a metal or metal oxide and a second organic compound, the spin density resulting from a signal observed in the vicinity of a g value of 2.00 by electron spin resonance is, for example, 2×10 16 spins / cm 3 For a mixed film containing the first organic compound and the second organic compound, the spin density due to a signal observed in the vicinity of a g value of 2.00 by an electron spin resonance method is 2×10 16 spins / cm 3 The following is the result.

[0183] In the electron injection layer, the molar ratio of the metal or metal oxide to the first organic compound (or the total of the first organic compound and the second organic compound) is preferably 0.1 to 10, more preferably 0.2 to 5, and even more preferably 0.5 to 2. Alternatively, the volume ratio is preferably 0.01 to 0.3, more preferably 0.02 to 0.2, and even more preferably 0.05 to 0.1. By including the metal or metal oxide and the first organic compound (or the first organic compound and the second organic compound) in such a ratio, an electron injection layer having good electron injection properties can be provided. In addition, the second organic compound does not have to be used, but when the second organic compound is used, the ratio of the first organic compound to the second organic compound is preferably 0.1 to 10, more preferably 0.2 to 5, and even more preferably 0.5 to 2, in terms of volume ratio. By mixing the first organic compound and the second organic compound in such a ratio, an electron injection layer having good electron transport properties can be provided. In addition, by using an organic compound having high Tg and good thermal properties as the second organic compound, it is possible to provide an organic EL device having good reliability.

[0184] The thickness of the electron injection layer is preferably 2 nm to 20 nm, more preferably 5 nm to 10 nm. When the electron injection layer has a laminated structure of a metal layer and a layer containing a first organic compound, the thickness of the metal layer is preferably 0.1 nm to 5 nm, more preferably 0.2 nm to 2 nm. When the electron injection layer has a laminated structure of a metal layer and a layer containing a first organic compound, the thickness of the layer containing the first organic compound is preferably 2 nm to 20 nm, more preferably 5 nm to 10 nm.

[0185] A light-emitting device of one embodiment of the present invention having the above-described structure can be a light-emitting device with good characteristics even when subjected to processing by a photolithography method involving exposure to the air or exposure to the air before the formation of the second electrode.

[0186] Furthermore, a light-emitting device according to one embodiment of the present invention having the above structure can have high current efficiency and high reliability in which an increase in driving voltage is suppressed.

[0187] Note that the light-emitting device of one embodiment of the present invention is particularly suitable for a light-emitting device that has undergone a photolithography process; however, even a light-emitting device manufactured without undergoing a photolithography process has high stability against the atmosphere, which improves yield and contributes to cost reduction because it is not necessary to control the atmosphere more strictly during the manufacturing process.

[0188] (Embodiment 2) In this embodiment, a light-emitting device according to one embodiment of the present invention will be described in detail.

[0189] 1 is a schematic diagram of a light-emitting device according to one embodiment of the present invention. The light-emitting device has a first electrode 101 provided over an insulator 100, and has an EL layer 103 between the first electrode 101 and a second electrode 102. The EL layer 103 has at least a light-emitting layer 113 and an electron injection layer 115. The light-emitting layer 113 is a layer containing a light-emitting substance, and emits light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0190] 1(A), the EL layer 103 preferably has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 114 in addition to the light emitting layer 113 and the electron injection layer 115. The EL layer 103 may also include functional layers other than those described above, such as a hole blocking layer, an exciton blocking layer, and an intermediate layer. Conversely, any of the layers described above may not be provided.

[0191] The electron injection layer 115 is a layer containing an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, as described in Embodiment 1. The electron injection layer 115 may further contain another organic compound (third organic compound).

[0192] The specific configuration of the electron injection layer 115 has been described in detail in the first embodiment, and therefore a repeated description will be omitted.

[0193] In the present embodiment, the first electrode 101 is an electrode including an anode, the second electrode 102 is an electrode including a cathode, and an example has been shown in which the first electrode 101 is formed on the insulator 100 side, but the second electrode 102 may be formed on the insulator 100 side, that is, a so-called inverted stack structure. In this case, the light-emitting device has a laminated structure in which, from the insulator 100 side, the second electrode 102, the electron injection layer 115, (the electron transport layer 114), the light-emitting layer 113, (the hole transport layer 112, the hole injection layer 111, and) the first electrode 101 are stacked in this order. In the case of such a light-emitting device with an inverted stack structure, the relatively stable hole injection layer 111 is on the surface, so that the light-emitting device can have better reliability.

[0194] In addition, the first electrode 101 and the second electrode 102 may be formed as a single layer structure or a laminated structure, and in the case of a laminated structure, a layer in contact with the EL layer 103 functions as an anode or a cathode. In the case of an electrode having a laminated structure, there is no restriction on the work function of layers other than the layer in contact with the EL layer 103, and materials can be selected according to required characteristics such as resistance value, ease of processing, reflectance, light transmittance, and stability.

[0195] 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). Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide (ITSO), indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metals or oxide films thereof are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like. As an example of a method for forming indium oxide-zinc oxide, a method for forming indium oxide-zinc oxide by a sputtering method using a target in which 1 to 20 wt % of zinc oxide is added to indium oxide may be used. Indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials used for the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), or nitrides of metal materials (for example, titanium nitride). A layer of these laminated materials may also be used as the anode. For example, a film laminated in the order of Al, Ti, and ITSO on Ti is preferable because it has a good reflectance, is highly efficient, and can achieve high resolution of several thousand ppi. Alternatively, graphene can also be used as a material used for the anode. In addition, by using a composite material capable of forming the hole injection layer 111 described later as a layer in contact with the anode (typically a hole injection layer), it becomes possible to select an electrode material regardless of the work function.

[0196] The hole injection layer 111 is provided in contact with the anode and has a function of facilitating the injection of holes into the EL layer 103. The hole injection layer 111 can be formed of a phthalocyanine-based compound or complex compound such as phthalocyanine (abbreviation: HPc) or copper phthalocyanine (abbreviation: CuPc), an aromatic amine compound such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) or 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / (polystyrenesulfonic acid) (abbreviation: PEDOT / PSS).

[0197] The hole injection layer 111 may be formed of a substance having electron acceptor properties. As the substance having electron acceptor properties, an organic compound having an electron-withdrawing group (such as a halogen group or a cyano group) can be used, and examples of the substance include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and preferred. Radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group, a cyano group, etc.) [3] are preferred because they have a very high electron-accepting property, and specific examples thereof include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. As the substance having electron acceptor properties, in addition to the organic compounds described above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used.

[0198] In addition, the hole-injection layer 111 is preferably formed using a composite material containing the above-mentioned material having an electron acceptor property and an organic compound having a hole-transport property.

[0199] As the organic compound having a hole transporting property used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that the organic compound having a hole transporting property used in the composite material is preferably 1×10 -6 cm 2 It is preferable that the organic compound has a hole mobility of 1000 nm or more / Vs. The organic compound having hole transport properties used in the composite material is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferable. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton in the ring is preferable, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed to the above rings is preferable.

[0200] In addition, in a composite material containing the above-mentioned material having electron acceptor properties and an organic compound having hole transport properties, the interaction between the materials occurs efficiently. Therefore, the spin density of a film containing the composite material measured by electron spin resonance (ESR) is 1×10 due to a signal observed near a g value of 2.00. 17 spins / cm 3 The above is preferred.

[0201] Such organic compounds having hole transport properties preferably have any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the organic compounds may be aromatic amines having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the organic compounds having hole transport properties are substances having an N,N-bis(4-biphenyl)amino group, because this allows the manufacture of a light-emitting device with a long life.

[0202] Specific examples of organic compounds having hole transport properties as described above 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)benzylamine (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(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-4-amino-p-terphenyl ]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβ NB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl] 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N- Bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4' -[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'- Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-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. can be mentioned.

[0203] In addition, as a material having hole transport properties, other aromatic amine compounds such as 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), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) can also be used.

[0204] By forming the hole injection layer 111, the hole injection property is improved, and a light emitting device with a low driving voltage can be obtained.

[0205] Among substances having electron acceptor properties, organic compounds having electron acceptor properties are easy to use because they can be easily evaporated and formed into a film.

[0206] The hole transport layer 112 is formed by including an organic compound having a hole transport property. -6 cm 2 It is preferable that the hole mobility is 1 / Vs or more.

[0207] Examples of the material having the hole transporting property include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'- (9-Phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), Compounds with aromatic amine skeletons such as 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)phenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and 4,4'-di(N-carbazolyl)phenylamine (abbreviation: PCBASF) bazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-Bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation :BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"- terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylene-2 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compounds include compounds having a thiophene skeleton such as 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)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Note that the substances exemplified as the materials having hole transport properties used for the composite material of the hole injection layer 111 can also be suitably used as the material for forming the hole transport layer 112.

[0208] The light-emitting layer 113 is a layer containing a light-emitting substance, and preferably contains a light-emitting substance and a host material. The light-emitting layer 113 may contain other materials at the same time. The light-emitting layer 113 may also be a laminate of two layers with different compositions.

[0209] The luminescent material may be a fluorescent material, a phosphorescent material, a material exhibiting thermally activated delayed fluorescence (TADF), or any other luminescent material.

[0210] Examples of materials that can be used as the fluorescent substance in the light-emitting layer include the following: In addition, fluorescent substances other than these can also be used.

[0211] 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 (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N'''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA) , 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyrazol-2-yl)-1,1-diphenylquinacridone (abbreviation: DPQd), DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB),6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphthalene] N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, condensed aromatic diamine compounds such as pyrene diamine compounds, such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they have high hole trapping properties and excellent luminous efficiency or reliability.

[0212] In addition, 5,9-diphenyl-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: DABNA3), Amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: Me-tBu4DABNA), N 7 ,N 7 ,N 13 ,N 13 Condensed heteroaromatic compounds containing nitrogen and boron, such as 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazaborine-7,13-diamine (abbreviation: ν-DABNA) and 2-(4-tert-butylphenyl)benz[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc), in particular compounds having a diaza-boranaphtho-anthracene skeleton, can be suitably used because they have a narrow emission spectrum and can emit blue light with good color purity.

[0213] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-Y) and the like can be preferably used.

[0214] When a phosphorescent material is used as the light-emitting material in the light-emitting layer, examples of materials that can be used include the following.

[0215] Organometallic iridium compounds with 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) (abbreviation: [Ir(mpptz-dmp)3]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]). complexes, organometallic iridium complexes with 1H-triazole skeletons such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), fac-tris[1-( 2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN3} organometallic iridium complexes with an imidazole skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), and organometallic complexes with a benzimidazolidene skeleton, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ] Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as FIracac), are examples of such compounds that exhibit blue phosphorescence and have a peak emission wavelength in the range of 450 nm to 520 nm.

[0216] In addition, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6- Organometallic iridium complexes having a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]) and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]); organometallic iridium complexes having a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]); 2’) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’)iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3- Methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl In addition to organometallic iridium complexes having a pyridine skeleton such as [2-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mdppy)]), rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]) can be mentioned. These are compounds that mainly exhibit green phosphorescence and have emission peaks in the wavelength range of 500 nm to 600 nm. Note that organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0217] In addition, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]); Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinate)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinate)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’Organometallic iridium compounds with pyridine skeletons such as (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III) and (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). In addition to iridium complexes, platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]) are examples of rare earth metal complexes. These are compounds that exhibit red phosphorescence and have a peak emission in the wavelength range from 600 nm to 700 nm. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity.

[0218] In addition to the above-mentioned phosphorescent compounds, known phosphorescent compounds may be selected and used.

[0219] TADF materials include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also included are metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. Examples of the metal-containing porphyrin include 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)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP), which are shown in the following structural formulas.

[0220] [ka]

[0221] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), Heterocyclic compounds having one or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 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-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and the triazine skeleton are preferred because they are stable and reliable. In particular, the benzofuropyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuropyrazine skeleton, and the benzothienopyrazine skeleton are preferred because they have high electron acceptor properties and good reliability. In addition, among the skeletons having a π-electron rich heteroaromatic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton, and the pyrrole skeleton are preferred because they are stable and reliable.In addition, the furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. In addition, the pyrrole skeleton is particularly preferably an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because 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 strong, and the energy difference between the S1 level and the T1 level is small, so that thermally activated delayed fluorescence can be efficiently obtained. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. In addition, an aromatic amine skeleton, a phenazine skeleton, or the like can be used as the π-electron-rich skeleton. In addition, examples of the π-electron-deficient skeleton that can be used include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0222] [ka]

[0223] TADF materials are materials that have a small difference between the S1 and T1 levels and have the function of converting triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy by a small amount of thermal energy (reverse intersystem crossing), and singlet excitation states can be generated efficiently. In addition, triplet excitation energy can be converted into light emission.

[0224] In addition, exciplexes (also called exciplexes), which form an excited state with two types of substances, have an extremely small difference between the S1 level and the T1 level and function as TADF materials that can convert triplet excitation energy into singlet excitation energy.

[0225] As an index of the T1 level, a phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K) may be used. For a TADF material, when a tangent line is drawn at the base of the short wavelength side of the fluorescence spectrum, and the energy of the wavelength of the extrapolated line is defined as the S1 level, and a tangent line is drawn at the base of the short wavelength side of the phosphorescence spectrum, and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between the S1 level and the T1 level is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0226] In addition, when a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0227] As the host material of the light-emitting layer, various carrier transporting materials such as a material having an electron transporting property and / or a material having a hole transporting property, or the above-mentioned TADF material can be used.

[0228] As the material having hole transport properties, an organic compound having an amine skeleton, a π-electron-rich heteroaromatic ring skeleton, etc. is preferable. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton in the ring is preferable, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed to the above is preferable.

[0229] Such organic compounds having hole transport properties preferably have any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the organic compounds may be aromatic amines having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the organic compounds having hole transport properties are substances having an N,N-bis(4-biphenyl)amino group, because this allows the manufacture of a light-emitting device with a long life.

[0230] Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 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 PC Aromatic amines such as 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF) Compounds with a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compounds include compounds having a thiophene skeleton such as 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)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. In addition, the organic compounds listed as examples of materials having hole transportability in the hole transport layer can also be used.

[0231] Examples of materials having electron transport properties include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring having an azole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0232] Among them, organic compounds containing a heteroaromatic ring having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferable because of their good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. In addition, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, and benzothienopyrazine skeleton are preferable because of their high electron acceptor properties and good reliability.

[0233] Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole- Organic compounds with an azole skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), )phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10 -phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: PnNPhen), 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), and other organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), 2-[4'-(9-phenyl 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 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) ), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mD BTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[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), 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzfuro[3,2-d]pyrimidine 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalene-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz) Organic compounds with a diazine skeleton, 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-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-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl -1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpB PTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,Examples of the organic compounds include organic compounds containing a heteroaromatic ring having a triazine skeleton, such as 5-triazine (abbreviation: βNP-SFx(4)Tzn) and 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz). In addition, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred because of their high reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0234] As a TADF material that can be used as a host material, the same TADF materials listed above can be used. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy by reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby increasing the light-emitting efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0235] This is very effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0236] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest energy absorption band of the fluorescent material, because this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0237] In addition, in order to efficiently generate singlet excitation energy from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. In addition, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. For this purpose, it is preferable that the fluorescent material has a protective group around the luminophore (skeleton causing light emission) of the fluorescent material. As the protective group, a substituent having no π bond is preferable, and a saturated hydrocarbon is preferable, specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms are mentioned, and it is more preferable that there are a plurality of protective groups. Since a substituent having no π bond has poor function of transporting carriers, the distance between the TADF material and the luminophore of the fluorescent material can be increased without affecting carrier transport or carrier recombination. Here, the luminophore refers to an atomic group (skeleton) causing light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such 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, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton are preferred because they have a high fluorescence quantum yield.

[0238] When a fluorescent emitting material is used as the emitting material, a material having an anthracene skeleton is suitable as the host material. When a material having an anthracene skeleton is used as the host material of the fluorescent emitting material, it is possible to realize an emitting layer having both good luminous efficiency and durability. As a material having an anthracene skeleton to be used as the host material, a material having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferable because it is chemically stable. In addition, when the host material has a carbazole skeleton, it is preferable because the hole injection and transport properties are increased, but when the host material contains a benzocarbazole skeleton in which a benzene ring is further condensed to carbazole, the HOMO level is about 0.1 eV higher than when the host material contains a carbazole skeleton, making it easier for holes to enter, and is more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, it is preferable because the HOMO level is about 0.1 eV higher than when the host material contains a carbazole skeleton, making it easier for holes to enter, and also because it has excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). From the viewpoint of the hole injection / transport property, 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 (abbreviation: PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'- 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo Zo[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), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices because they show very good properties.

[0239] The host material may be a mixture of a plurality of substances, and when a mixture of host materials is used, it is preferable to mix a material having an electron transporting property with a material having a hole transporting property. By mixing a material having an electron transporting property with a material having a hole transporting property, the transporting property of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The weight ratio of the content of the material having a hole transporting property to the material having an electron transporting property (material having a hole transporting property:material having an electron transporting property) can be 1:19 to 19:1.

[0240] A phosphorescent material can be used as a part of the mixed material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as a light-emitting material.

[0241] In addition, these mixed materials may form an exciplex. It is preferable to select a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest energy absorption band of the light-emitting material, because this makes energy transfer smooth and allows efficient light emission. In addition, the use of this structure is preferable because the driving voltage is reduced.

[0242] At least one of the materials forming the exciplex may be a phosphorescent material, which allows the triplet excitation energy to be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0243] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transport properties is equal to or higher than the HOMO level of the material having electron transport properties. It is also preferable that the LUMO level of the material having hole transport properties is equal to or higher than the LUMO level of the material having electron transport properties. The LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0244] The formation of an exciplex can be confirmed, for example, by comparing the emission spectrum of a material having hole transport properties, the emission spectrum of a material having electron transport properties, and the emission spectrum of a mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectrum of each material (or has a new peak on the longer wavelength side). Alternatively, the formation of an exciplex can be confirmed 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 obtained by mixing these materials, and observing the difference in transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component than the transient PL lifetime of each material, or the proportion of delayed components becoming larger. The above-mentioned transient PL may also be read as transient electroluminescence (EL). That is, the formation of an exciplex can also be confirmed 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 obtained by mixing these materials, and observing the difference in transient response.

[0245] The electron transport layer 114 is a layer containing a substance having an electron transport property. The material having an electron transport property is a material having an electron mobility of 1×10 -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 A substance having an electron mobility of 100 / Vs or more is preferable. Note that, other substances can be used as long as they have a higher transportability of electrons than holes. Note that, as the organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferable. As the organic compound having a π-electron-deficient heteroaromatic ring, for example, it is preferable to use one or more of an organic compound having a heteroaromatic ring with an azole skeleton, an organic compound having a heteroaromatic ring with a pyridine skeleton, an organic compound having a heteroaromatic ring with a diazine skeleton, and an organic compound having a heteroaromatic ring with a triazine skeleton.

[0246] As the organic compound having electron transport properties that can be used in the electron transport layer 114, the organic compound having electron transport properties in the light emitting layer 113 and the organic compound listed as the organic compound that can be used as the second organic compound of the electron injection layer 115 in the first embodiment can be used in the same way. Among them, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferable because they have good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. Organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen, and mPPhen2P are preferable, and organic compounds having a phenanthroline dimer structure such as mPPhen2P are more preferable because they have excellent stability. In addition, it is preferable to use an organic compound having an electron transporting property and a high HOMO level, such as 2mPCCzPDBq or DACT-II, since this makes it possible to obtain a light-emitting device with a low driving voltage.

[0247] The electron transport layer preferably contains an organic compound having an acid dissociation constant pKa of less than 4 and having electron transport properties.

[0248] The electron transport layer 114 may have a laminated structure. When the electron transport layer 114 has a laminated structure, a layer in contact with the light-emitting layer 113 may function as a hole-blocking layer. When the electron transport layer in contact with the light-emitting layer is made to function as a hole-blocking layer, it is preferable to use a material whose HOMO level is 0.5 eV or more lower than the HOMO level of the material contained in the light-emitting layer.

[0249] The electron injection layer 115 is formed between the electron transport layer 114 and the second electrode 102. The configuration of the electron injection layer 115 has been described in detail in the first embodiment, and therefore will not be described repeatedly.

[0250] The second electrode 102 is an electrode including a cathode. The second electrode 102 may have a laminated structure, in which case a layer in contact with the EL layer 103 functions as the cathode. As a material for forming the cathode, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such a cathode material include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys (MgAg, AlLi) and compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), etc.) containing these, rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these, etc. However, by providing the electron injection layer 115 or a thin film of the above-mentioned material with a small work function 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 can be used as the cathode regardless of the magnitude of the work function.

[0251] In addition, when the second electrode 102 is formed from a material that is transparent to visible light, a light-emitting device can be formed that emits light from the second electrode 102 side, and when the first electrode 101 is formed from a material that is transparent to visible light, a light-emitting device can be formed that emits light from the first electrode 101 side.

[0252] These conductive materials can be formed into a film by a dry method such as a vacuum deposition method or a sputtering method, an inkjet method, a spin coating method, etc. Also, they may be formed by a wet method using a sol-gel method, or may be formed by a wet method using a paste of a metal material.

[0253] In the case of a top-emission type light-emitting device, the light extraction efficiency can be improved by forming a capping layer by evaporating an organic compound on the second electrode. The capping layer may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, the light extraction efficiency can be further improved by using organic compounds with different refractive indices.

[0254] In addition, various methods, whether dry or wet, can be used to form the EL layer 103. For example, a vacuum deposition method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method, or a spin coating method may be used.

[0255] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0256] Next, an embodiment of a light-emitting device having a configuration in which a plurality of light-emitting units are stacked (also called a stacked device or a tandem device) will be described with reference to FIG. 1(B). This light-emitting device has a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has a configuration almost similar to that of the EL layer 103 shown in FIG. 1(A). In other words, it can be said that the light-emitting device shown in FIG. 1(B) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) is a light-emitting device having one light-emitting unit.

[0257] 1(B), a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between a first electrode 501 and a second electrode 502, and an intermediate layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The first electrode 501 and the second electrode 502 correspond to the first electrode 101 and the second electrode 102 in FIG. 1(A), respectively, and the same as those described in the description of FIG. 1(A) can be applied to them. In addition, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures.

[0258] The intermediate layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied between the first electrode 501 and the second electrode 502. That is, in the case of FIG. 1(B), when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, the intermediate layer 513 only needs to inject electrons into the first light-emitting unit 511 and inject holes into the second light-emitting unit 512.

[0259] The intermediate layer 513 includes a charge generation layer. The charge generation layer includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material listed above as a material that can form the hole injection layer 111. The P-type layer 117 may be formed by laminating a film containing an acceptor material and a film containing a hole transport material, both of which are materials that form the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the cathode, and the light-emitting device operates.

[0260] In addition, it is preferable that the intermediate layer 513 includes, in addition to the P-type layer 117, one or both of an electron relay layer 118 and an N-type layer 119.

[0261] The electron relay layer 118 contains at least a substance having an electron transporting property, and has a function of preventing an interaction between the N-type layer 119 and the P-type layer 117 and smoothly transferring electrons. The LUMO level of the substance having an electron transporting property contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor substance in the P-type layer 117 and the LUMO level of the substance contained in the layer in contact with the intermediate layer 513 in the electron transport layer 114. The specific energy level of the LUMO level of the substance having an electron transporting property used in the electron relay layer 118 is -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. Note that the substance having an electron transporting property used in the electron relay layer 118 is preferably a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0262] The N-type layer 119 can be made of a material with high electron injection properties, such as an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)).

[0263] In addition, when the N-type layer 119 is formed containing a substance having an electron transporting property and a donor substance, as the donor substance, an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (an alkali metal compound (including an oxide such as lithium oxide, a halide, or a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, or a carbonate), or a rare earth metal compound (including an oxide, a halide, or a carbonate)), or an organic compound such as tetrathianaphthacene (abbreviation: TTN), nickelocene, or decamethylnickelocene can be used. Note that as the substance having an electron transporting property, a material similar to the material constituting the electron transporting layer 114 described above can be used.

[0264] Alternatively, instead of the N-type layer 119, a layer containing an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group, which have been described as being used for the electron injection layer in the first embodiment, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring may be formed at the same position as the N-type layer 119. Even in the case of this configuration, a tandem light-emitting device having good characteristics can be fabricated.

[0265] When the anode side surface of the light-emitting unit is in contact with the intermediate layer 513, the charge generation layer of the intermediate layer 513 can also function as the hole injection layer of the light-emitting unit, so the light-emitting unit does not need to be provided with a hole injection layer. When the cathode side surface of the light-emitting unit is in contact with the intermediate layer 513, the intermediate layer 513 can also function as the electron injection layer of the light-emitting unit, so the light-emitting unit does not need to be provided with an electron injection layer.

[0266] 1B, a light-emitting device having two light-emitting units has been described, but the present invention can be applied to a light-emitting device having three or more light-emitting units stacked in the same manner. By disposing a plurality of light-emitting units between a pair of electrodes and separating them with an intermediate layer 513 as in the light-emitting device according to this embodiment, it is possible to realize an element that can emit light with high luminance while keeping the current density low and has a long life. In addition, it is possible to realize a light-emitting device that can be driven at a low voltage and consumes low power.

[0267] In addition, by making the emission colors of the respective light-emitting units different, it is possible to obtain light emission of a desired color from the light-emitting device as a whole. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green emission colors from the first light-emitting unit and blue emission color from the second light-emitting unit.

[0268] Each layer and electrode, such as the EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the intermediate layer 513, can be formed by using, for example, a deposition method (including a vacuum deposition method), a droplet discharge method (also called an ink-jet method), a coating method, a gravure printing method, etc. They may also include a low molecular weight material, a medium molecular weight material (including an oligomer and a dendrimer), or a polymer material.

[0269] FIG. 2A illustrates two adjacent light-emitting devices (light-emitting device 130a and light-emitting device 130b) included in a display device of one embodiment of the present invention.

[0270] The light-emitting device 130a has an EL layer 103a between a first electrode 101a on an insulating layer 175 and an opposing second electrode 102. The EL layer 103a has a configuration including a hole injection layer 111a, a hole transport layer 112a, a light-emitting layer 113a, an electron transport layer 114a, and an electron injection layer 115a, but may have a different laminate structure.

[0271] The light-emitting device 130b has an EL layer 103b between a first electrode 101b on an insulating layer 175 and an opposing second electrode 102. The EL layer 103b has a configuration including a hole injection layer 111b, a hole transport layer 112b, a light-emitting layer 113b, an electron transport layer 114b, and an electron injection layer 115b, but may have a different laminate structure.

[0272] The configurations of the electron transport layer 114a and the electron injection layer 115a in the light-emitting device 130a, and the configurations of the electron transport layer 114b and the electron injection layer 115b in the light-emitting device 130b are preferably as described in the first embodiment.

[0273] Note that the second electrode 102 is preferably a continuous layer shared by the light-emitting device 130a and the light-emitting device 130b. The EL layer 103a and the EL layer 103b are independent from each other because they are processed by photolithography after the electron-injection layer 115a and the electron-injection layer 115b are formed, respectively. A light-emitting device having good characteristics can be obtained even if the light-emitting device according to one embodiment of the present invention is processed by photolithography after the electron-injection layer 115a and the electron-injection layer 115b are formed, respectively. Note that the electron-injection layer 115a and the electron-injection layer 115b may be a continuous layer shared by the light-emitting device 130a and the light-emitting device 130b as shown in FIG. 22(A).

[0274] The edge (outline) of the EL layer 103a is processed by photolithography, so that it is roughly aligned vertically to the substrate. The edge (outline) of the EL layer 103b is processed by photolithography, so that it is roughly aligned vertically to the substrate.

[0275] In addition, since the EL layer 103a and the EL layer 103b are processed by photolithography, a gap d exists between the EL layer 103a and the EL layer 103b. In addition, since the EL layer is processed by photolithography, the distance between the first electrode 101a and the first electrode 101b can be made smaller than that in the case of performing mask deposition, and can be set to 0.5 μm or more and 5 μm or less.

[0276] FIG. 2B shows a diagram of two adjacent tandem light-emitting devices (light-emitting device 130c, light-emitting device 130d) fabricated by photolithography.

[0277] The light-emitting device 130c has an EL layer 103c between the first electrode 101c and the second electrode 102 on the insulating layer 175. The EL layer 103c has a configuration in which a first light-emitting unit 501c and a second light-emitting unit 502c are laminated with an intermediate layer 116c sandwiched therebetween. Although an example in which two light-emitting units are laminated is shown in FIG. 2, a configuration in which three or more light-emitting units are laminated may also be used. The first light-emitting unit 501c has a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 116c has a P-type layer 117c, an electron relay layer 118c, and an N-type layer 119c. The electron relay layer 118c may or may not be present. The second light-emitting unit 502c includes a second hole-transporting layer 112c_2, a second light-emitting layer 113c_2, a second electron-transporting layer 114c_2, and an electron-injecting layer 115c.

[0278] The light-emitting device 130d has an EL layer 103d between the first electrode 101d and the second electrode 102 on the insulating layer 175. The EL layer 103d has a configuration in which a first light-emitting unit 501d and a second light-emitting unit 502d are laminated with an intermediate layer 116d sandwiched therebetween. Although an example in which two light-emitting units are laminated is shown in FIG. 2, a configuration in which three or more light-emitting units are laminated may also be used. The first light-emitting unit 501d has a hole injection layer 111d, a first hole transport layer 112d_1, a first light-emitting layer 113d_1, and a first electron transport layer 114d_1. The intermediate layer 116d has a P-type layer 117d, an electron relay layer 118d, and an N-type layer 119d. The electron relay layer 118d may or may not be present. The second light-emitting unit 502d includes a second hole-transporting layer 112d_2, a second light-emitting layer 113d_2, a second electron-transporting layer 114d_2, and an electron-injecting layer 115d.

[0279] In the light-emitting devices 130c and 130d, the electron-injection layers 115c and 115d preferably have the same configuration as described in the first embodiment.

[0280] Note that the second electrode 102 is preferably a continuous layer shared by the light-emitting device 130c and the light-emitting device 130d. The EL layer 103c and the EL layer 103d are independent from each other because they are processed by photolithography after the electron injection layer 115c and the electron injection layer 115d are formed, respectively. A light-emitting device having good characteristics can be obtained even if the light-emitting device according to one embodiment of the present invention is processed by photolithography after the electron injection layer 115c and the electron injection layer 115d are formed, respectively. Note that the electron injection layer 115c and the electron injection layer 115d may be a continuous layer shared by the light-emitting device 130c and the light-emitting device 130d, as shown in FIG. 22(B).

[0281] The edge (outline) of the EL layer 103c is processed by photolithography so that it is roughly aligned vertically to the substrate, and the edge (outline) of the EL layer 103d is processed by photolithography so that it is roughly aligned vertically to the substrate.

[0282] In addition, since the EL layer 103c and the EL layer 103d are processed by photolithography, a gap d exists between the EL layer 103c and the EL layer 103d. In addition, since the EL layer is processed by photolithography, the distance between the first electrode 101c and the first electrode 101d can be made smaller than that when performing mask deposition, and can be set to 0.5 μm or more and 5 μm or less.

[0283] In the light-emitting device of one embodiment of the present invention, the EL layer is processed by photolithography, so that the light-emitting device can be processed with sufficient accuracy to manufacture a high-definition display device. In addition, the photolithography process can be performed on the electron injection layer far from the light-emitting layer without contamination by alkali metal, so that the light-emitting device can have good characteristics. As described above, the light-emitting device of one embodiment of the present invention having such a structure can realize a high-definition display device and can have good characteristics.

[0284] In the light-emitting device according to one embodiment of the present invention, the EL layer in the light-emitting device is processed at one time by photolithography, so that the contours of all layers included in the EL layer are approximately the same. In this specification, approximately the same means that the deviation between the contour A of layer A and the contour B of layer B included in the EL layer is within 5% of the width of the EL layer on a line perpendicular to the contours of the compared portions. In addition, when the end face of the EL layer has a tapered shape, continuous changes in the contour are allowed.

[0285] The structure of this embodiment mode can be used in appropriate combination with other structures.

[0286] (Embodiment 3) In this embodiment, a mode in which a light-emitting device of one embodiment of the present invention is used as a display element of a display device will be described.

[0287] As shown in FIGS. 3A and 3B, a plurality of light emitting devices 130 are formed on an insulating layer 175 to constitute a display device.

[0288] The display device has a pixel portion 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 has a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0289] In this specification and the like, when describing matters common to, for example, the subpixels 110R, 110G, and 110B, they may be referred to as subpixels 110. When describing matters common to other components distinguished by alphabets, they may be described using symbols without the alphabets.

[0290] The sub-pixel 110R emits red light, the sub-pixel 110G emits green light, and the sub-pixel 110B emits blue light. This allows a full-color image to be displayed in the pixel section 177. In the present embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are described as an example, but combinations of sub-pixels of other colors may be used. The number of sub-pixels is not limited to three, and may be four or more. Examples of the four sub-pixels include sub-pixels of four colors, R, G, B, and white (W), sub-pixels of four colors, R, G, B, and yellow (Y), and sub-pixels of R, G, B, and infrared (IR).

[0291] 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.

[0292] 3A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction. Note that subpixels of different colors may be arranged side by side in the Y direction, and subpixels of the same color may be arranged side by side in the X direction.

[0293] A connection section 140 is provided outside the pixel section 177, and a region 141 may be provided. The region 141 is provided between the pixel section 177 and the connection section 140. The EL layer 103 is provided in the region 141. Also, the connection section 140 is provided with a conductive layer 151C.

[0294] 3A shows an example in which the region 141 and the connection portion 140 are located on the right side of the pixel portion 177, but the positions of the region 141 and the connection portion 140 are not particularly limited. The region 141 and the connection portion 140 may be singular or plural.

[0295] Fig. 3(B) is an example of a cross-sectional view between dashed line A1-A2 in Fig. 3(A). As shown in Fig. 3(B), the display device has an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). An opening reaching the conductive layer 172 is provided in the insulating layer 175, the insulating layer 174, and the insulating layer 173, and a plug 176 is provided to fill the opening.

[0296] In the pixel section 177, the light emitting device 130 is provided on the insulating layer 175 and the plug 176. A protective layer 131 is provided so as to cover the light emitting device 130. The substrate 120 is bonded onto the protective layer 131 by a resin layer 122. In addition, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are preferably provided between adjacent light emitting devices 130.

[0297] 3B shows multiple cross sections of the inorganic insulating layer 125 and the insulating layer 127, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are connected to one another when the display device is viewed from above. In other words, it is preferable that the insulating layer 127 is an insulating layer having an opening over the first electrode.

[0298] In FIG. 3B, the light emitting device 130 includes a light emitting device 130R, a light emitting device 130G, and a light emitting device 130B. The light emitting device 130R, the light emitting device 130G, and the light emitting device 130B emit light of different colors. For example, the light emitting device 130R can emit red light, the light emitting device 130G can emit green light, and the light emitting device 130B can emit blue light. The light emitting device 130R, the light emitting device 130G, or the light emitting device 130B may emit other visible light or infrared light.

[0299] The display device of one embodiment of the present invention can be, for example, a top emission type that emits light in a direction opposite to a substrate on which a light-emitting device is formed. Note that the display device of one embodiment of the present invention may be a bottom emission type.

[0300] The light-emitting device 130R has the configuration as shown in the first and second embodiments. It has a first electrode 101R (pixel electrode) consisting of a conductive layer 151R and a conductive layer 152R, an EL layer 103R on the first electrode 101R, and a second electrode 102 (common electrode) on the EL layer 103R. The electron injection layer, which is the layer on the outermost surface of the EL layer 103R, has the configuration as described in the first embodiment. With this configuration, damage to the light-emitting layer or active layer in the photolithography process can be suppressed, and good film quality and electrical characteristics can be expected. In addition, since the electron transport layer is a mixed layer of an organic compound having electron transport properties and an organic compound having hole transport properties, it is possible to provide a display device in which an increase in driving voltage is suppressed.

[0301] The light-emitting device 130G has the configuration as shown in the first and second embodiments. It has a first electrode 101G (pixel electrode) consisting of a conductive layer 151G and a conductive layer 152G, an EL layer 103G on the first electrode 101G, and a second electrode 102 (common electrode) on the EL layer 103G. The electron injection layer, which is the outermost layer of the EL layer 103G, has the configuration as described in the first embodiment. With such a configuration, damage to the light-emitting layer or the active layer in the photolithography process can be suppressed, and good film quality and electrical characteristics can be expected. In addition, since the electron transport layer is a mixed layer of an organic compound having an electron transport property and an organic compound having a hole transport property, it is possible to provide a display device in which an increase in driving voltage is suppressed.

[0302] The light-emitting device 130B has the configuration as shown in the first and second embodiments. It has a first electrode 101B (pixel electrode) consisting of a conductive layer 151B and a conductive layer 152B, an EL layer 103B on the first electrode 101B, and a second electrode 102 (common electrode) on the EL layer 103B. The electron injection layer, which is the outermost layer of the EL layer 103B, has the configuration as described in the first embodiment. With such a configuration, damage to the light-emitting layer or the active layer in the photolithography process can be suppressed, and good film quality and electrical characteristics can be expected. In addition, since the electron transport layer is a mixed layer of an organic compound having an electron transport property and an organic compound having a hole transport property, it is possible to provide a display device in which an increase in driving voltage is suppressed.

[0303] One of a pixel electrode (first electrode) and a common electrode (second electrode) of a light-emitting device functions as an anode, and the other functions as a cathode. In this embodiment, unless otherwise specified, the pixel electrode functions as an anode, and the common electrode functions as a cathode.

[0304] The EL layer 103R, the EL layer 103G, and the EL layer 103B are independent in an island shape for each light-emitting device or for each light-emitting color. It is preferable that the EL layer 103R, the EL layer 103G, and the EL layer 103B do not overlap each other. By providing the EL layer 103 in an island shape for each light-emitting device 130, it is possible to suppress leakage current between adjacent light-emitting devices 130 even in a high-definition display device. This makes it possible to prevent crosstalk and realize a display device with extremely high contrast. In particular, it is possible to realize a display device with high current efficiency at low luminance.

[0305] The island-shaped EL layer 103 is formed by depositing an EL film and processing the EL film by using a photolithography method.

[0306] The EL layer 103 is preferably provided so as to cover the upper surface and side surfaces of the first electrode 101 (pixel electrode) of the light-emitting device 130. This makes it easier to increase the aperture ratio of the display device compared to a configuration in which the end of the EL layer 103 is located inside the end of the pixel electrode. In addition, by covering the side surfaces of the pixel electrode of the light-emitting device 130 with the EL layer 103, contact between the pixel electrode and the second electrode 102 can be prevented, and therefore short-circuiting of the light-emitting device 130 can be prevented.

[0307] In the display device of one embodiment of the present invention, the first electrode 101 (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in the example shown in FIG. 3B, the first electrode 101 of the light-emitting device 130 has a stacked structure of a conductive layer 151 provided on the insulating layer 171 side and a conductive layer 152 provided on the EL layer side.

[0308] 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), neodymium (Nd), and alloys containing appropriate combinations of these metals can also be used.

[0309] The conductive layer 152 can be made of an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon. For example, it is preferable to use a conductive oxide 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. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, and therefore can be suitably used for the conductive layer 152.

[0310] The conductive layer 151 may have a stacked structure of multiple layers having different materials, and the conductive layer 152 may have a stacked structure of multiple layers having different materials. In this case, the conductive layer 151 may have a layer using a material that can be used for the conductive layer 152, such as a conductive oxide, or the conductive layer 152 may have a layer using a material that can be used for the conductive layer 151, such as a metal material. For example, when the conductive layer 151 has a stacked structure of two or more layers, a layer in contact with the conductive layer 152 can be a layer using a material that can be used for the conductive layer 152.

[0311] 3B, the end of the conductive layer 151 has a tapered shape. Specifically, the end of the conductive layer 151 preferably has a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surface of the conductive layer 151 also has a tapered shape. By making the side surface of the conductive layer 152 tapered, the coverage of the EL layer 103 provided along the side surface of the conductive layer 152 can be improved.

[0312] The ends of the conductive layers 151 and 152 may not have a tapered shape, that is, may be approximately vertical. The ends of the EL layer 103 are preferably located inside the first electrode 101. In this case, a leakage current through the EL layer 103 can be reduced, and a display device with low driving voltage and excellent display performance can be obtained.

[0313] In the display device of one embodiment of the present invention, the light-emitting device 130 has the structure described in Embodiments 1 and 2; therefore, the light-emitting device can have high reliability.

[0314] Next, an example of a method for manufacturing a display device having the structure shown in FIG. 3A will be described with reference to FIGS.

[0315] [Example of manufacturing method] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum deposition method, a pulsed laser deposition (PLD) method, an atomic layer deposition (ALD) method, or the like.

[0316] Furthermore, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by wet film formation methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0317] Furthermore, when processing the thin films that constitute the display device, they can be processed using, for example, a photolithography method.

[0318] In the photolithography method, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. may also be used. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays may also be used as the light used for exposure. An electron beam may also be used instead of the light used for exposure.

[0319] The thin film can be etched by dry etching, wet etching, sandblasting, or the like.

[0320] 4(A), an insulating layer 171 is formed on a substrate (not shown). Then, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 so as to cover the conductive layer 172 and the conductive layer 179. Then, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0321] The substrate may be a substrate having at least a heat resistance sufficient to withstand a subsequent heat treatment, such as a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, a single crystal semiconductor substrate made of silicon, silicon carbide, or the like, a polycrystalline semiconductor substrate, a compound semiconductor substrate made of silicon germanium, or the like, or an SOI substrate.

[0322] 4A, an opening reaching the conductive layer 172 is formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Then, a plug 176 is formed to fill the opening.

[0323] 4A, a conductive film 151f which will later become the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, and the conductive layer 151C, and 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 are formed on the plug 176 and the insulating layer 175. For example, a metal material can be used as the conductive film 151f. For example, an oxide containing one or more elements selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used as the conductive film 152f.

[0324] 4A, a resist mask 191 is formed over the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist) and then performing exposure and development.

[0325] 4B, for example, the conductive film 151f and the conductive film 152f are removed from the region not overlapping with the resist mask 191. As a result, the conductive layer 151 and the conductive layer 152 are formed.

[0326] 4(C), the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, for example.

[0327] Next, as shown in FIG. 4(D), insulating film 156f, which will later become insulating layer 156R, insulating layer 156G, insulating layer 156B, and insulating layer 156C, is formed on conductive layer 152R, conductive layer 152G, conductive layer 152B, conductive layer 152C, and insulating layer 175.

[0328] The insulating film 156f can be an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film, for example, a silicon oxynitride film.

[0329] Subsequently, as shown in FIG. 4(E), the insulating film 156f is processed to form an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C.

[0330] 5(A), the organic compound film 103Rf is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the insulating layer 175. Note that, as shown in FIG. 5(A), the organic compound film 103Rf is not formed on the conductive layer 152C.

[0331] Subsequently, as shown in FIG. 5(A), a sacrificial film 158Rf and a mask film 159Rf are formed.

[0332] By providing the sacrificial film 158Rf 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.

[0333] The sacrificial film 158Rf is made of a film having high resistance to the processing conditions of the organic compound film 103Rf, specifically, a film having a high etching selectivity with respect to the organic compound film 103Rf. The mask film 159Rf is made of a film having a high etching selectivity with respect to the sacrificial film 158Rf.

[0334] The sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat-resistant temperature of the organic compound film 103Rf. The substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf is typically 100° C. or higher and 200° C. or lower, preferably 100° C. or higher and 150° C. or lower, and more preferably 100° C. or higher and 120° C. or lower.

[0335] The sacrificial film 158Rf and the mask film 159Rf are preferably made of a film that can be removed by wet etching or dry etching.

[0336] In addition, the sacrificial film 158Rf formed on and in contact with the organic compound film 103Rf is preferably formed using a formation method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, the ALD method or the vacuum deposition method is more preferable than the sputtering method.

[0337] The sacrificial film 158Rf and the mask film 159Rf may each be made of 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, for example.

[0338] The sacrificial film 158Rf and the mask film 159Rf may be made of, for example, 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 material containing the metal material. In particular, it is preferable to use a low melting point material such as aluminum or silver. It is preferable to use a metal material capable of blocking ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf, since it is possible to suppress irradiation of ultraviolet rays during pattern exposure to the organic compound film 103Rf, and thus to suppress deterioration of the organic compound film 103Rf.

[0339] Furthermore, for 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), and indium tin oxide containing silicon can be used.

[0340] In addition, in the above metal oxide, an element M (M is one or more elements selected from 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.

[0341] For the sacrificial film 158Rf and the mask film 159Rf, it is preferable to use a semiconductor material such as silicon or germanium because it has a high affinity with the semiconductor manufacturing process, or a compound containing the above semiconductor material may be used.

[0342] Moreover, various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, an oxide insulating film is preferable because it has higher adhesion to the organic compound film 103Rf than a nitride insulating film.

[0343] 5(A), a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and then performing exposure and development.

[0344] The resist mask 190R is provided in a position overlapping with the conductive layer 152R. The resist mask 190R is preferably provided also in a position overlapping with the conductive layer 152C, which can prevent the conductive layer 152C from being damaged during the manufacturing process of the display device.

[0345] 5(B), a resist mask 190R is used to remove a portion of the mask film 159Rf to form a mask layer 159R. The mask layer 159R remains on the conductive layer 152R and the conductive layer 152C. The resist mask 190R is then removed. The mask layer 159R is used as a mask (also called a hard mask) to remove a portion of the sacrificial film 158Rf to form a sacrificial layer 158R.

[0346] 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, it is preferable to use an acid aqueous solution such as a developing solution, an alkaline aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, a chemical solution using dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture of these.

[0347] Furthermore, when dry etching is used in processing the sacrificial film 158Rf, deterioration of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0348] The resist mask 190R can be removed in the same manner as the resist mask 191.

[0349] 5(B), the organic compound film 103Rf is processed to form the EL layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove a part of the organic compound film 103Rf to form the EL layer 103R.

[0350] 5B, a laminated structure of the EL layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. Also, the conductive layers 152G and 152B are exposed.

[0351] The organic compound film 103Rf is preferably processed by anisotropic etching, particularly anisotropic dry etching, or wet etching may be used.

[0352] When dry etching is used, deterioration of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0353] Moreover, a gas containing oxygen may be used as the etching gas. When the etching gas contains oxygen, the etching speed can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching speed. This makes it possible to suppress damage to the organic compound film 103Rf. Furthermore, problems such as adhesion of reaction products generated during etching can be suppressed.

[0354] When using a dry etching method, it is preferable to use a gas containing one or more of H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or a group 18 element such as He or Ar as an etching gas. Alternatively, it is preferable to use a gas containing one or more of these elements and oxygen as an etching gas. Alternatively, oxygen gas may be used as an etching gas.

[0355] Next, as shown in FIG. 6(A), an organic compound film 103Gf that will later become the EL layer 103G is formed.

[0356] The organic compound film 103Gf can be formed by the same method as that used for forming the organic compound film 103Rf, and can have the same configuration as the organic compound film 103Rf.

[0357] 6A, a sacrificial film 158Gf and a mask film 159Gf are formed in this order. Then, a resist mask 190G is formed. The material and the forming method of the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The material and the forming method of the resist mask 190G are the same as those applicable to the resist mask 190R.

[0358] The resist mask 190G is provided in a position overlapping with the conductive layer 152G.

[0359] 6(B), a resist mask 190G is used to remove a portion of the mask film 159Gf to form a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. The resist mask 190G is then removed. The mask layer 159G is then used as a mask to remove a portion of the sacrificial film 158Gf to form a sacrificial layer 158G. The organic compound film 103Gf is then processed to form an EL layer 103G.

[0360] Subsequently, as shown in FIG. 6(C), an organic compound film 103Bf is formed.

[0361] The organic compound film 103Bf can be formed by the same method as that used for forming the organic compound film 103Rf, and can have the same structure as the organic compound film 103Rf.

[0362] 6(C), a sacrificial film 158Bf and a mask film 159Bf are formed in this order. Then, a resist mask 190B is formed. The material and the forming method of the sacrificial film 158Bf and the mask film 159Bf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The material and the forming method of the resist mask 190B are the same as those applicable to the resist mask 190R.

[0363] The resist mask 190B is provided in a position overlapping with the conductive layer 152B.

[0364] 6(D), a resist mask 190B is used to remove a portion of the mask film 159Bf to form a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. The resist mask 190B is then removed. The mask layer 159B is then used as a mask to remove a portion of the sacrificial film 158Bf to form a sacrificial layer 158B. The organic compound film 103Bf is then processed to form the EL layer 103B. For example, the mask layer 159B and the sacrificial layer 158B are used as hard masks to remove a portion of the organic compound film 103Bf to form the EL layer 103B.

[0365] 6D, a laminated structure of the EL layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. Also, the mask layers 159R and 159G are exposed.

[0366] It is preferable that the side surfaces of the EL layer 103R, the EL layer 103G, and the EL layer 103B are perpendicular or approximately perpendicular to the surface on which they are formed. For example, it is preferable that the angle between the surface on which they are formed and these side surfaces is 60 degrees or more and 90 degrees or less.

[0367] As described above, the distance between two adjacent ones of the EL layer 103R, the EL layer 103G, and the EL layer 103B formed by the photolithography method can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, the distance can be defined, for example, as the distance between two adjacent opposing ends of the EL layer 103R, the EL layer 103G, and the EL layer 103B. In this way, by narrowing the distance between the island-like EL layers, a display device having high definition and a large aperture ratio can be provided. In addition, the distance between the first electrodes between adjacent light-emitting devices can also be narrowed, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. Note that the distance between the first electrodes between adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0368] Subsequently, as shown in FIG. 7(A), it is preferable to remove the mask layers 159R, 159G, and 159B.

[0369] The mask layer can be removed by the same method as the mask film processing method. In particular, by using a wet etching method, damage to the EL layer 103 during removal of the mask layer can be reduced compared to the case of using a dry etching method.

[0370] The mask layer may also be removed by dissolving it in a polar solvent such as water or alcohol, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0371] After removing the mask layer, a drying treatment may be performed to remove water adsorbed on the surface. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., and more preferably 70° C. to 120° C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0372] Subsequently, as shown in FIG. 7(B), an inorganic insulating film 125f is formed.

[0373] Subsequently, as shown in FIG. 7(C), an insulating film 127f, which will later become the insulating layer 127, is formed on the inorganic insulating film 125f.

[0374] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or more, 80°C or more, 100°C or more, or 120°C or more, and 200°C or less, 180°C or less, 160°C or less, 150°C or less, or 140°C or less.

[0375] As the inorganic insulating film 125f, it is preferable to form an insulating film having a thickness of 3 nm or more, 5 nm or more, or 10 nm or more and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above substrate temperature range.

[0376] The inorganic insulating film 125f is preferably formed by, for example, the ALD method. By using the ALD method, damage during film formation can be reduced, and a film with high coverage can be formed, which is preferable. As the inorganic insulating film 125f, for example, an aluminum oxide film is preferably formed by the ALD method.

[0377] The insulating film 127f is preferably formed by using the above-mentioned wet film formation method. The insulating film 127f is preferably formed by using a photosensitive material, for example, by spin coating, and more specifically, is preferably formed by using a photosensitive resin composition containing an acrylic resin.

[0378] Subsequently, exposure is performed to expose a part of the insulating film 127f to visible light or ultraviolet light. The insulating layer 127 is formed in a region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C.

[0379] 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 as to have a portion overlapping with the upper surface of the conductive layer 151.

[0380] The light used for exposure preferably contains i-line (wavelength 365 nm), and may contain at least one of g-line (wavelength 436 nm) and h-line (wavelength 405 nm).

[0381] Subsequently, as shown in FIG. 8(A), development is performed to remove the exposed area of ​​the insulating film 127f, thereby forming an insulating layer 127a.

[0382] 8(B), an etching process is performed using the insulating layer 127a as a mask to remove a part of the inorganic insulating film 125f and to thin the thickness of the sacrificial layers 158R, 158G, and 158B. As a result, the inorganic insulating layer 125 is formed under the insulating layer 127a. In addition, the surfaces of the thin parts of the sacrificial layers 158R, 158G, and 158B are exposed. In the following, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0383] The first etching process can be performed by dry etching or wet etching. Note that, when the inorganic insulating film 125f is formed using the same material as the sacrificial layers 158R, 158G, and 158B, the first etching process can be performed at once, which is preferable.

[0384] When dry etching is performed, it is preferable to use a chlorine-based gas. As the chlorine-based gas, Cl2, BCl3, SiCl4, CCl4, etc. can be used alone or in a mixture of two or more gases. In addition, oxygen gas, hydrogen gas, helium gas, argon gas, etc. can be appropriately added alone or in a mixture of two or more gases to the chlorine-based gas. By using dry etching, the thin film regions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can be formed with good in-plane uniformity.

[0385] As the dry etching apparatus, a dry etching apparatus having a high density plasma source can be used. As the dry etching apparatus having a high density plasma source, for example, an inductively coupled plasma (ICP) etching apparatus can be used. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes can be used.

[0386] In addition, it is preferable to perform the first etching process by wet etching. By using the wet etching method, damage to the EL layer 103R, the EL layer 103G, and the EL layer 103B can be reduced compared to the case of using the dry etching method. For example, the wet etching can be performed using an alkaline solution. For example, a TMAH aqueous solution, which is an alkaline solution, can be used for wet etching of an aluminum oxide film. Also, an acid solution containing fluoride can be used. In this case, the wet etching can be performed by the paddle method. Note that, when the inorganic insulating film 125f is formed using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the above-mentioned etching process can be performed at once, which is preferable.

[0387] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the etching process is stopped when the film thickness becomes thin. In this way, by leaving the corresponding sacrificial layers 158R, 158G, and 158B on the EL layers 103R, 103G, and 103B, it is possible to prevent the EL layers 103R, 103G, and 103B from being damaged in the subsequent process.

[0388] Next, the entire substrate is exposed to light, and it is preferable to irradiate the insulating layer 127a with visible light or ultraviolet light. The energy density of the exposure is 0 mJ / cm 2 Larger, 800mJ / cm2 It is preferable to set the concentration to 0 mJ / cm or less. 2 Larger than 500mJ / cm 2 It is more preferable to set the following. By performing such exposure after development, the transparency of the insulating layer 127a can be improved in some cases. In addition, the substrate temperature required for a heat treatment for transforming the insulating layer 127a into a tapered shape in a later step can be reduced in some cases.

[0389] Here, the presence of a barrier insulating layer against oxygen (e.g., an aluminum oxide film or the like) as the sacrificial layers 158R, 158G, and 158B can reduce the diffusion of oxygen into the EL layers 103R, 103G, and 103B.

[0390] Next, a heat treatment (also referred to as post-baking) is performed. By performing the heat treatment, the insulating layer 127a can be transformed into an insulating layer 127 having tapered sides (FIG. 8C). The heat treatment is performed at a temperature lower than the heat resistance temperature of the EL layer. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., more preferably 70° C. to 130° C. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. The heating atmosphere may be an atmospheric pressure atmosphere or a reduced pressure atmosphere. This can improve the adhesion between the insulating layer 127 and the inorganic insulating layer 125 and also improve the corrosion resistance of the insulating layer 127.

[0391] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the sacrificial layers 158R, 158G, and 158B are left in a state where their thicknesses are reduced, thereby preventing the EL layers 103R, 103G, and 103B from being damaged and deteriorated in the heat treatment, thereby improving the reliability of the light-emitting device.

[0392] 9(A), an etching process is performed using the insulating layer 127 as a mask to remove parts of the sacrificial layers 158R, 158G, and 158B. As a result, openings are formed in the sacrificial layers 158R, 158G, and 158B, respectively, and the upper surfaces of the EL layers 103R, 103G, 103B, and the conductive layer 152C are exposed. Note that, hereinafter, this etching process may be referred to as a second etching process.

[0393] An end portion of the inorganic insulating layer 125 is covered with an insulating layer 127. Also, Fig. 9(A) shows an example in which a part of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered with the insulating layer 127, and the tapered portion formed by the second etching process is exposed.

[0394] The second etching process is performed by wet etching. By using the wet etching method, damage to the EL layer 103R, the EL layer 103G, and the EL layer 103B can be reduced compared to the case of using the dry etching method. The wet etching can be performed using, for example, an alkaline solution or an acidic solution. It is preferable to use an aqueous solution so that the EL layer 103 does not dissolve.

[0395] 9(B), a common electrode 155 is formed on the EL layer 103R, the EL layer 103G, the EL layer 103B, the conductive layer 152C, and the insulating layer 127. The common electrode 155 can be formed by a method such as a sputtering method or a vacuum deposition method.

[0396] 9C, the protective layer 131 is formed on the common electrode 155. The protective layer 131 can be formed by a method such as a vacuum deposition method, a sputtering method, a CVD method, or an ALD method.

[0397] Then, the substrate 120 is attached over the protective layer 131 using the resin layer 122, so that a display device can be manufactured. As described above, in a manufacturing method of a display device according to one embodiment of the present invention, the insulating layer 156 is provided so as to have a region overlapping with a side surface of the conductive layer 151, and the conductive layer 152 is formed so as to cover the conductive layer 151 and the insulating layer 156. This can increase the yield of the display device and suppress the occurrence of defects.

[0398] As described above, in the manufacturing method of the display device according to one embodiment of the present invention, the island-shaped EL layer 103R, the island-shaped EL layer 103G, and the island-shaped EL layer 103B are formed by forming a film on one surface and then processing it, instead of using a fine metal mask, so that the island-shaped layers can be formed with a uniform thickness. As a result, a high-definition display device or a display device with a high aperture ratio can be realized. Even if the definition or aperture ratio is high and the distance between the subpixels is extremely short, the EL layer 103R, the EL layer 103G, and the EL layer 103B can be prevented from contacting each other in adjacent subpixels. Therefore, leakage current can be prevented from occurring between the subpixels. As a result, crosstalk can be prevented, and a display device with extremely high contrast can be realized. Even in a display device including a tandem light-emitting device manufactured by a photolithography method, a display device with good characteristics can be provided.

[0399] (Embodiment 4) In this embodiment, a display device according to one embodiment of the present invention will be described.

[0400] The display device of the present embodiment can be a high-definition display device. Therefore, the display device of the present embodiment can be used for, for example, a display unit of a wristwatch-type or bracelet-type information terminal (wearable device), a VR device such as a head-mounted display (HMD), and a head-mounted wearable device such as a glasses-type AR device.

[0401] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0402] [Display module] 10A shows a perspective view of a display module 280. The display module 280 has a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, and may be either a display device 100B or a display device 100E, which will be described later.

[0403] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 described later can be viewed.

[0404] 10B is a perspective view showing a schematic configuration of the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are laminated on the substrate 291. A terminal portion 285 for connecting to an FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0405] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of Fig. 10(B). The various configurations described in the previous embodiment can be applied to the pixel 284a. Fig. 10(B) shows an example in which the pixel 284a has the same configuration as the pixel 178 shown in Fig. 3(A).

[0406] The pixel circuit section 283 has a plurality of pixel circuits 283a that are periodically arranged.

[0407] One pixel circuit 283a is a circuit that controls the driving of a plurality of elements included in one pixel 284a.

[0408] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0409] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. In addition, an IC may be mounted on the FPC 290.

[0410] Since the display module 280 can be configured such that one or both of the pixel circuit portion 283 and the circuit portion 282 are stacked below the pixel portion 284, the aperture ratio (effective display area ratio) of the display portion 281 can be made extremely high.

[0411] Such a display module 280 has extremely high resolution and can be suitably used in VR devices such as HMDs or glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through a lens, the display module 280 has an extremely high resolution display unit 281, so that pixels are not visible even when the display unit is enlarged with a lens, and a highly immersive display can be performed. In addition, the display module 280 is not limited to this and can be suitably used in electronic devices having a relatively small display unit.

[0412] [Display device 100A] A display device 100A shown in FIG. 11A includes a substrate 301, a light emitting device 130R, a light emitting device 130G, a light emitting device 130B, a capacitor 240, and a transistor 310.

[0413] The substrate 301 corresponds to the substrate 291 in FIGS. 10A and 10B. The transistor 310 is a transistor having a channel formation region in the substrate 301. For example, a semiconductor substrate such as a single crystal silicon substrate can be used as the substrate 301. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0414] In addition, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0415] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0416] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 located therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0417] The conductive layer 241 is provided over the insulating layer 261 and is embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0418] An insulating layer 255 is provided covering the capacitor 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0419] An insulating layer 156R is provided so as to have an area overlapping with a side surface of the conductive layer 151R, an insulating layer 156G is provided so as to have an area overlapping with a side surface of the conductive layer 151G, and an insulating layer 156B is provided so as to have an area overlapping with a side surface of the conductive layer 151B. A conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. A sacrificial layer 158R is located on the EL layer 103R, a sacrificial layer 158G is located on the EL layer 103G, and a sacrificial layer 158B is located on the EL layer 103B.

[0420] The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B are electrically connected to one of the source or the drain of the transistor 310 via an insulating layer 243, an insulating layer 255, an insulating layer 174, a plug 256 embedded in the insulating layer 175, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the plug.

[0421] Further, a protective layer 131 is provided on the light emitting devices 130R, 130G, and 130B. The substrate 120 is bonded onto the protective layer 131 by a resin layer 122. For details of the components from the light emitting devices 130 to the substrate 120, refer to the third embodiment. The substrate 120 corresponds to the substrate 292 in FIG. 10(A).

[0422] Fig. 11(B) is a modified example of the display device 100A shown in Fig. 11(A). The display device shown in Fig. 11(B) has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has an area overlapping one of the colored layer 132R, the colored layer 132G, and the colored layer 132B. In the display device shown in Fig. 11(B), the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light.

[0423] [Display device 100B] FIG. 12 shows a perspective view of the display device 100B.

[0424] The display device 100B has a configuration in which a substrate 352 and a substrate 351 are bonded together. In Fig. 12, the substrate 352 is indicated by a dashed line.

[0425] The display device 100B has a pixel unit 177, a connection unit 140, a circuit 356, wiring 355, etc. Fig. 12 shows an example in which an IC 354 and an FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Fig. 12 can also be called a display module having the display device 100B, an IC (integrated circuit), and an FPC. Here, a display device having a connector such as an FPC attached to a substrate, or a display device having an IC mounted on the substrate, is called a display module.

[0426] The connection section 140 is provided outside the pixel section 177. There may be one or more connection sections 140. The connection section 140 electrically connects the common electrode of the light emitting device and the conductive layer, and can supply a potential to the common electrode.

[0427] The circuit 356 can be, for example, a scanning line driver circuit.

[0428] The wiring 355 has a function of supplying signals and power to the pixel portion 177 and the circuit 356. The signals and power are input to the wiring 355 from the outside via the FPC 353 or from the IC 354.

[0429] 12 shows an example in which an IC 354 is provided on a substrate 351 by a chip on glass (COG) method or a chip on film (COF) method. For example, an IC having a scanning line driver circuit or a signal line driver circuit can be used as the IC 354. Note that the display device 100B and the display module may not include an IC. Also, the IC may be mounted on an FPC by a COF method, for example.

[0430] FIG. 13 shows an example of a cross section of the display device 100B, in which a portion of the region including the FPC 353, a portion of the circuit 356, a portion of the pixel portion 177, a portion of the connection portion 140, and a portion of the region including the end portion are cut away.

[0431] [Display device 100C] The display device 100C shown in FIG. 13 has, between a substrate 351 and a substrate 352, a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc.

[0432] For details of the light emitting devices 130R, 130G, and 130B, refer to the first and second embodiments.

[0433] Light-emitting device 130R has conductive layer 224R, conductive layer 151R on conductive layer 224R, and conductive layer 152R on conductive layer 151R. Light-emitting device 130G has conductive layer 224G, conductive layer 151G on conductive layer 224G, and conductive layer 152G on conductive layer 151G. Light-emitting device 130B has conductive layer 224B, conductive layer 151B on conductive layer 224B, and conductive layer 152B on conductive layer 151B.

[0434] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. An end of the conductive layer 151R is located outside an end of the conductive layer 224R. An insulating layer 156R is provided to have a region in contact with a side surface of the conductive layer 151R, and a conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R.

[0435] Conductive layer 224G, conductive layer 151G, conductive layer 152G, and insulating layer 156G in light-emitting device 130G, and conductive layer 224B, conductive layer 151B, conductive layer 152B, and insulating layer 156B in light-emitting device 130B are similar to conductive layer 224R, conductive layer 151R, conductive layer 152R, and insulating layer 156R in light-emitting device 130R, and therefore detailed description thereof will be omitted.

[0436] Recesses are formed in the conductive layers 224R, 224G, and 224B so as to cover the openings provided in the insulating layer 214. The layer 128 is embedded in the recesses.

[0437] The layer 128 has a function of planarizing the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B. The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B, which are electrically connected to the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, are provided on the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, and the layer 128. Therefore, the regions overlapping with the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B can also be used as light-emitting regions, and the aperture ratio of the pixel can be increased.

[0438] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be appropriately used for the layer 128. In particular, the layer 128 is preferably formed using an insulating material, and more preferably formed using an organic insulating material. For example, the organic insulating material that can be used for the insulating layer 127 described above can be used for the layer 128.

[0439] A protective layer 131 is provided on the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B. The protective layer 131 and the substrate 352 are bonded via an adhesive layer 142. The substrate 352 is provided with a light shielding layer 157. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light emitting device 130. In FIG. 13, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (nitrogen, argon, or the like), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light emitting device. The space may also be filled with a resin different from the adhesive layer 142 provided in a frame shape.

[0440] 13 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive layer 151C obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive layer 152C obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. Also, FIG. 13 shows an example in which an insulating layer 156C is provided so as to have an area overlapping with a side surface of the conductive layer 151C.

[0441] The display device 100B is a top emission type. Light emitted by the light emitting device is emitted to the substrate 352 side. The substrate 352 is preferably made of a material that is highly transparent to visible light. When the light emitting device emits infrared or near infrared light, it is preferably made of a material that is highly transparent to the infrared light. The pixel electrode contains a material that reflects visible light, and the counter electrode (common electrode 155) contains a material that transmits visible light.

[0442] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over a substrate 351 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistors. The insulating layer 214 is provided to cover the transistors and functions as a planarizing layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0443] Each of the insulating layers 211, 213, and 215 is preferably an inorganic insulating film.

[0444] The insulating layer 214, which functions as a planarizing layer, is preferably an organic insulating layer.

[0445] The transistor 201 and the transistor 205 each have a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a conductive layer 222a and a conductive layer 222b functioning as a source and a drain, a semiconductor layer 231, an insulating layer 213 functioning as a gate insulating layer, and a conductive layer 223 functioning as a gate.

[0446] A connection portion 204 is provided in a region of the substrate 351 where the substrate 352 does not overlap. In the connection portion 204, one of the source electrode or the drain electrode of the transistor 202 is electrically connected to the FPC 372 through the conductive layer 166 and the connection layer 242. The conductive layer 166 is an example of a laminated structure of a conductive film obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. This allows the connection portion 204 and the FPC 353 to be electrically connected through the connection layer 242.

[0447] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 facing the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, on the connection portion 140, on the circuit 356, etc. In addition, various optical members can be disposed on the outside of the substrate 352.

[0448] The materials usable for the substrate 120 can be used for the substrate 351 and the substrate 352, respectively.

[0449] The adhesive layer 142 may be made of a material that can be used for the resin layer 122 .

[0450] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0451] [Display device 100D] A display device 100D shown in FIG. 14 differs from the display device 100C shown in FIG. 13 mainly in that the display device 100D is a bottom-emission type display device.

[0452] Light emitted by the light emitting device is emitted to the side of the substrate 351. It is preferable that a material having high transparency to visible light is used for the substrate 351. On the other hand, the light transmissivity of a material used for the substrate 352 does not matter.

[0453] It is preferable to form a light-shielding layer between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205. Fig. 14 shows an example in which a light-shielding layer is provided over the substrate 351, an insulating layer 153 is provided over the light-shielding layer, and the transistors 201, 205, and the like are provided over the insulating layer 153.

[0454] Light emitting device 130R includes a conductive layer 112R, a conductive layer 126R on conductive layer 112R, and a conductive layer 129R on conductive layer 126R.

[0455] Light emitting device 130B has conductive layer 112B, conductive layer 126B on conductive layer 112B, and conductive layer 129B on conductive layer 126B.

[0456] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are made of a material that is highly transparent to visible light. The common electrode 155 is preferably made of a material that reflects visible light.

[0457] Although the light emitting device 130G is not shown in FIG. 14, the light emitting device 130G is also provided.

[0458] In addition, although FIG. 14 and other figures show an example in which the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited.

[0459] [Display device 100D2] The display device 100D2 shown in Fig. 23 is an example of a bottom emission type display device different from the display device 100D shown in Fig. 14. The display device 100D2 differs from the display device 100D in that it has an organic resin layer 180. Note that in the figure, the reference numerals of the same components as those in Fig. 14 may be omitted, and the description in Fig. 14 may be referred to for details.

[0460] 23(B) shows a top view layout of pixel 178 (pixel 178a and pixel 178b) having subpixel 110 (subpixel 110R, subpixel 110G, subpixel 110B, and subpixel 110W), and Fig. 23(C) shows a top view of organic resin layer 180 in a region where subpixel 110R and subpixel 110W of pixel 178 are formed. Note that the space between light-shielding layers 317 has a width 110Rw in the light-emitting region of subpixel 110R.

[0461] As shown in FIG. 23(A), the organic resin layer 180 is provided on the insulating layer 214. As shown in the region surrounded by the dashed line in FIG. 23(A) and in FIG. 23(C), the organic resin layer 180 has curved recesses 181 (recesses 181a and 181b) at least in the region where the subpixels are formed. The recesses 181 may be provided outside the light-emitting region, like the recess 181c. By providing the recess 181c, light emitted in the region overlapping with the light-shielding layer 317 or light traveling to the region overlapping with the light-shielding layer 317 is refracted and can be extracted from the light-emitting region, thereby improving the light-emitting efficiency.

[0462] A plurality of recesses 181 may be formed in a matrix. Recesses 181a and 181b may be provided in contact with each other, or may have a flat surface therebetween.

[0463] In addition, in Fig. 23, the upper surface shape of the recess is shown as a hexagon (Fig. 23(C)) and the cross-sectional shape is shown as a semicircle (Fig. 23(A)), but other shapes may be used as necessary. For example, the upper surface shape of the recess may be a polygon such as a triangle, a quadrangle (including a rectangle and a square), a pentagon, or the like, or a shape with rounded corners of such a polygon, an ellipse, or a circle.

[0464] An insulating layer having an organic material can be used as the organic resin layer 180. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be applied as the organic resin layer 180. In addition, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the organic resin layer 180.

[0465] Moreover, a photosensitive resin can be used as the organic resin layer 180. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive type material or a negative type material.

[0466] The organic resin layer 180 may contain a material that absorbs visible light. For example, the organic resin layer 180 itself may be made of a material that absorbs visible light, or the organic resin layer 180 may contain a pigment that absorbs visible light. As the organic resin layer 180, for example, a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix, can be used.

[0467] In addition, a first electrode 101 (a first electrode 101R and a first electrode 101W) is provided on the organic resin layer 180, and an EL layer 103 is provided on the first electrode 101. Ends of the first electrode 101 and the EL layer 103 may be covered with an insulating layer 127.

[0468] Moreover, the first electrode 101 formed on the organic resin layer 180 has a similar recess along the recess of the organic resin layer 180. Furthermore, the EL layer 103 formed on the first electrode 101 has a similar recess along the recess of the first electrode 101. Furthermore, the common layer 104 formed on the EL layer 103 has a similar recess along the recess of the EL layer 103. Furthermore, the second electrode 102 formed on the common layer 104 has a similar recess along the recess of the common layer 104. That is, the recesses of the organic resin layer 180, the first electrode 101, the EL layer 103, the common layer 104, and the second electrode 102 have a structure in which they overlap each other.

[0469] In addition, a common layer 104 is provided over the EL layer 103 and the insulating layer 127, and a second electrode 102 is provided over the common layer 104. A protective layer 131 is provided over the second electrode 102, and is attached to a substrate 352 via an adhesive layer 142.

[0470] Although light emitting device 130G and light emitting device 130B are not shown in FIG. 23, light emitting device 130G and light emitting device 130B are also provided.

[0471] The light-emitting device of one embodiment of the present invention having the above-described organic resin layer 180 includes an electron-injection layer as described in Embodiment 1, and therefore an organic semiconductor device with high reliability, low driving voltage, and low power consumption can be provided.

[0472] [Display device 100E] The display device 100E shown in FIG. 15 is a modification of the display device 100C shown in FIG. 13, and differs from the display device 100C mainly in that the display device 100E has colored layers 132R, 132G, and 132B.

[0473] In the display device 100E, the light emitting device 130 has an area overlapping one of the colored layer 132R, the colored layer 132G, and the colored layer 132B. The colored layer 132R, the colored layer 132G, and the colored layer 132B can be provided on the surface of the substrate 352 facing the substrate 351. An end of the colored layer 132R, an end of the colored layer 132G, and an end of the colored layer 132B can overlap the light blocking layer 157.

[0474] In the display device 100E, the light emitting device 130 can emit, for example, white light. For example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may be configured such that the colored layers 132R, 132G, and 132B are provided between the protective layer 131 and the adhesive layer 142.

[0475] Although an example in which the upper surface of the layer 128 has a flat portion is shown in FIG. 13 to FIG. 15 and the like, the shape of the layer 128 is not particularly limited.

[0476] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate.

[0477] [Display device 100E2] The display device 100E2 shown in Fig. 24 is a modified example of the display device 100E shown in Fig. 15, and has microlenses 182 on the colored layers 132R, 132G, and 132B. Note that in the drawing, the reference numerals of the same components as those in Fig. 15 may be omitted, and the description in Fig. 15 may be referred to for details.

[0478] 24(B) shows a top view layout of pixel 178 (pixels 178a and 178b) having subpixels 110 (subpixels 110R, 110G, and 110B), and Fig. 24(C) shows a top view of microlens 182 in a region where subpixels 110R and 110G of pixel 178 are formed. Note that the region where common electrode 155 and EL layer 103 contact in subpixel 110G has width 110Gw in the light-emitting region.

[0479] 24(A) has a planarization film 143 provided on a protective layer 131, and a colored layer 132R, a colored layer 132G, and a colored layer 132B provided on the planarization film 144. The planarization film 144 is provided so as to cover the colored layer 132R, the colored layer 132G, and the colored layer 132B. A microlens 182 is provided on the planarization film 144.

[0480] As shown in FIG. 24C, the microlens 182 may be provided for each sub-pixel in a region where the sub-pixels are formed.

[0481] 24(C), the top surface shape of the microlens 182 is shown as a hexagon, but other shapes may be used as necessary. For example, the top surface shape of the recess may be a polygon such as a triangle, a quadrangle (including a rectangle and a square), a pentagon, or the like, or a shape with rounded corners of such a polygon, an ellipse, or a circle.

[0482] The microlenses 182 can be formed using the same material as the organic resin layer 180 .

[0483] The light-emitting device of one embodiment of the present invention having the above-described microlens 182 includes an organic EL device having an electron-injection layer as described in Embodiment 1; therefore, an organic semiconductor device that is highly reliable, has a low driving voltage, and consumes low power, and is optimal for a mobile display can be provided.

[0484] (Embodiment 5) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0485] The electronic devices of this embodiment include the display device of one embodiment of the present invention in a display portion. The display device of one embodiment of the present invention has high display performance and can easily achieve high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portion of various electronic devices.

[0486] Examples of electronic devices include electronic devices with relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and audio playback devices.

[0487] In particular, the display device of one embodiment of the present invention can be suitably used in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices, glasses-type AR devices, and MR devices.

[0488] The electronic device of this embodiment may have a sensor (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0489] An example of a wearable device that can be worn on the head will be described with reference to FIGS. 16(A) to 16(D).

[0490] Electronic device 700A shown in FIG. 16(A) and electronic device 700B shown in FIG. 16(B) each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0491] The display device of one embodiment of the present invention can be applied to the display panel 751. Thus, the electronic device can be highly reliable.

[0492] Each of the electronic device 700A and the electronic device 700B can project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Since the optical member 753 has translucency, a user can see the image displayed in the display area superimposed on a transmitted image visually recognized through the optical member 753.

[0493] The electronic device 700A and the electronic device 700B may be provided with a camera capable of capturing an image of the front as an imaging unit. In addition, the electronic device 700A and the electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to the orientation in the display area 756.

[0494] The communication unit has a wireless communication device and can supply, for example, a video signal through the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential can be connected may be provided.

[0495] Furthermore, the electronic device 700A and the electronic device 700B are provided with a battery, which can be charged wirelessly and / or wired.

[0496] The housing 721 may be provided with a touch sensor module.

[0497] As the touch sensor module, various touch sensors can be applied. For example, various types of sensors can be adopted, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, or an optical type. In particular, it is preferable to apply a capacitance type or an optical type sensor to the touch sensor module.

[0498] Electronic device 800A shown in FIG. 16(C) and electronic device 800B shown in FIG. 16(D) each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0499] The display device of one embodiment of the present invention can be applied to the display portion 820. Thus, the electronic device can be made highly reliable.

[0500] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform three-dimensional display using parallax.

[0501] It is preferable that electronic device 800A and electronic device 800B each have a mechanism capable of adjusting the left-right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes.

[0502] The mounting portion 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head.

[0503] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. In addition, multiple cameras may be provided so as to be compatible with multiple angles of view, such as telephoto and wide angle.

[0504] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone.

[0505] The electronic device 800A and the electronic device 800B may each have an input terminal. The input terminal can be connected to a cable for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0506] The electronic device of one embodiment of the present invention may have a function of wireless communication with the earphone 750.

[0507] 16B includes an earphone unit 727. A part of a wiring connecting the earphone unit 727 and a control unit may be disposed inside the housing 721 or the attachment unit 723.

[0508] 16D includes an earphone unit 827. For example, the earphone unit 827 and the control unit 824 may be configured to be connected to each other by wire.

[0509] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type devices (such as the electronic device 700A and the electronic device 700B) and goggles-type devices (such as the electronic device 800A and the electronic device 800B) are suitable.

[0510] An electronic device 6500 shown in FIG. 17A is a portable information terminal that can be used as a smartphone.

[0511] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0512] The display device of one embodiment of the present invention can be applied to the display portion 6502. Therefore, the electronic device can be highly reliable.

[0513] FIG. 17B is a schematic cross-sectional view including the end portion of the housing 6501 on the microphone 6506 side.

[0514] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0515] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by an adhesive layer (not shown).

[0516] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and the folded back part is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0517] The display device of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. In addition, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0518] 17C shows an example of a television set. In a television set 7100, a display portion 7000 is incorporated in a housing 7171. Here, the housing 7171 is supported by a stand 7173.

[0519] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can be provided with high reliability.

[0520] A television set 7100 shown in FIG. 17C can be operated using an operation switch provided in a housing 7171 and a remote control 7151 provided separately.

[0521] 17D shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214. A display portion 7000 is incorporated in the housing 7211.

[0522] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can be provided with high reliability.

[0523] 17(E) and 17(F) show an example of digital signage.

[0524] 17E includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, an operation key (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0525] 17F shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0526] 17E and 17F, the display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can have high reliability.

[0527] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it catches people's attention, which can increase the advertising effect of, for example, advertisements.

[0528] Furthermore, as shown in FIGS. 17(E) and 17(F), it is preferable that the digital signage 7300 or the digital signage 7400 be capable of linking with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user via wireless communication.

[0529] The electronic devices shown in Figures 18(A) to 18(G) have a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0530] 18(A) to 18(G) have various functions, such as a function of displaying various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, time, etc., a function of controlling processing by various software (programs), a wireless communication function, a function of reading and processing a program or data recorded in a recording medium, etc.

[0531] The electronic devices shown in FIGS. 18A to 18G will be described in detail below.

[0532] FIG. 18A is a perspective view showing a mobile information terminal 9171. The mobile information terminal 9171 can be used as, for example, a smartphone. Note that the mobile information terminal 9171 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, or the like. The mobile information terminal 9171 can display text and image information on a plurality of surfaces thereof. FIG. 18A shows an example in which three icons 9050 are displayed. Information 9051 shown in a dashed rectangle can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notification of incoming e-mail, SNS, phone call, etc., the title of the e-mail or SNS, the sender's name, date and time, time, remaining battery level, radio wave intensity, and the like. Alternatively, the icon 9050, etc. may be displayed at the position where the information 9051 is displayed.

[0533] 18(B) is a perspective view of a mobile information terminal 9172. The mobile information terminal 9172 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9172 while the mobile information terminal 9172 is stored in a breast pocket of clothes.

[0534] 18C is a perspective view showing a tablet terminal 9173. The tablet terminal 9173 is capable of executing various applications such as mobile phone, e-mail, text browsing and creation, music playback, Internet communication, computer games, etc. The tablet terminal 9173 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front side of a housing 9000, operation keys 9005 as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0535] FIG. 18D is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and charging with another information terminal through a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0536] 18(E) to 18(G) are perspective views showing a foldable mobile information terminal 9201. FIG. 18(E) shows the mobile information terminal 9201 in an unfolded state, FIG. 18(G) shows the mobile information terminal 9201 in a folded state, and FIG. 18(F) shows a perspective view of a state in the middle of changing from one of FIG. 18(E) and FIG. 18(G) to the other. The mobile information terminal 9201 has excellent portability in a folded state, and has excellent viewability of a display due to a seamless wide display area in an unfolded state. A display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm to 150 mm.

[0537] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate. EXAMPLES

[0538] In this example, detailed manufacturing methods and characteristics of light-emitting device 1-1 and light-emitting device 1-2, which are light-emitting devices according to one embodiment of the present invention, and comparative light-emitting device 1, which is a comparative light-emitting device, are described. The structural formulae of main compounds used in this example are shown below.

[0539] [ka]

[0540] (Method of manufacturing light-emitting device 1-1) First, on a glass substrate, 100 nm of an alloy of silver, palladium and copper (APC: Ag-Pd-Cu) was laminated as a reflective electrode from the substrate side, and 50 nm of indium tin oxide containing silicon oxide (ITSO) was laminated as a transparent electrode by sputtering to form a first electrode 101 having a size of 2 mm x 2 mm. The transparent electrode functions as an anode, and is regarded as the first electrode 101 together with the reflective electrode.

[0541] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water and baked at 200° C. for 1 hour.

[0542] After that, about 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to 1 Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and the substrate was then allowed to cool for approximately 30 minutes.

[0543] Next, the substrate was fixed to a holder installed in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a material (OCHD-003) having a molecular weight of 672 and containing 4 or more fluorines and having electron accepting properties were co-deposited on the first electrode 101 by a deposition method to a thickness of 10 nm in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003).

[0544] On the hole injection layer 111, PCBBiF was deposited to a thickness of 100 nm to form a hole transport layer.

[0545] Subsequently, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9′-phenyl-9H,9′H-3,3′-bicarbazole (abbreviation: βNCCP) represented by the above structural formula (iii), and [2-d3-methylphenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: βNCCP) represented by the above structural formula (iv) were deposited on the first hole transport layer. A 40-nm thick light-emitting layer was formed by co-evaporating 8mpTP-4mDBtPBfpm and βNCCP (8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)) in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)).

[0546] After that, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (v) was evaporated to a thickness of 20 nm, and then 8mpTP-4mDBtPBfpm was evaporated to a thickness of 15 nm to form an electron transport layer.

[0547] After the formation of the electron transport layer, 8mpTP-4mDBtPBfpm, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) represented by the above structural formula (vi), and indium (In) were co-evaporated to a thickness of 5 nm in a volume ratio of 0.5:0.5:0.02 (=8mpTP-4mDBtPBfpm:Pyrrd-Phen:In) to form an electron injection layer.

[0548] Thereafter, silver (Ag) and magnesium (Mg) were co-evaporated to a volume ratio of 1:0.1 and a film thickness of 15 nm to form the second electrode 102. In addition, a 70 nm film of 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (vii) was formed on the second electrode 102 as a cap layer to improve the light extraction efficiency.

[0549] Next, in a glove box with a nitrogen atmosphere, the light-emitting device was sealed with a glass substrate to prevent it from being exposed to the atmosphere (a UV-curable sealant was applied around the element, UV was irradiated only onto the sealant so as not to irradiate the light-emitting device, and heat treatment was performed at 80°C under atmospheric pressure for 1 hour), thereby forming light-emitting device 1-1.

[0550] (Method of manufacturing light-emitting device 1-2) Light-emitting device 1-2 was fabricated in the same manner as light-emitting device 1-1, except that 8mpTP-4mDBtPBfpm in the electron injection layer of light-emitting device 1-1 was replaced with 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) represented by the above structural formula (viii), and an electron injection layer was formed by co-evaporating 11mDBtBPPnfpr, Pyrrd-Phen, and indium (In) to a thickness of 5 nm in a volume ratio of 0.5:0.5:0.02 (=11mDBtBPPnfpr:Pyrrd-Phen:In).

[0551] (Method of producing comparative light-emitting device 1) Comparative light-emitting device 1 was fabricated in the same manner as light-emitting device 1-1, except that 8mpTP-4mDBtPBfpm, Pyrrd-Phen, and In in the electron injection layer of light-emitting device 1-1 were replaced with 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) represented by the above structural formula (ix) and lithium oxide (Li2O), and an electron injection layer was formed by co-evaporating mPPhen2P and Li2O to a thickness of 5 nm at a volume ratio of 1:0.02 (=mPPhen2P:Li2O).

[0552] The device structures of light-emitting device 1-1, light-emitting device 1-2 and comparative light-emitting device 1 are shown below.

[0553] [Table 5]

[0554] [Table 6]

[0555] The LUMO levels of the second organic compounds, 8mpTP-4mDBtPBfpm and 11mDBtBPPnfpr, were -3.01 eV and -3.02 eV, respectively. The LUMO level of mPPhen2P was -2.71 eV. The LUMO level of the first organic compound, Pyrrd-Phen, was -2.55 eV. That is, the light-emitting device 1-1 and the light-emitting device 1-2 are light-emitting devices in which the LUMO level of the second organic compound is 0.20 eV or more lower than the LUMO level of the first organic compound, and the comparative light-emitting device 1 is a light-emitting device in which the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound, but the difference is less than 0.20 eV.

[0556] The LUMO level value was determined by cyclic voltammetry (CV) measurement.

[0557] In the cyclic voltammetry (CV) measurement, the LUMO level (E) was calculated based on the oxidation peak potential (Epa) and reduction peak potential (Epc) obtained by changing the potential of the working electrode relative to the reference electrode. In the measurement, the LUMO level was obtained from the negative potential scan. The scan rate in the measurement was 0.1 V / s.

[0558] Specifically, the standard redox potential (Eo) (=(Epa+Epc) / 2) was calculated from the oxidation peak potential (Epa) and reduction peak potential (Epc) obtained from the cyclic voltammogram of the material, and the LUMO level value (E) (=Ex-Eo) was calculated by subtracting it from the potential energy (Ex) relative to the vacuum level of the reference electrode.

[0559] Note that the above shows the case where a reversible redox wave is obtained, but when an irreversible redox wave is obtained, the value obtained by adding a certain value (0.1 eV) to the reduction peak potential (Epc) was assumed to be the oxidation peak potential (Epa), and the standard redox potential (Eo) was calculated to one decimal place.

[0560] The luminance-current density characteristics of light-emitting device 1-1, light-emitting device 1-2, and comparative light-emitting device 1 are shown in FIG. 25, the luminance-voltage characteristics in FIG. 26, the current efficiency-current density characteristics in FIG. 27, the current density-voltage characteristics in FIG. 28, and the electroluminescence spectra in FIG. 29.

[0561] As can be seen from Figures 25 to 29, light-emitting device 1-1 and light-emitting device 1-2, in which the LUMO level of the second organic compound is lower by 0.20 eV or more than the LUMO level of the first organic compound, are light-emitting devices that have a lower driving voltage than comparative light-emitting device 1 and exhibit excellent characteristics of emitting green light with high efficiency. EXAMPLES

[0562] In this example, detailed manufacturing methods and characteristics of light-emitting device 2-1 and light-emitting device 2-2, which are light-emitting devices according to one embodiment of the present invention, and comparative light-emitting device 2-1 and comparative light-emitting device 2-2 will be described. The structural formulae of main compounds used in this example are shown below.

[0563] [ka]

[0564] (Method of manufacturing light-emitting device 2-1) First, on a glass substrate, 100 nm of an alloy of silver, palladium and copper (APC: Ag-Pd-Cu) was laminated as a reflective electrode from the substrate side, and 50 nm of indium tin oxide containing silicon oxide (ITSO) was laminated as a transparent electrode by sputtering to form a first electrode 101 having a size of 2 mm x 2 mm. The transparent electrode functions as an anode, and is regarded as the first electrode 101 together with the reflective electrode.

[0565] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water and baked at 200° C. for 1 hour.

[0566] After that, about 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to 1 Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and the substrate was then allowed to cool for approximately 30 minutes.

[0567] Next, the substrate was fixed to a holder installed in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a material (OCHD-003) having a molecular weight of 672 and containing 4 or more fluorines and having electron accepting properties were co-deposited on the first electrode 101 by a deposition method to a thickness of 10 nm in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003).

[0568] On the hole injection layer 111, PCBBiF was deposited to a thickness of 100 nm to form a hole transport layer.

[0569] Subsequently, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9′-phenyl-9H,9′H-3,3′-bicarbazole (abbreviation: βNCCP) represented by the above structural formula (iii), and [2-d3-methylphenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: βNCCP) represented by the above structural formula (iv) were deposited on the first hole transport layer. A 40-nm thick light-emitting layer was formed by co-evaporating 8mpTP-4mDBtPBfpm and βNCCP (8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)) in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)).

[0570] After that, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (v) was evaporated to a thickness of 20 nm, and then 8mpTP-4mDBtPBfpm was evaporated to a thickness of 15 nm to form an electron transport layer.

[0571] After the formation of the electron transport layer, an electron injection layer was formed by co-evaporating 8mpTP-4mDBtPBfpm, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) represented by the above structural formula (vi), and indium oxide (In2O3) to a thickness of 5 nm in a volume ratio of 0.5:0.5:0.02 (=8mpTP-4mDBtPBfpm:Pyrrd-Phen:In2O3).

[0572] After this, the substrate on which the electron injection layer had been formed was removed from the vacuum deposition apparatus and exposed to the atmosphere. After that, using trimethylaluminum (TMA) as a precursor and water vapor as an oxidizing agent, aluminum oxide was deposited to a thickness of 30 nm by the ALD method, forming the aluminum oxide film as the first protective layer.

[0573] A second protective layer was formed by depositing molybdenum to a thickness of 50 nm on the first protective layer by sputtering.

[0574] After applying a photoresist onto the second protective layer, exposure and development were performed to process the EL layer so that it corresponded to each of the multiple first electrodes and each electrode was independent, with a 3 μm-wide slit formed 3.5 μm away from the end of the first electrode.

[0575] Specifically, the second protective layer was processed using an etching gas containing tetrafluoromethane (CF4), oxygen (O2) and helium (He), and an etching gas containing oxygen (O2) with the developed photoresist as a mask, and then the photoresist was removed and the first protective layer was processed using a basic chemical solution containing tetramethylammonium hydroxide (abbreviation: TMAH) with water as the solvent, and an etching gas containing fluoroform (CHF3) and helium (He). After this, the EL layer (electron injection layer, electron transport layer, light-emitting layer, hole transport layer and hole injection layer) was processed using an etching gas containing oxygen (O2).

[0576] After processing the EL layer, the second protective layer was removed using an etching gas containing tetrafluoromethane (CF4), oxygen (O2), and helium (He), and then the first protective layer was removed using an acidic mixed acid solution containing hydrofluoric acid in water as a solvent, exposing the top surface of the electron injection layer. -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and heat treatment was carried out at 100° C. for 1 hour in a heating chamber in the vacuum deposition apparatus.

[0577] Thereafter, silver (Ag) and magnesium (Mg) were co-evaporated to a volume ratio of 1:0.1 and a film thickness of 15 nm to form the second electrode 102. In addition, a 70 nm film of 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (vii) was formed on the second electrode 102 as a cap layer to improve the light extraction efficiency.

[0578] Next, in a glove box with a nitrogen atmosphere, the light-emitting device was sealed with a glass substrate to prevent it from being exposed to the atmosphere (a UV-curable sealant was applied around the element, UV was irradiated only onto the sealant so as not to irradiate the light-emitting device, and heat treatment was performed at 80°C under atmospheric pressure for 1 hour), forming light-emitting device 2-1.

[0579] (Method of manufacturing light-emitting device 2-2) Light-emitting device 2-2 was fabricated in the same manner as light-emitting device 2-1, except that 8mpTP-4mDBtPBfpm in the electron injection layer of light-emitting device 2-1 was replaced with 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) represented by the above structural formula (viii), and an electron injection layer was formed by co-evaporating 11mDBtBPPnfpr, pyrrd-phen, and indium oxide (In2O3) to a thickness of 5 nm in a volume ratio of 0.5:0.5:0.02 (=11mDBtBPPnfpr:pyrrd-phen:In2O3).

[0580] (Method of producing comparative light-emitting device 2-1) Comparative light-emitting device 2-1 was fabricated in the same manner as light-emitting device 2-1, except that the 8mpTP-4mDBtPBfpm, Pyrrd-Phen, and indium oxide (In2O3) in the electron injection layer of light-emitting device 2-1 were replaced with 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) represented by the above structural formula (ix) and lithium oxide (Li2O), and an electron injection layer was formed by co-evaporating mPPhen2P and lithium oxide (Li2O) to a thickness of 5 nm at a volume ratio of 1:0.02 (=mPPhen2P:Li2O).

[0581] (Method of producing comparative light-emitting device 2-2) Comparative light-emitting device 2-2 was fabricated in the same manner as light-emitting device 2-1, except that the 8mpTP-4mDBtPBfpm, pyrrd-phen, and indium oxide (In2O3) in the electron injection layer of light-emitting device 2-1 were replaced with 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), pyrrd-phen, and indium (In) represented by the above structural formula (x), and an electron injection layer was formed by co-evaporating αN-βNPAnth, pyrrd-phen, and indium (In) to a thickness of 5 nm so as to achieve a volume ratio of 0.5:0.5:0.02 (=αN-βNPAnth:pyrr-phen:in).

[0582] The device structures of light-emitting device 2-1, light-emitting device 2-2, comparative light-emitting device 2-1 and comparative light-emitting device 2-2 are shown below.

[0583] [Table 7]

[0584] [Table 8]

[0585] The LUMO levels of the second organic compounds 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr and αN-βNPAnth were -3.01 eV, -3.02 eV and -2.74 eV, respectively. The LUMO level of mPPhen2P was -2.71 eV. The LUMO level of the first organic compound Pyrrd-Phen was -2.55 eV. The values ​​of the LUMO levels were calculated by the method described in Example 1.

[0586] The luminance-current density characteristics of light-emitting device 2-1, light-emitting device 2-2, comparative light-emitting device 2-1, and comparative light-emitting device 2-2 are shown in Fig. 30, their luminance-voltage characteristics in Fig. 31, their current efficiency-current density characteristics in Fig. 32, their current density-voltage characteristics in Fig. 33, and their electroluminescence spectra in Fig. 34. The luminance and emission spectra were measured at room temperature using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation).

[0587] As can be seen from Figures 30 to 34, light-emitting device 2-1 and light-emitting device 2-2, in which the LUMO level of the second organic compound is 0.20 eV or more lower than the LUMO level of the first organic compound, are light-emitting devices that have a lower driving voltage than comparative light-emitting device 2-1 and comparative light-emitting device 2-2 and exhibit excellent characteristics of emitting green light with high efficiency.

[0588] In addition, light-emitting devices having the same laminate structure as light-emitting device 2-1, light-emitting device 2-2, comparative light-emitting device 2-1 and comparative light-emitting device 2-2, but not having undergone processing of the EL layer by photolithography, were fabricated, and a current density of 50 mA / cm 2The voltage difference at the first organic compound and the second organic compound was calculated. The voltage difference was plotted against the LUMO level of the second organic compound, and the result is shown in FIG. 35. It was found from FIG. 35 that a light-emitting device in which the LUMO level of the second organic compound is lower than 2.74 eV has good characteristics in which the increase in the driving voltage is suppressed even after processing by the photolithography method. Since the LUMO level of the first organic compound is -2.55 eV, it was found that a light-emitting device in which the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound by 0.20 eV or more has good characteristics in which the increase in the driving voltage is suppressed even after processing by the photolithography method. [Explanation of symbols]

[0589] 100A display device 100B display device 100C display device 100E display unit 100D display device 100 Insulator 101a first electrode 101b First electrode 101c first electrode 101d First electrode 101 First electrode 101R First electrode 101G First electrode 101B First electrode 102 Second electrode 103a EL layer 103B EL layer 103b EL layer 103Bf Organic compound film 103c EL layer 103d EL layer 103G EL layer 103Gf organic compound film 103R EL layer 103Rf Organic compound film 103 EL layer 110B subpixel 110G subpixel 110R subpixel 110 subpixels 111a Hole injection layer 111b Hole injection layer 111c Hole injection layer 111d Hole injection layer 111 Hole injection layer 112 Hole transport layer 112a Hole transport layer 112b Hole transport layer 112c_1 Hole transport layer 112c_2 Hole transport layer 112d_1 Hole transport layer 112d_2 Hole transport layer 112R conductive layer 112B Conductive layer 113 Light-emitting layer 113a Light-emitting layer 113b Light-emitting layer 113c_1 Emitting layer 113c_2 Emitting layer 113d_1 Light-emitting layer 113d_2 Emitting layer 114 Electron transport layer 114a Electron transport layer 114b Electron transport layer 114c_1 Electron transport layer 114c_2 Electron transport layer 114d_1 Electron transport layer 114d_2 Electron transport layer 115 Electron injection layer 115a Electron injection layer 115b Electron injection layer 115c Electron injection layer 115d Electron injection layer 116 Middle Class 116c middle class 116d middle class 117 P type layer 117c P type layer 117d P type layer 118 Electronic Relay Layer 118c Electronic Relay Layer 118d Electronic Relay Layer 119 N-type layer 119c N-type layer 119d N-type layer 120 Substrate 122 Resin layer 125f Inorganic insulating film 125 Inorganic insulating layer 126R conductive layer 126B Conductive layer 127a Insulating layer 127f Insulating film 127 Insulating Layer 128 layers 129R conductive layer 129B Conductive layer 130a Light emitting device 130B Light Emitting Device 130b Light emitting device 130c Light Emitting Device 130d Light-emitting device 130G Light Emitting Device 130R Light Emitting Device 130 Light Emitting Devices 131 Protective layer 132B Colored layer 132G colored layer 132R colored layer 140 Connection 141 areas 142 Adhesive layer 151B Conductive layer 151C conductive layer 151f Conductive film 151G conductive layer 151R conductive layer 151 Conductive layer 152B Conductive layer 152C conductive layer 152f Conductive film 152G Conductive layer 152R Conductive layer 152 Conductive layer 153 Insulating Layer 155 Common electrode 156B Insulating layer 156C Insulating layer 156f Insulating film 156G Insulation layer 156R Insulation layer 156 Insulating Layer 157 Light blocking layer 158B Sacrificial Layer 158Bf sacrificial film 158G ...

Claims

1. A first electrode, a second electrode, and an EL layer, the EL layer is located between the first electrode and the second electrode; The EL layer has a light-emitting layer and an electron injection layer, the electron injection layer is a mixed layer containing a metal or an oxide of the metal, a first organic compound, and a second organic compound; the first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound having a second π-electron deficient heteroaromatic ring, A light-emitting device, wherein the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound by 0.20 eV or more.

2. a first group of electrodes formed on the same insulating surface; a second electrode group facing the first electrode group; a light-emitting device among a plurality of light-emitting devices included in a light-emitting device group having an EL layer group located between the first electrode group and the second electrode group, The light emitting device comprises: A first electrode, a second electrode, and an EL layer, The first electrode is one of the first electrode group, the first electrode is independent for each of the plurality of light emitting devices; The EL layer is one of the EL layers, The EL layer is independent for each of the plurality of light-emitting devices, the second electrode being a continuous conductive layer shared by the plurality of light emitting devices; the second electrode and the EL layer overlap the first electrode; The EL layer has a light-emitting layer and an electron injection layer, the electron injection layer is a mixed layer containing a metal or an oxide of the metal, a first organic compound, and a second organic compound; the first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound having a second π-electron deficient heteroaromatic ring, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound by 0.20 eV or more; A light-emitting device, wherein the distance between the EL layer of the light-emitting device and an EL layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

3. A first electrode, a second electrode, and an EL layer, the EL layer is located between the first electrode and the second electrode; The EL layer has a light-emitting layer and an electron injection layer, the electron injection layer has a laminated structure of a first layer containing a metal and a second layer containing a first organic compound and a second organic compound; the first layer is located closer to the cathode than the second layer; the first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound having a second π-electron deficient heteroaromatic ring, A light-emitting device, wherein the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound by 0.20 eV or more.

4. a first group of electrodes formed on the same insulating surface; a second electrode group facing the first electrode group; a light-emitting device among a plurality of light-emitting devices included in a light-emitting device group having an EL layer group located between the first electrode group and the second electrode group, The light emitting device comprises: A first electrode, a second electrode, and an EL layer, The first electrode is one of the first electrode group, the first electrode is independent for each of the plurality of light emitting devices; The EL layer is one of the EL layers, The EL layer is independent for each of the plurality of light-emitting devices, the second electrode being a continuous conductive layer shared by the plurality of light emitting devices; the second electrode and the EL layer overlap the first electrode; The EL layer has a light-emitting layer and an electron injection layer, the electron injection layer has a laminated structure of a first layer containing a metal and a second layer containing a first organic compound and a second organic compound; the first layer is located closer to the cathode than the second layer; the first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound having a second π-electron deficient heteroaromatic ring, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound by 0.20 eV or more; A light-emitting device, wherein the distance between the EL layer of the light-emitting device and an EL layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

5. In claim 1 or 2, When the LUMO level of the first organic compound is LUMO1 (eV), the LUMO level of the second organic compound (LUMO2 (eV)) is LUMO1-0.80≦LUMO2≦LUMO1-0.20 Meet the light-emitting devices.

6. In claim 1 or 2, A light-emitting device, wherein the first π-electron deficient heteroaromatic ring is a heteroaromatic ring that includes two or more pyridine rings.

7. In claim 1 or 2, A light-emitting device, wherein the first organic compound is an organic compound having an acid dissociation constant pKa of 8 or more.

8. In claim 1 or 2, A light emitting device, wherein the first π-electron deficient heteroaromatic ring and the second π-electron deficient heteroaromatic ring are different.

9. In claim 1 or 2, A light-emitting device, wherein the second organic compound has an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), a triazole ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), or a triazine ring.

10. In claim 1 or 2, The second organic compound has an acid dissociation constant pKa of less than 4.

11. In claim 1 or 2, the light-emitting layer includes a third organic compound, The third organic compound has a third π-electron deficient heteroaromatic ring. A light-emitting device, wherein the third pi-electron deficient heteroaromatic ring is the same as the second pi-electron deficient heteroaromatic ring.

12. In claim 1 or 2, the light-emitting layer includes a third organic compound, The light-emitting device, wherein the third organic compound is the same organic compound as the second organic compound.

13. In claim 1 or 2, an electron transport layer between the light emitting layer and the electron injection layer; the electron transport layer comprises a fourth organic compound, The fourth organic compound is a different organic compound than the third organic compound.

14. In claim 1 or 2, A light-emitting device, wherein the metal is a metal of Group 3, Group 11, or Group 13 of the periodic table.

15. In claim 1 or 2, The electron donating group is The light emitting device may include one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

16. In claim 1 or 2, The minimum value of the electrostatic potential of the first organic compound is a threshold value of the electron density distribution of 0.0004 e / a in atomic units. ０ ３ In the case where ｈ 2. A light emitting device, comprising:

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