Composite materials for hole injection layers

Abstract

The present invention provides a composite material with a low refractive index that can be used in optical devices such as light-emitting devices, light-receiving devices, and light-receiving / light-emitting devices. [Solution] The present invention relates to a composite material comprising a first organic compound and a second organic compound, wherein the proportion of carbon atoms in the first organic compound that form bonds via sp3 hybrid orbitals relative to the total number of carbon atoms is 23% to 55%, and the second organic compound contains fluorine. The present invention also relates to an optical device comprising an anode, a cathode, and a first layer, wherein the first layer contains the composite material.

Description

[Technical Field]

[0001] One aspect of the present invention relates to composite materials such as composite materials for hole injection layers, composite materials for hole transport layers, and composite materials for charge generation layers. One aspect of the present invention relates to optical devices such as light-emitting devices, light-receiving devices, and light-receiving / receiving devices. One aspect of the present invention relates to devices such as light-emitting devices, light-receiving devices, and light-receiving / receiving devices. One aspect of the present invention relates to modules such as light-emitting modules, light-receiving modules, light-receiving / receiving modules, display modules, and lighting modules. One aspect of the present invention relates to electronic devices and lighting devices.

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

[0003] Research and development of light-emitting devices (also called organic EL devices or organic EL elements) that utilize the organic electroluminescence (EL) phenomenon are actively underway. The basic structure of an organic EL device is a layer containing a light-emitting organic compound (hereinafter also referred to as the light-emitting layer) sandwiched between a pair of electrodes. By applying a voltage to this organic EL device, light emission can be obtained from the light-emitting organic compound.

[0004] Organic EL devices are suitable for display devices because they are easy to make thin and light, can respond quickly to input signals, and can be driven using a DC constant voltage power supply.

[0005] Furthermore, because organic EL devices can be formed in a film-like structure, they can emit light in a planar manner. Therefore, large-area light-emitting devices can be easily formed. This is a feature that is difficult to obtain with point light sources such as LEDs (light-emitting diodes) and line light sources such as fluorescent lamps, and therefore organic EL devices have high utility as planar light sources that can be applied to lighting devices and the like.

[0006] Further improvements in light extraction efficiency are required for organic EL devices. Light attenuation due to reflection caused by differences in refractive index between adjacent layers is one of the factors that reduces light extraction efficiency. In organic EL devices, light extraction efficiency can be improved by using materials with a low refractive index. For example, Non-Patent Document 1 discloses an organic EL device having a layer with a low refractive index.

[0007] On the other hand, it is difficult to achieve both a low refractive index and high reliability or high heat resistance in materials used for organic EL devices. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 0176692 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] One aspect of the present invention aims to provide a novel composite material that can be used in light-emitting devices, light-receiving devices, light-receiving and light-emitting devices, etc. One aspect of the present invention aims to provide a composite material with a low refractive index that can be used in light-emitting devices, light-receiving devices, light-receiving and light-emitting devices, etc. One aspect of the present invention aims to provide a composite material with high heat resistance that can be used in light-emitting devices, light-receiving devices, light-receiving and light-emitting devices, etc. One aspect of the present invention aims to provide a novel composite material for a hole injection layer, a composite material for a hole transport layer, or a composite material for a charge generation layer. One aspect of the present invention aims to provide a composite material for a hole injection layer, a composite material for a hole transport layer, or a composite material for a charge generation layer that has a low refractive index. One aspect of the present invention aims to provide a composite material for a hole injection layer, a composite material for a hole transport layer, or a composite material for a charge generation layer that contains a highly heat-resistant organic compound and has a low refractive index.

[0010] One aspect of the present invention aims to provide a light-emitting device or a light-receiving device with high luminous efficiency. One aspect of the present invention aims to provide a light-emitting device or a light-receiving device with high light extraction efficiency. One aspect of the present invention aims to provide a light-emitting device, a light-receiving device or a light-receiving device with high heat resistance. One aspect of the present invention aims to provide a light-emitting device, a light-receiving device or a light-receiving device with a long lifespan. One aspect of the present invention aims to provide a light-emitting device, a light-receiving device or a light-receiving device with low power consumption.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. One aspect of the present invention does not necessarily have to solve all of these problems. It is possible to extract other problems from the description in the specification, drawings, and claims. [Means for solving the problem]

[0012] One aspect of the present invention is a composite material comprising a first organic compound and a second organic compound, wherein the proportion of carbon atoms in the first organic compound that form bonds via sp3 hybrid orbitals relative to the total number of carbon atoms is 23% to 55%, and the second organic compound contains fluorine. Preferably, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 to 1.70.

[0013] One aspect of the present invention is a composite material comprising a first organic compound and a second organic compound, wherein the glass transition temperature of the first organic compound is 90°C or higher, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 or higher and 1.70 or lower, and the second organic compound is fluorine-containing.

[0014] The first organic compound is preferably an amine compound, and more preferably a monoamine compound.

[0015] One aspect of the present invention is a composite material comprising a first organic compound and a second organic compound, wherein the first organic compound is a monoamine compound, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 or more and 1.70 or less, and the second organic compound is fluorine-containing.

[0016] The molecular weight of the first organic compound is preferably between 650 and 1200.

[0017] The first organic compound is preferably a triaryl monoamine compound.

[0018] First organic compound 1 In 1H-NMR measurement results, it is preferable that the integrated value of signals below 4 ppm is greater than the integrated value of signals above 4 ppm.

[0019] The first organic compound preferably has at least one hydrocarbon group having 1 to 12 carbon atoms.

[0020] The first organic compound preferably has at least one of an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms.

[0021] The second organic compound preferably contains a cyano group.

[0022] The LUMO level of the second organic compound is preferably -5.0 eV or lower.

[0023] The second organic compound preferably exhibits electron-accepting properties toward the first organic compound.

[0024] One aspect of the present invention is an optical device having a composite material having any of the above configurations. Examples of optical devices include light-emitting devices, light-receiving devices, or light-receiving / receiving devices. The composite material according to one aspect of the present invention can be used in hole injection layers, hole transport layers, or charge generation layers, etc.

[0025] One aspect of the present invention is an optical device comprising an anode, a cathode, and a first layer, wherein the first layer comprises a first organic compound and a second organic compound, the ratio of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms of the first organic compound being 23% or more and 55% or less, and the second organic compound containing fluorine. Preferably, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0026] One aspect of the present invention is an optical device comprising an anode, a cathode, and a first layer, wherein the first layer comprises a first organic compound and a second organic compound, the glass transition temperature of the first organic compound is 90°C or higher, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 or higher and 1.70 or lower, and the second organic compound contains fluorine.

[0027] One aspect of the present invention is an optical device comprising an anode, a cathode, and a first layer, wherein the first layer comprises a first organic compound and a second organic compound, the first organic compound being a monoamine compound, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm being 1.45 or more and 1.70 or less, and the second organic compound containing fluorine.

[0028] The optical device with any of the above configurations further preferably has a second layer, the second layer being located between the first layer and the cathode, and the second layer preferably having a first organic compound. The second layer is preferably in contact with the first layer.

[0029] In any of the above configurations of optical devices, the first layer is preferably in contact with the anode.

[0030] Alternatively, the optical device having any of the above configurations further comprises a first light-emitting layer and a second light-emitting layer, wherein the first layer is preferably located between the first light-emitting layer and the second light-emitting layer.

[0031] One aspect of the present invention is an apparatus comprising an optical device with any of the above configurations, and at least one of a transistor and a substrate.

[0032] One aspect of the present invention is a module comprising the above-described device and at least one of a connector and an integrated circuit (IC). Examples of connectors include flexible printed circuit boards (FPCs) and TCPs (Tape Carrier Packages). The IC can be mounted on the device using methods such as COG (Chip On Glass) or COF (Chip On Film). The module according to one aspect of the present invention may have only one of the connector and the IC, or it may have both.

[0033] One aspect of the present invention is an electronic device having the above-mentioned device and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

[0034] One aspect of the present invention is a lighting device comprising an optical device with any of the above configurations, and at least one of a housing, a cover, and a support base, wherein the optical device is a light-emitting device. [Effects of the Invention]

[0035] According to one aspect of the present invention, a novel composite material can be provided that can be used in light-emitting devices, light-receiving devices, light-receiving and light-emitting devices, etc. According to one aspect of the present invention, a composite material with a low refractive index can be provided that can be used in light-emitting devices, light-receiving devices, light-receiving and light-emitting devices, etc. According to one aspect of the present invention, a composite material with high heat resistance can be provided that can be used in light-emitting devices, light-receiving devices, light-receiving and light-emitting devices, etc. According to one aspect of the present invention, a novel composite material for a hole transport layer, a composite material for a hole injection layer, or a composite material for a charge generation layer can be provided. According to one aspect of the present invention, a composite material for a hole transport layer, a composite material for a hole injection layer, or a composite material for a charge generation layer can be provided that has a low refractive index. According to one aspect of the present invention, a composite material for a hole transport layer, a composite material for a hole injection layer, or a composite material for a charge generation layer can be provided that contains a highly heat-resistant organic compound and has a low refractive index.

[0036] According to one aspect of the present invention, a light-emitting device or a light-receiving device with high luminous efficiency can be provided. According to one aspect of the present invention, a light-emitting device or a light-receiving device with high light extraction efficiency can be provided. According to one aspect of the present invention, a light-emitting device, a light-receiving device or a light-receiving device with high heat resistance can be provided. According to one aspect of the present invention, a light-emitting device, a light-receiving device or a light-receiving device with a long lifespan can be provided. According to one aspect of the present invention, a light-emitting device, a light-receiving device or a light-receiving device with low power consumption can be provided.

[0037] Furthermore, the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to possess all of these effects. Other effects can be extracted from the description, drawings, and claims. [Brief explanation of the drawing]

[0038] [Figure 1] Figures 1A to 1D are cross-sectional views showing an example of a light-emitting device. [Figure 2] Figure 2A is a top view showing an example of a light-emitting device. Figures 2B and 2C are cross-sectional views showing an example of a light-emitting device. [Figure 3] Figures 3A and 3C are cross-sectional views showing an example of a light-emitting device. Figure 3B is a cross-sectional view showing an example of a light-emitting device. [Figure 4] Figures 4A and 4B are cross-sectional views showing an example of a light-emitting device. [Figure 5] Figure 5A is a top view showing an example of a light-emitting device. Figure 5B is a cross-sectional view showing an example of a light-emitting device. Figures 5C and 5D are cross-sectional views showing an example of a transistor. [Figure 6] Figures 6A and 6B are cross-sectional views showing an example of a light-receiving device. Figures 6C and 6D are diagrams showing an example of a light-receiving device. [Figure 7] Figures 7A to 7C show examples of display devices. [Figure 8] Figures 8A to 8D show examples of electronic devices. [Figure 9] Figures 9A to 9F show examples of electronic devices. [Figure 10] Figures 10A to 10C show examples of automobiles. [Figure 11] Figures 11A to 11E show examples of electronic devices. [Figure 12] Figure 12 is a cross-sectional view showing the light-emitting device of an embodiment. [Figure 13] Figure 13 shows the measurement results of the refractive index of dchPAF and PCBBiF. [Figure 14]Figure 14 shows the brightness-current density characteristics of the light-emitting device of Example 1. [Figure 15] Figure 15 shows the current efficiency-luminance characteristics of the light-emitting device of Example 1. [Figure 16] Figure 16 shows the current-voltage characteristics of the light-emitting device of Example 1. [Figure 17] Figure 17 shows the external quantum efficiency-luminance characteristics of the light-emitting device of Example 1. [Figure 18] Figure 18 shows the emission spectrum of the light-emitting device of Example 1. [Figure 19] Figure 19 shows the results of the reliability test of the light-emitting device in Example 1. [Figure 20] Figure 20 shows the measurement results of the refractive index of mmtBumTPchPAF and PCBBiF. [Figure 21] Figure 21 shows the brightness-current density characteristics of the light-emitting device of Example 2. [Figure 22] Figure 22 shows the current efficiency-luminance characteristics of the light-emitting device of Example 2. [Figure 23] Figure 23 shows the current-voltage characteristics of the light-emitting device in Example 2. [Figure 24] Figure 24 shows the external quantum efficiency-luminance characteristics of the light-emitting device of Example 2. [Figure 25] Figure 25 shows the emission spectrum of the light-emitting device of Example 2. [Figure 26] Figure 26 shows the results of the reliability test of the light-emitting device in Example 2. [Modes for carrying out the invention]

[0039] Embodiments will be described in detail with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be construed as being limited to the descriptions of the embodiments shown below.

[0040] In the configuration of the invention described below, the same reference numerals are used in common across different drawings for identical parts or parts having similar functions, and repeated explanations are omitted. Furthermore, when referring to similar functions, the hatch patterns are the same, and reference numerals may not be assigned.

[0041] Furthermore, for the sake of ease of understanding, the position, size, and scope of each component shown in the drawings may not represent their actual position, size, and scope. Therefore, the disclosed invention is not necessarily limited to the position, size, and scope disclosed in the drawings.

[0042] It should be noted that the terms "film" and "layer" can be interchanged depending on the context or situation. For example, the term "conductive layer" can be changed to "conductive film." Or, for example, the term "insulating film" can be changed to "insulating layer."

[0043] (Embodiment 1) This embodiment describes a composite material according to one aspect of the present invention.

[0044] A composite material according to one aspect of the present invention can be used in light-emitting devices such as organic EL devices, in applications such as hole injection layers, hole transport layers, and charge generation layers.

[0045] A composite material according to one aspect of the present invention can be used as a carrier transport material (hole transport material) in light-receiving devices such as organic photodiodes, and light-emitting and light-receiving devices having both light-emitting and light-receiving functions.

[0046] For example, in organic EL devices, the hole injection layer and charge generation layer can be made of a composite material containing a hole-transporting material and a material that accepts electrons for the hole-transporting material, respectively. For these layers to have hole injection or charge generation functions, interactions must occur between the materials constituting the composite material, and a charge transfer complex must be formed.

[0047] Here, if the composite material contains a large amount of electron-accepting material, absorption of light in the visible region may occur, potentially reducing the luminous efficiency of the organic EL device. Therefore, it is preferable for the composite material to contain a larger amount of hole-transporting material than electron-accepting material. For example, in one embodiment of the present invention, a composite material can be configured in which a small amount of electron-accepting material is added to the hole-transporting material.

[0048] Furthermore, lowering the refractive index of the materials used in organic EL devices can increase the external quantum efficiency, so a low refractive index of the composite material is desirable. This can be achieved by lowering the refractive index of the hole transport material, which makes up the majority of the composite material.

[0049] To obtain a material with a low refractive index, it is preferable to introduce substituents with low atomic refraction into the molecule. Examples of such substituents include chain-type saturated hydrocarbon groups and cyclic saturated hydrocarbon groups. However, these substituents hinder interaction with electron-accepting materials. Therefore, it is difficult to achieve both ease of interaction with electron-accepting materials and a low refractive index in hole-transporting materials. Furthermore, these substituents also hinder the expression of carrier transport properties. Therefore, it is difficult to achieve both high carrier transport properties and a low refractive index in layers containing composite materials.

[0050] Furthermore, to improve the reliability of organic EL devices, it is desirable for the materials used in organic EL devices to have a high glass transition temperature (Tg). Increasing the glass transition temperature requires increasing the molecular weight of the material. One method for obtaining a highly heat-resistant and reliable hole-transporting material is to introduce unsaturated hydrocarbon groups, particularly cyclic unsaturated hydrocarbon groups, into the molecule. However, introducing a skeleton with unsaturated bonds into the molecule to increase the molecular weight increases the refractive index of the material. Thus, it is difficult to achieve both a high glass transition temperature and a low refractive index in hole-transporting materials. Moreover, introducing a skeleton with saturated bonds to increase the molecular weight further suppresses the interaction with electron-accepting materials.

[0051] Among hole transport materials that can be used in organic EL devices, 1,1-bis-(4-bis(4-methylphenyl)-aminophenyl)cyclohexane (abbreviated as TAPC) is known as one of the materials with a low refractive index. It is expected that light-emitting devices with good external quantum efficiency can be obtained by using TAPC.

[0052] Typically, there is a trade-off between high carrier transport and low refractive index. This is because carrier transport in organic compounds largely depends on the presence of unsaturated bonds, and organic compounds with many unsaturated bonds tend to have high refractive indices. TAPC is a substance that achieves a delicate balance between carrier transport and low refractive index. On the other hand, in compounds like TAPC, which have a 1,1-disubstituted structure of cyclohexane, the insertion of two bulky substituents on one carbon of cyclohexane results in high steric repulsion, inducing instability in the molecule itself, which is unfavorable from a reliability standpoint. Furthermore, due to its skeleton consisting of cyclohexane and a simple benzene ring, TAPC has a low glass transition temperature of 85°C, resulting in problems with heat resistance.

[0053] As described above, it is not easy to improve the glass transition temperature to enhance heat resistance and reliability during operation in hole-transporting materials while simultaneously possessing ease of interaction with electron-accepting materials, high carrier transport properties, and a low refractive index. To overcome these trade-offs, the inventors have discovered an organic compound with a high glass transition temperature and a certain percentage of carbon atoms forming bonds in sp3 hybrid orbitals. Furthermore, they have found that composite materials containing such organic compounds are useful as composite materials for hole injection layers, hole transport layers, and charge generation layers.

[0054] Specifically, one aspect of the present invention is a composite material comprising a first organic compound and a second organic compound, wherein the ratio of the number of carbon atoms in the first organic compound that form bonds with sp3 hybrid orbitals to the total number of carbon atoms is 23% or more and 55% or less, and the second organic compound contains fluorine.

[0055] Alternatively, one aspect of the present invention is a composite material comprising a first organic compound and a second organic compound, wherein the glass transition temperature of the first organic compound is 90°C or higher, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 or higher and 1.70 or lower, and the second organic compound is fluorine-containing.

[0056] Alternatively, one aspect of the present invention is a composite material comprising a first organic compound and a second organic compound, wherein the first organic compound is a monoamine compound, the refractive index of the layer made of the first organic compound at a wavelength of 633 nm is 1.45 or more and 1.70 or less, and the second organic compound is fluorine-containing.

[0057] These composite materials can be used as composite materials for hole transport layers, hole injection layers, charge generation layers, and the like.

[0058] [First organic compound] The proportion of carbon atoms in the first organic compound that form bonds via sp3 hybrid orbitals relative to the total number of carbon atoms is preferably 23% to 55%. Substituents composed of carbon atoms that form bonds via sp3 hybrid orbitals are so-called chain-type saturated hydrocarbon groups or cyclic saturated hydrocarbon groups, and therefore have low atomic refractions. As a result, the refractive index of the first organic compound can be lowered, and the refractive index of the composite material can also be reduced.

[0059] The glass transition temperature of the first organic compound is preferably 90°C or higher, more preferably 95°C or higher, more preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher.

[0060] The first organic compound, by having a cyclic saturated hydrocarbon group or a rigid tertiary hydrocarbon group, can maintain a high glass transition temperature and become a highly heat-resistant material. Generally, introducing saturated hydrocarbon groups, especially chain-type saturated hydrocarbon groups, tends to lower the glass transition temperature and melting point of the compound compared to the corresponding aromatic group or heteroaromatic group (e.g., with the same number of carbon atoms). A lower glass transition temperature can reduce the heat resistance of the organic EL material. Since it is desirable for various devices using organic EL materials to exhibit stable physical properties under various environments in human life, a high glass transition temperature is preferable for materials exhibiting equivalent properties.

[0061] The refractive index of the layer made of the first organic compound at a wavelength of 633 nm is preferably between 1.45 and 1.70. Note that 633 nm is a wavelength commonly used for measuring refractive index. Furthermore, the refractive index of the layer made of the first organic compound at wavelengths in the blue emission region (455 nm to 465 nm) is preferably between 1.50 and 1.75. Note that if anisotropy occurs in the material, the refractive index for ordinary light and the refractive index for extraordinary light may differ. In this case, by performing anisotropy analysis, the refractive index can be separated into ordinary and extraordinary refractive indices and their respective refractive indices can be calculated. In this specification, if both ordinary and extraordinary refractive indices exist in the measured material, the ordinary refractive index is used as the index.

[0062] Furthermore, the refractive index of the layer made of the first organic compound may be evaluated using the refractive index at the peak wavelength of light emitted by the light-emitting device using the first organic compound or at the emission peak wavelength of the light-emitting substance contained in the light-emitting device. In this case as well, the refractive index of the layer made of the first organic compound is preferably 1.50 or more and 1.75 or less, or 1.45 or more and 1.70 or less. The peak wavelength of light emitted by the light-emitting device is the peak wavelength of light before passing through the structure, if a structure that adjusts the light, such as a color filter, is provided. The emission peak wavelength of the light-emitting substance is calculated using the PL spectrum in solution. Since the relative permittivity of the organic compound constituting the EL layer of the light-emitting device is about 3, in order to avoid discrepancies with the emission spectrum of the light-emitting device, the relative permittivity of the solvent used to put the light-emitting center material into a solution is preferably 1 or more and 10 or less at room temperature, and more preferably 2 or more and 5 or less. Specific examples of such solutions include hexane, benzene, toluene, diethyl ether, ethyl acetate, chloroform, chlorobenzene, and dichloromethane. Furthermore, a solvent with a dielectric constant of 2 to 5 at room temperature, high solubility, and general-purpose properties is more preferable; for example, toluene or chloroform is preferred as the solution.

[0063] The first organic compound is preferably an amine compound, more preferably a monoamine compound, and even more preferably a triaryl monoamine compound.

[0064] It is preferable that the first organic compound is an amine compound because the highest occupied orbital (HOMO) level can be easily controlled to a desired height depending on the substitution position of the alkyl group.

[0065] The first organic compound preferably has an alkyl group bonded to the same plane as or near the plane forming the HOMO. In other words, it is preferable to position the alkyl group in a location where the HOMO is not obstructed. When the first organic compound is an aromatic amine compound, the plane forming the HOMO can be the plane of the aromatic ring to which the nitrogen is bonded. The alkyl group is preferably a tert-butyl group or a cyclohexyl group.

[0066] The first organic compound preferably has an alkyl group that functions as an electron-donating group at a bond position that further destabilizes the HOMO energy. For example, it is preferable to have an alkyl group at the para position of the nitrogen atom of triphenylamine. This makes it possible to raise (shallow) the HOMO energy level of the first organic compound.

[0067] The first organic compound preferably has a skeleton with high carrier transport properties, and among these, an aromatic amine skeleton is a preferred skeleton with high hole transport properties. To further improve carrier transport properties, it is also possible to introduce two amine skeletons. However, as with TAPC mentioned above, depending on the substituents arranged around it, the diamine structure may have unfavorable effects on reliability.

[0068] Overcoming trade-offs, the inventors have discovered a monoamine compound in which the proportion of carbon atoms forming bonds in sp3 hybrid orbitals is within a certain range, possessing a combination of ease of interaction with electron-accepting materials, high carrier transport properties, low refractive index, and high reliability. In particular, this monoamine compound is a material with good reliability comparable to conventional hole-transporting materials with normal refractive indices. Furthermore, by optimizing either the number of substituents or the substitution positions of substituents (alkyl groups and cycloalkyl groups, etc.) having carbon atoms forming bonds in sp3 hybrid orbitals, or both, a material with even better properties can be obtained. In monoamine compounds, the stability of the molecule can be improved by limiting the number of aromatic groups bonded to saturated hydrocarbon groups and reducing steric repulsion. As a result, optical devices with a good lifetime can be obtained.

[0069] The molecular weight of the first organic compound is preferably between 650 and 1200. This enhances the heat resistance of the first organic compound.

[0070] First organic compound 1 In 1H-NMR measurement results, it is preferable that the integrated value of signals below 4 ppm is greater than the integrated value of signals above 4 ppm.

[0071] Signals below 4 ppm reflect hydrogen in chain or cyclic saturated hydrocarbon groups, and if this is greater than the integral value of signals above 4 ppm, it means that the number of hydrogen atoms constituting the saturated hydrocarbon group is greater than the number of hydrogen atoms constituting the unsaturated hydrocarbon group. From this, the proportion of sp3 carbons in the molecule can be estimated. Here, the carbons in unsaturated hydrocarbon groups have fewer bonds that can bond with hydrogen; for example, comparing benzene and cyclohexane, C6H6 and C6H 12 There is a difference. When this difference is taken into account, 1The fact that the integrated value of signals below 4 ppm, as measured by 1H-NMR, is greater than the integrated value of signals above 4 ppm indicates that approximately one-third of the carbon atoms constituting the molecule are involved in saturated hydrocarbon groups. As a result, the first organic compound is an organic compound with a low refractive index and can be suitably used as a hole transport material and composite material.

[0072] An example of the first organic compound is a monoamine compound having a first aromatic group, a second aromatic group, and a third aromatic group, wherein the first, second, and third aromatic groups are directly bonded to the same nitrogen atom.

[0073] Monoamine compounds are preferable if they have at least one fluorene skeleton, as this improves hole transport properties. Therefore, it is preferable that one or more of the first, second, and third aromatic groups described above are fluorene skeletons. Furthermore, the direct bonding of the fluorene skeleton to the nitrogen atom of the amine contributes to raising the HOMO level of the molecule, thereby facilitating hole transfer.

[0074] The first aromatic group and the second aromatic group each independently have 1 to 3 benzene rings. Furthermore, it is preferable that both the first and second aromatic groups are hydrocarbon groups. Specifically, it is preferable that the first and second aromatic groups are phenyl, biphenyl, terphenyl, or naphthylphenyl groups, respectively. It is preferable that either the first or second aromatic group is a terphenyl group, as this improves the glass transition temperature and results in good heat resistance.

[0075] When the first aromatic group and the second aromatic group each have two or three benzene rings, it is preferable that these two or three benzene rings are bonded to each other. Furthermore, it is preferable that one or both of the first and second aromatic groups are substituents in which two or three benzene rings are bonded to each other, i.e., biphenyl groups or terphenyl groups, because this improves the glass transition temperature and improves heat resistance. It is even more preferable that the first and second aromatic groups are independently biphenyl groups or terphenyl groups.

[0076] Furthermore, it is preferable that one or both of the first aromatic group and the second aromatic group have one or more hydrocarbon groups having 1 to 12 carbon atoms, in which the carbon atoms form bonds only through sp3 hybrid orbitals. Preferred hydrocarbon groups are alkyl groups having 3 to 8 carbon atoms and cycloalkyl groups having 6 to 12 carbon atoms.

[0077] The total number of carbon atoms in the hydrocarbon groups bonded to the first or second aromatic group is 6 or more. Furthermore, the total number of carbon atoms in all the hydrocarbon groups bonded to the first and second aromatic groups is 8 or more, preferably 12 or more. By bonding the hydrocarbon groups with low atomic refraction in this manner, the monoamine compound can be an organic compound with a low refractive index.

[0078] Furthermore, a higher number of π electrons derived from the unsaturated bonds of carbon atoms is advantageous for carrier transport. The total number of carbon atoms in all of the hydrocarbon groups bonded to the first aromatic group and the second aromatic group is preferably 36 or less, and more preferably 30 or less, in order to maintain good carrier transport performance.

[0079] The third aromatic group is a substituted or unsubstituted monocyclic ring, or a substituted or unsubstituted condensed ring having 3 or fewer rings. As the number of rings of the condensed ring increases, the refractive index tends to increase. Further, as the number of rings of the condensed ring increases, absorption and emission of light in the visible region come to be observed. Therefore, by setting the condensed ring to 3 or fewer rings, it is possible to obtain a material that maintains a low refractive index and is less affected by absorption and emission. Incidentally, in order to maintain a low refractive index, the number of carbons forming the ring of the third aromatic group is preferably 6 or more and 13 or less. Specific examples of the third aromatic group include a benzene ring, a naphthalene ring, a fluorene ring, and an acenaphthylene ring. In particular, since the hole transport property is good, the third aromatic group preferably contains a fluorene ring, and more preferably is a fluorene ring.

[0080] For example, as the first organic compound, an organic compound represented by general formula (G1) to general formula (G4) can be used. The organic compounds represented by general formula (G1) to general formula (G4) can be said to be an example of a monoamine compound and an example of a triarylamine compound.

[0081]

Chemical formula

[0082] In general formula (G1), Ar 1 and Ar 2 each independently represent a substituted or unsubstituted benzene ring, or a substituent in which two or three substituted or unsubstituted benzene rings are bonded to each other. However, one or both of Ar 1 and Ar 2 have one or more hydrocarbon groups having 1 to 12 carbon atoms in which carbon forms bonds only with sp3 hybrid orbitals, and the total number of carbons contained in all the hydrocarbon groups bonded to Ar 1 and Ar 2 is 8 or more, and the total number of carbons contained in all the hydrocarbon groups bonded to either one of Ar 1 and Ar 2 is 6 or more. R1 ~R 3 Each of these independently represents an alkyl group with 1 to 4 carbon atoms, and u represents an integer between 0 and 4. 1 and R 2 They may be joined to each other to form a ring.

[0083] Ar 1 and Ar 2 Specifically, examples include substituted or unsubstituted phenyl groups, biphenyl groups, terphenyl groups, and naphthylphenyl groups.

[0084] As hydrocarbon groups having 1 to 12 carbon atoms in which carbon atoms form bonds only through sp3 hybrid orbitals, alkyl groups having 3 to 8 carbon atoms and cycloalkyl groups having 6 to 12 carbon atoms are preferred. Specifically, examples include propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, neohexyl group, heptyl group, octyl group, cyclohexyl group, 4-methylcyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, decahydronaphthyl group, cycloundecyl group, and cyclododecyl group. In particular, tert-butyl group, cyclohexyl group, and cyclododecyl group are preferred.

[0085] Note that Ar 1 or Ar 2 If multiple linear alkyl groups having 1 or 2 carbon atoms are bonded to the hydrocarbon group, these linear alkyl groups may bond to each other to form a ring.

[0086] [ka]

[0087] In the general formula (G2), n, m, p, and r each independently represent 1 or 2, and s, t, and u each independently represent an integer between 0 and 4 (inclusive). Also, n+p and m+r are each independently 2 or 3. 1 ~R 3 Each of these independently represents an alkyl group having 1 to 4 carbon atoms, and R 4 and R 5 Each of these independently represents hydrogen or a hydrocarbon group having 1 to 3 carbon atoms, and R 10 ~R 14 and R 20 ~R 24 Each of these independently represents a hydrocarbon group with 1 to 12 carbon atoms, in which hydrogen or carbon atoms form bonds solely through sp3 hybrid orbitals. 10 ~R 14 and R 20 ~R 24 The total amount of carbon contained in is 8 or more, and R 10 ~R 14 or R 20 ~R 24 The total number of carbon atoms in either one of them is 6 or more. 1 and R 2 They may be bonded to each other to form a ring, R 4 , R 5 , R 10 ~R 14 , and R 20 ~R 24 The adjacent groups may be bonded to each other to form a ring.

[0088] [ka]

[0089] In the general formula (G3), n and p independently represent 1 or 2, and s and u independently represent an integer between 0 and 4 (inclusive). Also, n+p is either 2 or 3. 1 ~R 3 Each of these independently represents an alkyl group having 1 to 4 carbon atoms, and R 4 R represents hydrogen or a hydrocarbon group having 1 to 3 carbon atoms.10 ~R 14 and R 20 ~R 24 Each of these independently represents a hydrocarbon group with 1 to 12 carbon atoms, in which hydrogen or carbon atoms form bonds solely through sp3 hybrid orbitals. 10 ~R 14 and R 20 ~R 24 The total amount of carbon contained in is 8 or more, and R 10 ~R 14 or R 20 ~R 24 The total amount of carbon in either one of them is 6 or more. Also, R 1 and R 2 They may be bonded to each other to form a ring, R 4 , R 10 ~R 14 , and R 20 ~R 24 The adjacent groups may be bonded to each other to form a ring.

[0090] In general formulas (G2) and (G3), examples of hydrocarbon groups having 1 to 3 carbon atoms include methyl, ethyl, and propyl groups. In addition to the above, examples of hydrocarbon groups having 1 to 4 carbon atoms include butyl groups.

[0091] In general formulas (G2) and (G3), when n is 2, the types of substituents, the number of substituents, and the positions of the bonds on the two phenylene groups may be the same or different. Similarly, when any of m, p, or r is 2, the types of substituents, the number of substituents, and the positions of the bonds on the two phenylene groups may be the same or different.

[0092] Furthermore, it is preferable that s, t, and u are each independently 0. Also, if s is an integer between 2 and 4, multiple R 4 These may be the same or different, and if t is an integer between 2 and 4, then multiple R 5may be the same or different from each other. When u is an integer of 2 or more and 4 or less, a plurality of R 3 may be the same or different from each other.

[0093]

Chemical formula

[0094] In the general formula (G4), u represents an integer of 0 or more and 4 or less, and R 1 to R 3 each independently represents an alkyl group having 1 or more and 4 or less carbon atoms, and R 10 to R 14 and R 20 to R 24 each independently represents hydrogen or a hydrocarbon group having 1 or more and 12 or less carbon atoms in which carbon forms bonds only with sp3 hybrid orbitals. Incidentally, R 10 to R 14 and R 20 to R 24 the total number of carbons contained in is 8 or more, and the total number of carbons contained in either one of R 10 to R 14 or R 20 to R 24 is 6 or more. Also, R 1 and R 2 may be bonded to each other to form a ring, and R 10 to R 14 , and, R 20 to R 24 may be such that adjacent groups are bonded to each other to form a ring.

[0095] It is preferable that u is 0. Also, when u is an integer of 2 or more and 4 or less, a plurality of R 3 may be the same or different from each other.

[0096] In general formulas (G2) to (G4), R 10 to R 14 and R 20 to R 24is preferably any one of hydrogen, a tert-butyl group, and a cyclohexyl group, respectively independently, because the refractive index can be lowered. Also, R 10 to R 14 at least three of, and R 20 to R 24 when at least three of them are hydrogen, it is difficult to inhibit carrier transportability, which is preferable.

[0097] Further, as an example of the first organic compound, an arylamine compound having at least one aromatic group, the aromatic group having the first to third benzene rings and at least three alkyl groups can be mentioned. The first to third benzene rings are bonded in this order, and it is assumed that the first benzene ring is directly bonded to the nitrogen atom of the amine.

[0098] The first benzene ring may further have a substituted or unsubstituted phenyl group, and preferably has an unsubstituted phenyl group. Also, the second benzene ring or the third benzene ring may have a phenyl group substituted with an alkyl group.

[0099] Among the first to third benzene rings, the carbon atoms at the 1-position and 3-position of two or more benzene rings, preferably all benzene rings, are not directly bonded to hydrogen, and are bonded to any one of the above-mentioned first to third benzene rings, the phenyl group substituted with the above-mentioned alkyl group, the above-mentioned at least three alkyl groups, and the nitrogen atom of the above-mentioned amine.

[0100] Further, the arylamine compound preferably further has a second aromatic group. The second aromatic group is preferably a group having an unsubstituted monocyclic ring or a substituted or unsubstituted condensed ring of 3 rings or less, and among them, a substituted or unsubstituted condensed ring of 3 rings or less, and the condensed ring is more preferably a group having a condensed ring with 6 to 13 carbon atoms forming the ring, and further preferably a group having a fluorene ring. As the second aromatic group, a dimethylfluorenyl group is preferable.

[0101] Furthermore, it is preferable that the above arylamine compound further has a third aromatic group. The third aromatic group has one to three substituted or unsubstituted benzene rings.

[0102] The at least three alkyl groups mentioned above, and the alkyl groups substituted for the phenyl group, are preferably chain alkyl groups having 2 to 5 carbon atoms, more preferably branched chain alkyl groups having 3 to 5 carbon atoms, and even more preferably t-butyl groups.

[0103] For example, as the first organic compound, an organic compound represented by general formula (G11) to general formula (G13) can be used. The organic compounds represented by general formula (G11) to general formula (G13) can be considered examples of monoamine compounds and examples of triarylmonoamine compounds.

[0104] [ka]

[0105] In general formula (G11), Ar 101 R represents a substituted or unsubstituted benzene ring, or a substituent consisting of two or three substituted or unsubstituted benzene rings bonded to each other. 106 ~R 108 Each of these independently represents an alkyl group with 1 to 4 carbon atoms, v represents an integer between 0 and 4, and R 111 ~R 115 Of these, one represents a substituent represented by general formula (g1), and the others independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted phenyl group. 111 ~R 115 The number of substituted or unsubstituted phenyl groups in is 1 or less. Furthermore, it is preferable that the phenyl group is unsubstituted. If the phenyl group has a substituent, the substituent is an alkyl group having 1 to 6 carbon atoms.

[0106] Ar 101Specifically, examples include substituted or unsubstituted phenyl groups, biphenyl groups, terphenyl groups, and naphthylphenyl groups.

[0107] Note that if v is 2 or more, multiple R 108 These may be the same or different.

[0108] In general formula (g1), R 121 ~R 125 One of these represents a substituent represented by general formula (g2), and the others each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms.

[0109] In general formula (g2), R 131 ~R 135 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms.

[0110] R 111 ~R 115 , R 121 ~R 125 , and R 131 ~R 135 Of these, at least three are alkyl groups having 1 to 6 carbon atoms. This allows the organic compound represented by the above general formula (G11) to be an arylamine compound having a low refractive index.

[0111] R 121 ~R 125 and R 131 ~R 135 In R, there is one or fewer phenyl groups substituted with an alkyl group having 1 to 6 carbon atoms, i.e., R 121 ~R 125 and R 131 ~R 135 In this set, the number of phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms shall be 1 or 0.

[0112] Note, R112 and R 114 , R 122 and R 124 , and R 132 and R 134 In at least two of the three combinations, at least one of R is not hydrogen. That is, R 112 and R 114 A benzene ring having R 122 and R 124 A benzene ring having R 132 and R 134 In a benzene ring having , in two or more benzene rings, at least one of the carbon atoms at the meta position in each is not hydrogen, i.e., it has a substituent. Also, in this case, R 112 , R 114 , R 122 , R 124 At least one of them is not hydrogen, and R 132 and R 134 Preferably, at least one of them is something other than hydrogen.

[0113] Examples of alkyl groups having 1 to 4 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, and isobutyl groups, with tert-butyl being particularly preferred.

[0114] When the benzene ring or phenyl group has substituents, alkyl groups having 1 to 6 carbon atoms and cycloalkyl groups having 5 to 12 carbon atoms can be used as substituents.

[0115] From the viewpoint of lowering the refractive index, a chain-type alkyl group having 2 or more carbon atoms is preferred, and from the viewpoint of ensuring carrier transportability, a chain-type alkyl group having 5 or fewer carbon atoms is preferred. Furthermore, a branched chain-type alkyl group having 3 or more carbon atoms exhibits a significant refractive index reduction effect. In other words, among the above-mentioned alkyl groups having 1 to 6 carbon atoms, a chain-type alkyl group having 2 to 5 carbon atoms is preferred, and a branched chain-type alkyl group having 3 to 5 carbon atoms is even more preferred. Examples of alkyl groups having 1 to 6 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, and hexyl group, with the tert-butyl group being particularly preferred.

[0116] Examples of cycloalkyl groups having 5 to 12 carbon atoms include cyclohexyl group, 4-methylcyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, decahydronaphthyl group, cycloundecyl group, and cyclododecyl group. Cycloalkyl groups having 6 or more carbon atoms are preferred for lowering the refractive index, and cyclohexyl group and cyclododecyl group are particularly preferred.

[0117] General formula (G12) is, in general formula (G11), Ar 101 However, this is an example of a substituent where two or three substituted or unsubstituted benzene rings are bonded to each other. Therefore, explanations of parts that are similar to general formula (G11) may be omitted.

[0118] [ka]

[0119] In general formula (G12), R 106 ~R 109 Each independently represents an alkyl group having 1 to 4 carbon atoms, each independently represents an integer between 0 and 4, each independently represents 1 or 2, and x+y is 2 or 3. Both x and y are preferably 1. 141 ~R145 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 5 to 12 carbon atoms.

[0120] Note that if v is 2 or more, multiple R 108 These may be the same or different. Similarly, if w is 2 or more, there may be multiple R 109 These may be the same or different.

[0121] When x is 2, the types of substituents, the number of substituents, and the positions of the bonds on the two phenylene groups may be the same or different. Similarly, when y is 2, the types of substituents and the number of substituents on the two phenyl groups may be the same or different.

[0122] General formula (G13) is, in general formula (G11), Ar 101 However, this is an example of a single substituted or unsubstituted benzene ring. Therefore, explanations of parts similar to the general formula (G11) may be omitted.

[0123] [ka]

[0124] In general formula (G13), R 101 ~R 105 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 6 to 12 carbon atoms, and a substituted or unsubstituted phenyl group.

[0125] R 101 ~R 105 Of these, R 103 It is preferable that one of the groups is a cyclohexyl group and the rest are all hydrogen. Also, R 101 ~R 105 Of these, R 101 It is preferable that the group is an unsubstituted phenyl group and the rest are all hydrogen atoms, as this improves hole transportability.

[0126] Specifically, organic compounds that can be used as the first organic compound include N,N-bis(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: dchPAF), N-[(3',5'-diter-butyl)-1,1'-biphenyl-4-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBuBichPAF), and N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-N-(4-cyclohexylphenyl) (Rohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF), N-[(3,3',5'-t-butyl)-1,1'-biphenyl-5-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBichPAF), N-(1,1'-biphenyl-2-yl)-N-[(3,3',5'-tri-t-butyl)-1,1'-biphenyl-5-yl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBioFBi), N -(4-tert-butylphenyl)-N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPtBuPAF), N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-02), N-(4-cyclohexylphenyl)-N-(3 ,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-02), N-(1,1'-biphenyl-2-yl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-03), and N-(4-cyclohexylphenyl)-N-(3'',5',5''-tri-t-butyl-1,Examples include 1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-03). The synthesis methods for these organic compounds are described in detail in the reference examples.

[0127] [Second Organic Compound] As described above, the second organic compound contains fluorine. The second organic compound is particularly preferably composed of a cyano group.

[0128] The second organic compound preferably exhibits electron-accepting ability with respect to the first organic compound. To achieve this, the lowest unoccupied orbital (LUMO) level of the second organic compound is preferably -5.0 eV or lower.

[0129] In a composite material according to one aspect of the present invention, the mass percentage concentration of the second organic compound is preferably 10 wt% or less, more preferably 5 wt% or less. Alternatively, in a composite material according to one aspect of the present invention, the volume percentage concentration of the second organic compound is preferably 10 vol% or less, more preferably 5 vol% or less, and even more preferably 3 vol% or less. By lowering the concentration of the second organic compound, the absorption of light in the visible region can be suppressed. This makes it possible to increase the luminous efficiency, for example, in a light-emitting device. Furthermore, when a layer containing the composite material according to one aspect of the present invention is formed in common to multiple light-emitting devices in a light-emitting device, crosstalk can be suppressed.

[0130] Examples of the second organic compound include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. Furthermore, radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups, or cyano groups) [3] are preferred because they have very high electron-accepting properties. Specifically, examples include α,α',α''-1,2,3-cyclopropanetriylidenates[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates[2,3,4,5,6-pentafluorobenzeneacetonitrile].

[0131] As described above, the composite material of this embodiment exhibits strong interaction between the first and second organic compounds, a low refractive index, and high heat resistance. Therefore, it is possible to improve the light extraction efficiency of the light-emitting device. Furthermore, it is possible to obtain an optical device with good current-voltage characteristics. In addition, the reliability of the optical device can be improved.

[0132] This embodiment can be appropriately combined with other embodiments and examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, the configuration examples can be appropriately combined.

[0133] (Embodiment 2) In this embodiment, a light-emitting device according to one aspect of the present invention will be described with reference to Figure 1. In this embodiment, a light-emitting device having the function of emitting visible light or near-infrared light will be described.

[0134] [Example configuration of a light-emitting device] ≪Basic Structure of Light-Emitting Devices≫ Figures 1A to 1D show an example of a light-emitting device having an EL layer between a pair of electrodes.

[0135] The light-emitting device shown in Figure 1A has a structure (single structure) in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102. The EL layer 103 has at least a light-emitting layer. The EL layer 103 may further have one or more layers from among various layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a carrier block layer, an exciton block layer, and a charge generation layer.

[0136] Figure 1B shows an example of the laminated structure of the EL layer 103. In this embodiment, the case in which the first electrode 101 functions as the anode and the second electrode 102 functions as the cathode will be explained as an example. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, an emissive layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially laminated on the first electrode 101. The hole injection layer 111, the hole transport layer 112, the emissive layer 113, the electron transport layer 114, and the electron injection layer 115 may each be a single layer or a laminated structure. When the first electrode 101 is the cathode and the second electrode 102 is the anode, the lamination order is reversed.

[0137] The light-emitting device may have multiple EL layers between a pair of electrodes. For example, it is preferable that the light-emitting device has n EL layers (where n is an integer of 2 or more), and has a charge generation layer 104 between the (n-1)th EL layer and the nth EL layer.

[0138] Figure 1C shows a tandem light-emitting device having two EL layers (EL layers 103a and 103b) between a pair of electrodes. Figure 1D shows a tandem light-emitting device having three EL layers (EL layers 103a, 103b, and 103c).

[0139] Each of the EL layers 103a, 103b, and 103c has at least an emissive layer. Even when there are multiple EL layers, such as in the tandem structure shown in Figures 1C and 1D, a stacked structure similar to that of EL layer 103 shown in Figure 1B can be applied to each EL layer. Each of the EL layers 103a, 103b, and 103c may have one or more layers from among the hole injection layer 111, hole transport layer 112, electron transport layer 114, and electron injection layer 115.

[0140] The charge generation layer 104 shown in Figure 1C has the function of injecting electrons into one of the EL layers 103a and 103b, and holes into the other, when a voltage is applied to the first electrode 101 and the second electrode 102. Therefore, in Figure 1C, when a voltage is applied to the first electrode 101 such that its potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 104 into the EL layer 103a and holes are injected into the EL layer 103b.

[0141] Furthermore, from the viewpoint of light extraction efficiency, it is preferable that the charge generation layer 104 transmits visible light or near-infrared light (specifically, the transmittance of visible light or near-infrared light through the charge generation layer 104 is 40% or more). In addition, the charge generation layer 104 can function even if its conductivity is lower than one or both of the first electrode 101 and the second electrode 102.

[0142] Furthermore, if providing the EL layers in contact with each other forms the same configuration as the charge generation layer 104 between them, the EL layers can be provided in contact with each other without the need for a charge generation layer. For example, if a charge generation region is formed on one side of the EL layer, the EL layer can be provided in contact with that side.

[0143] Tandem-structured light-emitting devices have higher current efficiency compared to single-structured devices, requiring less current to produce the same brightness. Therefore, they have a longer lifespan, improving the reliability of light-emitting devices and electronic equipment.

[0144] The light-emitting layer 113 may have a configuration that appropriately combines a light-emitting material with multiple other materials to obtain fluorescence or phosphorescence emission at a desired wavelength. Alternatively, the light-emitting layer 113 may have a laminated structure with different emission wavelengths. In this case, the light-emitting material and other materials used in each laminated light-emitting layer may be different materials. Furthermore, the EL layers 103a, 103b, and 103c shown in Figures 1C and 1D may be configured to emit light of different wavelengths. In this case as well, the light-emitting material and other materials used in each light-emitting layer may be different materials. For example, in Figure 1C, by configuring EL layer 103a to emit red and green light, and EL layer 103b to emit blue light, it is possible to obtain a light-emitting device that emits white light as a whole. Also, a single light-emitting device may have multiple light-emitting layers or EL layers of the same color. For example, in Figure 1D, by configuring the EL layer 103a to emit a first blue light, the EL layer 103b to emit yellow, yellow-green, or green and red light, and the EL layer 103c to emit a second blue light, it becomes possible to obtain a light-emitting device that emits white light as a whole.

[0145] In one embodiment of the present invention, the light emission obtained from the EL layer may be enhanced by causing resonance between a pair of electrodes. For example, in Figure 1B, by making the first electrode 101 a reflective electrode and the second electrode 102 a semi-transparent / semi-reflective electrode, a micro-optical resonator (microcavity) structure can be formed, thereby enhancing the light emission obtained from the EL layer 103.

[0146] By applying a microcavity structure to the light-emitting device, it is possible to extract light of different wavelengths (monochromatic light) even if the same EL layer is present. Therefore, it becomes unnecessary to form different functional layers for each pixel (so-called color separation) in order to obtain different emission colors. Consequently, it is easy to achieve high resolution. It is also possible to combine it with a colored layer (color filter). Furthermore, it is possible to strengthen the emission intensity in the front direction at a specific wavelength, thereby reducing power consumption.

[0147] Furthermore, if the first electrode 101 of the light-emitting device is a reflective electrode consisting of a laminated structure of a conductive film that reflects visible light or near-infrared light and a conductive film that is transparent to visible light or near-infrared light, optical adjustment can be performed by controlling the thickness of the transparent conductive film. Specifically, it is preferable to adjust the inter-electrode distance between the first electrode 101 and the second electrode 102 to be approximately mλ / 2 (where m is a natural number) with respect to the wavelength λ of the light obtained from the light-emitting layer 113.

[0148] Furthermore, in order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region of the light-emitting layer 113 where the desired light is obtained (light-emitting region), and the optical distance from the second electrode 102 to the region of the light-emitting layer 113 where the desired light is obtained (light-emitting region), so that they are both approximately (2m'+1)λ / 4 (where m' is a natural number). Here, the light-emitting region refers to the region in the light-emitting layer 113 where holes and electrons recombine.

[0149] By performing such optical adjustments, the spectrum of light obtained from the light-emitting layer 113 can be narrowed, resulting in light emission with good color purity.

[0150] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can be precisely defined as the total thickness from the reflective region of the first electrode 101 to the reflective region of the second electrode 102. However, since it is difficult to precisely determine the reflective regions of the first electrode 101 and the second electrode 102, the above effects can be sufficiently obtained by assuming that any position on the first electrode 101 and the second electrode 102 are reflective regions. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be precisely defined as the optical distance between the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which the desired light is obtained. However, since it is difficult to precisely determine the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which the desired light is obtained, the above effects can be sufficiently obtained by assuming that any position on the first electrode 101 is a reflective region and any position on the light-emitting layer from which the desired light is obtained is a light-emitting region.

[0151] At least one of the first electrode 101 and the second electrode 102 is an electrode that is transparent to visible light or near-infrared light. The transmittance of visible light or near-infrared light of the electrode that is transparent to visible light or near-infrared light shall be 40% or more. If the electrode that is transparent to visible light or near-infrared light is the above-mentioned semi-transparent / semi-reflective electrode, the reflectance of visible light or near-infrared light of the electrode shall be 20% or more and 80% or less, preferably 40% or more and 70% or less. The resistivity of these electrodes shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0152] If the first electrode 101 or the second electrode 102 is an electrode that reflects visible light or near-infrared light (reflecting electrode), the reflectance of the reflecting electrode for visible light or near-infrared light shall be 40% or more and 100% or less, preferably 70% or more and 100% or less. Furthermore, the resistivity of this electrode shall be 1 × 10⁻⁶ -2 A value of Ωcm or less is preferable.

[0153] ≪Specific structure of a light-emitting device≫ Next, we will describe the specific structure of the light-emitting device. Here, we will use a light-emitting device with a single structure as shown in Figure 1B for our explanation.

[0154] <Electrode> As materials for forming the first electrode 101 and the second electrode 102, any combination of the following materials can be used as long as they satisfy the functions of both electrodes described above. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, these include In-Sn oxide (also known as ITO), In-Si-Sn oxide (also known as ITSO), In-Zn oxide, and In-W-Zn oxide. In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), as well as alloys containing these in appropriate combinations (such as an alloy of silver, palladium, and copper (Ag-Pd-Cu(APC))), can also be used. In addition, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (for example, lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these in appropriate combinations, graphene, etc., can be used.

[0155] When fabricating a light-emitting device having a microcavity structure, the first electrode 101 is formed as a reflective electrode, and the second electrode 102 is formed as a semi-transparent / semi-reflective electrode. Therefore, one or more desired conductive materials can be used and formed in a single layer or in a stacked configuration. The second electrode 102 is formed after the EL layer 103 is formed, by selecting a material in the same manner as described above. Sputtering or vacuum deposition can be used to fabricate these electrodes.

[0156] <Hole injection layer> The hole injection layer 111 is a layer that injects holes from the first electrode 101, which is the anode, into the EL layer 103, and is a layer containing a material with high hole injection properties.

[0157] As a material with high hole injection capabilities, a composite material containing a hole transport material and an acceptor material (electron-accepting material) can be used. In this case, electrons are extracted from the hole transport material by the acceptor material, generating holes in the hole injection layer 111, and these holes are injected into the light-emitting layer 113 via the hole transport layer 112. The hole injection layer 111 may be formed as a single layer of the composite material containing the hole transport material and the acceptor material, or it may be formed by laminating the hole transport material and the acceptor material in separate layers.

[0158] It is preferable to use a composite material according to one embodiment of the present invention, as described in Embodiment 1, for the hole injection layer 111.

[0159] Other materials with high hole injection potential include transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide, as well as phthalocyanine compounds such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (abbreviated as CuPc).

[0160] Furthermore, materials with high hole injection potential include 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviated as TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviated as MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), and 1,3,5-tris[ Aromatic amine compounds such as N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0161] Materials with high hole injection potential include poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD). Alternatively, polymer compounds with added acids such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviated as PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS) can also be used.

[0162] Alternatively, the hole transport material used in the hole injection layer 111 may have at least one of the following skeletons: a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. The hole transport material may be an aromatic amine having substituents including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen atom of the amine via an arylene group.

[0163] Examples of hole-transporting materials 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), and N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d] Ran-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4-(2;1'-binaphthyl-6-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4' '-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4-(6;2'-binaphthyl-2-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBA(βN2)B), 4-(2;2'-binaphthyl-7-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBA(βN2)B-03), 4-(1;2'-binaphthyl-4-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNαNB), 4-(1;2'-binaphthyl-5-yl)-4',4''-Diphenyltriphenylamine (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''-phenyltriphenylamine ( Abbreviations: TPBiAβNBi), 4-(1-naphthyl)-4'-phenyltriphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris(1,1'-biphenyl-4- Il)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-biphenyl]- 4-yl)-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl- Examples include 4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), and N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF).

[0164] Acceptor materials that can be used in the hole injection layer 111 include chloranil and 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN).

[0165] Furthermore, as acceptor materials, oxides of metals belonging to groups 4 through 8 of the periodic table can also be used. Specifically, these include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferred because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. Organic acceptors such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives can also be used.

[0166] <Hole transport layer> The hole transport layer 112 is a layer that transports holes injected from the first electrode 101 by the hole injection layer 111 to the light-emitting layer 113, and is a layer containing a hole-transporting material.

[0167] The hole transport material used in the hole transport layer 112 preferably has the same or close HOMO level as the HOMO level of the hole injection layer 111.

[0168] As for the hole transport material used in the hole transport layer 112, 10 -6 cm 2 A material having a hole mobility of / Vs or higher is preferred. However, other materials can also be used as long as they have higher hole transport capabilities than electron transport.

[0169] When the hole transport layer 112 has a laminated structure, it is preferable that the layer on the light-emitting layer 113 side functions as an electron blocking layer.

[0170] It is preferable to use a first organic compound (hole-transporting material) that can be used in a composite material according to one embodiment of the present invention, as described in Embodiment 1, for the hole transport layer 112.

[0171] Furthermore, by using the first organic compound in both the hole injection layer 111 and the hole transport layer 112, the thickness of the low refractive index layer in the light-emitting device can be increased (the proportion occupied by the low refractive index layer can be increased), thereby improving the light extraction efficiency.

[0172] By using the same first organic compound in both the hole injection layer 111 and the hole transport layer 112, the refractive index step can be reduced and the light extraction efficiency can be improved.

[0173] Furthermore, the hole transport layer 112 can be made of a hole transport material that can be used in the hole injection layer 111.

[0174] In addition, preferred hole transport materials for the hole transport layer 112 include π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, thiophene derivatives, furan derivatives) and aromatic amines (compounds having an aromatic amine skeleton) that have high hole transport properties.

[0175] Examples of carbazole derivatives (compounds having a carbazole skeleton) include bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives) and aromatic amines having a carbazolyl group.

[0176] Examples of bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives) include 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 9,9'-bis(1,1'-biphenyl-4-yl)-3,3'-bi-9H-carbazole, 9,9'-bis(1,1'-biphenyl-3-yl)-3,3'-bi-9H-carbazole, 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviated as mBPCCBP), and 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP).

[0177] Aromatic amines containing a carbazolyl group include, specifically, N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviation: PCBiF), 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl)amine (abbreviation: PCA1BP), and N,N'-bis(9-phenylcarbazole-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), PCzPCA1, PCzPCA2, PCzPCN1, 3-[N-(4-diphenylaminophenyl)-N-phenyl [Nylamino]-9-phenylcarbazole (abbreviated as PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviated as PCzTPN2), 2-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]spiro-9,9' Examples include bifluorene (abbreviated as PCASF), N-[4-(9H-carbazole-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviated as YGA1BP), N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviated as YGA2F), and 4,4',4''-tris(carbazole-9-yl)triphenylamine (abbreviated as TCTA).

[0178] In addition to the above, other examples of carbazole derivatives include 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as CzPA).

[0179] Examples of thiophene derivatives (compounds having a thiophene skeleton) and furan derivatives (compounds having a furan skeleton) include, specifically, compounds having a thiophene skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II).

[0180] Aromatic amines include, specifically, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), and 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl )amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N- Examples include phenylamino]spiro-9,9'-bifluorene (abbreviated as DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviated as 1'-TNATA), TDATA, m-MTDATA, N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), DPAB, DNTPD, and DPA3B.

[0181] Polymer compounds such as PVK, PVTPA, PTPDMA, and Poly-TPD can also be used as hole-transporting materials.

[0182] The hole transport material is not limited to the above, and can be one or more of various known materials used in combination for the hole injection layer 111 and the hole transport layer 112.

[0183] In a light-emitting device according to one aspect of the present invention, it is preferable that the HOMO level of the hole transport material used in the hole transport layer 112 is less than or equal to the HOMO level of the hole transport material used in the hole injection layer 111. It is preferable that the difference between the HOMO level of the hole transport material used in the hole transport layer 112 and the HOMO level of the hole transport material used in the hole injection layer 111 is within 0.2 eV. It is even preferable that the hole transport material used in the hole injection layer 111 and the hole transport material used in the hole transport layer 112 are the same, as this allows for smoother hole injection.

[0184] When the hole transport layer 112 has a laminated structure, it is preferable that the HOMO level of the hole transport material used in the layer formed on the light-emitting layer 113 side is lower (deeper) than the HOMO level of the hole transport material used in the layer formed on the hole injection layer 111 side. Furthermore, it is preferable that the difference between the HOMO levels of the two hole transport materials is within 0.2 eV. By having the above relationship between the HOMO levels of the hole transport materials used in the hole injection layer 111 and the laminated hole transport layer 112, hole injection into each layer can be performed smoothly, preventing an increase in the driving voltage and a state of insufficient holes in the light-emitting layer 113.

[0185] When the hole transport layer 112 has a laminated structure, it is preferable that the hole transport material used in the layer formed on the light-emitting layer 113 side has a hole transport skeleton. As the hole transport skeleton, a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and anthracene skeleton are preferred, as they do not cause the HOMO level of the hole transport material to become too high.

[0186] <Luminous layer> The light-emitting layer 113 is a layer containing a light-emitting substance. The light-emitting layer 113 can have one or more kinds of light-emitting substances. As the light-emitting substance, substances exhibiting light-emitting colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, red, etc. can be appropriately used. Also, as the light-emitting substance, a substance that emits near-infrared light can be used. Further, by using different light-emitting substances in a plurality of light-emitting layers, a configuration that exhibits different light-emitting colors (for example, white light emission obtained by combining light-emitting colors in a complementary color relationship) can be achieved. Additionally, one light-emitting layer may have different light-emitting substances.

[0187] In addition to the light-emitting substance (guest material), the light-emitting layer 113 preferably has one or more kinds of organic compounds (host material, assist material, etc.). As one or more kinds of organic compounds, one or both of the hole-transporting material and the electron-transporting material described in this embodiment can be used. Also, a bipolar material may be used as one or more kinds of organic compounds.

[0188] There is no particular limitation on the light-emitting substance that can be used in the light-emitting layer 113, and a light-emitting substance that converts singlet excitation energy into light emission in the visible light region or the near-infrared light region, or a light-emitting substance that converts triplet excitation energy into light emission in the visible light region or the near-infrared light region can be used.

[0189] Examples of luminescent materials that convert singlet excitation energy into light include fluorescent materials, such as pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. Pyrene derivatives are particularly preferred because they have a high luminescence quantum yield. Specific examples of pyrene derivatives include 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'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), and N,N'-bis(dibenzothiophen-2-yl)-N,N' Examples include -diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), and N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03).

[0190] Other examples include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), and 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl) Lubazole-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 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-antryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl [2-Anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (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. can be used.

[0191] In addition, examples of the luminescent material that converts triplet excitation energy into luminescence include substances that emit phosphorescence (phosphorescent materials), and thermally activated delayed fluorescence (Thermally Activated Delayed Fluorescence: TADF) materials that exhibit thermally activated delayed fluorescence, and the like.

[0192] Examples of phosphorescent materials include organometallic complexes, metal complexes (platinum complexes), and rare earth metal complexes. Since these exhibit different emission colors (emission peaks) for each substance, they are appropriately selected and used as needed.

[0193] Examples of phosphorescent materials that exhibit blue or green and have a peak wavelength of the emission spectrum in the range of 450 nm or more and 570 nm or less include the following substances.

[0194] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN 2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [ Ir(iPr5btz)3]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: Ir(iPr5btz)3]), organometallic complexes having a 4H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato] Organometallic complexes having a 1H-triazole skeleton, such as 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]), organometallic complexes having an imidazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenantridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’Examples include organometallic complexes that use phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as Fir(acac)).

[0195] Examples of phosphorescent materials that exhibit a green or yellow color and have a peak wavelength of emission spectrum between 495 nm and 590 nm include the following substances:

[0196] For example, 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: [I r(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN 3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), organometallic iridium complexes having a pyrimidine skeleton such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), tris(2-phenylpyridinato-N,C 2’ Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinate-N,C) 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinate)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinate)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinate-N,C) 2’ Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C) 2’ iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), organometallic iridium complexes having a pyridine skeleton such as bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC], and bis(2,4-diphenyl-1,3-oxazolato-N,C 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinate-N,C 2’Iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolat-N,C) 2’ Examples include organometallic complexes such as iridium(III) acetylacetonate (abbreviated as [Ir(bt)2(acac)]), as well as rare earth metal complexes such as tris(acetylacetonate)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]).

[0197] Examples of phosphorescent materials that exhibit a yellow or red color and have a peak wavelength of emission spectrum between 570 nm and 750 nm include the following substances:

[0198] For example, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), tris(4-t-butyl-6-phenylpyrimidinato)iridium ( Organometallic complexes having a pyrimidine skeleton such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyradinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ 2O,O') Iridium(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyradinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O') Iridium(III) (abbreviation: [Ir(dmdppr-dmCP)2(dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C 2’ Iridium(III) (abbreviation: [Ir(mpq)2(acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(dpq)2(acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), bis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyradinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 Organometallic complexes with a pyrazine skeleton, such as O,O') Iridium(III) (abbreviation: [Ir(dmdppr-m5CP)2(dpm)]), and tris(1-phenylisoquinolinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C) 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ 2Examples include organometallic complexes with a pyridine skeleton such as O,O')iridium(III), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as [PtOEP]), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]).

[0199] As for the organic compounds (host material, assist material, etc.) used in the light-emitting layer 113, one or more materials having an energy gap larger than the energy gap of the light-emitting material can be selected and used.

[0200] When the light-emitting material used in the light-emitting layer 113 is a fluorescent material, it is preferable to use an organic compound that has a large singlet excited state energy level and a small triplet excited state energy level as the organic compound used in combination with the light-emitting material.

[0201] Although some of these examples overlap with those above, the following are specific examples of organic compounds that are preferred combinations with luminescent materials (fluorescent or phosphorescent materials).

[0202] When the luminescent material is a fluorescent material, organic compounds that can be used in combination with the luminescent material include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0203] Specific examples of organic compounds (host materials) used in combination with fluorescent materials include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as DPCzPA), PCPN, 9,10-diphenylanthracene (abbreviated as DPAnth), and N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated as CzA1PA). ), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviation: PCAPBA), N-(9,10-di Phenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), CzPA, 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl [Lu]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-biantryl (abbreviation: BANT), 9,9'-(stilbene-3,Examples include 3'-diyl)diphenanthrene (abbreviated as DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviated as DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviated as TPB3), 5,12-diphenyltetracene, and 5,12-bis(biphenyl-2-yl)tetracene.

[0204] When the luminescent material is a phosphorescent material, an organic compound with a triplet excitation energy greater than the triplet excitation energy (energy difference between the ground state and the triplet excited state) of the luminescent material can be selected as the organic compound to be used in combination with the luminescent material.

[0205] When using multiple organic compounds (for example, a first host material and a second host material (or assist material), etc.) in combination with a light-emitting substance to form an excited complex, it is preferable to use these multiple organic compounds mixed with a phosphorescent material (especially an organometallic complex).

[0206] This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excited complex to the light-emitting material. The combination of organic compounds should preferably be one that readily forms an excited complex, and a combination of a hole-accepting compound (hole transport material) and an electron-accepting compound (electron transport material) is particularly preferable. Specific examples of hole transport materials and electron transport materials can be found in this embodiment. This configuration simultaneously achieves high efficiency, low voltage operation, and a long lifespan for the light-emitting device.

[0207] Organic compounds that can be used in combination with a luminescent material when the luminescent material is a phosphorescent material include aromatic amines, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, zinc-based metal complexes, aluminum-based metal complexes, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, and phenanthroline derivatives.

[0208] Of the above, specific examples of organic compounds with high hole transport properties, such as aromatic amines (compounds having an aromatic amine skeleton), carbazole derivatives, dibenzothiophene derivatives (thiophene derivatives), and dibenzofuran derivatives (furan derivatives), are the same as the specific examples of hole transport materials shown above.

[0209] Specific examples of zinc-based and aluminum-based metal complexes, which are organic compounds with high electron transport properties, include tris(8-quinolinolato)aluminum(III) (abbreviated as Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviated as Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), and bis(8-quinolinolato)zinc(II) (abbreviated as Znq), which are metal complexes having a quinoline skeleton or a benzoquinoline skeleton.

[0210] In addition, metal complexes having oxazole-based or thiazole ligands, such as bis[2-(2-benzoxazolyl)phenolate]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenolate]zinc(II) (abbreviated as ZnBTZ), can also be used.

[0211] Specific examples of organic compounds with high electron transport capabilities, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, and phenanthroline derivatives, include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), and 9-[4-(5-phenyl-1,3,4-oxadiazole] Zole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophone) [f,h](dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs), vasophenanthroline (abbreviation: BPhen), vasocuproin (abbreviation: BCP), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDB) q-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,Examples include quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzof[h]quinoxaline (abbreviation: 6mDBTPDBq-II).

[0212] Specific examples of heterocyclic compounds having a diazine skeleton, a heterocyclic compound having a triazine skeleton, and a heterocyclic compound having a pyridine skeleton, which are organic compounds with high electron transporting properties, include 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 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-fluorene-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluorene)-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), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB).

[0213] Highly electron-transporting organic compounds can also be used, such as polymer compounds like poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy).

[0214] TADF materials are materials that can be upconverted from a triplet excited state to a singlet excited state (reverse intersystem crossing) with a small amount of thermal energy, and that efficiently exhibit emission (fluorescence) from the singlet excited state. Furthermore, conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited state and the singlet excited state of 0 eV to 0.2 eV, preferably 0 eV to 0.1 eV. In addition, delayed fluorescence in TADF materials refers to emission that has a spectrum similar to normal fluorescence but with a remarkably long lifetime. Its lifetime is 10 -6 10 seconds or more, preferably 10 -3 It is more than a second.

[0215] Examples of TADF materials include fullerenes and their derivatives, acridine derivatives such as proflavin, and eosin. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) are also included. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (abbreviated as SnF2(Proto IX)), mesoporphyrin-tin fluoride complexes (abbreviated as SnF2(Meso IX)), hematoporphyrin-tin fluoride complexes (abbreviated as SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complexes (abbreviated as SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complexes (abbreviated as SnF2(OEP)), etioporphyrin-tin fluoride complexes (abbreviated as SnF2(Etio I)), and octaethylporphyrin-platinum chloride complexes (abbreviated as PtCl2OEP).

[0216] Other examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), PCCzPTzn, 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: Heterocyclic compounds having π-electron-rich heteroaromatic rings and π-electron-deficient heteroaromatic rings can be used, such as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). In particular, substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are preferred because both the donor properties of the π-electron-rich heteroaromatic ring and the acceptor properties of the π-electron-deficient heteroaromatic ring become stronger, and the energy difference between the singlet excited state and the triplet excited state becomes smaller.

[0217] Furthermore, when using TADF materials, they can be used in combination with other organic compounds. In particular, they can be combined with the host materials, hole transport materials, and electron transport materials mentioned above.

[0218] Furthermore, the above materials can be used to form the light-emitting layer 113 by combining them with either or both low-molecular-weight materials and high-molecular-weight materials. Known methods (such as vapor deposition, coating, or printing) can also be used for film formation.

[0219] <Electron transport layer> The electron transport layer 114 is a layer that transports electrons injected from the second electrode 102 by the electron injection layer 115 to the light-emitting layer 113. The electron transport layer 114 is a layer containing an electron-transporting material. The electron-transporting material used in the electron transport layer 114 has a density of 1 × 10⁻¹⁶. -6 cm 2 A material having an electron mobility of / Vs or higher is preferred. However, other materials can also be used as long as they have higher electron transport capabilities than holes.

[0220] As electron-transporting materials, in addition to metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, etc., materials with high electron-transporting properties such as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds containing nitrogen-containing heteroaromatic compounds can be used.

[0221] The materials described above can be used as specific examples of electron-transporting materials.

[0222] Furthermore, in a light-emitting device according to one aspect of the present invention, the electron transport layer 114 preferably comprises an electron-transporting material and an organometallic complex of an alkali metal or alkaline earth metal.

[0223] In this case, the electron-transporting material preferably has an anthracene skeleton, and more preferably has both an anthracene skeleton and a heterocyclic skeleton. A nitrogen-containing five-membered ring skeleton is preferred as the heterocyclic skeleton. A nitrogen-containing five-membered ring skeleton that includes two heteroatoms in the ring, such as a pyrazole ring, imidazole ring, oxazole ring, or thiazole ring, is particularly preferred.

[0224] As the organometallic complex of an alkali metal or alkaline earth metal, an organometallic complex of lithium is preferred, and in particular, 8-quinolinolatolithium (abbreviated as Liq) is preferred.

[0225] By reducing the electron transportability in the electron transport layer 114, the amount of electrons injected into the light-emitting layer 113 can be controlled, preventing the light-emitting layer 113 from becoming electron-excessive. Furthermore, by expanding the light-emitting region of the light-emitting layer 113 and distributing the load on the materials constituting the light-emitting layer 113, it is possible to provide a light-emitting device with a long lifespan and high luminous efficiency.

[0226] Furthermore, it is preferable that the electron transport layer 114 has portions in its thickness direction where the mixing ratio of the electron transport material and the organometallic complex of an alkali metal or alkaline earth metal differs. The electron transport layer 114 may also have a concentration gradient, and may be a laminated structure of multiple layers in which the mixing ratios of the electron transport material and the organometallic complex of an alkali metal or alkaline earth metal differ from each other.

[0227] The relative magnitudes of the mixing ratios can be inferred from the detected amounts of atoms or molecules obtained by time-of-flight secondary ion mass spectrometry (ToF-SIMS). In a sample composed of the same two materials but with different mixing ratios, the relative magnitudes of the values ​​detected by ToF-SIMS analysis correspond to the relative abundances of the atoms or molecules of interest. Therefore, by comparing the detected amounts of electron-transporting materials and organometallic complexes, the relative magnitudes of the mixing ratios can be estimated.

[0228] It is preferable that the content of the organometallic complex in the electron transport layer 114 is lower on the second electrode 102 side than on the first electrode 101 side. In other words, it is preferable that the electron transport layer 114 is formed such that the concentration of the organometallic complex increases from the second electrode 102 side towards the first electrode 101 side. That is, in the electron transport layer 114, there is a region on the light-emitting layer 113 side where the amount of electron transporting material is lower than the region where the amount of electron transporting material is higher, or to put it another way, in the electron transport layer 114, there is a region on the light-emitting layer 113 side where the amount of organometallic complex is higher than the region where the amount of organometallic complex is lower.

[0229] In one embodiment of the present invention, a change in carrier balance in the light-emitting device is thought to be caused by a change in the electron mobility of the electron transport layer 114. In one embodiment of the present invention, a concentration difference of an organometallic complex of an alkali metal or alkaline earth metal exists within the electron transport layer 114. The electron transport layer 114 has a region with a high concentration of the organometallic complex between the region with a low concentration of the organometallic complex and the light-emitting layer 113. That is, the region with a low concentration of the organometallic complex is located closer to the second electrode 102 than the region with a high concentration. As the electron mobility of the electron transport layer 114 increases with a higher concentration of the organometallic complex, the electron mobility of the electron transport layer 114 is limited by the region with a low concentration.

[0230] When a voltage is applied to drive the light-emitting device, an organometallic complex of an alkali metal or alkaline earth metal diffuses from the first electrode 101 side to the second electrode 102 side (from a region of high concentration to a region of low concentration) due to the voltage. Because the region of high concentration of the organometallic complex is located on the first electrode 101 side rather than the region of low concentration, the electron mobility of the electron transport layer 114 is improved as the device is driven. This causes a change in the carrier balance inside the light-emitting device, the recombination region moves, and a light-emitting device with a long lifetime can be obtained.

[0231] A light-emitting device according to one embodiment of the present invention having the above configuration has a very long lifespan. In particular, it is possible to significantly extend the lifespan in the region where degradation is extremely small, up to about LT95 (the time it takes for the brightness to decrease to 95% of the initial brightness).

[0232] <Electron injection layer> The electron injection layer 115 is a layer containing materials with high electron injection potential. The electron injection layer 115 contains Liq, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), and lithium oxide (LiO2). x Alkali metals, alkaline earth metals, or compounds thereof can be used. Rare earth metal compounds such as erbium fluoride (ErF3) can also be used. An electride may also be used in the electron injection layer 115. Examples of electrides include a substance obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. The materials that constitute the electron transport layer 114 described above can also be used.

[0233] Furthermore, a composite material containing an electron-transporting material and a donor material (electron-donating material) may be used in the electron injection layer 115. Such a composite material exhibits excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons. Specifically, for example, the electron-transporting material (metal complex, heteroaromatic compound, etc.) used in the electron transport layer 114 described above can be used. As the electron donor, a substance that exhibits electron-donating properties to the organic compound can be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides and alkaline earth metal oxides are also preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Organic compounds such as tetrathiafulvalene (abbreviated as TTF) can also be used.

[0234] <Charge generation layer> In the light-emitting device shown in Figure 1C, the charge generation layer 104 has the function of injecting electrons into the EL layer 103a and holes into the EL layer 103b when a voltage is applied between the first electrode 101 (anode) and the second electrode 102 (cathode).

[0235] The charge generation layer 104 may have a configuration that includes a hole transport material and an acceptor material (electron-accepting material), or a configuration that includes an electron transport material and a donor material. By forming a charge generation layer 104 with such a configuration, it is possible to suppress the increase in driving voltage when the EL layer is stacked.

[0236] It is preferable to use a composite material according to one embodiment of the present invention, as described in Embodiment 1, for the charge generation layer 104.

[0237] In addition, the materials described above can also be used as hole transporting materials, acceptor materials, electron transporting materials, and donor materials, respectively.

[0238] In this embodiment, the light-emitting device can be fabricated using either or both of the following methods: vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing. When using vapor deposition, physical vapor deposition methods (PVD) such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, as well as chemical vapor deposition (CVD), can be used. In particular, the functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) and charge generation layer included in the EL layer can be formed by methods such as vapor deposition (vacuum deposition, etc.), coating (dip coating, die coating, bar coating, spin coating, spray coating, etc.), and printing (inkjet, screen printing, offset printing, flexographic printing, gravure printing, microcontact printing, etc.).

[0239] The materials for the functional layer and charge generation layer constituting the EL layer 103 are not limited to the materials described above. For example, polymer compounds (oligomers, dendrimers, polymers, etc.), medium-molecular-weight compounds (compounds in the intermediate region between low-molecular-weight and high-molecular-weight compounds: molecular weight 400 to 4000), inorganic compounds (quantum dot materials, etc.) may be used as the material for the functional layer. As for the quantum dot material, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, core-type quantum dot materials, etc., can be used.

[0240] This embodiment can be combined with other embodiments as appropriate.

[0241] (Embodiment 3) In this embodiment, a light-emitting device according to one aspect of the present invention will be described with reference to Figures 2 to 5.

[0242] [Example of Light-Emitting Device Configuration 1] Figure 2A shows a top view of the light-emitting device, and Figures 2B and 2C show cross-sectional views between the dashed lines X1-Y1 and X2-Y2 in Figure 2A. The light-emitting devices shown in Figures 2A to 2C can be used, for example, in lighting devices. The light-emitting device may be bottom emission, top emission, or dual emission.

[0243] The light-emitting device shown in Figure 2B comprises a substrate 490a, a substrate 490b, a conductive layer 406, a conductive layer 416, an insulating layer 405, an organic EL device 450 (a first electrode 401, an EL layer 402, and a second electrode 403), and an adhesive layer 407. The organic EL device 450 can also be called a light-emitting element, an organic EL element, or a light-emitting device. The EL layer 402 preferably has a composite material according to one embodiment of the present invention, as shown in Embodiment 1. For example, it is preferable that at least one of the materials for the hole injection layer, the hole transport layer, and the charge generation layer has the composite material.

[0244] The organic EL device 450 has a first electrode 401 on a substrate 490a, an EL layer 402 on the first electrode 401, and a second electrode 403 on the EL layer 402. The organic EL device 450 is sealed by substrate 490a, an adhesive layer 407, and substrate 490b.

[0245] The ends of the first electrode 401, the conductive layer 406, and the conductive layer 416 are each covered with an insulating layer 405. The conductive layer 406 is electrically connected to the first electrode 401, and the conductive layer 416 is electrically connected to the second electrode 403. The conductive layer 406, covered by the insulating layer 405 via the first electrode 401, functions as auxiliary wiring and is electrically connected to the first electrode 401. Having auxiliary wiring electrically connected to the electrodes of the organic EL device 450 is preferable because it can suppress voltage drops caused by the resistance of the electrodes. The conductive layer 406 may be provided on the first electrode 401. Alternatively, auxiliary wiring electrically connected to the second electrode 403 may be provided on the insulating layer 405 or elsewhere.

[0246] Substrates 490a and 490b can be made of glass, quartz, ceramic, sapphire, organic resin, etc., respectively. Using flexible materials for substrates 490a and 490b can increase the flexibility of the display device.

[0247] The light-emitting surface of the light-emitting device may be fitted with one or more of the following: a light extraction structure to improve light extraction efficiency, an antistatic film to suppress dust adhesion, a water-repellent film to make it difficult for dirt to adhere, a hard coat film to suppress the occurrence of scratches during use, and an impact-absorbing layer.

[0248] Examples of insulating materials that can be used for the insulating layer 405 include resins such as acrylic resin and epoxy resin, as well as inorganic insulating materials such as silicon oxide, silicon oxide nitride, silicon nitride, silicon nitride, and aluminum oxide.

[0249] As the adhesive layer 407, various types of curing adhesives can be used, such as UV-curing adhesives, reaction-curing adhesives, thermosetting adhesives, and anaerobic adhesives. Examples of these adhesives include epoxy resins, acrylic resins, silicone resins, phenolic resins, polyimide resins, imide resins, PVC (polyvinyl chloride) resins, PVB (polyvinyl butyral) resins, and EVA (ethylene vinyl acetate) resins. Materials with low moisture permeability, such as epoxy resins, are particularly preferred. Two-component mixed resins may also be used. Adhesive sheets may also be used.

[0250] The light-emitting device shown in Figure 2C comprises a barrier layer 490c, a conductive layer 406, a conductive layer 416, an insulating layer 405, an organic EL device 450, an adhesive layer 407, a barrier layer 423, and a substrate 490b.

[0251] The barrier layer 490c shown in Figure 2C comprises a substrate 420, an adhesive layer 422, and a highly barrier insulating layer 424.

[0252] In the light-emitting device shown in Figure 2C, the organic EL device 450 is positioned between a highly barrier insulating layer 424 and a barrier layer 423. Therefore, even if a resin film with relatively low water resistance is used for the substrates 420 and 490b, it is possible to suppress the ingress of impurities such as water into the organic EL device, which would reduce its lifespan.

[0253] For substrates 420 and 490b, for example, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamide-imide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. may be used. For substrates 420 and 490b, glass with a thickness sufficient to provide flexibility may also be used.

[0254] As the highly barrier insulating layer 424, it is preferable to use an inorganic insulating film. Examples of inorganic insulating films that can be used include silicon nitride film, silicon oxide nitride film, silicon oxide film, silicon nitride oxide film, aluminum oxide film, and aluminum nitride film. Alternatively, hafnium oxide film, yttrium oxide film, zirconium oxide film, gallium oxide film, tantalum oxide film, magnesium oxide film, lanthanum oxide film, cerium oxide film, and neodymium oxide film may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0255] The barrier layer 423 preferably has at least one inorganic film. For example, the barrier layer 423 can be a single-layer inorganic film or a laminated structure of an inorganic film and an organic film. The inorganic insulating film is preferred as the inorganic film. An example of such a laminated structure is a configuration in which a silicon oxynitride film, a silicon oxide film, an organic film, a silicon oxide film, and a silicon nitride film are formed in sequence. By making the barrier layer a laminated structure of an inorganic film and an organic film, impurities (typically hydrogen, water, etc.) that may enter the organic EL device 450 can be effectively suppressed.

[0256] The highly barrier insulating layer 424 and the organic EL device 450 can be formed directly on a flexible substrate 420. In this case, the adhesive layer 422 is unnecessary. Alternatively, the insulating layer 424 and the organic EL device 450 can be formed on a rigid substrate via a release layer and then transferred to the substrate 420. For example, the insulating layer 424 and the organic EL device 450 may be peeled off the rigid substrate by applying heat, force, laser light, etc., to the release layer, and then transferred to the substrate 420 by bonding them using the adhesive layer 422. As the release layer, for example, a laminated structure of inorganic films including a tungsten film and a silicon oxide film, or an organic resin film such as polyimide can be used. When a rigid substrate is used, the insulating layer 424 can be formed at a higher temperature compared to a resin substrate, so the insulating layer 424 can be made into a dense and extremely barrier insulating film.

[0257] [Example of Light-Emitting Device Configuration 2] Figure 3A shows a cross-sectional view of the light-emitting device. The light-emitting device shown in Figure 3A is an active-matrix type light-emitting device in which a transistor and a light-emitting device are electrically connected.

[0258] The light-emitting device shown in Figure 3A includes a substrate 201, a transistor 210, light-emitting devices 203R, 203G, 203B, color filters 206R, 206G, 206B, and a substrate 205, etc.

[0259] In Figure 3A, a transistor 210 is provided on a substrate 201, an insulating layer 202 is provided on the transistor 210, and light-emitting devices 203R, 203G, and 203B are provided on the insulating layer 202.

[0260] The transistor 210 and the light-emitting devices 203R, 203G, and 203B are sealed in a space 207 surrounded by substrates 201, 205, and an adhesive layer 208. The space 207 can be configured, for example, under a reduced pressure atmosphere, an inert atmosphere, or filled with resin.

[0261] The light-emitting device shown in Figure 3A has a configuration in which each pixel has a red sub-pixel (R), a green sub-pixel (G), and a blue sub-pixel (B).

[0262] A light-emitting device according to one aspect of the present invention has a plurality of pixels arranged in a matrix. Each pixel has one or more subpixels. Each subpixel has one light-emitting device. For example, a pixel can be configured to have three subpixels (three colors: R, G, B, or three colors: yellow (Y), cyan (C), and magenta (M)), or four subpixels (four colors: R, G, B, and white (W), or four colors: R, G, B, and Y).

[0263] Figure 3B shows the detailed configurations of light-emitting devices 203R, 203G, and 203B. Light-emitting devices 203R, 203G, and 203B have a common EL layer 213 and a microcavity structure in which the optical distance between the electrodes of each light-emitting device is adjusted according to the light emission color of each light-emitting device. The EL layer 213 preferably has a composite material according to one embodiment of the present invention, as shown in Embodiment 1. For example, it is preferable that at least one of the materials for the hole injection layer, the hole transport layer, and the charge generation layer has the composite material.

[0264] The first electrode 211 functions as a reflective electrode, and the second electrode 215 functions as a semi-transmissive / semi-reflective electrode.

[0265] Light-emitting device 203R is adjusted so that the optical distance between the first electrode 211 and the second electrode 215 is 220R, thereby increasing the intensity of red light. Similarly, light-emitting device 203G is adjusted so that the optical distance between the first electrode 211 and the second electrode 215 is 220G, thereby increasing the intensity of green light, and light-emitting device 203B is adjusted so that the optical distance between the first electrode 211 and the second electrode 215 is 220B, thereby increasing the intensity of blue light.

[0266] As shown in Figure 3B, optical adjustment can be performed by forming a conductive layer 212R on the first electrode 211 in the light-emitting device 203R, and by forming a conductive layer 212G on the first electrode 211 in the light-emitting device 203G. Furthermore, in the light-emitting device 203B, the optical distance 220B may be adjusted by forming a conductive layer of a different thickness than the conductive layers 212R and 212G on the first electrode 211. As shown in Figure 3A, the ends of the first electrode 211, the conductive layer 212R, and the conductive layer 212G are covered with an insulating layer 204.

[0267] The light-emitting device shown in Figure 3A is a top-emission type light-emitting device in which light emitted from a light-emitting device is emitted through color filters of each color formed on the substrate 205. The color filters can allow a specific wavelength range of visible light to pass through and block a specific wavelength range.

[0268] In the red subpixel (R), light emitted from the light-emitting device 203R is emitted through the red color filter 206R. As shown in Figure 3A, by providing the color filter 206R, which allows only the red wavelength range to pass through, at a position overlapping with the light-emitting device 203R, red light emission can be obtained from the light-emitting device 203R.

[0269] Similarly, in the green subpixel (G), light emitted from the light-emitting device 203G is emitted through the green color filter 206G, and in the blue subpixel (B), light emitted from the light-emitting device 203B is emitted through the blue color filter 206B.

[0270] Furthermore, the substrate 205 may be provided with a black matrix 209 (also known as a black layer). In this case, it is preferable that the edges of the color filters overlap with the black matrix 209. In addition, each color filter and the black matrix 209 may be covered with an overcoat layer that transmits visible light.

[0271] The light-emitting device shown in Figure 3C has a configuration in which each pixel has a red sub-pixel (R), a green sub-pixel (G), a blue sub-pixel (B), and a white sub-pixel (W). In Figure 3C, the light from the light-emitting device 203W of the white sub-pixel (W) is emitted to the outside of the light-emitting device without passing through a color filter.

[0272] The optical distance between the first electrode 211 and the second electrode 215 in the light-emitting device 203W may be the same as or different from that of any of the light-emitting devices 203R, 203G, or 203B.

[0273] For example, if the light emitted from the light-emitting device 203W is white light with a low color temperature, and it is desired to increase the intensity of blue light, it is preferable to make the optical distance at the light-emitting device 203W equal to the optical distance 220B at the light-emitting device 203B, as shown in Figure 3C. This makes it possible to bring the light obtained from the light-emitting device 203W closer to the desired color temperature of white light.

[0274] Figure 3A shows an example in which a common EL layer 213 is used for the light-emitting devices of each subpixel of each color. However, as shown in Figure 4A, different EL layers may be used for the light-emitting devices of each subpixel of each color. The microcavity structure described above can also be applied in the same way to Figure 4A.

[0275] Figure 4A shows an example where the light-emitting device 203R has an EL layer 213R, the light-emitting device 203G has an EL layer 213G, and the light-emitting device 203B has an EL layer 213B. The EL layers 213R, 213G, and 213B may have a common layer. For example, the EL layers 213R, 213G, and 213B may have different light-emitting layer configurations, while other layers are common. In Figure 4A, the light emitted by the light-emitting devices 203R, 203G, and 203B may be extracted via a color filter or without a color filter.

[0276] While Figure 3A shows a top-emission type light-emitting device, as shown in Figure 4B, a light-emitting device with a structure that extracts light from the substrate 201 on which the transistor 210 is formed (bottom-emission type) is also one embodiment of the present invention.

[0277] In a bottom-emission type light-emitting device, it is preferable to provide color filters for each color between the substrate 201 and the light-emitting device. Figure 4B shows an example in which a transistor 210 is formed on the substrate 201, an insulating layer 202a is formed on the transistor 210, color filters 206R, 206G, and 206B are formed on the insulating layer 202a, an insulating layer 202b is formed on the color filters 206R, 206G, and 206B, and light-emitting devices 203R, 203G, and 203B are formed on the insulating layer 202b.

[0278] In the case of a top-emission type light-emitting device, a light-shielding substrate and a light-transmitting substrate can be used as substrate 201, and a light-transmitting substrate can be used as substrate 205.

[0279] In the case of a bottom-emission type light-emitting device, a light-shielding substrate and a light-transmitting substrate can be used as substrate 205, and a light-transmitting substrate can be used as substrate 201.

[0280] [Example of Light-Emitting Device Configuration 3] A light-emitting device according to one aspect of the present invention can be a passive matrix type or an active matrix type. An active matrix type light-emitting device will be explained with reference to Figure 5.

[0281] Figure 5A shows a top view of the light-emitting device. Figure 5B shows a cross-sectional view of the section between A and A' shown by the dashed line in Figure 5A.

[0282] The active matrix type light-emitting device shown in Figures 5A and 5B has a pixel section 302, a circuit section 303, a circuit section 304a, and a circuit section 304b.

[0283] Circuit sections 303, 304a, and 304b can each function as a scan line drive circuit (gate driver) or a signal line drive circuit (source driver). Alternatively, they may be circuits that electrically connect an external gate driver or source driver to the pixel section 302.

[0284] A routing wire 307 is provided on the first substrate 301. The routing wire 307 is electrically connected to an FPC 308, which is an external input terminal. The FPC 308 transmits external signals (e.g., video signals, clock signals, start signals, reset signals, etc.) and potentials to circuit sections 303, 304a, and 304b. A printed wiring board (PWB) may also be attached to the FPC 308. The configuration shown in Figures 5A and 5B can also be described as a light-emitting module having a light-emitting device (or light-emitting apparatus) and an FPC.

[0285] The pixel section 302 has multiple pixels, each having an organic EL device 317, a transistor 311, and a transistor 312. Transistor 312 is electrically connected to the first electrode 313 of the organic EL device 317. Transistor 311 functions as a switching transistor. Transistor 312 functions as a current control transistor. The number of transistors in each pixel is not particularly limited and can be provided as needed.

[0286] The circuit section 303 has multiple transistors, including transistor 309 and transistor 310. The circuit section 303 may be formed as a circuit including unipolar (either N-type or P-type only) transistors, or as a CMOS circuit including N-type and P-type transistors. It may also be configured to have an external drive circuit.

[0287] The structure of the transistor in the light-emitting device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverse staggered transistor, etc., can be used. Furthermore, either a top-gate or bottom-gate transistor structure may be used. Alternatively, gates may be provided above and below the semiconductor layer in which the channel is formed.

[0288] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0289] The semiconductor layer of the transistor preferably contains a metal oxide (also called an oxide semiconductor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single-crystal silicon).

[0290] The semiconductor layer preferably comprises, for example, indium, M (where M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0291] In particular, it is preferable to use an oxide (also written as IGZO) containing indium (In), gallium (Ga), and zinc (Zn) as the semiconductor layer.

[0292] When the semiconductor layer is an In-M-Zn oxide, it is preferable that the sputtering target used to deposit the In-M-Zn oxide has an atomic ratio of In that is equal to or greater than the atomic ratio of M. Examples of such atomic ratios of metal elements in a sputtering target include In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:3, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, In:M:Zn=6:1:6, and In:M:Zn=5:2:5.

[0293] The transistors in circuit sections 303, 304a, and 304b and the transistors in pixel section 302 may have the same structure or different structures. The structures of the multiple transistors in circuit sections 303, 304a, and 304b may all be the same or there may be two or more different structures. Similarly, the structures of the multiple transistors in pixel section 302 may all be the same or there may be two or more different structures.

[0294] The end of the first electrode 313 is covered with an insulating layer 314. The insulating layer 314 can be made of one or both of the following: an organic compound such as a negative-type photosensitive resin or a positive-type photosensitive resin (acrylic resin), and an inorganic compound such as silicon oxide, silicon oxide-nitride, or silicon nitride. Preferably, the upper or lower end of the insulating layer 314 has a curved surface with curvature. This improves the coverage of the film formed on the upper layer of the insulating layer 314.

[0295] An EL layer 315 is provided on the first electrode 313, and a second electrode 316 is provided on the EL layer 315. The EL layer 315 has at least one layer from among a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and a charge generation layer. Preferably, the EL layer 315 has a composite material according to one embodiment of the present invention, as shown in Embodiment 1. For example, it is preferable that at least one of the materials for the hole injection layer, the hole transport layer, and the charge generation layer has the composite material.

[0296] Multiple transistors and multiple organic EL devices 317 are sealed by a first substrate 301, a second substrate 306, and a sealing material 305. The space 318 surrounded by the first substrate 301, the second substrate 306, and the sealing material 305 may be filled with an inert gas (nitrogen, argon, etc.) or an organic material (including the sealing material 305).

[0297] The sealing material 305 can be epoxy resin or glass frit. It is preferable to use a material that does not permeate moisture and oxygen as much as possible for the sealing material 305. When using glass frit as the sealing material, it is preferable that the first substrate 301 and the second substrate 306 are glass substrates from the viewpoint of adhesion.

[0298] Figures 5C and 5D show examples of transistors that can be used in light-emitting devices.

[0299] The transistor 320 shown in Figure 5C has a conductive layer 321 that functions as a gate, an insulating layer 328 that functions as a gate insulating layer, a semiconductor layer 327 having a channel forming region 327i and a pair of low-resistance regions 327n, a conductive layer 322a connected to one of the pair of low-resistance regions 327n, a conductive layer 322b connected to the other of the pair of low-resistance regions 327n, an insulating layer 325 that functions as a gate insulating layer, a conductive layer 323 that functions as a gate, and an insulating layer 324 covering the conductive layer 323. The insulating layer 328 is located between the conductive layer 321 and the channel forming region 327i. The insulating layer 325 is located between the conductive layer 323 and the channel forming region 327i. Preferably, the transistor 320 is covered by an insulating layer 326. The insulating layer 326 may be included as a component of the transistor 320.

[0300] The conductive layer 322a and the conductive layer 322b are each connected to the low-resistance region 327n via openings provided in the insulating layer 324. Of the conductive layer 322a and the conductive layer 322b, one functions as a source and the other functions as a drain.

[0301] The insulating layer 325 is provided overlapping at least the channel-forming region 327i of the semiconductor layer 327. The insulating layer 325 may also cover the top and side surfaces of a pair of low-resistance regions 327n.

[0302] The transistor 330 shown in Figure 5D has a conductive layer 331 that functions as a gate, an insulating layer 338 that functions as a gate insulating layer, conductive layers 332a and 332b that function as source and drain, a semiconductor layer 337, an insulating layer 335 that functions as a gate insulating layer, and a conductive layer 333 that functions as a gate. The insulating layer 338 is located between the conductive layer 331 and the semiconductor layer 337. The insulating layer 335 is located between the conductive layer 333 and the semiconductor layer 337. Preferably, the transistor 330 is covered by an insulating layer 334. The insulating layer 334 may be included as a component of the transistor 330.

[0303] Transistors 320 and 330 are configured in which a semiconductor layer on which a channel is formed is sandwiched between two gates. The transistors may be driven by connecting the two gates and supplying them with the same signal. Alternatively, the threshold voltage of the transistors may be controlled by applying a potential to control the threshold voltage to one of the two gates and a potential to drive the other gate.

[0304] It is preferable to use a material that does not easily allow impurities such as water and hydrogen to diffuse into at least one layer of the insulating layer covering the transistor. This allows the insulating layer to function as a barrier layer. With such a configuration, the diffusion of impurities from the outside into the transistor can be effectively suppressed, and the reliability of the light-emitting device can be improved.

[0305] It is preferable to use an inorganic insulating film for insulating layers 325, 326, 328, 334, 335, and 338. Examples of inorganic insulating films that can be used include silicon nitride, silicon oxide nitride, silicon oxide, silicon nitride, aluminum oxide, and aluminum nitride. Alternatively, hafnium oxide, yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, and neodymium oxide may also be used. Furthermore, two or more of the above insulating films may be laminated together.

[0306] Materials that can be used for the various conductive layers constituting the light-emitting device include metals such as aluminum, titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum, silver, tantalum, or tungsten, or alloys mainly composed of these materials. Films containing these materials can be used as single layers or in laminated structures. For example, there are single-layer structures of aluminum films containing silicon, two-layer structures of aluminum films laminated on titanium films, two-layer structures of aluminum films laminated on tungsten films, two-layer structures of copper films laminated on copper-magnesium-aluminum alloy films, two-layer structures of copper films laminated on titanium films, two-layer structures of copper films laminated on tungsten films, three-layer structures of titanium films or titanium nitride films with aluminum films or copper films laminated on top and titanium films or titanium nitride films formed on top of those, and three-layer structures of molybdenum films or molybdenum nitride films with aluminum films or copper films laminated on top and molybdenum films or molybdenum nitride films formed on top of those. Furthermore, oxides such as indium oxide, tin oxide, or zinc oxide may be used. In addition, using copper containing manganese is preferable because it improves the controllability of the shape through etching.

[0307] This embodiment can be combined with other embodiments as appropriate.

[0308] (Embodiment 4) In this embodiment, a light-receiving device, a light-emitting device, and a light-emitting apparatus according to one aspect of the present invention will be described with reference to the figures.

[0309] [Example configuration of a light-receiving device] This embodiment describes a photodetector having the function of detecting visible light or near-infrared light. Figures 6A and 6B show an example of a photodetector having a layer containing an organic compound between a pair of electrodes.

[0310] The photodetector shown in Figure 6A has a structure in which a layer 105 containing an organic compound is sandwiched between a first electrode 101 and a second electrode 102. The layer 105 containing the organic compound has at least an active layer.

[0311] Figure 6B shows an example of a laminated structure of the layer 105 containing an organic compound. In this embodiment, the case in which the first electrode 101 functions as an anode and the second electrode 102 functions as a cathode will be explained as an example. The photodetector can detect light incident on the photodetector, generate an electric charge, and extract it as an electric current by driving it with a reverse bias applied between the first electrode 101 and the second electrode 102. The layer 105 containing the organic compound has a structure in which a hole transport layer 116, an active layer 117, and an electron transport layer 118 are sequentially laminated on the first electrode 101. The hole transport layer 116, the active layer 117, and the electron transport layer 118 may each be a single layer or a laminated structure. When the first electrode 101 is the cathode and the second electrode 102 is the anode, the lamination order is reversed.

[0312] The active layer 117 contains a semiconductor. Examples of such semiconductors include inorganic semiconductors such as silicon, and organic semiconductors containing organic compounds. In this embodiment, an example is shown in which an organic semiconductor is used as the semiconductor of the active layer. Using an organic semiconductor is preferable because the light-emitting layer of the light-emitting device and the active layer 117 can be formed using the same method (for example, vacuum deposition), and the manufacturing equipment can be shared.

[0313] The n-type semiconductor material of the active layer 117 is fullerene (for example, C 60 , C 70 Examples include electron-accepting organic semiconductor materials such as fullerene derivatives.

[0314] Furthermore, examples of n-type semiconductor materials include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, naphthalene derivatives, anthracene derivatives, coumarin derivatives, rhodamine derivatives, triazine derivatives, and quinone derivatives.

[0315] Examples of p-type semiconductor materials for the active layer 117 include electron-donating organic semiconductor materials such as copper(II) phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), zinc phthalocyanine (ZnPc), tin phthalocyanine (SnPc), and quinacridone.

[0316] Furthermore, examples of p-type semiconductor materials include carbazole derivatives, thiophene derivatives, furan derivatives, and compounds having an aromatic amine skeleton. In addition, examples of p-type semiconductor materials include naphthalene derivatives, anthracene derivatives, pyrene derivatives, triphenylene derivatives, fluorene derivatives, pyrrole derivatives, benzofuran derivatives, benzothiophene derivatives, indole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, indolocarbazole derivatives, porphyrin derivatives, phthalocyanine derivatives, naphthalocyanine derivatives, quinacridone derivatives, polyphenylenevinylene derivatives, polyparaphenylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, and polythiophene derivatives.

[0317] The HOMO level of electron-donating organic semiconductor materials is preferably higher than that of electron-accepting organic semiconductor materials. The LUMO level of electron-donating organic semiconductor materials is also preferably higher than that of electron-accepting organic semiconductor materials.

[0318] It is preferable to use spherical fullerenes as electron-accepting organic semiconductor materials and organic semiconductor materials with a near-planar shape as electron-donating organic semiconductor materials. Molecules with similar shapes tend to aggregate, and when molecules of the same type aggregate, their molecular orbital energy levels are close, which can improve carrier transport.

[0319] For example, the active layer 117 is preferably formed by co-depositing an n-type semiconductor and a p-type semiconductor. Alternatively, the active layer 117 may have a laminated structure of a layer having an n-type semiconductor and a layer having a p-type semiconductor.

[0320] The first electrode 101 and the second electrode 102 can be made of the same materials as those used for the electrodes of the light-emitting device described in Embodiment 2.

[0321] It is preferable to use a composite material according to one embodiment of the present invention, as described in Embodiment 1, for the hole transport layer 116. In addition, one or more materials that can be used for the hole injection layer 111 and the hole transport layer 112 of the light-emitting device described in Embodiment 2 can be used for the hole transport layer 116. In other words, the hole transport layer 116 can have the same configuration as one or both of the hole injection layer 111 and the hole transport layer 112 of the light-emitting device described in Embodiment 2.

[0322] The electron transport layer 118 can use one or more of the materials that can be used for the electron transport layer 114 and the electron injection layer 115 of the light-emitting device described in Embodiment 2. In other words, the electron transport layer 118 can have the same configuration as one or both of the electron transport layer 114 and the electron injection layer 115 of the light-emitting device described in Embodiment 2.

[0323] [Example configuration of a light-receiving device] In the laminated structure shown in Figures 6A and 6B, by providing a light-emitting layer 113 in addition to the hole transport layer 116, active layer 117, and electron transport layer 118 as the layer 105 containing the organic compound, it can function as a light-receiving device.

[0324] The light-emitting layer 113 is preferably provided between the hole transport layer 116 and the active layer 117, or between the active layer 117 and the electron transport layer 118. Furthermore, it is preferable to provide a buffer layer between the light-emitting layer 113 and the active layer 117.

[0325] Since a single light-emitting and light-receiving device can function as both a light-emitting and light-receiving device, the number of devices required per pixel can be reduced. This facilitates improvements such as higher resolution, higher aperture ratio, and higher resolution in display devices.

[0326] [Example of a light-receiving device configuration] A light-receiving and light-emitting device has both a light-receiving function and a light-emitting function. Below, as an example of a light-receiving and light-emitting device, a display device with a light-receiving function will be described.

[0327] The display device of this embodiment includes a light-receiving device or a light-receiving / light-receiving device in addition to a light-emitting device.

[0328] The display device of this embodiment has the function of displaying an image using a light-emitting device (and a light-receiving device). In other words, the light-emitting device (and the light-receiving device) functions as a display device.

[0329] The light-emitting device functions as a display device (also called a display element). Preferably, an EL device such as an OLED (Organic Light Emitting Diode) or QLED (Quantum-dot Light Emitting Diode) is used as the light-emitting device. Alternatively, an LED such as a microLED (Light Emitting Diode) can also be used as the light-emitting device. The light-emitting device using the composite material according to one embodiment of the present invention, as described in Embodiment 1, has high light extraction efficiency and reliability, and is therefore suitably used in a display device according to one embodiment of the present invention.

[0330] The display device of this embodiment has the function of detecting light using a light-receiving device or a light-emitting / receiving device.

[0331] When a light-receiving device or a light-emitting / receiving device is used as an image sensor, the display device of this embodiment can capture images. For example, the display device of this embodiment can be used as a scanner.

[0332] For example, an image sensor can be used to acquire biometric data such as fingerprints and palm prints. In other words, a biometric authentication sensor can be built into the display device. By having the display device incorporate the biometric authentication sensor, the number of components in the electronic device can be reduced compared to when a separate biometric authentication sensor is provided, enabling miniaturization and weight reduction of the electronic device.

[0333] Furthermore, when a light-receiving device or a light-emitting / receiving device is used as a touch sensor, the display device of this embodiment can detect the proximity or contact with an object.

[0334] As the light-receiving device, for example, a pn-type or pin-type photodiode can be used. In particular, it is preferable to use an organic photodiode having a layer containing an organic compound as the light-receiving device. Organic photodiodes are easy to thin, lighten, and enlarge in area, and also offer a high degree of freedom in shape and design, so they can be applied to various display devices. The light-receiving device using the composite material of one aspect of the present invention described in this embodiment can be suitably used in the display device of one aspect of the present invention.

[0335] A display device according to one aspect of the present invention has an organic EL device as a light-emitting device and an organic photodiode as a light-receiving device. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device.

[0336] A light-receiving and light-emitting device can be fabricated by adding an active layer of a light-receiving device to the configuration of the light-emitting device described above. For example, the active layer of a pn-type or pin-type photodiode can be used for the light-receiving and light-emitting device. In particular, it is preferable to use an active layer of an organic photodiode having a layer containing an organic compound for the light-receiving and light-emitting device. A light-receiving and light-emitting device using a composite material according to one aspect of the present invention described in this embodiment can be suitably used in a display device according to one aspect of the present invention.

[0337] Specifically, light-emitting and receiving devices can be fabricated by combining organic EL devices and organic photodiodes. For example, a light-emitting and receiving device can be fabricated by adding an active layer of an organic photodiode to the stacked structure of an organic EL device. Furthermore, by fabricating a light-emitting and receiving device by combining an organic EL device and an organic photodiode, the number of film deposition steps can be suppressed by depositing layers that can share a common structure with the organic EL device in a single process.

[0338] In one embodiment of the present invention, a display device can utilize a light-emitting device as a light source for a sensor. Therefore, it is not necessary to provide a separate light-receiving unit and light source from the display device, and the number of components in the electronic device can be reduced.

[0339] Next, we will describe the detailed configuration of the display device. Figures 6C and 6D will be used to mainly explain the specific structure of the display device, and Figures 7A to 7C will be used to mainly explain the specific functions of the display device.

[0340] [Display device 500A] Figure 6C shows a cross-sectional view of the display device 500A.

[0341] The display device 500A has a light-receiving device 510, a light-emitting device 590, a transistor 531, and a transistor 532, etc., between a pair of substrates (substrate 551 and substrate 552).

[0342] The light-emitting device 590 has a pixel electrode 591, a buffer layer 512, a light-emitting layer 593, a buffer layer 514, and a common electrode 515 stacked in this order. The buffer layer 512 may have a hole injection layer and / or a hole transport layer. The light-emitting layer 593 contains an organic compound. The buffer layer 514 may have an electron injection layer and / or an electron transport layer. The light-emitting device 590 has the function of emitting visible light. The display device 500A may further have a light-emitting device 590 that has the function of emitting infrared light.

[0343] The light-receiving device 510 has a pixel electrode 511, a buffer layer 512, an active layer 513, a buffer layer 514, and a common electrode 515 stacked in this order. In the light-receiving device 510, the buffer layer 512 functions as a hole transport layer. The active layer 513 contains an organic compound. The light-receiving device 510 has the function of detecting visible light. In the light-receiving device 510, the buffer layer 514 functions as an electron transport layer. The light-receiving device 510 may also have the function of detecting infrared light.

[0344] The buffer layer 512, buffer layer 514, and common electrode 515 are layers common to the light-emitting device 590 and the light-receiving device 510, and are provided across them.

[0345] In this embodiment, it is described that in both the light-emitting device 590 and the light-receiving device 510, the pixel electrode 511 functions as the anode and the common electrode 515 functions as the cathode. In other words, by driving the light-receiving device 510 with a reverse bias applied between the pixel electrode 511 and the common electrode 515, the display device 500A can detect the light incident on the light-receiving device 510, generate an electric charge, and extract it as an electric current.

[0346] The pixel electrode 511, buffer layer 512, active layer 513, light-emitting layer 593, buffer layer 514, and common electrode 515 may each be a single-layer structure or a stacked structure.

[0347] The pixel electrodes 511 and 591 are located on the insulating layer 533. The ends of the pixel electrode 511 and the ends of the pixel electrode 591 are covered by the insulating layer 534, respectively. Adjacent pixel electrodes 511 and 591 are electrically insulated (or electrically isolated) from each other by the insulating layer 534.

[0348] An organic insulating film is preferred as the insulating layer 534. Examples of materials that can be used as the organic insulating film include acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. The insulating layer 534 may have the function of transmitting visible light or the function of blocking visible light.

[0349] The materials and film thickness of the pair of electrodes in the light-receiving device 510 and the light-emitting device 590 can be made identical. This reduces the manufacturing cost of the display device and simplifies the manufacturing process.

[0350] In the light-receiving device 510, the buffer layer 512, the active layer 513, and the buffer layer 514, located between the pixel electrode 511 and the common electrode 515, can also be called organic layers (layers containing organic compounds). The pixel electrode 511 preferably has the function of reflecting visible light. The common electrode 515 has the function of transmitting visible light. Furthermore, if the light-receiving device 510 is configured to detect infrared light, the common electrode 515 has the function of transmitting infrared light. In addition, it is preferable that the pixel electrode 511 has the function of reflecting infrared light.

[0351] The light-receiving device 510 has the function of detecting light. Specifically, the light-receiving device 510 is a photoelectric conversion device (also called a photoelectric conversion element) that receives light 522 incident from outside the display device 500A and converts it into an electrical signal. Light 522 can also be defined as light reflected by an object from the light-emitting device 590. Alternatively, light 522 may be incident on the light-receiving device 510 via a lens or the like provided on the display device 500A.

[0352] In the light-emitting device 590, the buffer layer 512, light-emitting layer 593, and buffer layer 514, located between the pixel electrode 591 and the common electrode 515, respectively, can be collectively referred to as the EL layer. The EL layer includes at least the light-emitting layer 593. The pixel electrode 591 preferably has the function of reflecting visible light. The common electrode 515 also has the function of transmitting visible light. If the display device 500A has a light-emitting device that emits infrared light, the common electrode 515 also has the function of transmitting infrared light. Furthermore, it is preferable that the pixel electrode 591 has the function of reflecting infrared light.

[0353] The light-emitting device 590 has the function of emitting visible light. Specifically, the light-emitting device 590 is an electroluminescent device that emits light towards the substrate 552 by applying a voltage between the pixel electrode 591 and the common electrode 515 (see light 521).

[0354] The pixel electrode 511 of the light-receiving device 510 is electrically connected to the source or drain of the transistor 531 through an opening provided in the insulating layer 533.

[0355] The pixel electrode 591 of the light-emitting device 590 is electrically connected to the source or drain of the transistor 532 through an opening provided in the insulating layer 533.

[0356] Transistors 531 and 532 are in contact with each other on the same layer (substrate 551 in Figure 6C).

[0357] Preferably, at least a portion of the circuit electrically connected to the light-receiving device 510 is formed using the same material and process as the circuit electrically connected to the light-emitting device 590. This allows for a thinner display device and simplifies the manufacturing process compared to forming the two circuits separately.

[0358] It is preferable that the light-receiving device 510 and the light-emitting device 590 are each covered with a protective layer 595. In Figure 6C, the protective layer 595 is provided in contact with the common electrode 515. By providing the protective layer 595, it is possible to suppress the ingress of impurities such as water into the light-receiving device 510 and the light-emitting device 590, thereby improving the reliability of the light-receiving device 510 and the light-emitting device 590. Furthermore, the protective layer 595 and the substrate 552 are bonded together by an adhesive layer 553.

[0359] A light-shielding layer 554 is provided on the surface of substrate 552 that faces substrate 551. The light-shielding layer 554 has openings at positions that overlap with the light-emitting device 590 and at positions that overlap with the light-receiving device 510.

[0360] Here, the light-receiving device 510 detects the light emitted by the light-emitting device 590 that has been reflected by the object. However, there are cases where the light emitted by the light-emitting device 590 is reflected within the display device 500A and enters the light-receiving device 510 without passing through the object. The light-shielding layer 554 can suppress the effects of such stray light. This reduces noise and improves the sensitivity of the sensor using the light-receiving device 510.

[0361] As the light-shielding layer 554, a material that blocks light emission from the light-emitting device can be used. Preferably, the light-shielding layer 554 absorbs visible light. As the light-shielding layer 554, for example, a black matrix can be formed using a metal material or a resin material containing a pigment (such as carbon black) or dye. The light-shielding layer 554 may also have a laminated structure of at least two layers of a red color filter, a green color filter, and a blue color filter.

[0362] [Display device 500B] Figure 6D shows a cross-sectional view of the display device 500B. Note that in the description of the display device 500B, the same configuration as that of the display device 500A described earlier may be omitted.

[0363] The display device 500B includes a light-emitting device 590B, a light-emitting device 590G, and a light-receiving device 580SR.

[0364] The light-emitting device 590B has a pixel electrode 591B, a buffer layer 512, a light-emitting layer 593B, a buffer layer 514, and a common electrode 515 stacked in this order. The light-emitting device 590B has the function of emitting blue light 521B. The light-emitting device 590B is electrically connected to the transistor 532B.

[0365] The light-emitting device 590G has a pixel electrode 591G, a buffer layer 512, a light-emitting layer 593G, a buffer layer 514, and a common electrode 515 stacked in this order. The light-emitting device 590G has the function of emitting green light 521G. The light-emitting device 590G is electrically connected to the transistor 532G.

[0366] The light-receiving device 580SR has a pixel electrode 511, a buffer layer 512, an active layer 513, a light-emitting layer 593R, a buffer layer 514, and a common electrode 515 stacked in this order. The light-receiving device 580SR has the function of emitting red light 521R and the function of detecting light 522. The light-receiving device 580SR is electrically connected to the transistor 531.

[0367] [Display device 500C] The display device 500C shown in Figure 7A includes a substrate 551, a substrate 552, a light receiving device 510, a light-emitting device 590R, a light-emitting device 590G, a light-emitting device 590B, and a functional layer 555, etc.

[0368] The light-emitting devices 590R, 590G, 590B, and 510 are located between substrate 551 and substrate 552. Light-emitting devices 590R, 590G, and 590B emit red (R), green (G), or blue (B) light, respectively.

[0369] The display device 500C has a plurality of pixels arranged in a matrix. Each pixel has one or more subpixels. Each subpixel has one light-emitting device. For example, a pixel can have a configuration with three subpixels (three colors: R, G, B, or three colors: yellow (Y), cyan (C), and magenta (M)), or a configuration with four subpixels (four colors: R, G, B, and white (W), or four colors: R, G, B, and Y). Furthermore, each pixel has a light-receiving device 510. The light-receiving device 510 may be provided for all pixels or for some pixels. Also, a single pixel may have multiple light-receiving devices 510.

[0370] Figure 7A shows how a finger 520 touches the surface of the substrate 552. A portion of the light emitted by the light-emitting device 590G is reflected at the contact point between the substrate 552 and the finger 520. A portion of the reflected light is then incident on the light-receiving device 510, which can detect that the finger 520 has come into contact with the substrate 552. In other words, the display device 500C can function as a touch panel.

[0371] The functional layer 555 includes circuits for driving the light-emitting devices 590R, 590G, and 590B, and a circuit for driving the light-receiving device 510. The functional layer 555 is provided with switches, transistors, capacitors, wiring, etc. However, when the light-emitting devices 590R, 590G, 590B, and the light-receiving device 510 are driven in a passive matrix manner, the configuration may omit one or both of the switches and transistors.

[0372] [Display device 500D] The display device 500D shown in Figure 7B includes a light-emitting device 590IR in addition to the configuration illustrated in Figure 7A. The light-emitting device 590IR is a light-emitting device that emits infrared light (IR). In other words, the display device 500D has a configuration comprising a light-emitting device that emits visible light, a light-emitting device that emits infrared light, and a light-receiving device. In this case, it is preferable that the light-receiving device 510 can receive at least the infrared light (IR) emitted by the light-emitting device 590IR. It is even more preferable that the light-receiving device 510 can receive both visible light and infrared light.

[0373] As shown in Figure 7B, when the finger 520 touches the substrate 552, the infrared light IR emitted from the light-emitting device 590IR is reflected by the finger 520, and a portion of this reflected light is incident on the light-receiving device 510, thereby allowing the position information of the finger 520 to be obtained.

[0374] [Display device 500E] The display device 500E shown in Figure 7C includes a light-emitting device 590B, a light-emitting device 590G, and a light-receiving device 580SR. The light-receiving device 580SR has the function of a light-emitting device that emits red (R) light and the function of a photoelectric conversion device that receives visible light. In other words, the display device 500E is configured to include a light-emitting device that emits visible light and a light-receiving device that emits visible light and receives visible light. Figure 7C shows an example in which the light-receiving device 580SR receives green (G) light emitted by the light-emitting device 590G. The light-receiving device 580SR may also receive blue (B) light emitted by the light-emitting device 590B. Furthermore, the light-receiving device 580SR may receive both green and blue light.

[0375] For example, it is preferable for the light-receiving device 580SR to receive light with a shorter wavelength than the light it emits. The light-receiving device 580SR may also be configured to receive light with a longer wavelength than the light it emits (e.g., infrared light). The light-receiving device 580SR may also be configured to receive light with a wavelength similar to the light it emits, but in that case, it may also receive the light it emits, which may reduce its luminescence efficiency. Therefore, it is preferable for the light-receiving device 580SR to be configured such that the peaks of its emission spectrum and the peaks of its absorption spectrum do not overlap as much as possible.

[0376] Furthermore, the light emitted by the light-receiving device is not limited to red light. Nor is the light emitted by the light-receiving device limited to a combination of green and blue light. For example, the light-receiving device may emit green or blue light and receive light of a different wavelength than the light it emits.

[0377] In this way, by having the light-emitting and light-receiving device 580SR serve as both a light-emitting and light-receiving device, the number of devices arranged in a single pixel can be reduced. Therefore, it becomes easier to increase the resolution, aperture ratio, and overall resolution of the display device.

[0378] This embodiment can be combined with other embodiments as appropriate.

[0379] (Embodiment 5) In this embodiment, an electronic device according to one aspect of the present invention will be described with reference to the figures.

[0380] Examples of electronic devices include television equipment, monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, personal digital assistants, audio playback devices, large game machines such as pachinko machines, biometric authentication devices, and inspection equipment.

[0381] The electronic device of this embodiment has a light-emitting device according to one aspect of the present invention in its display unit, and therefore has high luminous efficiency and high reliability. However, the electronic device according to one aspect of the present invention is not limited to having a light-emitting device according to one aspect of the present invention, but may also have a light-receiving device according to one aspect of the present invention, or a light-receiving and light-emitting device according to one aspect of the present invention.

[0382] The display unit of the electronic device in this embodiment can display video with a resolution of, for example, Full HD, 4K2K, 8K4K, 16K8K, or higher. The screen size of the display unit can be 20 inches or more diagonally, 30 inches or more diagonally, 50 inches or more diagonally, 60 inches or more diagonally, or 70 inches or more diagonally.

[0383] Because the electronic device according to one aspect of the present invention is flexible, it can be incorporated along the curved surfaces of the interior or exterior walls of a house or building, or the interior or exterior of an automobile.

[0384] Furthermore, an electronic device according to one aspect of the present invention may have a secondary battery, and it is preferable that the secondary battery can be charged using contactless power transmission.

[0385] Examples of secondary batteries include lithium-ion secondary batteries such as lithium polymer batteries (lithium-ion polymer batteries) that use a gel-like electrolyte, nickel-metal hydride batteries, nickel-cadmium batteries, organic radical batteries, lead-acid batteries, air secondary batteries, nickel-zinc batteries, and silver-zinc batteries.

[0386] An electronic device according to one aspect of the present invention may have an antenna. By receiving a signal with the antenna, the display unit can display images or information. Furthermore, if the electronic device has an antenna and a secondary battery, the antenna may be used for contactless power transmission.

[0387] The electronic device of this embodiment may have sensors (including those with the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0388] The electronic device of this embodiment can have a variety of functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, a function to execute various software (programs), a wireless communication function, a function to read programs or data recorded on a recording medium, and so on.

[0389] Figure 8A shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7101. Here, the housing 7101 is shown supported by a stand 7103.

[0390] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000.

[0391] The television device 7100 shown in Figure 8A can be operated using the operation switches on the housing 7101 and a separate remote control unit 7111. Alternatively, the display unit 7000 may be equipped with a touch sensor, and the device can be operated by touching the display unit 7000 with a finger or the like. The remote control unit 7111 may have a display unit that displays information output from the remote control unit 7111. Channels and volume can be controlled and the image displayed on the display unit 7000 can be controlled using the operation keys or touch panel on the remote control unit 7111.

[0392] The television system 7100 is configured to include a receiver and a modem. The receiver can receive general television broadcasts. Furthermore, by connecting to a wired or wireless communication network via the modem, it is possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0393] Figure 8B shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0394] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000.

[0395] Figures 8C and 8D show examples of digital signage.

[0396] The digital signage 7300 shown in Figure 8C includes a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, and a microphone, etc.

[0397] Figure 8D shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0398] In Figures 8C and 8D, a light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000.

[0399] The larger the display area 7000, the more information can be provided at once. Furthermore, a larger display area 7000 is more eye-catching, which can, for example, enhance the effectiveness of advertising.

[0400] Applying a touch panel to the display unit 7000 is preferable because it not only allows images or videos to be displayed on the display unit 7000, but also enables intuitive operation by the user. Furthermore, when used for purposes such as providing route information or traffic information, intuitive operation can enhance usability.

[0401] Furthermore, as shown in Figures 8C and 8D, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user. For example, the advertising information displayed on the display unit 7000 can be displayed on the screen of the information terminal 7311 or information terminal 7411. Also, the display on the display unit 7000 can be switched by operating the information terminal 7311 or information terminal 7411.

[0402] Furthermore, the digital signage 7300 or digital signage 7400 can be used to run games using the screen of the information terminal 7311 or information terminal 7411 as the control device (controller). This allows a large number of users to participate in and enjoy the game simultaneously.

[0403] Figures 9A to 9F show an example of a portable information terminal having a flexible display unit 7001.

[0404] The display unit 7001 is manufactured using a light-emitting device according to one embodiment of the present invention. For example, a light-emitting device that can be bent with a radius of curvature of 0.01 mm or more and 150 mm or less can be used. The display unit 7001 may also be equipped with a touch sensor, allowing the portable information terminal to be operated by touching the display unit 7001 with a finger or the like.

[0405] Figures 9A to 9C show examples of foldable portable information terminals. Figure 9A shows the terminal in its unfolded state, Figure 9B shows the terminal in the process of changing between the unfolded and folded states, and Figure 9C shows the portable information terminal 7600 in its folded state. The portable information terminal 7600 offers excellent portability in its folded state and excellent readability due to its seamless, wide display area in its unfolded state.

[0406] The display unit 7001 is supported by three housings 7601 connected by a hinge 7602. By bending the two housings 7601 via the hinge 7602, the portable information terminal 7600 can be reversibly transformed from an unfolded state to a folded state.

[0407] Figures 9D and 9E show an example of a foldable personal digital assistant (PDA). Figure 9D shows the PDA 7650 folded so that the display unit 7001 is on the inside, and Figure 9E shows the PDA 7650 folded so that the display unit 7001 is on the outside. The PDA 7650 has a display unit 7001 and a non-display unit 7651. When the PDA 7650 is not in use, folding it so that the display unit 7001 is on the inside can prevent it from getting dirty or scratched.

[0408] Figure 9F shows an example of a wristwatch-type personal information terminal. The personal information terminal 7800 includes a band 7801, a display unit 7001, input / output terminals 7802, and operation buttons 7803, etc. The band 7801 functions as a housing. The personal information terminal 7800 can also be equipped with a flexible battery 7805. The battery 7805 may be placed on top of, for example, the display unit 7001 or the band 7801.

[0409] The band 7801, the display unit 7001, and the battery 7805 are flexible. Therefore, it is easy to bend the portable information terminal 7800 into a desired shape.

[0410] The operation button 7803 can be assigned various functions, including time setting, power on / off, wireless communication on / off, silent mode activation / deactivation, and power saving mode activation / deactivation. For example, the operating system built into the personal digital assistant 7800 can be used to freely configure the functions of the operation button 7803.

[0411] Furthermore, the application can be launched by touching the icon 7804 displayed on the display unit 7001 with a finger or the like.

[0412] Furthermore, the 7800 portable information terminal is capable of performing standardized short-range wireless communication. For example, it can communicate with a wireless headset to enable hands-free calling.

[0413] Furthermore, the portable information terminal 7800 may also have an input / output terminal 7802. If it has an input / output terminal 7802, it can directly exchange data with other information terminals via a connector. It can also be charged via the input / output terminal 7802. Note that the charging operation of the portable information terminal exemplified in this embodiment may be performed by contactless power transmission without using the input / output terminal.

[0414] Figure 10A shows the exterior of the automobile 9700. Figure 10B shows the driver's seat of the automobile 9700. The automobile 9700 has a body 9701, wheels 9702, windshield 9703, lights 9704, and fog lamps 9705, etc. A light-emitting device according to one aspect of the present invention can be used in the display section of the automobile 9700. For example, a light-emitting device according to one aspect of the present invention can be provided in the display sections 9710 to 9715 shown in Figure 10B. Alternatively, a light-emitting device according to one aspect of the present invention may be used in the lights 9704 or the fog lamps 9705.

[0415] Display units 9710 and 9711 are display devices installed on the windshield of an automobile. In one embodiment of the present invention, the light-emitting device can be made to be in a so-called see-through state, where the other side is visible, by making the electrodes and wiring out of a light-transmitting conductive material. If the display unit 9710 or the display unit 9711 is in a see-through state, it will not obstruct the driver's view when the automobile 9700 is being driven. Therefore, the light-emitting device in one embodiment of the present invention can be installed on the windshield of the automobile 9700. When providing transistors or the like to drive the light-emitting device, it is preferable to use light-transmitting transistors such as organic transistors using organic semiconductor materials or transistors using oxide semiconductors.

[0416] The display unit 9712 is a display device installed in the pillar. For example, by displaying images from an imaging device installed on the vehicle body on the display unit 9712, the field of view obstructed by the pillar can be compensated for. The display unit 9713 is a display device installed in the dashboard. For example, by displaying images from an imaging device installed on the vehicle body on the display unit 9713, the field of view obstructed by the dashboard can be compensated for. In other words, by displaying images from an imaging device installed on the outside of the vehicle, blind spots can be compensated for and safety can be enhanced. Furthermore, by displaying images that compensate for parts that are not visible, safety checks can be performed more naturally and without discomfort.

[0417] Figure 10C shows the interior of a car with bench seats for the driver and passenger. Display unit 9721 is a display device installed in the door. For example, by displaying images from an imaging device installed on the vehicle body on display unit 9721, the view obstructed by the door can be compensated for. Display unit 9722 is a display device installed on the steering wheel. Display unit 9723 is a display device installed in the center of the seat surface of the bench seat. It is also possible to install the display device on the seat surface or backrest and use the display device as a seat heater with the heat generated by the display device as the heat source.

[0418] Display units 9714, 9715, or 9722 can provide various information by displaying navigation information, speedometer, tachometer, mileage, fuel gauge, gear status, air conditioning settings, etc. Furthermore, the display items and layout displayed on the display units can be changed as appropriate to the user's preferences. The above information can also be displayed on display units 9710 to 9713, 9721, and 9723. Additionally, display units 9710 to 9715 and 9721 to 9723 can be used as lighting devices. Furthermore, display units 9710 to 9715 and 9721 to 9723 can also be used as heating devices.

[0419] Furthermore, an electronic device according to one aspect of the present invention has a light-emitting device according to one aspect of the present invention as a light source, and therefore has high luminous efficiency and high reliability. For example, the light-emitting device according to one aspect of the present invention can be used as a light source that emits visible light or near-infrared light. In addition, the light-emitting device according to one aspect of the present invention can also be used as a light source for an illumination device.

[0420] Figure 11A shows a biometric authentication device targeting finger veins, comprising a housing 911, a light source 912, and a detection stage 913. By placing a finger on the detection stage 913, the shape of the veins can be imaged. A light source 912 emitting near-infrared light is installed above the detection stage 913, and an imaging device 914 is installed below it. The detection stage 913 is made of a material that transmits near-infrared light, and the near-infrared light irradiated from the light source 912 and transmitted through the finger can be imaged by the imaging device 914. An optical system may be provided between the detection stage 913 and the imaging device 914. The above device configuration can also be used for biometric authentication devices targeting palm veins.

[0421] A light-emitting device according to one aspect of the present invention can be used as a light source 912. The light-emitting device according to one aspect of the present invention can be installed in a curved shape and can irradiate an object with uniform light. It is particularly preferable that the light-emitting device emits near-infrared light having the strongest peak intensity at wavelengths of 700 nm to 1200 nm. For example, the location of veins can be detected by receiving and imaging light transmitted through a finger or palm. This function can be used for biometric authentication. Furthermore, by combining it with a global shutter system, highly accurate sensing becomes possible even when the subject is moving.

[0422] Furthermore, the light source 912 may have multiple light-emitting units, as shown in Figure 11B, with light-emitting units 915, 916, and 917. Each of the light-emitting units 915, 916, and 917 may emit light at a different wavelength. Also, each can be illuminated at a different time. Therefore, by changing one or both of the wavelength and angle of the irradiated light, different images can be captured in succession, allowing multiple images to be used for authentication and achieving high security.

[0423] Figure 11C shows a biometric authentication device targeting the veins of the palm, comprising a housing 921, operation buttons 922, a detection unit 923, and a light source 924 that emits near-infrared light. By holding a hand over the detection unit 923, the shape of the veins in the palm can be recognized. A PIN or other information can also be entered using the operation buttons. The light source 924 is positioned around the detection unit 923 to illuminate the target object (hand). The reflected light from the target object is then incident on the detection unit 923. A light-emitting device according to one embodiment of the present invention can be used as the light source 924. An imaging device 925 is positioned directly below the detection unit 923 to capture an image of the target object (a complete image of the hand). An optical system may be provided between the detection unit 923 and the imaging device 925. The above device configuration can also be used for a biometric authentication device targeting the veins of the fingers.

[0424] Figure 11D shows a non-destructive testing device comprising a housing 931, an operation panel 932, a transport mechanism 933, a monitor 934, a detection unit 935, and a light source 938 that emits near-infrared light. A light-emitting device according to one embodiment of the present invention can be used as the light source 938. The member to be inspected 936 is transported by the transport mechanism 933 to directly below the detection unit 935. Near-infrared light is irradiated onto the member to be inspected 936 from the light source 938, and the transmitted light is imaged by an imaging device 937 provided inside the detection unit 935. The captured image is displayed on the monitor 934. After that, it is transported to the exit of the housing 931, where defective products are separated and collected. By imaging with near-infrared light, defects and foreign objects inside the member to be inspected can be detected non-destructively and at high speed.

[0425] Figure 11E shows a mobile phone, which includes a housing 981, a display unit 982, operation buttons 983, an external connection port 984, a speaker 985, a microphone 986, a first camera 987, and a second camera 988. The mobile phone is equipped with a touch sensor on the display unit 982. The housing 981 and the display unit 982 are flexible. All operations, such as making a phone call or entering text, can be performed by touching the display unit 982 with a finger or stylus. The first camera 987 can acquire a visible light image, and the second camera 988 can acquire an infrared light image (near-infrared light image). The mobile phone or display unit 982 shown in Figure 11E may have a light-emitting device according to one embodiment of the present invention.

[0426] This embodiment can be combined with other embodiments as appropriate. [Examples]

[0427] In this example, we will describe the results of fabricating and evaluating a light-emitting device according to one embodiment of the present invention.

[0428] In this example, we fabricate a device 1 using a hole injection layer composite material according to one aspect of the present invention, and a comparative device 2 for comparison, and describe the results of evaluation.

[0429] The structures of the two light-emitting devices used in this embodiment are shown in Figure 12, and their specific configurations are shown in Table 1. The chemical formulas of the materials used in this embodiment are shown below.

[0430] [Table 1]

[0431] [ka]

[0432] Fabrication of light-emitting devices The light-emitting device shown in this embodiment has a structure in which, as shown in Figure 12, a first electrode 801 is formed on a substrate 800, and on the first electrode 801, a hole injection layer 811, a hole transport layer 812, a light-emitting layer 813, an electron transport layer 814, and an electron injection layer 815 are sequentially stacked as an EL layer 802, and a second electrode 803 is stacked on the electron injection layer 815.

[0433] First, a first electrode 801 was formed on the substrate 800. The electrode area was 4 mm². 2 The dimensions were set to (2 mm × 2 mm). A glass substrate was used for substrate 800. The first electrode 801 was formed by sputtering indium tin oxide (ITSO) containing silicon oxide to a thickness of 55 nm. In this embodiment, the first electrode 801 functions as an anode.

[0434] Here, as a pretreatment, the surface of the substrate was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. After that, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0435] Next, a hole injection layer 811 was formed on the first electrode 801.

[0436] The hole injection layer 811 of device 1 is deposited in a vacuum deposition apparatus for 10-4 After reducing the pressure to Pa, N,N-bis(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as dchPAF) and an electron acceptor material (OCHD-001) were co-deposited in a weight ratio of dchPAF:OCHD-001 = 1:0.05 and with a film thickness of 10 nm. OCHD-001 is an acceptor material containing fluorine.

[0437] The hole injection layer 811 of comparison device 2 was deposited in a vacuum deposition apparatus for 10 -4 After reducing the pressure to Pa, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF) and OCHD-001 were co-deposited in a weight ratio of PCBBiF:OCHD-001 = 1:0.05 and with a film thickness of 10 nm.

[0438] In both device 1 and comparison device 2, the weight percentage concentration of OCHD-001 in the hole injection layer 811 was 4.8 wt%, and the volume percentage concentration was 3.6 vol%.

[0439] Next, a hole transport layer 812 was formed on the hole injection layer 811.

[0440] The hole transport layer 812 of device 1 was formed by depositing dchPAF to a thickness of 55 nm and N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP) to a thickness of 10 nm.

[0441] The hole transport layer 812 of comparative device 2 was formed by depositing PCBBiF to a thickness of 55 nm and DBfBB1TP to a thickness of 10 nm.

[0442] Next, a light-emitting layer 813 was formed on the hole transport layer 812. The light-emitting layer 813 was formed by co-depositing 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth) as the host material and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02) as the guest material (fluorescent material), with a weight ratio of αN-βNPAnth:3,10PCA2Nbf(IV)-02 = 1:0.015 and a film thickness of 25 nm.

[0443] Next, an electron transport layer 814 was formed on the light-emitting layer 813. The electron transport layer 814 was formed by co-depositing 2-{4-[9,10-di(naphthalene-2-yl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviated as ZADN) and 8-hydroxyquinolinatolithium (abbreviated as Liq) in a weight ratio of ZADN:Liq = 1:1 and with a film thickness of 25 nm.

[0444] Next, an electron injection layer 815 was formed on the electron transport layer 814. The electron injection layer 815 was formed by depositing Liq to a thickness of 1 nm.

[0445] Next, a second electrode 803 was formed on the electron injection layer 815. The second electrode 803 was formed of aluminum by vapor deposition to a thickness of 200 nm. In this embodiment, the second electrode 803 functions as a cathode.

[0446] Through the above process, a light-emitting device was formed on the substrate 800, consisting of an EL layer 802 sandwiched between a pair of electrodes. In the deposition process described above, resistance heating was used for all deposition steps.

[0447] Furthermore, the fabricated light-emitting device was sealed on another substrate (not shown). When sealing with another substrate (not shown), the other substrate (not shown), coated with an adhesive that solidifies with ultraviolet light, was fixed onto substrate 800 in a glove box under a nitrogen atmosphere. The substrates were then bonded together so that the adhesive adhered around the light-emitting device formed on substrate 800. During sealing, 365 nm ultraviolet light at 6 J / cm² was applied. 2 The adhesive was solidified by irradiation and then stabilized by heat treatment at 80°C for 1 hour.

[0448] Figure 13 shows the refractive indices of the low refractive index material (dchPAF) used in the hole injection layer 811 and hole transport layer 812, and the comparative material PCBBiF. A spectroscopic ellipsometer (M-2000U, J.A. Woolam Japan Co., Ltd.) was used for the measurements. As a sample, a film of approximately 50 nm in thickness was deposited on a quartz substrate by vacuum deposition. The figure shows the refractive index of the ordinary ray (n Ordinary) and the refractive index of the extraordinary ray (n Extra-ordinary). The measurement results showed that the refractive index of the layer made of dchPAF at a wavelength of 633 nm was 1.65, and the refractive index of the layer made of PCBBiF at a wavelength of 633 nm was 1.81. Furthermore, the refractive index of the layer made of dchPAF at a wavelength of 460 nm was 1.71, and the refractive index of the layer made of PCBBiF at a wavelength of 460 nm was 1.94.

[0449] Furthermore, the LUMO level of OCHD-001, calculated from cyclic voltammetry (CV) measurements, was -5.27 eV when N,N-dimethylformamide (DMF) was used as the solvent, and -5.40 eV when chloroform was used as the solvent. Also, when DMF was used as the solvent, the HOMO level of dchPAF was -5.36 eV, and the HOMO level of PCBBiF was also -5.36 eV. These results indicate that OCHD-001 exhibits electron-accepting properties for both dchPAF and PCBBiF. For CV measurements, an electrochemical analyzer (manufactured by BAS Corporation, model number: ALS Model 600A or 600C) was used to measure solutions prepared by dissolving the material in a solvent.

[0450] Furthermore, the hole mobility of dchPAF and PCBBiF was measured using impedance spectroscopy (IS method). Specifically, the measurement was performed using an element in which a 500 nm thick layer of dchPAF or PCBBiF was sandwiched between a pair of electrodes made of indium tin oxide (ITSO) and aluminum. The region in contact with ITSO contained OCHD-001 at a concentration of 7 vol%, and the region in contact with aluminum contained molybdenum oxide (MoO3) at a concentration of 17 vol%.

[0451] The measurement results showed that the square root of the electric field strength (V / cm) was 200 (V / cm). 1 / 2 In this case, the hole mobility of the dchPAF is 7.0 × 10⁻¹⁰. -4 cm 2 The value is / Vs, and the hole mobility of PCBBiF is 5.6 × 10⁻⁶. -4 cm 2 The value was / Vs. Thus, dchPAF is a hole-transporting material that can be used in a composite material according to one embodiment of the present invention, and is a monoamine compound having high hole mobility.

[0452] <<Operating characteristics of light-emitting devices>> The operating characteristics of the light-emitting device fabricated in this embodiment were measured. The measurements were performed at room temperature using a spectroradiometer (Topcon SR-UL1R).

[0453] Figure 14 shows the luminance-current density characteristics of the light-emitting device. Figure 15 shows the current efficiency-luminance characteristics of the light-emitting device. Figure 16 shows the current-voltage characteristics of the light-emitting device. Figure 17 shows the external quantum efficiency-luminance characteristics of the light-emitting device.

[0454] Table 2 shows 1000 cd / m². 2 The main initial characteristic values ​​of light-emitting devices in the vicinity are shown.

[0455] [Table 2]

[0456] As shown in Figures 14 to 17 and Table 2, Device 1 was found to have higher luminous efficiency than comparison device 2. Furthermore, Device 1 was found to have good driving characteristics, without a significant increase in driving voltage.

[0457] The dchPAF used in device 1 has a lower refractive index than the PCBBiF used in comparison device 2. As a result, device 1 exhibited higher luminescence efficiency than comparison device 2. Furthermore, in device 1, dchPAF is used in both the hole injection layer 811 and the hole transport layer 812, resulting in a thicker layer with a lower refractive index in the light-emitting device (a larger proportion of the layer with a lower refractive index), which improves the light extraction efficiency.

[0458] In the hole injection layer 811, the concentration of OCHD-001 is low. In other words, the refractive indices of the hole injection layer 811 and the hole transport layer 812 can be considered to be almost the same. This reduces the refractive index step and improves the light extraction efficiency. Furthermore, because the concentration of OCHD-001 in the hole injection layer 811 is low, the absorption of blue light by OCHD-001 can be suppressed, and therefore, in this embodiment, high luminous efficiency was obtained in the blue light-emitting device.

[0459] In dchPAF, 38.5% of the carbon atoms are bonded via sp3 hybrid orbitals relative to the total number of carbon atoms. Even with the use of a material containing a large number of such unsaturated bonds, almost no adverse effects were observed on various properties of device 1 (luminescence efficiency and reliability, which will be discussed later).

[0460] Furthermore, 1000 cd / m² in light-emitting devices 2 The emission spectra in that region are shown in Figure 18. As shown in Figure 18, both device 1 and comparison device 2 showed emission spectra with a maximum peak around 458 nm, originating from the emission of 3,10PCA2Nbf(IV)-02 contained in the light-emitting layer 813.

[0461] Next, reliability tests were conducted on the light-emitting device. The results of the reliability tests are shown in Figure 19. In Figure 19, the vertical axis represents the normalized brightness (%) with the initial brightness set to 100%, and the horizontal axis represents the operating time (h). The reliability tests were conducted at room temperature with a current density of 50 mA / cm². 2 The settings were changed, and the light-emitting device was driven.

[0462] When the initial brightness is set to 100%, the time until the brightness drops to 95% (LT95) was 341 hours for device 1 and 141 hours for comparison device 2. Furthermore, when comparing the brightness after 1000 hours, device 1 maintained 83% of the initial brightness, while comparison device 2 maintained 80% of the initial brightness.

[0463] As described above, in this embodiment, a blue light-emitting device with high luminous efficiency and reliability was fabricated by using a composite material according to one aspect of the present invention. [Examples]

[0464] In this example, we will describe the results of fabricating and evaluating a light-emitting device according to one embodiment of the present invention.

[0465] In this example, we fabricate a device 3 using a hole injection layer composite material according to one aspect of the present invention, and a comparative device 4 for comparison, and describe the results of evaluation.

[0466] The structures of the two light-emitting devices used in this embodiment are shown in Figure 12, and their specific configurations are shown in Table 3. The chemical formulas of the materials used in this embodiment are shown below.

[0467] [Table 3]

[0468] [ka]

[0469] Fabrication of light-emitting devices Regarding the method for fabricating the light-emitting device in this embodiment, the part that is the same as the method for fabricating the light-emitting device in Embodiment 1 can be explained by referring to Embodiment 1.

[0470] The hole injection layer 811 of device 3 is deposited in a vacuum deposition apparatus for 10 -4 After reducing the pressure to Pa, N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as mmtBumTPchPAF) and OCHD-001 were co-deposited in a weight ratio of mmtBumTPchPAF:OCHD-001 = 1:0.1 and with a film thickness of 65 nm.

[0471] The hole injection layer 811 of comparison device 4 was deposited in a vacuum deposition apparatus for 10 -4 After reducing the pressure to Pa, PCBBiF and OCHD-001 were co-deposited in a weight ratio of PCBBiF:OCHD-001 = 1:0.1 and with a film thickness of 70 nm.

[0472] In both device 3 and comparison device 4, the weight percentage concentration of OCHD-001 in the hole injection layer 811 was 9.1 wt%, and the volume percentage concentration was 6.8 vol%.

[0473] In both device 3 and comparative device 4, the hole transport layer 812 was formed by depositing PCBBiF to a thickness of 20 nm.

[0474] The luminescent layer 813 uses 9-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr) as the host material (also known as the first host material), PCBBiF as the assist material (also known as the second host material), and {4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyradinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ) as the guest material (phosphorescent material). 2 The film was formed by co-depositing using O,O') Iridium(III) (abbreviation: [Ir(dmdppr-m5CP)2(dpm)]) with a weight ratio of 9mDBtBPNfpr:PCBBiF:[Ir(dmdppr-m5CP)2(dpm)] = 0.8:0.2:0.1 and a film thickness of 25 nm.

[0475] The electron transport layer 814 was formed by depositing 9mDBtBPNfpr to a thickness of 30 nm and then depositing 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen) to a thickness of 15 nm.

[0476] The electron injection layer 815 was formed by depositing lithium fluoride (LiF) to a thickness of 1 nm.

[0477] Figure 20 shows the refractive indices of the low refractive index material (mmtBumTPchPAF) used in the hole injection layer 811 and the comparative material PCBBiF. A spectroscopic ellipsometer (M-2000U, J.A. Woolam Japan Co., Ltd.) was used for the measurements. As a sample, a film of approximately 50 nm in thickness was deposited on a quartz substrate by vacuum deposition. The figure shows the refractive index of n Ordinary (normal) and n Extra-ordinary (extraordinary). The measurement results showed that the refractive index of the layer made of mmtBumTPchPAF at a wavelength of 633 nm was 1.62, and the refractive index of the layer made of PCBBiF at a wavelength of 633 nm was 1.81. The glass transition temperature of mmtBumTPchPAF is 124°C. In other words, mmtBumTPchPAF is a material with a high glass transition temperature and a low refractive index. By using mmtBumTPchPAF, thermal degradation can be suppressed, enabling device fabrication using high-temperature processes and operation of light-emitting devices at high temperatures.

[0478] As described in Example 1, the LUMO level of OCHD-001 calculated from the CV measurement results was -5.27 eV when N,N-dimethylformamide (DMF) was used as the solvent, and -5.40 eV when chloroform was used as the solvent. Furthermore, when DMF was used as the solvent, the HOMO level of mmtBumTPchPAF was -5.42 eV. From these results, it can be said that OCHD-001 exhibits electron-accepting properties for mmtBumTPchPAF. The CV measurement apparatus was the same as in Example 1.

[0479] <<Operating characteristics of light-emitting devices>> The operating characteristics of the light-emitting device fabricated in this embodiment were measured. The measurements were performed at room temperature using a spectroradiometer (Topcon SR-UL1R).

[0480] Figure 21 shows the luminance-current density characteristics of the light-emitting device. Figure 22 shows the current efficiency-luminance characteristics of the light-emitting device. Figure 23 shows the current-voltage characteristics of the light-emitting device. Figure 24 shows the external quantum efficiency-luminance characteristics of the light-emitting device.

[0481] Table 4 shows 1000 cd / m². 2 The main initial characteristic values ​​of light-emitting devices in the vicinity are shown.

[0482] [Table 4]

[0483] As shown in Table 4, device 3 and comparison device 4 are light-emitting devices that exhibit light of the same chromaticity. As shown in Figures 21 to 24 and Table 4, device 3 was able to achieve higher luminous efficiency with the same chromaticity as comparison device 4, while hardly changing the current-voltage characteristics.

[0484] In Example 1, layers with a low refractive index were used for both the hole injection layer 811 and the hole transport layer 812, but in Example 2, a layer with a low refractive index was used only for the hole injection layer 811. From the results of this example, it was found that high luminescence efficiency can be obtained even when a layer with a low refractive index is applied only to the hole injection layer 811.

[0485] In the light-emitting device of Example 2, the thickness of the hole injection layer 811 is greater than that of the light-emitting device of Example 1. Since the hole injection layer 811 is a highly conductive layer, increasing its thickness can reduce the driving voltage of the light-emitting device. Because OCHD-001 absorbs almost no red light, increasing the thickness of the hole injection layer 811 did not result in a decrease in luminous efficiency.

[0486] In mmtBumTPchPAF, 41.0% of the carbon atoms are bonded via sp3 hybrid orbitals relative to the total number of carbon atoms. Even with the use of a material containing a large number of such unsaturated bonds, almost no adverse effects were observed on various properties of device 3 (luminescence efficiency and reliability, which will be discussed later).

[0487] Furthermore, 1000 cd / m² in light-emitting devices 2The emission spectra in that region are shown in Figure 25. As shown in Figure 25, device 3 exhibited an emission spectrum with a maximum peak around 644 nm, originating from the emission of [Ir(dmdppr-m5CP)2(dpm)] contained in the light-emitting layer 813. Similarly, comparative device 4 exhibited an emission spectrum with a maximum peak around 645 nm.

[0488] Next, reliability tests were conducted on the light-emitting device. The results of the reliability tests are shown in Figure 26. In Figure 26, the vertical axis represents the normalized brightness (%) with the initial brightness set to 100%, and the horizontal axis represents the operating time (h). The reliability tests were conducted at room temperature with a current density of 50 mA / cm². 2 The settings were changed, and the light-emitting device was driven.

[0489] Both device 3 and comparison device 4 showed comparable reliability characteristics, with brightness levels after 520 hours being 88% of the initial brightness.

[0490] From the above, it was found that device 3 has higher luminous efficiency than comparative device 4, while also achieving equivalent reliability.

[0491] (Reference example) This reference example describes a method for synthesizing organic compounds that can be used as the first organic compound described in Embodiment 1. These organic compounds are examples of materials with low refractive index and hole transport properties. Specifically, as shown in Table 5, all of these organic compounds have an orbital refractive index of 1.50 to 1.75 in the blue emission region (455 nm to 465 nm), and an orbital refractive index of 1.45 to 1.70 at 633 nm light, which is normally used to measure refractive index. Also, as shown in Table 5, the ratio of carbon atoms forming bonds in sp3 hybrid orbitals to the total number of carbon atoms in each of these organic compounds is 23% to 55%.

[0492] [Table 5]

[0493] First, we will explain the synthesis method of N,N-bis(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as dchPAF), which is represented by the following structural formula (100).

[0494] [ka]

[0495] 10.6 g (51 mmol) of 9,9-dimethyl-9H-fluoren-2-amine, 18.2 g (76 mmol) of 4-cyclohexyl-1-bromobenzene, 21.9 g (228 mmol) of sodium tert-butoxide, and 255 mL of xylene were placed in a three-necked flask. After degassing under reduced pressure, the flask was purged with nitrogen. This mixture was heated and stirred to approximately 50°C. Then, 370 mg (1.0 mmol) of allyl palladium chloride dimer(II) (abbreviation: [(Allyl)PdCl]2) and 1660 mg (4.0 mmol) of di-tert-butyl (1-methyl-2,2-diphenylcyclopropyl)phosphine (abbreviation: cBRIDP®) were added, and this mixture was heated at 120°C for approximately 5 hours. After that, the flask temperature was reduced to approximately 60°C, and approximately 4 mL of water was added to precipitate a solid. The precipitated solid was filtered off. The filtrate was concentrated, and the resulting solution was purified by silica gel column chromatography. The resulting solution was concentrated to obtain a concentrated toluene solution. This toluene solution was added dropwise to ethanol and reprecipitation occurred. The precipitate was filtered at approximately 10°C, and the resulting solid was dried under reduced pressure at approximately 80°C to obtain 10.1 g of the target white solid in a yield of 40%. The synthesis scheme for dchPAF is shown below.

[0496] [ka]

[0497] Nuclear magnetic resonance spectroscopy of the obtained white solid ( 1 The results of the analysis by 1H-NMR are shown below. From these results, it was confirmed that dchPAF could be synthesized.

[0498] 1 H-NMR.δ(CDCl3):7.60(d,1H,J=7.5Hz),7.53(d,1H,J=8.0Hz),7.37(d,2H,J=7 .5Hz),7.29(td,1H,J=7.5Hz,1.0Hz),7.23(td,1H,J=7.5Hz,1.0Hz),7.19(d,1H ,J=1.5Hz),7.06(m,8H),6.97(dd,1H,J=8.0Hz,1.5Hz),2.41-2.51(brm,2H),1. 79-1.95(m,8H),1.70-1.77(m,2H),1.33-1.45(brm,14H),1.19-1.30(brm,2H).

[0499] Similarly, organic compounds represented by structural formulas (101) to (109) below were synthesized.

[0500] [ka]

[0501] [ka]

[0502] Nuclear magnetic resonance spectroscopy of these organic compounds ( 1 The analysis results (by 1H-NMR) are shown below. The glass transition temperatures are also shown for some of the organic compounds.

[0503] Results for N-[(3',5'-Diter-butyl)-1,1'-Biphenyl-4-yl]-N-(4-Cyclohexylphenyl)-9,9-Dimethyl-9H-Fluorene-2-amine (abbreviation: mmtBuBichPAF), represented by structural formula (101).

[0504] 1H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.57(d,1H,J=8.0Hz),7.44-7.49(m,2H) ,7.37-7.42(m,4H),7.31(td,1H,J=7.5Hz,2.0Hz),7.23-7.27(m,2H),7.15-7.19( m,2H),7.08-7.14(m,4H),7.05(dd,1H,J=8.0Hz,2.0Hz),2.43-2.53(brm,1H),1. 81-1.96(m,4H),1.75(d,1H,J=12.5Hz),1.32-1.48(m,28H),1.20-1.31(brm,1H).

[0505] The glass transition temperature of mmtBuBichPAF, represented by structural formula (101), was 102°C.

[0506] Results for N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF), represented by structural formula (102).

[0507] 1 H-NMR.δ(CDCl3):7.63(d,J=6.6Hz,1H),7.58(d,J=8.1Hz,1H),7.42-7.37(m,4H),7.36-7.09(m,14H),2.55-2.39(m,1H),1.98-1.20(m,51H).

[0508] The glass transition temperature of mmtBumTPchPAF, represented by structural formula (102), was 124°C.

[0509] Results for N-[(3,3',5'-t-butyl)-1,1'-biphenyl-5-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBichPAF), represented by structural formula (103).

[0510] 1H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.56(d,1H,J=8.5Hz),7.37-40(m, 2H),7.27-7.32(m,4H),7.22-7.25(m,1H),7.16-7.19(brm,2H),7.08-7.15 (m,4H),7.02-7.06(m,2H),2.43-2.51(brm,1H),1.80-1.93(brm,4H),1.71 -1.77(brm,1H),1.36-1.46(brm,10H),1.33(s,18H),1.22-1.30(brm,10H).

[0511] The glass transition temperature of mmtBumBichPAF, represented by structural formula (103), was 103°C.

[0512] Results for N-(1,1'-biphenyl-2-yl)-N-[(3,3',5'-tri-t-butyl)-1,1'-biphenyl-5-yl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBioFBi), represented by structural formula (104).

[0513] 1 H-NMR.δ(CDCl3):7.57(d,1H,J=7.5Hz),7.40-7.47(m,2H),7.32-7.39(m,4H),7.27-7.31(m,2H ),7.27-7.24(m,5H),6.94-7.09(m,6H),6.83(brs,2H),1.33(s,18H),1.32(s,6H),1.20(s,9H).

[0514] The glass transition temperature of mmtBumBioFBi, represented by structural formula (104), was 102°C.

[0515] Results for N-(4-tert-butylphenyl)-N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-9,9,-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPtBuPAF), represented by structural formula (105).

[0516] 1 H-NMR.δ(CDCl3):7.64(d,1H,J=7.5Hz),7.59(d,1H,J=8.0Hz),7.38-7.43(m,4H),7.29-7.36(m,8H) ,7.24-7.28(m,3H),7.19(d,2H,J=8.5Hz),7.13(dd,1H,J=1.5Hz,8.0Hz),1.47(s,6H),1.32(s,45H).

[0517] The glass transition temperature of mmtBumTPtBuPAF, represented by structural formula (105), was 123°C.

[0518] Results for N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-02), represented by structural formula (106).

[0519] 1 H-NMR.δ(CDCl3):7.56(d,1H,J=7.4Hz),7.50(dd,1H,J=1.7Hz),7.33-7.46(m,11H),7.27-7.29(m,2H),7.22(dd,1H,J=2.3Hz),7 .15(d,1H,J=6.9Hz),6.98-7.07(m,7H),6.93(s,1H),6.84(d,1H,J=6.3Hz),1.38(s,9H),1.37(s,18H),1.31(s,6H),1.20(s,9H).

[0520] The glass transition temperature of mmtBumTPoFBi-02, represented by structural formula (106), was 126°C.

[0521] Results for N-(4-cyclohexylphenyl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-02), represented by structural formula (107).

[0522] 1 H-NMR.δ(CDCl3):7.62(d,1H,J=7.5Hz),7.56(d,1H,J=8.0Hz),7.50(dd,1H,J=1.7Hz),7.4 6-7.47(m,2H),7.43(dd,1H,J=1.7Hz),7.37-7.39(m,3H),7.29-7.32(m,2H),7.23-7.25(m ,2H),7.20(dd,1H,J=1.7Hz),7.09-7.14(m,5H),7.05(dd,1H,J=2.3Hz),2.46(brm,1H),1. 83-1.88(m,4H),1.73-1.75(brm,1H),1.42(s,6H),1.38(s,9H),1.36(s,18H),1.29(s,9H).

[0523] The glass transition temperature of mmtBumTPchPAF-02, represented by structural formula (107), was 127°C.

[0524] Results for N-(1,1'-biphenyl-2-yl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-03), represented by structural formula (108).

[0525] 1 H-NMR.δ(CDCl3):7.55(d,1H,J=7.4Hz),7.50(dd,1H,J=1.7Hz),7.42-7.43(m,3H),7.27-7.39(m,10H),7.18-7.25(m,4H),7.00-7.12 (m,4H),6.97(dd,1H,J=6.3Hz,1.7Hz),6.93(d,1H,J=1.7Hz),6.82(dd,1H,J=7.3Hz,2.3Hz),1.37(s,9H),1.36(s,18H),1.29(s,6H).

[0526] Results for N-(4-cyclohexylphenyl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-03), represented by structural formula (109).

[0527] 1 H-NMR.δ(CDCl3):7.62(d,1H,J=7.5Hz),7.56(d,1H,J=8.6Hz),7.51(dd,1H,J=1.7 Hz),7.48(dd,1H,J=1.7Hz),7.46(dd,1H,J=1.7Hz),7.42(dd,1H,J=1.7Hz),7.37-7 .39(m,4H),7.27-7.33(m,2H),7.23-7.25(m,2H),7.05-7.13(m,7H),2.46(brm,1H) ),1.83-1.90(m,4H),1.73-1.75(brm,1H),1.41(s,6H),1.37(s,9H),1.35(s,18H). [Explanation of symbols]

[0528] 101: First electrode, 102: Second electrode, 103a: EL layer, 103b: EL layer, 103c: EL layer, 103: EL layer, 104: Charge generation layer, 105: Layer containing organic compound, 111: Hole injection layer, 112: Hole transport layer, 113: Light-emitting layer, 114: Electron transport layer, 115: Electron injection layer, 116: Hole transport layer, 117: Active layer, 118: Electron transport layer, 201: Substrate, 202a: Insulating layer, 202b: Insulating layer, 202: Insulating layer, 203B: Light-emitting device, 203G: Light-emitting device, 203R: Light-emitting device, 203W: Light-emitting device, 204: Insulating layer, 205: Substrate Board, 206B: Color filter, 206G: Color filter, 206R: Color filter, 207: Space, 208: Adhesive layer, 209: Black matrix, 210: Transistor, 211: First electrode, 212G: Conductive layer, 212R: Conductive layer, 213B: EL layer, 213G: EL layer, 213R: EL layer, 213: EL layer, 215: Second electrode, 220B: Optical distance, 220G: Optical distance, 220R: Optical distance, 301: First substrate, 302: Pixel section, 303: Circuit section, 304a: Circuit section, 304b: Circuit section, 305: Sealing material, 306: Second substrate, 30 7: Wiring, 308: FPC, 309: Transistor, 310: Transistor, 311: Transistor, 312: Transistor, 313: First electrode, 314: Insulating layer, 315: EL layer, 316: Second electrode, 318: Space, 320: Transistor, 321: Conductive layer, 322a: Conductive layer, 322b: Conductive layer, 323: Conductive layer, 324: Insulating layer, 325: Insulating layer, 326: Insulating layer, 327i: Channel formation region, 327n: Low resistance region, 327: Semiconductor layer, 328: Insulating layer, 330: Transistor, 331: Conductive layer, 332a: Conductive layer, 332b: Conductive Electrode layer, 333: conductive layer, 334: insulating layer, 335: insulating layer, 337: semiconductor layer, 338: insulating layer, 401: first electrode, 402: EL layer, 403: second electrode, 405: insulating layer, 406: conductive layer, 407: adhesive layer, 416: conductive layer, 420: substrate, 422: adhesive layer, 423: barrier layer, 424: insulating layer, 490a: substrate, 490b: substrate, 490c: barrier layer, 500A: display device, 500B: display device, 500C: display device, 500D: display device, 500E: display device, 510: light receiving device, 511: pixel electrode, 512: buffer layer, 513: active layer,514: Buffer layer, 515: Common electrode, 520: Finger, 521: Light, 521B: Light, 521G: Light, 521R: Light, 522: Light, 531: Transistor, 532B: Transistor, 532G: Transistor, 532: Transistor, 533: Insulating layer, 534: Insulating layer, 551: Substrate, 552: Substrate, 553: Adhesive layer, 554: Light-shielding layer, 555: Functional layer, 580SR: Light-receiving / light-emitting device, 590B: Light-emitting device, 590G: Light-emitting device, 590IR: Light-emitting device, 590R: Light-emitting device, 590: Light-emitting device, 591B: Pixel electrode, 591G: Image 591: Pixel electrode, 593B: Light-emitting layer, 593G: Light-emitting layer, 593R: Light-emitting layer, 593: Light-emitting layer, 595: Protective layer, 800: Substrate, 801: First electrode, 802: EL layer, 803: Second electrode, 811: Hole injection layer, 812: Hole transport layer, 813: Light-emitting layer, 814: Electron transport layer, 815: Electron injection layer, 911: Housing, 912: Light source, 913: Detection stage, 914: Imaging device, 915: Light-emitting unit, 916: Light-emitting unit, 917: Light-emitting unit, 921: Housing, 922: Operation button, 923: Detection unit, 924: Light source, 925: Imaging device, 931: Housing, 932: 933: Control panel, 934: Transport mechanism, 935: Monitor, 936: Component under inspection, 937: Imaging device, 938: Light source, 981: Housing, 982: Display unit, 983: Operation buttons, 984: External connection port, 985: Speaker, 986: Microphone, 987: First camera, 988: Second camera, 7000: Display unit, 7001: Display unit, 7100: Television device, 7101: Housing, 7103: Stand, 7111: Remote control, 7200: Notebook personal computer, 7211: Housing, 7212: Keyboard, 7213: Pointy 7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 7600: Portable information terminal, 7601: Enclosure, 7602: Hinge, 7650: Portable information terminal, 7651: Non-display section, 7800: Portable information terminal, 7801: Band, 7802: Input / output terminal, 7803: Operation button, 7804: Icon, 7805: Battery, 9700: Automobile, 9701: Body, 9702: Wheels, 9703: Windshield9704: Lights, 9705: Fog lights, 9710: Display unit, 9711: Display unit, 9712: Display unit, 9713: Display unit, 9714: Display unit, 9715: Display unit, 9721: Display unit, 9722: Display unit, 9723: Display unit,

Claims

[Claim 1] It comprises a first organic compound and a second organic compound, The proportion of carbon atoms in the first organic compound that form bonds with sp3 hybrid orbitals relative to the total number of carbon atoms is 23% or more and 55% or less. The second organic compound is a composite material for a hole injection layer, containing fluorine.

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