Light-emitting device

Abstract

Provided is a light-emitting device that has excellent characteristics. This light-emitting device has an emissive layer between a pair of electrodes. The emissive layer contains a first organic compound, a second organic compound, and a luminescent substance. The first organic compound is an organic compound having a heteroaromatic ring, the second organic compound is an aromatic compound comprising an aromatic hydrocarbon, and one or both of the first organic compound and the second organic compound contain one or more deuterium atoms.

Description

Light-emitting devices

[0001] One aspect of the present invention relates to organic compounds, organic semiconductor elements, light-emitting devices, light-receiving devices, photodiode sensors, display modules, lighting modules, display devices, electronic equipment, lighting devices, and electronic devices. However, one aspect of the present invention is not limited to the above-mentioned technical fields. The technical fields of one aspect of the invention disclosed herein relate to products, methods, or methods of manufacturing. Alternatively, one aspect of the present invention relates to processes, machines, manufacturers, or compositions of matter. Therefore, more specifically, examples of the technical fields of one aspect of the present invention disclosed herein include semiconductor devices, display devices, liquid crystal display devices, lighting devices, energy storage devices, memory devices, imaging devices, methods for driving them, or methods for manufacturing them.

[0002] The practical application of organic electroluminescent devices (organic EL elements), such as light-emitting devices, light-receiving devices, and light-receiving / receiving devices, which utilize electroluminescence using organic compounds, is progressing.

[0003] For example, the basic configuration of a light-emitting device consists of an organic compound layer (EL layer) containing a light-emitting material sandwiched between a pair of electrodes. By applying a voltage to this device, carriers are injected, and by utilizing the recombination energy of these carriers, light emission can be obtained from the light-emitting material.

[0004] Furthermore, the basic configuration of a photodetector consists of an organic compound layer (active layer) containing a light-emitting material sandwiched between a pair of electrodes. This device absorbs light energy and generates carriers, thereby obtaining electrons from the photoelectric conversion material.

[0005] For example, a functional panel is known in which pixels provided in the display area are equipped with light-emitting elements (light-emitting devices) and photoelectric conversion elements (light-receiving devices) (Patent Document 1).

[0006] Furthermore, while the characteristics of organic EL devices have improved remarkably, they are still insufficient to meet the high demands for all characteristics, including efficiency and durability. For example, a technology for substituting hydrogen atoms in a host material with deuterium atoms (deuteration) has been disclosed (Patent Document 2).

[0007] Furthermore, research and development are underway to find organic EL elements with even better characteristics (see, for example, Non-Patent Document 1).

[0008] WO2020 / 152556 special table 2013-503860

[0009] Hiroshi Noguchi, et al., "Orientational Polarization Phenomena of Polar Molecules and Interface Properties of Organic Thin Film Devices," Journal of the Vacuum Society of Japan, 2015, Vol. 58, No. 3.

[0010] One aspect of the present invention aims to provide a novel light-emitting device. Another aspect of the present invention aims to provide a light-emitting device with high luminous efficiency and good reliability.

[0011] One aspect of the present invention aims to provide an organic EL device with a long operating life. Another aspect of the present invention aims to provide a novel organic EL device. Another aspect of the present invention aims to reduce the manufacturing cost of an organic EL device. Another aspect of the present invention aims to provide a light-emitting device, electronic device, or lighting device with low power consumption.

[0012] Furthermore, the description of these problems does not preclude the existence of other problems. Also, one aspect of the present invention does not need to solve all of these problems. Other problems will naturally become clear from the description in the specification, drawings, claims, etc., and it is possible to extract other problems from the description in the specification, drawings, claims, etc.

[0013] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a fluorescent light-emitting material, and one or both of the first organic compound and the second organic compound contain one or more deuterium atoms.

[0014] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a fluorescent light-emitting material, the first organic compound being an organic compound having a heteroaromatic ring, and one or both of the first and second organic compounds having one or more deuterium atoms.

[0015] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance, the second organic compound being an aromatic compound consisting of an aromatic hydrocarbon, and one or both of the first organic compound and / or the second organic compound having one or more deuterium atoms.

[0016] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance, the first organic compound being an organic compound having a heteroaromatic ring, the second organic compound being an aromatic compound consisting of an aromatic hydrocarbon, and one or both of the first and second organic compounds having one or more deuterium atoms.

[0017] In the above invention, the light-emitting material is a fluorescent light-emitting material, which is the light-emitting device.

[0018] In the above invention, the first organic compound and the second organic compound are light-emitting devices having one or more deuterium atoms.

[0019] In the above invention, the light-emitting device is a compound having an anthracene skeleton in its molecular structure, either the first organic compound or the second compound.

[0020] In the above invention, the first organic compound and the second compound are light-emitting devices having an anthracene skeleton in their molecular structure.

[0021] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance, the first organic compound being an organic compound having a heteroaromatic ring containing anthracene, the second organic compound being an organic compound having a heteroaromatic ring containing anthracene, the first organic compound and the second organic compound having different molecular structures, and one or both of the first organic compound and the second organic compound being a light-emitting device having one or more deuterium atoms.

[0022] One aspect of the present invention provides a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance, the first organic compound being an aromatic compound consisting of an aromatic hydrocarbon having anthracene, the second organic compound being an aromatic compound consisting of an aromatic hydrocarbon having anthracene, the first organic compound and the second organic compound having different molecular structures, and one or both of the first organic compound and the second organic compound being a light-emitting device having one or more deuterium atoms.

[0023] One aspect of the present invention is a light-emitting device having a light-emitting layer between a pair of electrodes, wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance, the first organic compound being represented by the following general formula (G1), the second organic compound being represented by the following general formula (G2), and one or both of the first organic compound and the second organic compound having one or more deuterium atoms.

[0024]

[0025] In the above formula, R １ ~R ８ Each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a cyano group, Ar １ and Ar ２ Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms, and Ar３ and Ar ４ each independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and Ar ３ and Ar ４ one of them is a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. n and m each independently represent an integer of 0 or 1 to 4.

[0026]

[0027] In the above formula, R １１ to R １８ each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a cyano group, and Ar １１ and Ar １２ each independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, and Ar １３ and Ar １４ each independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. p and q each independently represent an integer of 0 or 1 to 4.

[0028] Or, another aspect of the present invention is an electronic device having the above light-emitting device, or the above light-receiving device, and a sensor, an operation button, a speaker, or a microphone.

[0029] Or, another aspect of the present invention is a lighting device having the above light-emitting device, or the above light-receiving device, and a housing.

[0030] According to one aspect of the present invention, a novel light-emitting device can be provided. Further, according to one aspect of the present invention, a light-emitting device having high luminous efficiency and good reliability can be provided.

[0031] Furthermore, according to one aspect of the present invention, a novel organic EL device can be provided. Furthermore, according to one aspect of the present invention, an organic EL device with a long operating life can be provided. Furthermore, according to one aspect of the present invention, the manufacturing cost of the organic EL device can be reduced. Furthermore, according to one aspect of the present invention, a light-emitting device, electronic device, or lighting device with low power consumption can be provided.

[0032] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims.

[0033] Figures 1A and 1B are schematic diagrams of the light-emitting device. Figure 2 is a diagram showing the capacitance-voltage characteristics of the measuring device 1. Figure 3 is a diagram showing the current density-voltage characteristics of the measuring device 1. Figures 4A, 4B, 4C, 4D, and 4E are diagrams illustrating the configuration of the light-emitting device. Figures 5A and 5B are top views and cross-sectional views of the light-emitting device. Figures 6A, 6B, 6C, 6D, 6E, 6F, and 6G are top views showing examples of pixel configurations. Figures 7A, 7B, 7C, 7D, 7E, 7F, 7G, 7H, and 7I are top views showing examples of pixel configurations. Figures 8A and 8B are perspective views showing examples of display module configurations. Figures 9A and 9B are cross-sectional views showing examples of display device configurations. Figure 10 is a perspective view showing an example of display device configuration. Figure 11 is a cross-sectional view showing an example of display device configuration. Figure 12 is a cross-sectional view showing an example of display device configuration. Figures 13A, 13B, and 13C are cross-sectional views showing examples of the configuration of a display device. Figure 14 is a cross-sectional view showing an example of the configuration of a display device. Figures 15A, 15B, and 15C are cross-sectional views showing examples of the configuration of a display device. Figures 16A, 16B, 16C, and 16D are diagrams showing an example of an electronic device. Figures 17A, 17B, 17C, 17D, 17E, and 17F are diagrams showing an example of an electronic device. Figures 18A, 18B, 18C, 18D, 18E, 18F, and 18G are diagrams showing an example of an electronic device. Figure 19 is a diagram showing the device structure of the light-emitting device 1. Figure 20 is a diagram showing the brightness-current density characteristics of the light-emitting device 1. Figure 21 is a diagram showing the brightness-voltage characteristics of the light-emitting device 1. Figure 22 is a diagram showing the current efficiency-brightness characteristics of the light-emitting device 1. Figure 23 is a diagram showing the current density-voltage characteristics of the light-emitting device 1. Figure 24 shows the power efficiency-luminance characteristics of light-emitting device 1. Figure 25 shows the external quantum efficiency-luminance characteristics of light-emitting device 1. Figure 26 shows the field emission spectrum of light-emitting device 1. Figure 27 shows the normalized luminance time variation characteristics of light-emitting device 1. Figure 28 shows the luminance-current density characteristics of light-emitting device 2. Figure 29 shows the luminance-voltage characteristics of light-emitting device 2. Figure 30 shows the current efficiency-luminance characteristics of light-emitting device 2.Figure 31 shows the current density-voltage characteristics of the light-emitting device 2. Figure 32 shows the power efficiency-luminance characteristics of the light-emitting device 2. Figure 33 shows the external quantum efficiency-luminance characteristics of the light-emitting device 2. Figure 34 shows the field emission spectrum of the light-emitting device 2. Figure 35 shows the normalized luminance time variation characteristics of the light-emitting device 2.

[0034] The embodiments of the present invention will be described in detail below with reference to the drawings. However, the present invention is not limited to the following description, and its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention should not be interpreted as being limited to the contents of the embodiments shown below.

[0035] In this specification, "deuterated organic compound" refers to an organic compound in which, when focusing on hydrogen atoms (including deuterium) at specific positions within the organic compound, the proportion of deuterium (including deuterium) is greater than the natural abundance of deuterium. Preferably, this proportion is sufficiently greater than the natural abundance. "Sufficiently" means, for example, that 7.5 mol% or more is deuterated. The deuteration of an organic compound can be confirmed by methods such as nuclear magnetic resonance (NMR), mass spectrometry, or a combination thereof.

[0036] Please note that the positions, sizes, and ranges of each component shown in the drawings may not represent their actual positions, sizes, and ranges for the sake of ease of understanding. Therefore, the disclosed invention is not necessarily limited to the positions, sizes, and ranges disclosed in the drawings.

[0037] Furthermore, in this specification and other documents, when describing the structure of the invention using drawings, reference numerals that refer to the same thing will be used consistently across different drawings.

[0038] (Embodiment 1) This embodiment describes a light-emitting device according to one aspect of the present invention, in which a plurality of organic compounds, including an organic compound containing deuterium, are used as the host material for the light-emitting layer.

[0039] <Example of Light-Emitting Device Configuration> Figure 1A is a schematic cross-sectional view of a light-emitting device 10 according to one embodiment of the present invention. The light-emitting device 10 has a pair of electrodes (a first electrode 101 and a second electrode 102) and an organic compound layer 103 provided between the pair of electrodes. The organic compound layer 103 has at least a light-emitting layer 113. In this embodiment 1, the organic compound layer 103 also has a hole transport layer 112.

[0040] Furthermore, the organic compound layer 103 shown in Figure 1A has functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115, in addition to the light-emitting layer 113.

[0041] In this embodiment, the first electrode 101 is described as the anode and the second electrode 102 as the cathode, but the configuration of the light-emitting device 10 is not limited to this. In other words, the first electrode 101 may be the cathode and the second electrode 102 as the anode, and the stacking order of the layers between the electrodes may be reversed. That is, the stacking order from the anode side may be the hole injection layer 111, the hole transport layer 112, the light-emitting layer 113, the electron transport layer 114, and the electron injection layer 115.

[0042] The configuration of the organic compound layer 103 is not limited to the configuration shown in Figure 1A, and may include at least one selected from the hole injection layer 111, hole transport layer 112, electron transport layer 114, and electron injection layer 115. Alternatively, the organic compound layer 103 may include a functional layer that has functions such as reducing the hole or electron injection barrier, improving hole or electron transport, inhibiting hole or electron transport, or suppressing quenching by electrodes. Each functional layer may be a single layer or a configuration in which multiple layers are stacked.

[0043] Figure 1B is a schematic cross-sectional view showing an example of the light-emitting layer 113 shown in Figure 1A. The light-emitting layer 113 shown in Figure 1B comprises two types of host materials 118 (organic compound 118_1 and organic compound 118_2) and a guest material 119 (luminescent substance).

[0044] As the guest material 119, it is preferable to use a substance that emits fluorescence (hereinafter also referred to as a fluorescent compound) among luminescent organic compounds. In particular, by using a fluorescent compound as the luminescent material for blue devices, it is possible to provide a light-emitting device with good reliability.

[0045] Furthermore, in the light-emitting layer 113, the host material 118 is present in the largest amount by weight, and the guest material 119 is dispersed within the host material 118. When a fluorescent compound is used as the guest material, the lowest triplet excitation level (T) of the host material 118 in the light-emitting layer 113 is set. １ The level is the T of the guest material 119 of the light-emitting layer 113. １ A level lower than the current level is preferable because it enhances the luminescence efficiency through TTA (Triple-Triple Annihilation).

[0046] In one embodiment of the present invention, the host material 118 comprises at least two organic compounds, represented by organic compound 118_1 and organic compound 118_2. Furthermore, the host material 118 of the light-emitting layer 113 (organic compound 118_1 and organic compound 118_2) comprises at least one deuterium atom. In other words, at least one, preferably both, of organic compound 118_1 and organic compound 118_2 is a compound containing deuterium.

[0047] By mixing two different organic compounds, 118_1 and 118_2, as the host material 118, the film quality is stabilized and heat resistance is improved when a film is formed. Furthermore, by using a deuterated compound as the host material 118, a highly reliable light-emitting device can be obtained that achieves high luminescence efficiency while suppressing degradation.

[0048] For example, automotive displays and the like require the ability to withstand prolonged exposure to high temperatures, making the light-emitting device according to one embodiment of the present invention particularly suitable. Furthermore, the configuration of the light-emitting layer according to one embodiment of the present invention can suppress degradation caused by the heating process used to remove moisture during processing using photolithography, thereby improving design flexibility.

[0049] For example, the host material 118 preferably contains an organic compound having a heteroaromatic ring. By using organic compounds having different heteroaromatic rings for organic compound 118_1 and organic compound 118_2, a light-emitting device with a low driving voltage and low power consumption can be provided. Furthermore, this configuration makes it easier to maintain carrier balance, thus providing a highly efficient light-emitting device.

[0050] Furthermore, it is preferable that the host material 118 includes an aromatic compound consisting of an aromatic hydrocarbon. By using different aromatic hydrocarbon compounds for organic compound 118_1 and organic compound 118_2, a highly reliable light-emitting device can be provided.

[0051] Furthermore, for example, organic compound 118_1 may be an organic compound having a heteroaromatic ring, and organic compound 118_2 may be an aromatic compound consisting of an aromatic hydrocarbon. By including an organic compound having a heteroaromatic ring, it is possible to maintain carrier balance, thereby achieving high efficiency and low power consumption, and by including an aromatic compound consisting of an aromatic hydrocarbon, a light-emitting device with good reliability can be provided.

[0052] Furthermore, when organic compound 118_1 is an organic compound having an anthracene skeleton and a heteroaromatic ring, and organic compound 118_2 is an aromatic compound consisting of an aromatic hydrocarbon having an anthracene skeleton, the carrier balance of the light-emitting layer is improved, making it possible to provide a device with high luminescence efficiency, which is preferable. In particular, when the skeleton in which the orbitals of the lowest unoccupied molecular orbital (LUMO) level responsible for electron transport are distributed is an anthracene skeleton, it is preferable because high electron injection into the light-emitting layer and high electron transport of the light-emitting layer can be achieved.

[0053] Furthermore, when an aromatic compound consisting of aromatic hydrocarbons is used as the host material 118, the electron injection properties into the light-emitting layer and the electron transport properties of the light-emitting layer are improved. However, if excessive electron injection into the light-emitting layer occurs, the carrier balance of the light-emitting layer may be disrupted, and the recombination region may be extremely biased towards the anode side of the light-emitting layer. It is preferable to use both an organic compound having a heteroaromatic ring and an aromatic compound consisting of aromatic hydrocarbons in the light-emitting layer because the hole injection properties into the light-emitting layer are improved and the balance between holes and electrons in the light-emitting layer is improved. When the highest occupied molecular orbital (HOMO) level of the organic compound having a heteroaromatic ring is lower than the HOMO level of the aromatic compound consisting of aromatic hydrocarbons, the electron mobility of the organic compound having a heteroaromatic ring is suppressed, electron injection into the light-emitting layer is suppressed, and the carrier balance of the light-emitting layer is improved. On the other hand, if the HOMO level of an organic compound having a heteroaromatic ring is higher than that of an aromatic compound consisting of aromatic hydrocarbons, the hole mobility of the organic compound having a heteroaromatic ring increases, leading to increased hole implantation into the light-emitting layer and improving the carrier balance of the light-emitting layer.

[0054] Furthermore, when using an organic compound having a heteroaromatic ring for organic compound 118_1 and an aromatic compound consisting of an aromatic hydrocarbon for organic compound 118_2, it is preferable because the organic compound 118_1, which is an organic compound having a heteroaromatic ring, contains deuterium, thus improving reliability compared to an aromatic compound consisting of an aromatic hydrocarbon, which has high reliability.

[0055] On the other hand, when organic compound 118_1, which is an aromatic compound composed of aromatic hydrocarbons, contains deuterium, the carbon-deuterium bond in the excited state is more stable than the carbon-practicum bond in the excited state, and the reaction that produces degraded products from the excited state is suppressed, thus improving reliability.

[0056] Furthermore, when both organic compound 118_1, which is an organic compound having a heteroaromatic ring, and organic compound 118_2, which is an aromatic compound consisting of aromatic hydrocarbons, are used, the carrier balance of the light-emitting layer improves, the exciton density increases, and degradation tends to accelerate. However, when both organic compound 118_1, which is an organic compound having a heteroaromatic ring, and organic compound 118_2, which is an aromatic compound consisting of aromatic hydrocarbons, contain deuterium, degradation can be sufficiently suppressed even when the exciton density is high, resulting in a synergistic effect and a dramatic improvement in reliability, which is preferable.

[0057] <Examples of organic compounds that can be used in the host material 118> For the host material 118 that can be used in a light-emitting device according to one aspect of the present invention, for example, the organic compounds described below can be used. Note that if the organic compound represented by general formula (G1) and the organic compound represented by general formula (G2) have deuterium, R ｘ substituents represented by (x is a natural number), and Ar ｙ Any of the hydrogen atoms in the substituent represented by (where y is a natural number) may be deuterium.

[0058] <<Examples of organic compounds having heteroaromatic rings>> For example, as an organic compound that can be used in the host material 118, an organic compound represented by general formula (G1) can be used.

[0059]

[0060] In the above formula, R １ ~R ８ Each of these independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a cyano group. １ and Ar ２ Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms, and Ar ３ and Ar４ Each of these independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, Ar ３ and Ar ４ The group is a heteroaryl group having 1 to 30 carbon atoms, either single-substituted or unsubstituted. n and m each independently represent an integer from 0 to 4. All hydrogen atoms in general formula (G1) may independently be light hydrogen or deuterium.

[0061] <<Examples of aromatic compounds consisting of aromatic hydrocarbons>> For example, as an organic compound that can be used in the host material 118, an organic compound represented by general formula (G2) can be used.

[0062]

[0063] In the above formula, R １１ ~R １８ Each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a cyano group, Ar １１ and Ar １２ Each of these independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, and Ar １３ and Ar １４ Each of these independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. p and q independently represent 0 or an integer from 1 to 4. All hydrogen atoms in general formula (G2) may independently be light hydrogen or deuterium.

[0064] In the following, in the general formula (G1), R ｘ (x is a natural number) or Ar ｙ Specific examples of substituents represented by (where y is a natural number) are shown below.

[0065] Examples of linear or branched 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, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, and 1-ethylpropyl group.

[0066] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, bicyclo[2,2,2]octyl group, decahydronaphthyl group, and adamantyl group.

[0067] Examples of aryl groups having 6 to 30 carbon atoms include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, biphenyl-2-yl group (o-biphenyl group), biphenyl-3-yl group (m-biphenyl group), biphenyl-4-yl group (p-biphenyl group), 1-naphthyl group, 2-naphthyl group, phenylnaphthyl group, naphthylphenyl group, terphenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, quaterphenyl group, spirobifluorenyl group, phenanthryl group, anthryl group, binaphthylphenyl group, and fluoranthenyl group.

[0068] Furthermore, if the aryl group has substituents, examples of substituents include halogens, cyano groups, C1 to C6 alkyl groups, C2 to C6 alkenyl groups, C2 to C6 alkynyl groups, C1 to C6 alkoxy groups, C3 to C10 trialkylsilyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, phenantrenyl groups, and the like.

[0069] Examples of heteroaryl groups having 1 to 30 carbon atoms include 1,3,5-triazine-2-yl group, 1,2,4-triazine-3-yl group, pyrimidine-4-yl group, pyrazine-2-yl group, 2-pyridyl group, 3-pyridyl group, 4-pyridyl group, carbazolyl group, dibenzofuranyl group, dibenzothiophenyl group, benzonaphthofuranyl group, benzonaphthothiophenyl group, indolocarbazolyl group, benzoflocarbazolyl group, benzothienocarbazolyl group, indenocarbazolyl group, and dibenzocarbazolyl group.

[0070] Furthermore, if the heteroaryl group has substituents, examples of such substituents include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenantrenyl groups.

[0071] Examples of arylene groups having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorene-diyl group, acenaphthene-diyl group, anthracene-diyl group, phenanthrene-diyl group, terphenyl-diyl group, triphenylene-diyl group, phenanthrene-diyl group, tetracene-yl group, benzanthracene-diyl group, pyrene-diyl group, and spirobi[9H-fluorene]-diyl group.

[0072] Furthermore, if the arylene group has substituents, examples of substituents include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenantrenyl groups.

[0073] Examples of heteroarylene groups having 1 to 30 carbon atoms include pyrimidine-diyl group, pyrazine-diyl group, pyridazine-diyl group, triazine-diyl group, bipyridine-diyl group, phenanthroline-diyl group, quinoxaline-diyl group, dibenzoquinoxaline-diyl group, quinazoline-diyl group, benzoquinazoline-diyl group, dibenzoquinazoline-diyl group, imidazo-diyl group, triazole-diyl group, and oxadiazole-diyl group. Examples include yl group, benzimidazole-diyl group, phlodiazine-diyl group, benzophropyrimidine-diyl group, thiophene-diyl group, furan-diyl group, benzothiophene-diyl group, benzofuran-diyl group, dibenzothiophene-diyl group, dibenzofuran-diyl group, benzonaphthothiophene-diyl group, benzonaphthofuran-diyl group, dinaphthothiophene-diyl group, and dinaphthofuran-diyl group.

[0074] Furthermore, if any of the above heteroarylene groups have substituents, examples of substituents include C1 to C4 alkyl groups, C3 to C6 cycloalkyl groups, or phenyl groups, naphthyl groups, and phenantrenyl groups.

[0075] In the following, in the general formula (G2), R ｘ (x is a natural number) or Ar ｙ Specific examples of substituents represented by (where y is a natural number) are shown below.

[0076] Examples of linear or branched 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, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, and 1-ethylpropyl group.

[0077] Examples of cycloalkyl groups having 3 to 10 carbon atoms include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclononyl group, cyclodecyl group, norbornyl group, bicyclo[2,2,2]octyl group, decahydronaphthyl group, and adamantyl group.

[0078] Examples of aryl groups having 6 to 30 carbon atoms include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, biphenyl-2-yl group (o-biphenyl group), biphenyl-3-yl group (m-biphenyl group), biphenyl-4-yl group (p-biphenyl group), 1-naphthyl group, 2-naphthyl group, phenylnaphthyl group, naphthylphenyl group, terphenyl group, fluorenyl group, 9,9-dimethylfluorenyl group, quaterphenyl group, spirobifluorenyl group, phenanthryl group, anthryl group, binaphthylphenyl group, and fluoranthenyl group.

[0079] Furthermore, if the aryl group has substituents, examples of substituents include halogens, cyano groups, C1 to C6 alkyl groups, C2 to C6 alkenyl groups, C2 to C6 alkynyl groups, C1 to C6 alkoxy groups, C3 to C10 trialkylsilyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenanthreneyl groups.

[0080] Examples of arylene groups having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorene-diyl group, acenaphthene-diyl group, anthracene-diyl group, phenanthrene-diyl group, terphenyl-diyl group, triphenylene-diyl group, phenanthrene-diyl group, tetracene-yl group, benzanthracene-diyl group, pyrene-diyl group, and spirobi[9H-fluorene]-diyl group.

[0081] Furthermore, if the arylene group has substituents, examples of such substituents include C1 to C10 alkyl groups, C3 to C10 cycloalkyl groups, phenyl groups, naphthyl groups, and phenanthreneyl groups.

[0082] Furthermore, the spontaneous polarization (SOP) that occurs in vapor-deposited films of organic compounds such as light-emitting layers will be explained below.

[0083] In vapor-deposited films of organic compounds such as luminescent layers, the permanent electric dipole moments of molecules can be oriented, sometimes resulting in spontaneous polarization (SOP). Furthermore, if this spontaneous polarization is biased in the direction of film thickness, a giant surface potential (GSP) may be generated. Since GSP increases proportionally to film thickness, a slope of GSP (GSP_slope) exists as a physical property of the layer. GSP_slope is a parameter expressed as ΔV / Δd, where ΔV (mV) is the change in surface potential relative to Δd (nm) in film thickness. In other words, the GSP per unit film thickness is called GSP-slope. Furthermore, if the surface potential increases with increasing film thickness, the GSP_slope will be positive; conversely, if the surface potential decreases with increasing film thickness, the GSP_slope will be negative.

[0084] Furthermore, when layers with different GSP_slope are stacked, an electric charge is generated at the interface, and this interface charge affects the device characteristics. Therefore, in a light-emitting device, by selecting the materials used for each layer while considering the slope (GSP_slope) of the giant surface potential (GSP) of the light-emitting layer 113 and the layers surrounding the light-emitting layer 113, the interface charge can be controlled, improving the luminous efficiency of the light-emitting device or reducing the driving voltage.

[0085] For example, in the case of a light-emitting device in which the anode is placed on the substrate side (referred to as a forward-stacked device), by configuring the device so that the GSP_slope of the light-emitting layer 113, especially the GSP_slope of the host material 118 which has a large weight ratio, is smaller than the GSP_slope of the hole transport layer 112, hole injection from the hole transport layer 112 to the light-emitting layer 113 is suppressed. Therefore, the light-emitting region can be localized near the interface between the light-emitting layer 113 and the hole transport layer 112, making it possible to create a light-emitting device that effectively utilizes triplet-triplet annihilation (TTA). In other words, in a forward-stacked device, it is possible to improve the light-emitting efficiency by effectively utilizing triplet-triplet annihilation. Furthermore, in the case of a sequentially stacked device, by configuring the device so that the GSP_slope of the light-emitting layer 113 is larger than the GSP_slope of the hole transport layer 112, hole injection into the light-emitting layer becomes possible, thereby lowering the driving voltage of the light-emitting device. To compare the GPS-slope, one should compare the GPS-slope of a layer fabricated using the host material with the GSP-slope of a layer fabricated using the hole transport layer material. The method for determining the GSP_slope is described later.

[0086] On the other hand, in the case of a light-emitting device in which the cathode is placed on the substrate side (referred to as an inverted stacking device), by configuring the device so that the GSP_slope of the light-emitting layer 113, especially the GSP_slope of the host material 118 which has a large weight ratio, is larger than the GSP_slope of the hole transport layer 112, hole injection from the hole transport layer 112 to the light-emitting layer 113 is suppressed. Therefore, it is possible to localize the light-emitting region near the interface between the light-emitting layer 113 and the hole transport layer 112, and to create a light-emitting device that effectively utilizes triplet-triplet annihilation (TTA). Furthermore, in the case of an inverted stacking device, by configuring the device so that the GSP_slope of the light-emitting layer 113 is smaller than the GSP_slope of the hole transport layer 112, hole injection into the light-emitting layer becomes possible, and thus the driving voltage of the light-emitting device can be lowered.

[0087] To compare GPS_slope, one should compare the GPS_slope of a layer made using a host material with the GSP-slope of a layer made using a hole transport layer material. When multiple types of host materials are mixed in the light-emitting layer, the above-mentioned effect can be obtained if the GSP_slope of a layer made using any one of the host materials is larger or smaller than the GSP_slope of a layer made using a hole transport layer material. More preferably, the GSP_slope of a layer mixed with multiple types of host materials should be compared with the GSP_slope of a layer made using a hole transport layer material. It is also preferable to compare the GSP_slope of each layer made using each of the multiple types of host materials with the GSP_slope of a layer made using a hole transport layer material. In that case, the above effect can be enhanced if all GSP_slope values ​​in each layer are larger or smaller than the GSP_slope values ​​of the layer fabricated using the hole transport layer material. The method for determining the GSP_slope is described below.

[0088] <Method for determining GSP_slope> Here, we will explain the method for determining the GSP_slope of a film formed by vacuum deposition of an organic compound.

[0089] First, we will explain how to calculate GSP_slope in a configuration where the carriers accumulating at the interface are holes. The phenomenon in which the surface potential of a deposited film increases in proportion to the film thickness is called giant surface potential, as mentioned above. Generally, the slope when the surface potential of a deposited film measured by Kelvin probe is plotted in the direction of film thickness is discussed as the magnitude of the giant surface potential, i.e., GSP_slope (mV / nm). However, when two different layers are stacked, the charge density (mC / m) accumulated at the interface... ２ By utilizing the fact that ) changes in relation to GSP, GSP_slope can be estimated.

[0090] Non-patent document 1 shows that when organic thin films with different spontaneous polarizations (thin film 1 and thin film 2, where thin film 1 is on the anode side and thin film 2 is on the cathode side, and the anode is located on the substrate side) are stacked and a voltage is applied, the following equation holds true if the carriers accumulated at the interface are holes.

[0091]

[0092]

[0093] In equation (1), σ ｉｆ＿ｈ Q is the interfacial charge density. ｉｆ is the interfacial charge, S is the surface area, V is the surface area. ｉ V is the hole injection voltage. ｂｉ d is the threshold voltage, ２ ε is the film thickness of thin film 2. ２ V is the dielectric constant of thin film 2. ｉ , V ｂｉ This can be estimated from the capacitance-voltage characteristics of the device. Furthermore, the dielectric constant is the refractive index n. ｏ The square of (633 nm) can be used. In this way, V estimated from the capacitance-voltage characteristics ｉ , V ｂｉ And the dielectric constant ε of thin film 2 calculated from the refractive index. ２ , and the film thickness d of thin film 2 ２ Therefore, using equation (1), the interfacial charge density σ ｉｆ＿ｈ It is possible to find this.

[0094] Next, in equation (2), σ ｉｆ＿ｈ P is the interfacial charge density. ｎ ε is the spontaneous polarization of the thin film n in the direction normal to the substrate. ｎ V is the dielectric constant of the thin film n. ｎ d is the potential of the film surface, ｎ n is the thickness of the thin film. And the potential (V) of the film surface. ｎ ) film thickness (d ｎ The GSP_slope can be calculated from the value obtained by dividing by (1) above. Here, the interface charge density σ ｉｆ＿ｈ Since this can be determined, the GSP_slope of thin film 1 can be estimated by using a material with a known GSP_slope as thin film 2 and adopting an appropriate dielectric constant.

[0095] Therefore, as thin film 2, tris(8-quinolinolato)aluminum (abbreviated as Alq) is used, which has a known GSP_slope of 48 (mV / nm). ３The following is an example of how a measurement device 1 was fabricated using the above method and the GSP_slope of 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB) was determined.

[0096] The device structure of measurement device 1 is shown in Table 1. The cathode from layer 1_1 of measurement device 1 was formed by vacuum deposition from the anode side, with the substrate temperature at room temperature and the deposition rate from 0.2 nm / s to 0.6 nm / s. Deposition was carried out without stopping the deposition process while forming one layer. In measurement device 1, layer 2_1 corresponds to thin film 1, and layer 3_1 corresponds to thin film 2. OCHD-003 is an organic compound that has electron acceptor properties.

[0097] When fabricating the measurement device, the deposition rate of each layer is preferably 3 nm / min to 600 nm / min. Furthermore, the film thickness of each layer in the measurement device is preferably 3 nm to 500 nm, and more preferably 50 nm to 300 nm.

[0098] Furthermore, the capacitance-voltage characteristics of the measuring device 1 are shown in Figure 2.

[0099]

[0100] Table 2 shows the Hole injection voltage V of the measuring device 1, which was determined using Figure 2 and equations (1) and (2). ｉ , threshold voltage V ｂｉ , interfacial charge density σ ｉｆ＿ｈ , GSP_slope and the refractive index n of the NPB used in the calculation ｏ and Alq ３ refractive index n ｏ This shows the results. The refractive index was measured using a spectroscopic ellipsometer (M-2000U, manufactured by J.A. Woolam Japan Co., Ltd.).

[0101]

[0102] Furthermore, it has almost the same configuration as the measurement device 1, Alq ３A measurement device 2 with a film thickness of only 80 nm was fabricated, and it was confirmed that the hole injection voltage in each device was shifted to a lower voltage than that of measurement device 1. In other words, in such a device, the holes are injected first, and Alq ３ This suggests that charge is accumulating at the interface. Furthermore, using measurement device 2, we performed an estimation of GSP_slope in the same way as with measurement device 1 and confirmed that the same result was obtained.

[0103] Furthermore, the threshold voltage V can be obtained from the capacitance-voltage characteristics. ｂｉ If it is difficult to determine, the threshold voltage of the current density-voltage characteristic may be used.

[0104] Figure 3 shows the current density-voltage characteristics of the measuring device 1.

[0105] V calculated from current density-voltage characteristics ｂｉ The voltage was 2.0V, which was the same value as the one calculated from the capacitance-voltage characteristics.

[0106] Thus, Alq, whose membrane GSP_slope is known ３ The GSP_slope can be estimated by fabricating a device by stacking a film formed with the organic compound for which the GSP_slope is to be determined, and then measuring its capacitance-voltage characteristics.

[0107] In the above explanation, we described a method for calculating GSP_slope in a configuration where the carriers accumulated at the interface are holes. However, when calculating the GSP_slope of an organic film in a configuration where the carriers accumulated at the interface are electrons, it can be calculated similarly using the following equations (3) and (4). Note that in the following equations (3) and (4), σ ｉｆ＿ｅ This is the interfacial charge density.

[0108]

[0109]

[0110] It is preferable to select the organic compounds to be used in each layer of the light-emitting device, taking into consideration the GSP_slope of the vapor-deposited film of the organic compound measured in advance by the measurement method described above.

[0111] In some cases, light-emitting devices use layers co-deposited with multiple types of organic compounds. Since the GSP_slope of a co-deposited layer changes depending on the combination and mixing ratio of the organic compounds, it is ideal to measure the GSP_slope of films co-deposited with the same combination and mixing ratio of organic compounds in advance, and then select the organic compounds considering this GSP_slope. However, this method requires fabricating different co-deposited films for each combination or mixing ratio of organic compounds and measuring the GSP_slope for each, making the experiments for selecting organic compounds complicated.

[0112] Therefore, in a light-emitting device, if one layer contains multiple types of organic compounds, it is preferable to select the organic compounds by considering the average value of the GSP_slope of the deposited film of each organic compound, which has been measured in advance, as the GSP_slope of that layer. This makes it relatively easy to select organic compounds that take GSP_slope into consideration.

[0113] However, even if a single layer contains multiple types of organic compounds, if their content differs significantly, the GSP_slope of the vapor-deposited film of the organic compound with the highest content among the multiple types of organic compounds can be considered as the GSP_slope of that layer, and the selection of organic compounds can be performed accordingly. For example, if a single layer contains two types of organic compounds, and the content of one organic compound is less than 20% by weight of the total, that organic compound can be judged as a minor component of that layer, and the other, more abundant organic compound can be judged as the main component of that layer, and the GSP_slope of the vapor-deposited film of that main component can be considered as the GSP_slope of that layer. Also, if a single layer contains three or four types of organic compounds, and the content of one organic compound is less than 20% by weight of the total, that organic compound can be judged as a minor component of that layer, and the remaining organic compounds can be judged as the main components of that layer, and the average value of the GSP_slope of the vapor-deposited films of each main component can be considered as the GSP_slope of that layer.

[0114] <Basic Structure of Light-Emitting Devices> Below, the basic structure of light-emitting devices will be explained in more detail using Figures 4A to 4E. Figure 4A shows a light-emitting device with a structure (single structure) having an organic compound layer (also called an EL layer) containing a light-emitting layer between a pair of electrodes. Specifically, it has a structure in which an organic compound layer 103 is sandwiched between a first electrode 101 and a second electrode 102.

[0115] Furthermore, Figure 4B shows a light-emitting device with a laminated structure (tandem structure) having multiple (two layers in Figure 4B) organic compound layers (103a, 103b) between a pair of electrodes, and a charge generation layer 106 between the organic compound layers. A light-emitting device with a tandem structure can realize a highly efficient light-emitting device without changing the amount of current.

[0116] The charge generation layer 106 has the function of injecting electrons into one organic compound layer (103a or 103b) and holes into the other organic compound layer (103b or 103a) when a potential difference is created between the first electrode 101 and the second electrode 102. Therefore, in Figure 4B, 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 106 into the organic compound layer 103a and holes are injected into the organic compound layer 103b.

[0117] Furthermore, from the viewpoint of light extraction efficiency, it is preferable that the charge generation layer 106 is transparent to visible light (specifically, the transmittance of visible light to the charge generation layer 106 is 40% or more). In addition, the charge generation layer 106 can function even if its conductivity is lower than that of the first electrode 101 and the second electrode 102.

[0118] Figure 4C shows the laminated structure of the organic compound layer 103 of a light-emitting device according to one embodiment of the present invention. In this case, the first electrode 101 functions as an anode and the second electrode 102 functions as a cathode. The organic compound layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially laminated on the first electrode 101. The light-emitting layer 113 may be a configuration in which multiple light-emitting layers with different emission colors are laminated. For example, a light-emitting layer containing a red light-emitting substance, a light-emitting layer containing a green light-emitting substance, and a light-emitting layer containing a blue light-emitting substance may be laminated, or laminated via a layer having a carrier transport material. Alternatively, a combination of a light-emitting layer containing a yellow light-emitting substance and a light-emitting layer containing a blue light-emitting substance may be used. However, the laminated structure of the light-emitting layer 113 is not limited to the above. For example, the light-emitting layer 113 may be configured by stacking multiple light-emitting layers of the same emission color. For example, it may be a structure in which a first light-emitting layer containing a blue light-emitting substance and a second light-emitting layer containing a blue light-emitting substance are stacked, or stacked via a layer having a carrier transport material. In the case of a configuration in which multiple light-emitting layers of the same emission color are stacked, reliability can be increased compared to a single-layer configuration. Also, even when there are multiple light-emitting layers as in the tandem structure shown in Figure 4B, each light-emitting layer is stacked sequentially from the anode side as described above. Furthermore, when the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order of the organic compound layer 103 is reversed. Specifically, on the first electrode 101 which is the cathode, 111 is an electron injection layer, 112 is an electron transport layer, 113 is a light-emitting layer, 114 is a hole transport layer, and 115 is a hole injection layer.

[0119] The light-emitting layers 113 contained in the organic compound layers (103, 103a, 103b) each contain a light-emitting substance and a combination of multiple substances as appropriate, and can be configured to produce fluorescence emission or phosphorescence emission exhibiting a desired emission color. Alternatively, the light-emitting layers 113 may be arranged in a laminated structure with different emission colors. In this case, the light-emitting substance and other substances used in each laminated light-emitting layer may be made of different materials. Alternatively, a configuration may be used in which different emission colors can be obtained from multiple organic compound layers (103a, 103b) as shown in Figure 4B. In this case as well, the light-emitting substance and other substances used in each light-emitting layer may be made of different materials.

[0120] Furthermore, in a light-emitting device according to one aspect of the present invention, for example, by using a reflective electrode as the first electrode 101 shown in Figure 4C and a semi-transparent / semi-reflective electrode as the second electrode 102, and by using a microcavity structure, the light emitted from the light-emitting layer 113 contained in the organic compound layer 103 can be resonated between the two electrodes, thereby strengthening the light emitted from the second electrode 102. Therefore, it is easy to achieve high resolution. In addition, since it is possible to strengthen the light emission intensity in the front direction at a specific wavelength, power consumption can be reduced.

[0121] Furthermore, if the first electrode 101 of the light-emitting device is a reflective electrode consisting of a laminated structure of a reflective conductive material and a translucent conductive material (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust the optical distance (product of film thickness and refractive index) between the first electrode 101 and the second electrode 102 to be mλ / 2 (where m is an integer of 1 or more) or close to it, with respect to the wavelength λ of light obtained from the light-emitting layer 113.

[0122] 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 from which 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 from which the desired light is obtained (light-emitting region), so that they are (2m'+1)λ / 4 (where m' is an integer of 1 or more) or near that value. The light-emitting region referred to here is the region in the light-emitting layer 113 where holes and electrons recombine.

[0123] By performing such optical adjustments, the spectrum of specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, resulting in light emission with good color purity.

[0124] 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 is the reflective region. 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 the reflective region and any position on the light-emitting layer from which the desired light is obtained is the light-emitting region.

[0125] The light-emitting device shown in Figure 4D is a light-emitting device having a tandem structure. The tandem structure allows for a light-emitting device capable of high-brightness illumination. Furthermore, compared to a single structure, the tandem structure reduces the current required to achieve the same brightness, thereby improving reliability. It also reduces power consumption.

[0126] The light-emitting device shown in Figure 4E is an example of a tandem-structured light-emitting device shown in Figure 4B. As shown in the figure, it has a structure in which three organic compound layers (103a, 103b, 103c) are stacked with charge generation layers (106a, 106b) in between. Each of the three organic compound layers (103a, 103b, 103c) has a light-emitting layer (113a, 113b, 113c), and the light-emitting colors of each light-emitting layer can be freely combined. For example, light-emitting layer 113a can be blue, light-emitting layer 113b can be red, green, or yellow, and light-emitting layer 113c can be blue. Alternatively, light-emitting layer 113a can be red, light-emitting layer 113b can be blue, green, or yellow, and light-emitting layer 113c can be red.

[0127] In the light-emitting device according to one aspect of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (such as a transparent electrode or a semi-transparent / semi-reflective electrode). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. When it is a semi-transparent / semi-reflective electrode, the visible light reflectance of the semi-transparent / semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, these electrodes have a resistivity of 1 × 10⁻¹⁶. −２ It is preferable to keep it below Ωcm.

[0128] Furthermore, in the light-emitting device according to one aspect of the present invention described above, if one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. Also, the resistivity of this electrode is 1 × 10⁻¹⁶. −２ It is preferable to keep it below Ωcm.

[0129] <Specific Structure of the Light-Emitting Device> Next, a specific structure of a light-emitting device according to one aspect of the present invention will be described. Here, the explanation will be given using Figure 4D, which has a tandem structure. The same applies to the configuration of the organic compound layer for the single-structure light-emitting devices shown in Figures 4A and 4C. Furthermore, if the light-emitting device shown in Figure 4D has 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. Thus, one or more desired electrode materials can be used and formed in a single layer or in a stacked manner. The second electrode 102 is formed by selecting an appropriate material after the organic compound layer 103b has been formed.

[0130] <Materials for Light-Emitting Devices> <Light-Emitting Layers> The light-emitting layers (113, 113a, 113b) are layers containing a light-emitting material. The light-emitting material that can be used in the light-emitting layers (113, 113a, 113b) can be any material that exhibits a light-emitting color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red. Furthermore, if there are multiple light-emitting layers, a configuration exhibiting different light-emitting colors can be achieved by using different light-emitting materials in each layer (for example, white light emission obtained by combining complementary light-emitting colors). Additionally, a laminated structure in which one light-emitting layer contains a different light-emitting material is also possible.

[0131] Furthermore, the light-emitting layers (113, 113a, 113b) contain two or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0132] For example, the structure described with reference to Figure 1B can be used as the light-emitting layer 113. In the light-emitting layer 113, the host material 118 is present in the largest amount by weight, and the guest material 119 is dispersed in the host material 118. As the guest material 119, phosphorescent compounds or fluorescent compounds can be used. Mechanisms for efficiently emitting fluorescent compounds include TTA (triplet-triplet annealing) or TADF (thermally activated delayed fluorescent emission), and these mechanisms can be adopted as needed.

[0133] Next, a preferred configuration of the light-emitting layer 113 using a phosphorescent compound as the guest material 119 will be described.

[0134] In the light-emitting layer 113 using a phosphorescent compound as the guest material 119, the T of the host material 118 (organic compound 118_1 and organic compound 118_2) １ The energy level is the T of the guest material (guest material 119) of the light-emitting layer 113. １ It is preferable that the level be higher than the current level.

[0135] Furthermore, the lowest triplet excitation energy level (T １ The lowest triplet excitation energy level (T) can be calculated from the emission edge of the phosphorescence spectrum. Furthermore, compounds whose phosphorescence spectrum is not detectable at room temperature may be detectable by lowering the temperature (for example, any temperature in the range of 4K to 80K). The sample form when measuring the emission spectrum of the emission center material may be a thin film or a solution, but a solution is preferred from the viewpoint of verifying the state of isolated molecules. A solvent with relatively low polarity, such as toluene or chloroform, is preferred for the solution. Also, in the case of phosphorescent compounds used as emission center materials, the phosphorescence spectrum can be observed even at room temperature. Therefore, the lowest triplet excitation energy level (T) can be calculated. １ The temperature at which the energy level is measured can be low (for example, any temperature in the range of 4K to 80K) or room temperature (for example, 298K). The emission edge can be calculated by drawing a tangent line at the point where the slope on the short-wavelength side of the peak (or shoulder peak) observed at the shortest wavelength of the emission spectrum (phosphorescence spectrum) is maximum, and then taking the point where this tangent line intersects with the horizontal axis (wavelength) or baseline.

[0136] Furthermore, if no phosphorescent component is detected in the PL spectrum observed even at low temperatures in a thin film containing only the material to be measured, or in a solution to which only the material to be measured has been added, a phosphorescent sensitizer may be added. The phosphorescent sensitizer has a higher T than the material to be measured. １ Phosphorescent materials with energy levels can be used. Specifically, Ir(ppy)3 can be used.

[0137] Examples of materials that can be used as compounds exhibiting phosphorescence in the light-emitting layer 113 include the following. Other phosphorescent substances can also be used.

[0138] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazole-3-yl-κN2]phenyl-κC}Iridium(III) (Abbreviation: [Ir(mpptz-dmp) ３ ]), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato) iridium (III) (abbreviation: [Ir(Mptz) ３ ]) an organometallic iridium complex having a 4H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ３ ]), Tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato) Iridium(III) (abbreviation: [Ir(Prptz1-Me) ３ ]) an organometallic iridium complex having a 1H-triazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim) ３ ]), Tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridine]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ３ ]), organometallic iridium complexes having an imidazole skeleton such as tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazole-2-yl-κN3}-4-cyanophenyl-κC) iridium(III) (abbreviation: CNImIr), tris[(6-tert-butyl-3-phenyl-2H-imidazol[4,5-b]pyrazine-1-yl-κC2)phenyl-κC] iridium(III) (abbreviation: [Ir(cb) ３ Organometallic complexes having a benzimidazolidene skeleton such as ]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’Iridium(III) tetrakis(1 - pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C ２’} iridium(III) picolinate (abbreviation: [Ir(CF ３ ppy) ２ (pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’ iridium(III) acetylacetonate (abbreviation: FIr(acac)) and other organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand. These are compounds that exhibit blue phosphorescent emission and have an emission peak in the wavelength range from 440 nm to 520 nm.

[0139] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ３ ), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ３ ), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ２ (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ２ (acac)]), (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(mppppm) ２ (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ２Organometallic iridium complexes having a pyrimidine skeleton such as (acac) (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me) ２ (acac)), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ２ Organometallic iridium complexes having a pyrazine skeleton such as (acac), Tris(2-phenylpyridinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(ppy) ３ ]), bis(2-phenylpyridinate-N,C ２’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy) ２ (acac)), bis(benzo[h]quinolinate)iridium(III)acetylacetonate (abbreviation: [Ir(bzq) ２ (acac)), Tris(benzo[h]quinolinate) Iridium(III) (abbreviation: [Ir(bzq) ３ ]), Tris(2-phenylquinolinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(pq) ３ ]), bis(2-phenylquinolinato-N,C ２’ Iridium(III) acetylacetonate (abbreviation: [Ir(pq) ２ (acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3) ２ (mbfpypy-d3), {2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofl[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC}Iridium(III) (abbreviation: Ir(5mtpy-d6) ２(mbfpypy-iPr-d4)), [2-(methyl-d3)-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mbfpypy-d3)), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3) ２ (mdppy-d3)]), [2-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ２ (mbfpypy))]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ In addition to organometallic iridium complexes with a pyridine skeleton such as (mdppy), there is also tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ３ Examples include rare earth metal complexes such as (Phen)). These are compounds that mainly exhibit green phosphorescence and have emission peaks in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred because they exhibit outstanding reliability and luminescence efficiency.

[0140] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) ２ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ２ (dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm) ２Organometallic iridium complexes having a pyrimidine skeleton such as (dpm)]), (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: [Ir(tppr) ２ (acac)), bis(2,3,5-triphenylpyrazinate)(dipivaloylmethanato) iridium(III) (abbreviation: [Ir(tppr) ２ (dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ２ Organometallic iridium complexes having a pyrazine skeleton such as (acac), tris(1-phenylisoquinolinato-N,C) ２’ Iridium (III) (abbreviation: [Ir(piq) ３ ]), bis(1-phenylisoquinolinato-N,C ２’ Iridium (III) acetylacetonate (abbreviation: [Ir(piq) ２ (acac)), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl In addition to organometallic iridium complexes with a pyridine skeleton such as [-κC]iridium(III), there are platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), and tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)] ３ (Phen)]), Tris[1-(2-tenoyl)-3,3,3-trifluoroacetonate](monophenanthroline) europium(III) (abbreviation: [Eu(TTA) ３Examples include rare earth metal complexes such as (Phen)). These exhibit emission peaks in the wavelength range of 600 nm to 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton yield red emission with good chromaticity. Other known substances that exhibit red phosphorescence can also be used.

[0141] Furthermore, if the same light-emitting device contains light-emitting devices with different configurations, the light-emitting material may be a fluorescent material, a phosphorescent material, a material that exhibits thermally activated delayed fluorescence (TADF), or any other light-emitting material.

[0142] Next, we will describe a preferred configuration for the light-emitting layer 113 in which a fluorescent compound is used as the guest material 119, and in which the TADF mechanism is likely to occur.

[0143] TADF is S １ Level and T １ In systems with a very small difference between energy levels, a small amount of thermal energy can cause a reverse intersystem crossing from triplet excitation energy to singlet excitation energy, and fluorescence emission is generated from the converted singlet excitation energy. Therefore, it is possible to upconvert (reverse intersystem crossing) triplet excitation energy to singlet excitation energy, and singlet excited states can be efficiently generated. Furthermore, triplet excitation energy can be converted into luminescence. Materials exhibiting the TADF mechanism are sometimes called TADF materials.

[0144] The TADF mechanism may manifest with only one substance or with two substances. Note that the excited complex (also called an exciplex) formed by two substances is S １ Level and T １ It has an extremely small difference from the energy level and functions as a TADF material capable of converting triplet excitation energy into singlet excitation energy.

[0145] Note, - １ The level indicator can be calculated using the emission edge of the phosphorescence spectrum observed at low temperatures (for example, any temperature in the range of 4K to 80K). １As an indicator of the energy level, the emission edge of the PL spectrum measured at low temperature (e.g., any temperature in the range of 4K to 80K) or at room temperature can be used. Furthermore, the S of the fluorescent material... １ As an indicator of the energy level, an absorption spectrum measured at room temperature can also be used. For example, if an absorption spectrum is measured at room temperature, the energy at the absorption edge on the longer wavelength side can be defined as S. １ It can also be considered as an energy level. The absorption edge on the long-wavelength side of the absorption spectrum can be calculated by drawing a tangent line at the point where the slope on the long-wavelength side of the peak (or shoulder peak) observed at the longest wavelength of the absorption spectrum is minimum (maximum absolute value), and then taking the intersection of that tangent line with the horizontal axis (wavelength) or baseline. １ Level and T １ For comparing energy levels, it is particularly preferable to compare the emission edge of the fluorescence spectrum with the emission edge of the phosphorescence spectrum. １ Level and T １ The difference between the energy levels is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0146] Furthermore, when using TADF material as a light-emitting material, the S of the host material １ The level is S of the TADF material. １ A higher level is preferable. Also, the T of the host material １ The level is T of the TADF material. １ A level higher than the current level is preferable.

[0147] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc., can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can be used. As a metal-containing porphyrin, for example, the protoporphyrin-tin fluoride complex (SnF) shown in the following structural formula is used. ２ (Proto IX)), Mesoporphyrin-Tin Fluoride Complex (SnF ２ (Meso IX), hematoporphyrin-tin fluoride complex (SnF ２(Hemato IX), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ２ (Copro III-4Me)), Octaethylporphyrin-Tin Fluoride Complex (SnF ２ (OEP)), Ethioporphyrin-Tin Fluoride Complex (SnF ２ (Etio I)), Octaethylporphyrin-Platinum Chloride Complex (PtCl ２ OEP (Open Economic Programme) is another example.

[0148]

[0149] Furthermore, the following structural formulas represent 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTZn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzPTZn), and 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ). Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as -TRZ), 3-[4-(5-phenyl-5,10-dihydrophenadin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. Among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptability and are reliable. Furthermore, among the skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable, and therefore it is preferable to have at least one of these skeletons.Furthermore, a dibenzofuran skeleton is preferred as the furan skeleton, and a dibenzothiophene skeleton is preferred as the thiophene skeleton. In addition, an indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred as the pyrrole skeleton. Furthermore, in a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, both the electron-donating ability of the π-electron-rich heteroaromatic ring and the electron-accepting ability of the π-electron-deficient heteroaromatic ring are strengthened. １ Level and T １ This is particularly preferable because the energy difference between the levels becomes small, allowing for efficient acquisition of thermally activated delayed fluorescence. Alternatively, an aromatic ring to which an electron-withdrawing group such as a cyano group is attached may be used instead of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, etc., can be used as the π-electron-rich skeleton. Additionally, boron-containing skeletons such as xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, phenylborane or volanthrene skeletons, aromatic rings or heteroaromatic rings having a nitrile group or cyano group such as benzonitrile or cyanobenzene, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used as the π-electron-deficient skeleton and the π-electron-rich heteroaromatic ring. Thus, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used instead of at least one of the π-electron-deficient heteroaromatic ring and the π-electron-rich heteroaromatic ring.

[0150]

[0151] Furthermore, a TADF material may be used that enables extremely fast and reversible intersystem crossing, and in which the singlet and triplet excited states emit light according to a thermal equilibrium model. Such a TADF material has an extremely short emission lifetime (excitation lifetime) as a TADF material, and can suppress the decrease in efficiency in the high-brightness region of the light-emitting element. Specifically, materials with the molecular structure shown below can be used.

[0152]

[0153] Next, we will describe a preferred configuration for the light-emitting layer 113 in which a fluorescent compound is used as the guest material 119, and the TTA mechanism is generated.

[0154] In the case of a light-emitting device that uses a fluorescent material in the light-emitting layer and utilizes the TTA mechanism to increase luminescence efficiency, the lowest singlet energy level (S) of the host material is important. １ The level is the S of the fluorescent material. １ Higher than the level, and the lowest triplet energy level of the host material (T １ The T level of a fluorescent material is １ It is preferable that the level is lower than the host level. Furthermore, it is more preferable that the difference between the HOMO level of the host material and the HOMO level of the fluorescent material is 0.25 eV or more. In addition, it is preferable that the concentration of the fluorescent material in the light-emitting layer is 0.5 wt% to 25 wt% relative to the host material. With this configuration, holes are more easily trapped in the light-emitting layer, and carriers recombine locally in the region on the hole transport layer side of the light-emitting layer, increasing the exciton density and thus improving the efficiency of TTA. Another configuration that enhances the luminescence efficiency using TTA is that it is more preferable that the LUMO level of the fluorescent material is lower than the LUMO level of the host material. With this configuration, electrons are more easily trapped in the light-emitting layer, and carriers recombine locally in the region on the hole transport layer side of the light-emitting layer, increasing the exciton density and thus improving the efficiency of TTA.

[0155] The HOMO and LUMO levels used in this specification can be determined by electrochemical measurements. Typical examples of electrochemical measurements include square wave voltammetry (SWV), cyclic voltammetry (CV), and differential pulse voltammetry (DPV).

[0156] Specifically, in square wave voltammetry (SWV) measurements, the values ​​(E) of the HOMO and LUMO levels are obtained by changing the potential of the working electrode relative to the reference electrode. Oxidation peak potential (Ep ｏｘ ) and reduction peak potential (Ep ｒｅｄThe default current obtained in square wave voltammetry (SWV) measurement is used. In the measurement, the HOMO level is determined from the positive potential scan and the LUMO level is determined from the negative potential scan.

[0157] For example, the parameters for measurement can be set as follows: potential increase Incr E (V) = 0.004, amplitude Amplitude (V) = 0.025, and frequency Frequency (Hz) = 15. The scan speed in the measurement can be calculated by multiplying the potential increase (Incr E (V)) by 2πf (where f is the frequency). Specifically, under these parameter settings, 0.004 (V) × 2 × π × 15 (1 / s) = 0.3768 (V / s), and the scan speed is 0.38 (V / s).

[0158] Furthermore, the specific procedures for calculating the HOMO and LUMO levels will be explained. The oxidation peak potential (Ep) obtained from the rectangular wave voltammogram of the material is... ｏｘ ), or reduction peak potential (Ep ｒｅｄ ) is determined, and the potential energy (E) of the reference electrode with respect to the vacuum level is calculated. ｘ By subtracting from ), the HOMO level ((E) = Ex - Ep ｏｘ ), and the value of the LUMO level ((E) = Ex - Ep ｒｅｄ ) can be calculated for each of these.

[0159] Furthermore, in cyclic voltammetry (CV) measurements, the values ​​of the HOMO and LUMO levels (E) are obtained by changing the oxidation peak potential (E) relative to the reference electrode. ｐａ ), and reduction peak potential (E ｐｃ It can be calculated based on the following. In the measurement, the HOMO level is determined from the positive potential scan and the LUMO level is determined from the negative potential scan. The scan speed in the measurement is set to 0.1 V / s.

[0160] This section describes the specific procedure for calculating the HOMO and LUMO levels using CV measurements. The oxidation peak potential (E) obtained from the cyclic voltammogram of the material is then explained. ｐａ ), and reduction peak potential (E ｐｃ) From the standard oxidation-reduction potential (E ｏ ) (=(E ｐａ +E ｐｃ ) / 2) is calculated, and the potential energy (E) of the reference electrode with respect to the vacuum level is calculated. ｘ By subtracting from ), the values ​​(E) (= Ex - Eo) of the HOMO level and the LUMO level can be determined, respectively.

[0161] Note that the above shows the case where a reversible redox wave is obtained, but when an irreversible redox wave is obtained, the oxidation peak potential (E) is used to calculate the HOMO level. ｐａ The reduced peak potential (E) is obtained by subtracting a certain value (0.1 eV) from the value obtained by subtracting a certain value (0.1 eV) from the value obtained by subtracting a certain value (0.1 eV) from the value obtained by subtracting a certain value (E ｐｃ ) Assuming the standard oxidation-reduction potential (E ｏ ) is calculated to one decimal place. Also, the reduction peak potential (E) is used to calculate the LUMO level. ｐｃ The oxidation peak potential (E) is calculated by adding a constant value (0.1 eV) to the value obtained). ｐａ ) Assuming the standard oxidation-reduction potential (E ｏ Calculate the result to one decimal place.

[0162] Note S １ Levels and T １ The energy levels can be determined by using values ​​calculated from the emission edge of the phosphorescence or fluorescence spectrum and the absorption edge of the absorption spectrum, as described above.

[0163] Examples of materials that can be used as fluorescent light-emitting substances in the light-emitting layer 113 include the following. Other fluorescent light-emitting substances can also be used.

[0164] 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAPP2BPy), 5,6-bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl] )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA) 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyra N-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-diamine (abbreviation) Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naph Examples include to[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPPrn-03, are preferred because they exhibit high hole-trapping properties and excellent luminescence efficiency or reliability.

[0165] Also, 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazabolin-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazabolino[2,3,4-kl]phenazabolin-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-ter Materials having a diazabora-naphthanthracene skeleton, such as t-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazavolin (abbreviation: Me-tBu4DABNA) and N7,N7,N13,N13,5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazavolin-7,13-diamine (abbreviation: ν-DABNA), can be used.

[0166] Examples of electron transport materials used as the host material for the light-emitting layer 113 include bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq). ２Metal complexes such as bis(2-methyl-8-quinolinolato)(4-phenylphenololato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazollyl)phenololato]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenololato]zinc(II) (abbreviated as ZnBTZ), as well as organic compounds having a π-electron-deficient heteroaromatic ring, can be used. Examples of organic compounds having a π-electron-deficient heteroaromatic ring include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), and 1,3-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as Azole skeletons such as OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), and 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) Organic compounds containing heteroaromatic rings, such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPBQ-II), and 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2m CzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 2,4-bis[4-(1-naphthyl)phenyl]-6-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 6-(biphenyl-3-yl)-4-[3,Organic compounds containing heteroaromatic rings with a diazine skeleton, such as 5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), and 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), and 3,5-bis[3-(9 Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[(3-pyridyl)phenyl-3-yl]benzene (abbreviation: TmPyPB), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTZn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobio[9H-fluoren]-2-yl)-1,3,5-triazine Zin (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), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2, 1-b]carbazole (abbreviation: mINc(II)PTZn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTZn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTZn), 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,Examples include organic compounds containing heteroaromatic rings having a triazine skeleton, such as 5-triazine (abbreviated as mBP-TPDBfTZn). Among those mentioned above, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, and organic compounds containing heteroaromatic rings having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine and pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton exhibit high electron transport properties and contribute to reducing the driving voltage.

[0167] As the hole transport material used in the host material of the light-emitting layer 113, an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring can also be used. Examples of such organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), and 4-phenyl-4'-(9-phenylfluoren-9- 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)trif Phenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF) Compounds having an aromatic amine skeleton such as, 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), and other compounds having a carbazole skeleton, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, the organic compounds listed as examples of hole-transporting materials in the hole transport layer 112 can also be used as hole transport materials for the host.

[0168] Furthermore, by mixing electron transport material and hole transport material, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled.

[0169] Furthermore, TADF materials can also be used as electron transport materials or hole transport materials. The TADF materials listed above can be used as host materials in the same way. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted to singlet excitation energy through reverse intersystem crossing, and this energy is then transferred to the light-emitting material, thereby increasing the luminescence efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0170] This is very effective when the above-mentioned luminescent material is a fluorescent luminescent material. Also, in order to obtain high luminescence efficiency in this case, the S of the TADF material １ The energy level is S of the fluorescent material. １ It is preferable that the level be higher than the level. Also, the T of the TADF material １ The energy level is S of the fluorescent material.１ It is preferable that the level be higher than the level of the TADF material. １ The energy level is the T of the fluorescent material. １ A level higher than the current level is preferable.

[0171] Furthermore, it is preferable to use a TADF material that exhibits emission that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows for a smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0172] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To achieve this, it is preferable that the fluorescent material has protecting groups around the luminescent phosphoform (the skeleton that causes luminescence). Preferred protecting groups are substituents without π bonds, and saturated hydrocarbons are preferred. Specifically, examples include alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable to have multiple protecting groups. Substituents without π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphoform of the fluorescent material with little effect on carrier transport and carrier recombination. Here, the luminescent phosphoform refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminescent phosphophore preferably has a skeleton containing π bonds, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such luminescent phosphophores include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, phenothiazine skeletons, naphthalene skeletons, anthracene skeletons, fluorene skeletons, chrysene skeletons, triphenylene skeletons, tetracene skeletons, pyrene skeletons, perylene skeletons, coumarin skeletons, quinacridone skeletons, and naphthobisbenzofuran skeletons. Fluorescent materials having naphthalene, anthracene, fluorene, chrysene, triphenylene, tetracene, pyrene, perylene, coumarin, quinacridone, and naphthobisbenzofuran skeletons are particularly preferred due to their high fluorescence quantum yield.

[0173] Furthermore, when a fluorescent material is used as the light-emitting material in the light-emitting layer 113, it is more preferable to use a condensed polycyclic aromatic compound such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, or dibenzo[g,p]chrysene derivatives as the host material, which is an organic compound with a large singlet excited state energy level and a small triplet excited state energy level. Materials having an anthracene skeleton are particularly preferred. When a substance having an anthracene skeleton is used as the host material for the fluorescent material, it is possible to realize a light-emitting layer with good luminescence efficiency and durability. As a substance having an anthracene skeleton to be used as the host material, a diphenylanthracene skeleton, and especially a substance having a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Examples of such substances include organic compounds having heteroaromatic rings and aromatic compounds consisting of aromatic hydrocarbons. Examples of organic compounds containing heteroaromatic rings include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), and 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA). Examples include 2-(10-phenyl-9-anthryl)benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA), 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA), 1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA-02-d5), and 7-(phenyl-2,3,4,5,6-d5)-1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]dibenzofuran (abbreviated as PDBfPhA-d10).Examples of aromatic compounds consisting of aromatic hydrocarbons include 9-phenyl-10-[4'-(9-phenyl-9H-fluoren-9-yl)biphenyl-4-yl]anthracene (abbreviated as FLPPA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviated as α,βADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviated as βN-mβNPAnth), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth), and 2,9-di(1-naphthyl)-10-phenylanthracene (abbreviated as 2αN-αNPhA). The light hydrogen atoms in these organic compounds having heteroaromatic rings and aromatic compounds consisting of aromatic hydrocarbons may each be independently deuterium.

[0174] Specifically, as organic compounds having the heteroaromatic ring described above, organic compounds represented by structural formulas (100) to (118) can be used in a light-emitting device according to one aspect of the present invention.

[0175]

[0176]

[0177] The organic compounds represented by structural formulas (100) to (118) above are examples of organic compounds having a heteroaromatic ring, and the organic compounds used in the light-emitting device according to one embodiment of the present invention are not limited thereto.

[0178] Furthermore, specifically, as aromatic compounds consisting of the above-mentioned aromatic hydrocarbons, organic compounds represented by structural formulas (200) to (232) can be used in a light-emitting device according to one aspect of the present invention.

[0179]

[0180]

[0181]

[0182] The organic compounds represented by structural formulas (200) to (232) above are examples of organic compounds having heteroaromatic rings, and the organic compounds used in the light-emitting device according to one aspect of the present invention are not limited thereto.

[0183] Furthermore, phosphorescent materials can be used as part of the above-mentioned mixed materials. When a fluorescent material is used as the light-emitting material, the phosphorescent material can be used as an energy donor to supply excitation energy to the fluorescent material.

[0184] Furthermore, an excited complex may be formed between the mixed materials described above. It is preferable to select a combination of materials that forms an excited complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the luminescent material, as this facilitates smooth energy transfer and efficiently obtains light emission. This configuration is also preferable because it reduces the driving voltage.

[0185] Furthermore, at least one of the materials forming the excitation complex may be a phosphorescent material. This allows for the efficient conversion of the triplet excitation energy to the singlet excitation energy through reverse intersystem crossing.

[0186] For efficient excitation complex formation, it is preferable that the HOMO level of the hole-transporting material is at or above the HOMO level of the electron-transporting material. Furthermore, it is preferable that the LUMO level of the hole-transporting material is at or above the LUMO level of the electron-transporting material.

[0187] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above may be read as transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0188] The light-emitting layer 113 can be formed by methods other than the light-emitting mechanism, such as vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing. In addition to the materials mentioned above, it may also contain inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.).

[0189] ≪Hole Injection Layer≫ The hole injection layer (111, 111a, 111b) is a layer that injects holes from the first electrode 101, which is the anode, and the charge generation layer (106, 106a, 106b) into the organic compound layer (103, 103a, 103b), and is a layer that contains an organic acceptor material and a material with high hole injection potential.

[0190] The hole injection layers (111, 111a, 111b) can be compounds having electron-withdrawing groups (halogen groups or cyano groups), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ４Examples include HAT-CN, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and therefore preferred. Furthermore, [3]radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups or cyano groups) are preferred because they have very high electron-accepting properties. Specifically, examples include α,α',α''-1,2,3-cyclopropanetriylidenates [4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates [2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates [2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds mentioned above, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. can be used as substances with acceptor properties. Other examples include phthalocyanine (abbreviation: H ２ Hole injection layers (111, 111a, 111b) can also be formed by phthalocyanine compounds such as Pc, phthalocyanine complex compounds such as copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS). Accepting substances can extract electrons from adjacent hole transport layers (or hole transport materials) by applying an electric field.

[0191] Furthermore, among substances with acceptor properties, organic compounds with acceptor properties are easy to use because they are readily deposited and easy to form films.

[0192] Furthermore, a composite material containing the above-mentioned acceptor substance in a hole-transporting material can also be used as the hole injection layer (111, 111a, 111b). By using a composite material containing the acceptor substance in a hole-transporting material, it is possible to select the material for forming the electrode regardless of the work function. In other words, not only materials with a large work function but also materials with a small work function can be used as the anode (first electrode 101).

[0193] Various organic compounds can be used as hole-transporting materials in composite materials, including aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.). −６ cm ２ It is preferable that the material has a hole mobility of 1 / Vs or higher. Below, we specifically list organic compounds that can be used as hole transporting materials in composite materials.

[0194] Aromatic amine compounds that can be used in composite materials include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B). Specifically, carbazole derivatives include 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenyl Carbazole (abbreviated as PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole (abbreviated as CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert- Examples include butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-biantryl, 10,10'-diphenyl-9,9'-biantryl, 10,10'-bis(2-phenylphenyl)-9,9'-biantryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-biantryl, anthracene, tetracene, rubrene, perylene, and 2,5,8,11-tetra(tert-butyl)perylene. In addition, pentacene, coronene, and the like can also be used. Furthermore, it may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviated as DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviated as DPVPA). Organic compounds according to one embodiment of the present invention can also be used.

[0195] In addition, polymer compounds such as 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) can also be used.

[0196] The hole-transporting material used in the composite material more preferably has at least one of the following skeletons: carbazole, dibenzofuran, dibenzothiophene, and anthracene. In particular, it 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 of the amine via an arylene group. Furthermore, it is preferable that these organic compounds are substances having an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime. Specifically, the organic compounds described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BBABnf), and 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl). )-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(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: BB AβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-([2,1'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-([2,2'-binaphthyl]-6-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-([2,2'-binaphthyl]-7-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-([1,2'-binaphthyl]-4-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-( [1,2'-binaphthyl]-5-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl Triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyl Triphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluoren]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9 H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine Examples include PCBiF (abbreviation: PCBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-2-amine, and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-1-amine.

[0197] Furthermore, it is even more preferable that the hole-transporting material used in the composite material has a relatively low HOMO level between -5.7 eV and -5.4 eV. Having a relatively low HOMO level in the hole-transporting material used in the composite material facilitates the injection of holes into the hole transport layer 112 and makes it easier to obtain a light-emitting device with a good lifetime. In addition, having a relatively low HOMO level in the hole-transporting material used in the composite material moderately suppresses hole induction, resulting in a light-emitting device with an even better lifetime.

[0198] Furthermore, by mixing alkali metal or alkaline earth metal fluoride into the above composite material (preferably with an atomic ratio of fluorine atoms of 20% or more in the layer), the refractive index of the layer can be reduced. This also makes it possible to form a layer with a low refractive index inside the EL layer 103, thereby improving the external quantum efficiency of the light-emitting device.

[0199] By forming hole injection layers (111, 111a, 111b), hole injection performance is improved, and a light-emitting device with a low driving voltage can be obtained.

[0200] ≪Hole Transport Layer≫ The hole transport layer (112, 112a, 112b) is a layer containing a hole transport material, and the hole transport material exemplified as the material for the hole injection layer (111, 111a, 111b) can be used. Since the hole transport layer (112, 112a, 112b) has the function of transporting holes injected into the hole injection layer (111, 111a, 111b) to the light-emitting layer (113, 113a, 113b), it is preferable that it has the same or close HOMO level as the HOMO level of the hole injection layer (111, 111a, 111b).

[0201] Also, 1 x 10 −６ cm ２ It is preferable that the material has a hole mobility of 1 / Vs or higher. However, other materials may be used as long as they have higher hole transport capabilities than electron transport capabilities. The layer containing the material with high hole transport capabilities may be a single layer, or two or more layers made of the above material may be stacked.

[0202] Materials that can be used for the hole transport layer (112, 112a, 112b) include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BP AFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4 Compounds having an aromatic amine skeleton such as ''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4, 4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,Compounds having a carbazole skeleton such as 3'-bicarbazole (abbreviation: mBPCCP), 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) Examples include compounds having a thiophene skeleton such as phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, the materials listed as having hole transportability used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112.

[0203] ≪Electron Transport Layer≫ The electron transport layers (114, 114a, 114b) have the function of transporting electrons injected from the other electrode of the pair (first electrode 101 or second electrode 102) to the light-emitting layer 113 via the electron injection layers (115, 115a, 115b).

[0204] Furthermore, as an electron-transporting material, it is an organic compound having electron-transporting properties, and the electron mobility at which the square root of the electric field strength [V / cm] is 600 is 1 × 10⁻⁶. −６ cm ２A substance having an electron mobility of 1 / Vs or higher is preferred. However, any substance that has higher electron transport than holes can be used. As the above organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As an organic compound having a π-electron-deficient heteroaromatic ring, it is preferable that it be any or more of the following: an organic compound containing a heteroaromatic ring having an azole skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, an organic compound containing a heteroaromatic ring having a diazine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton.

[0205] Organic compounds having a π-electron-deficient heteroaromatic ring that can be used in the above electron transport layer include, specifically, 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 1,3-bis[5-(4-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), and 9-[4-(5-phenyl-1,3,4-o Organic compounds having an azole skeleton, such as xadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviation: BzOs), and 3,5-bis[3-(9H-carbazole-9-yl) Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as [phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[(3-pyridyl)phenyl-3-yl]benzene (abbreviation: TmPyPB), vasophenanthroline (abbreviation: Bphen), vasocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3 '-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,[h]Quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]Quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]Quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl -4-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9 H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzoflo[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 8-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfp m), 8-([2,2'-binaphthalene]-6-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofl[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-Bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,4-Bis[4-(1-naphthyl)phenyl]-6-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]cal Organic compounds having a diazine skeleton, such as Bazole (abbreviation: PC-cgDBCzQz), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTZn), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobio[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTZn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1 ,3,5-triazine (abbreviation: mBnfBPTZn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTZn-02), 9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzPTZn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTZn-02), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTZn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTZn), 2,4,6-tris[3'-(pyridine-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTZn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindoro[2,3-a]carbazole (abbreviation: BP-Icz(II)TZn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3 Examples of organic compounds having a triazine skeleton include 5-triazine (abbreviated as mTpBPTZn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTZn), and 2-(biphenyl-3-yl)-4-phenyl-6-[8-([1,1':4',1''-terphenyl]-4-yl)-1-dibenzofuranyl]-1,3,5-triazine (abbreviated as mBP-TPDBfTZn). Among the above, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred due to their good reliability. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine and pyrazine) skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton, exhibit high electron transport properties and contribute to reducing the driving voltage.

[0206] Furthermore, the electron transport layers (114, 114a, 114b) may be not only a single layer, but also two or more layers made of the above material stacked together.

[0207] Furthermore, a layer for controlling the movement of electron carriers may be provided between the electron transport layers (114, 114a, 114b) and the light-emitting layers (113, 113a, 113b). This layer is made by adding a small amount of a substance with high electron-trapping properties to the electron-transporting material described above, and by suppressing the movement of electron carriers, it is possible to adjust the carrier balance. Such a configuration is highly effective in suppressing problems that occur when electrons penetrate the light-emitting layer (for example, a decrease in device lifespan).

[0208] ≪Electron injection layer≫ The electron injection layer (115, 115a, 115b) has the function of promoting electron injection by reducing the electron injection barrier from the second electrode 102.

[0209] Furthermore, for example, Group 1 metals, Group 2 metals, or their oxides, halides, carbonates, etc., can be used. Also, composite materials of the electron-transporting material and an electron-donating material can be used. Examples of electron-donating materials include Group 1 metals, Group 2 metals, or their oxides. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF) ２ ), lithium oxide (LiO ｘ Alkali metals, alkaline earth metals, or compounds thereof, such as ) can be used. Also, erbium fluoride (ErF) can be used. ３ Rare earth metal compounds such as ) can be used. Alternatively, an electride may be used in the electron injection layer 115. Examples of such electrides include a substance obtained by adding electrons to a mixed oxide of calcium and aluminum at a high concentration. Furthermore, the electron injection layers (115, 115a, 115b) may be made of a substance that can be used in the electron transport layers (114, 114a, 114b).

[0210] Furthermore, a composite material obtained by mixing an organic compound and an electron donor may be used in the electron injection layers (115, 115a, 115b). Such a composite material has 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, and specifically, for example, the substance that constitutes the electron transport layer 114 described above (metal complex, or heteroaromatic compound, etc.) can be used. As the electron donor, any substance that exhibits electron-donating properties to the organic compound is acceptable. Specifically, alkali metals, alkaline earth metals, or rare earth metals are preferred, such as lithium, sodium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides or 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. Furthermore, organic compounds such as tetrathiafulvalene (abbreviated as TTF) can also be used.

[0211] The light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer described above can be formed by methods such as vapor deposition (including vacuum deposition), inkjet printing, coating, and gravure printing, respectively. In addition to the materials described above, inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.) may also be used for the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer.

[0212] Furthermore, the quantum dots may include colloidal quantum dots, alloy quantum dots, core-shell quantum dots, core quantum dots, etc. Quantum dots containing elemental groups from groups 2 and 16, 13 and 15, 13 and 17, 11 and 17, or 14 and 15 may also be used. Alternatively, quantum dots containing elements such as cadmium (Cd), selenium (Se), zinc (Zn), sulfur (S), phosphorus (P), indium (In), tellurium (Te), lead (Pb), gallium (Ga), arsenic (As), and aluminum (Al) may be used.

[0213] <Pair of electrodes> The first electrode 101 and the second electrode 102 function as the anode or cathode of the light-emitting device. The first electrode 101 and the second electrode 102 can be formed using metals, alloys, conductive compounds, mixtures thereof, or laminates.

[0214] Preferably, one of the first electrode 101 or the second electrode 102 is formed of a conductive material having the function of reflecting light. Examples of such conductive materials include aluminum (Al) or alloys containing Al. Examples of alloys containing Al include alloys containing Al and L (where L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)), such as alloys containing Al and Ti, or Al, Ni, and La. Aluminum has low resistance and high light reflectivity. In addition, since aluminum is abundant in the Earth's crust and inexpensive, using aluminum can reduce the manufacturing cost of light-emitting devices. In addition, alloys containing silver (Ag), or Ag and N (where N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir), or gold (Au) may be used. Examples of silver-containing alloys include alloys containing silver, palladium, and copper; alloys containing silver and copper; alloys containing silver and magnesium; alloys containing silver and nickel; alloys containing silver and gold; and alloys containing silver and ytterbium. Other transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium can also be used.

[0215] Furthermore, the light emitted from the light-emitting layer is extracted through one or both of the first electrode 101 and the second electrode 102. Therefore, it is preferable that at least one of the first electrode 101 and the second electrode 102 be made of a conductive material that has the function of transmitting light. The conductive material has a visible light transmittance of 40% to 100%, preferably 60% to 100%, and a resistivity of 1 × 10⁻¹⁶.−２ Examples of conductive materials include those with a conductivity of Ω·cm or less.

[0216] Furthermore, the first electrode 101 and the second electrode 102 may be formed from a conductive material having the function of transmitting light and the function of reflecting light. The conductive material has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1 × 10⁻⁶. −２ Examples of conductive materials include those with a conductivity of Ω·cm or less. For example, they can be formed using one or more types of conductive metals, alloys, or conductive compounds. Specifically, for example, metal oxides such as indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide (abbreviated as ITSO), indium zinc oxide, indium tin oxide containing titanium, indium titanium oxide, and indium oxide containing tungsten and zinc oxide can be used. In addition, a thin metal film that transmits light (preferably with a thickness of 1 nm to 30 nm) can be used. As a metal, for example, Ag can be used. As an alloy, alloys such as Ag and Al, Ag and Mg, Ag and Au, Ag and Yb can be used.

[0217] In this specification, a material having the function of transmitting light is any material that has the function of transmitting visible light and is conductive, and may include, for example, oxide conductors represented by ITO as described above, oxide semiconductors, or organic conductors containing organic matter. Examples of organic conductors containing organic matter include composite materials obtained by mixing an organic compound with an electron donor, and composite materials obtained by mixing an organic compound with an electron acceptor. Inorganic carbon-based materials such as graphene may also be used. The resistivity of the material is preferably 1 × 10⁻⁶. ５ Ω·cm or less, more preferably 1 × 10⁻⁶ ４ It is less than or equal to Ω·cm.

[0218] Alternatively, one or both of the first electrode 101 and the second electrode 102 may be formed by stacking multiple of the above materials.

[0219] Furthermore, to improve light extraction efficiency, a material with a higher refractive index than the electrode may be formed in contact with an electrode that has the function of transmitting light. Such a material can be any material that has the function of transmitting visible light, and may or may not be conductive. For example, in addition to the oxide conductors mentioned above, oxide semiconductors and organic materials can be used. Examples of organic materials include the materials exemplified in the light-emitting layer, hole injection layer, hole transport layer, electron transport layer, or electron injection layer. Inorganic carbon-based materials or thin metal films that transmit light to a certain extent can also be used, and multiple layers of several nanometers to tens of nanometers may be stacked.

[0220] When the first electrode 101 or the second electrode 102 functions as a cathode, it is preferable to use a material with a small work function (3.8 eV or less). For example, elements belonging to Group 1 or Group 2 of the periodic table (alkali metals such as lithium, sodium, and cesium; alkaline earth metals such as calcium and strontium; magnesium, etc.), alloys containing these elements (e.g., Ag and Mg, Al and Li), rare earth metals such as europium (Eu) and Yb, alloys containing these rare earth metals, alloys containing aluminum and silver, etc. can be used.

[0221] Furthermore, when using the first electrode 101 or the second electrode 102 as an anode, it is preferable to use a material with a large work function (4.0 eV or more).

[0222] Furthermore, the first electrode 101 and the second electrode 102 may be laminates of a conductive material having the function of reflecting light and a conductive material having the function of transmitting light. In that case, the first electrode 101 and the second electrode 102 are preferable because they can have a function of adjusting the optical distance so that they can resonate with the desired light from each light-emitting layer and intensify the light of that wavelength.

[0223] The first electrode 101 and the second electrode 102 can be formed using methods such as sputtering, vapor deposition, printing, coating, MBE (Molecular Beam Epitaxy), CVD, pulsed laser deposition, ALD (Atomic Layer Deposition), etc., as appropriate.

[0224] ≪Charge Generation Layer (Intermediate Layer)≫ The charge generation layer 106 has the function of injecting electrons into the organic compound layer 103a and holes into the organic compound layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layer 106 may be a configuration in which an electron acceptor is added to a hole transport material (also called a p-type layer), or a configuration in which an electron donor is added to an electron transport material (also called an electron injection buffer layer). Furthermore, both of these configurations may be laminated. In addition, an electron relay layer may be provided between the p-type layer and the electron injection buffer layer. By forming the charge generation layer 106 using the materials described above, it is possible to suppress the increase in driving voltage when an organic compound layer including an emissive layer is laminated.

[0225] In the charge generation layer 106, when an electron acceptor is added to a hole-transporting material which is an organic compound (p-type layer), the hole-transporting material shown in this embodiment can be used. Furthermore, as the electron acceptor, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F) can be used. ４ Examples include -TCNQ, chloranil, etc. Also, oxides of metals belonging to groups 4 through 8 of the periodic table can be used. Specifically, examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. The above-mentioned acceptor materials may also be used. Furthermore, the materials constituting the p-type layer may be used as a mixed film, or single films containing each material may be laminated.

[0226] Furthermore, in the charge generation layer 106, if an electron donor is added to the electron transport material (electron injection buffer layer), the electron transport material may be the electron transport material shown in this embodiment.

[0227] Furthermore, alkali metals, alkaline earth metals, rare earth metals, or metals belonging to groups 2 and 13 of the periodic table, as well as their oxides and carbonates, can be used as electron donors. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (Li) ２ It is preferable to use o), cesium carbonate, etc. Alternatively, an organic compound such as tetrathianaphthalene may be used as an electron donor.

[0228] In the charge generation layer 106, when an electron relay layer is provided between the p-type layer and the electron injection buffer layer, the electron relay layer contains at least an electron-transporting material and has the function of preventing interaction between the electron injection buffer layer and the p-type layer and smoothly transferring electrons. Preferably, the LUMO level of the electron-transporting material included in the electron relay layer is between the LUMO level of the acceptor material in the p-type layer and the LUMO level of the electron-transporting material included in the electron transport layer in contact with the charge generation layer 106. The specific energy level of the LUMO level of the electron-transporting material used in the electron relay layer is preferably -5.0 eV or higher, more preferably -5.0 eV or higher and -3.0 eV or lower. Preferably, as the electron-transporting material used in the electron relay layer, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is used.

[0229] Although Figure 4D shows a configuration in which two organic compound layers 103 are stacked, a stacked structure of organic compound layers containing three or more light-emitting layers may be used by providing a charge generation layer between different light-emitting layers.

[0230] <<Cap Layer>> Although not shown in Figures 4A to 4E, a cap layer may be provided on the second electrode 102 of the light-emitting device. For example, a material with a high refractive index can be used for the cap layer. By providing a cap layer on the second electrode 102, the extraction efficiency of the light emitted from the second electrode 102 can be improved.

[0231] Specific examples of materials that can be used in the cap layer include 5,5'-diphenyl-2,2'-di-5H-[1]benzothieno[3,2-c]carbazole (abbreviated as BisBTc) and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II).

[0232] <Substrate> Furthermore, a light-emitting device according to one aspect of the present invention may be manufactured on a substrate made of glass, plastic, or the like. The order in which the components are manufactured on the substrate may be either by stacking them sequentially from the first electrode 101 side, or by stacking them sequentially from the second electrode 102 side.

[0233] In addition, as a substrate on which a light-emitting device according to one aspect of the present invention can be formed, for example, glass, quartz, or plastic can be used. A flexible substrate may also be used. A flexible substrate is a substrate that can be bent (flexible), and examples include plastic substrates made of polycarbonate or polyarylate. Films, inorganic vapor-deposited films, etc., can also be used. In addition, other materials are acceptable as long as they function as a support in the manufacturing process of the light-emitting device and optical element. Alternatively, any material that has the function of protecting the light-emitting device and optical element is acceptable.

[0234] For example, in this specification, light-emitting devices can be formed using various substrates. The type of substrate is not particularly limited. Examples of substrates include semiconductor substrates (e.g., single-crystal substrates such as silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, substrates with stainless steel foil, tungsten substrates, substrates with tungsten foil, flexible substrates, laminated films, cellulose nanofibers (CNF) containing fibrous materials, paper, or base films. Examples of glass substrates include barium borosilicate glass, aluminobosilicate glass, or soda-lime glass. Examples of flexible substrates, laminated films, and base films include the following: For example, plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE). Alternatively, as an example, acrylic resin. Alternatively, as an example, polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride. Alternatively, examples include resins such as polyamide, polyimide, aramid, or epoxy, inorganic vapor-deposited films, or papers.

[0235] Alternatively, a flexible substrate may be used as the substrate, and the light-emitting device may be formed directly on the flexible substrate. Or, a release layer may be provided between the substrate and the light-emitting device. The release layer can be used to separate the light-emitting device from the substrate after it has been partially or completely completed on it, and to transfer it to another substrate. In this case, the light-emitting device can be transferred to a substrate with poor heat resistance or a flexible substrate. The release layer can be configured in various ways, such as a laminated inorganic film structure of a tungsten film and a silicon oxide film, or a resin film such as polyimide formed on the substrate.

[0236] In other words, a light-emitting device may be formed using one substrate, then the light-emitting device may be transferred to another substrate, and the light-emitting device may be placed on the other substrate. Examples of substrates to which the light-emitting device is transferred include, in addition to the substrates mentioned above, cellophane substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester), or recycled fibers (acetate, cupro, rayon, recycled polyester), etc.), leather substrates, or rubber substrates. By using these substrates, it is possible to create light-emitting devices that are less prone to breakage, have high heat resistance, are lightweight, or are thin.

[0237] Alternatively, a field-effect transistor (FET), for example, may be formed on the aforementioned substrate, and a light-emitting device may be fabricated on an electrode electrically connected to the FET. This makes it possible to fabricate an active-matrix type display device in which the driving of the light-emitting device is controlled by the FET.

[0238] In this embodiment, one aspect of the present invention has been described. Alternatively, in other embodiments, one aspect of the present invention may be described. However, the aspects of the present invention are not limited to these. In other words, since various aspects of the invention are described in this embodiment and other embodiments, the aspects of the present invention are not limited to a specific aspect. For example, an example of application to a light-emitting device has been shown as one aspect of the present invention, but the aspects of the present invention are not limited to this. For example, depending on the circumstances, one aspect of the present invention may not be applied to a light-emitting device.

[0239] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0240] (Embodiment 2) The light-emitting device 130 constitutes a display device formed in multiple locations on the insulating layer 175, as illustrated in Figures 5A and 5B. In this embodiment, a display device according to one aspect of the present invention will be described in detail.

[0241] The display device 100 has a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixels 178 include sub-pixels 110R, sub-pixels 110G, and sub-pixels 110B.

[0242] In this specification, when describing matters common to, for example, sub-pixels 110R, 110G, and 110B, they may be referred to simply as sub-pixel 110. Similarly, when describing matters common to other components distinguished by letters, the letters may be omitted and the corresponding symbols used.

[0243] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. This allows an image to be displayed on the pixel section 177. In this embodiment, three sub-pixels of red (R), green (G), and blue (B) are used as an example, but combinations of other colors of sub-pixels may also be used. Furthermore, the number of sub-pixels is not limited to three, but may be four or more. Examples of four sub-pixels include four sub-pixels of R, G, B, and white (W), four sub-pixels of R, G, B, and yellow (Y), and four sub-pixels of R, G, B, and infrared (IR).

[0244] In this specification and other documents, the row direction may be referred to as the X direction and the column direction as the Y direction. The X and Y directions intersect, for example, perpendicularly.

[0245] Figure 5A shows an example where subpixels of different colors are arranged in the X direction, and subpixels of the same color are arranged in the Y direction. Alternatively, subpixels of different colors may be arranged in the Y direction, and subpixels of the same color may be arranged in the X direction.

[0246] A connecting portion 140 and a region 141 may be provided on the outside of the pixel portion 177. The region 141 is provided between the pixel portion 177 and the connecting portion 140. An organic compound layer 103 is provided in the region 141. A conductive layer 151C is provided in the connecting portion 140.

[0247] Figure 5 shows an example where region 141 and connection portion 140 are located to the right of the pixel portion 177, but the positions of region 141 and connection portion 140 are not particularly limited. Also, region 141 and connection portion 140 may be singular or multiple.

[0248] Figure 5B is an example of a cross-sectional view between the dashed line A1 and A2 in Figure 5A. As shown in Figure 5A, the display device 100 has an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). The insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach the conductive layer 172, and plugs 176 are provided to fill these openings.

[0249] In the pixel section 177, a light-emitting device 130 is provided on an insulating layer 175 and a plug 176. A protective layer 131 is provided so as to cover the light-emitting device 130. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Preferably, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0250] In Figure 5B, multiple cross-sections of the inorganic insulating layer 125 and the insulating layer 127 are shown, but when the display device 100 is viewed from above, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are connected as one unit. In other words, it is preferable that the insulating layer 127 is an insulating layer having an opening on the first electrode.

[0251] In Figure 5B, the light-emitting device 130 is shown as light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B. Light-emitting devices 130R, 130G, and 130B emit different colors from each other. For example, light-emitting device 130R can emit red light, light-emitting device 130G can emit green light, and light-emitting device 130B can emit blue light. In addition, light-emitting devices 130R, 130G, or 130B may emit other visible light or infrared light.

[0252] One embodiment of the present invention can be a top-emission type, for example, which emits light in the opposite direction to the substrate on which the light-emitting device is formed. Alternatively, one embodiment of the present invention may be a bottom-emission type.

[0253] Examples of light-emitting materials in the light-emitting device 130 include organic compounds or organometallic complexes such as fluorescent substances (fluorescent compounds), phosphorescent substances (phosphorescent compounds), and thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). Inorganic compounds such as quantum dots may also be used.

[0254] The light-emitting device 130R has the configuration shown in Figure 1A. It includes a first electrode (pixel electrode) consisting of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103R during processing. If the common layer 104 is provided, it is preferable that the common layer 104 is an electron injection layer. Furthermore, if the common layer 104 is provided, the laminated structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 1.

[0255] The light-emitting device 130G has the configuration shown in Figure 1A. It includes a first electrode (pixel electrode) consisting of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103G during processing. If the common layer 104 is provided, it is preferable that the common layer 104 is an electron injection layer. Furthermore, if the common layer 104 is provided, the laminated structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 1.

[0256] The light-emitting device 130B has the configuration shown in Figure 1A. It includes a first electrode (pixel electrode) consisting of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but its provision is preferable because it reduces damage to the organic compound layer 103B during processing. If the common layer 104 is provided, it is preferable that the common layer 104 is an electron injection layer. Furthermore, if the common layer 104 is provided, the laminated structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 1.

[0257] Of the pixel electrodes and common electrodes in a light-emitting device, one functions as the anode and the other as the cathode. In the following explanation, unless otherwise specified, it is assumed that the pixel electrodes function as the anode and the common electrodes function as the cathode.

[0258] The organic compound layers 103R, 103G, and 103B are independently arranged in island-like formations for each sub-pixel or each light-emitting color. By providing the organic compound layer 103 in island-like formations for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in high-definition display devices. This prevents crosstalk and enables the realization of a display device with extremely high contrast. In particular, it enables the realization of a display device with high current efficiency at low brightness.

[0259] The island-shaped organic compound layer 103 is formed by depositing an EL film and processing the EL film using a lithography method.

[0260] Furthermore, in a display device according to one aspect of the present invention, it is preferable that the first electrode (pixel electrode) of the light-emitting device be in a stacked configuration. For example, in the example shown in Figure 5B, the first electrode of the light-emitting device 130 is in a stacked configuration of a conductive layer 151 and a conductive layer 152. For example, when the display device 100 is a top-emission type and the pixel electrode of the light-emitting device 130 functions as an anode, it is preferable that the conductive layer 151 is a layer with high reflectivity for visible light, and the conductive layer 152 is a layer that, for example, transmits visible light and has a large work function. When the display device 100 is a top-emission type, the higher the reflectivity of the pixel electrode for visible light, the higher the efficiency of extracting light emitted by the organic compound layer 103. Also, when the pixel electrode functions as an anode, the larger the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. Based on the above, by making the pixel electrodes of the light-emitting device 130 a stacked structure consisting of a conductive layer 151 with high reflectivity for visible light and a conductive layer 152 with a large work function, the light-emitting device 130 can be made into a light-emitting device with high light extraction efficiency and low driving voltage.

[0261] When the conductive layer 151 is a layer with high reflectivity to visible light, it is preferable that the reflectivity of the conductive layer 151 to visible light be, for example, 40% to 100% or 70% to 100%. Furthermore, when the conductive layer 152 is an electrode that transmits visible light, it is preferable that its transmittance to visible light be, for example, 40% or more.

[0262] In cases where the pixel electrode has a stacked structure consisting of multiple layers, the pixel electrode may be altered due to reactions between these layers, for example. For instance, when a film formed after the pixel electrode is created is removed by a wet etching method, galvanic corrosion may occur when the chemical solution comes into contact with the pixel electrode.

[0263] Therefore, in the display device 100 of this embodiment, an insulating layer 156 is formed on the side surfaces of the conductive layer 151 and the conductive layer 152. This makes it possible to suppress contact of the chemical solution with the conductive layer 151 even when removing a film formed after the formation of a pixel electrode having the conductive layer 151 and the conductive layer 152 by a wet etching method. Consequently, the occurrence of galvanic corrosion on the pixel electrode can be suppressed. As a result, the display device 100 can be manufactured using a method with a high yield, making it a low-cost display device. Furthermore, since the occurrence of defects in the display device 100 can be suppressed, the display device 100 can be a highly reliable display device.

[0264] For example, a metallic material can be used as the conductive layer 151. Specifically, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used.

[0265] As the conductive layer 152, an oxide having one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing one or more of the following: indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0266] The conductive layer 151 may be a laminated structure of multiple layers having different materials, and the conductive layer 152 may be a laminated structure of multiple layers having different materials. In this case, the conductive layer 151 may have a layer made of a material that can be used for the conductive layer 152, such as a conductive oxide, and the conductive layer 152 may have a layer made of a material that can be used for the conductive layer 151, such as a metallic material. For example, if the conductive layer 151 has a laminated structure of two or more layers, the layer in contact with the conductive layer 152 may be a layer made of a material that can be used for the conductive layer 152.

[0267] Furthermore, the ends of the insulating layer 156 may have a tapered shape. Specifically, by having the ends of the insulating layer 156 have a tapered shape with a taper angle of less than 90°, the coverage of structures provided along the side surface of the insulating layer 156 can be improved.

[0268] (Embodiment 3) In this embodiment, a light-emitting device according to one aspect of the present invention will be described with reference to Figures 6A to 6G and Figures 7A to 7I.

[0269] [Pixel Layout] In this embodiment, a pixel layout different from that shown in Figure 5A will be described. There are no particular limitations on the arrangement of subpixels, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0270] In this embodiment, the upper surface shape of the sub-pixel shown in the figure corresponds to the upper surface shape of the light-emitting region.

[0271] Examples of the top surface shape of a sub-pixel include polygons such as triangles, quadrilaterals (including rectangles and squares), pentagons, polygons with rounded corners, ellipses, or circles.

[0272] Furthermore, the circuit layout constituting the sub-pixel is not limited to the sub-pixel range shown in the figure, but may be arranged outside of it.

[0273] The pixel 178 shown in Figure 6A has an S-stripe array applied to it. The pixel 178 shown in Figure 6A is composed of three subpixels: subpixel 110R, subpixel 110G, and subpixel 110B.

[0274] The pixel 178 shown in Figure 6B includes a sub-pixel 110R having a roughly trapezoidal or triangular shape with rounded corners, a sub-pixel 110G having a roughly trapezoidal or triangular shape with rounded corners, and a sub-pixel 110B having a roughly square or hexagonal top surface shape with rounded corners. Furthermore, sub-pixel 110R has a larger light-emitting area than sub-pixel 110G. In this way, the shape and size of each sub-pixel can be determined independently. For example, the size of a sub-pixel can be reduced to a smaller size if it has a more reliable light-emitting device.

[0275] A pentile array is applied to pixels 124a and 124b shown in Figure 6C. Figure 6C shows an example in which pixels 124a having sub-pixels 110R and 110G and pixels 124b having sub-pixels 110G and 110B are arranged alternately.

[0276] Pixels 124a and 124b shown in Figures 6D to 6F have a delta array applied. Pixel 124a has two subpixels (subpixels 110R and 110G) in the top row (1st row) and one subpixel (subpixel 110B) in the bottom row (2nd row). Pixel 124b has one subpixel (subpixel 110B) in the top row (1st row) and two subpixels (subpixels 110R and 110G) in the bottom row (2nd row).

[0277] Figure 6D shows an example where each subpixel has a roughly square top shape with rounded corners, Figure 6E shows an example where each subpixel has a circular top shape, and Figure 6F shows an example where each subpixel has a roughly hexagonal top shape with rounded corners.

[0278] In Figure 6F, each subpixel is located inside a densely arranged hexagonal region. When focusing on one subpixel, it is arranged so that it is surrounded by six other subpixels. Furthermore, subpixels that emit light of the same color are not adjacent to each other. For example, when focusing on subpixel 110R, three subpixels 110G and three subpixels 110B are arranged alternately around it.

[0279] Figure 6G shows an example where the subpixels of each color are arranged in a zigzag pattern. Specifically, in a top view, the upper edges of two subpixels aligned in the row direction (for example, subpixel 110R and subpixel 110G, or subpixel 110G and subpixel 110B) are offset.

[0280] In each pixel shown in Figures 6A to 6G, it is preferable, for example, that sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. However, the configuration of the sub-pixels is not limited to this, and the colors emitted by the sub-pixels and their order can be determined as appropriate. For example, sub-pixel 110G may emit red light, and sub-pixel 110R may emit green light.

[0281] In photolithography, the finer the pattern being processed, the more significant the effects of light diffraction become. This compromises the fidelity of transferring the photomask pattern through exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, patterns with rounded corners are likely to form. Consequently, the top surface shape of subpixels may be a polygon with rounded corners, an ellipse, or a circle.

[0282] Furthermore, in a method for manufacturing a light-emitting device according to one embodiment of the present invention, an organic compound layer is processed into an island shape using a resist mask. The resist film formed on the organic compound layer needs to be cured at a temperature lower than the heat resistance temperature of the organic compound layer. Therefore, depending on the heat resistance temperature of the organic compound layer material and the curing temperature of the resist material, the curing of the resist film may be insufficient. A resist film that is not sufficiently cured may take on a shape that deviates from the desired shape during processing. As a result, the top surface shape of the organic compound layer may become a polygon with rounded corners, an ellipse, or a circle. For example, if an attempt is made to form a resist mask with a square top surface, a resist mask with a circular top surface may be formed, resulting in a circular top surface shape for the organic compound layer.

[0283] Furthermore, in order to achieve the desired shape of the upper surface of the organic compound layer, a technique (OPC (Optical Proximity Correction) technique) may be used to pre-correct the mask pattern so that the design pattern and the transferred pattern match. Specifically, in the OPC technique, for example, a correction pattern is added to the corners of the shape on the mask pattern.

[0284] As shown in Figures 7A to 7I, a pixel can be configured to have four types of subpixels.

[0285] The pixels 178 shown in Figures 7A to 7C are arranged in a stripe pattern.

[0286] Figure 7A shows an example where each subpixel has a rectangular top surface shape, Figure 7B shows an example where each subpixel has a top surface shape formed by connecting two semicircles and a rectangle, and Figure 7C shows an example where each subpixel has an elliptical top surface shape.

[0287] The pixels 178 shown in Figures 7D to 7F are arranged in a matrix array.

[0288] Figure 7D shows an example where each subpixel has a square top surface shape, Figure 7E shows an example where each subpixel has a roughly square top surface shape with rounded corners, and Figure 7F shows an example where each subpixel has a circular top surface shape.

[0289] Figures 7G and 7H show an example where one pixel 178 is composed of two rows and three columns.

[0290] Pixel 178, shown in Figure 7G, has three subpixels (subpixel 110R, subpixel 110G, and subpixel 110B) in the top row (1st row) and one subpixel (subpixel 110W) in the bottom row (2nd row). In other words, pixel 178 has subpixel 110R in the left column (1st column), subpixel 110G in the middle column (2nd column), subpixel 110B in the right column (3rd column), and subpixel 110W extending across these three columns.

[0291] The pixel 178 shown in Figure 7H has three sub-pixels (sub-pixels 110R, 110G, and 110B) in the top row (1st row) and three sub-pixels 110W in the bottom row (2nd row). In other words, the pixel 178 has sub-pixels 110R and 110W in the left column (1st column), sub-pixels 110G and 110W in the middle column (2nd column), and sub-pixels 110B and 110W in the right column (3rd column). As shown in Figure 7H, by aligning the arrangement of sub-pixels in the top row and the bottom row, it becomes possible to efficiently remove dust that may be generated during the manufacturing process, for example. Therefore, a light-emitting device with high display quality can be provided.

[0292] In the pixel 178 shown in Figures 7G and 7H, the layout of sub-pixels 110R, 110G, and 110B is in a stripe arrangement, which improves the display quality.

[0293] Figure 7I shows an example where one pixel 178 is composed of 3 rows and 2 columns.

[0294] The pixel 178 shown in Figure 7I has a sub-pixel 110R in the top row (1st row), a sub-pixel 110G in the middle row (2nd row), a sub-pixel 110B spanning from the 1st to the 2nd row, and one sub-pixel (sub-pixel 110W) in the bottom row (3rd row). In other words, the pixel 178 has sub-pixels 110R and 110G in the left column (1st column), a sub-pixel 110B in the right column (2nd column), and a sub-pixel 110W spanning these two columns.

[0295] In the pixel 178 shown in Figure 7I, the layout of sub-pixels 110R, 110G, and 110B forms a so-called S-stripe arrangement, which improves the display quality.

[0296] The pixel 178 shown in Figures 7A to 7I is composed of four subpixels: subpixel 110R, subpixel 110G, subpixel 110B, and subpixel 110W. For example, subpixel 110R may be a subpixel that emits red light, subpixel 110G may be a subpixel that emits green light, subpixel 110B may be a subpixel that emits blue light, and subpixel 110W may be a subpixel that emits white light. At least one of subpixels 110R, 110G, 110B, and 110W may be a subpixel that emits cyan light, a subpixel that emits magenta light, a subpixel that emits yellow light, or a subpixel that emits near-infrared light.

[0297] As described above, the light-emitting device according to one aspect of the present invention can be configured to apply various layouts to pixels that consist of subpixels having light-emitting devices.

[0298] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be appropriately combined.

[0299] (Embodiment 4) This embodiment describes a display device according to one aspect of the present invention.

[0300] The display device of this embodiment can be a high-definition display device. Therefore, the display device of this embodiment can be used, for example, as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as as a display unit for wearable devices that can be worn on the head, such as VR devices such as head-mounted displays (HMDs) and AR devices such as glasses.

[0301] Furthermore, the display device of this embodiment can be a high-resolution display device or a large-screen display device. Therefore, the display device of this embodiment can be used in electronic devices with relatively large screens, such as television equipment, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal information terminals, and audio playback devices.

[0302] [Display Module] Figure 8A shows a perspective view of the display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, but may be any of the display devices 100B to 100E described later.

[0303] The display module 280 has substrates 291 and 292. The display module 280 has a display unit 281. The display unit 281 is an area in the display module 280 that displays an image, and is an area in which light from each pixel provided in the pixel unit 284, which will be described later, can be seen.

[0304] Figure 8B shows a schematic perspective view illustrating the configuration of the substrate 291. On the substrate 291, a circuit section 282, a pixel circuit section 283 on the circuit section 282, and a pixel section 284 on the pixel circuit section 283 are stacked. In addition, a terminal section 285 for connecting to the FPC 290 is provided in the portion of the substrate 291 that does not overlap with the pixel section 284. The terminal section 285 and the circuit section 282 are electrically connected by a wiring section 286, which is composed of multiple wires.

[0305] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of Figure 8B. Various configurations described in the previous embodiment can be applied to the pixels 284a.

[0306] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0307] One pixel circuit 283a is a circuit that controls the driving of multiple devices that a single pixel 284a has.

[0308] The circuit section 282 has circuits for driving each pixel circuit 283a of the pixel circuit section 283. For example, it is preferable to have one or both of a gate line drive circuit and a source line drive circuit. In addition, it may have at least one of the following: an arithmetic circuit, a memory circuit, and a power supply circuit.

[0309] The FPC 290 functions as wiring for supplying video signals or power potential, etc., to the circuit section 282 from an external source. An IC may also be mounted on the FPC 290.

[0310] Since the display module 280 can be configured such that one or both of the pixel circuit section 283 and the circuit section 282 are stacked on the lower side of the pixel section 284, the aperture ratio (effective display area ratio) of the display section 281 can be made extremely high.

[0311] Because such a display module 280 is extremely high-resolution, it can be suitably used in VR devices such as HMDs or AR devices in the form of glasses. For example, even in a configuration where the display part of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display part 281, so even when the display part is magnified with lenses, pixels are not visible, enabling a highly immersive display. Furthermore, the display module 280 is not limited to this and can be suitably used in electronic devices having relatively small display parts.

[0312] [Display device 100A] The display device 100A shown in Figure 9A includes a substrate 301, a light-emitting device 130R, a light-emitting device 130G, a light-emitting device 130B, a capacitor 240, and a transistor 310.

[0313] The substrate 301 corresponds to the substrate 291 in Figures 8A and 8B. The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, a semiconductor substrate such as a single-crystal silicon substrate can be used. The transistor 310 has a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region of the substrate 301 doped with impurities and functions as a source or drain. The insulating layer 314 is provided covering the side surface of the conductive layer 311.

[0314] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301.

[0315] Furthermore, an insulating layer 261 is provided to cover the transistor 310, and a capacitance 240 is provided on the insulating layer 261.

[0316] The capacitor 240 has a conductive layer 241, a conductive layer 245, and an insulating layer 243 located between them. The conductive layer 241 functions as one electrode of the capacitor 240, the conductive layer 245 functions as the other electrode of the capacitor 240, and the insulating layer 243 functions as the dielectric of the capacitor 240.

[0317] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to either the source or drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided covering the conductive layer 241. The conductive layer 245 is provided in the region that overlaps with the conductive layer 241 via the insulating layer 243.

[0318] An insulating layer 255 is provided covering the capacitance 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting devices 130R, 130G, and 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0319] An insulating layer 156R is provided so as to have a region that overlaps with the side surface of the conductive layer 151R, an insulating layer 156G is provided so as to have a region that overlaps with the side surface of the conductive layer 151G, and an insulating layer 156B is provided so as to have a region that overlaps with the side surface of the conductive layer 151B. Furthermore, a conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. A sacrificial layer 158R is located on the organic compound layer 103R, a sacrificial layer 158G is located on the organic compound layer 103G, and a sacrificial layer 158B is located on the organic compound layer 103B.

[0320] The conductive layers 151R, 151G, and 151B are electrically connected to either the source or drain of the transistor 310 by the insulating layers 243, 255, 174, and plugs 256 embedded in the insulating layer 175, the conductive layer 241 embedded in the insulating layer 254, and plugs 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0321] Furthermore, a protective layer 131 is provided on the light-emitting devices 130R, 130G, and 130B. A substrate 120 is bonded to the protective layer 131 by a resin layer 122. Details of the components from the light-emitting devices 130 to the substrate 120 can be found in the embodiments described above. The substrate 120 corresponds to the substrate 292 in Figure 8A.

[0322] Figure 9B is a modified example of the display device 100A shown in Figure 9A. The display device shown in Figure 9B has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. In the display device shown in Figure 9B, the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light.

[0323] [Display device 100B] Figure 10 shows a perspective view of the display device 100B, and Figure 11 shows a cross-sectional view of the display device 100C.

[0324] The display device 100B has a configuration in which substrate 352 and substrate 351 are bonded together. In Figure 10, substrate 352 is shown by a dashed line.

[0325] The display device 100B includes a pixel section 177, a connection section 140, a circuit 356, and wiring 355, etc. Figure 10 shows an example in which an IC 354 and an FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Figure 10 can also be called a display module having a display device 100B, an IC (integrated circuit), and an FPC. Here, a display module is a display device on which a connector such as an FPC is attached to the substrate, or on which an IC is mounted.

[0326] The connection portion 140 is provided on the outside of the pixel portion 177. There may be one or more connection portions 140. The connection portion 140 is electrically connected to the common electrode of the light-emitting device and the conductive layer, and can supply potential to the common electrode.

[0327] For example, a scan line drive circuit can be used as circuit 356.

[0328] The wiring 355 has the function of supplying signals and power to the pixel unit 177 and the circuit 356. These signals and power are input to the wiring 355 from an external source via the FPC 353 or from the IC 354.

[0329] Figure 10 shows an example in which IC 354 is provided on the substrate 351 using the COG (Chip On Glass) method or the COF (Chip On Film) method. IC 354 can be an IC having, for example, a scan line drive circuit or a signal line drive circuit. Note that the display device 100B and the display module may be configured without an IC. Alternatively, the IC may be mounted on the FPC, for example, using the COF method.

[0330] FIG. 11 shows an example of a cross-section when a part of the region including the FPC 353, a part of the circuit 356, a part of the pixel portion 177, a part of the connection portion 140, and a part of the region including the end portion of the display device 100B in FIG. 10 are each cut, as the display device 100C.

[0331] [Display Device 100C] The display device 100C shown in FIG. 11 has a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, a light-emitting device 130B that emits blue light, etc. between the substrate 351 and the substrate 352.

[0332] Details of the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B can be referred to the above-described embodiments.

[0333] The light-emitting device 130R has a conductive layer 224R, a conductive layer 151R on the conductive layer 224R, and a conductive layer 152R on the conductive layer 151R. The light-emitting device 130G has a conductive layer 224G, a conductive layer 151G on the conductive layer 224G, and a conductive layer 152G on the conductive layer 151G. The light-emitting device 130B has a conductive layer 224B, a conductive layer 151B on the conductive layer 224B, and a conductive layer 152B on the conductive layer 151B.

[0334] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. The end portion of the conductive layer 151R is located outside the end portion of the conductive layer 224R. An insulating layer 156R is provided so as to have a region in contact with the side surface of the conductive layer 151R, and a conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R.

[0335] Regarding the conductive layer 224G, the conductive layer 151G, the conductive layer 152G, the insulating layer 156G in the light-emitting device 130G and the conductive layer 224B, the conductive layer 151B, the conductive layer 152B, the insulating layer 156B in the light-emitting device 130B, since they are the same as the conductive layer 224R, the conductive layer 151R, the conductive layer 152R, the insulating layer 156R in the light-emitting device 130R, detailed description thereof is omitted.

[0336] In the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, recesses are formed so as to cover the openings provided in the insulating layer 214. The layer 128 is embedded in the recesses.

[0337] The layer 128 has a function of filling and planarizing the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B. On the conductive layer 224R, the conductive layer 224G, the conductive layer 224B, and the layer 128, a conductive layer 151R, a conductive layer 151G, and a conductive layer 151B that are electrically connected to the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B are provided. Therefore, the region overlapping the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B can also be used as a light-emitting region, and the aperture ratio of the pixel can be increased.

[0338] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be appropriately used for the layer 128. In particular, the layer 128 is preferably formed using an insulating material, and particularly preferably formed using an organic insulating material. For example, the organic insulating material that can be used for the insulating layer 127 described above can be applied to the layer 128.

[0339] A protective layer 131 is provided on the light-emitting devices 130R, the light-emitting devices 130G, and the light-emitting devices 130B. The protective layer 131 and the substrate 352 are adhered via an adhesive layer 142. A light-shielding layer 157 is provided on the substrate 352. For the encapsulation of the light-emitting device 130, a solid encapsulation structure, a hollow encapsulation structure, or the like can be applied. In FIG. 11, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, and a solid encapsulation structure is applied. Alternatively, the space may be filled with an inert gas (such as nitrogen or argon), and a hollow encapsulation structure may be applied. At this time, the adhesive layer 142 may be provided in a frame shape so as not to overlap the light-emitting device. Also, the space may be filled with a resin different from the adhesive layer 142 provided in a frame shape.

[0340] Figure 11 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B; a conductive layer 151C obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B; and a conductive layer 152C obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. Figure 11 also shows an example in which an insulating layer 156C is provided so as to have a region that overlaps with the side surface of conductive layer 151C.

[0341] The display device 100C is a top-emission type. The light emitted by the light-emitting device is emitted towards the substrate 352. It is preferable to use a material with high transmittance to visible light for the substrate 352. The pixel electrodes contain a material that reflects visible light, and the counter electrodes (common electrodes 155) contain a material that transmits visible light.

[0342] On the substrate 351, insulating layers 211, 213, 215, and 214 are provided in this order. A portion of insulating layer 211 functions as a gate insulating layer for each transistor. A portion of insulating layer 213 functions as a gate insulating layer for each transistor. Insulating layer 215 is provided covering the transistors. Insulating layer 214 is provided covering the transistors and functions as a planarization layer. The number of gate insulating layers and insulating layers covering the transistors are not limited and may be a single layer or two or more layers, respectively.

[0343] It is preferable to use an inorganic insulating film as the insulating layer 211, insulating layer 213, and insulating layer 215.

[0344] An organic insulating layer is preferred for the insulating layer 214, which functions as a planarizing layer.

[0345] Transistors 201 and 205 have a conductive layer 221 that functions as a gate, an insulating layer 211 that functions as a gate insulating layer, conductive layers 222a and 222b that function as source and drain, a semiconductor layer 231, an insulating layer 213 that functions as a gate insulating layer, and a conductive layer 223 that functions as a gate.

[0346] A connection portion 204 is provided in the region of substrate 351 where substrate 352 does not overlap. At the connection portion 204, the source electrode or drain electrode of transistor 201 is electrically connected to FPC 353 via conductive layer 166 and connection layer 242. The conductive layer 166 is shown as an example of a laminated structure consisting of a conductive film obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. This allows the connection portion 204 and FPC 353 to be electrically connected via the connection layer 242.

[0347] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 that faces the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, at connection points 140, and in circuits 356, etc. Various optical components can also be arranged on the outside of the substrate 352.

[0348] Materials suitable for use on substrate 120 can be applied to substrate 351 and substrate 352, respectively.

[0349] As the adhesive layer 142, a material that can be used for the resin layer 122 can be applied.

[0350] As the connecting layer 242, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) can be used.

[0351] [Display device 100D] The display device 100D shown in Figure 12 differs from the display device 100C shown in Figure 11 mainly in that it is a bottom-emission type display device.

[0352] The light emitted by the light-emitting device is emitted towards the substrate 351. It is preferable to use a material with high transmittance to visible light for the substrate 351. On the other hand, the light transmittance of the material used for the substrate 352 is not a requirement.

[0353] It is preferable to form a light-shielding layer 317 between the substrate 351 and the transistor 201, and between the substrate 351 and the transistor 205. Figure 12 shows an example in which a light-shielding layer 317 is provided on the substrate 351, an insulating layer 153 is provided on the light-shielding layer 317, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0354] The light-emitting device 130R includes a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R.

[0355] The light-emitting device 130B includes a conductive layer 112B, a conductive layer 126B on the conductive layer 112B, and a conductive layer 129B on the conductive layer 126B.

[0356] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are made of materials with high transmittance to visible light. It is preferable to use a material that reflects visible light for the second electrode 102.

[0357] Although the light-emitting device 130G is not shown in Figure 12, it is also provided.

[0358] Furthermore, while Figure 12 and other figures show an example where the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited.

[0359] [Display Device 100D2] The display device 100D2 shown in Figure 13 is an example of a bottom-emission type display device, different from the display device 100D shown in Figure 12. The display device 100D2 differs from the display device 100D in that it has an organic resin layer 180. Note that in the figure, the reference numerals for components that are the same as in Figure 12 may be omitted, and details can be found in the description in Figure 12.

[0360] Furthermore, Figure 13B shows the top view layout of a pixel 178 (pixels 178a and 178b) having sub-pixels 110 (sub-pixels 110R, 110G, 110B, and 110W), and Figure 13C shows the top view of the organic resin layer 180 in the region where sub-pixels 110R and 110G of pixel 178 are formed. The space between the light-shielding layers 317 is the width 110Rw of the light-emitting region of sub-pixel 110R.

[0361] As shown in Figure 13A, the organic resin layer 180 is provided on the insulating layer 214. As shown in the region enclosed by the dashed line in Figure 13A and in Figure 13C, the organic resin layer 180 has curved recesses 181 (recesses 181a and 181b) in at least the region where subpixels are formed. The recesses 181 may also be provided outside the light-emitting region, such as recess 181c. By providing recess 181c, the light emitted in the region overlapping with the light-shielding layer 317 or the light that has traveled to the region overlapping with the light-shielding layer 317 can be refracted and extracted from the light-emitting region, thereby improving the luminous efficiency.

[0362] Multiple recesses 181 may be formed on the matrix. Recesses 181a and 181b may be in contact with each other, or there may be a plane between them.

[0363] Furthermore, in Figure 13, the upper surface shape of the recess is shown as a hexagon (Figure 13C) and the cross-sectional shape as a semicircle (Figure 13A), but other shapes may be used as needed. For example, the upper surface shape of the recess may be a triangle, a quadrilateral (including rectangles and squares), a pentagon or other polygon, a polygon with rounded corners, an ellipse, or a circle.

[0364] As the organic resin layer 180, an insulating layer having an organic material can be used. For example, as the organic resin layer 180, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used. Alternatively, as the organic resin layer 180, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used.

[0365] Furthermore, a photosensitive resin can be used as the organic resin layer 180. A photoresist may be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0366] The organic resin layer 180 may contain a material that absorbs visible light. For example, the organic resin layer 180 itself may be composed of a material that absorbs visible light, or the organic resin layer 180 may contain a pigment that absorbs visible light. As the organic resin layer 180, for example, a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light, or a resin that contains carbon black as a pigment and functions as a black matrix can be used.

[0367] Also, on the organic resin layer 180, there are a first electrode 101 (first electrodes 101R and 101W), and an organic compound layer 103 on the first electrode 101. The ends of the first electrode 101 and the organic compound layer 103 may be covered with an insulating layer 127.

[0368] Further, the first electrode 101 formed on the organic resin layer 180 has a recess similarly along the recess of the organic resin layer 180. Furthermore, the organic compound layer 103 formed on the first electrode 101 has a recess similarly along the recess of the first electrode 101. Further, the common layer 104 formed on the organic compound layer 103 has a recess similarly along the recess of the organic compound layer 103. Further, the second electrode 102 formed on the common layer 104 has a recess similarly along the recess of the common layer 104. That is, the recesses of the organic resin layer 180, the first electrode 101, the organic compound layer 103, the common layer 104, and the second electrode 102 have a structure that overlaps each other.

[0369] Also, there are a common layer 104 on the organic compound layer 103 and the insulating layer 127, and a second electrode 102 on the common layer 104. A protective layer 131 is provided on the second electrode 102, and it has a structure that is bonded to the substrate 352 via an adhesive layer 142.

[0370] Note that in FIG. 13, the light-emitting devices 130G and 130B are not shown, but the light-emitting devices 130G and 130B are also provided.

[0371] [Display device 100E] The display device 100E shown in Figure 14 is a modified version of the display device 100C shown in Figure 11, and differs from the display device 100C mainly in that it has a colored layer 132R, a colored layer 132G, and a colored layer 132B.

[0372] In the display device 100E, the light-emitting device 130 has a region that overlaps with one of the colored layers 132R, 132G, and 132B. The colored layers 132R, 132G, and 132B can be provided on the substrate 351 side of the substrate 352. The edges of the colored layer 132R, the edges of the colored layer 132G, and the edges of the colored layer 132B can overlap with the light-shielding layer 157.

[0373] In the display device 100E, the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may also be configured to have the colored layers 132R, 132G, and 132B placed between the protective layer 131 and the adhesive layer 142.

[0374] [Display device 100E2] The display device 100E2 shown in Figures 15A, 15B, and 15C is a modified version of the display device 100E shown in Figure 14, and has a microlens 182 on the colored layer 132R, colored layer 132G, and colored layer 132B. Note that in the figures, the reference numerals for components that are the same as in Figure 14 may be omitted, and details can be found in the description in Figure 14.

[0375] Figure 15B shows the top view layout of a pixel 178 (pixels 178a and 178b) having sub-pixels 110 (sub-pixels 110R, 110G, and 110B), and Figure 15C shows the top view of the microlens 182 in the region where the sub-pixels 110R and 110G of pixel 178 are formed. The region where the common electrode 155 and the organic compound layer 103 are in contact is the width 110Gw of the light-emitting region of sub-pixel 110G.

[0376] The display device 100E2 shown in Figure 13A has a planarization film 143 on a protective layer 131, and a colored layer 132R, a colored layer 132G, and a colored layer 132B on the planarization film 143. A planarization film 144 is provided so as to cover the colored layers 132R, 132G, and 132B. A microlens 182 is provided on the planarization film 144.

[0377] Furthermore, as shown in Figure 15C, the microlenses 182 may be provided for each sub-pixel in the region where the sub-pixels are formed.

[0378] In Figure 15C, the upper surface shape of the microlens 182 is shown as a hexagon, but other shapes may be used as needed. For example, the upper surface shape of the recess may be a triangle, a quadrilateral (including rectangles and squares), a pentagon or other polygon, a polygon with rounded corners, an ellipse, or a circle.

[0379] The microlens 182 can be formed using the same material as the organic resin layer 180.

[0380] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be appropriately combined.

[0381] (Embodiment 5) This embodiment describes an electronic device according to one aspect of the present invention.

[0382] The electronic device of this embodiment has a light-emitting device according to one aspect of the present invention in its display unit. The light-emitting device according to one aspect of the present invention is highly reliable and easily capable of high-definition and high-resolution displays. Therefore, it can be used in the display units of various electronic devices.

[0383] Examples of electronic devices include television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, and other electronic devices with relatively large screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, personal digital assistants, and audio playback devices.

[0384] In particular, since the light-emitting device according to one aspect of the present invention can increase resolution, it can be suitably used in electronic devices having a relatively small display area. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), as well as wearable devices that can be attached to the head, such as VR devices such as head-mounted displays, AR devices such as glasses, and MR (Mixed Reality) devices.

[0385] A light-emitting device according to one aspect of the present invention preferably has an extremely high resolution such as HD (1280 x 720 pixels), FHD (1920 x 1080 pixels), WQHD (2560 x 1440 pixels), WQXGA (2560 x 1600 pixels), 4K (3840 x 2160 pixels), or 8K (7680 x 4320 pixels). In particular, a resolution of 4K, 8K, or higher is preferred. Furthermore, the pixel density (resolution) of the light-emitting device according to one aspect of the present invention is preferably 100 ppi or more, preferably 300 ppi or more, more preferably 500 ppi or more, more preferably 1000 ppi or more, more preferably 2000 ppi or more, more preferably 3000 ppi or more, more preferably 5000 ppi or more, and even more preferably 7000 ppi or more. By using a light-emitting device having high resolution and / or high detail, it is possible to further enhance the sense of presence and depth. Furthermore, there are no particular limitations on the aspect ratio of the light-emitting device according to one embodiment of the present invention. For example, the light-emitting device can accommodate various aspect ratios such as 1:1 (square), 4:3, 16:9, and 16:10.

[0386] The electronic device of this embodiment may have sensors (including those with functions to measure force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation).

[0387] 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.

[0388] Figures 16A to 16D illustrate an example of a wearable device that can be worn on the head. These wearable devices have at least one of the following functions: a function to display AR content, a function to display VR content, a function to display SR (Substantial Reality) content, and a function to display MR content. By having an electronic device that has the function to display at least one of the following content types, such as AR, VR, SR, and MR, it is possible to enhance the user's sense of immersion.

[0389] The electronic device 700A shown in Figure 16A and the electronic device 700B shown in Figure 16B each include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0390] A light-emitting device according to one embodiment of the present invention can be applied to the display panel 751. Therefore, a highly reliable electronic device can be made.

[0391] Electronic devices 700A and 700B can project an image displayed on the display panel 751 onto the display area 756 of the optical element 753. Because the optical element 753 is translucent, the user can see the image displayed on the display area superimposed on the transmitted image visible through the optical element 753. Therefore, electronic devices 700A and 700B are electronic devices capable of AR display.

[0392] Electronic devices 700A and 700B may be equipped with cameras capable of capturing images of the area in front of them as imaging units. Furthermore, electronic devices 700A and 700B may each be equipped with acceleration sensors such as gyro sensors to detect the orientation of the user's head and display an image corresponding to that orientation in the display area 756.

[0393] The communications unit has a wireless communication device, which can supply, for example, a video signal. Alternatively, instead of the wireless communication device, or in addition to the wireless communication device, it may be equipped with a connector to which a cable supplying video signals and power potential can be connected.

[0394] Furthermore, electronic devices 700A and 700B are equipped with batteries that can be charged wirelessly, wired, or both.

[0395] The housing 721 may be equipped with a touch sensor module. The touch sensor module has the function of detecting when the outer surface of the housing 721 is touched. The touch sensor module can detect the user's tap or slide operations and perform various processes. For example, a tap operation can be used to pause or resume the video, and a slide operation can be used to fast forward or rewind. Furthermore, by providing a touch sensor module in each of the two housings 721, the range of operations can be expanded.

[0396] Various types of touch sensors can be used in the touch sensor module. For example, various methods such as capacitive, resistive, infrared, electromagnetic induction, surface acoustic wave, or optical sensors can be employed. In particular, it is preferable to apply capacitive or optical sensors to the touch sensor module.

[0397] When using an optical touch sensor, a photoelectric conversion device (also called a photoelectric conversion element) can be used as the light-receiving device. The active layer of the photoelectric conversion device can be made of either an inorganic semiconductor or an organic semiconductor, or both.

[0398] The electronic device 800A shown in Figure 16C and the electronic device 800B shown in Figure 16D each include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0399] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 820. Therefore, a highly reliable electronic device can be made.

[0400] The display unit 820 is located inside the housing 821 in a position visible through the lens 832. Furthermore, by displaying different images on a pair of display units 820, a three-dimensional display using parallax can be achieved.

[0401] Electronic devices 800A and 800B can each be described as electronic devices for VR. A user wearing electronic device 800A or electronic device 800B can view the image displayed on the display unit 820 through the lens 832.

[0402] It is preferable that electronic devices 800A and 800B each have a mechanism that allows adjustment of the left and right positions of the lens 832 and the display unit 820 so that they are in the optimal position according to the user's eye position. It is also preferable that they have a mechanism that adjusts the focus by changing the distance between the lens 832 and the display unit 820.

[0403] The attachment portion 823 allows the user to attach the electronic device 800A or 800B to their head. Note that, for example, in Figure 16C, it is illustrated as having a shape similar to the temples (or arms, etc.) of eyeglasses, but it is not limited to this. The attachment portion 823 only needs to be wearable by the user; for example, it may be helmet-shaped or band-shaped.

[0404] The imaging unit 825 has the function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, multiple cameras may be provided to accommodate multiple angles of view, such as telephoto and wide-angle.

[0405] Although an example with an imaging unit 825 is shown here, any distance measuring sensor (hereinafter also referred to as a detection unit) capable of measuring the distance to an object can be provided. In other words, the imaging unit 825 is one form of the detection unit. As the detection unit, for example, an image sensor or a distance image sensor such as LiDAR (Light Detection and Ranging) can be used. By using the image obtained by the camera and the image obtained by the distance image sensor, more information can be acquired, enabling more accurate gesture control.

[0406] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone. For example, a configuration having such a vibration mechanism can be applied to one or more of the display unit 820, housing 821, and mounting unit 823. This eliminates the need for separate audio equipment such as headphones, earphones, or speakers, allowing users to enjoy video and audio simply by wearing the electronic device 800A.

[0407] Electronic devices 800A and 800B may each have input terminals. Cables can be connected to the input terminals to supply video signals from video output devices, etc., and power for charging batteries provided in the electronic devices.

[0408] An electronic device according to one aspect of the present invention may have a function for wireless communication with an earphone 750. The earphone 750 has a communication unit (not shown) and has a wireless communication function. The earphone 750 can receive information (e.g., voice data) from the electronic device through its wireless communication function. For example, the electronic device 700A shown in Figure 16A has a function for transmitting information to the earphone 750 through its wireless communication function. Also, for example, the electronic device 800A shown in Figure 16C has a function for transmitting information to the earphone 750 through its wireless communication function.

[0409] Furthermore, the electronic device may have an earphone section. The electronic device 700B shown in Figure 16B has an earphone section 727. For example, the earphone section 727 and the control unit can be connected to each other by a wire. Part of the wiring connecting the earphone section 727 and the control unit may be located inside the housing 721 or the mounting section 723.

[0410] Similarly, the electronic device 800B shown in Figure 16D has an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be connected to each other by wire. Part of the wiring connecting the earphone unit 827 and the control unit 824 may be located inside the housing 821 or the mounting unit 823. Also, the earphone unit 827 and the mounting unit 823 may have magnets. This allows the earphone unit 827 to be fixed to the mounting unit 823 by magnetic force, making storage easier and preferable.

[0411] Furthermore, the electronic device may have an audio output terminal to which earphones or headphones can be connected. The electronic device may also have an audio input terminal and / or an audio input mechanism. For example, a sound-collecting device such as a microphone can be used as the audio input mechanism. By having an audio input mechanism, the electronic device may be given the function of a so-called headset.

[0412] Thus, as one embodiment of the present invention, both eyeglass-type (electronic devices 700A and 700B, etc.) and goggle-type (electronic devices 800A and 800B, etc.) are preferred as electronic devices.

[0413] Furthermore, an electronic device according to one aspect of the present invention can transmit information to earphones via wired or wireless means.

[0414] The electronic device 6500 shown in Figure 17A is a portable information terminal that can be used as a smartphone.

[0415] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508, etc. The display unit 6502 has a touch panel function.

[0416] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 6502. Therefore, a highly reliable electronic device can be made.

[0417] Figure 17B is a schematic cross-sectional view of the housing 6501 including the end on the microphone 6506 side.

[0418] A light-transmitting protective member 6510 is provided on the display side of the housing 6501, and the display panel 6511, optical member 6512, touch sensor panel 6513, printed circuit board 6517, and battery 6518 are arranged in the space enclosed by the housing 6501 and the protective member 6510.

[0419] The protective member 6510 is fixed to the display panel 6511, the optical member 6512, and the touch sensor panel 6513 by an adhesive layer (not shown).

[0420] In the area outside the display unit 6502, a portion of the display panel 6511 is folded back, and the FPC 6515 is connected to this folded portion. IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to terminals provided on the printed circuit board 6517.

[0421] A light-emitting device according to one embodiment of the present invention can be applied to the display panel 6511. This makes it possible to realize an extremely lightweight electronic device. Furthermore, because the display panel 6511 is extremely thin, it is possible to incorporate a large-capacity battery 6518 while keeping the thickness of the electronic device low. In addition, by folding back a part of the display panel 6511 and placing the connection part with the FPC 6515 on the back of the pixel section, an electronic device with a narrow bezel can be realized.

[0422] Figure 17C shows an example of a television system. The television system 7100 has a display unit 7000 incorporated into a housing 7171. Here, the housing 7171 is shown supported by a stand 7173.

[0423] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0424] The television device 7100 shown in Figure 17C can be operated using the operation switches on the housing 7171 and a separate remote control unit 7151. Alternatively, the display unit 7000 may be equipped with a touch sensor, and the television device 7100 can be operated by touching the display unit 7000 with a finger or the like. The remote control unit 7151 may have a display unit that displays information output from the remote control unit 7151. 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 7151.

[0425] The television system 7100 is configured to include a receiver and a modem, etc. 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.

[0426] Figure 17D shows an example of a notebook personal computer. The notebook personal computer 7200 has a casing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214, etc. A display unit 7000 is incorporated into the casing 7211.

[0427] A light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0428] Figures 17E and 17F show examples of digital signage.

[0429] The digital signage 7300 shown in Figure 17E includes a housing 7301, a display unit 7000, and a speaker 7303, etc. Furthermore, it may include LED lamps, operation keys (including a power switch or operation switch), connection terminals, various sensors, a microphone, etc.

[0430] Figure 17F shows a digital signage 7400 mounted on a cylindrical column 7401. The digital signage 7400 has a display unit 7000 that is provided along the curved surface of the column 7401.

[0431] In Figures 17E and 17F, a light-emitting device according to one embodiment of the present invention can be applied to the display unit 7000. Therefore, a highly reliable electronic device can be made.

[0432] 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.

[0433] 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.

[0434] Furthermore, as shown in Figures 17E and 17F, it is preferable that the digital signage 7300 or digital signage 7400 can be linked wirelessly with an information terminal 7311 or information terminal 7411 such as a smartphone owned by the user. 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.

[0435] 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 an unspecified number of users to participate in and enjoy the game simultaneously.

[0436] The electronic device shown in Figures 18A to 18G includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or operation switch), connection terminals 9006, a sensor 9007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 9008, and the like.

[0437] The electronic devices shown in Figures 18A to 18G have various functions. For example, they may have functions to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date or time, a function to control processing by various software (programs), a wireless communication function, a function to read and process programs or data recorded on a recording medium, etc. However, the functions of electronic devices are not limited to these and can have various functions. Electronic devices may have multiple display units. Furthermore, electronic devices may be equipped with a camera, etc., and have functions to capture still images or videos and save them on a recording medium (external or built into the camera), a function to display the captured images on a display unit, etc.

[0438] Details of the electronic equipment shown in Figures 18A to 18G will be explained below.

[0439] Figure 18A is a perspective view showing a personal information terminal 9171. The personal information terminal 9171 can be used, for example, as a smartphone. The personal information terminal 9171 may also be equipped with a speaker 9003, a connection terminal 9006, or a sensor 9007. Furthermore, the personal information terminal 9171 can display text and image information on multiple surfaces. Figure 18A shows an example where three icons 9050 are displayed. Information 9051, indicated by a dashed rectangle, can also be displayed on other surfaces of the display unit 9001. Examples of information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of emails or SNS messages, the sender's name, date and time, time, battery level, signal strength, etc. Alternatively, icons 9050, etc., may be displayed in the position where the information 9051 is displayed.

[0440] Figure 18B is a perspective view showing the personal digital assistant (PDA) 9172. The PDA 9172 has the function of displaying information on three or more sides of the display unit 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different sides. For example, a user can check information 9053, which is displayed in a position that can be observed from above the PDA 9172, while the PDA 9172 is stored in the breast pocket of their clothing. The user can check the display without taking the PDA 9172 out of their pocket and decide, for example, whether or not to answer a call.

[0441] Figure 18C is a perspective view showing the tablet terminal 9173. The tablet terminal 9173 can run various applications, such as mobile phone calls, email, document viewing and creation, music playback, internet communication, and computer games. The tablet terminal 9173 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000. The left side of the housing 9000 has operation keys 9005 as buttons for operation, and the bottom has connection terminals 9006.

[0442] Figure 18D is a perspective view showing a wristwatch-type personal information terminal 9200. The personal information terminal 9200 can be used, for example, as a smartwatch (registered trademark). The display unit 9001 has a curved display surface, allowing it to display information along the curved surface. The personal information terminal 9200 can also make hands-free calls by communicating with, for example, a wireless communication headset. Furthermore, the personal information terminal 9200 can transmit data to other information terminals and be charged via a connection terminal 9006. The charging operation may be performed by wireless power supply.

[0443] Figures 18E to 18G are perspective views showing a foldable portable information terminal 9201. Figure 18E shows the portable information terminal 9201 in an unfolded state, Figure 18G shows it in a folded state, and Figure 18F shows a perspective view of the state in between, transitioning from one of Figures 18E or 18G to the other. The portable information terminal 9201 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state. The display unit 9001 of the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display unit 9001 can be bent with a radius of curvature of 0.1 mm to 150 mm.

[0444] This embodiment can be appropriately combined with other embodiments or examples. Furthermore, if multiple configuration examples are shown within a single embodiment in this specification, these configuration examples can be appropriately combined.

[0445] In this embodiment, light-emitting devices 1A to 1D, which are light-emitting devices according to one aspect of the present invention, are fabricated, and the results of measuring the characteristics of each device are described. A fluorescent light-emitting material was used for the light-emitting layer.

[0446] The structural formulas of the organic compounds used in light-emitting devices 1A to 1D are shown below.

[0447]

[0448] As shown in Figure 19, each light-emitting device has a sequential stacking structure in which a hole injection layer 911, a hole transport layer 912 (second hole transport layer 912_2 and first hole transport layer 912_1), a light-emitting layer 913, an electron transport layer 914 (first electron transport layer 914_1 and second electron transport layer 914_2), and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a glass substrate 900, and a second electrode 902 is stacked on the electron injection layer 915.

[0449] <Method for fabricating the light-emitting device 1A> A first electrode 901 was formed on a glass substrate 900 by sputtering indium tin oxide (ITSO) containing silicon oxide to a thickness of 110 nm as a transparent electrode. The electrode area was 4 mm².２ (2 mm x 2 mm)

[0450] Next, as a pretreatment for forming the light-emitting device on the substrate, the substrate surface was washed with water and fired at 200°C for 1 hour. After that, 1 × 10 −４ The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus. After that, it was allowed to cool naturally.

[0451] Next, the substrate on which the first electrode 901 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 901 is formed faces downwards. N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBiF) and an electron acceptor material (OCHD-003) with a molecular weight of 672 and containing fluorine are co-deposited on the first electrode 901 in a weight ratio of 1:0.03 (= PCBiF:OCHD-003) and with a film thickness of 10 nm to form a hole injection layer 911.

[0452] Next, a second hole transport layer 912_2 was formed on the hole injection layer 911 by depositing PCBiF to a thickness of 90 nm. Then, a first hole transport layer 912_1 was formed by depositing N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP) to a thickness of 10 nm.

[0453] Next, on the first hole transport layer 912_1, 1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02-d5), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene-1,2,3,4,5,6,7,8-d8 (abbreviation: αN-βNPanth-d8), and N,N'-diphenyl-N,N'-bi Su(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02) was co-deposited with Bnf(II)PhA-02-d5:αN-βNPAnth-d8:3,10PCA2Nbf(IV)-02 in a weight ratio of 0.5:0.5:0.015 (=Bnf(II)PhA-02-d5:αN-βNPAnth-d8:3,10PCA2Nbf(IV)-02) and with a film thickness of 25 nm to form an emissive layer 913.

[0454] Next, a first electron transport layer 914_1 was formed on the light-emitting layer 913 by depositing 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq) to a thickness of 10 nm. Subsequently, a second electron transport layer 914_2 was formed by depositing 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P) to a thickness of 15 nm.

[0455] Next, lithium fluoride (LiF) was deposited onto the second electron transport layer 914_2 to a thickness of 1 nm to form an electron injection layer 915.

[0456] Next, a second electrode 902 was formed by depositing aluminum (Al) onto the electron injection layer 915 to a thickness of 150 nm, thereby fabricating the light-emitting device 1A.

[0457] <Method for fabricating light-emitting device 1B> Light-emitting device 1B differs from light-emitting device 1A in the configuration of the light-emitting layer 913. Specifically, in light-emitting device 1A, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with 1-(10-phenyl-9-antlyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02). The other components were fabricated in the same manner as light-emitting device 1A.

[0458] <Method for fabricating light-emitting device 1C> Light-emitting device 1C differs from light-emitting device 1A in the configuration of the light-emitting layer 913. Specifically, in light-emitting device 1A, αN-βNPanth-d8 used as the second host in the light-emitting layer 913 was replaced with 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPanth). The other components were fabricated in the same manner as light-emitting device 1A.

[0459] <Method for fabricating light-emitting device 1D> Light-emitting device 1D differs from light-emitting device 1C in the configuration of the light-emitting layer 913. Specifically, in light-emitting device 1A, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with 1-(10-phenyl-9-antlyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02). The other components were fabricated in the same manner as light-emitting device 1C.

[0460] The light-emitting device structures of light-emitting devices 1A to 1D are summarized in Table 3 below. Condition 1X is shown in Appendix Table 4.

[0461]

[0462]

[0463] Furthermore, the GSP-slope of Bnf(II)PhA-02-d5 used in any of the light-emitting devices 1A to 1D was 35.2 mV / nm, the GSP-slope of DBfBB1TP was 13.3 mV / nm, and the GSP-slope of αN-βNPanth was 4.6 mV / nm. The GSP-slope of Bnf(II)PhA-02-d5 was greater than that of DBfBB1TP. In addition, the average of the GSP-slope of Bnf(II)PhA-02-d5 and the GSP-slope of αN-βNPanth was greater than that of DBfBB1TP. The measurement method for the GSP-slope can be found in Embodiment 1.

[0464] <Light-emitting device characteristics> The above light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the characteristics of the light-emitting device were measured.

[0465] Figure 20 shows the luminance-current density characteristics of each light-emitting device, Figure 21 shows the luminance-voltage characteristics, Figure 22 shows the current efficiency-luminance characteristics, Figure 23 shows the current density-voltage characteristics, Figure 24 shows the power efficiency-luminance characteristics, Figure 25 shows the external quantum efficiency-luminance characteristics, and Figure 26 shows the field emission spectrum.

[0466] Furthermore, the brightness of each light-emitting device is 1000 cd / m². ２ Table 5 below shows the main characteristics in the vicinity. A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum. Power efficiency and external quantum efficiency were calculated using luminance and emission spectrum measured from the front of the substrate's light-emitting surface with a spectroradiometer, assuming a Lambertsian light distribution pattern.

[0467]

[0468] From Figure 26 and the table above, it became clear that light-emitting devices 1A to 1D are light-emitting devices with good characteristics, exhibiting blue light emission derived from 3,10PCA2Nbf(IV)-02. Furthermore, from Figures 20 to 26 and Table 5 above, it became clear that light-emitting devices 1A to 1C exhibit performance equivalent to that of the comparative light-emitting device 1D.

[0469] This is because a heteroaromatic ring compound was used as the first host and a hydrocarbon compound was used as the second host, resulting in devices with low driving voltage, low power consumption, and high luminous efficiency in both types of light-emitting elements. This is thought to be because the devices using a heteroaromatic ring compound as the first host and a hydrocarbon compound as the second host exhibited improved carrier implantation, transport, or both. Furthermore, it is believed that the improved carrier implantation or transport also led to an improved carrier balance, resulting in good luminous efficiency.

[0470] From the above results, it was found that the light-emitting device according to one aspect of the present invention is a light-emitting device with high luminous efficiency (power efficiency, current efficiency, and external quantum efficiency) and low driving voltage.

[0471] <Reliability Test Results> Furthermore, reliability tests were conducted on light-emitting devices 1A to 1D. Constant current density (50 [mA / cm²] ２ Figure 27 shows the time variation of the normalized brightness during operation. In Figure 27, the vertical axis represents the brightness (%) normalized with the brightness at the start of the element's operation set to 100%, and the horizontal axis represents the operation time (h) of the element.

[0472] Figure 27 shows that the LT95(h) values, which represent the elapsed time until the measured brightness decreases to 95% of the initial brightness, were 270 hours for light-emitting device 1A, 171 hours for light-emitting device 1B, 265 hours for light-emitting device 1C, and 141 hours for light-emitting device 1D. Therefore, it was found that light-emitting devices 1A to 1C have better reliability than the comparative light-emitting device 1D. This is thought to be because the deuterization of the host stabilizes the excited state host material generated by the recombination of carriers in the light-emitting layer host material, thereby suppressing degradation. In particular, by using a heteroaromatic ring compound for the first host and a hydrocarbon compound for the second host, the carrier implantability, or transportability, or both, improved, and the carrier balance of the entire device improved, resulting in a significant effect in suppressing the degradation of the light-emitting layer host material. It can be said that a synergistic effect was obtained by deuterizing each of the mixed hosts.

[0473] In particular, it was found that light-emitting devices 1A and 1C, which used the deuterated first host, exhibited nearly twice the reliability of the comparative light-emitting device 1D. This result indicates that a greater reliability improvement can be obtained by deuterating the heteroaromatic ring compound, which is the first host. In other words, it was found that deuterating an organic compound having a heteroaromatic ring (the first host), which is thought to have higher hole transportability compared to the hydrocarbon compound, the second host, is more effective in extending the lifespan of the device. The heteroaromatic ring compound, the first host, plays a role in injecting and transporting holes into the entire light-emitting layer. On the other hand, the excited state of the organic compound having a heteroaromatic ring (the first host) is more prone to instability than the hydrocarbon compound, the second host, because it has a carbon-heteroatom bond. Therefore, it is thought that a significant reliability improvement can be obtained by deuterating an organic compound having a heteroaromatic ring (the first host), which is thought to have higher hole transportability compared to the hydrocarbon compound, the second host. Furthermore, the effect of deuterating the first host, the heteroaromatic ring compound, is particularly significant when two types of hosts with different carrier balances are mixed, as in this embodiment. This is because the recombination region spreads throughout the entire luminescent layer, and the exciton stabilization effect becomes pronounced.

[0474] From the above, it has been found that a light-emitting device according to one aspect of the present invention can be driven at a low voltage and provide a light-emitting device with high luminous efficiency and high reliability.

[0475] The configurations, structures, and methods shown in this embodiment can be used in appropriate combination with the configurations, structures, and methods shown in other embodiments and examples.

[0476] In this embodiment, light-emitting devices 2A to 2D, which are light-emitting devices according to one aspect of the present invention, are fabricated, and the results of measuring the characteristics of each device are described. A fluorescent light-emitting material was used for the light-emitting layer.

[0477] The structural formulas of the organic compounds used in light-emitting devices 2A to 2D are shown below.

[0478]

[0479] As shown in Figure 19, each light-emitting device has a sequential stacking structure in which a hole injection layer 911, a hole transport layer 912 (second hole transport layer 912_2 and first hole transport layer 912_1), a light-emitting layer 913, an electron transport layer 914 (first electron transport layer 914_1 and second electron transport layer 914_2), and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a glass substrate 900, and a second electrode 902 is stacked on the electron injection layer 915.

[0480] <Method for fabricating the light-emitting device 2A> A first electrode 901 was formed on a glass substrate 900 by sputtering indium tin oxide (ITSO) containing silicon oxide to a thickness of 110 nm as a transparent electrode. The electrode area was 4 mm². ２ (2 mm x 2 mm)

[0481] Next, as a pretreatment for forming the light-emitting device on the substrate, the substrate surface was washed with water and fired at 200°C for 1 hour. After that, 1 × 10 −４ The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus. After that, it was allowed to cool naturally.

[0482] Next, the substrate on which the first electrode 901 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 901 is formed faces downwards. N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBiF) and an electron acceptor material (OCHD-003) with a molecular weight of 672 and containing fluorine are co-deposited on the first electrode 901 in a weight ratio of 1:0.03 (= PCBiF:OCHD-003) and with a film thickness of 10 nm to form a hole injection layer 911.

[0483] Next, a second hole transport layer 912_2 was formed on the hole injection layer 911 by depositing PCBiF to a thickness of 90 nm. Then, a first hole transport layer 912_1 was formed by depositing N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP) to a thickness of 10 nm.

[0484] Next, on the first hole transport layer 912_1, 1-[10-(phenyl-2,3,4,5,6-d5)-9-anthryl]benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02-d5), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene-1,2,3,4,5,6,7,8-d8 (abbreviation: αN-βNPanth-d8), and N,N'-diphenyl-N,N'-bi Su(9-phenyl-9H-carbazole-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02) was co-deposited with Bnf(II)PhA-02-d5:αN-βNPAnth-d8:3,10PCA2Nbf(IV)-02 in a weight ratio of 0.5:0.5:0.015 (=Bnf(II)PhA-02-d5:αN-βNPAnth-d8:3,10PCA2Nbf(IV)-02) and with a film thickness of 25 nm to form an emissive layer 913.

[0485] Next, a first electron transport layer 914_1 was formed on the light-emitting layer 913 by depositing 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTZn) to a thickness of 10 nm. Subsequently, a second electron transport layer 914_2 was formed by depositing 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as mPPhen2P) to a thickness of 15 nm.

[0486] Next, lithium fluoride (LiF) was deposited onto the second electron transport layer 914_2 to a thickness of 1 nm to form an electron injection layer 915.

[0487] Next, a second electrode 902 was formed by depositing aluminum (Al) onto the electron injection layer 915 to a thickness of 150 nm, thereby fabricating the light-emitting device 2A.

[0488] <Method for fabricating light-emitting device 2B> Light-emitting device 2B differs from light-emitting device 2A in the configuration of the light-emitting layer 913. Specifically, in light-emitting device 2A, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with 1-(10-phenyl-9-antlyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02). The other components were fabricated in the same manner as light-emitting device 2A.

[0489] <Method for fabricating light-emitting device 2C> Light-emitting device 2C differs from light-emitting device 2A in the configuration of the light-emitting layer 913. Specifically, in light-emitting device 2A, αN-βNPanth-d8 used as the second host in the light-emitting layer 913 was replaced with 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPanth). The other components were fabricated in the same manner as light-emitting device 2A.

[0490] <Method for fabricating light-emitting device 2D> Light-emitting device 2D differs from light-emitting device 2C in the configuration of the light-emitting layer 913. Specifically, in light-emitting device 2A, Bnf(II)PhA-02-d5 used as the first host in the light-emitting layer 913 was replaced with 1-(10-phenyl-9-antlyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA-02). The other components were fabricated in the same manner as light-emitting device 2C.

[0491] The light-emitting device structures of light-emitting devices 2A to 2D are summarized in Table 6 below. Condition 2X is shown in Appendix Table 7.

[0492]

[0493]

[0494] <Light-emitting device characteristics> The above light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the characteristics of the light-emitting device were measured.

[0495] Figure 28 shows the luminance-current density characteristics of each light-emitting device, Figure 29 shows the luminance-voltage characteristics, Figure 30 shows the current efficiency-luminance characteristics, Figure 31 shows the current density-voltage characteristics, Figure 32 shows the power efficiency-luminance characteristics, Figure 33 shows the external quantum efficiency-luminance characteristics, and Figure 34 shows the field emission spectra.

[0496] Furthermore, the brightness of each light-emitting device is 1000 cd / m². ２ Table 8 below shows the main characteristics in the vicinity. A spectroradiometer (Topcon SR-UL1R) was used to measure luminance, CIE chromaticity, and emission spectrum. Power efficiency and external quantum efficiency were calculated using luminance and emission spectrum measured from the front of the substrate's light-emitting surface with a spectroradiometer, assuming a Lambertsian light distribution pattern.

[0497]

[0498] From Figure 34 and Table 8 above, it became clear that light-emitting devices 2A to 2D are light-emitting devices with good characteristics, exhibiting blue light emission derived from 3,10PCA2Nbf(IV)-02. Furthermore, from Figures 28 to 34 and Table 8 above, it became clear that light-emitting devices 2A to 2C exhibit performance equivalent to that of the comparative light-emitting device 2D.

[0499] This is because a heteroaromatic ring compound was used as the first host and a hydrocarbon compound was used as the second host, resulting in devices with low driving voltage, low power consumption, and high luminous efficiency in both types of light-emitting elements. This is thought to be because the devices using a heteroaromatic ring compound as the first host and a hydrocarbon compound as the second host exhibited improved carrier implantation, transport, or both. Furthermore, it is believed that the improved carrier implantation or transport also led to an improved carrier balance, resulting in good luminous efficiency.

[0500] From the above results, it was found that the light-emitting device according to one aspect of the present invention is a light-emitting device with high luminous efficiency (power efficiency, current efficiency, and external quantum efficiency) and low driving voltage.

[0501] <Reliability Test Results> Furthermore, reliability tests were conducted on light-emitting devices 2A to 2D. Constant current density (50 [mA / cm²] ２ Figure 35 shows the time variation of the normalized brightness during operation. In Figure 35, the vertical axis represents the brightness (%) normalized with the brightness at the start of operation of the element set to 100%, and the horizontal axis represents the operation time (h) of the element.

[0502] Figure 35 shows that the LT95(h) values, which represent the elapsed time until the measured brightness decreases to 95% of the initial brightness, were 166 hours for light-emitting device 2A, 80 hours for light-emitting device 2B, 137 hours for light-emitting device 2C, and 59 hours for light-emitting device 2D. Light-emitting devices 2A to 1C were found to exhibit reliability more than three times better than the comparative light-emitting device 2D. This is thought to be because the deuterization of the host stabilized the excited state host material generated by the recombination of carriers in the light-emitting layer host material, thereby suppressing degradation. In particular, by using a heteroaromatic ring compound for the first host and a hydrocarbon compound for the second host, the carrier implantability, or transportability, or both, improved, and the carrier balance of the entire device improved, resulting in a remarkable effect of suppressing the degradation of the light-emitting layer host material. It can be said that a synergistic effect was obtained by deuterizing each of the mixed hosts.

[0503] In particular, it was found that light-emitting devices 2A and 2C, which used the deuterated first host, exhibited reliability more than 2.5 times better than the comparative light-emitting device 2D. This result indicates that a greater reliability improvement can be obtained by deuterating the heteroaromatic ring compound, which is the first host. In other words, it was found that deuterating an organic compound having a heteroaromatic ring (the first host), which is thought to have higher hole transportability compared to the hydrocarbon compound, which is the second host, is more effective in extending the lifespan of the device. The heteroaromatic ring compound, which is the first host, plays a role in injecting and transporting holes into the entire light-emitting layer. On the other hand, the excited state of the organic compound having a heteroaromatic ring (the first host) is more prone to instability than the hydrocarbon compound, which is the second host, because it has a carbon-heteroatom bond. Therefore, it is thought that a significant reliability improvement can be obtained by deuterating an organic compound having a heteroaromatic ring (the first host), which is thought to have higher hole transportability compared to the hydrocarbon compound, which is the second host. Furthermore, the effect of deuterating the first host, the heteroaromatic ring compound, is particularly significant when two types of hosts with different carrier balances are mixed, as in this embodiment. This is because the recombination region spreads throughout the entire luminescent layer, and the exciton stabilization effect becomes pronounced.

[0504] Furthermore, Example 2 differs from Example 1 in the material used for the first electron transport layer 914_1. The device in Example 2 using mFBPTZn for the first electron transport layer 914_1 is considered to have a device structure that provides higher electron injection and transport properties compared to the device in Example 1 using 2mPCCzPDBq for the first electron transport layer 914_1. By comparing Example 1 and Example 2, it was found that the effect of deuterizing the light-emitting layer host is that the higher the electron injection and transport properties of the first electron transport layer 914_1, the more significantly improved the reliability.

[0505] From the above, it has been found that a light-emitting device according to one aspect of the present invention can be driven at a low voltage and provide a light-emitting device with high luminous efficiency and high reliability.

[0506] The configurations, structures, and methods shown in this embodiment can be used in appropriate combination with the configurations, structures, and methods shown in other embodiments and examples.

[0507] 100: Display device, 100A: Display device, 100B: Display device, 100C: Display device, 100D: Display device, 100E: Display device, 101: First electrode, 101W: First electrode, 102: Second electrode, 103: Organic compound layer, 103a: Organic compound layer, 103B: Organic compound layer, 103b: Organic compound layer, 103c: Organic compound layer, 103G: Organic compound layer, 103R: Organic compound layer, 104: Common layer, 106: Charge generation layer, 106a: Charge generation layer, 106b: Charge generation layer, 110: Sub-pixel, 110B: Sub-pixel, 110G: Sub-pixel, 110Gw: Width, 1 10R: Sub-pixel, 110Rw: Width, 110W: Sub-pixel, 111: Hole injection layer, 112: Hole transport layer, 112B: Conductive layer, 112R: Conductive layer, 113: Light-emitting layer, 113a: Light-emitting layer, 113b: Light-emitting layer, 113c: Light-emitting layer, 114: Electron transport layer, 115: Electron injection layer, 118: Host material, 118_1: Organic compound, 118_2: Organic compound, 119: Guest material, 120: Substrate, 122: Resin layer, 124a: Pixel, 124b: Pixel, 125: Inorganic insulating layer, 126B: Conductive layer, 126R: Conductive layer, 127: Insulating layer, 128: Layer, 129B: Conductive layer, 129R: Conductive layer, 130: Light-emitting device, 130B: Light-emitting device, 130G: Light-emitting device, 130R: Light-emitting device, 131: Protective layer, 132B: Colored layer, 132G: Colored layer, 132R: Colored layer, 140: Connection part, 141: Region, 142: Adhesive layer, 143: Planarization film, 144: Planarization film, 151: Conductive layer, 151B: Conductive layer, 151C: Conductive layer, 151G: Conductive layer, 151R: Conductive layer, 152: Conductive layer, 152B: Conductive layer, 152C: Conductive layer, 152G: Conductive layer, 152R: Conductive layer, 153: Insulating layer, 155: Common electrode, 156: Insulating layer, 156B: Insulating layer , 156C: insulating layer, 156G: insulating layer, 156R: insulating layer, 157: light-shielding layer, 158B: sacrificial layer, 158G: sacrificial layer, 158R: sacrificial layer, 166: conductive layer, 171: insulating layer, 172: conductive layer, 173: insulating layer, 174: insulating layer, 175: insulating layer, 176: plug, 177: pixel part, 178: pixel, 178a: pixel, 178b: pixel, 180: organic resin layer, 181: recess, 181a: recess, 181b: recess, 181c: recess, 182: microlens, 201: transistor, 204: connection part, 205: transistor, 211: insulating layer, 213: insulating layer,214: insulating layer, 215: insulating layer, 221: conductive layer, 222a: conductive layer, 222b: conductive layer, 223: conductive layer, 224B: conductive layer, 224C: conductive layer, 224G: conductive layer, 224R: conductive layer, 231: semiconductor layer, 240: capacitance, 241: conductive layer, 242: connection layer, 243: insulating layer, 245: conductive layer, 254: insulating layer, 255: insulating layer, 256: plug, 261: insulating layer, 271: plug, 280: display module, 281: display unit, 282: circuit unit, 283: pixel circuit unit, 283a: pixel circuit, 284: pixel unit, 284a: pixel, 285: terminal unit, 28 6: Wiring section, 290: FPC, 291: Substrate, 292: Substrate, 301: Substrate, 310: Transistor, 311: Conductive layer, 312: Low-resistance region, 313: Insulating layer, 314: Insulating layer, 315: Element isolation layer, 317: Light-shielding layer, 351: Substrate, 352: Substrate, 353: FPC, 354: IC, 355: Wiring, 356: Circuit, 700A: Electronic equipment, 700B: Electronic equipment, 721: Housing, 723: Mounting section, 727: Earphone section, 750: Earphone, 751: Display panel, 753: Optical component, 756: Display area, 757: Frame, 758: Nose pad, 800A: Electric Sub-device, 800B: Electronic equipment, 820: Display unit, 821: Housing, 822: Communication unit, 823: Mounting unit, 824: Control unit, 825: Imaging unit, 827: Earphone unit, 832: Lens, 900: Glass substrate, 901: First electrode, 902: Second electrode, 911: Hole injection layer, 912: Hole transport layer, 912_1: First hole transport layer, 912_2: Second hole transport layer, 913: Light-emitting layer, 914: Electron transport layer, 914_1: First electron transport layer, 914_2: Second electron transport layer, 915: Electron injection layer, 6500: Electronic equipment, 6501: Housing, 6502: Display unit, 650 3: Power button, 6504: Button, 6505: Speaker, 6506: Microphone, 6507: Camera, 6508: Light source, 6510: Protective component, 6511: Display panel, 6512: Optical component, 6513: Touch sensor panel, 6515: FPC, 6516: IC, 6517: Printed circuit board, 6518: Battery, 7000: Display unit, 7100: Television equipment, 7151: Remote control unit, 7171: Enclosure, 7173: Stand, 7200: Notebook personal computer, 7211: Enclosure, 7212: Keyboard, 7213: Pointing device7214: External connection port, 7300: Digital signage, 7301: Enclosure, 7303: Speaker, 7311: Information terminal, 7400: Digital signage, 7401: Pillar, 7411: Information terminal, 9000: Enclosure, 9001: Display unit, 9002: Camera, 9003: Speaker, 9005: Operation keys, 9006: Connection terminal, 9007: Sensor, 9008: Microphone, 9050: Icon, 9051: Information, 9052: Information, 9053: Information, 9054: Information, 9055: Hinge, 9171: Portable information terminal, 9172: Portable information terminal, 9173: Tablet terminal, 9200: Portable information terminal, 9201: Portable information terminal,

Claims

A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a fluorescent light-emitting material. A light-emitting device in which one or both of the first organic compound and the second organic compound have one or more deuterium atoms. 　 A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a fluorescent light-emitting material. The first organic compound is an organic compound having a heteroaromatic ring, A light-emitting device in which one or both of the first organic compound and the second organic compound have one or more deuterium atoms. 　 A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The second organic compound is an aromatic compound consisting of aromatic hydrocarbons, A light-emitting device having one or more deuterium atoms, wherein one or both of the first organic compound and / or the second organic compound. 　 A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is an organic compound having a heteroaromatic ring, The second organic compound is an aromatic compound consisting of aromatic hydrocarbons, A light-emitting device in which one or both of the first organic compound and the second organic compound have one or more deuterium atoms. 　 In either claim 3 or claim 4, The aforementioned light-emitting material is a fluorescent light-emitting material in the light-emitting device. 　 In any one of claims 1 to 4, The first organic compound and the second organic compound are light-emitting devices having one or more deuterium atoms. 　 In any one of claims 1 to 4, A light-emitting device in which either the first organic compound or the second compound has an anthracene skeleton in its molecular structure. 　 In any one of claims 1 to 4, The first organic compound and the second compound are light-emitting devices having an anthracene skeleton in their molecular structure. 　 A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is an organic compound having a heteroaromatic ring containing anthracene, The second organic compound is an organic compound having a heteroaromatic ring containing anthracene, The first organic compound and the second organic compound have different molecular structures. A light-emitting device in which one or both of the first organic compound and the second organic compound have one or more deuterium atoms. 　 A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is an aromatic compound consisting of an aromatic hydrocarbon having anthracene, The second organic compound is an aromatic compound consisting of an aromatic hydrocarbon having anthracene, The first organic compound and the second organic compound have different molecular structures. A light-emitting device in which one or both of the first organic compound and the second organic compound have one or more deuterium atoms. 　 A light-emitting layer is provided between a pair of electrodes. The light-emitting layer comprises a first organic compound, a second organic compound, and a light-emitting substance. The first organic compound is represented by the following general formula (G1), The second organic compound is represented by the following general formula (G2): A light-emitting device in which one or both of the first organic compound and the second organic compound have one or more deuterium atoms. (wherein, R １ to R ８ each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, or a cyano group, Ar １ and Ar ２ each independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms, Ar ３ and Ar ４ each independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, Ar ３ and Ar ４ one of which is a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. n and m each independently represent an integer of 0 or 1 to 4.) (In the formula, R １１ to R １８ each independently represents hydrogen (including deuterium), a linear or branched alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a cyano group, Ar １１ and Ar １２ each independently represents a substituted or unsubstituted arylene group having 6 to 30 carbon atoms, Ar １３ and Ar １４ each independently represents a substituted or unsubstituted aryl group having 6 to 30 carbon atoms. p and q each independently represent an integer of 0 or 1 to 4.)

Images