Light emitting device

Abstract

A light-emitting device with high emission efficiency is provided. A highly reliable light-emitting device is provided. A display device with high emission efficiency and high reliability is provided.SOLUTION: A first electrode, a second electrode, a light-emitting layer located between the first electrode and the second electrode, and a cap layer, wherein the second electrode is located between the light-emitting layer and the cap layer, the cap layer includes at least a first material and a second material, and the first material and the second material are materials having a difference of 0.1 or more in an ordinary ray refractive index at a wavelength of any one of 380 nm to 760 nm in respective vapor-deposited films; The first substance is a monoamine compound including an alkyl group, and the second substance is an organic compound including a carbazole skeleton.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] One embodiment of the present invention relates to an organic compound, an organic semiconductor element, a light-emitting device, a photodiode sensor, a display module, a lighting module, a display device, an electronic device, a lighting device, and an electronic device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification etc. relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, lighting devices, power storage devices, memory devices, imaging devices, driving methods thereof, and manufacturing methods thereof. [Background technology]

[0002] Light-emitting devices (also called organic EL elements) that utilize electroluminescence (EL) using organic compounds are becoming more and more common. The basic structure of these light-emitting devices is a pair of electrodes sandwiching an organic compound layer containing a light-emitting material. By applying a voltage to this device, carriers are injected, and the recombination energy of these carriers is utilized to emit light from the light-emitting material.

[0003] Since light-emitting devices are self-luminous, display devices using these light-emitting devices as pixels have higher visibility than liquid crystal display devices and do not require backlighting. Another major advantage of display devices using such light-emitting devices is that they can be fabricated to be thin and lightweight. Another feature is their extremely fast response speed.

[0004] Furthermore, these light-emitting devices can emit light in a planar, continuous pattern because the light-emitting layer can be formed continuously in a planar pattern. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs and LEDs, or linear light sources such as fluorescent lamps, making them highly useful as surface light sources for lighting applications.

[0005] Display devices and lighting devices using such light-emitting devices are suitable for a variety of electronic devices, but research and development is ongoing to find light-emitting devices with even better characteristics.

[0006] Patent Document 1 discloses a light-emitting device using organic electroluminescence having a capping layer that can improve light extraction efficiency. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-092485 Summary of the Invention [Problem to be solved by the invention]

[0008] An object of one embodiment of the present invention is to provide a novel light-emitting device.An object of one embodiment of the present invention is to provide a light-emitting device with good characteristics.Another object of one embodiment of the present invention is to provide a light-emitting device with good reliability.Another object of one embodiment of the present invention is to provide a light-emitting device with high luminous efficiency.Another object of one embodiment of the present invention is to provide a light-emitting device with good reliability and high luminous efficiency.

[0009] Another object of one embodiment of the present invention is to provide a display device with favorable characteristics.Another object of one embodiment of the present invention is to provide a display device with favorable reliability.Another object of one embodiment of the present invention is to provide a display device with low power consumption.Another object of one embodiment of the present invention is to provide a light-emitting device with favorable reliability and low power consumption.

[0010] Another object of one embodiment of the present invention is to provide either an electronic device or a lighting device with high reliability, or an electronic device or a lighting device with low power consumption.

[0011] The present invention is intended to solve any one of the above-mentioned problems. Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent 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. [Means for solving the problem]

[0012] One embodiment of the present invention is a light-emitting device comprising a first electrode, a second electrode, a light-emitting layer located between the first electrode and the second electrode, and a capping layer, wherein the second electrode is located between the light-emitting layer and the capping layer, and the capping layer comprises at least a first substance and a second substance, the first substance and the second substance being substances whose ordinary refractive indices at any wavelength from 380 nm to 760 nm in their respective evaporated films differ by 0.1 or more, and the first substance is a monoamine compound containing an alkyl group, and the second substance is an organic compound containing a carbazole skeleton.

[0013] Alternatively, another embodiment of the present invention is a light-emitting device comprising: a first electrode, a second electrode, a light-emitting layer located between the first electrode and the second electrode; and a capping layer. The second electrode is located between the light-emitting layer and the capping layer. The capping layer comprises a first layer containing at least a first substance and a second layer containing a second substance. The first substance and the second substance have ordinary refractive indices at any wavelength from 380 nm to 760 nm that differ by 0.1 or more in their evaporated films. The first substance is a monoamine compound containing an alkyl group, and the second substance is an organic compound containing a carbazole skeleton.

[0014] Alternatively, another embodiment of the present invention is a light-emitting device comprising: a first electrode, a second electrode, a light-emitting layer located between the first electrode and the second electrode; and a capping layer. The second electrode is located between the light-emitting layer and the capping layer. The capping layer comprises a first layer containing at least a second substance and a second layer containing the first substance. The first layer is located between the second electrode and the second layer. The first substance and the second substance have ordinary refractive indices at any wavelength from 380 nm to 760 nm that differ by 0.1 or more in their evaporated films. The first substance is a monoamine compound containing an alkyl group, and the second substance is an organic compound containing a carbazole skeleton.

[0015] Alternatively, another embodiment of the present invention is a light-emitting device comprising: a first electrode, a second electrode, a light-emitting layer located between the first electrode and the second electrode; and a capping layer. The second electrode is located between the light-emitting layer and the capping layer. The capping layer comprises a first layer containing at least a first substance and a second layer containing a second substance. The first layer is in contact with the second electrode. The first substance and the second substance have ordinary refractive indices at any wavelength from 380 nm to 760 nm that differ by 0.1 or more in their evaporated films. The first substance is a monoamine compound containing an alkyl group, and the second substance is an organic compound containing a carbazole skeleton.

[0016] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first substance and the second substance are substances whose refractive indices of ordinary light in the respective evaporated films at any wavelength from 380 nm to 760 nm differ by 0.3 or more.

[0017] Another embodiment of the present invention is a light-emitting device having any of the above structures, which includes a monoamine compound having no trifluoromethyl group.

[0018] Alternatively, another embodiment of the present invention is a compound having the above structure, wherein the monoamine compound is represented by the following general formula (G L 1) is an organic compound light-emitting device.

[0019] [ka]

[0020] However, the general formula (G L In the organic compound represented by 1), Ar 1 ~Ar 3 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 4 ~Ar 6 Each of n, m, and l independently represents any one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and each of n, m, and l independently represents any one of integers from 0 to 3. Note that when any one or more of n, m, and l is 2 or more, multiple Ar 1 , multiple Ar 2 , multiple Ar 3 may be the same or different. L The organic compound represented by the general formula (G 1) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms. L All hydrogen atoms in the organic compound represented by 1) may be deuterium atoms independently of each other.

[0021] Alternatively, in the above structure, another embodiment of the present invention is a compound represented by the following general formula (G H 1) is an organic compound light-emitting device.

[0022] [ka]

[0023] However, the general formula (G H In the organic compound represented by 1), R 11 ~R 18 each independently represents hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms; R 19 represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms. All hydrogen atoms may be replaced by deuterium, and the aromatic hydrocarbon group and heteroaromatic group may have a structure in which multiple rings are bonded to each other. When the group is composed of multiple rings, there may be multiple aromatic hydrocarbon groups, multiple heteroaromatic groups, or both an aromatic hydrocarbon group and a heteroaromatic group.

[0024] Alternatively, another embodiment of the present invention is a compound having the above structure, wherein the monoamine compound is represented by the following general formula (G L 1), and the organic compound containing a carbazole skeleton is represented by the following general formula (G H 1) is an organic compound light-emitting device.

[0025] [ka]

[0026] General formula (G L In the organic compound represented by 1), Ar 1 ~Ar 3 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 4 ~Ar 6 Each of n, m, and l independently represents any one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and each of n, m, and l independently represents any one of integers from 0 to 3. Note that when any one or more of n, m, and l is 2 or more, multiple Ar 1 , multiple Ar 2 , multiple Ar 3 may be the same or different. L The organic compound represented by the general formula (G 1) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms. L All hydrogen atoms in the organic compound represented by 1) may be deuterium atoms independently of each other.

[0027] In addition, the general formula (G H In the organic compound represented by 1), R 11 ~R 18 each independently represents hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms; R 19represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms. All hydrogen atoms may be replaced by deuterium, and the aromatic hydrocarbon group and heteroaromatic group may have a structure in which multiple rings are bonded to each other. When the group is composed of multiple rings, there may be multiple aromatic hydrocarbon groups, multiple heteroaromatic groups, or both an aromatic hydrocarbon group and a heteroaromatic group.

[0028] Alternatively, another embodiment of the present invention is a light-emitting device having the above-described structure, wherein the evaporated film of the first substance has an ordinary refractive index of 1.70 or less at 450 nm, and the evaporated film of the second substance has an ordinary refractive index of 1.80 or more at 450 nm.

[0029] Alternatively, another embodiment of the present invention is a light-emitting device having the above-described structure, wherein the evaporated film of the first substance has an ordinary refractive index of 1.70 or less at 450 nm, and the evaporated film of the second substance has an ordinary refractive index of 2.00 or more at 450 nm.

[0030] Another embodiment of the present invention is a display device including any of the above light-emitting devices.

[0031] Another embodiment of the present invention is an electronic device including any of the above light-emitting devices and a sensor, an operation button, a speaker, or a microphone.

[0032] Another embodiment of the present invention is a lighting device including the above-described light-emitting device and a housing. [Effects of the Invention]

[0033] According to one embodiment of the present invention, a novel light-emitting device can be provided. A light-emitting device with favorable characteristics can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable reliability can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with high emission efficiency can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable reliability and high emission efficiency can be provided.

[0034] Alternatively, one embodiment of the present invention can provide a display device with favorable characteristics. Alternatively, one embodiment of the present invention can provide a display device with favorable reliability. Alternatively, one embodiment of the present invention can provide a display device with low power consumption. Alternatively, one embodiment of the present invention can provide a light-emitting device with favorable reliability and low power consumption.

[0035] Alternatively, one embodiment of the present invention can provide either an electronic device or a lighting device with high reliability, or an electronic device or a lighting device with low power consumption.

[0036] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract other effects from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0037] [Figure 1] 1A to 1C are schematic diagrams of a light-emitting device according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of a light-emitting device according to one embodiment of the present invention. [Figure 3] 3A and 3B illustrate a display device according to one embodiment of the present invention. [Figure 4]4A and 4B illustrate a display device according to one embodiment of the present invention. [Figure 5] 5A to 5E are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 6] 6A and 6B are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 7] 7A to 7D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 8] 8A to 8C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 9] 9A to 9C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 10] 10A to 10C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 11] 11(A) and 11(B) are perspective views showing configuration examples of a display module. [Figure 12] 12(A) and 12(B) are cross-sectional views showing examples of the configuration of a display device. [Figure 13] FIG. 13 is a perspective view showing a configuration example of a display device. [Figure 14] FIG. 14 is a cross-sectional view showing an example of the configuration of a display device. [Figure 15] FIG. 15 is a cross-sectional view showing an example of the configuration of a display device. [Figure 16] 16A to 16C are diagrams showing configuration examples of display devices. [Figure 17] FIG. 17 is a cross-sectional view showing an example of the configuration of a display device. [Figure 18] 18A to 18C are diagrams showing configuration examples of display devices. [Figure 19] 19A to 19D are diagrams showing examples of electronic devices. [Figure 20] 20A to 20F are diagrams showing examples of electronic devices. [Figure 21]21A to 21G are diagrams showing examples of electronic devices. [Figure 22] FIG. 22 is a diagram showing the refractive indexes of mmtBumTPoFBi-02 and PCP(βN2). [Figure 23] FIG. 23 is a graph showing the luminance-current density characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 24] FIG. 24 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 1 and the comparative light-emitting device 1. In FIG. [Figure 25] FIG. 25 is a graph showing the luminance-voltage characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 26] FIG. 26 is a graph showing the current density-voltage characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 27] FIG. 27 is a graph showing the blue index-current density characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Device 1. As shown in FIG. [Figure 28] FIG. 28 shows the electroluminescence spectra of Light-Emitting Device 1 and Comparative Light-Emitting Device 1. As shown in FIG. [Figure 29] FIG. 29 shows reflected bright field images of Samples 1 to 3 taken by an optical microscope after the high-temperature storage test. [Figure 30] FIG. 30 is a graph showing the blue index-current density characteristics of Sample 1. [Figure 31] FIG. 31 is a graph showing the blue index-current density characteristics of Sample 2. [Figure 32] FIG. 32 is a graph showing the blue index-current density characteristics of Sample 3. DETAILED DESCRIPTION OF THE INVENTION

[0038] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0039] Furthermore, in this specification, ordinal numbers such as "first" and "second" are used to avoid confusion among constituent elements, and do not limit the number of constituent elements or the order of the constituent elements (for example, the order of processes or the order of stacking). Furthermore, even if a term does not have an ordinal number in this specification, ordinal numbers may be added in the claims to avoid confusion among the constituent elements. Even if a term has an ordinal number in this specification, ordinal numbers may be added in the claims. Even if a term has an ordinal number in this specification, ordinal numbers may be omitted in the claims.

[0040] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0041] Furthermore, when light is incident on a material with optical anisotropy, the light in the vibration plane parallel to the optical axis is called extraordinary light (ray), and the light in the vibration plane perpendicular to the optical axis is called ordinary light (ray). However, the refractive index of the material for ordinary light and the refractive index for extraordinary light may differ. In such cases, anisotropy analysis can be performed to separate the ordinary refractive index and the extraordinary refractive index and calculate each refractive index. In this specification, if the measured material has both an ordinary refractive index and an extraordinary refractive index, the ordinary refractive index will be used as the index.

[0042] Similarly to the refractive index, the extinction coefficient may also differ between ordinary and extraordinary light, and by performing anisotropy analysis, it is possible to separate the ordinary and extraordinary light extinction coefficients and calculate each extinction coefficient separately. In this specification, if the measured material has both an ordinary light extinction coefficient and an extraordinary light extinction coefficient, the ordinary light extinction coefficient will be used as the index.

[0043] In addition, the vapor-deposited film in this specification refers to a film formed by vapor deposition on a substrate at room temperature.

[0044] In this specification and the like, a photoluminescence (PL) spectrum refers to a spectrum obtained in fluorometry by fixing the excitation wavelength of excitation light and measuring the wavelength of emitted light. It may also be called an emission spectrum. The emission spectrum may contain fluorescent components and phosphorescent components. In this specification and the like, an emission spectrum consisting of fluorescent components may be particularly called a fluorescence spectrum, and an emission spectrum consisting of phosphorescent components may be particularly called a phosphorescent spectrum.

[0045] (Embodiment 1) 1A to 1C illustrate a light-emitting device 600 according to one embodiment of the present invention. The light-emitting device illustrated in FIG. 1 includes a first electrode 101, a second electrode 102, an organic compound layer 103, and a cap layer 155. The organic compound layer 103 includes at least a light-emitting layer 113.

[0046] 1A to 1C is a so-called top-emission light-emitting device that emits light from the second electrode 102 side. Note that the light-emitting device of one embodiment of the present invention may be a dual-emission light-emitting device that emits light from both the first electrode 101 and the second electrode 102.

[0047] The second electrode 102 is provided in contact with the organic compound layer 103 and the cap layer 155, and is sandwiched between the organic compound layer 103 and the cap layer 155. By providing the cap layer 155 on the second electrode 102, the light extraction efficiency can be improved.

[0048] The cap layer 155 is a layer including at least a first substance and a second substance. The first substance is a monoamine compound including an alkyl group, and the second substance is an organic compound including a carbazole skeleton.

[0049] The inclusion of the first material and the second material in the capping layer 155 improves heat resistance, allowing a vapor-deposited film of good film quality to be used as the capping layer. This allows a highly stable capping layer to be formed, making it possible to provide a highly reliable light-emitting device. This allows for the provision of a highly reliable device in environments requiring high-temperature operation or high-temperature storage.

[0050] It is preferable that the plurality of substances contained in the cap layer 155 are all organic compounds, because the cap layer can be formed by vacuum deposition continuously after the electrode film formation.

[0051] The capping layer 155 preferably includes a first layer containing a first substance and a second layer containing a second substance. The monoamine compound containing an alkyl group, which is the first substance contained in the first layer, can easily be made into an organic compound with a low refractive index. The organic compound containing a carbazole skeleton, which is the second substance contained in the second layer, can easily be made into an organic compound with a high refractive index. Therefore, the refractive indices of the first layer and the second layer can be made to differ significantly. Specifically, the ordinary refractive indices of the first layer and the second layer at wavelengths between 380 nm and 760 nm can easily be made to differ by 0.1 or more, preferably 0.3 or more. This can further improve the light extraction efficiency of the light-emitting device.

[0052] Furthermore, since the first layer contains the first substance and the second layer contains the second substance, the ordinary refractive index of the first layer is likely to be lower than that of the second layer. Therefore, a structure in which the first layer is located between the second electrode and the second layer is preferable because it significantly improves the light extraction efficiency. That is, the cap layer 155 preferably has a stacked structure as shown in FIG. 1B because it can further improve the light extraction efficiency. Although FIG. 1B shows a two-layer stack of the first layer 188 and the second layer 189, a stacked structure with more layers may also be used.

[0053] The refractive index of the vapor-deposited film of the first material for light of a certain wavelength is preferably lower than the refractive index of the vapor-deposited film of the second material for light of the same wavelength. Specifically, the ordinary refractive index of the vapor-deposited film of the first material at any wavelength between 380 nm and 760 nm is preferably lower than the ordinary refractive index of the vapor-deposited film of the second material at the same wavelength. This difference is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more.

[0054] More specifically, it is preferable that the ordinary refractive index of the vapor-deposited film of the first substance at any wavelength of 380 nm or more and less than 500 nm is 1.80 or less, and that the ordinary refractive index of the vapor-deposited film of the second substance at any wavelength of 380 nm or more and less than 500 nm is 1.90 or more.It is even more preferable, in order to improve light extraction efficiency, that the ordinary refractive index of the vapor-deposited film of the first substance at any wavelength of 380 nm or more and less than 500 nm is 1.70 or less, and that the ordinary refractive index of the vapor-deposited film of the second substance at any wavelength of 380 nm or more and less than 500 nm is 2.00 or more.

[0055] Furthermore, it is preferable that the ordinary refractive index of the vapor-deposited film of the first substance at any wavelength of 500 nm or more and less than 600 nm is 1.72 or less, and that the ordinary refractive index of the vapor-deposited film of the second substance at any wavelength of 500 nm or more and less than 600 nm is 1.90 or more, and it is even more preferable for improving light extraction efficiency that the ordinary refractive index of the vapor-deposited film of the first substance at any wavelength of 500 nm or more and less than 600 nm is 1.68 or less, and that the ordinary refractive index of the vapor-deposited film of the second substance at any wavelength of 500 nm or more and less than 600 nm is 1.93 or more.

[0056] Furthermore, it is preferable that the ordinary refractive index of the vapor-deposited film of the first substance at any wavelength of 600 nm or more and 760 nm or less is 1.70 or less, and that the ordinary refractive index of the vapor-deposited film of the second substance at any wavelength of 600 nm or more and 760 nm or less is 1.80 or more, and it is even more preferable for improving light extraction efficiency that the ordinary refractive index of the vapor-deposited film of the first substance at any wavelength of 600 nm or more and 760 nm or less is 1.65 or less, and that the ordinary refractive index of the vapor-deposited film of the second substance at any wavelength of 600 nm or more and 760 nm or less is 1.85 or more.

[0057] In addition, it is preferable that the refractive index of the vapor-deposited film of the first substance at any wavelength of 380 nm or more and 760 nm or less is 1.40 or more, and it is more preferable that the refractive index of the vapor-deposited film of the second substance at any wavelength of 380 nm or more and 760 nm or less is 2.40 or less.

[0058] By stacking a layer containing a material with a low refractive index and a layer containing a material with a high refractive index, it becomes easier to extract light that is scattered within the light-emitting device, thereby improving the luminous efficiency of the light-emitting device. Note that, as described above, it is preferable that the first layer 188 be a layer with a low refractive index and the second layer 189 be a layer with a high refractive index, as this makes it easier to extract light.

[0059] The first substance, a monoamine compound containing an alkyl group, is an organic compound that can be easily deposited because its deposition temperature is relatively low. In other words, since it can be deposited at a low temperature, it can reduce the heat influence that other organic compounds used in light-emitting devices receive during deposition.

[0060] In particular, in mass production processes, the same material is heated continuously for long periods of time, and organic compounds that require high deposition temperatures are prone to decomposition. If the material decomposes, stable mass production becomes difficult. Therefore, organic compounds that can be deposited at low temperatures can be deposited without decomposition, making stable mass production possible.

[0061] In particular, by using a structure in which the first layer containing the first substance is located between the second electrode and the second layer, the first substance, which has a relatively low evaporation temperature, can be deposited first. Therefore, even if the evaporation temperature of the second substance is higher than that of the first substance, the influence of heat on the layer containing the organic compound can be reduced.

[0062] The monoamine compound having an alkyl group as the first substance is easy to vapor-deposit, has good and stable film quality, and can be made into a molecular structure with a short effective conjugation length, so it does not absorb visible light. Therefore, a light-emitting device using a monoamine compound having an alkyl group as the first substance is a light-emitting device that can be suitably used to provide a display device with good display quality. Furthermore, the light extraction efficiency can be improved, and the current load required to obtain high brightness can be reduced, resulting in a light-emitting device with good reliability.

[0063] The alkyl group-containing monoamine compound has an alkyl group, and therefore can be an organic compound having a smaller refractive index than one that does not have an alkyl group.

[0064] More specifically, the refractive index of ordinary light in a vapor-deposited film of a monoamine compound containing an alkyl group at any wavelength from 380 nm to 500 nm is preferably 1.80 or less, and more preferably 1.70 or less, in order to improve light extraction efficiency.

[0065] Furthermore, the refractive index of ordinary light in a vapor-deposited film of the alkyl-containing monoamine compound at any wavelength from 500 nm to 600 nm is preferably 1.72 or less, more preferably 1.68 or less, for improved light extraction efficiency.

[0066] Furthermore, the refractive index of ordinary light in a vapor-deposited film of the alkyl-containing monoamine compound at any wavelength from 600 nm to 760 nm is preferably 1.70 or less, more preferably 1.65 or less, for improved light extraction efficiency.

[0067] The refractive index of ordinary light in a vapor-deposited film of the alkyl-containing monoamine compound at any wavelength from 380 nm to 760 nm is preferably 1.40 or more.

[0068] The alkyl group in the alkyl-containing monoamine compound is preferably a cycloalkyl group or a branched alkyl group having 3 or more carbon atoms, since this reduces the refractive index. A cyclohexyl group or a tert-butyl group is more preferred, since it provides high heat resistance and stable film quality. Furthermore, the number of alkyl groups in the alkyl-containing monoamine compound is preferably 1 to 10, since this achieves both a low refractive index and high heat resistance and stable film quality. Furthermore, since the compound of the present application has hole transport properties due to its amine structure, it can also be used in the hole transport layer of an organic EL layer. In this case, the number of alkyl groups in the alkyl-containing monoamine compound is preferably 1 to 10, since this facilitates achieving both a low refractive index and carrier transport properties. Using the same material for the capping layer and the hole transport layer reduces the number of materials used in the organic EL device, which is preferable, as it leads to reduced manufacturing costs.

[0069] Furthermore, the amine compound having an alkyl group can be an organic compound with a high lowest unoccupied molecular orbital (LUMO) level. The capping layer is preferably formed in contact with the second electrode, which is often the cathode. Forming a substance with a low LUMO level on the cathode can adversely affect the characteristics due to interactions. Therefore, by using an amine compound having an alkyl group with a high LUMO level for the capping layer, particularly in a configuration in which the first layer containing the first substance is in contact with the second electrode, it is possible to suppress the interaction between the capping layer and the second electrode and provide a light-emitting device with excellent characteristics.

[0070] Furthermore, the monoamine compound containing an alkyl group preferably has an aryl group. The presence of an aryl group allows for the formation of a highly heat-resistant and stable film. Furthermore, as the aryl group, an aryl group having 6 to 30 carbon atoms is preferred because it has high heat resistance and can prevent decomposition due to excessively high deposition temperatures. A group having a fluorene skeleton is preferred for achieving highly heat-resistant and stable film quality. Examples of groups having a fluorene skeleton include a fluorenyl group, a dimethylfluorenyl group, a diphenylfluorenyl group, and a spirobifluorenyl group. Dimethylfluorenyl and diphenylfluorenyl groups are particularly preferred because they can achieve a low refractive index. The group having a fluorene skeleton is preferred because it is directly bonded to the nitrogen atom of the amine of the monoamine compound, thereby achieving both a low refractive index and highly heat-resistant and stable film quality.

[0071] Furthermore, the aryl group of the alkyl-containing monoamine compound is preferably a group having a biphenyl skeleton, since it provides a stable film with high heat resistance. Examples of the biphenyl skeleton group include o-biphenyl, m-biphenyl, p-biphenyl, and terphenyl groups. Among these, p-biphenyl and o-biphenyl groups are preferred because they provide high heat resistance and can prevent decomposition due to excessively high deposition temperatures. The o-biphenyl group is more preferred as a cap film for an organic EL device for obtaining visible light emission, since the absorption edge of the film of the alkyl-containing monoamine compound has a shorter wavelength than that of the p-biphenyl group.

[0072] Furthermore, as the aryl group contained in the monoamine compound having an alkyl group, a phenyl group is preferred because the deposition temperature does not become too high and the absorption edge of the film of the monoamine compound having an alkyl group is at a short wavelength, and a group containing a naphthalene skeleton is preferred because a stable film having high heat resistance can be obtained.

[0073] It is preferable that the monoamine compound containing an alkyl group has both a group having a fluorene skeleton and a group having a biphenyl skeleton, since this has both the effects of the biphenyl group and the effects of the fluorenyl group described above and does not cause the deposition temperature to become too high. In particular, a monoamine compound combining a biphenyl group and a fluorenyl group is preferable as a cap film because it can form a film with very high thermal stability. Furthermore, it is preferable that the alkyl group in the monoamine compound containing an alkyl group is bonded to these aryl groups.

[0074] Since fluorine atoms have a small atomic refraction, organic compounds containing fluorine atoms can be used as substances with a low refractive index. However, the effects of fluorine compounds that are difficult to decompose on the human body have been discussed, and international regulations are becoming stricter. Therefore, it is preferable that the monoamine compound containing the alkyl group does not have a group containing a fluorine atom, such as a trifluoromethyl group, and more preferably does not have a fluorine atom. Furthermore, monoamine compounds having a trifluoromethyl group may be at risk of decomposing the trifluoromethyl group during vapor deposition to generate hydrofluoric acid, which may corrode the chamber of the sublimation purification machine, which is a purification equipment, and the vapor deposition machine, which is a vapor deposition equipment. Furthermore, if hydrofluoric acid is generated during device fabrication, it may have an adverse effect on the wiring used in the device and on the reliability of the device, so it is preferable not to use them.

[0075] A monoamine compound containing an alkyl group is capable of forming a vapor-deposited film with good film quality, and therefore, the monoamine compound in one embodiment of the present invention is preferably a monoamine compound containing an alkyl group.

[0076] The monoamine compound containing an alkyl group according to one embodiment of the present invention may be a compound containing multiple monoamine skeletons. However, the multiple monoamine skeletons in the monoamine compound are bonded via carbon atoms having sp3 hybrid orbitals and are not conjugated with each other. Due to this structure, even if the compound contains multiple monoamine skeletons, the absorption edge of a film formed using the compound is short-wavelength and does not absorb in the visible light region. Therefore, the compound is suitable for use as a cap film in an organic electroluminescence (EL) device for emitting visible light. Furthermore, due to this structure, a stable film with high heat resistance can be formed even if the monoamine skeleton has a small molecular structure, making the compound preferable as a cap film.

[0077] The monoamine compound containing an alkyl group includes a compound represented by the following general formula (G L The organic compound represented by 1) is preferred.

[0078] [ka]

[0079] However, the general formula (G L In the organic compound represented by 1), Ar 1 ~Ar 3 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 4 ~Ar 6 each independently represents one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0080] In addition, the above general formula (G L In 1), n, m, and l each independently represent an integer of 0 to 3. When any one or more of n, m, and l is 2 or more, a plurality of Ar 1 , multiple Ar 2 , multiple Ar 3 may be the same or different.

[0081] In addition, the general formula (G L The organic compound represented by general formula (G 1) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms. A branched alkyl group having 3 to 10 carbon atoms or a cycloalkyl group having 6 to 10 carbon atoms is preferred, with a tert-butyl group or a cyclohexyl group being more preferred. Of these, a tert-butyl group is particularly preferred. L The number of alkyl groups in the organic compound represented by 1) is preferably 1 or more and 10 or less, since this makes it easier to achieve both a low refractive index and carrier transportability.

[0082] In addition, the general formula (G L All hydrogen atoms in the organic compound represented by 1) may be deuterium atoms independently of each other.

[0083] The alkyl group-containing monoamine compound is represented by the following general formula (G L The organic compound may have two to four partial structures represented by the formula (2), each of which is bonded to another partial structure via a carbon atom having an sp3 hybrid orbital. When the alkyl group-containing monoamine compound has such a structure, a cap layer having good heat resistance can be obtained.

[0084] [ka]

[0085] However, the general formula (G L In the partial structure represented by 2), Ar 1 ~Ar 3 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 4 ~Ar 6 each independently represents one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0086] In addition, the above general formula (G L In the partial structure represented by 2), n, m, and l each independently represent an integer of 0 to 3. When any one or more of n, m, and l is 2 or more, a plurality of Ar 1 , multiple Ar 2 , multiple Ar 3 may be the same or different.

[0087] In addition, the general formula (G LThe partial structure represented by general formula (G 2) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms, preferably branched alkyl groups having 3 to 10 carbon atoms or cycloalkyl groups having 6 to 10 carbon atoms, and more preferably a tert-butyl group or a cyclohexyl group. Among these, a tert-butyl group is particularly preferred. L The number of alkyl groups in the organic compound having the partial structure represented by 2) is preferably 1 or more and 20 or less, since this makes it easier to achieve both a low refractive index and carrier transportability.

[0088] In addition, the general formula (G L All hydrogen atoms in the organic compound having the partial structure represented by 2) may be deuterium atoms independently of each other.

[0089] In addition, the general formula (G L The organic compound having the partial structure represented by general formula (G 2) preferably has two or more of the partial structures, since this allows for the formation of a highly stable film. L The organic compound having the partial structure represented by the following general formula (G L 3) to the following general formula (G L 5) is preferably an organic compound represented by the formula:

[0090] [ka]

[0091] However, the general formula (G L In the organic compound represented by 3), Ar 1 ~Ar 3 and Ar 11 ~Ar 13 are each independently one of a substituted or unsubstituted arylene group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms; Ar 4 ~Ar 6 and Ar 14 ~Ar 16each independently represents one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0092] In addition, the above general formula (G L In the organic compound represented by formula 3), n, m, l, p, q, and r each independently represent an integer of 0 to 3. When any one or more of n, m, l, p, q, and r is 2 or more, a plurality of Ar 1 , multiple Ar 2 , multiple Ar 3 , multiple Ar 11 , multiple Ar 12 , multiple Ar 13 may be the same or different.

[0093] In addition, the above general formula (G L In the organic compound represented by 3), R 1 and R 2 each independently represents an alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted phenyl group; R 1 and R 2 may be bonded to each other to form a ring.

[0094] In addition, the general formula (G L The organic compound represented by general formula (G 3) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms, preferably branched alkyl groups having 3 to 10 carbon atoms or cycloalkyl groups having 6 to 10 carbon atoms, and more preferably tert-butyl or cyclohexyl groups. Among these, tert-butyl groups are particularly preferred in order to obtain a compound with high sublimability. L The number of alkyl groups in the organic compound represented by general formula (G 3) is preferably 1 to 20, since this allows for both a low refractive index and a stable film quality with high heat resistance. L The organic compound represented by general formula (G 3) has an amine structure and therefore has hole transport properties, and can therefore also be used in the hole transport layer of the organic EL layer.L The number of alkyl groups in the organic compound represented by 3) is preferably 1 or more and 10 or less, since this makes it easier to achieve both a low refractive index and carrier transportability.

[0095] In addition, the general formula (G L All hydrogen atoms in the organic compound represented by 3) may be deuterium atoms independently of each other.

[0096] [ka]

[0097] However, the general formula (G L In the organic compound represented by 4), Ar 1 ~Ar 3 , Ar 11 ~Ar 13 and Ar 21 ~Ar 23 are each independently one of a substituted or unsubstituted arylene group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms; Ar 4 ~Ar 6 , Ar 14 ~Ar 16 and Ar 24 ~Ar 26 each independently represents one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0098] In addition, the above general formula (G L In the organic compound represented by formula 4), n, m, l, p, q, r, s, t, and u each independently represent an integer of 0 to 3. When any one or more of n, m, l, p, q, r, s, t, and u is 2 or more, a plurality of Ar 1 , multiple Ar 2 , multiple Ar 3 , multiple Ar 11 , multiple Ar 12 , multiple Ar 13 , multiple Ar 21 , multiple Ar 22, multiple Ar 23 , may be the same or different.

[0099] In addition, the above general formula (G L In the organic compound represented by 4), R 1 , R 2 , R 3 and R 4 each independently represents an alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted phenyl group; R 1 and R 2 or R 3 and R 4 may be bonded to each other to form a ring.

[0100] In addition, the above general formula (G L The organic compound represented by general formula (G 4) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms, preferably branched alkyl groups having 3 to 10 carbon atoms or cycloalkyl groups having 6 to 10 carbon atoms, and more preferably a tert-butyl group or a cyclohexyl group. Among these, a tert-butyl group is particularly preferred. L The number of alkyl groups in the organic compound represented by general formula (G 4) is preferably 1 to 30, since this allows for both a low refractive index and a stable film quality with high heat resistance. L Since the organic compound represented by general formula (G 4) has an amine structure and thus has hole transport properties, it can also be used in the hole transport layer of the organic EL layer. L The number of alkyl groups in the organic compound represented by 4) is preferably 1 or more and 30 or less, since this makes it easier to achieve both a low refractive index and carrier transportability.

[0101] In addition, the above general formula (G L All hydrogen atoms in the organic compound represented by 4) may be deuterium atoms independently of each other.

[0102] [ka]

[0103] However, the general formula (G L In the organic compound represented by 5), Ar 1 ~Ar 3 and Ar 11 ~Ar 13 are each independently one of a substituted or unsubstituted arylene group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroarylene group having 1 to 30 carbon atoms; Ar 4 ~Ar 6 and Ar 14 ~Ar 16 each independently represents one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0104] In addition, the above general formula (G L In the organic compound represented by formula 5), ​​n, m, l, p, q, and r each independently represent an integer of 0 to 3. When any one or more of n, m, l, p, q, and r is 2 or more, a plurality of Ar 1 , multiple Ar 2 , multiple Ar 3 , multiple Ar 11 , multiple Ar 12 , multiple Ar 13 may be the same or different.

[0105] In addition, the above general formula (G L 5), in the organic compound represented by R 1 and R 2 each independently represents an alkyl group having 1 to 10 carbon atoms or a substituted or unsubstituted phenyl group; R 1 and R 2 may be bonded to each other to form a ring.

[0106] In addition, the general formula (G LThe organic compound represented by general formula (G 5) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms, preferably branched alkyl groups having 3 to 10 carbon atoms or cycloalkyl groups having 6 to 10 carbon atoms, and more preferably a tert-butyl group or a cyclohexyl group. Among these, a tert-butyl group is particularly preferred. L The number of alkyl groups in the organic compound represented by general formula (G 5) is preferably 1 to 20, since this allows for both a low refractive index and a stable film quality with high heat resistance. L Since the organic compound represented by general formula (G 5) has an amine structure and thus has hole transport properties, it can also be used in the hole transport layer of the organic EL layer. L The number of alkyl groups in the organic compound represented by 5) is preferably 1 or more and 20 or less, since this makes it easier to achieve both a low refractive index and carrier transportability.

[0107] In addition, the general formula (G L All hydrogen atoms in the organic compound represented by 5) may be deuterium atoms independently of each other.

[0108] The above general formula (G L 1) to general formula (G L In 5), examples of the aryl group having 6 to 30 carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a mesityl group, a biphenyl-2-yl group (o-biphenyl group), a biphenyl-3-yl group (m-biphenyl group), a biphenyl-4-yl group (p-biphenyl group), a 1-naphthyl group, a 2-naphthyl group, a phenylnaphthyl group, a naphthylphenyl group, a terphenyl group, a fluorenyl group, a 9,9-dimethylfluorenyl group, a quaterphenyl group, a spirobifluorenyl group, a phenanthryl group, an anthryl group, a binaphthylphenyl group, a fluoranthenyl group, a triphenylenyl group, etc. When the aryl group having 6 to 30 carbon atoms has a substituent, the substituent can be an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aryl group having 6 to 13 carbon atoms.

[0109] In addition, the above general formula (G L 1) to general formula (G L In 5), specific examples of the heteroaryl group having 1 to 30 carbon atoms include a 1,3,5-triazin-2-yl group, a 1,2,4-triazin-3-yl group, a pyrimidin-4-yl group, a pyrazin-2-yl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, a dinaphthofuranyl group, a dinaphthothiophenyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, an indenocarbazolyl group, a dibenzocarbazolyl group, an indolyl group, a pyrrolyl group, a 1,2,3-triazolyl group, and a 1,2,4-triazolyl group. When the heteroaryl group having 1 to 30 carbon atoms has a substituent, examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aromatic hydrocarbon group having 6 to 13 carbon atoms.

[0110] The above general formula (G L 1) to general formula (G L In 5), examples of the arylene group having 6 to 30 carbon atoms include divalent groups obtained by removing one hydrogen atom from the groups exemplified above as the aryl group having 6 to 30 carbon atoms. When the arylene group having 6 to 30 carbon atoms has a substituent, examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 13 carbon atoms.

[0111] In addition, the above general formula (G L 1) to general formula (G LIn 5), examples of the heteroarylene group having 1 to 30 carbon atoms include divalent groups obtained by removing one hydrogen atom from the groups exemplified as the arylene group having 6 to 30 carbon atoms. When the arylene group having 6 to 30 carbon atoms has a substituent, examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 13 carbon atoms.

[0112] Examples of the linear or branched alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a heptyl group, an octyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, a 2,3-dimethylbutyl group, a 2-ethylhexyl group, a 1-ethylpropyl group, a nonyl group, a 3,7-dimethyl-1-octyl group, a 3,7-dimethyl-2-octyl group, and a decyl group.

[0113] Specific examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclononyl group, a cyclodecyl group, an adamantyl group, a bicyclo[2.2.1]heptyl group, a tricyclo[5.2.1.0(2,6)]decyl group, a noradamantyl group, a 1-methylcyclohexyl group, a bicyclo[2,2,2]octyl group, and a norbornyl group. When the cycloalkyl group having 3 to 10 carbon atoms has a substituent, examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, and an aryl group having 6 to 13 carbon atoms.

[0114] Specific examples of the monoamine compound containing an alkyl group having the above-described structure are preferably organic compounds represented by the following structural formulae (100) to (107), (200) to (224), (300) to (308), and (400) to (404).

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] [ka]

[0120] [ka]

[0121] As the monoamine compound containing an alkyl group, among the organic compounds represented by the structural formulae (100) to (107), (200) to (224), (300) to (308), and (400) to (404), the organic compounds represented by the structural formulae (200) to (224) and (400) to (404) have a relatively low refractive index, and in particular, the organic compounds represented by the structural formulae (400) to (404) are preferred because they have an even lower refractive index.

[0122] Since an organic compound containing a carbazole skeleton has a carbazole skeleton, it can be an organic compound having a high refractive index and low absorption in the visible light region compared to an organic compound not having such a skeleton. In addition, it can be an organic compound having a large refractive index anisotropy. Therefore, an organic compound containing a carbazole skeleton is preferably used as an organic compound having a high refractive index.

[0123] More specifically, the refractive index of ordinary light in a vapor-deposited film of an organic compound containing a carbazole skeleton at any wavelength from 380 nm to 500 nm is preferably 1.90 or more, and more preferably 2.00 or more, in order to improve light extraction efficiency.

[0124] Furthermore, the refractive index of ordinary light in a vapor-deposited film of an organic compound containing a carbazole skeleton at any wavelength from 500 nm to 600 nm is preferably 1.90 or more, and more preferably 1.93 or more, in order to improve light extraction efficiency.

[0125] Furthermore, the refractive index of ordinary light in a vapor-deposited film of an organic compound containing a carbazole skeleton at any wavelength from 600 nm to 760 nm is preferably 1.80 or more, and more preferably 1.85 or more, in order to improve light extraction efficiency.

[0126] It is preferable that the refractive index of the vapor-deposited film of the first substance at any wavelength between 380 nm and 760 nm is 1.40 or more, and it is more preferable that the refractive index of the vapor-deposited film of the second substance at any wavelength between 380 nm and 760 nm is 2.40 or less.

[0127] The organic compound containing a carbazole skeleton is represented by the following general formula (G H The organic compound represented by 1) is preferred.

[0128] [ka]

[0129] However, the general formula (G H In 1), R 11 ~R 18 each independently represents hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms; R 19 represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms. All hydrogen atoms may be replaced by deuterium, and the aromatic hydrocarbon group and heteroaromatic group may have a structure in which multiple rings are bonded to each other. When the group is composed of multiple rings, there may be multiple aromatic hydrocarbon groups, multiple heteroaromatic groups, or both an aromatic hydrocarbon group and a heteroaromatic group.

[0130] Furthermore, organic compounds containing a carbazole skeleton can further increase their refractive index by including a fused ring in the molecule. For example, to obtain an organic compound containing a carbazole skeleton that does not absorb visible light, it is preferable to include a phenanthrene ring or a naphthalene ring. These rings are preferably bonded to the carbazole ring as a substituent because they have a small molecular weight, can be sublimated at low temperatures, and provide high heat resistance and an improved refractive index. Furthermore, while the presence of just one phenanthrene ring or naphthalene ring in the molecule can provide a compound with a high refractive index, the presence of two or more phenanthrene rings can further improve the refractive index. For example, a binaphthalene structure in which two naphthalene rings are directly linked is preferable. Furthermore, when a binaphthalene structure is included as a substituent, the glass transition temperature (Tg) of the compound can be increased. Furthermore, the refractive index can be further improved by including a structure in which the 2-position of naphthalene is bonded to another group (i.e., a 2-naphthyl group). This is because the density of the organic compound in the formed film increases. In particular, if the partial structure contains a 2,2'-binaphthalene structure in which the 2-positions of naphthalene are bonded together, the refractive index can be further increased. Furthermore, if the partial structure contains a structure in which the 1-position of naphthalene is bonded to another group (i.e., a 1-naphthyl group), the Tg can be improved. By using an organic compound with such a molecular structure, it is possible to simultaneously achieve a high refractive index and the property of not absorbing visible light.

[0131] Furthermore, when the organic compound containing a carbazole skeleton has a biphenyl group as a substituent, it preferably has a p-biphenyl group.Compared to compounds having an m-biphenyl group or an o-biphenyl group, compounds having a p-biphenyl group have a higher molecular orientation when formed into a film, and can improve the ordinary refractive index.In addition, m-biphenyl group or o-biphenyl group can also be used, and in that case, the effect of reducing the sublimation temperature and suppressing the crystallization of the film can be expected.

[0132] The organic compound containing a carbazole skeleton is preferably an organic compound having a phenanthrene ring. Alternatively, the organic compound containing a carbazole skeleton is preferably an organic compound having a naphthalene ring. Note that, since an increase in the number of fused rings tends to increase the deposition temperature, and there is a concern that the compound may be decomposed by the heat during deposition, the number of naphthalene rings is preferably 4 or less, and more preferably 3 or less.

[0133] The organic compound containing a carbazole skeleton has one to three phenanthrene rings or two to four naphthalene rings as substituents on the carbazole ring, and thereby has a high refractive index, a low sublimation temperature (or vapor deposition temperature), is resistant to thermal decomposition during sublimation, and does not absorb visible light. From the viewpoint of the sublimation temperature, the number of naphthalene rings is more preferably two to three.

[0134] Furthermore, a low deposition temperature is beneficial for organic compounds used in light-emitting devices. In other words, because films can be formed at low temperatures, the organic compounds are less susceptible to heat during film formation, reducing thermal decomposition. The capping layer is formed after the organic compound layer and second electrode of the light-emitting device have been formed, and requires a certain thickness. Therefore, if a material with relatively low heat resistance is used for the organic compound layer of the light-emitting device, a high deposition temperature for the capping layer may cause the organic compound layer to deteriorate, resulting in reduced performance. However, by using an organic compound with a low deposition temperature as the capping layer, the thermal impact on the organic compound layer of the light-emitting device during deposition of the capping layer can be reduced, resulting in a light-emitting device with excellent performance.

[0135] Furthermore, particularly in mass production processes, the same material is heated continuously for a long period of time, and organic compounds that require high deposition temperatures are prone to decomposition. If the material decomposes, stable mass production becomes difficult. Therefore, organic compounds that can be formed into films at low temperatures can be formed into films without decomposition, making stable mass production possible.

[0136] The organic compound containing a carbazole skeleton may also have a heterocycle as a substituent. Examples of heteroatoms (also referred to as heteroatoms) contained in the heterocycle include nitrogen, oxygen, and sulfur. The presence of a heteroatom can increase the ordinary light refractive index. Alternatively, the glass transition temperature (Tg) may be increased. To improve the refractive index, the heterocycle preferably contains a five-membered heteroaromatic ring skeleton containing nitrogen, oxygen, or sulfur. For example, heterocycles containing a pyrrole skeleton, a furan skeleton, a thiophene skeleton, or an azole (e.g., imidazole, oxazole, thiazole, oxadiazole, or triazole) skeleton are preferred. In particular, compounds containing atoms with large atomic radii, such as sulfur, in their molecular structures are expected to have a high refractive index. Furthermore, a structure in which the fused ring contains a heteroatom is preferred because it simultaneously achieves the effect of improving Tg due to the fused ring and the effect of improving the refractive index due to the heteroatom. That is, fused heteroaromatic rings having five-membered rings containing nitrogen, oxygen, and sulfur are preferred, such as carbazole rings, dibenzofuran rings, benzonaphthofuran rings, dibenzothiophene rings, benzonaphthothiophene rings, benzoxazole rings, and benzothiazole rings. However, depending on the type of heterocycle (hereinafter including fused heterocycles), the presence of heteroatoms may reduce solubility in organic solvents, potentially leading to reduced reaction yields during synthesis and reduced purity during purification. Furthermore, the presence of heterocycles in the molecular structure may strengthen intermolecular interactions, leading to an increase in sublimation temperature. Therefore, the total number of heteroatoms contained in the compound other than the carbazole rings is preferably 3 or less, preferably 2 or less, and more preferably 1 or less. Alternatively, the total number of heterocycles contained in the compound other than the carbazole rings is preferably 3 or less, preferably 2 or less, and more preferably 1 or less.

[0137] The organic compound containing a carbazole skeleton is represented by the following general formula (G H 2), and the general formula (G H The organic compound represented by 3) is more preferred.

[0138] [ka]

[0139] However, the general formula (G H 2) In R 11 ~R 14 are each independently hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a group represented by the following general formula (G H 2-1), and R 15 ~R 18 are each independently hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a group represented by the following general formula (G H 2-2) represents any of the substituents represented by R 15 ~R 18 At least one of the following general formula (G H 2-2) is preferred. 31 represents a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 carbon atoms or a substituted or unsubstituted divalent aromatic heterocyclic group having 1 to 30 carbon atoms; Ar 32 represents a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted monovalent aromatic heterocyclic group having 1 to 30 carbon atoms. n11 represents an integer of 0 to 3, and n12 represents an integer of 1 to 3.

[0140] [ka]

[0141] However, the general formula (G H 2-1) and general formula (G H In 2-2), Ar 33 , Ar 35 , and Ar 36each independently represents a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 carbon atoms (also referred to as an arylene group) or a substituted or unsubstituted divalent aromatic heterocyclic group having 1 to 30 carbon atoms (also referred to as a heteroarylene group); Ar 34 and Ar 37 each independently represents a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms (also referred to as an aryl group) or a substituted or unsubstituted monovalent aromatic heterocyclic group having 1 to 30 carbon atoms (also referred to as a heteroaryl group); Ar 35 , Ar 36 and Ar 37 At least two of n13, n15, and n16 each independently represent an integer of 0 to 3, and n14 and n17 each independently represent an integer of 1 to 3. It is preferred that n13 is an integer of 0 to 3, and n14, n15, n16, and n17 each independently represent an integer of 1 to 3, with n15+n16+n17>n13+n14. It is preferred that n13 is an integer of 0 to 3, and n14, n15, n16, and n17 each independently represent an integer of 1 to 3, with n15+n16+n17>n13+n14. H 2-1) and general formula (G H 2-2) is the part marked with an asterisk and is represented by the general formula (G H 2).

[0142] In addition, when n11 is 2 or more, multiple Ar 11 may be the same or different substituents. 32 ~Ar 37 The same applies when there are multiple Ar 31 ~Ar 37 is preferably composed of carbon and hydrogen (including deuterium). 32 , Ar 34 , Ar 37 may be hydrogen (including deuterium).

[0143] Also, R 11 and R 12 , R 12 and R 13, R 13 and R 14 , R 14 and R 15 , R 15 and R 16 , R 16 and R 17 , and R 17 and R 18 For example, R 2 and R 3 When a benzene ring containing the benzocarbazole ring is formed, the benzene ring and the carbazole ring are condensed to form a structure containing a benzocarbazole ring. The presence of such a condensed structure can improve heat resistance and glass transition temperature (Tg). On the other hand, when such a condensed structure is not present, the molecular weight is reduced and the sublimation temperature can be improved.

[0144] Here, the general formula (G H 2) When a compound contains a naphthalene ring or a naphthalene skeleton, the ordinary light refractive index can be increased. In this specification, unless otherwise specified, a compound having a naphthalene ring refers to a compound having a naphthalene ring itself, and does not include a compound having a naphthalene ring as part of a condensed ring. Furthermore, a compound having a naphthalene skeleton includes a compound having naphthalene as part of the skeleton. Furthermore, this is not limited to naphthalene, and the same interpretation can be applied to other rings or skeletons.

[0145] Furthermore, by bonding the 2-positions of the naphthalene skeleton together, the ordinary light refractive index can be further increased. Alternatively, by not having a bond at the 1-position of the naphthalene skeleton, the refractive index can be increased. Furthermore, by using fused rings with three or fewer rings, the sublimation temperature can be lowered. Note that a fused ring with two rings refers to those with two rings, such as naphthalene, quinoxaline, or benzoxazole, and a fused ring with three rings refers to those with three rings, such as phenanthrene, anthracene, or carbazole. The same applies to those with four or more rings.

[0146] For example, Ar 35 , Ar 36 and Ar37 Preferably, at least two of Ar contain a substituted or unsubstituted naphthalene ring. 36 and Ar 37 Preferably, Ar contains a naphthalene ring. 36 and Ar 37 In the case of naphthalene, it is good for each naphthalene to be bonded at the 2-position to have a high refractive index. 36 and Ar 37 When the naphthalene is 2,2'-binaphthalene, the two naphthalenes bond at their 2-positions to form 2,2'-binaphthalene. This is a preferred molecular structure, as it contains 2,2'-binaphthalene as a partial structure of the organic compound.

[0147] In addition, naphthalene is preferably bonded to another group at the 2-position. 35 When the alkylene is naphthalene, the 2- and 6-positions are carbazolyl groups and Ar 36 It is good to bond with Ar. 36 In the case of naphthalene, Ar 37 and Ar 35 It is good to bond with Ar. 37 In the case of naphthalene, Ar is at the second position. 36 It is good to combine with

[0148] In particular, Ar 35 , and Ar 36 Ar is ranked 6th in the list. 35 , Ar 36 and Ar 37 When these two bond, a material with a high refractive index for ordinary light can be provided. By using this material in a device, a highly efficient device can be realized, and a device with low power consumption can be achieved. In addition, a material with high heat resistance can be provided. By using this material in a device, a highly efficient and highly heat-resistant device can be provided.

[0149] In addition, the above general formula (G HIn the organic compound represented by the general formula (G 2), it is preferable that n15+n16+n17>n13+n14. In this way, when the number of substituents bonded to one of the two benzene rings of the carbazole ring is greater than the number of substituents bonded to the other, the anisotropy of the refractive index tends to increase, which is preferable. H In the organic compound represented by formula (G 2), the number of arylene groups or heteroarylene groups connected to one of the two benzene rings of the carbazole ring is H 2) In the organic compound represented by Ar 35 ~Ar 37 is connected) is the number of arylene groups or heteroarylene groups that the substituents that are bonded to the other group are connected to (the number of arylene groups or heteroarylene groups that the substituents that are bonded to the other group are connected to (the number of arylene groups or heteroarylene groups that the substituents that are bonded to the other group are connected to) ... H 2) In the organic compound represented by Ar 33 ~Ar 34 When the number of bonds is larger than the number of bonds (G), the anisotropy of the refractive index tends to increase, which is preferable. In addition, it is considered that the intermolecular interaction is reduced, which makes it possible to reduce the sublimation temperature, which is preferable. H In the organic compound represented by 2), when n15+n16+n17>n11+n12, the anisotropy of the refractive index tends to be large, which is preferable. Also, by making such a relationship of n, it is possible to increase Tg.

[0150] [ka]

[0151] However, the general formula (G H 3) In R 11 ~R 14 are each independently hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a group represented by the following general formula (G H 3-1), and R 15 ~R 18are each independently hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a group represented by the following general formula (G H 3-2) represents any of the substituents represented by R 15 ~R 18 At least one of the following general formula (G H 3-2) is preferable. 31 represents a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 carbon atoms or a substituted or unsubstituted divalent aromatic heterocyclic group having 1 to 30 carbon atoms; Ar 32 represents a substituted or unsubstituted monovalent aromatic hydrocarbon group having 14 to 30 carbon atoms or a substituted or unsubstituted monovalent aromatic heterocyclic group having 1 to 30 carbon atoms. n11 represents an integer of 0 to 3, and n12 represents an integer of 1 to 3.

[0152] [ka]

[0153] However, the general formula (G H 3-1) and general formula (G H In 3-2), Ar 33 , and Ar 35 each independently represents a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 30 carbon atoms or a substituted or unsubstituted divalent aromatic heterocyclic group having 1 to 30 carbon atoms; Ar 34 , and Ar 37 each independently represents a substituted or unsubstituted monovalent aromatic hydrocarbon group having 6 to 30 carbon atoms or a substituted or unsubstituted monovalent aromatic heterocyclic group having 1 to 30 carbon atoms; Ar 35 , or Ar 37 At least one of the groups is phenanthrene, and Ar 37When n13 is a phenanthrene, it is bonded to another group at the 2nd or 3rd position of the phenanthrene. n13 and n15 represent an integer of 0 to 3, and n14 and n17 each independently represent an integer of 1 to 3. Note that n13 represents an integer of 0 to 3, and n14, n15, and n17 each independently represent an integer of 1 to 3. Note that, in the general formula (G H 3-1) and general formula (G H 3-2) is the part marked with an asterisk and is represented by the general formula (G H 3).

[0154] Also, Ar 35 and Ar 37 may each be two or more rings, preferably three or more rings.

[0155] Also, Ar 35 , and Ar 37 At least one of the rings has two or more rings, preferably at least one has three or more rings, and more preferably at least one has four or more fused rings. Examples of fused rings having four or more rings include a triphenylene ring, a benzoanthracene ring, a chrysene ring, and a benzophenanthrene ring. The use of a triphenylene ring is preferred because it increases the refractive index and Tg. When the sublimation temperature is to be lowered, the number of rings is preferably smaller.

[0156] In addition, the general formula (G H 3-1) and general formula (G H In 3-2), Ar 33 or Ar 34 At least one of the groups represents a fused ring, and Ar 35 or Ar 37 At least one of these represents a fused ring.

[0157] In addition, when n15 is 2 or more, multiple Ar 35 may be the same or different substituents. 37 The same applies when there are multiple Ar 35 and Ar 37is preferably composed of carbon and hydrogen (including deuterium). 32 , Ar 34 , Ar 37 may be hydrogen (including deuterium).

[0158] Here, the general formula (G H In 3-2), Ar 35 or Ar 37 When Ar is phenanthrene, the phenanthrene can be bonded to another group at the 2- or 3-position to increase the ordinary refractive index. 37 When is phenanthrene, it is preferable that the phenanthrene is bonded to another group at the 2- or 3-position, since this increases the effect of increasing the ordinary light refractive index.

[0159] In addition, the above general formula (G H In the organic compound represented by the general formula (G 3), it is preferable that n15+n17>n13+n14. In this way, when the number of substituents bonded to one of the two benzene rings of the carbazole ring is greater than the number of substituents bonded to the other, the anisotropy of the refractive index tends to increase, which is preferable. H In the organic compound represented by formula (G 3), the number of divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups connected to one of the two benzene rings of the carbazole ring is determined by the number of divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups connected to the substituent (the number of divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups connected to the substituent) of the organic compound represented by formula (G 3). H 3) In the organic compound represented by Ar 35 and Ar 37 is connected) is the number of divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups that the substituents that are bonded to the other group have connected to (the ...) (the number of divalent aromatic hydrocarbon groups or divalent aromatic heterocyclic groups that the substituents that are bonded to the other group have connected H 3) In the organic compound represented by Ar 33 and Ar 34 When the number of bonds is larger than the number of bonds (G), the anisotropy of the refractive index tends to increase, which is preferable. In addition, it is considered that the intermolecular interaction is reduced, which makes it possible to reduce the sublimation temperature, which is preferable. HIn the organic compound represented by 3), when n15+n17>n11+n12, the anisotropy of the refractive index tends to be large, which is preferable. Also, by making such a relationship of n, it is possible to increase Tg.

[0160] In addition, the general formula (G H 1) to general formula (G H 3) In R 11 ~R 18 When the alkyl group having 1 to 6 carbon atoms is an alkyl group having 1 to 6 carbon atoms, for example, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, a 2,3-dimethylbutyl group, etc. When the alkyl group having 1 to 6 carbon atoms has a substituent, the substituent can be a cycloalkyl group having 1 to 5 carbon atoms or an aromatic hydrocarbon group having 6 to 13 carbon atoms.

[0161] General formula (G H 1) to general formula (G H 3) In R 11 ~R 18 In the case of a cycloalkyl group having 3 to 6 carbon atoms, for example, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a 1-methylcyclohexyl group, a cycloheptyl group, an adamantyl group, a bicyclo[2,2,2]octyl group, a norbornyl group, etc. In the case where the alkyl group having 1 to 6 carbon atoms has a substituent, examples of the substituent include a cycloalkyl group having 1 to 4 carbon atoms and an aromatic hydrocarbon group having 6 to 13 carbon atoms.

[0162] In addition, the general formula (G H 1) to general formula (G HIn 3), examples of the aromatic hydrocarbon group having 6 to 30 carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a mesityl group, a biphenyl-2-yl group (o-biphenyl group), a biphenyl-3-yl group (m-biphenyl group), a biphenyl-4-yl group (p-biphenyl group), a 1-naphthyl group, a 2-naphthyl group, a phenylnaphthyl group, a naphthylphenyl group, a terphenyl group, a fluorenyl group, a 9,9-dimethylfluorenyl group, a quaterphenyl group, a spirobifluorenyl group, a phenanthryl group, an anthryl group, a binaphthylphenyl group, a fluoranthenyl group, a triphenylenyl group, etc. When the aromatic hydrocarbon group having 6 to 30 carbon atoms has a substituent, the substituent can be an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aromatic hydrocarbon group having 6 to 13 carbon atoms.

[0163] In addition, the general formula (G H 1) to general formula (G H In 3), specific examples of the aromatic heterocyclic group having 1 to 30 carbon atoms include a 1,3,5-triazin-2-yl group, a 1,2,4-triazin-3-yl group, a pyrimidin-4-yl group, a pyrazin-2-yl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, an indenocarbazolyl group, a dibenzocarbazolyl group, etc. When the aromatic heterocyclic group having 1 to 30 carbon atoms has a substituent, the substituent can be an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, or an aromatic hydrocarbon group having 6 to 13 carbon atoms.

[0164] General formula (G H 2), general formula (G H 3), general formula (G H 2-1), general formula (G H 2-2), general formula (G H 3-1) and general formula (G H 3-2) R 11~R 18 , Ar 31 ~Ar 37 is an aromatic hydrocarbon group having 6 to 30 carbon atoms or an aromatic heterocyclic group having 3 to 30 carbon atoms, it can be represented by a group having a structure in which hydrogen atoms, the number of which corresponds to the number of substitution positions, have been removed from one ring of the aromatic hydrocarbon or aromatic heterocyclic ring represented by any of the following structural formulas (Ar-1) to (Ar-33):

[0165] For example, a naphthyl group refers to a monovalent substituent obtained by removing one hydrogen atom from a naphthalene ring (shown in the following structural formula (Ar-17)). Also, a naphthalene-diyl group refers to a divalent substituent obtained by removing two hydrogen atoms from a naphthalene ring. The same applies to other structural formulas (Ar-1) to (Ar-33). Therefore, for example, the above general formula (G H In 2-2), Ar 35 is a pyridine ring (represented by the following structural formula (Ar-5)), Ar 36 and Ar 37 is a naphthalene ring, strictly speaking, 35 is a pyridine-diyl group, Ar 36 is a naphthalene-diyl group, Ar 37 is a naphthyl group, but for simplicity it is expressed as "Ar 35 is a pyridine ring, and Ar 36 and Ar 37 This can also be expressed as "the ring is a naphthalene ring."

[0166] [ka]

[0167] Furthermore, when the aromatic hydrocarbon group or aromatic heterocyclic group has a substituent, the substituent can be a cyano group, a halogen group, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an aromatic hydrocarbon group having 6 to 13 carbon atoms, or an aromatic heterocyclic group having 3 to 10 carbon atoms. The presence of a cyano group or a halogen group is expected to have the effect of reducing the driving voltage of the device. Furthermore, the presence of an alkyl group or a cycloalkyl group is expected to have the effect of reducing the sublimation temperature, so that the compound can be applied to each layer, including the cap layer. Furthermore, when the compound has an alkyl group or a cycloalkyl group, the ordinary refractive index may become small, so the compound is particularly suitable for use in layers that require a small ordinary refractive index, such as a transport layer (hole transport layer or electron transport layer). Note that R 11 ~R 18 The same effect can be expected when a cyano group, a halogen group, an alkyl group, or a cycloalkyl group is used as the alkyl group.

[0168] As described above, organic compounds containing a carbazole skeleton contain a fused ring in the molecule, do not absorb visible light, can be sublimated at low temperatures, and have a molecular structure that provides high heat resistance and an improved refractive index. On the other hand, monoamine compounds containing the alkyl group can be easily deposited at a relatively low deposition temperature, provide good and stable film quality, and can be made into a molecular structure with a short effective conjugation length, so they do not absorb visible light and have a molecular structure with a low refractive index.

[0169] Comparing organic compounds containing a carbazole skeleton with monoamine compounds containing an alkyl group, the monoamine compounds containing an alkyl group have a lower sublimation temperature due to the alkyl group, and their molecular structure makes them less susceptible to changes in film quality such as crystallization, making it possible to form very stable films by low-temperature deposition.

[0170] On the other hand, organic compounds containing a carbazole skeleton are characterized by a high refractive index, and it is preferable that they do not contain alkyl groups. Therefore, organic compounds containing a carbazole skeleton have a high refractive index and a high glass transition temperature (Tg), but when stored in a high-temperature environment in the form of a thin film, changes in film quality such as crystallization may occur.

[0171] However, by including a capping layer containing a film of an organic compound having a carbazole skeleton and a film of a monoamine compound having an alkyl group, preferably by laminating the film of the organic compound having a carbazole skeleton and the film of the monoamine compound having an alkyl group in contact with each other, a very stable film or capping layer can be provided, which is an effect obtained by combining the film of the organic compound having a carbazole skeleton and the film of the monoamine compound having an alkyl group.

[0172] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0173] Information such as the layer structure of the cap layer 155, the molecular weight of the contained substances, and the number of contained substances can be obtained by using time-of-flight secondary ion mass spectrometry (ToF-SIMS). In this case, depending on the film thickness of the cap layer or the measurement conditions, even if the cap layer has a layer structure of a layer containing a first substance and a layer containing a second substance, it may be detected as a mixed layer.

[0174] This embodiment mode can be used in any combination with other embodiments.

[0175] (Embodiment 2) In this embodiment, a light-emitting device 600 according to one embodiment of the present invention will be described in detail. The light-emitting device 600 illustrated in FIGS. 1A to 1C includes an organic compound layer 103 between a first electrode 101 provided over an insulating layer 1000 and a second electrode 102 facing the first electrode 101. A capping layer 155 is provided over the second electrode 102. The organic compound layer 103 has a stacked structure including functional layers such as 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. The organic compound layer 103 preferably has a stacked structure including functional layers each containing an organic compound, each of which is functionally separated and has properties corresponding to its role, as illustrated in FIGS. 1A to 1C.

[0176] These functional layers are required to have a variety of functions, and typical functional layers include, for example, a carrier injection layer, a carrier transport layer, a light-emitting layer, a photoelectric conversion layer, a charge generation layer, a carrier blocking layer, and an exciton blocking layer. Each functional layer may also have other functions. Each functional layer may have a laminated structure.

[0177] When the hole transport layer 112 has a laminated structure, the layer in contact with the light-emitting layer 113 may be particularly referred to as the electron blocking layer, and when the electron transport layer 114 has a laminated structure, the layer in contact with the light-emitting layer may be particularly referred to as the hole blocking layer.

[0178] In this embodiment, the first electrode 101 functions as an anode and the second electrode 102 functions as a cathode, but the reverse is also possible. However, the second electrode 102 is an electrode that transmits visible light, and the light-emitting device of one embodiment of the present invention is a so-called top-emission light-emitting device.

[0179] The configuration of the cap layer 155 has been described in detail in the first embodiment, so a repetitive description will be omitted. Please refer to the first embodiment.

[0180] The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a large work function (specifically, 4.0 eV or higher). Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide (ITSO), indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are usually formed by sputtering, but they may also be prepared by applying a sol-gel method. For example, indium oxide-zinc oxide can be formed by sputtering using a target in which 1 to 20 wt % of zinc oxide is added to indium oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials that can be used for the anode include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), and nitrides of metal materials (e.g., titanium nitride). A layer formed by stacking these materials can also be used as the anode. For example, a film formed by stacking Al, Ti, and ITSO on Ti in this order is preferred because of its high reflectivity, high efficiency, and the ability to achieve high resolution of several thousand ppi. Graphene can also be used as the anode material. In addition, by using a composite material capable of forming the hole injection layer 111 described later as a layer in contact with the anode (typically the hole injection layer), it becomes possible to select an electrode material regardless of the work function.

[0181] The hole injection layer 111 is provided in contact with the anode and has the function of facilitating the injection of holes into the organic compound layer 103. The hole injection layer 111 can be formed of a phthalocyanine-based compound or complex compound such as phthalocyanine (abbreviation: HPc) or copper phthalocyanine (abbreviation: CuPc), an aromatic amine compound such as 4,4′-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) or 4,4′-bis(N-{4-[N′-(3-methylphenyl)-N′-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / polystyrenesulfonic acid (abbreviation: PEDOT / PSS), or the like.

[0182] Alternatively, the hole injection layer 111 may be formed of a substance having electron acceptor properties. Examples of the substance having acceptor properties include organic compounds having an electron-withdrawing group (such as a halogen group or a cyano group), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a fused aromatic ring having multiple heteroatoms, such as HAT-CN, are preferred because of their thermal stability. Radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups, cyano groups, etc.) are also preferred because of their extremely high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenetris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds described above, the acceptor material can also be a transition metal oxide such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. The acceptor material can extract electrons from the adjacent hole transport layer (or hole transport material) by applying an electric field.

[0183] The hole-injecting layer 111 is preferably formed using a composite material containing the above-mentioned material having an acceptor property and a substance having a hole-transport property.

[0184] As a substance having hole transport properties used in a composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as a substance having hole transport properties used in a composite material, a 1×10 -6 cm 2 Preferably, the compound has a hole mobility of 1 / Vs or more. The hole-transporting substance used in the composite material is preferably a compound having a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the fused aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, or the like is preferred. As the π-electron-rich heteroaromatic ring, a fused aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton is preferred. Specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further fused to the above ring is preferred.

[0185] Such a substance having hole-transporting properties preferably has at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the substance may be an aromatic amine having a substituent containing 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. It is preferable that the substance having hole-transporting properties has an N,N-bis(4-biphenyl)amino group, since this allows the fabrication of a light-emitting device with a long lifetime.

[0186] Specific examples of the substance having the hole transporting property as described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-yl, [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: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβN B-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviated as BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviated as BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviated as BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviated as BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl] 4'-[4'-(3-phenyl-9H-carbazol-9-yl)biphenyl-4-yl]-4''-phenyltriphenylamine (abbreviated as TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviated as αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviated as YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N- Bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4' -[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'- Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis( Examples of such amines include N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine.

[0187] In addition, other aromatic amine compounds such as N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) can also be used as the substance having hole-transporting properties.

[0188] By forming the hole injection layer 111, the hole injection property becomes good, and a light emitting device with a low driving voltage can be obtained.

[0189] Among substances having acceptor properties, organic compounds having acceptor properties are easy to use because they can be easily vapor-deposited and formed into a film.

[0190] The hole-transport layer 112 is formed by containing a substance having a hole-transport property. -6 cm 2 It is preferable that the hole mobility is / Vs or more.

[0191] Examples of the hole-transporting substance include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3-methylphenyl-4,4'-diaminobiphenyl (abbreviation: 4,4'-bis(9H-fluoren-2-yl)triphenylamine) ... '-(9-Phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl) Compounds with an aromatic amine skeleton, such as 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di( N-carbazolyl)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-3,3'-Bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terf phenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3 '-9H,9'H-Bicarbazole, 9-(2-naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylen-2-yl)-9'-[1,1':3',1"-taphe compounds having a carbazole skeleton such as [4-yl-3,3'-9H,9'H-bicarbazole]; compounds having a thiophene skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV);Examples of the compounds include compounds having a furan skeleton, such as 4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the compounds mentioned above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. In addition, the organic compounds listed as substances having hole transport properties used in the composite material of the hole injection layer 111 can also be suitably used as materials for the hole transport layer 112.

[0192] The luminescent center substance contained in the light-emitting layer 113 may be a fluorescent luminescent substance, a phosphorescent luminescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or any other luminescent substance.

[0193] Examples of materials that can be used as the fluorescent substance in the light-emitting layer 113 include the following: Other fluorescent substances can also be used.

[0194] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviated as DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA) , 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyra N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhTD), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-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]fluoranthene-3,10-diamine (abbreviation: p-mPhTD), Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB),6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyren-diyl)bis[(6-phenylbenzo[b]naphtho]] Examples include N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviated as 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred due to their high hole-trapping properties and excellent luminous efficiency and reliability.

[0195] In addition, 5,9-diphenyl-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: DABNA3), Amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborin (abbreviation: Me-tBu4DABNA), N 7 ,N 7 ,N 13 ,N 13 Fused heteroaromatic compounds containing nitrogen and boron, such as 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazaborine-7,13-diamine (abbreviation: ν-DABNA) and 2-(4-tert-butylphenyl)benz[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc), are particularly suitable for use as compounds having a diazaboranaphthoanthracene skeleton, since they have a narrow emission spectrum and can emit blue light with good color purity.

[0196] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-Y) and the like can be preferably used.

[0197] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, the phosphorescent material is preferably a metal complex, particularly an iridium complex or a platinum complex, and examples thereof include the following.

[0198] Organometallic iridium complexes with a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]). , organometallic iridium complexes with a 1H-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]), fac-tris[1-(2,6-di [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN3}-4-cyano organometallic iridium complexes with an imidazole skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: CNImIr), organometallic complexes with a benzimidazolidene skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), and organometallic complexes with a benzimidazolidene skeleton, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ Examples include organometallic iridium complexes with phenylpyridine derivatives containing electron-withdrawing groups, such as ]iridium(III) acetylacetonate (abbreviated as FIracac), and platinum complexes such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC1)platinum(II) (abbreviated as PtON-TBBI). These compounds exhibit blue phosphorescence, with peak emission wavelengths in the 450-520 nm range. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium can also be used.

[0199] 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- Organometallic iridium complexes with a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]) and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’) iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), {2- (Methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro[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-d3-methyl Ir(ppy)2(mbfpypy-d3) and Ir(ppy)2(mbfpypy-d3) are bis[2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) compounds. ) (abbreviation: Ir(ppy)2(mdppy)), [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-(2-pyridinyl-κN)benzofuro[2,In addition to organometallic iridium complexes with a pyridine skeleton, such as [2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium (abbreviated as [Ir(ppy)2(mdppy)]), and tris{2-[5-(methyl-d3)-4-phenyl-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviated as Ir(5m4dppy-d3)3), we have also developed organometallic iridium complexes with a pyridine skeleton, such as [2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridinyl-κN] )phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenolato-κO)platinum(II) (abbreviation: Pt(tBudppymmtBubiz-tBubp)), [2-(4-(3,5-di-tert-butylphenyl)-6-{3-[4-(5'-tert-butyl[1,1':3',1''-terphenyl]-2'-yl)-2-pyridinyl-κN]phenyl-κC2}-2-pyridinyl-κN)phenolato-κO]platinum(II) (abbreviation: Pt(4tButpppypyp-mmtBup)), and rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). These compounds exhibit phosphorescence with a predominantly green hue, with emission peaks in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred because they are remarkably reliable and offer excellent luminous efficiency. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0200] and organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]). Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’) iridium(III) acetylacetonate (abbreviated as [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), and (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). In addition to iridium complexes, platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP) and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]) are examples of iridium complexes. These compounds exhibit red phosphorescence with peak emission in the wavelength range from 600 nm to 700 nm. Organometallic iridium complexes with a pyrazine skeleton also exhibit excellent red chromaticity. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0201] In one embodiment of the present invention, the use of a deuterated compound as the luminescent center substance improves luminous efficiency, and therefore the luminescent center substance is preferably a deuterated material.

[0202] In addition to the phosphorescent compounds described above, known phosphorescent compounds may be selected and used.

[0203] TADF materials include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also available are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP), all of which are shown in the following structural formulas.

[0204] [ka]

[0205] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, such as 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron-deficient heteroaromatic ring, pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptor properties and good reliability. Furthermore, among the skeletons having a π-electron-rich heteroaromatic ring, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable.The furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. The pyrrole skeleton is particularly preferably an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because the electron-donating ability of the π-electron-rich heteroaromatic ring and the electron-accepting ability of the π-electron-deficient heteroaromatic ring are both enhanced, thereby reducing the energy difference between the S1 level and the T1 level, thereby enabling efficient thermally activated delayed fluorescence. Instead of the π-electron-deficient heteroaromatic ring, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used. The π-electron-rich skeleton may be, for example, an aromatic amine skeleton or a phenazine skeleton. Examples of usable π-electron-deficient skeletons include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0206] [ka]

[0207] In addition, TADF materials that are in thermal equilibrium between the singlet excited state and the triplet excited state may also be used. Such TADF materials have a shorter emission lifetime (excitation lifetime), which can suppress efficiency decline in the high brightness range of light-emitting devices. Specific examples include materials with the molecular structure shown below.

[0208] [ka]

[0209] TADF materials are materials with a small difference between the S1 and T1 levels, and have the ability to convert triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy (reverse intersystem crossing) using a small amount of thermal energy, allowing for efficient generation of a singlet excited state. Triplet excitation energy can also be converted into light emission.

[0210] Furthermore, exciplexes (also known as exciplexes), which form an excited state with two types of substances, have an extremely small difference between the S1 and T1 levels and function as TADF materials that can convert triplet excitation energy into singlet excitation energy.

[0211] Note that the T1 level can be measured using a phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K). For a TADF material, when a tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side and the energy of the wavelength of the extrapolated line is taken as the S1 level, and a tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side and the energy of the wavelength of the extrapolated line is taken as the T1 level, the difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0212] When a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0213] As a host material for the light-emitting layer 113, various carrier transporting materials such as a substance having an electron transporting property and / or a substance having a hole transporting property, or the above-mentioned TADF material can be used.

[0214] Preferred examples of substances having hole-transporting properties that can be used as a host material for the light-emitting layer 113 include organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton. The π-electron-rich heteroaromatic ring is preferably a fused aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further fused to one of these rings.

[0215] The hole-transporting substance preferably has at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the hole-transporting substance may be an aromatic amine having a substituent containing 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. It is preferable that the hole-transporting substance is an organic compound having an N,N-bis(4-biphenyl)amino group, since this allows the fabrication of a light-emitting device with a long lifetime.

[0216] As such an organic compound, for example, the following organic compounds are preferable: 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3 ... mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBANB), )triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), compounds with an aromatic amine skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl ( abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 3,9-bis(9-phenyl-9H-carbazole-3-yl)-9H-carbazole (abbreviation: PCCzPC), 9-(biphenyl-4-yl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzBP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-Bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3, 3'-Bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H ,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-Bis(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylen-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,Compounds with a carbazole skeleton, such as 9'-bi-9H-carbazole (abbreviation: PSiCzCz) and 9'-[3-(triphenylsilyl)phenyl]-9'H-9,3':6',9''-tercarbazole (abbreviation: PSiCzGI), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), and 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-I) Examples of suitable compounds include compounds having a thiophene skeleton, such as 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. The organic compounds listed as examples of materials having hole transport properties for the hole transport layer can also be used.

[0217] The electron transporting substance that can be used as the host material of the light-emitting layer 113 is a substance having an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600 or more. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can also be used as long as they have a higher electron transporting property than holes.

[0218] Preferred examples of the substance having electron transport properties include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring having an azole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0219] Among these, organic compounds containing a heteroaromatic ring having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred because of their high reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reduced driving voltage. In addition, benzofuropyrimidine skeletons, benzothienopyrimidine skeletons, benzofuropyrazine skeletons, and benzothienopyrazine skeletons are preferred because of their high acceptor properties and high reliability.

[0220] As the organic compound having a π-electron-deficient heteroaromatic ring skeleton, for example, the following organic compounds are preferable: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-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-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and other organic compounds with an azole skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10-phenane Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9 H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3 '-(Dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis (Biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2, 6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviated as 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as 2,4NP-6PyPPm), 4-[3, 5-Bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), etc. The organic compounds having the diazine skeleton are 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), and 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl Indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTzn) ), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTp BPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-Triazine (abbreviation: βNP-SFx(4)Tzn), 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)Tzn), 3-{3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl ]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBfTzn), 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazine-4,3''-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTzn), and 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothienyl]-2-phenyl-9H-carbazole (abbreviation: PCzDBtTzn) are examples of organic compounds containing a heteroaromatic ring with a triazine skeleton. In addition, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred because of their high reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing driving voltage.

[0221] The TADF materials that can be used as host materials are the same as those listed above. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy through reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby improving the luminous 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.

[0222] This is effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0223] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material, as this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient light emission.

[0224] Furthermore, to efficiently generate singlet excitation energy from triplet excitation energy through reverse intersystem crossing, carrier recombination is preferred in the TADF material. Furthermore, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to triplet excitation energy in the fluorescent material. To achieve this, the fluorescent material preferably has a protecting group around the luminophore (the skeleton responsible for light emission) of the fluorescent material. The protecting group is preferably a substituent without a π bond, and is preferably a saturated hydrocarbon. Specific examples include alkyl groups with 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups with 3 to 10 carbon atoms, and trialkylsilyl groups with 3 to 10 carbon atoms. Multiple protecting groups are even more preferred. Substituents without a π bond have poor carrier transport properties, allowing for increased distance between the TADF material and the luminophore of the fluorescent material without significantly affecting carrier transport or carrier recombination. Here, the term "luminophore" refers to the atomic group (skeleton) responsible for light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring. Examples of such luminophores include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton. In particular, fluorescent materials having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because of their high fluorescence quantum yield.

[0225] When a fluorescent substance is used as the light-emitting substance in the light-emitting layer 113, a material having an acene skeleton, particularly an anthracene skeleton, is suitable as the host material. Using a substance having an anthracene skeleton as a host material for a fluorescent substance makes it possible to realize an light-emitting layer with both excellent luminous efficiency and durability. Substances having an anthracene skeleton, particularly substances having a diphenylanthracene skeleton, are preferred as host materials because they are chemically stable. Furthermore, host materials having a carbazole skeleton are preferred because they enhance hole injection and transport properties. However, host materials containing a benzocarbazole skeleton, in which a benzene ring is further condensed to carbazole, are more preferred because their HOMO level is about 0.1 eV higher than that of a host material containing a carbazole skeleton, making it easier for holes to enter. In particular, host materials containing a dibenzocarbazole skeleton are preferred because their HOMO level is about 0.1 eV higher than that of a host material containing a carbazole skeleton, making it easier for holes to enter, as well as providing excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). From the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Furthermore, a dibenzofuran skeleton is preferable because it can ensure reliability without lowering the T1 level.

[0226] Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4' -yl]anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthryl)benzo Examples include zo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices because they exhibit very good properties.

[0227] The host material may be a mixture of multiple substances, and when a mixture of host materials is used, it is preferable to mix a substance having electron-transporting properties with a substance having hole-transporting properties. By mixing a substance having electron-transporting properties with a substance having hole-transporting properties, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can also be easily controlled. The weight ratio of the contents of the substance having hole-transporting properties to the substance having electron-transporting properties is preferably 1:19 to 19:1 (substance having hole-transporting properties:substance having electron-transporting properties).

[0228] A phosphorescent material can be used as part of the mixed host material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as an emitting material.

[0229] These mixed materials may also form an exciplex. The exciplex is preferably formed by selecting a combination that forms an exciplex that emits light that overlaps with the lowest-energy absorption band of the light-emitting material, because this allows for smooth energy transfer and efficient light emission. Furthermore, this configuration is also preferable because it reduces the driving voltage.

[0230] At least one of the materials forming the exciplex may be a phosphorescent material, which allows triplet excitation energy to be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0231] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the hole-transporting substance is higher than or equal to the HOMO level of the electron-transporting substance. It is also preferable that the LUMO level of the hole-transporting substance is higher than or equal to the LUMO level of the electron-transporting substance. The LUMO level and HOMO level of a material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0232] The formation of exciplexes can be confirmed by, for example, comparing the emission spectra of a hole-transporting substance, an electron-transporting substance, and a mixed film of these materials and observing the phenomenon that the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak at longer wavelengths). Alternatively, the formation of exciplexes can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting substance, the transient PL of an electron-transporting substance, and a mixed film of these materials and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lived component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL can also be interpreted as transient electroluminescence (EL). The formation of exciplexes can also be confirmed by comparing the transient EL of a hole-transporting substance, the transient EL of an electron-transporting substance, and a mixed film of these materials and observing differences in transient response.

[0233] The electron-transporting layer 114 is a layer containing a substance having an electron-transporting property. The substance having an electron-transporting property is a material having an electron mobility of 1×10 or more at a square root of an electric field strength [V / cm] of 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can be used as long as they have a higher electron transporting property than holes. Note that the organic compound is preferably an organic compound having a π-electron-deficient heteroaromatic ring. The organic compound having a π-electron-deficient heteroaromatic ring is preferably one or more of, for example, an organic compound having a heteroaromatic ring with an azole skeleton, an organic compound having a heteroaromatic ring with a pyridine skeleton, an organic compound having a heteroaromatic ring with a diazine skeleton, and an organic compound having a heteroaromatic ring with a triazine skeleton.

[0234] The electron-transporting material for the electron-transporting layer 114 can be the same as the organic compounds that can be used as the electron-transporting material for the light-emitting layer 113. Among these, organic compounds containing a heteroaromatic ring with a diazine skeleton, an organic compound containing a heteroaromatic ring with a pyridine skeleton, and an organic compound containing a heteroaromatic ring with a triazine skeleton are preferred because of their excellent reliability. In particular, organic compounds containing a heteroaromatic ring with a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring with a triazine skeleton have high electron-transporting properties and contribute to reduced driving voltage. Organic compounds containing a phenanthroline skeleton, such as mTpPPhen, PnNPhen, and mPPhen2P, are particularly preferred, and organic compounds containing a phenanthroline dimer structure, such as mPPhen2P, are more preferred because of their excellent stability.

[0235] The electron transport layer 114 may have a laminated structure. A layer in the electron transport layer 114 having a laminated structure that is in contact with the light-emitting layer 113 may function as a hole-blocking layer. When the electron transport layer in contact with the light-emitting layer is made to function as a hole-blocking layer, it is preferable to use a material whose HOMO level is lower than the HOMO level of the material contained in the light-emitting layer 113 by 0.5 eV or more.

[0236] The electron-injection layer 115 may be a layer containing a compound or complex of an alkali metal or alkaline earth metal such as 8-hydroxyquinolinato-lithium (abbreviation: Liq), or 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: hpp2Py). The electron-injection layer 115 may be a layer made of a substance having electron-transporting properties containing an alkali metal, an alkaline earth metal, or a compound thereof.

[0237] Alternatively, a charge generation layer 116 may be provided instead of the electron injection layer 115 (FIG. 1(C)). The charge generation layer 116 is a layer that can inject holes into a layer in contact with the cathode side of the charge generation layer 116 and electrons into a layer in contact with the anode side of the charge generation layer 116 by applying a potential thereto. The charge generation layer 116 includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material listed above as a material that can be used to form the hole injection layer 111. The P-type layer 117 may also be formed by laminating a film containing an acceptor material and a film containing a hole transport material, both of which are materials that can be used to form the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the cathode, thereby operating the light-emitting device.

[0238] It is preferable that the charge generating layer 116 be provided with either or both of an electron relay layer 118 and an electron injection buffer layer 119 in addition to the P-type layer 117 .

[0239] The electron relay layer 118 contains at least a substance having electron transport properties and functions to prevent interaction between the electron injection buffer layer 119 and the P-type layer 117, thereby smoothly transferring electrons. The LUMO level of the substance having electron transport properties contained in the electron relay layer 118 is preferably located between the LUMO level of the acceptor substance in the P-type layer 117 and the LUMO level of the substance contained in the layer of the electron transport layer 114 that is in contact with the charge generation layer 116. The specific energy level of the LUMO level of the substance having electron transport properties used in the electron relay layer 118 is preferably −5.0 eV or higher, preferably −5.0 eV or higher to −3.0 eV or lower, more preferably −4.30 eV or higher to −3.00 eV or lower, and even more preferably −4.30 eV or higher to −3.30 eV or lower, in order to suppress an increase in driving voltage. Note that the substance having electron transport properties used in the electron relay layer 118 is preferably a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0240] Specific examples of the substance having electron transport properties that can be used in the electron relay layer 118 include diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), perylene tetracarboxylic acid derivatives such as 3,4,9,10-perylene tetracarboxylic diimide (abbreviation: PTCDI) and 3,4,9,10-perylene tetracarboxylic-bis-benzimidazole (abbreviation: PTCBI), (C60-Ih)[5,6]fullerene (abbreviation: C60), and (C70-D5h)[5,6]fullerene (abbreviation: C70). Compounds having a heterophane skeleton, which is a cyclophane skeleton containing a heterocycle, can also be used, including phthalocyanine compounds such as phthalocyanine (abbreviated as HPc). Metal phthalocyanines containing copper, zinc, cobalt, iron, chromium, nickel, etc., such as copper phthalocyanine (abbreviated as CuPc), zinc phthalocyanine (abbreviated as ZnPc), cobalt phthalocyanine (abbreviated as CoPc), iron phthalocyanine (abbreviated as FePc), tin phthalocyanine (abbreviated as SnPc), tin oxide phthalocyanine (abbreviated as SnOPc), titanium oxide phthalocyanine (abbreviated as TiOPc), and vanadium oxide phthalocyanine (abbreviated as VOPc), as well as derivatives thereof, can also be used. Also preferred are metal complexes of the phthalocyanine series, such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine.

[0241] For the electron injection buffer layer 119, it is preferable to use a material with high electron injection properties, such as a metal or a metal compound, particularly an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)).

[0242] When the electron-injection buffer layer 119 is formed to contain a substance having electron-transporting properties and a donor substance, the donor substance can be a metal or a metal compound, in particular, an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)), or organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, or decamethylnickelocene. Note that the substance having electron-transporting properties can be formed using the same material as the material constituting the electron-transporting layer 114 described above.

[0243] The second electrode 102 is an electrode including a cathode. The second electrode 102 may have a laminated structure, in which case the layer in contact with the organic compound layer 103 functions as the cathode. Materials that form the cathode include metals, alloys, electrically conductive compounds, and mixtures thereof, each having a low work function (specifically, 3.8 eV or less). Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), alloys (MgAg, AlLi), and compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), etc.) containing these elements, rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these elements. However, by providing the electron injection layer 115 or a thin film of the above-mentioned material with a small work function between the second electrode 102 and the electron transport layer, various conductive materials, such as Al, Ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide, can be used as the cathode regardless of the magnitude of the work function.

[0244] Note that the light-emitting device of one embodiment of the present invention can be a light-emitting device that emits light from the second electrode 102 side by forming the second electrode 102 using a material that transmits visible light.

[0245] These conductive materials can be formed into films by dry methods such as vacuum deposition or sputtering, inkjet methods, spin coating, etc. Alternatively, they may be formed by wet methods using a sol-gel method, or by wet methods using a paste of a metal material.

[0246] In addition, various methods, whether dry or wet, can be used to form the organic compound layer 103. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, spin coating, or the like may be used.

[0247] Furthermore, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0248] Next, an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are stacked (also referred to as a stacked element or a tandem element) will be described with reference to FIG. 2. This light-emitting device has a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has a structure substantially similar to that of the organic compound layer 103 shown in FIG. 1(A). In other words, the light-emitting device shown in FIG. 2 is a light-emitting device having a plurality of light-emitting units, and the light-emitting devices shown in FIGS. 1(A) to 1(C) can be said to be light-emitting devices having one light-emitting unit.

[0249] 2, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between a first electrode 501 and a second electrode 502, and an intermediate layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The first electrode 501 and the second electrode 502 correspond to the first electrode 101 and the second electrode 102 in FIG. 1(A), respectively, and the same elements as those described in the description of FIG. 1(A) can be applied to them. The first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures.

[0250] The intermediate layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied between the first electrode 501 and the second electrode 502. That is, in FIG. 2, when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, the intermediate layer 513 only needs to inject electrons into the first light-emitting unit 511 and inject holes into the second light-emitting unit 512.

[0251] The intermediate layer 513 is preferably formed to have the same structure as the charge generation layer 116 described in FIG. 1C. A composite material of an organic compound and a metal oxide has excellent carrier injection and carrier transport properties, and therefore can achieve low-voltage driving and low-current driving. Note that when the anode side surface of the light-emitting unit is in contact with the intermediate layer 513, the intermediate layer 513 can also serve as a hole injection layer for the light-emitting unit, and therefore the light-emitting unit does not need to be provided with a hole injection layer.

[0252] Furthermore, when the electron injection buffer layer 119 is provided in the intermediate layer 513, the electron injection buffer layer 119 plays the role of an electron injection layer in the light-emitting unit on the anode side, so that it is not necessarily necessary to form an electron injection layer in the light-emitting unit on the anode side.

[0253] Although FIG. 2 illustrates a light-emitting device having two light-emitting units, the present invention can be applied to a light-emitting device having three or more stacked light-emitting units. By disposing a plurality of light-emitting units between a pair of electrodes and separating them with an intermediate layer 513, as in the light-emitting device according to this embodiment, it is possible to realize a device that can emit high-luminance light while maintaining a low current density and has a long life. Furthermore, it is possible to realize a light-emitting device that can be driven at a low voltage and consumes low power. In this case, it is more preferable that the first and second light-emitting units emit light of the same hue.

[0254] Furthermore, by making the light-emitting units emit light of different hues, it is possible to obtain light of a desired color from the light-emitting device as a whole. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining light of red and green hues from the first light-emitting unit and light of blue hues from the second light-emitting unit.

[0255] The organic compound layer 103, the first light-emitting unit 511, the second light-emitting unit 512, the charge generation layer, and the electrodes can be formed by, for example, evaporation (including vacuum evaporation), droplet discharge (also called ink-jet), coating, gravure printing, etc. They may also contain low-molecular-weight materials, medium-molecular-weight materials (including oligomers and dendrimers), or polymer materials.

[0256] (Embodiment 3) In this embodiment, a display device manufactured using the light-emitting device described in Embodiments 1 and 2 will be described with reference to FIG. 3. FIG. 3A is a top view showing the display device, and FIG. 3B is a cross-sectional view taken along lines AB and CD in FIG. 3A. This display device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, for controlling light emission from the light-emitting device. 604 is a sealing substrate, 605 is a sealant, and the inside surrounded by the sealant 605 is a space 607.

[0257] The routing wiring 608 is wiring for transmitting signals input to the source line driver circuit 601 and the gate line driver circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from an FPC (flexible print circuit) 609, which serves as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. In this specification, the display device includes not only the display device itself, but also a state in which an FPC or PWB is attached to it.

[0258] Next, the cross-sectional structure will be described with reference to Fig. 3(B) . A driver circuit portion and a pixel portion are formed on an element substrate 610, but here, a source line driver circuit 601, which is the driver circuit portion, and one pixel in a pixel portion 602 are shown.

[0259] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like.

[0260] The structure of the transistors used in the pixels and the driver circuits is not particularly limited. For example, they may be inverted staggered transistors or staggered transistors. Furthermore, they may be top-gate or bottom-gate transistors. The semiconductor material used for the transistors is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and gallium nitride. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used.

[0261] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0262] Here, it is preferable to use an oxide semiconductor for the transistors provided in the pixel and the driver circuit, as well as for semiconductor devices such as transistors used in touch sensors, which will be described later. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0263] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0264] In particular, it is preferable to use, as the semiconductor layer, an oxide semiconductor film having a plurality of crystal parts whose c-axes are oriented perpendicular to the surface on which the semiconductor layer is formed or the top surface of the semiconductor layer and which does not have grain boundaries between adjacent crystal parts.

[0265] By using such a material for the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0266] Furthermore, a transistor having the above-described semiconductor layer can retain charge stored in a capacitor through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop the driver circuit while maintaining the gray level of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

[0267] To stabilize the characteristics of the transistor, it is preferable to provide an underlayer film. The underlayer film can be formed as a single layer or a multilayer using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The underlayer film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, or a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, or the like. Note that the underlayer film need not be provided if it is not necessary.

[0268] Note that FET 623 represents one of the transistors formed in the drive circuit section 601. The drive circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In addition, although this embodiment shows a driver-integrated type in which the drive circuit is formed on a substrate, this is not necessarily required, and the drive circuit may also be formed externally rather than on the substrate.

[0269] Furthermore, the pixel portion 602 is formed by a plurality of pixels each including a switching FET 611, a current control FET 612, and a first electrode 613 electrically connected to the drain of the FET, but is not limited to this, and the pixel portion may be formed by combining three or more FETs and a capacitive element.

[0270] An insulator 614 is formed to cover an end portion of the first electrode 613. Here, the insulator 614 can be formed using a positive photosensitive acrylic resin film.

[0271] Furthermore, in order to improve the coverage of an organic compound layer or the like to be formed later, a curved surface having a curvature is formed at the upper or lower end of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material for the insulator 614, it is preferable that only the upper end of the insulator 614 has a curved surface having a curvature radius (0.2 μm to 3 μm). Furthermore, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0272] An organic compound layer 616 and a second electrode 617 are formed on the first electrode 613. The first electrode 613, which functions as an anode, is preferably made of a material with a large work function. For example, a single-layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt % zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film can be used. It is also possible to use a laminated structure of a titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film. The laminated structure provides low wiring resistance, good ohmic contact, and the first electrode 613 can function as an anode.

[0273] The organic compound layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an inkjet method, or a spin coating method. The organic compound layer 616 includes the components described in Embodiments 1 and 2. Other materials constituting the organic compound layer 616 may be low-molecular-weight compounds or high-molecular-weight compounds (including oligomers and dendrimers).

[0274] Furthermore, the second electrode 617, which is formed on the organic compound layer 616 and functions as a cathode, is preferably made of a material with a small work function (such as Al, Mg, Li, or Ca, or alloys and compounds thereof (MgAg, MgIn, AlLi, etc.)). When light generated in the organic compound layer 616 is to be transmitted through the second electrode 617, the second electrode 617 is preferably made of a laminate of a thin metal thin film and a transparent conductive film (such as ITO, indium oxide containing 2 to 20 wt % zinc oxide, indium tin oxide containing silicon, or zinc oxide (ZnO)).

[0275] Note that a light-emitting device is formed with the first electrode 613, the organic compound layer 616, and the second electrode 617. The light-emitting device is the light-emitting device described in Embodiments 1 and 2. Note that a pixel portion is formed with a plurality of light-emitting devices, but the display device in this embodiment may include both the light-emitting devices described in Embodiments 1 and 2 and light-emitting devices having other structures.

[0276] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealant 605, a structure is formed in which a light-emitting device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. The space 607 is filled with a filler, which may be filled with an inert gas (nitrogen, argon, etc.) or a sealant. A recess is formed in the sealing substrate and a desiccant is provided therein, which is a preferable configuration because it can suppress deterioration due to the influence of moisture.

[0277] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as moisture and oxygen impermeable as possible. In addition, materials that can be used for the sealing substrate 604 include glass substrates, quartz substrates, and plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, etc.

[0278] Although not shown in FIG. 3, a protective film may be provided on the second electrode. The protective film may be formed of an organic resin film or an inorganic insulating film. The protective film may also be formed so as to cover the exposed portion of the sealing material 605. The protective film may also be provided so as to cover the surfaces and side surfaces of the pair of substrates, the exposed side surfaces of the sealing layer, the insulating layer, etc.

[0279] The protective film can be made of a material that is impermeable to impurities such as water, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0280] The protective film may be made of an oxide, nitride, fluoride, sulfide, ternary compound, metal, polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, or the like; a nitride containing titanium and aluminum, an oxide containing titanium and aluminum, an oxide containing aluminum and zinc, a sulfide containing manganese and zinc, a sulfide containing cerium and strontium, an oxide containing erbium and aluminum, or an oxide containing yttrium and zirconium, or the like.

[0281] The protective film is preferably formed using a film formation method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. In addition, it is possible to reduce damage to the workpiece when forming the protective film.

[0282] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on surfaces with complex uneven shapes, including the top, side, and back surfaces of a touch panel.

[0283] In this manner, a display device manufactured using the light-emitting device described in Embodiment 1 or 2 can be obtained.

[0284] The display device in this embodiment uses the light-emitting device described in Embodiment 1 or 2, and therefore, a display device with favorable characteristics can be obtained. Specifically, the light-emitting devices described in Embodiments 1 and 2 have high emission efficiency, and therefore, a display device with low power consumption can be obtained. In addition, the light-emitting devices described in Embodiments 1 and 2 have high reliability, and therefore, a display device with high reliability can be obtained.

[0285] This embodiment mode can be freely combined with other embodiment modes.

[0286] (Fourth embodiment) 4A and 4B, a display device is formed by forming a plurality of light-emitting devices 130 over an insulating layer 175. In this embodiment, a display device according to another embodiment of the present invention will be described in detail.

[0287] The display device 100 has a pixel section 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 has a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0288] In this specification and the like, when describing matters common to, for example, the subpixels 110R, 110G, and 110B, they may be referred to as the subpixels 110. When describing matters common to other components distinguished by alphabets, they may also be described using symbols without the alphabets.

[0289] The sub-pixel 110R emits red light, the sub-pixel 110G emits green light, and the sub-pixel 110B emits blue light. This allows an image to be displayed in the pixel unit 177. In this embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are described as an example, but combinations of sub-pixels of other colors may also be used. The number of sub-pixels is not limited to three, and may be four or more. Examples of four sub-pixels include sub-pixels of four colors, R, G, B, and white (W), sub-pixels of four colors, R, G, B, and Y, and sub-pixels of R, G, B, and infrared (IR).

[0290] In this specification, the row direction may be referred to as the X direction, and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0291] 4A shows an example in which sub-pixels of different colors are arranged side by side in the X direction, and sub-pixels of the same color are arranged side by side in the Y direction. Note that sub-pixels of different colors may also be arranged side by side in the Y direction, and sub-pixels of the same color may also be arranged side by side in the X direction.

[0292] A connection portion 140 may be provided outside the pixel portion 177, and a region 141 may also be provided. When the region 141 is provided, the region 141 is provided between the pixel portion 177 and the connection portion 140. When the region 141 is provided, an organic compound layer 103 is provided in the region 141. In addition, a conductive layer 151C is provided in the connection portion 140.

[0293] 4A shows an example in which the region 141 and the connection portion 140 are located on the right side of the pixel portion 177, but the positions of the region 141 and the connection portion 140 are not particularly limited. The region 141 and the connection portion 140 may be singular or plural.

[0294] Fig. 4(B) is an example of a cross-sectional view taken along dashed line A1-A2 in Fig. 4(A). As shown in Fig. 4(B), the display device 100 includes 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, the insulating layer 174, and the insulating layer 173 have openings that reach the conductive layer 172, and a plug 176 is provided to fill the opening.

[0295] In the pixel section 177, the light-emitting device 130 is provided on the insulating layer 175 and the plug 176. A cap layer 155 is provided to cover the light-emitting device 130. The substrate 120 is bonded to the cap layer 155 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.

[0296] Although multiple cross sections of the inorganic insulating layer 125 and the insulating layer 127 are shown in FIG. 4B, when the display device 100 is viewed from above, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are each connected into one.

[0297] 4(B) shows light emitting device 130R, light emitting device 130G, and light emitting device 130B. Light emitting device 130R, light emitting device 130G, and light emitting device 130B emit light of different colors. 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. Light emitting device 130R, light emitting device 130G, or light emitting device 130B may also emit other visible light or infrared light.

[0298] The display device of one embodiment of the present invention can be, for example, a top-emission type that emits light in the direction opposite to the substrate on which the light-emitting device is formed. Note that the display device of one embodiment of the present invention may also be a bottom-emission type.

[0299] The light-emitting device 130R has a first electrode 101R (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer. Note that the common layer 104 may or may not be provided, but is preferably provided because it can reduce damage to the organic compound layer 103R during processing.

[0300] The light-emitting device 130G has a first electrode 101G (pixel electrode) composed of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer. Note that the common layer 104 may or may not be provided, but is preferably provided because it can reduce damage to the organic compound layer 103G during processing.

[0301] The light-emitting device 130B has the configuration shown in Embodiments 1 and 2. It has a first electrode 101B (pixel electrode) composed of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer. Note that the common layer 104 may or may not be provided, but is preferably provided because it can reduce damage to the organic compound layer 103B during processing.

[0302] The common layer 104 is preferably an electron injection layer or an electron transport layer, more preferably an electron injection layer. When the common layer 104 is an electron transport layer, the electron transport layer preferably has a laminated structure, and it is more preferable that the layer on the second electrode side is the common layer 104 and the layer on the light-emitting layer side is the organic compound layer 103.

[0303] Furthermore, since the light emitting devices 130R and 130G are also light emitting devices fabricated through a photolithography process, the increase in drive voltage due to the photolithography process is suppressed, and the light emitting devices can be made to have a low drive voltage.

[0304] One of the pixel electrode and the common electrode of the light-emitting device 130 functions as an anode, and the other functions as a cathode. In the following description, unless otherwise specified, the pixel electrode functions as an anode and the common electrode functions as a cathode.

[0305] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are independent island-shaped layers for each light-emitting device or each emitted color. By providing the organic compound layer 103 in an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-resolution display device. This makes it possible to prevent crosstalk and realize a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0306] The island-shaped organic compound layer 103 is formed by depositing an EL film and processing the EL film using a photolithography method.

[0307] The organic compound layer 103 is preferably provided so as to cover the top and side surfaces of the first electrode (pixel electrode) of the light-emitting device 130. This makes it easier to increase the aperture ratio of the display device 100 compared to a configuration in which the end of the organic compound layer 103 is located inside the end of the pixel electrode. Furthermore, covering the side surfaces of the pixel electrode of the light-emitting device 130 with the organic compound layer 103 prevents the pixel electrode from coming into contact with the second electrode 102, thereby preventing short circuits in the light-emitting device 130.

[0308] In the display device of one embodiment of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked-layer structure. For example, in the example shown in FIG. 4B, the first electrode of the light-emitting device 130 has a stacked-layer structure of a conductive layer 151 and a conductive layer 152.

[0309] For example, a metal material can be used for 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), etc., and alloys containing appropriate combinations of these metals can also be used.

[0310] The conductive layer 152 can be formed using an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon. For example, it is preferable to use a conductive oxide containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, a work function of 4.0 eV or more, and therefore can be suitably used for the conductive layer 152.

[0311] The conductive layer 151 may have a stacked structure of multiple layers containing different materials, and the conductive layer 152 may have a stacked structure of multiple layers containing different materials. In this case, the conductive layer 151 may include a layer containing a material that can be used for the conductive layer 152, such as a conductive oxide, or the conductive layer 152 may include a layer containing a material that can be used for the conductive layer 151, such as a metal material. For example, when the conductive layer 151 has a stacked structure of two or more layers, a layer in contact with the conductive layer 152 can be a layer containing a material that can be used for the conductive layer 152.

[0312] Note that the side surfaces of the conductive layer 151 preferably have a tapered shape. Specifically, the side surfaces of the conductive layer 151 preferably have a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surfaces of the conductive layer 151 also has a tapered shape. By tapering the side surfaces of the conductive layer 152, coverage of the organic compound layer 103 provided along the side surfaces of the conductive layer 152 can be improved.

[0313] Next, an example of a method for manufacturing the display device 100 having the structure shown in FIG. 4A will be described with reference to FIGS.

[0314] [Production method example 1] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum deposition method, a pulsed laser deposition (PLD) method, an ALD method, etc.

[0315] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by wet film formation methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0316] Furthermore, when processing the thin films that constitute the display device, they can be processed using, for example, photolithography.

[0317] In photolithography, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure may also be performed using immersion exposure techniques. Extreme ultraviolet (EUV) light or X-rays may also be used as light for exposure. An electron beam may also be used instead of light for exposure.

[0318] The thin film can be etched by dry etching, wet etching, sandblasting, or the like.

[0319] 5A, an insulating layer 171 is formed on a substrate (not shown). Subsequently, conductive layers 172 and 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 so as to cover the conductive layers 172 and 179. Subsequently, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0320] The substrate may be a substrate having heat resistance sufficient to withstand at least the subsequent heat treatment, such as a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate made of silicon germanium, or an SOI substrate.

[0321] Subsequently, openings are formed in the insulating layers 175, 174, and 173, reaching the conductive layer 172. Subsequently, plugs 176 are formed so as to fill the openings.

[0322] Subsequently, a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, is formed on the plugs 176 and the insulating layer 175. The conductive film 151f may be made of, for example, a metal material.

[0323] Subsequently, a resist mask 191 is formed over the conductive film 151f. The resist mask 191 can be formed by applying a photosensitive material (photoresist), exposing it to light, and developing it.

[0324] 5B, for example, the conductive film 151f is removed from a region that does not overlap with the resist mask 191. In this way, the conductive layer 151 is formed.

[0325] 5(C), the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, for example.

[0326] Next, as shown in FIG. 5(D), an insulating film 156f, which will later become insulating layers 156R, 156G, 156B, and 156C, is formed on the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, the conductive layer 151C, and the insulating layer 175.

[0327] The insulating film 156f can be an inorganic insulating film such as an insulating oxide film, an insulating nitride film, an insulating oxynitride film, or an insulating nitride oxide film, for example, a silicon oxynitride film.

[0328] Subsequently, as shown in FIG. 5(E), the insulating film 156f is processed to form an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C.

[0329] 6(A), the EL film 103Rf is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the insulating layer 175. Note that, as shown in FIG. 6(A), the EL film 103Rf is not formed on the conductive layer 152C.

[0330] Subsequently, as shown in FIG. 6(A), a sacrificial film 158Rf and a mask film 159Rf are formed.

[0331] By providing the sacrificial film 158Rf on the EL film 103Rf, damage to the EL film 103Rf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0332] The sacrificial film 158Rf is made of a film that is highly resistant to the processing conditions of the EL film 103Rf, specifically, a film that has a large etching selectivity with respect to the EL film 103Rf.The mask film 159Rf is made of a film that has a large etching selectivity with respect to the sacrificial film 158Rf.

[0333] The sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat-resistant temperature of the EL film 103Rf. The substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf is typically 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, more preferably 100°C or lower, and even more preferably 80°C or lower.

[0334] It is preferable to use a film that can be removed by wet etching for the sacrificial film 158Rf and the mask film 159Rf.

[0335] The sacrificial film 158Rf formed on and in contact with the EL film 103Rf is preferably formed using a method that causes less damage to the EL film 103Rf than the mask film 159Rf. For example, the ALD method or the vacuum deposition method is more preferable than the sputtering method.

[0336] The sacrificial film 158Rf and the mask film 159Rf may each be made of one or more of a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, an inorganic insulating film, or the like.

[0337] The sacrificial film 158Rf and the mask film 159Rf can be made of metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metal materials. It is particularly preferable to use a low-melting-point material such as aluminum or silver. Using a metal material capable of blocking ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf is preferable because it can prevent ultraviolet rays from being irradiated onto the EL film 103Rf and suppress deterioration of the EL film 103Rf.

[0338] Furthermore, for the sacrificial film 158Rf and the mask film 159Rf, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), and indium tin oxide containing silicon can be used, respectively.

[0339] In addition, in the above metal oxide, an element M (wherein M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used instead of gallium.

[0340] The sacrificial film 158Rf and the mask film 159Rf are preferably made of a semiconductor material such as silicon or germanium, which has a high affinity with the semiconductor manufacturing process, or a compound containing the semiconductor material.

[0341] Moreover, various inorganic insulating films can be used for the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, an oxide insulating film is preferable because it has higher adhesion to the EL film 103Rf than a nitride insulating film.

[0342] 6(A), a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and then exposing and developing it.

[0343] The resist mask 190R is provided in a position overlapping with the conductive layer 152R. The resist mask 190R is preferably provided also in a position overlapping with the conductive layer 152C, which can prevent the conductive layer 152C from being damaged during the manufacturing process of the display device.

[0344] 6(B), a resist mask 190R is used to remove a portion of the mask film 159Rf to form a mask layer 159R. The mask layer 159R remains on the conductive layer 152R and the conductive layer 152C. The resist mask 190R is then removed. The mask layer 159R is used as a mask (also referred to as a hard mask) to remove a portion of the sacrificial film 158Rf to form a sacrificial layer 158R.

[0345] By using the wet etching method, damage to the EL film 103Rf during processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to when using the dry etching method. When using the wet etching method, it is preferable to use a chemical solution such as a developer, a tetramethylammonium hydroxide solution (TMAH), diluted hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0346] Furthermore, when dry etching is used to process the sacrificial film 158Rf, deterioration of the EL film 103Rf can be suppressed by not using a gas containing oxygen as the etching gas.

[0347] The resist mask 190R can be removed in the same manner as the resist mask 191.

[0348] 6(B), the EL film 103Rf is processed to form the organic compound layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove a part of the EL film 103Rf, thereby forming the organic compound layer 103R.

[0349] 6B, a stacked structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. Also, the conductive layers 152G and 152B are exposed.

[0350] The EL film 103Rf is preferably processed by anisotropic etching, particularly anisotropic dry etching, or wet etching may be used.

[0351] When dry etching is used, deterioration of the EL film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0352] Alternatively, an etching gas containing oxygen may be used. The etching rate can be increased by using an etching gas containing oxygen. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate. This reduces damage to the EL film 103Rf. Furthermore, problems such as adhesion of reaction products generated during etching can be reduced.

[0353] When dry etching is used, it is preferable to use a gas containing one or more of H, CF, C, F, SF, CHF, Cl, H, O, BCl, or Group 18 elements such as He and Ar as the etching gas. Alternatively, it is preferable to use a gas containing one or more of these elements and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas.

[0354] Subsequently, as shown in FIG. 7(A), an EL film 103Gf, which will later become the organic compound layer 103G, is formed.

[0355] The EL film 103Gf can be formed by the same method as that used to form the EL film 103Rf, and can have the same structure as the EL film 103Rf.

[0356] Next, a sacrificial film 158Gf and a mask film 159Gf are formed in this order. Then, a resist mask 190G is formed in a position overlapping the conductive layer 152G. The materials and forming methods of the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and forming methods of the resist mask 190G are the same as those applicable to the resist mask 190R.

[0357] 7(B), a resist mask 190G is used to remove a portion of the mask film 159Gf to form a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. The resist mask 190G is then removed. Next, using the mask layer 159G as a mask, a portion of the sacrificial film 158Gf is removed to form a sacrificial layer 158G. Next, the EL film 103Gf is processed to form an organic compound layer 103G.

[0358] 7(C), the EL film 103Bf is formed. The EL film 103Bf can be formed by the same method as that used to form the EL film 103Rf. The EL film 103Bf can have the same structure as the EL film 103Rf.

[0359] 7(C), a sacrificial film 158Bf and a mask film 159Bf are formed in this order. Then, a resist mask 190B is formed at a position overlapping the conductive layer 152B. The materials and forming methods of the sacrificial film 158Bf and the mask film 159Bf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and forming methods of the resist mask 190B are the same as those applicable to the resist mask 190R.

[0360] 7(D), a resist mask 190B is used to remove a portion of the mask film 159Bf to form a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. The resist mask 190B is then removed. The mask layer 159B is then used as a mask to remove a portion of the sacrificial film 158Bf to form a sacrificial layer 158B. The EL film 103Bf is then processed to form the organic compound layer 103B. For example, the mask layer 159B and the sacrificial layer 158B are used as hard masks to remove a portion of the EL film 103Bf to form the organic compound layer 103B.

[0361] As a result, a laminated structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B, and the mask layers 159R and 159G are exposed.

[0362] It is preferable that the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are perpendicular or approximately perpendicular to the surface on which they are formed. For example, it is preferable that the angle formed between the surface on which they are formed and these side surfaces is 60 degrees or more and 90 degrees or less.

[0363] As described above, the distance between adjacent pairs of the organic compound layers 103R, 103G, and 103B formed using photolithography can be reduced to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, the distance can be defined, for example, as the distance between the opposing ends of adjacent pairs of the organic compound layers 103R, 103G, and 103B. By reducing the distance between the island-shaped organic compound layers in this manner, a display device with high definition and a large aperture ratio can be provided. Furthermore, the distance between the first electrodes of adjacent light-emitting devices can also be reduced, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. For example, by using an exposure tool for LSIs, the spacing can be narrowed to 500 nm or less, 200 nm or less, 100 nm or less, or even 50 nm or less.

[0364] Subsequently, as shown in FIG. 8(A), it is preferable to remove the mask layers 159R, 159G, and 159B.

[0365] The mask layer removal process can be performed using the same method as the mask film processing process. In particular, by using a wet etching method, damage to the organic compound layer 103 during the mask layer removal can be reduced compared to when a dry etching method is used.

[0366] The mask layer may also be removed by dissolving it in a solvent such as water or alcohol, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0367] After removing the mask layer, a drying treatment may be performed to remove water adsorbed on the surface. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. A reduced pressure atmosphere is preferred because it allows drying at a lower temperature.

[0368] Subsequently, as shown in FIG. 8(B), an inorganic insulating film 125f is formed.

[0369] Subsequently, as shown in FIG. 8(C), an insulating film 127f, which will later become the insulating layer 127, is formed on the inorganic insulating film 125f.

[0370] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0371] As the inorganic insulating film 125f, it is preferable to form an insulating film having a thickness of 3 nm or more, 5 nm or more, or 10 nm or more, and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above substrate temperature range.

[0372] The inorganic insulating film 125f is preferably formed by, for example, the ALD method. The ALD method is preferable because it can reduce film formation damage and also allows for the formation of a film with high coverage. The inorganic insulating film 125f is preferably formed as an aluminum oxide film by, for example, the ALD method.

[0373] The insulating film 127f is preferably formed by the wet film formation method described above. The insulating film 127f is preferably formed by, for example, spin coating using a photosensitive material, more specifically, using a photosensitive resin composition containing an acrylic resin.

[0374] Subsequently, exposure is performed to expose a part of the insulating film 127f to visible light or ultraviolet light. The insulating layer 127 is formed in a region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C.

[0375] The exposed region of the insulating film 127f can control the width of the insulating layer 127 to be formed later. In this embodiment, the insulating layer 127 is processed so as to have a portion overlapping the upper surface of the conductive layer 151.

[0376] The light used for exposure preferably contains i-line (wavelength 365 nm), and may contain at least one of g-line (wavelength 436 nm) and h-line (wavelength 405 nm).

[0377] Subsequently, as shown in FIG. 9(A), development is carried out to remove the exposed area of ​​the insulating film 127f, thereby forming the insulating layer 127a.

[0378] 9(B), an etching process is performed using the insulating layer 127a as a mask to remove a portion of the inorganic insulating film 125f and reduce the thickness of a portion of the sacrificial layers 158R, 158G, and 158B. As a result, the inorganic insulating layer 125 is formed below the insulating layer 127a. Furthermore, the surfaces of the thin portions of the sacrificial layers 158R, 158G, and 158B are exposed. Note that, hereinafter, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0379] The first etching process can be performed by dry etching or wet etching. Note that, when the inorganic insulating film 125f is formed using the same material as the sacrificial layers 158R, 158G, and 158B, the first etching process can be performed all at once, which is preferable.

[0380] When dry etching is performed, it is preferable to use a chlorine-based gas. Examples of chlorine-based gases that can be used include Cl2, BCl3, SiCl4, and CCl4, either singly or in combination. Furthermore, oxygen gas, hydrogen gas, helium gas, and argon gas can be added to the chlorine-based gas, either singly or in combination. By using dry etching, thin-film regions of the sacrificial layers 158R, 158G, and 158B can be formed with good in-plane uniformity.

[0381] The dry etching apparatus may be a dry etching apparatus having a high-density plasma source, such as an inductively coupled plasma (ICP) etching apparatus, or a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes.

[0382] The first etching process is preferably performed by wet etching. The wet etching method can reduce damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B compared to the dry etching method. For example, the wet etching can be performed using an alkaline solution or an acid solution.

[0383] In the first etching process, it is preferable to stop the etching process when the film thicknesses of the sacrificial layers 158R, 158G, and 158B have become thin without completely removing them. In this way, by leaving the sacrificial layers 158R, 158G, and 158B on the organic compound layers 103R, 103G, and 103B, it is possible to prevent the organic compound layers 103R, 103G, and 103B from being damaged in subsequent processing steps.

[0384] Next, the entire substrate is exposed to visible light or ultraviolet light, and the insulating layer 127a is preferably irradiated with the energy density of 0 mJ / cm. 2 Larger, 800mJ / cm 2 It is preferable that the dose is 0 mJ / cm or less, and 2 Larger, 500mJ / cm 2 It is more preferable to perform the following. By performing such exposure after development, the transparency of the insulating layer 127a can be improved in some cases. Furthermore, the substrate temperature required for heat treatment to transform the insulating layer 127a into a tapered shape in a later step can be reduced in some cases.

[0385] Here, the presence of a barrier insulating layer against oxygen (e.g., an aluminum oxide film, etc.) as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can reduce the diffusion of oxygen into the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B.

[0386] Next, heat treatment (also referred to as post-baking) is performed. By performing the heat treatment, the insulating layer 127a can be transformed into the insulating layer 127 having tapered side surfaces (FIG. 9C). The heat treatment is performed at a temperature lower than the upper temperature limit of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., more preferably 70° C. to 130° C. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. The heating atmosphere may be an atmospheric pressure atmosphere or a reduced-pressure atmosphere. This can improve adhesion between the insulating layer 127 and the inorganic insulating layer 125 and also improve the corrosion resistance of the insulating layer 127.

[0387] By not completely removing the sacrificial layers 158R, 158G, and 158B in the first etching process and leaving the sacrificial layers 158R, 158G, and 158B in a thinner state, the organic compound layers 103R, 103G, and 103B can be prevented from being damaged and deteriorated in the heat treatment, thereby improving the reliability of the light-emitting device.

[0388] 10(A), an etching process is performed using the insulating layer 127 as a mask to remove portions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, openings are formed in the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, respectively, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Note that, hereinafter, this etching process may be referred to as a second etching process.

[0389] The end of the inorganic insulating layer 125 is covered with the insulating layer 127. Also, Fig. 10(A) shows an example in which part of the end of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered with the insulating layer 127, and the tapered portion formed by the second etching process is exposed.

[0390] The second etching process is performed by wet etching. By using the wet etching method, damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to when using the dry etching method. The wet etching can be performed using, for example, an alkaline solution or an acid solution.

[0391] 10B, a second electrode (common electrode) 102 is formed on the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the conductive layer 152C, and the insulating layer 127. The second electrode (common electrode) 102 can be formed by a method such as sputtering or vacuum deposition.

[0392] 10(C), a cap layer 155 is formed on the second electrode (common electrode) 102. The cap layer 155 can be formed by a method such as a vacuum deposition method, a sputtering method, a CVD method, or an ALD method.

[0393] Subsequently, the substrate 120 is attached over the cap layer 155 using the resin layer 122, whereby a display device can be manufactured. As described above, in the method for manufacturing a display device of one embodiment of the present invention, the insulating layer 156 is provided so as to have a region overlapping with a side surface of the conductive layer 151, and the conductive layer 152 is formed so as to cover the conductive layer 151 and the insulating layer 156. This can increase the yield of the display device and suppress the occurrence of defects.

[0394] As described above, in the manufacturing method of the display device according to this embodiment, the island-shaped organic compound layers 103R, 103G, and 103B are formed not using a fine metal mask but by forming a film over the entire surface and then processing it by photolithography. This allows the island-shaped layers to be formed with a uniform thickness. Furthermore, a high-resolution display device or a display device with a high aperture ratio can be realized. Even if the resolution or aperture ratio is high and the distance between subpixels is extremely short, the organic compound layers 103R, 103G, and 103B can be prevented from contacting each other in adjacent subpixels. Therefore, leakage current between subpixels can be suppressed. This prevents crosstalk and realizes a display device with extremely high contrast. Furthermore, a display device with excellent characteristics can be provided, even in a display device having tandem light-emitting devices manufactured using photolithography.

[0395] (Embodiment 5) In this embodiment, a display device according to one embodiment of the present invention will be described.

[0396] The display device of the present embodiment can be a high-definition display device, and can therefore be used as a display unit for information terminals (wearable devices) such as wristwatches and bracelets, as well as 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.

[0397] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0398] [Display module] 11A shows a perspective view of a 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, and may be any of the display devices 100B to 100E2 described below.

[0399] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 (described later) can be viewed.

[0400] 11(B) is a perspective view schematically showing the configuration on the substrate 291 side. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. A terminal portion 285 for connecting to an FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0401] The pixel section 284 has a plurality of periodically arranged pixels 284a. An enlarged view of one pixel 284a is shown on the right side of Fig. 11(B). The various configurations described in the previous embodiments can be applied to the pixel 284a.

[0402] The pixel circuit section 283 has a plurality of pixel circuits 283a arranged periodically.

[0403] One pixel circuit 283a is a circuit that controls the driving of a plurality of elements included in one pixel 284a.

[0404] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0405] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit section 282. An IC may be mounted on the FPC 290.

[0406] The display module 280 can be configured such that one or both of the pixel circuit unit 283 and the circuit unit 282 are stacked below the pixel unit 284, thereby making it possible to extremely increase the aperture ratio (effective display area ratio) of the display unit 281.

[0407] Such a display module 280 has extremely high resolution and can therefore be suitably used in VR devices such as HMDs or glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through lenses, the display module 280 has an extremely high-resolution display unit 281, so that even if the display unit is enlarged with the lenses, the pixels are not visible, allowing for 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 units.

[0408] [Display device 100A] The display device 100A shown in FIG. 12A 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.

[0409] The substrate 301 corresponds to the substrate 291 in FIGS. 11A and 11B. The transistor 310 has a channel formation region in the substrate 301. The substrate 301 can be, for example, a semiconductor substrate such as a single crystal silicon substrate. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0410] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0411] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0412] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 located therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0413] The conductive layer 241 is provided over the insulating layer 261 and is buried in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 by a plug 271 buried in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0414] An insulating layer 255 is provided to cover the capacitor 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0415] An insulating layer 156R is provided to have a region overlapping with a side surface of the conductive layer 151R, an insulating layer 156G is provided to have a region overlapping with a side surface of the conductive layer 151G, and an insulating layer 156B is provided to have a region overlapping with a side surface of the conductive layer 151B. Furthermore, a conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided 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.

[0416] The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B are electrically connected to one of the source and drain of the transistor 310 via an insulating layer 243, an insulating layer 255, an insulating layer 174, a plug 256 embedded in the insulating layer 175, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the plug.

[0417] Furthermore, a cap layer 155 is provided on the light-emitting devices 130R, 130G, and 130B. A substrate 120 is bonded to the cap layer 155 by a resin layer 122. For details of the components from the light-emitting devices 130 to the substrate 120, refer to Embodiment 4. The substrate 120 corresponds to the substrate 292 in FIG. 11(A).

[0418] Fig. 12(B) is a modified example of the display device 100A shown in Fig. 12(A). The display device shown in Fig. 12(B) has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has an area where it overlaps with one of the colored layer 132R, the colored layer 132G, and the colored layer 132B. In the display device shown in Fig. 12(B), the light-emitting device 130 can emit, for example, white light. Furthermore, 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.

[0419] [Display device 100B] FIG. 13 shows a perspective view of the display device 100B, and FIG. 14 shows a cross-sectional view of the display device 100C.

[0420] The display device 100B has a configuration in which a substrate 352 and a substrate 351 are bonded together. In Fig. 13, the substrate 352 is indicated by a dashed line.

[0421] The display device 100B has a pixel portion 177, a connection portion 140, a circuit 356, wiring 355, etc. Fig. 13 shows an example in which an IC 354 and an FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Fig. 13 can also be called a display module having the display device 100B, an IC (integrated circuit), and an FPC. Here, a display device having a connector such as an FPC attached to a substrate, or a display device having an IC mounted on the substrate, is called a display module.

[0422] The connection section 140 is provided outside the pixel section 177. There may be one or more connection sections 140. The connection section 140 electrically connects the common electrode of the light-emitting device and the conductive layer, and can supply a potential to the common electrode.

[0423] The circuit 356 can be, for example, a scanning line driver circuit.

[0424] The wiring 355 has a function of supplying signals and power to the pixel portion 177 and the circuit 356. The signals and power are input to the wiring 355 from the outside via the FPC 353 or from the IC 354.

[0425] 13 shows an example in which an IC 354 is provided on a substrate 351 by a COG (Chip On Glass) method or a COF (Chip On Film) method. The IC 354 may be, for example, an IC having a scanning line driver circuit or a signal line driver circuit. The display device 100B and the display module may not include an IC. Alternatively, the IC may be mounted on an FPC by, for example, a COF method.

[0426] Figure 14 shows an example of a cross section of the display device 100B in Figure 13, where part of the area including the FPC 353, part of the circuit 356, part of the pixel section 177, part of the connection section 140, and part of the area including the end portion are cut away, as display device 100C.

[0427] [Display device 100C] The display device 100C shown in Figure 14 has, between a substrate 351 and a substrate 352, a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc.

[0428] For details of the light emitting devices 130R, 130G, and 130B, see the fourth embodiment.

[0429] Light-emitting device 130R has conductive layer 224R, conductive layer 151R on conductive layer 224R, and conductive layer 152R on conductive layer 151R. Light-emitting device 130G has conductive layer 224G, conductive layer 151G on conductive layer 224G, and conductive layer 152G on conductive layer 151G. Light-emitting device 130B has conductive layer 224B, conductive layer 151B on conductive layer 224B, and conductive layer 152B on conductive layer 151B.

[0430] The conductive layer 224R is connected to the conductive layer 222b of the transistor 205 through an opening provided in the insulating layer 214. An end of the conductive layer 151R is located outside an end of the conductive layer 224R. An insulating layer 156R is provided to have a region in contact with a side surface of the conductive layer 151R, and a conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R.

[0431] Conductive layer 224G, conductive layer 151G, conductive layer 152G, and insulating layer 156G in light-emitting device 130G, and conductive layer 224B, conductive layer 151B, conductive layer 152B, and insulating layer 156B in light-emitting device 130B are similar to conductive layer 224R, conductive layer 151R, conductive layer 152R, and insulating layer 156R in light-emitting device 130R, and therefore detailed description thereof will be omitted.

[0432] Recesses are formed in the conductive layers 224R, 224G, and 224B so as to cover the openings provided in the insulating layer 214. A layer 128 is buried in the recesses.

[0433] Layer 128 has the function of filling in recesses in conductive layer 224R, conductive layer 224G, and conductive layer 224B and planarizing the surface. Conductive layers 151R, 151G, and 151B, which are electrically connected to conductive layer 224R, conductive layer 224G, and conductive layer 224B, are provided on conductive layer 224R, conductive layer 224G, and conductive layer 224B and layer 128. Therefore, the regions overlapping with the recesses in conductive layer 224R, conductive layer 224G, and conductive layer 224B can also be used as light-emitting regions, thereby increasing the aperture ratio of the pixel.

[0434] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be used for the layer 128 as appropriate. In particular, the layer 128 is preferably formed using an insulating material, and is particularly preferably formed using an organic insulating material. For example, the organic insulating materials that can be used for the insulating layer 127 described above can be used for the layer 128.

[0435] A cap layer 155 is provided on the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B. The cap layer 155 and the substrate 352 are bonded via an adhesive layer 142. A light-shielding layer 157 is provided on the substrate 352. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light-emitting device 130. In FIG. 14, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (nitrogen, argon, etc.), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light-emitting device. Alternatively, the space may be filled with a resin different from the frame-shaped adhesive layer 142.

[0436] 14 shows an example in which connecting portion 140 has conductive layer 224C obtained by processing the same conductive film as conductive layers 224R, 224G, and 224B, conductive layer 151C obtained by processing the same conductive film as conductive layers 151R, 151G, and 151B, and conductive layer 152C obtained by processing the same conductive film as conductive layers 152R, 152G, and 152B. Also shown in FIG. 14 is an example in which insulating layer 156C is provided so as to have a region overlapping with a side surface of conductive layer 151C.

[0437] The display device 100C is a top-emission type. Light emitted by the light-emitting device is emitted toward the substrate 352. The substrate 352 is preferably made of a material that is highly transparent to visible light. The pixel electrode contains a material that reflects visible light, and the counter electrode (common electrode) contains a material that transmits visible light.

[0438] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over the substrate 351 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistor. The insulating layer 214 is provided to cover the transistor and functions as a planarization layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0439] The insulating layers 211, 213, and 215 are each preferably formed using an inorganic insulating film.

[0440] The insulating layer 214, which functions as a planarizing layer, is preferably an organic insulating layer.

[0441] The transistor 201 and the transistor 205 each include a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a conductive layer 222a and a conductive layer 222b functioning as a source and a drain, a semiconductor layer 231, an insulating layer 213 functioning as a gate insulating layer, and a conductive layer 223 functioning as a gate.

[0442] A connection portion 204 is provided in a region of the substrate 351 where the substrate 352 does not overlap. In the connection portion 204, a source electrode or a drain electrode of the transistor 201 is electrically connected to the FPC 353 via a conductive layer 166 and a connection layer 242. The conductive layer 166 has an example of a stacked structure including a conductive film obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. The conductive layer 166 is exposed on the top surface of the connection portion 204. This allows the connection portion 204 and the FPC 353 to be electrically connected via the connection layer 242.

[0443] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 facing the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, on the connection section 140, on the circuit 356, etc. Also, various optical members can be arranged on the outside of the substrate 352.

[0444] The substrate 351 and the substrate 352 can be made of the same material as can be used for the substrate 120 .

[0445] The adhesive layer 142 can be made of a material that can be used for the resin layer 122 .

[0446] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0447] [Display device 100D] The display device 100D shown in FIG. 15 differs from the display device 100C shown in FIG. 14 mainly in that it is a bottom-emission display device.

[0448] Light emitted from the light emitting device is emitted toward the substrate 351. It is preferable that a material with high transparency to visible light is used for the substrate 351. On the other hand, the light transparency of the material used for the substrate 352 is not an issue.

[0449] A light-shielding layer 317 is preferably formed between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205. Figure 15 shows an example in which the light-shielding layer 317 is provided over the substrate 351, the insulating layer 153 is provided over the light-shielding layer 317, and the transistors 201, 205, etc. are provided over the insulating layer 153.

[0450] Light emitting device 130R includes conductive layer 112R, conductive layer 126R on conductive layer 112R, and conductive layer 129R on conductive layer 126R.

[0451] Light emitting device 130B includes conductive layer 112B, conductive layer 126B on conductive layer 112B, and conductive layer 129B on conductive layer 126B.

[0452] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are each made of a material that is highly transparent to visible light. The second electrode 102 is preferably made of a material that reflects visible light.

[0453] Although the light emitting device 130G is not shown in FIG. 15, the light emitting device 130G is also provided.

[0454] Although FIG. 15 and other figures show an example in which the top surface of the layer 128 has a flat portion, the shape of the layer 128 is not particularly limited.

[0455] [Display device 100D2] The display device 100D2 shown in Fig. 16(A) is an example of a bottom-emission display device that differs from the display device 100D shown in Fig. 15. The display device 100D2 differs from the display device 100D in that it has an organic resin layer 180. Note that in the drawing, the reference numerals of the same components as those in Fig. 15 may be omitted, and the description in Fig. 15 may be referred to for details.

[0456] 16(B) shows a top view layout of pixel 178 (pixel 178a and pixel 178b) having subpixels 110 (subpixels 110R, 110G, 110B, and 110W), and FIG. 16(C) shows a top view of organic resin layer 180 in a region where subpixels 110R and 110G of pixel 178 are formed. Note that the distance between light-shielding layers 317 is width 110Rw in the light-emitting region of subpixel 110R.

[0457] As shown in FIG. 16(A), the organic resin layer 180 is provided on the insulating layer 214. As shown in the region surrounded by the dashed dotted line in FIG. 16(A) and in FIG. 16(C), the organic resin layer 180 has curved recesses 181 (recesses 181a and 181b) at least in the region where the subpixels are formed. The recesses 181 may be provided outside the light-emitting region, such as recess 181c. By providing recess 181c, light emitted in the region overlapping with the light-shielding layer 317 or light traveling to the region overlapping with the light-shielding layer 317 is refracted and can be extracted from the light-emitting region, thereby improving the light-emitting efficiency.

[0458] A plurality of recesses 181 may be formed in a matrix. Recesses 181a and 181b may be provided in contact with each other, or may have a flat surface between them.

[0459] 16, the recess has a hexagonal top surface shape (FIG. 16(C)) and a semicircular cross-sectional shape (FIG. 16(A)), but other shapes may be used as needed. For example, the recess may have a polygonal top surface shape such as a triangle, a quadrangle (including a rectangle and a square), a pentagon, or any of these polygons with rounded corners, an ellipse, or a circle.

[0460] An insulating layer containing an organic material can be used as the organic resin layer 180. For example, acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, precursors of these resins, etc. can be used as the organic resin layer 180. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin can be used as the organic resin layer 180.

[0461] Furthermore, a photosensitive resin can be used as the organic resin layer 180. A photoresist can be used as the photosensitive resin. The photosensitive resin can be a positive-type material or a negative-type material.

[0462] The organic resin layer 180 may contain a material that absorbs visible light. For example, the organic resin layer 180 itself may be made of a material that absorbs visible light, or the organic resin layer 180 may contain a pigment that absorbs visible light. For example, the organic resin layer 180 may be made of 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.

[0463] In addition, a first electrode 101 (a first electrode 101R and a first electrode 101W) is provided on the organic resin layer 180, and an organic compound layer 103 is provided on the first electrode 101. Ends of the first electrode 101 and the organic compound layer 103 may be covered with an insulating layer 127.

[0464] Furthermore, the first electrode 101 formed on the organic resin layer 180 has a recess similar to the recess of the organic resin layer 180. Furthermore, the organic compound layer 103 formed on the first electrode 101 has a recess similar to the recess of the first electrode 101. Furthermore, the common layer 104 formed on the organic compound layer 103 has a recess similar to the recess of the organic compound layer 103. Furthermore, the second electrode 102 formed on the common layer 104 has a recess similar to 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 in which they overlap one another.

[0465] In addition, a common layer 104 is provided over the organic compound layer 103 and the insulating layer 127, and a second electrode 102 is provided over the common layer 104. A cap layer 155 is provided over the second electrode 102, and the second electrode 102 is bonded to a substrate 352 via an adhesive layer 142.

[0466] Although FIG. 16A shows only light emitting device 130W and light emitting device 130R and does not show light emitting device 130G and light emitting device 130B, light emitting device 130G and light emitting device 130B are also provided.

[0467] The above-described light-emitting device according to one embodiment of the present invention can provide an organic semiconductor device with high emission efficiency, and therefore, an organic semiconductor device with high reliability, low driving voltage, and low power consumption can be provided.

[0468] [Display device 100E] The display device 100E shown in FIG. 17 is a modification of the display device 100C shown in FIG. 14, and differs from the display device 100C mainly in that it has colored layers 132R, 132G, and 132B.

[0469] In the display device 100E, the light-emitting device 130 has an area that overlaps one of the colored layer 132R, the colored layer 132G, and the colored layer 132B. The colored layer 132R, the colored layer 132G, and the colored layer 132B can be provided on the surface of the substrate 352 facing the substrate 351. An end of the colored layer 132R, an end of the colored layer 132G, and an end of the colored layer 132B can overlap the light-shielding layer 157.

[0470] In the display device 100E, the light-emitting device 130 can emit, for example, white light. Furthermore, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may be configured such that the colored layers 132R, 132G, and 132B are provided between the cap layer 155 and the adhesive layer 142.

[0471] [Display device 100E2] The display device 100E2 shown in Fig. 18(A) is a modified example of the display device 100E shown in Fig. 17, and has microlenses 182 on the colored layers 132R, 132G, and 132B. Note that in the drawing, the reference numerals of the same components as those in Fig. 17 may be omitted, and the description in Fig. 17 may be referred to for details.

[0472] 18(B) shows a top view layout of a pixel 178 (pixel 178a and pixel 178b) having subpixels 110 (subpixels 110R, 110G, and 110B), and FIG. 18(C) shows a top view of a microlens 182 in a region where the subpixels 110R and 110G of the pixel 178 are formed. The region where the common electrode and the organic compound layer 103 are in contact has a width 110Gw in the light-emitting region of the subpixel 110G.

[0473] 18(A) has a planarization film 143 on a cap layer 155, and colored layers 132R, 132G, and 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.

[0474] As shown in FIG. 18C, the microlens 182 may be provided for each sub-pixel in a region where the sub-pixel is formed.

[0475] 18(C), the top surface shape of the microlens 182 is shown as a hexagon, but other shapes may be used as needed. For example, the top surface shape of the microlens 182 may be a polygon such as a triangle, a quadrangle (including a rectangle and a square), a pentagon, or any of these polygons with rounded corners, an ellipse, or a circle.

[0476] The microlenses 182 can be formed using the same material as the organic resin layer 180 .

[0477] The light-emitting device of one embodiment of the present invention having the above-described microlens 182 includes a capping layer as described in Embodiment 1. Therefore, an organic semiconductor device with high emission efficiency can be provided due to the effect of the microlens 182 and the effect of the organic semiconductor device using the capping layer being inseparable as an integrated unit. Therefore, an organic semiconductor device with good reliability, low driving voltage, and low power consumption that is optimal for a mobile display can be provided.

[0478] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when multiple configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0479] (Embodiment 6) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0480] The electronic devices of this embodiment include the display device of one embodiment of the present invention in a display portion. The display device of one embodiment of the present invention has low power consumption and high reliability. Therefore, the display device of one embodiment of the present invention can be used in the display portion of various electronic devices.

[0481] Examples of electronic devices include electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound playback devices.

[0482] An example of a wearable device that can be worn on the head will be described with reference to FIGS. 19(A) to 19(D).

[0483] The electronic device 700A shown in Figure 19(A) and the electronic device 700B shown in Figure 19(B) each have a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0484] The display device of one embodiment of the present invention can be applied to the display panel 751. Therefore, the electronic device can be highly reliable.

[0485] The electronic device 700A and the electronic device 700B can each project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Because the optical member 753 is translucent, the user can see the image displayed in the display area superimposed on a transmitted image visible through the optical member 753.

[0486] Electronic device 700A and electronic device 700B may be provided with a camera capable of capturing an image in front of them as an imaging unit. Furthermore, electronic device 700A and electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to that orientation in display area 756.

[0487] The communication unit has a wireless communication device, and can supply, for example, a video signal via the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential can be connected may be provided.

[0488] Furthermore, the electronic device 700A and the electronic device 700B are provided with batteries, which can be charged wirelessly and / or by wire.

[0489] The housing 721 may be provided with a touch sensor module.

[0490] Various touch sensors can be used as the touch sensor module. For example, various types of touch sensors can be used, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, or an optical type. In particular, it is preferable to use a capacitance type or an optical type sensor in the touch sensor module.

[0491] The electronic device 800A shown in Figure 19(C) and the electronic device 800B shown in Figure 19(D) each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0492] The display device of one embodiment of the present invention can be applied to the display portion 820. Therefore, the electronic device can be highly reliable.

[0493] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform a three-dimensional display using parallax.

[0494] It is preferable that electronic device 800A and electronic device 800B each have a mechanism that allows the left and right positions of lens 832 and display unit 820 to be adjusted so that they are optimally positioned according to the position of the user's eyes.

[0495] The wearing part 823 allows the user to wear the electronic device 800A or the electronic device 800B on the head.

[0496] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. Furthermore, multiple cameras may be provided to support multiple angles of view, such as telephoto and wide angle.

[0497] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone.

[0498] The electronic device 800A and the electronic device 800B may each have an input terminal to which a cable can be connected for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0499] The electronic device of one embodiment of the present invention may have a function of wirelessly communicating with the earphone 750.

[0500] 19B includes an earphone unit 727. A part of the wiring connecting the earphone unit 727 and a control unit may be disposed inside the housing 721 or the attachment unit 723.

[0501] 19(D) includes an earphone unit 827. For example, the earphone unit 827 and the control unit 824 can be configured to be connected to each other by wire.

[0502] As described above, the electronic devices of one embodiment of the present invention are preferably either glasses-type devices (such as the electronic devices 700A and 700B) or goggle-type devices (such as the electronic devices 800A and 800B).

[0503] An electronic device 6500 shown in FIG. 20A is a portable information terminal that can be used as a smartphone.

[0504] The electronic device 6500 includes a housing 6501, a display portion 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, and a light source 6508. The display portion 6502 has a touch panel function.

[0505] The display device of one embodiment of the present invention can be applied to the display portion 6502. Therefore, the electronic device can be highly reliable.

[0506] FIG. 20B is a schematic cross-sectional view including the end portion of the housing 6501 on the microphone 6506 side.

[0507] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0508] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by adhesive layers (not shown).

[0509] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0510] The display device of one embodiment of the present invention can be applied to the display panel 6511. Therefore, an extremely lightweight electronic device can be realized. Furthermore, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be mounted thereon while keeping the thickness of the electronic device small. Furthermore, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0511] 20C shows an example of a television set. A television set 7100 includes a display portion 7000 built in a housing 7171. Here, the housing 7171 is supported by a stand 7173.

[0512] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can be highly reliable.

[0513] The television set 7100 shown in FIG. 20C can be operated using an operation switch provided on a housing 7171 and a separate remote control 7151.

[0514] 20D shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214. A display portion 7000 is incorporated in the housing 7211.

[0515] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can be highly reliable.

[0516] 20(E) and 20(F) show an example of digital signage.

[0517] 20E includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0518] 20F shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0519] 20E and 20F, the display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can have high reliability.

[0520] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it will attract people's attention, which can increase the advertising effectiveness of, for example, advertisements.

[0521] Furthermore, as shown in Figures 20(E) and 20(F), it is preferable that the digital signage 7300 or the digital signage 7400 be able to wirelessly communicate with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user.

[0522] The electronic devices shown in Figures 21(A) to 21(G) have a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function to measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0523] 21(A) to 21(G) have various functions, such as a function 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, time, etc., 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.

[0524] The electronic devices shown in FIGS. 21A to 21G will be described in detail below.

[0525] FIG. 21A is a perspective view showing a mobile information terminal 9171. The mobile information terminal 9171 can be used as, for example, a smartphone. The mobile information terminal 9171 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, or the like. The mobile information terminal 9171 can display text and image information on multiple surfaces thereof. FIG. 21A shows an example in which three icons 9050 are displayed. Information 9051 indicated by a dashed rectangle can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of the email or SNS message, the sender's name, the date and time, the remaining battery level, and radio wave intensity. Alternatively, the icon 9050 or the like may be displayed in the position where the information 9051 is displayed.

[0526] 21B is a perspective view of a mobile information terminal 9172. The mobile information terminal 9172 has a function of displaying information on three or more surfaces of the display portion 9001. Here, an example is shown in which information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9172 while the mobile information terminal 9172 is placed in a breast pocket of clothes.

[0527] 21C is a perspective view of a tablet terminal 9173. The tablet terminal 9173 is capable of executing various applications such as mobile phone calls, e-mails, document browsing and creation, music playback, internet communication, and computer games. The tablet terminal 9173 has a display portion 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front side of a housing 9000, operation keys 9005 as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0528] 21D is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display portion 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and reception with another information terminal and charge itself through a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0529] 21(E) to 21(G) are perspective views showing a foldable mobile information terminal 9201. FIG. 21(E) shows the mobile information terminal 9201 in an unfolded state, FIG. 21(G) shows it in a folded state, and FIG. 21(F) is a perspective view showing a state in the process of changing from one of FIG. 21(E) and FIG. 21(G) to the other. The mobile information terminal 9201 is highly portable when folded, and has a seamless, wide display area when unfolded, providing excellent viewability of the display. A display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by hinges 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm to 150 mm.

[0530] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when multiple configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate. [Example]

[0531] This example will describe in detail a manufacturing method and characteristics of a light-emitting device 1, which is a light-emitting device according to one embodiment of the present invention, and a comparative light-emitting device 1. The structural formulae of main compounds used in the light-emitting device 1 and the comparative light-emitting device 1 are shown below.

[0532] [ka]

[0533] (Method for fabricating light-emitting device 1) First, a silver (Ag) film was formed on a glass substrate by sputtering from the substrate side to a thickness of 100 nm as a reflective electrode, and then indium tin oxide containing silicon oxide (ITSO) was sequentially laminated by sputtering to a thickness of 10 nm as a transparent electrode, thereby forming a 2 mm x 2 mm first electrode 101. The transparent electrode functions as an anode, and is considered to be the first electrode 101 together with the reflective electrode.

[0534] Next, as a pretreatment for forming a light-emitting device on the substrate, the surface of the substrate was washed with water and baked at 200°C for 1 hour.

[0535] Then, about 10 -4 The substrate was introduced into a vacuum deposition apparatus whose internal pressure had been reduced to 100 Pa, and vacuum baking was carried out at 170° C. for 60 minutes in a heating chamber within the vacuum deposition apparatus, after which the substrate was allowed to cool for approximately 30 minutes.

[0536] Next, the substrate was fixed to a holder installed in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed faced downward, and a hole injection layer 111 was formed on the first electrode 101 by co-depositing N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and an electron acceptor material (OCHD-003) containing fluorine and having a molecular weight of 672 by a deposition method at a weight ratio of 1:0.03 (= PCBBiF:OCHD-003) and a film thickness of 10 nm.

[0537] On the hole injection layer 111, PCBBiF was deposited to a thickness of 102 nm to form a first hole transport layer, and then N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), represented by the above structural formula (ii), was deposited to a thickness of 10 nm to form a second hole transport layer, thereby forming the hole transport layer 112.

[0538] Subsequently, on the hole transport layer 112, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (iii) and N,N'-diphenyl-N,N'-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (iv) were co-deposited at a weight ratio of 1:0.015 (=αN-βNPAnth:3,10PCA2Nbf(IV)-02) to a film thickness of 25 nm, to form the light-emitting layer 113.

[0539] After this, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (v) was evaporated to a thickness of 15 nm, and then 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) represented by the above structural formula (vi) was evaporated to a thickness of 10 nm to form an electron transport layer 114.

[0540] Next, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form an electron injection layer 115, and then silver (Ag) and magnesium (Mg) were co-evaporated in a volume ratio of 1:0.1 to a thickness of 15 nm to form a second electrode 102.

[0541] After that, a cap layer was formed on the second electrode 102 by vapor-depositing 10.2 nm of N-(biphenyl-2-yl)-N-(3,3'',5',5''-tetra-tert-butyl-[1,1':3',1''-terphenyl]-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-02) represented by the above structural formula (vii), followed by 53.4 nm of 3-[4-([2,2'-binaphthalen]-6-yl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCP(βN2)) represented by the above structural formula (viii).

[0542] Next, in a glove box with a nitrogen atmosphere, the light-emitting device was sealed with a glass substrate to prevent it from being exposed to the atmosphere (a UV-curable sealant was applied around the element, UV was irradiated only onto the sealant without irradiating the light-emitting device, and heat treatment was performed at 80°C under atmospheric pressure for 1 hour), thereby forming light-emitting device 1.

[0543] (Method for producing comparative light-emitting device 1) Comparative light-emitting device 1 was fabricated in the same manner as light-emitting device 1, except that the hole transport layer in light-emitting device 1 was formed to a thickness of 100 nm and the capping layer was formed by vapor deposition of PCP(βN2) to a thickness of 62.8 nm. The thickness of the hole transport layer was selected so that the chromaticity of light-emitting device 1 and comparative light-emitting device 1 would be as close as possible.

[0544] Figure 22 shows the results of measuring the ordinary refractive index (n, Ordinary) and extraordinary refractive index (n, Extra-Ordinary) of mmtBumTPoFBi-02 and PCP(βN2) used in Light-emitting Device 1 and Comparative Light-emitting Device 1 fabricated in this example. The measurements were performed using a spectroscopic ellipsometer (M-2000U manufactured by J.A. Woollam Japan). The measurement sample used was a film of approximately 50 nm thickness formed by vacuum deposition of the materials for each layer on a quartz substrate.

[0545] 22 reveals that mmtBumTPoFBi-02, which constitutes the first layer 188 of the light-emitting device 1 and the comparative light-emitting device 1, is a low-refractive index material with an ordinary refractive index of 1.8 or less at 450 nm, and PCP(βN2), which constitutes the second layer 189, is a high-refractive index material with an ordinary refractive index of 1.9 or more at 450 nm. It was also found that the difference between these two materials is 0.1 or more. The mmtBumTPoFBi-02 is a monoamine compound containing an alkyl group. The PCP(βN2) is an organic compound containing a carbazole skeleton.

[0546] The device structures of Light-Emitting Device 1 and Comparative Light-Emitting Device 1 are shown in the table below.

[0547] [Table 1]

[0548] [Table 2]

[0549] The luminance-current density characteristics of light-emitting device 1 and comparative light-emitting device 1 are shown in Figure 23, their current efficiency-luminance characteristics in Figure 24, their luminance-voltage characteristics in Figure 25, their current density-voltage characteristics in Figure 26, their blue index-current density characteristics in Figure 27, and their electroluminescence spectra in Figure 28.

[0550] The values ​​of voltage, current, current density, CIE chromaticity, current efficiency, and blue index at an applied voltage of 4.40 V are shown below. The luminance, CIE chromaticity, and electroluminescence spectrum were measured using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) at room temperature.

[0551] The blue index (BI) is a value obtained by dividing the current efficiency (cd / A) by the y chromaticity calculated using the CIE 1931 color system. It is an index used to express the luminous properties of blue light. The smaller the y chromaticity, the higher the color purity of blue light. Blue light with high color purity can display the desired color even with a small luminance component. Furthermore, using blue light with high color purity reduces the required blue luminance in a display, thereby reducing power consumption. Therefore, the BI, which takes into account the y chromaticity, an index of blue purity, is sometimes used as a means of expressing the efficiency of blue light emission. The higher the BI, the better the efficiency of blue light emission in a display.

[0552] [Table 3]

[0553] 23 to 28 and Table 3 show that Light-Emitting Device 1 is a light-emitting element with good color purity. Furthermore, by using a capping layer formed by stacking materials with different refractive indices, it was found that the Light-Emitting Device 1 exhibits higher current efficiency and a higher blue index than Comparative Light-Emitting Device 1, which has a single capping layer, and thus has good characteristics.

[0554] Next, we will show the results of an investigation into the deterioration of light-emitting devices after storage at high temperature (85°C).

[0555] The samples had almost the same configuration as light-emitting device 1, from the substrate to the second electrode, except for the first hole transport layer, which was 100 nm thick. Then, a capping layer was formed on the second electrode by depositing mmtBumTPoFBi-02 to a thickness of 12.9 nm and PCP(βN2) to a thickness of 48.6 nm for sample 1, by depositing PCP(βN2) to a thickness of 61.7 nm and mmtBumTPoFBi-02 to a thickness of 1 nm for sample 2, and by depositing PCP(βN2) to a thickness of 61.3 nm for sample 3.

[0556] Samples 1 to 3 were stored at 85°C for 1000 hours, and the reflected bright-field images observed with an optical microscope using a 5x objective lens are shown in Fig. 29. As shown in Fig. 29, only Sample 3, whose capping layer was composed of an organic compound containing a single carbazole skeleton, exhibited irregular defects, while Samples 1 and 2, whose capping layers were composed of a monoamine compound containing an alkyl group and an organic compound containing a carbazole skeleton, did not exhibit irregular defects.

[0557] Next, the blue index-current density characteristics of Samples 1 to 3 are shown in Figures 30 to 32. Each series of graphs shows the characteristics for each time period during high-temperature storage. Tables 4 to 6 show the characteristics of Samples 1 to 3 when a voltage of 4.20 V is applied.

[0558] [Table 4]

[0559] [Table 5]

[0560] [Table 6]

[0561] 30 to 32 and Tables 4 to 6 show that the light-emitting device characteristics of Samples 1 and 2 do not change significantly even after high-temperature storage, while only Sample 3 shows a decrease in the blue index-current density characteristics the longer the high-temperature storage time. Table 6 shows that the decrease in blue index is caused by an increase in y chromaticity. This is due to the degradation of the cap layer caused by high-temperature storage, as shown in Figure 29.

[0562] Thus, it was found that the light-emitting device of one embodiment of the present invention, in which the capping layer is composed of a monoamine compound having an alkyl group and an organic compound having a carbazole skeleton, is a light-emitting device with good heat resistance and little deterioration due to storage at high temperatures.

[0563] In Sample 3, which had a single capping layer formed using an organic compound containing a carbazole skeleton, visual abnormalities were observed during the high-temperature storage test. On the other hand, in Samples 1 and 2, which also used an organic compound containing a carbazole skeleton for the capping layer but had a capping layer formed by laminating a layer of a monoamine compound containing an alkyl group, no visual abnormalities occurred. These results suggest that combining a layer of an organic compound containing a carbazole skeleton with a layer of a monoamine compound containing an alkyl group is effective in preventing visual abnormalities during the high-temperature storage test. It was revealed that this effect can be achieved by using these two materials simultaneously. It was particularly evident that the effect was greatest when a layer of an organic compound containing a carbazole skeleton was provided in contact with a layer of a monoamine compound containing an alkyl group.

[0564] Previous experiments have also revealed that when used as a capping layer for devices, particularly as the outermost layer, thin films of organic compounds containing a carbazole skeleton may undergo changes in film quality, such as crystallization, under high temperatures. However, when a thin film of an organic compound containing a carbazole skeleton is formed in contact with a thin film of a monoamine compound containing an alkyl group, these film quality abnormalities are suppressed. Therefore, thin films of monoamine compounds containing an alkyl group can be said to enhance the heat resistance of adjacent thin films, and this effect is particularly significant for thin films of organic compounds containing a carbazole skeleton. This effect was found to be achieved by forming a thin film of a monoamine compound containing an alkyl group as an underlayer on a thin film of an organic compound containing a carbazole skeleton. Furthermore, this effect was found to be achieved by forming a thin film of a monoamine compound containing an alkyl group as an upper layer on a thin film of an organic compound containing a carbazole skeleton, even with a thickness as thin as 1 nm. This effect is due to the combination of a thin film of an organic compound containing a carbazole skeleton and a thin film of a monoamine compound containing an alkyl group. [Explanation of symbols]

[0565] 100A display device 100B display device 100C display device 100D display device 100E display unit 100 display device 101 first electrode 101B first electrode 101G First electrode 101R First electrode 101W First electrode 102 second electrode 103B Organic compound layer 103Bf EL membrane 103G organic compound layer 103Gf EL membrane 103R Organic compound layer 103Rf EL membrane 103 Organic compound layer 104 Common layer 110B subpixel 110G subpixel 110R subpixel 110W subpixel 110 subpixels 111 Hole injection layer 112B Conductive layer 112R conductive layer 112 Hole transport layer 113 Light-emitting layer 114 Electron transport layer 115 Electron injection layer 116 Charge generation layer 117 P type layer 118 Electronic Relay Layer 119 Electron injection buffer layer 120 boards 122 Resin layer 125f inorganic insulating film 125 Inorganic insulating layer 126B Conductive layer 126R conductive layer 127a Insulating layer 127f insulating film 127 Insulating Layer 128 layers 129B Conductive layer 129R conductive layer 130B Light-emitting devices 130G Light Emitting Device 130R Light Emitting Device 130W Light Emitting Device 130 Light-emitting devices 131 Protective layer 132B Colored layer 132G colored layer 132R colored layer 140 Connection 141 areas 142 Adhesive layer 151B Conductive layer 151C conductive layer 151f Conductive film 151G conductive layer 151R conductive layer 151 Conductive layer 152B Conductive layer 152C conductive layer 152f Conductive film 152G Conductive layer 152R Conductive layer 152 Conductive layer 153 Insulating Layer 155 Cap Layer 156B Insulating layer 156C Insulation layer 156f insulating film 156G Insulation layer 156R Insulation layer 156 Insulating Layer 157 Light blocking layer 158B Sacrificial Layer 158Bf sacrificial film 158f Sacrificial film 158G Sacrificial Layer 158Gf sacrificial film 158R Sacrificial Layer 158Rf sacrificial film 159B Mask layer 159Bf Mask membrane 159G Mask layer 159Gf Mask Film 159R Mask layer 159Rf Mask Film 166 Conductive Layer 171 Insulating layer 172 Conductive layer 173 Insulating Layer 174 Insulating Layer 175 Insulating Layer 176 Plug 177 Pixel section 178 pixels 178a pixels 178b pixels 179 Conductive Layer 190B resist mask 190G resist mask 190R resist mask 191 Resist mask 201 Transistor 204 Connection 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 capacity 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 section 282 Circuit section 283a Pixel circuit 283 Pixel circuit section 284a pixels 284 pixel section 285 Terminal section 286 Wiring section 290 FPC 291 Circuit Board 292 PCB 301 Substrate 310 Transistor 311 Conductive layer 312 Low resistance region 313 Insulating Layer 314 Insulating Layer 315 Element isolation layer 317 Light blocking layer 351 Circuit Board 352 Circuit Board 353 FPC 354 IC 355 Wiring 356 circuits 501 first electrode 502 Second electrode 511 First Light Emitting Unit 512 Second Light Emitting Unit 513 Middle Class 600 Light-emitting devices 601 Source line driver circuit, driver circuit section 602 Pixel section 603 Gate line driving circuit 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 610 Element substrate 611 Switching FET 612 Current control FET 613 First electrode 614 Insulators 616 Organic compound layer 617 Second electrode 618 Light-emitting devices 623 FET 700A electronic equipment 700B Electronic equipment 721 Case 723 Mounting part 727 Earphones 750 earphones 751 Display Panel 753 Optical Components 756 Display area 757 frames 758 Nose pad 800A electronic equipment 800B Electronic equipment 820 Display section 821 Case 822 Communications Department 823 Mounting part 824 Control Unit 825 Imaging unit 827 Earphones 832 Lens 1000 insulating layers 6500 Electronic equipment 6501 Housing 6502 Display section 6503 Power button 6504 Button 6505 Speaker 6506 Microphone 6507 Camera 6508 Light source 6510 Protective materials 6511 Display Panel 6512 Optical components 6513 Touch Sensor Panel 6515 FPC 6516 IC 6517 Printed Circuit Board 6518 Battery 7000 Display 7100 Television equipment 7151 Remote Controlled Machine 7171 Case 7173 Stand 7200 Notebook Personal Computer 7211 Case 7212 keyboard 7213 Pointing Device 7214 External connection port 7300 Digital Signage 7301 Housing 7303 Speaker 7311 Information terminals 7400 Digital Signage 7401 Pillar 7411 Information terminals 9000 chassis 9001 Display section 9002 Camera 9003 Speaker 9005 Operation key 9006 Connection terminal 9007 Sensor 9008 Microphone 9050 Icon 9051 Information 9052 Information 9053 Information 9054 Information 9055 Hinge 9171 Mobile Information Terminal 9172 Mobile Information Terminal 9173 Tablet Devices 9200 Mobile Information Terminal 9201 Mobile Information Terminal

Claims

1. a first electrode; a second electrode; and a light-emitting layer located between the first electrode and the second electrode, and a cap layer; the second electrode is located between the light-emitting layer and the capping layer; the cap layer comprises at least a first material and a second material; the first substance and the second substance are substances whose refractive indices for ordinary light at any wavelength from 380 nm to 760 nm in the respective vapor-deposited films differ by 0.1 or more, the first substance is a monoamine compound containing an alkyl group, The second substance is an organic compound containing a carbazole skeleton.

2. a first electrode; a second electrode; and a light-emitting layer located between the first electrode and the second electrode, and a cap layer; the second electrode is located between the light-emitting layer and the capping layer; the cap layer has at least a first layer including a first material and a second layer including a second material; the first substance and the second substance are substances whose refractive indices for ordinary light at any wavelength from 380 nm to 760 nm in the respective vapor-deposited films differ by 0.1 or more, the first substance is a monoamine compound containing an alkyl group, The second substance is an organic compound containing a carbazole skeleton.

3. a first electrode; a second electrode; and a light-emitting layer located between the first electrode and the second electrode, and a cap layer; the second electrode is located between the light-emitting layer and the capping layer; the cap layer has at least a first layer including a second material and a second layer including the first material; the first layer is located between the second electrode and the second layer; the first substance and the second substance are substances whose refractive indices for ordinary light at any wavelength from 380 nm to 760 nm in the respective vapor-deposited films differ by 0.1 or more, the first substance is a monoamine compound containing an alkyl group, The second substance is an organic compound containing a carbazole skeleton.

4. a first electrode; a second electrode; and a light-emitting layer located between the first electrode and the second electrode, and a cap layer; the second electrode is located between the light-emitting layer and the capping layer; the cap layer has at least a first layer including a first material and a second layer including a second material; the first layer is in contact with the second electrode; the first substance and the second substance are substances whose refractive indices for ordinary light at any wavelength from 380 nm to 760 nm in the respective vapor-deposited films differ by 0.1 or more, the first substance is a monoamine compound containing an alkyl group, The second substance is an organic compound containing a carbazole skeleton.

5. In any one of claims 1 to 4, The first substance and the second substance are substances whose refractive indices for ordinary light at any wavelength from 380 nm to 760 nm in the evaporated films thereof differ by 0.3 or more.

6. In any one of claims 1 to 4, A light-emitting device in which the monoamine compound does not have a trifluoromethyl group.

7. In any one of claims 1 to 4, The monoamine compound is represented by the following general formula (G Ｌ A light-emitting device that is an organic compound represented by the formula (1). 【Chemistry 1】 (wherein the general formula (G Ｌ In the organic compound represented by 1), Ar １ ~Ar ３ 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 ４ ~Ar ６ Each of n, m, and l independently represents any one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and each of n, m, and l independently represents any one of integers of 0 to 3. Note that when any one or more of n, m, and l is 2 or more, a plurality of Ar １ , multiple Ar ２ , multiple Ar ３ may be the same or different. Ｌ 1) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms. Ｌ All hydrogen atoms in the organic compound represented by formula 1) may be independently deuterium atoms.

8. In any one of claims 1 to 4, The organic compound containing a carbazole skeleton is represented by the following general formula (G Ｈ A light-emitting device that is an organic compound represented by the formula (1). 【Chemistry 2】 (However, the general formula (G Ｈ In the organic compound represented by 1), R １１ ~R １８ each independently represents hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms; R １９ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms. All hydrogen atoms may be replaced by deuterium, and the aromatic hydrocarbon group and heteroaromatic group may have a structure in which multiple rings are bonded to each other, and when the group is composed of multiple rings, there may be multiple aromatic hydrocarbon groups, multiple heteroaromatic groups, or both an aromatic hydrocarbon group and a heteroaromatic group.

9. In any one of claims 1 to 4, The monoamine compound is represented by the following general formula (G Ｌ 1), an organic compound represented by The organic compound containing a carbazole skeleton is represented by the following general formula (G Ｈ A light-emitting device that is an organic compound represented by the formula (1). 【Transformation 3】 (General formula (G Ｌ In the organic compound represented by 1), Ar １ ~Ar ３ 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 ４ ~Ar ６ Each of n, m, and l independently represents any one of a substituted or unsubstituted aryl group having 6 to 30 carbon atoms and a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, and each of n, m, and l independently represents any one of integers of 0 to 3. Note that when any one or more of n, m, and l is 2 or more, a plurality of Ar １ , multiple Ar ２ , multiple Ar ３ may be the same or different. Ｌ The organic compound represented by the general formula (G 1) has one or more alkyl groups, and the alkyl groups are either linear or branched alkyl groups having 1 to 10 carbon atoms or cycloalkyl groups having 3 to 10 carbon atoms. Ｌ All hydrogen atoms in the organic compound represented by formula 1) may be independently deuterium atoms. In addition, the general formula (G Ｈ In the organic compound represented by 1), R １１ ~R １８ each independently represents hydrogen (including deuterium), a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms; R １９ represents a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaromatic group having 1 to 30 carbon atoms. All hydrogen atoms may be replaced by deuterium, and the aromatic hydrocarbon group and heteroaromatic group may have a structure in which multiple rings are bonded to each other, and when the group is composed of multiple rings, there may be multiple aromatic hydrocarbon groups, multiple heteroaromatic groups, or both an aromatic hydrocarbon group and a heteroaromatic group.

10. In claim 9, the refractive index of ordinary light at 450 nm in a vapor-deposited film of the first substance is 1.70 or less; A light-emitting device in which the refractive index of ordinary light at 450 nm in the vapor-deposited film of the second material is 1.80 or more.

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