Light-emitting device, electronic device, light-emitting apparatus, and lighting apparatus

Abstract

Provided is a light-emitting device with high light emission efficiency. Provided is an electronic device comprising a positive electrode, a negative electrode, and an EL layer positioned between the positive electrode and the negative electrode. The EL layer includes a first layer, a second layer, and a third layer. The first layer is positioned between the positive electrode and the second layer. The third layer is positioned between the second layer and the negative electrode. The first layer contains an organic compound having a hole transporting property. The third layer contains an organic compound having an electron transporting property. The organic compound having a hole transporting property and the organic compound having an electron transporting property have specific structures, and the organic compound having a hole transporting property and the organic compound having an electron transporting property each have the ordinary light refractive index of 1.5-1.75 for light with a wavelength of 455-465 nm.

Description

Technical Field

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

Background Art

[0002] The practical application of light-emitting devices (organic EL devices) that utilize electroluminescence (EL) using organic compounds has been progressing. The basic configuration of these light-emitting devices is such that an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying a voltage to this device to inject carriers and utilizing the recombination energy of the carriers, light emission from the light-emitting material can be obtained.

[0003] Since such a light-emitting device is self-luminous, when used as a pixel of a display, it has advantages such as higher visibility and no need for a backlight compared to liquid crystals, and is particularly suitable for flat panel displays. In addition, a display using such a light-emitting device can be manufactured to be thin and lightweight, which is also a great advantage. Furthermore, it is also characterized by a very fast response speed.

[0004] In addition, since these light-emitting devices can form a light-emitting layer continuously in two dimensions, planar light emission can be obtained. This is a characteristic that is difficult to achieve with point light sources typified by incandescent bulbs and LEDs, or line light sources typified by fluorescent lamps. Therefore, it has high utility value as a planar light source that can be applied to lighting and the like.

[0005] As described above, displays and lighting devices using light-emitting devices are suitable for various electronic devices, and research and development are underway to obtain light-emitting devices with better characteristics.

[0006] One of the problems often cited when organic EL devices are discussed is the low light extraction efficiency. In order to improve this, a configuration has been proposed in which a layer made of a low refractive index material is formed inside the EL layer (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] One aspect of the present invention aims to provide a light-emitting device with high luminous efficiency. Alternatively, one aspect of the present invention aims to provide any one of a light-emitting device, a light-emitting apparatus, an electronic device, a display device, or an electronic device with low power consumption.

[0009] The present invention only needs to solve any one of the above-mentioned problems.

Means for Solving the Problems

[0010] One aspect of the present invention has an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer has a first layer, a second layer, and a third layer. The first layer is positioned between the anode and the second layer, and the third layer is positioned between the second layer and the cathode. The first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties in light with a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less. This is an electronic device.

[0011] Alternatively, another aspect of the present invention has an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer has a first layer, a second layer, and a third layer. The first layer is positioned between the anode and the second layer, and the third layer is positioned between the second layer and the cathode. The first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having electron-transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and hydrocarbon groups forming bonds with a plurality of sp3 hybrid orbitals. The total number of carbon atoms forming bonds with sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron-transporting properties. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties in light with a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less. This is an electronic device.

[0012] Alternatively, another aspect of the present invention is an electronic device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer. The first layer is positioned between the anode and the second layer, and the third layer is positioned between the second layer and the cathode. The first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded with sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less. The organic compound having electron-transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds with a plurality of sp3 hybrid orbitals, and the total number of carbon atoms forming bonds with sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron-transporting properties. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties at light with a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less.

[0013] Alternatively, another aspect of the present invention is an electronic device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer. The first layer is positioned between the anode and the second layer, and the third layer is positioned between the second layer and the cathode. The first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded with sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light with a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0014] Alternatively, another aspect of the present invention has an anode, a cathode, and an EL layer positioned between the anode and the cathode, the EL layer having a first layer, a second layer, and a third layer, the first layer being positioned between the anode and the second layer, the third layer being positioned between the second layer and the cathode, the first layer containing an organic compound having hole-transporting properties, the third layer containing an organic compound having electron-transporting properties, the organic compound having electron-transporting properties having at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds with a plurality of sp3 hybrid orbitals, the total number of carbons forming bonds with the sp3 hybrid orbitals being 10% or more and 60% or less of the total number of carbons in the molecule of the organic compound having electron-transporting properties, and an electron device in which the ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0015] Alternatively, another aspect of the present invention is an electronic device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer, the first layer is positioned between the anode and the second layer, the third layer is positioned between the second layer and the cathode, the first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded with sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less. The organic compound having electron-transporting properties has at least one six-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds with a plurality of sp3 hybrid orbitals, and the total number of carbon atoms forming bonds with sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron-transporting properties. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0016] Alternatively, another aspect of the present invention is an electronic device in the above configuration, wherein the first layer is a hole-transporting layer and / or a hole-injecting layer.

[0017] Alternatively, another aspect of the present invention is an electronic device in the above configuration, wherein the third layer is an electron-transporting layer and / or an electron-injecting layer.

[0018] Alternatively, another aspect of the present invention is an electronic device in the above configuration, wherein one or both of the anode and the cathode have a function of reflecting all or part of the light emitted from the electronic device or the light incident on the electronic device.

[0019] Alternatively, another aspect of the present invention is an electronic device in the above configuration, wherein one or both of the anode and the cathode contain a metal.

[0020] Alternatively, in another aspect of the present invention, in the above configuration, the second layer is an electronic device that emits light.

[0021] One aspect of the present invention has an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer has a first layer, a second layer, and a third layer. The first layer is positioned between the anode and the second layer, and the third layer is positioned between the second layer and the cathode. The first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties in light with a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less. It is a light-emitting device.

[0022] Alternatively, in another aspect of the present invention, there is an anode, a cathode, and an EL layer positioned between the anode and the cathode. The EL layer has a first layer, a second layer, and a third layer. The first layer is positioned between the anode and the second layer, and the third layer is positioned between the second layer and the cathode. The first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties. The organic compound having electron-transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and hydrocarbon groups forming bonds with a plurality of sp3 hybrid orbitals. The total number of carbon atoms forming bonds with sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron-transporting properties. The ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties in light with a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less. It is a light-emitting device.

[0023] Alternatively, another aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer, the first layer is positioned between the anode and the second layer, the third layer is positioned between the second layer and the cathode, the first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less; the organic compound having electron-transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds with a plurality of sp3 hybrid orbitals, and the total number of carbon atoms forming bonds with the sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron-transporting properties; and the ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light having a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less.

[0024] Alternatively, another aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer, the first layer is positioned between the anode and the second layer, the third layer is positioned between the second layer and the cathode, the first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less; and the ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0025] Alternatively, another aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer, the first layer is positioned between the anode and the second layer, the third layer is positioned between the second layer and the cathode, the first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having electron-transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming a bond with a plurality of sp3 hybrid orbitals, and the total number of carbons forming a bond with the sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbons in the molecule of the organic compound having electron-transporting properties, and the ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0026] Alternatively, another aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has a first layer, a second layer, and a third layer, the first layer is positioned between the anode and the second layer, the third layer is positioned between the second layer and the cathode, the first layer contains an organic compound having hole-transporting properties, the third layer contains an organic compound having electron-transporting properties, the organic compound having hole-transporting properties is a monoamine compound, and the ratio of carbon atoms bonded with sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less; the organic compound having electron-transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds with a plurality of sp3 hybrid orbitals, and the total number of carbon atoms forming bonds with sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron-transporting properties; and the ordinary light refractive index of each of the organic compound having hole-transporting properties and the organic compound having electron-transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

[0027] Alternatively, another aspect of the present invention is a light-emitting device, in the above configuration, wherein the first layer is a hole-transporting layer and / or a hole-injecting layer.

[0028] Alternatively, another aspect of the present invention is a light-emitting device, in the above configuration, wherein the third layer is an electron-transporting layer and / or an electron-injecting layer.

[0029] Alternatively, another aspect of the present invention is a light-emitting device, in the above configuration, wherein one or both of the anode and the cathode have a function of reflecting all or part of the light emitted from the light-emitting device.

[0030] Alternatively, another aspect of the present invention is a light-emitting device, in the above configuration, wherein one or both of the anode and the cathode contain a metal.

[0031] Alternatively, in another aspect of the present invention, in the above configuration, the second layer is a light-emitting device that emits light.

[0032] Alternatively, in another aspect of the present invention, an electronic device having the above electronic device or light-emitting device and at least one of a sensor, an operation button, a speaker, and a microphone.

[0033] Alternatively, in another aspect of the present invention, a light-emitting device having the above electronic device or light-emitting device and at least one of a transistor and a substrate.

[0034] Alternatively, in another aspect of the present invention, a lighting device having the above electronic device or light-emitting device and a housing.

[0035] Note that the light-emitting device in this specification includes an image display device using a light-emitting device. In addition, a module in which a connector, for example, an anisotropic conductive film or a TCP (Tape Carrier Package), is attached to the light-emitting device, a module in which a printed wiring board is provided at the tip of the TCP, or a module in which an IC (integrated circuit) is directly mounted on the light-emitting device by a COG (Chip On Glass) method may also be included in the light-emitting device. Furthermore, lighting fixtures and the like may have a light-emitting device.

Advantages of the Invention

[0036] In one aspect of the present invention, a light-emitting device with high luminous efficiency can be provided. Alternatively, in one aspect of the present invention, a light-emitting device, a light-emitting device, an electronic device, a display device, or an electronic device with low power consumption can be provided.

[0037] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that other effects will be naturally apparent from the description in the specification, drawings, claims, etc., and it is possible to extract these other effects from the description in the specification, drawings, claims, etc.

Brief Description of the Drawings

[0038] Figures 1A, 1B, 1C, and 1D are schematic diagrams of a light-emitting device. Figures 2A and 2B are diagrams showing an active matrix light-emitting device. Figures 3A and 3B are diagrams showing an active matrix light-emitting device. Figure 4 is a diagram showing an active matrix light-emitting device. Figures 5A and 5B are diagrams showing a passive matrix light-emitting device. Figures 6A and 6B are diagrams showing a lighting device. Figures 7A, 7B1, 7B2, and 7C are diagrams showing an electronic device. Figures 8A, 8B, and 8C are diagrams showing an electronic device. Figure 9 is a diagram showing a lighting device. Figure 10 is a diagram showing a lighting device. Figure 11 is a diagram showing an in-vehicle display device and a lighting device. Figures 12A and 12B are diagrams showing an electronic device. Figures 13A, 13B, and 13C are diagrams showing an electronic device. Figure 14 shows the luminance-current density characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3. Figure 15 shows the luminance-voltage characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3. Figure 16 shows the current efficiency-luminance characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3. Figure 17 shows the current density-voltage characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3. Figure 18 shows the blue index (BI)-luminance characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3. Figure 19 shows the emission spectra of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3. Figure 20 shows the data obtained by measuring the refractive indices of mmtBumTPoFBi-02 and PCBBiF. Figure 21 shows the data obtained by measuring the refractive indices of mmtBumBPTzn, mPn-mDMePyPTzn, Li-6mq, and Liq. Figure 22 shows the data obtained by measuring the refractive index of mmtBumTPoFBi-02. Figure 23 shows the data obtained by measuring the refractive index of mmtBumBPTzn. Figure 24 shows the data obtained by measuring the refractive index of Li-6mq. Figure 25 is a diagram showing the luminance-current density characteristics of Comparative Light-Emitting Device 10, Comparative Light-Emitting Device 11, Comparative Light-Emitting Device 12, and Light-Emitting Device 10. Figure 26 is a diagram showing the current efficiency-luminance characteristics of Comparative Light-Emitting Device 10, Comparative Light-Emitting Device 11, Comparative Light-Emitting Device 12, and Light-Emitting Device 10. Figure 27 is a diagram showing the luminance-voltage characteristics of Comparative Light-Emitting Device 10, Comparative Light-Emitting Device 11, Comparative Light-Emitting Device 12, and Light-Emitting Device 10. Figure 28 is a diagram showing the current-voltage characteristics of Comparative Light-Emitting Device 10, Comparative Light-Emitting Device 11, Comparative Light-Emitting Device 12, and Light-Emitting Device 10. Figure 29 is a diagram showing the blue index-luminance characteristics of Comparative Light-Emitting Device 10, Comparative Light-Emitting Device 11, Comparative Light-Emitting Device 12, and Light-Emitting Device 10. Figure 30 is a diagram showing the emission spectra of Comparative Light-Emitting Device 10, Comparative Light-Emitting Device 11, Comparative Light-Emitting Device 12, and Light-Emitting Device 10. Figure 31 shows the data obtained by measuring the refractive indices of dchPAF and PCBBiF.

Embodiments for Carrying Out the Invention

[0039] 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 those skilled in the art can easily understand that the form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments shown below.

[0040] (Embodiment 1)

[0041] FIG. 1A shows a diagram representing a light-emitting device according to an aspect of the present invention. FIG. 1 shows an anode 101, a cathode 102, and an EL layer 103, and the EL layer 103 has a structure including 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 light-emitting layer 113 is a layer having at least a light-emitting material. Note that the configuration of the EL layer 103 is not limited to this, and an aspect in which some of the above-described layers are not formed, or an aspect in which other functional layers such as a carrier blocking layer, an exciton blocking layer, and an intermediate layer are formed may be used.

[0042] In one aspect of the present invention, a low-refractive-index layer is provided in both a region (hole transport region 120) between the light-emitting layer 113 and the anode 101 and a region (electron transport region 121) between the light-emitting layer 113 and the cathode 102 in the EL layer 103.

[0043] The low-refractive-index layer is a layer-like region substantially parallel to the anode 101 or the cathode 102, and is a region having a refractive index lower than that of at least the light-emitting layer 113. Usually, since the refractive index of an organic compound constituting a light-emitting device is about 1.8 to 1.9, the refractive index of the low-refractive-index layer is 1.75 or less. Specifically, the ordinary light refractive index in the blue light-emitting region (455 nm or more and 465 nm or less) is 1.50 or more and 1.75 or less, or the ordinary light refractive index in light of 633 nm usually used for measuring the refractive index is preferably 1.45 or more and 1.70 or less.

[0044] When light is incident on a material having optical anisotropy, the light having a vibration plane parallel to the optical axis is called extraordinary light (ray), and the light having a vibration plane perpendicular to the optical axis is called ordinary light (ray). However, the refractive index with respect to ordinary light and the refractive index with respect to extraordinary light of the material may be different. In such a case, by performing anisotropy analysis, the ordinary light refractive index and the extraordinary light refractive index can be separated and each refractive index can be calculated. In this specification, when both the ordinary light refractive index and the extraordinary light refractive index exist in the measured material, the ordinary light refractive index is used as an index.

[0045] Further, not all of the hole transport region 120 and the electron transport region 121 need to be low refractive index layers, and at least a part thereof in the thickness direction of each of the hole transport region 120 and the electron transport region 121 may be provided as a low refractive index layer. For example, in the hole transport region 120, at least one of the functional layers provided in the hole transport region 120, such as the hole injection layer 111, the hole transport layer 112, and the electron blocking layer, may be a low refractive index layer. In the electron transport region 121, at least one of the functional layers provided in the electron transport region 121, such as the hole blocking layer, the electron transport layer 114, and the electron injection layer 115, may be a low refractive index layer.

[0046] The low refractive index layer can be formed by forming each functional layer using a substance having a relatively small refractive index. However, usually, high carrier transportability and low refractive index are in a trade-off relationship. This is because the carrier transportability in organic compounds largely originates from the presence of unsaturated bonds, and organic compounds having many unsaturated bonds tend to have a high refractive index. Even if a material has a low refractive index, if its carrier transportability is low, problems such as an increase in driving voltage, a decrease in luminous efficiency and reliability due to the breakdown of carrier balance will occur, and a light-emitting device having good characteristics cannot be obtained. Also, even if a material has sufficient carrier transportability and a low refractive index, if it has an unstable structure, problems with the glass transition point (Tg) and durability will make it impossible to obtain a light-emitting device with good reliability.

[0047] Therefore, as an organic compound having hole transportability that can be used in the hole transport region 120, it is preferable to use a monoamine compound having a first aromatic group, a second aromatic group, and a third aromatic group, and the first aromatic group, the second aromatic group, and the third aromatic group are bonded to the same nitrogen atom.

[0048] The monoamine compound preferably has a ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the molecule of 23% or more and 55% or less, and 1It is preferable that the compound has an integral value of signals below 4 ppm exceeding the integral value of signals at 4 ppm or higher in the result of measuring the monoamine compound by 1H-NMR.

[0049] Further, the monoamine compound preferably has at least one fluorene skeleton, and any one or more of the first aromatic group, the second aromatic group, and the third aromatic group are fluorene skeletons.

[0050] Examples of the organic compound having the above hole transporting property include organic compounds having a structure such as the following general formula (G h1 1) to (G h1 4).

[0051]

Chemical formula

[0052] In the above general formula (G h1 1), Ar 1 , Ar 2 each independently represents a benzene ring or a substituent in which two or three benzene rings are bonded to each other. However, one or both of Ar 1 , Ar 2 have one or more hydrocarbon groups having 1 to 12 carbon atoms in which carbon forms bonds only with sp3 hybrid orbitals, and the total number of carbon atoms contained in all the hydrocarbon groups bonded to Ar 1 and Ar 2 is 8 or more, and the total number of carbon atoms contained in all the hydrocarbon groups bonded to either Ar 1 or Ar 2 is 6 or more. When a plurality of linear alkyl groups having 1 to 2 carbon atoms are bonded to Ar 1 or Ar 2 as the hydrocarbon group, the linear alkyl groups may be bonded to each other to form a ring.

[0053]

Chemical formula

[0054] In the above general formula (G h1 2), m and r each independently represent 1 or 2, and m + r is 2 or 3. Also, t each independently represents an integer from 0 to 4, and is preferably 0. Also, R 5 represents either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. When m is 2, the types, numbers, and positions of the substituents of the two phenylene groups may be the same or different. When r is 2, the types, numbers, and positions of the substituents of the two phenyl groups may be the same or different. Also, when t is an integer from 2 to 4, the plurality of R 5 may be the same or different from each other, and R 5 may be such that adjacent groups are bonded to each other to form a ring.

[0055]

Chemical formula

[0056] In the above general formula (G h1 2) and (G h1 3), n and p each independently represent 1 or 2, and n + p is 2 or 3. s each independently represents an integer from 0 to 4, and is preferably 0. Also, R 4 represents either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. When n is 2, the types, numbers, and positions of the substituents of the two phenylene groups may be the same or different. When p is 2, the types, numbers, and positions of the substituents of the two phenyl groups may be the same or different. Also, when s is an integer from 2 to 4, the plurality of R 4 may be the same or different from each other.

[0057]

Chemical formula

[0058] In the above general formula (G h1 2) to (G h1 4), R 10 to R 14 and R 20 to R 24 each independently represent hydrogen or a hydrocarbon group having 1 to 12 carbon atoms in which carbon forms bonds only with sp3 hybrid orbitals. Note that at least 3 of R 10 to R 14 , and at least 3 of R 20 to R 24 are preferably hydrogen. As the hydrocarbon group having 1 to 12 carbon atoms in which carbon forms bonds only with sp3 hybrid orbitals, a tert-butyl group and a cyclohexyl group are preferable. However, the total number of carbon atoms contained in R 10 to R 14 and R 20 to R 24 is 8 or more, and the total number of carbon atoms contained in either one of R 10 to R 14 or R 20 to R 24 is 6 or more. R 4 , R 10 to R 14 and R 20 to R 24 may be such that adjacent groups are bonded to each other to form a ring.

[0059] Also, in the above general formula (G h1 1) to (G h1 4), u represents an integer from 0 to 4, and 0 is preferable. When u is an integer from 2 to 4, the plurality of R 3 may be the same or different from each other. Also, R 1 , R 2 and R 3 each independently represent an alkyl group having 1 to 4 carbon atoms, and R 1 and R 2 may be bonded to each other to form a ring.

[0060] In addition, as one of the materials having hole transporting properties that can be used in the hole transport region 120, an arylamine compound having at least one aromatic group, the aromatic group having a first to third benzene ring and at least three alkyl groups, is also preferable. The first to third benzene rings are bonded in this order, and it is assumed that the first benzene ring is directly bonded to the nitrogen of the amine.

[0061] Further, the first benzene ring may further have a substituted or unsubstituted phenyl group, and preferably has an unsubstituted phenyl group. Further, the second benzene ring or the third benzene ring may have a phenyl group substituted with an alkyl group.

[0062] Among the first to third benzene rings, hydrogen is not directly bonded to the carbon at the 1-position and 3-position of two or more benzene rings, preferably all benzene rings, and is bonded to any one of the above-mentioned first to third benzene rings, the phenyl group substituted with the above-mentioned alkyl group, the above-mentioned at least three alkyl groups, and the nitrogen of the above-mentioned amine.

[0063] In addition, the arylamine compound preferably further has a second aromatic group. The second aromatic group is preferably a group having an unsubstituted monocyclic ring or a substituted or unsubstituted condensed ring of 3 rings or less, and among them, a substituted or unsubstituted condensed ring of 3 rings or less, and the condensed ring is more preferably a group having a condensed ring with 6 to 13 carbon atoms forming the ring, and further preferably a group having a fluorene ring. The dimethylfluorenyl group is preferable as the second aromatic group.

[0064] In addition, the arylamine compound preferably further has a third aromatic group. The third aromatic group is a group having 1 to 3 substituted or unsubstituted benzene rings.

[0065] The alkyl groups substituting at least three of the above-mentioned alkyl groups and phenyl groups are preferably chain alkyl groups having 2 to 5 carbon atoms. In particular, as the alkyl group, a chain alkyl group having a branch of 3 to 5 carbon atoms is preferable, and a t-butyl group is more preferable.

[0066] Examples of the material having the hole transporting property as described above include organic compounds having structures such as the following (G h2 1) to (G h2 3).

[0067]

Chemical formula

[0068] In the above general formula (G h2 1), Ar 101 represents a substituted or unsubstituted benzene ring, or a substituent in which two or three substituted or unsubstituted benzene rings are bonded to each other.

[0069]

Chemical formula

[0070] In the above general formula (G h2 2), x and y each independently represent 1 or 2, and x + y is 2 or 3. Further, R 109 represents an alkyl group having 1 to 4 carbon atoms, and w represents an integer of 0 to 4. Further, R 141 to R 145 each independently represent any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a cycloalkyl group having 5 to 12 carbon atoms. When w is 2 or more, the plurality of R 109 may be the same or different from each other. When x is 2, the types, numbers, and bonding positions of the substituents of the two phenylene groups may be the same or different. When y is 2, the types, numbers, and bonding positions of the substituents of the two R 141 to R 145The types and the number of substituents of the phenyl group having the same may be the same or different.

[0071]

Chemical formula

[0072] In addition, in the above general formula (G h2 3), R 101 to R 105 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 6 to 12 carbon atoms, and a substituted or unsubstituted phenyl group.

[0073] Also, in the above general formulas (G h2 1) to (G h2 3), R 106 , R 107 and R 108 each independently represents an alkyl group having 1 to 4 carbon atoms, and v represents an integer from 0 to 4. When v is 2 or more, a plurality of R 108 may be the same or different from each other. Also, one of R 111 to R 115 is a substituent represented by the above general formula (g1), and the rest each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted phenyl group. Further, in the above general formula (g1), one of R 121 to R 125 is a substituent represented by the above general formula (g2), and the rest each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms. Also, in the above general formula (g2), R 131 to R 135 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms. Note that R 111 to R 115 , R 121 to R 125 and R 131 to R 135Of these, at least 3 or more are alkyl groups having 1 to 6 carbon atoms, and R 111 to R 115 The number of substituted or unsubstituted phenyl groups is 1 or less, and R 121 to R 125 and R 131 to R 135 The number of phenyl groups substituted with an alkyl group having 1 to 6 carbon atoms is 1 or less. Also, in at least two of the three combinations of R 112 and R 114 , R 122 and R 124 , and R 132 and R 134 , at least one R is other than hydrogen.

[0074] The organic compound having hole transporting properties as described above has a normal light refractive index in the blue light emission region (455 nm or more and 465 nm or less) of 1.50 or more and 1.75 or less, or a normal light refractive index in the 633 nm light usually used for measuring the refractive index of 1.45 or more and 1.70 or less, and is an organic compound having good hole transporting properties. At the same time, it is also possible to obtain an organic compound having a high Tg and good reliability. Such an organic compound having hole transporting properties can be used as a material for the hole transport layer 112 because it also has sufficient hole transporting properties.

[0075] When the organic compound having hole transporting properties is used for the hole injection layer 111, it is preferable to mix and use a substance having an acceptor property with the organic compound having hole transporting properties. As the substance having an acceptor property, a compound having an electron-withdrawing group (halogen group or cyano group) can be used, and 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene) malononitrile, and the like can be mentioned. In particular, a compound in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms like HAT-CN is thermally stable and preferable. Further, a [3]radialene derivative having an electron-withdrawing group (particularly a halogen group such as a fluoro group or a cyano group) is preferable because of its very high electron-accepting property. Specifically, α,α’,α’’-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], and the like can be mentioned.

[0076] As substances having acceptor properties, in addition to the organic compounds described above, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, and the like can be used. In addition, phthalocyanine (abbreviation: H 2A hole injection layer 111 can also be formed of a phthalocyanine complex compound such as phthalocyanine (Pc) or copper phthalocyanine (CuPc), an aromatic amine compound such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS). A substance having acceptor properties can extract electrons from an adjacent hole transport layer (or hole transport material) by applying an electric field.

[0077] When the hole injection layer 111 is formed by mixing the above-mentioned material having acceptor properties with a material having hole transporting properties, a material for forming the electrode can be selected regardless of the work function. That is, not only a material with a large work function but also a material with a small work function can be used as the anode 101.

[0078] As an organic compound having electron transporting properties that can be used in the electron transport region 121, it preferably has at least one 6-membered heteroaromatic ring containing 1 to 3 nitrogens, has a plurality of aromatic hydrocarbon rings with 6 to 14 carbon atoms forming the ring, at least 2 of the plurality of aromatic hydrocarbon rings are benzene rings, and uses an organic compound having a plurality of hydrocarbon groups forming bonds with sp3 hybrid orbitals.

[0079] In addition, for such an organic compound, the ratio of the total carbon number forming bonds with sp3 hybrid orbitals to the total carbon number in the molecule of the organic compound is preferably 10% or more and 60% or less, and more preferably 10% or more and 50% or less. Or, for such an organic compound, 1 The integral value of the signal less than 4 ppm in the result of measuring the organic compound by 1H-NMR is preferably 1 / 2 times or more of the integral value of the signal of 4 ppm or more.

[0080] Note that the molecular weight of the organic compound having the above electron transporting property is preferably 500 or more and 2000 or less. Further, all hydrocarbon groups that form bonds with sp3 hybrid orbitals of the organic compound are preferably bonded to an aromatic hydrocarbon ring having 6 to 14 carbon atoms that forms the above ring, and the LUMO of the organic compound is not distributed in the aromatic hydrocarbon ring.

[0081] As the organic compound having the electron transporting property, an organic compound represented by the following general formula (G e1 1) or (G e1 2) is preferable.

[0082]

Chemical formula

[0083] In the formula, A represents a 6-membered heteroaromatic ring containing 1 to 3 nitrogen atoms, and any of a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, and a triazine ring is preferable.

[0084] Further, R 200 represents any of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituent represented by the formula (G1 e1 -1).

[0085] At least one of R 201 to R 215 is a phenyl group having a substituent, and the others each independently represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, and a substituted or unsubstituted pyridyl group. Note that R 201 , R 203 , R 205 , R 206 , R 208 , R 210 , R 211 , R 213 and R 215is preferably hydrogen. The phenyl group having the substituent has one or two substituents, and each of the substituents is independently an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring.

[0086] In addition, the organic compound represented by the above general formula (G e1 1) has a plurality of hydrocarbon groups selected from an alkyl group having 1 to 6 carbon atoms and an alicyclic group having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule is 10% or more and 60% or less.

[0087] Further, as the organic compound having the electron transporting property, an organic compound represented by the following general formula (G e1 2) is preferable.

[0088]

Chemical formula

[0089] In the formula, two or three of Q 1 to Q 3 represent N, and when two of the above Q 1 to Q 3 are N, the remaining one represents CH.

[0090] Also, at least one of R 201 to R 215 is a phenyl group having a substituent, and the others each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring, or a substituted or unsubstituted pyridyl group. Note that R 201 , R 203 , R 205 , R 206 , R 208 , R 210 , R 211 , R 213 and R 215is preferably hydrogen. The phenyl group having the substituent has one or two substituents, and each of the substituents is independently an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring.

[0091] In addition, the organic compound represented by the above general formula (G e1 2) has a plurality of hydrocarbon groups selected from an alkyl group having 1 to 6 carbon atoms and an alicyclic group having 3 to 10 carbon atoms, and the ratio of the total number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule is preferably 10% or more and 60% or less.

[0092] Further, in the organic compound represented by the above general formula (G e1 1) or (G e1 2), the phenyl group having a substituent is preferably a group represented by the following formula (G e1 1-2).

[0093]

Chemical formula

[0094] In the formula, α represents a substituted or unsubstituted phenylene group, and is preferably a meta-substituted phenylene group. When the meta-substituted phenylene group has one substituent, the substituent is also preferably substituted at the meta position. The substituent is preferably an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a t-butyl group.

[0095] R 220 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring.

[0096] Also, j and k represent 1 to 2. When j is 2, the plurality of αs may be the same or different from each other. When k is 2, the plurality of Rs 220 may be the same or different from each other. Note that R 220 is preferably a phenyl group, or a phenyl group having an alkyl group with 1 to 6 carbon atoms or an alicyclic group with 3 to 10 carbon atoms at one or both of the two meta-positions. It is more preferable that the substituent which the phenyl group has at one or both of the two meta-positions is an alkyl group with 1 to 6 carbon atoms, and it is even more preferable that it is a t-butyl group.

[0097] The organic compound having the electron transporting property as described above is an organic compound having a normal light refractive index in the blue light emission region (455 nm or more and 465 nm or less) of 1.50 or more and 1.75 or less, or a normal light refractive index in the light of 633 nm usually used for measuring the refractive index of 1.45 or more and 1.70 or less, and having good electron transporting property.

[0098] When the organic compound having the electron transporting property is used for the electron transport layer 114, it is preferable that the electron transport layer 114 further has a metal complex of an alkali metal or an alkaline earth metal. A heterocyclic compound having a diazine skeleton, a heterocyclic compound having a triazine skeleton, and a heterocyclic compound having a pyridine skeleton are preferable from the viewpoint of driving life because the energy when forming an excited complex with an organometallic complex of an alkali metal is likely to be stabilized (the emission wavelength of the excited complex is likely to be shifted to a longer wavelength). In particular, a heterocyclic compound having a diazine skeleton and a heterocyclic compound having a triazine skeleton are suitable for the energy stabilization of the excited complex because their LUMO levels are deep.

[0099] Incidentally, the organometallic complex of the above alkali metal is preferably a lithium organometallic complex. Alternatively, the organometallic complex of the above alkali metal preferably has a ligand having a quinolinol skeleton. More preferably, the organometallic complex of the above alkali metal is preferably a lithium complex containing an 8-quinolinolato structure or a derivative thereof. As a derivative of the lithium complex containing an 8-quinolinolato structure, a lithium complex containing an 8-quinolinolato structure having an alkyl group is preferable, and it is particularly preferable to have a methyl group.

[0100] When the lithium complex containing an 8-quinolinolato structure has an alkyl group, it is preferable that the alkyl group possessed by the complex is one. The 8-quinolinolato lithium having an alkyl group can be a metal complex with a small refractive index. Specifically, the ordinary light refractive index for light with a wavelength in the range of 455 nm or more and 465 nm or less in the thin film state can be 1.45 or more and 1.70 or less, and the ordinary light refractive index for light with a wavelength of 633 nm can be 1.40 or more and 1.65 or less.

[0101] In particular, by using 6-alkyl-8-quinolinolato lithium having an alkyl group at the 6-position, there is an effect of reducing the driving voltage of the light-emitting device. Among 6-alkyl-8-quinolinolato lithium, it is more preferable to use 6-methyl-8-quinolinolato lithium.

[0102] Here, the above 6-alkyl-8-quinolinolato lithium can be represented by the following general formula (G1).

[0103]

Chemical formula

[0104] However, in the above general formula (G1), R represents an alkyl group having 1 to 3 carbon atoms.

[0105] In the metal complex represented by the general formula (G1), a more preferred embodiment is the metal complex represented by the following structural formula (100).

[0106]

Chemical formula

[0107] As described above, the organic compound having electron transporting properties used in the electron transport layer 114 in the light-emitting device of one embodiment of the present invention preferably has an alkyl group having 3 or 4 carbon atoms. In particular, the organic compound having electron transporting properties preferably has a plurality of such alkyl groups. However, if the number of alkyl groups in the molecule is too large, the carrier transport property will decrease. Therefore, the ratio of carbon atoms forming bonds with sp3 hybrid orbitals in the organic compound having electron transporting properties is preferably 10% or more and 60% or less, more preferably 10% or more and 50% or less, based on the total number of carbon atoms in the organic compound. An organic compound having electron transporting properties with such a configuration can achieve a low refractive index without significantly impairing the electron transporting properties.

[0108] As described above, by having an organic compound having electron transporting properties with a small refractive index and a metal complex of an alkali metal with a small refractive index, a layer with a smaller refractive index can be obtained without causing a significant deterioration such as a driving voltage. As a result, the extraction efficiency of light emitted from the light-emitting layer 113 is improved, and the light-emitting device of one embodiment of the present invention can be a light-emitting element with good luminous efficiency.

[0109] Subsequently, examples of other structures and materials of the light-emitting device of one embodiment of the present invention will be described. The light-emitting device of one embodiment of the present invention has an EL layer 103 composed of a plurality of layers between a pair of electrodes, an anode 101 and a cathode 102, as described above. The EL layer 103 has a light-emitting layer 113 having a light-emitting material, a hole transport region 120, and an electron transport region 121. Note that the hole transport region 120 and the electron transport region 121 have low refractive index layers.

[0110] The anode 101 is preferably formed using a metal, alloy, conductive compound, or a mixture thereof having a large work function (specifically, 4.0 eV or more). Specifically, for example, indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO), etc. can be mentioned. These conductive metal oxide films are usually formed by a sputtering method, but may also be produced by applying a sol-gel method or the like. As an example of the production method, indium zinc oxide can be formed by a sputtering method using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. In addition, indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by a sputtering method using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. In addition to this, materials used for the anode 101 include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metal materials (for example, titanium nitride), etc. Alternatively, graphene can also be used as the material for the anode 101. Note that by using the composite material described later for the layer in contact with the anode 101 in the EL layer 103, the electrode material can be selected regardless of the work function.

[0111] In addition, when the anode 101 is formed of a material having permeability to visible light, a light-emitting device that emits light from the cathode side as shown in FIG. 1C can be obtained. When the anode 101 is formed on the substrate side, this light-emitting device can be a so-called bottom emission type light-emitting device.

[0112] The EL layer 103 preferably has a laminated structure, but the laminated structure is not particularly limited, and various functional layers such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, a carrier blocking layer (hole blocking layer, electron blocking layer), an exciton blocking layer, an intermediate layer, and a charge generation layer can be used. Note that any of the layers may not be provided. In the present embodiment, as shown in FIG. 1A, in addition to the light emitting layer 113, a configuration having a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115, and as shown in FIG. 1B, in addition to the electron transport layer 114, the light emitting layer 113, the hole injection layer 111, and the hole transport layer 112, two types of configurations having a charge generation layer 116 will be described. Note that at least one of each of the functional layers existing in the hole transport region 120 and the electron transport region 121 is a low refractive index layer, and the configuration has already been described. Hereinafter, materials that can form these functional layers when the functional layers are not low refractive index layers will be specifically shown.

[0113] The hole injection layer 111 is a layer containing a substance having an acceptor property. As the substance having an acceptor property, either an organic compound or an inorganic compound can be used.

[0114] As the substance having an acceptor property, a compound having an electron-withdrawing group (halogen group or cyano group) can be used, such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene) malononitrile, and the like. In particular, a compound in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms like HAT-CN is thermally stable and preferable. Further, a [3]radialene derivative having an electron-withdrawing group (particularly a halogen group such as a fluoro group or a cyano group) is preferable because of its very high electron-accepting property. Specifically, α,α’,α’’-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], and the like can be mentioned. As the acceptor substance, in addition to the organic compounds described above, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, and the like can be used. In addition, phthalocyanine-based complex compounds such as phthalocyanine (abbreviation: H 2 Pc) and copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4’-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N’-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N’-diphenyl-(1,1’-biphenyl)-4,4’-diamine (abbreviation: DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can also form the hole injection layer 111. The acceptor substance can extract electrons from the adjacent hole transport layer (or hole transport material) by applying an electric field.

[0115] In addition, as the hole injection layer 111, a composite material in which the acceptor substance is contained in a material having hole transport properties can also be used. By using a composite material in which the acceptor substance is contained in a material having hole transport properties, a material for forming an electrode can be selected regardless of the work function. That is, as the anode 101, not only a material with a large work function but also a material with a small work function can be used.

[0116] As the material having hole transport properties used in the composite material, various organic compounds such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that, as the material having hole transport properties used in the composite material, it is preferably a substance having a hole mobility of 1×10 -6 cm 2 / Vs or more. Hereinafter, organic compounds that can be used as the material having hole transport properties in the composite material will be specifically listed.

[0117] Examples of aromatic amine compounds that can be used in the composite material include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), and the like. Specific examples of the carbazole derivative include 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenylanthracen-9-yl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, and the like can be used.Examples of the aromatic hydrocarbon include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, and the like. In addition, pentacene, coronene, and the like can also be used. Further, it may have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like. The organic compound of one embodiment of the present invention can also be used.

[0118] In addition, high molecular compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N’-bis(4-butylphenyl)-N,N’-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used.

[0119] As the material having hole transporting property used in the composite material, it is more preferable that it has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine 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. In addition, when these second organic compounds are substances having an N,N-bis(4-biphenyl)amino group, it is preferable because a light-emitting device with good lifetime can be fabricated. Specific examples of the second organic compound 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-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-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: BBAαNβNB-03), 4,4'-Diphenyl-4''-(7-phenyl)naphthalen-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthalen-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthalen-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthalen-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-(5;2'-binaphthalen-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''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-diphenyl-4'-(2-naphthyl)-4''-{9-(4-biphenylyl)carbazole}triphenylamine (abbreviation: YGTBiβNB), 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(4-biphenylyl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(1,1'-biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,(9-Dimethyl-9H-fluoren-2-yl)-9,9'-spirobi(9H-fluorene)-4-amine (abbreviation: oFBiSF), N-(4-Biphenyl)-N-(dibenzofuran-4-yl)-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: FrBiF), N-[4-(1-Naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-Phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-Phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-Phenyl-4'-[4-(9-phenylfluorene-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-Diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-Naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(1,1'-Biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-Bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-4-amine, N,N-Bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-3-amine, N,N-Bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-2-amine, N,N-Bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-1-amine, etc. can be mentioned.,

[0120] In addition, the material having hole transporting property used in the composite material preferably has a relatively deep HOMO level of -5.7 eV or more and -5.4 eV or less. When the material having hole transporting property used in the composite material has a relatively deep HOMO level, injection of holes into the hole transport layer 112 becomes easy, and it becomes easy to obtain a light-emitting device with good lifetime. Further, since the material having hole transporting property used in the composite material is a substance having a relatively deep HOMO level, induction of holes is moderately suppressed, and a light-emitting device with better lifetime can be obtained.

[0121] In addition, by further mixing a fluoride of an alkali metal or an alkaline earth metal into the above composite material (preferably, the atomic ratio of fluorine atoms in the layer is 20% or more), the refractive index of the layer can be decreased. Also by this, a layer with a low refractive index can be formed inside the EL layer 103, and the external quantum efficiency of the light-emitting device can be improved.

[0122] By forming the hole injection layer 111, the injectability of holes becomes good, and a light-emitting device with a small driving voltage can be obtained.

[0123] Among substances having acceptor properties, organic compounds having acceptor properties are easy to use because they are easy to vapor-deposit and easy to form a film.

[0124] The hole transport layer 112 is formed by including a material having hole transporting property. As the material having hole transporting property, it preferably has a hole mobility of 1×10 -6 cm 2 / Vs or more.

[0125] Examples of the hole transporting material include compounds having an aromatic amine skeleton such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluorene-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 having a carbazole skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP); 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among those described above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. In addition, the substances listed as hole-transporting materials used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112.,

[0126] The light-emitting layer 113 has a light-emitting substance and a host material. Note that the light-emitting layer 113 may simultaneously contain other materials. Also, it may be a laminate of two layers with different compositions.

[0127] The light-emitting substance may be a fluorescent light-emitting substance, a phosphorescent light-emitting substance, a substance showing thermally activated delayed fluorescence (TADF), or any other light-emitting substance. Note that one aspect of the present invention can be more preferably applied when the light-emitting layer 113 is a layer showing fluorescent light emission, particularly a layer showing blue fluorescent light emission.

[0128] In the light-emitting layer 113, examples of materials that can be used as fluorescent light-emitting substances include the following. Other fluorescent light-emitting substances can also be used.

[0129] 5,6-Bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-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-diyl-di-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N''' - octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-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(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-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(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-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-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), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrenediyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, condensed aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 are preferred because they have high hole trapping properties and excellent luminous efficiency and reliability.,

[0130] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, examples of the materials that can be used include the following.

[0131] 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 )), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) 3 )), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) 3) organometallic iridium complexes having a 4H-triazole skeleton such as, tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) 3 ) tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) 3 ) organometallic iridium complexes having a 1H-triazole skeleton such as, fac-tris[(1-2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi) 3 ) tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) 3 ) organometallic iridium complexes having an imidazole skeleton such as, bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3’,5’-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’} iridium(III) picolinate (abbreviation: [Ir(CF 3 ppy) 2 (pic)]), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium(III) acetylacetonate (abbreviation: FIrracac) and the like, organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand. These are compounds that exhibit blue phosphorescent emission and have an emission peak in the wavelength range from 440 nm to 520 nm.

[0132] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3 ) tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 3 ) (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) 2 (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 2 (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) 2 (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm) 2 (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) 2 (acac)]), organometallic iridium complexes having a pyrimidine skeleton such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) 2 (acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) 2 (acac)]), organometallic iridium complexes having a pyrazine skeleton such as 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)]), in addition to organometallic iridium complexes having a pyridine skeleton such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) 3 (Phen)]). These are mainly compounds that exhibit green phosphorescent emission and have an emission peak in the wavelength range from 500 nm to 600 nm. In addition, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because of their outstanding reliability and luminescence efficiency.

[0133] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) 2 (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) 2 (dpm)]), bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm) 2 (dpm)]) and other organometallic iridium complexes having a pyrimidine skeleton, (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)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) 2 (acac)]) and other organometallic iridium complexes having a pyrazine skeleton, tris(1-phenylisoquinolinato-N,C2’ ) Iridium(III) (abbreviation: [Ir(piq) 3 ), bis(1-phenylisoquinolinato-N,C 2’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq) 2 (acac)]), in addition to organometallic iridium complexes having a pyridine skeleton such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), platinum complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM) 3 (Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) 3 (Phen)]) and other rare earth metal complexes. These are compounds that exhibit red phosphorescent emission and have an emission peak in the wavelength range from 600 nm to 700 nm. In addition, organometallic iridium complexes having a pyrazine skeleton can obtain red emission with good chromaticity.

[0134] In addition to the phosphorescent compounds described above, known phosphorescent compounds may be selected and used.

[0135] As the TADF material, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc. can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. can be mentioned. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF 2 (Proto IX)), mesoporphyrin-tin fluoride complex (SnF 2 (Meso IX)), hematoporphyrin-tin fluoride complex (SnF 2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF 2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF 2 (OEP)), etioporphyrin-tin fluoride complex (SnF 2 (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl 2 OEP), etc. can also be mentioned.

[0136]

Chemical formula

[0137] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ) represented by the following structural formula, 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc., heterocyclic compounds having one or both of a π-electron excess type heteroaromatic ring and a π-electron deficient type heteroaromatic ring can also be used. Since the heterocyclic compound has a π-electron excess type heteroaromatic ring and a π-electron deficient type heteroaromatic ring, it has both high electron transportability and hole transportability, which is preferable. Among them, among the skeletons having a π-electron deficient type heteroaromatic ring, a pyridine skeleton, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and a triazine skeleton are preferable because they are stable and have good reliability. In particular, a benzofuropyrimidine skeleton, a benzothienopyrimidine skeleton, a benzofuropyrazine skeleton, and a benzothienopyrazine skeleton are preferable because they have high acceptor properties and good reliability. Also, among the skeletons having a π-electron excess type heteroaromatic ring, an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton are stable and have good reliability, so it is preferable to have at least one of these skeletons.Note that as the furan skeleton, a dibenzofuran skeleton is preferable, and as the thiophene skeleton, a dibenzothiophene skeleton is preferable. Further, as the pyrrole skeleton, an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbaazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable. Note that a substance in which a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both a strong electron-donating property of the π-electron-excessive heteroaromatic ring and a strong electron-accepting property of the π-electron-deficient heteroaromatic ring, and the energy difference between the S1 level and the T1 level becomes small. Therefore, it is particularly preferable because thermally activated delayed fluorescence can be efficiently obtained. Note that instead of the π-electron-deficient heteroaromatic ring, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used. Further, as the π-electron-excessive skeleton, an aromatic amine skeleton, a phenazine skeleton, or the like can be used. Further, as the π-electron-deficient skeleton, 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 borantrene, an aromatic ring or a heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, or the like can be used. Thus, a π-electron-deficient skeleton and a π-electron-excessive skeleton can be used instead of at least one of the π-electron-deficient heteroaromatic ring and the π-electron-excessive heteroaromatic ring.

[0138]

Chemical formula

[0139] Note that a TADF material is a material having a function in which the difference between the S1 level and the T1 level is small and energy can be converted from triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, upconversion (reverse intersystem crossing) from triplet excitation energy to singlet excitation energy is possible with a small amount of thermal energy, and a singlet excited state can be efficiently generated. Further, triplet excitation energy can be converted into light emission.

[0140] In addition, an exciplex (also referred to as an exciplex, exiplex, or Exciplex) that forms an excited state with two types of substances has a very small difference between the S1 level and the T1 level and functions as a TADF material capable of converting triplet excitation energy into singlet excitation energy.

[0141] Note that as an index of the T1 level, a phosphorescence spectrum observed at a low temperature (for example, from 77 K to 10 K) may be used. As the TADF material, when a tangent is drawn at the trailing edge on the short-wavelength side of the fluorescence spectrum, the energy of the wavelength of the extrapolated line is taken as the S1 level, and a tangent is drawn at the trailing edge on the short-wavelength side of the phosphorescence spectrum, and the energy of the wavelength of the extrapolated line is taken as the T1 level, it is preferable that the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0142] When using a TADF material as a luminescent substance, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0143] As the host material of the light-emitting layer, various carrier transport materials such as materials having electron transport properties, materials having hole transport properties, and the above-mentioned TADF materials can be used.

[0144] As materials having hole transporting properties, organic compounds having an amine skeleton or a π-electron rich heteroaromatic ring skeleton are preferred. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF) and other compounds having an aromatic amine skeleton, 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) and other compounds having a carbazole skeleton, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) can be mentioned. Among those described above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Further, the organic compounds exemplified as materials having hole transportability in the hole transport layer 112 can also be used.,

[0145] Examples of materials having electron transportability include, for example, bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2) Metal complexes such as 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), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring skeleton are preferred. Examples of the organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-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) and other heterocyclic compounds having a polyazole skeleton, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3’-(9H-carbazol-9-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II) and other heterocyclic compounds having a diazine skeleton, 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,Heterocyclic compounds having a pyridine skeleton such as 5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluorene)-2-yl]-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), and other heterocyclic compounds having a triazine skeleton can be mentioned. Among those described above, heterocyclic compounds having a diazine skeleton, heterocyclic compounds having a pyridine skeleton, and heterocyclic compounds having a triazine skeleton are preferred because of their good reliability. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton and heterocyclic compounds having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0146] As the TADF material that can be used as a host material, those previously mentioned as TADF materials can be used in the same manner. When the TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted into singlet excitation energy by reverse intersystem crossing, and further energy transfer to the light-emitting substance can increase the luminous efficiency of the light-emitting device. At this time, the TADF material functions as an energy donor, and the light-emitting substance functions as an energy acceptor.

[0147] This is very effective when the above luminescent material is a fluorescent luminescent material. Also, at this time, in order to obtain high luminous efficiency, it is preferable that the S1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Further, it is preferable that the T1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than the T1 level of the fluorescent luminescent material.

[0148] Also, it is preferable to use a TADF material that emits light with a wavelength overlapping the wavelength of the absorption band on the lowest energy side of the fluorescent luminescent material. By doing so, the transfer of excitation energy from the TADF material to the fluorescent luminescent material becomes smooth, and light emission can be obtained efficiently, which is preferable.

[0149] In addition, in order to efficiently generate singlet excited energy from triplet excited energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. Further, it is preferable that the triplet excited energy generated in the TADF material does not transfer to the triplet excited energy of the fluorescent substance. For this purpose, it is preferable that the fluorescent substance has a protecting group around the lumophore (skeleton responsible for luminescence) possessed by the fluorescent substance. As the protecting group, a substituent having no π bond is preferable, a saturated hydrocarbon is preferable, and specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms can be mentioned. It is more preferable that there are a plurality of protecting groups. Since a substituent having no π bond has poor ability to transport carriers, it is possible to increase the distance between the TADF material and the lumophore of the fluorescent substance with little influence on carrier transport and carrier recombination. Here, the lumophore refers to an atomic group (skeleton) that causes luminescence in the fluorescent substance. The lumophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, and a phenothiazine skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton are preferable because they have a high fluorescence quantum yield.

[0150] When using a fluorescent light-emitting material as the light-emitting material, as the host material, a material having an anthracene skeleton is suitable. When using a substance having an anthracene skeleton as the host material of the fluorescent light-emitting material, it is possible to realize a light-emitting layer with good luminous efficiency and durability. As the substance having an anthracene skeleton used as the host material, a substance having a diphenylanthracene skeleton, particularly a substance having a 9,10-diphenylanthracene skeleton, is preferable because it is chemically stable. Further, when the host material has a carbazole skeleton, it is preferable because the hole injection and transport properties are enhanced. However, when it contains a benzocarbazole skeleton in which a benzene ring is further condensed with carbazole, the HOMO becomes about 0.1 eV shallower than that of carbazole, and holes can easily enter, so it is more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, the HOMO becomes about 0.1 eV shallower than that of carbazole, holes can easily enter, the hole transport property is excellent, and the heat resistance is also high, so it is suitable. Therefore, a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton) is more preferable as the host material. From the above viewpoints of hole injection and transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), etc.In particular, CzPA, cgDBCzPA2mBnfPPA, and PCzPA are preferred choices because they exhibit very good properties.

[0151] Note that the host material may be a material obtained by mixing multiple substances. When using a mixed host material, it is preferable to mix a material with electron transporting properties and a material with hole transporting properties. By mixing a material with electron transporting properties and a material with 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 content of the material with hole transporting properties to the material with electron transporting properties may be Hole transporting material : Electron transporting material = 1:19 to 19:1.

[0152] Note that a phosphorescent light-emitting substance can be used as part of the above-mentioned mixed material. The phosphorescent light-emitting substance can be used as an energy donor that supplies excitation energy to the fluorescent light-emitting substance when the fluorescent light-emitting substance is used as the light-emitting substance.

[0153] Also, an exciplex may be formed between these mixed materials. By selecting a combination that forms an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the light-emitting substance, energy transfer becomes smooth and efficient light emission can be obtained, which is preferable. Also, using this configuration is preferable because the driving voltage is also reduced.

[0154] Note that at least one of the materials forming the exciplex may be a phosphorescent light-emitting substance. By doing so, triplet excitation energy can be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0155] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the hole-transporting material is equal to or higher than the HOMO level of the electron-transporting material. Also, it is preferable that the LUMO level of the hole-transporting material is equal to or higher than the LUMO level of the electron-transporting material. Note that the LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0156] Note that the formation of the exciplex can be confirmed, for example, by comparing the emission spectrum of the hole-transporting material, the emission spectrum of the electron-transporting material, and the emission spectrum of a mixed film of these materials, and observing the phenomenon that the emission spectrum of the mixed film is shifted to a longer wavelength (or has a new peak on the longer wavelength side) than the emission spectra of the individual materials. Alternatively, the transient photoluminescence (PL) of the hole-transporting material, the transient PL of the electron-transporting material, and the transient PL of a mixed film of these materials are compared, and the difference in transient response such that the transient PL lifetime of the mixed film has a longer lifetime component or the ratio of the delayed component is increased is observed, whereby it can be confirmed. Also, the above-mentioned transient PL may be read as transient electroluminescence (EL). That is, the transient EL of the hole-transporting material, the transient EL of the electron-transporting material, and the transient EL of a mixed film of these are compared, and the formation of the exciplex can also be confirmed by observing the difference in transient response.

[0157] The electron transport layer 114 is a layer containing a substance having electron transporting properties. As the substance having electron transporting properties, those mentioned as the substances having electron transporting properties that can be used for the above host material can be used.

[0158] Also, the electron transport layer 114 has an electron mobility of 1×10 -7 cm 2 / Vs or more and 5×10 -5 cm 2It is preferably below / Vs. By reducing the electron transport property in the electron transport layer 114, the amount of electrons injected into the light-emitting layer can be controlled, and the light-emitting layer can be prevented from being in a state of excessive electrons. This configuration is particularly preferable because the lifetime is improved when the hole injection layer is formed of a composite material and the HOMO level of the material having hole transport property in the composite material is a substance having a relatively deep HOMO level of -5.7 eV or more and -5.4 eV or less. At this time, the material having electron transport property preferably has a HOMO level of -6.0 eV or more.

[0159] Also, in the electron transport layer 114, it is preferable that the alkali metal or the metal complex of the alkali metal has a concentration difference (including the case of 0) in the thickness direction.

[0160] Between the electron transport layer 114 and the cathode 102, as the electron injection layer 115, a layer containing an alkali metal or an alkaline earth metal or their compounds or complexes such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF 2 )), lithium 8-hydroxyquinolinate (abbreviation: Liq), etc. may be provided. The electron injection layer 115 may be a layer in which an alkali metal or an alkaline earth metal or their compounds are contained in a layer made of a substance having electron transport property, or an electride may be used. Examples of the electride include a substance obtained by adding electrons at a high concentration to a mixed oxide of calcium and aluminum.

[0161] In addition, as the electron injection layer 115, a layer in which the fluoride of the above alkali metal or alkaline earth metal is contained in a concentration equal to or higher than the concentration at which it becomes a microcrystalline state (50 wt% or more) in a substance having electron transport property (preferably an organic compound having a bipyridine skeleton) can also be used. Since the layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0162] Alternatively, a charge generation layer 116 may be provided instead of the electron injection layer 115 in FIG. 1A (FIG. 1B). The charge generation layer 116 is a layer capable of injecting holes into the layer in contact with the cathode side of the layer and electrons into the layer in contact with the anode side by applying a potential. 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 as a material capable of constituting the above-described 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 as materials constituting 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 102, and the light-emitting device operates.

[0163] Note that it is preferable that the charge generation layer 116 is 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.

[0164] The electron relay layer 118 contains at least a substance having electron transport properties and has a function of preventing the interaction between the electron injection buffer layer 119 and the P-type layer 117 and smoothly transferring electrons. The LUMO level of the substance having electron transport properties contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor substance in the P-type layer 117 and the LUMO level of the substance contained in the layer in contact with the charge generation layer 116 in the electron transport layer 114. The specific energy level of the LUMO level in the substance having electron transport properties used for the electron relay layer 118 is preferably -5.0 eV or higher, more preferably -5.0 eV or higher and -3.0 eV or lower. Note that as the substance having electron transport properties used for the electron relay layer 118, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0165] For the electron injection buffer layer 119, it is possible to use substances with high electron injection properties such as alkali metals, alkaline earth metals, rare earth metals, and their compounds (including alkali metal compounds (oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds (including oxides, halides, carbonates)).

[0166] Also, when the electron injection buffer layer 119 is formed by including a substance having electron transporting properties and a donor substance, as the donor substance, in addition to alkali metals, alkaline earth metals, rare earth metals, and their compounds (including alkali metal compounds (oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds (including oxides, halides, carbonates)), organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, and decamethylnickelocene can also be used.

[0167] Note that as the substance having electron transporting properties, it can be formed using the same material as the material constituting the electron transport layer 114 described above. Since the material is an organic compound with a low refractive index, by using it for the electron injection buffer layer 119, a light-emitting device with good external quantum efficiency can be obtained.

[0168] As the material for forming the cathode 102, metals, alloys, electroconductive compounds, and mixtures thereof having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer between the cathode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, indium tin oxide containing silicon or silicon oxide, etc. can be used as the cathode 102 regardless of the work function.

[0169] In addition, when the cathode 102 is formed of a material having permeability to visible light, a light-emitting device that emits light from the cathode side as shown in Fig. 1D can be obtained. When the anode 101 is formed on the substrate side in this light-emitting device, it can be a so-called top emission type light-emitting device.

[0170] These conductive materials can be formed into a film using dry methods such as vacuum evaporation and sputtering, inkjet methods, spin coating methods, etc. Also, it may be formed by a wet method using the sol-gel method, or may be formed by a wet method using a paste of a metal material.

[0171] In addition, as a method for forming the EL layer 103, various methods can be used regardless of dry methods or wet methods. For example, vacuum evaporation, gravure printing, offset printing, screen printing, inkjet methods, or spin coating methods may be used.

[0172] Also, the above-described respective electrodes or respective layers may be formed using different film-forming methods.

[0173] Note that the configuration of the layer provided between the anode 101 and the cathode 102 is not limited to the above. However, a configuration is preferred in which a light-emitting region where holes and electrons recombine is provided at a site distant from the anode 101 and the cathode 102 so as to suppress quenching caused by the proximity of the light-emitting region to the metal used for the electrode or the carrier injection layer.

[0174] In addition, the hole transport layer or the electron transport layer in contact with the light-emitting layer 113, particularly the carrier transport layer close to the recombination region in the light-emitting layer 113, is preferably composed of a material having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the band gap of the light-emitting material contained in the light-emitting layer in order to suppress energy transfer from the excitons generated in the light-emitting layer.

[0175] Subsequently, an embodiment of a light-emitting device having a configuration in which a plurality of light-emitting units are stacked (also referred to as a stacked element or a tandem element) will be described. This light-emitting device is a light-emitting device having a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has substantially the same configuration as the EL layer 103 shown in FIG. 1A. That is, the tandem element is a light-emitting device having a plurality of light-emitting units, and it can be said that the light-emitting device shown in FIG. 1A or FIG. 1B is a light-emitting device having one light-emitting unit.

[0176] In the tandem element, a first light-emitting unit and a second light-emitting unit are stacked between the anode and the cathode, and a charge generation layer is provided between the first light-emitting unit and the second light-emitting unit. The anode and the cathode respectively correspond to the anode 101 and the cathode 102 in FIG. 1A, and the same ones as those described in the description of FIG. 1A can be applied. Also, the first light-emitting unit and the second light-emitting unit may have the same configuration or different configurations from each other.

[0177] In a tandem element, the charge generation layer has a function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied between the anode and the cathode. That is, when a voltage is applied such that the potential of the anode is higher than the potential of the cathode, the charge generation layer may inject electrons into the first light-emitting unit and holes into the second light-emitting unit.

[0178] The charge generation layer is preferably formed with the same configuration as the charge generation layer 116 described in FIG. 1B. Since the composite material of the organic compound and the metal oxide is excellent in carrier injection property and carrier transport property, low-voltage driving and low-current driving can be realized. When the surface on the anode side of the light-emitting unit is in contact with the charge generation layer, the charge generation layer can also serve as the hole injection layer of the light-emitting unit, so the light-emitting unit does not necessarily need to be provided with a hole injection layer.

[0179] When an electron injection buffer layer 119 is provided in the charge generation layer of the tandem element, since the electron injection buffer layer 119 serves as the electron injection layer in the light-emitting unit on the anode side, it is not always necessary to form an electron injection layer in the light-emitting unit on the anode side.

[0180] As described above, the tandem element having two light-emitting units has been described, but the same can be similarly applied to a tandem element in which three or more light-emitting units are stacked. By arranging a plurality of light-emitting units between a pair of electrodes partitioned by a charge generation layer, high-brightness light emission can be enabled while keeping the current density low, and a longer-life element can be realized. In addition, a light-emitting device capable of low-voltage driving and having low power consumption can be realized.

[0181] Also, by making the emission colors of the respective light-emitting units different, light emission of a desired color can be obtained for the entire light-emitting device. For example, in a light-emitting device having two light-emitting units, by obtaining red and green emission colors in the first light-emitting unit and a blue emission color in the second light-emitting unit, it is also possible to obtain a light-emitting device that emits white light as the entire light-emitting device.

[0182] In addition, each layer and electrode such as the above-described EL layer 103, the first light-emitting unit, the second light-emitting unit, and the charge generation layer can be formed, for example, by methods such as vapor deposition (including vacuum vapor deposition), droplet ejection method (also referred to as inkjet method), coating method, gravure printing method, etc. Further, they may contain low molecular weight materials, medium molecular weight materials (including oligomers and dendrimers), or high molecular weight materials.

[0183] In addition, the present embodiment can be freely combined with other embodiments.

[0184] (Embodiment 2) In this embodiment, a light-emitting device using the light-emitting device described in Embodiment 1 will be described.

[0185] In this embodiment, a light-emitting device manufactured using the light-emitting device described in Embodiment 1 will be described with reference to FIGS. 2A and 2B. Note that FIG. 2A is a top view showing the light-emitting device, and FIG. 2B is a cross-sectional view taken along the dashed-dotted lines A-B and C-D shown in FIG. 2A. This light-emitting device includes a drive circuit unit (source line drive circuit) 601, a pixel unit 602, and a drive circuit unit (gate line drive circuit) 603, which are indicated by dotted lines, for controlling the light emission of the light-emitting device. Further, 604 is a sealing substrate, and 605 is a sealing material. The inside surrounded by the sealing material 605 is a space 607.

[0186] Note that the routing wiring 608 is a wiring for transmitting signals input to the source line drive circuit 601 and the gate line drive circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, etc. from an FPC (flexible printed circuit) 609 serving as an external input terminal. Although only the FPC is illustrated here, a printed wiring board (PWB) may be attached to this FPC. The light-emitting device in this specification includes not only the light-emitting device main body but also a state in which an FPC or a PWB is attached thereto.

[0187] Next, the cross-sectional structure will be described with reference to FIG. 2B. A drive circuit section and a pixel section are formed on the element substrate 610. Here, a source line drive circuit 601, which is a drive circuit section, and one pixel in the pixel section 602 are shown.

[0188] The element substrate 610 may be made of a substrate such as glass, quartz, organic resin, metal, alloy, semiconductor, etc., or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic resin, etc.

[0189] The structure of the transistors used in the pixels and drive circuits is not particularly limited. For example, it may be an inverted staggered transistor or a staggered transistor. Also, it may be a top gate transistor or a bottom gate transistor. The semiconductor material used for the transistors is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, etc. can be used. 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.

[0190] The crystallinity of the semiconductor material used for the transistors is also not particularly limited, and any of an amorphous semiconductor, a semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or a semiconductor having a crystal region in part) may be used. Using a semiconductor having crystallinity is preferable because deterioration of transistor characteristics can be suppressed.

[0191] Here, in addition to the transistors provided in the above pixels and drive circuits, for semiconductor devices such as transistors used in touch sensors described later, it is preferable to apply an oxide semiconductor. In particular, it is preferable to apply an oxide semiconductor having a wider bandgap than silicon. By using an oxide semiconductor having a wider bandgap than silicon, the current in the off state of the transistor can be reduced.

[0192] The above oxide semiconductor preferably contains at least indium (In) or zinc (Zn). More preferably, it is an oxide semiconductor containing an oxide represented by In-M-Zn system oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce or Hf).

[0193] In particular, as the semiconductor layer, it is preferable to use an oxide semiconductor film having a plurality of crystal parts, wherein the c-axis of the crystal part is oriented perpendicular to the surface to be formed of the semiconductor layer or the upper surface of the semiconductor layer, and there is no grain boundary between adjacent crystal parts.

[0194] By using such a material as the semiconductor layer, fluctuations in electrical characteristics can be suppressed, and a highly reliable transistor can be realized.

[0195] In addition, due to the low off-current of the transistor having the above semiconductor layer, it is possible to hold the charge accumulated in the capacitor through the transistor for a long period of time. By applying such a transistor to a pixel, it is also possible to stop the drive circuit while maintaining the gradation of the image displayed in each display area. As a result, an electronic device with extremely low power consumption can be realized.

[0196] For the purpose of stabilizing the characteristics of the transistor, etc., it is preferable to provide an underlayer film. As the underlayer film, an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film can be used, and it can be formed as a single layer or by lamination. 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, a MOCVD (Metal Organic CVD) method, etc.), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, etc. Note that the underlayer film may not be provided if not necessary.

[0197] Note that FET623 indicates one of the transistors formed in the drive circuit section 601. Also, the drive circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. Further, in this embodiment, a driver integrated type in which the drive circuit is formed on the substrate is shown, but this is not necessarily required, and the drive circuit can also be formed outside the substrate instead of on the substrate.

[0198] Also, the pixel section 602 is formed of a plurality of pixels including a switching FET611, a current control FET612, and an anode 613 electrically connected to its drain, but is not limited thereto, and may be a pixel section combining three or more FETs and a capacitive element.

[0199] Note that an insulator 614 is formed covering the end of the anode 613. Here, it can be formed by using a positive photosensitive acrylic resin film.

[0200] Also, in order to make the coating property of the EL layer or the like formed later good, a curved surface having a curvature is formed at the upper end or the lower end of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material of the insulator 614, it is preferable to provide a curved surface having a curvature radius (0.2 μm to 3 μm) only at the upper end of the insulator 614. Also, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0201] An EL layer 616 and a cathode 617 are respectively formed on the anode 613. Here, as the material used for the anode 613, it is desirable to use a material with a large work function. For example, in addition to single-layer films such as ITO films, indium tin oxide films containing silicon, indium oxide films containing 2 to 20 wt% of zinc oxide, titanium nitride films, chromium films, tungsten films, Zn films, Pt films, etc., a laminate of a titanium nitride film and a film mainly composed of aluminum, a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film can be used. Note that when a laminated structure is used, the resistance as a wiring is low, good ohmic contact can be achieved, and it can further function as an anode.

[0202] In addition, the EL layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an inkjet method, and a spin coating method. The EL layer 616 includes the configuration as described in Embodiment 1. Further, as other materials constituting the EL layer 616, low molecular compounds or high molecular compounds (including oligomers and dendrimers) may be used.

[0203] Furthermore, the material used for the cathode 617, which is formed on the EL layer 616, is preferably a material with a small work function (Al, Mg, Li, Ca, or alloys or compounds thereof (such as MgAg, MgIn, AlLi, etc.)). Note that when the light generated in the EL layer 616 passes through the cathode 617, it is preferable to use a laminate of a thin metal film with a reduced film thickness and a transparent conductive film (ITO, indium oxide containing 2 to 20 wt% of zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) as the cathode 617.

[0204] Note that a light-emitting device is formed by the anode 613, the EL layer 616, and the cathode 617. The light-emitting device is the light-emitting device described in Embodiment 1. Note that the pixel portion is formed of a plurality of light-emitting devices. In the light-emitting device of this embodiment, both the light-emitting device described in Embodiment 1 and light-emitting devices having other configurations may be mixed.

[0205] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, a structure is formed in which the light-emitting device 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. Note that the space 607 is filled with a filling material, and in addition to the case where an inert gas (such as nitrogen or argon) is filled, it may be filled with a sealing material. It is a preferable configuration to form a concave portion in the sealing substrate and provide a drying material therein to suppress deterioration due to the influence of moisture.

[0206] Note that it is preferable to use an epoxy resin or glass frit for the sealing material 605. Further, it is desirable that these materials are materials that hardly transmit moisture and oxygen. In addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic resin, or the like can be used as the material for the sealing substrate 604.

[0207] Although not shown in FIGS. 2A and 2B, a protective film may be provided on the cathode. The protective film may be formed of an organic resin film or an inorganic insulating film. Further, the protective film may be formed so as to cover the exposed portion of the sealing material 605. Further, the protective film can be provided so as to cover the exposed side surfaces of the surfaces and side surfaces of the pair of substrates, the sealing layer, the insulating layer, and the like.

[0208] A material that hardly transmits impurities such as water can be used for the protective film. Therefore, it is possible to effectively suppress the diffusion of impurities such as water from the outside to the inside.

[0209] As materials for forming the protective film, oxides, nitrides, fluorides, sulfides, ternary compounds, metals, polymers, etc. can be used. For example, materials 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, etc., materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, etc., nitrides containing titanium and aluminum, oxides containing titanium and aluminum, oxides containing aluminum and zinc, sulfides containing manganese and zinc, sulfides containing cerium and strontium, oxides containing erbium and aluminum, oxides containing yttrium and zirconium, etc. can be used.

[0210] The protective film is preferably formed using a film formation method with good step coverage. One such method is the atomic layer deposition (ALD) method. It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, a protective film that is dense, has reduced defects such as cracks and pinholes, or has a uniform thickness can be formed. Also, the damage to the processing member when forming the protective film can be reduced.

[0211] For example, by forming the protective film using the ALD method, a protective film that is uniform and has few defects can be formed on the surface with a complex uneven shape, as well as on the upper, side, and back surfaces of the touch panel.

[0212] In the above manner, a light-emitting device manufactured using the light-emitting device described in Embodiment 1 can be obtained.

[0213] Since the light-emitting device according to this embodiment uses the light-emitting device described in Embodiment 1, a light-emitting device with good characteristics can be obtained. Specifically, since the light-emitting device described in Embodiment 1 has good luminous efficiency, it is possible to obtain a light-emitting device with low power consumption.

[0214] FIGS. 3A and 3B show examples of a light-emitting device that forms a light-emitting device exhibiting white light emission and is colorized by providing a coloring layer (color filter) or the like. FIG. 3A shows a substrate 1001, an underlying insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, anodes 1024W, 1024R, 1024G, 1024B of the light-emitting device, a partition wall 1025, an EL layer 1028, a cathode 1029 of the light-emitting device, a sealing substrate 1031, a sealing material 1032, etc.

[0215] In FIG. 3A, the coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) are provided on a transparent base material 1033. Also, a black matrix 1035 may be further provided. The transparent base material 1033 provided with the coloring layer and the black matrix is aligned and fixed to the substrate 1001. Note that the coloring layer and the black matrix 1035 are covered with an overcoat layer 1036. In FIG. 3A, there are a light-emitting layer where light does not pass through the coloring layer and exits to the outside, and a light-emitting layer where light passes through the coloring layers of each color and exits to the outside. Since the light that does not pass through the coloring layer is white, and the light that passes through the coloring layer is red, green, or blue, an image can be expressed with four-color pixels.

[0216] FIG. 3B shows an example in which the coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. In this way, the coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.

[0217] In addition, in the light-emitting device described above, a light-emitting device having a structure that extracts light from the substrate 1001 side where the FET is formed (bottom emission type) is used. However, a light-emitting device having a structure that extracts light emission from the sealing substrate 1031 side (top emission type) may also be used. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, a substrate that does not transmit light can be used as the substrate 1001. Until a connection electrode connecting the FET and the anode of the light-emitting device is formed, it is formed in the same manner as the bottom emission type light-emitting device. Thereafter, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may serve as a planarization film. The third interlayer insulating film 1037 can be formed using other known materials in addition to the same material as the second interlayer insulating film.

[0218] The anodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are referred to as anodes here, but they may be cathodes. Further, in the case of a top emission type light-emitting device as shown in FIG. 4, it is preferable that the anode is a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described as the EL layer 103 in Embodiment 1, and an element structure capable of obtaining white light emission is adopted.

[0219] In the top emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black matrix may be covered with an overcoat layer 1036. Note that a substrate having translucency is used as the sealing substrate 1031. Here, an example of full-color display using four colors of red, green, blue, and white is shown, but it is not particularly limited, and full-color display may be performed using four colors of red, yellow, green, and blue or three colors of red, green, and blue.

[0220] In a top emission type light emitting device, the application of a microcavity structure can be preferably carried out. A light emitting device having a microcavity structure can be obtained by using a reflective electrode as the anode and a semi-transmissive / semi-reflective electrode as the cathode. Between the reflective electrode and the semi-transmissive / semi-reflective electrode, there is at least an EL layer and at least a light emitting layer serving as a light emitting region.

[0221] Note that the reflective electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100%, and its resistivity is a film of 1×10 -2 Ωcm or less. Also, the semi-transmissive / semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and its resistivity is a film of 1×10 -2 Ωcm or less.

[0222] The light emitted from the light emitting layer included in the EL layer is reflected and resonated by the reflective electrode and the semi-transmissive / semi-reflective electrode.

[0223] The optical distance between the reflective electrode and the semi-transmissive / semi-reflective electrode of the light emitting device can be changed by changing the thicknesses of a transparent conductive film, the above-mentioned composite material, a carrier transport material, etc. Thereby, between the reflective electrode and the semi-transmissive / semi-reflective electrode, light of a resonating wavelength can be enhanced and light of a non-resonating wavelength can be attenuated.

[0224] Note that since the light (first reflected light) reflected by the reflective electrode and returning causes significant interference with the light (first incident light) directly incident from the light emitting layer to the semi-transmissive / semi-reflective electrode, it is preferable to adjust the optical distance between the reflective electrode and the light emitting layer to (2n - 1)λ / 4 (where n is a natural number of 1 or more and λ is the wavelength of the light to be amplified). By adjusting the optical distance, the phases of the first reflected light and the first incident light can be matched and the light emission from the light emitting layer can be further amplified.

[0225] In the above configuration, the EL layer may have a structure with a plurality of light-emitting layers or a structure with a single light-emitting layer. For example, in combination with the configuration of the tandem light-emitting device described above, a plurality of EL layers may be provided with a charge generation layer sandwiched between them in one light-emitting device, and the configuration may be applied to form one or more light-emitting layers in each EL layer.

[0226] By having a microcavity structure, it is possible to enhance the light emission intensity in the front direction of a specific wavelength, so that power consumption can be reduced. In the case of a light-emitting device that displays an image with four sub-pixels of red, yellow, green, and blue, in addition to the luminance improvement effect by yellow light emission, a microcavity structure adapted to the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with good characteristics.

[0227] Since the light-emitting device in the present embodiment uses the light-emitting device described in Embodiment 1, a light-emitting device having good characteristics can be obtained. Specifically, since the light-emitting device described in Embodiment 1 has good luminous efficiency, it is possible to obtain a light-emitting device with low power consumption.

[0228] So far, the active matrix light-emitting device has been described. From the following, a passive matrix light-emitting device will be described. FIGS. 5A and 5B show a passive matrix light-emitting device fabricated by applying the present invention. Note that FIG. 5A is a perspective view showing the light-emitting device, and FIG. 5B is a cross-sectional view taken along the dashed line X-Y in FIG. 5A. In FIG. 5, an EL layer 955 is provided between an electrode 952 and an electrode 956 on a substrate 951. The end of the electrode 952 is covered with an insulating layer 953. Then, a partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall becomes narrower as it approaches the substrate surface. That is, the cross-section in the short side direction of the partition layer 954 is trapezoidal, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in the passive matrix light-emitting device, the light-emitting device described in Embodiment 1 is used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained.

[0229] As described above, the light-emitting device can control each of a large number of minute light-emitting devices arranged in a matrix, and thus is a light-emitting device that can be suitably used as a display device for image display.

[0230] Also, this embodiment can be freely combined with other embodiments.

[0231] (Embodiment 3) In this embodiment, an example in which the light-emitting device described in Embodiment 1 is used as an illumination device will be described with reference to FIG. 6. FIG. 6B is a top view of the illumination device, and FIG. 6A is a cross-sectional view taken along the line segment e-f shown in FIG. 6B.

[0232] In the lighting device according to this embodiment, an anode 401 is formed on a translucent substrate 400 serving as a support. The anode 401 corresponds to the anode 101 in Embodiment 1. When extracting light emission from the anode 401 side, the anode 401 is formed of a translucent material.

[0233] A pad 412 for supplying voltage to the cathode 404 is formed on the substrate 400.

[0234] An EL layer 403 is formed on the anode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1. For the description of these configurations, please refer to the relevant description.

[0235] The cathode 404 is formed to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 in Embodiment 1. When extracting light emission from the anode 401 side, the cathode 404 is formed of a material with high reflectivity. The cathode 404 is connected to the pad 412 to supply voltage.

[0236] As described above, the lighting device in this embodiment has a light-emitting device having an anode 401, an EL layer 403, and a cathode 404. Since the light-emitting device has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption.

[0237] The lighting device is completed by fixing and sealing the substrate 400 on which the light-emitting device having the above configuration is formed and a sealing substrate 407 using sealing materials 405 and 406. Either of the sealing materials 405 and 406 can be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6B), whereby moisture can be adsorbed, leading to an improvement in reliability.

[0238] Also, by extending a part of the pad 412 and the anode 401 outside the sealing materials 405 and 406, it can be used as an external input terminal. Also, an IC chip 420 with a converter or the like mounted thereon can be provided.

[0239] As described above, the lighting device according to the present embodiment uses the light-emitting device described in Embodiment 1 for the EL element, and can be a light-emitting device with low power consumption.

[0240] In addition, this embodiment can be freely combined with other embodiments.

[0241] (Embodiment 4) In this embodiment, an example of an electronic device including the light-emitting device described in Embodiment 1 in a part thereof will be described. The light-emitting device described in Embodiment 1 is a light-emitting device with good luminous efficiency and low power consumption. As a result, the electronic device described in this embodiment can be an electronic device having a light-emitting part with low power consumption.

[0242] Examples of the electronic device to which the above light-emitting device is applied include, for example, a television device (also referred to as a TV or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio playback device, and a large game machine such as a pachinko machine. Specific examples of these electronic devices are shown below.

[0243] FIG. 7A shows an example of a television device. In the television device, a display unit 7103 is incorporated in a housing 7101. Here, a configuration in which the housing 7101 is supported by a stand 7105 is shown. The display unit 7103 can display an image, and the display unit 7103 is configured by arranging the light-emitting devices described in Embodiment 1 in a matrix.

[0244] The operation of the television apparatus can be performed by operation switches provided in the housing 7101 or by a separate remote control unit 7110. Channel and volume operations can be performed by operation keys 7109 provided in the remote control unit 7110, and the video displayed on the display unit 7103 can be operated. Further, the remote control unit 7110 may be configured to include a display unit 7107 that displays information output from the remote control unit 7110. Note that the display device described in Embodiment 1 arranged in a matrix can also be applied to the display unit 7107.

[0245] Note that the television apparatus is configured to include a receiver, a modem, and the like. The receiver can receive general television broadcasts, and by connecting to a communication network by wire or wirelessly via the modem, one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers) information communication can also be performed.

[0246] FIG. 7B1 shows a computer, which includes a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. Note that this computer is manufactured by arranging the light-emitting devices described in Embodiment 1 in a matrix and using them for the display unit 7203. The computer shown in FIG. 7B1 may be in the form shown in FIG. 7B2. In the computer shown in FIG. 7B2, a display unit 7210 is provided instead of the keyboard 7204 and the pointing device 7206. The display unit 7210 is a touch panel type, and input can be performed by operating the input display shown on the display unit 7210 with a finger or a dedicated pen. Further, the display unit 7210 can display not only the input display but also other images. The display unit 7203 may also be a touch panel. By connecting the two screens with a hinge, it is possible to prevent problems such as damage or breakage of the screens during storage or transportation.

[0247] FIG. 7C shows an example of a mobile terminal. The mobile phone includes, in addition to a display unit 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone has a display unit 7402 formed by arranging the light-emitting devices described in Embodiment 1 in a matrix pattern.

[0248] The mobile terminal shown in FIG. 7C can be configured such that information can be input by touching the display unit 7402 with a finger or the like. In this case, operations such as making a call or creating an e-mail can be performed by touching the display unit 7402 with a finger or the like.

[0249] The screen of the display unit 7402 mainly has three modes. The first is a display mode mainly for displaying images, the second is an input mode mainly for inputting information such as characters, and the third is a display + input mode in which the two modes of the display mode and the input mode are mixed.

[0250] For example, when making a call or creating an e-mail, the display unit 7402 may be set to a character input mode mainly for inputting characters, and an input operation of the characters displayed on the screen may be performed. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402.

[0251] In addition, by providing a detection device having sensors such as a gyro and an acceleration sensor for detecting the inclination inside the mobile terminal, the orientation (portrait or landscape) of the mobile terminal can be determined, and the screen display of the display unit 7402 can be automatically switched.

[0252] In addition, the screen mode can be switched by touching the display unit 7402 or operating the operation buttons 7403 of the housing 7401. It can also be switched according to the type of image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it is switched to the display mode, and if it is text data, it is switched to the input mode.

[0253] Also, in the input mode, when detecting a signal detected by the light sensor of the display unit 7402 and there is no input by a touch operation on the display unit 7402 for a certain period, it may be controlled to switch the screen mode from the input mode to the display mode.

[0254] The display unit 7402 can also function as an image sensor. For example, by touching the display unit 7402 with a palm or a finger and imaging a palm print, a fingerprint, etc., personal authentication can be performed. Also, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used in the display unit, finger veins, palm veins, etc. can also be imaged.

[0255] Note that the configurations shown in this embodiment can be used by appropriately combining the configurations shown in Embodiments 1 to 4.

[0256] As described above, the application range of the light-emitting device including the light-emitting device described in Embodiment 1 or Embodiment 2 is extremely wide, and this light-emitting device can be applied to electronic devices in all fields. By using the light-emitting device described in Embodiment 1 or Embodiment 2, an electronic device with low power consumption can be obtained.

[0257] FIG. 8A is a schematic diagram showing an example of a cleaning robot.

[0258] The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, the lower surface of the cleaning robot 5100 is provided with tires, a suction port, etc. The cleaning robot 5100 is further provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. Also, the cleaning robot 5100 is provided with wireless communication means.

[0259] The cleaning robot 5100 can travel automatically, detect dust 5120, and suck dust from the suction port provided on the lower surface.

[0260] In addition, the cleaning robot 5100 can analyze the images captured by the camera 5102 to determine the presence or absence of obstacles such as walls, furniture, or steps. Further, when an object that is likely to get caught in the brush 5103, such as wiring, is detected by image analysis, the rotation of the brush 5103 can be stopped.

[0261] The display 5101 can display the remaining battery level, the amount of dust sucked, etc. The path traveled by the cleaning robot 5100 may also be displayed on the display 5101. Further, the display 5101 may be a touch panel, and the operation buttons 5104 may be provided on the display 5101.

[0262] The cleaning robot 5100 can communicate with a mobile electronic device 5140 such as a smartphone. The images captured by the camera 5102 can be displayed on the mobile electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when away from home. Also, the display on the display 5101 can be confirmed on a mobile electronic device such as a smartphone.

[0263] The light-emitting device according to one aspect of the present invention can be used for the display 5101.

[0264] The robot 2100 shown in FIG. 8B includes an arithmetic unit 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a moving mechanism 2108.

[0265] The microphone 2102 has a function of detecting the user's voice and environmental sounds, etc. Also, the speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104.

[0266] The display 2105 has a function of displaying various information. The robot 2100 can display the information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. Further, the display 2105 may be a removable information terminal, and by installing it at a fixed position of the robot 2100, charging and data transfer are enabled.

[0267] The upper camera 2103 and the lower camera 2106 have a function of imaging the surroundings of the robot 2100. Further, the obstacle sensor 2107 can detect the presence or absence of obstacles in the traveling direction when the robot 2100 moves forward using the moving mechanism 2108. The robot 2100 can recognize the surrounding environment and move safely using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107. The light-emitting device according to one aspect of the present invention can be used for the display 2105.

[0268] FIG. 8C is a diagram showing an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, a connection terminal 5006, a sensor 5007 (including a function of measuring 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 5008, a display unit 5002, a support unit 5012, earphones 5013, and the like.

[0269] The light-emitting device according to one aspect of the present invention can be used for the display unit 5001 and the second display unit 5002.

[0270] FIG. 9 is an example in which the light-emitting device described in Embodiment 1 is used in an electric stand which is a lighting device. The electric stand shown in FIG. 9 has a housing 2001 and a light source 2002, and as the light source 2002, the lighting device described in Embodiment 3 may be used.

[0271] FIG. 10 shows an example in which the light-emitting device described in Embodiment 1 is used as an indoor lighting device 3001. Since the light-emitting device described in Embodiment 1 is a light-emitting device with high luminous efficiency, it can be made into a lighting device with low power consumption. In addition, since the light-emitting device described in Embodiment 1 can be made into a large area, it can be used as a large-area lighting device. Further, since the light-emitting device described in Embodiment 1 is thin, it can be used as a thin lighting device.

[0272] The light-emitting device described in Embodiment 1 can also be mounted on the windshield or dashboard of an automobile. FIG. 11 shows one aspect in which the light-emitting device described in Embodiment 1 is used on the windshield or dashboard of an automobile. Display areas 5200 to 5203 are displays provided using the light-emitting device described in Embodiment 1.

[0273] Display area 5200 and display area 5201 are display devices equipped with the light-emitting device described in Embodiment 1 provided on the windshield of an automobile. By fabricating the anode and cathode of the light-emitting device described in Embodiment 1 with translucent electrodes, it can be made into a so-called see-through display device where the opposite side can be seen through. For a see-through display, even if it is installed on the windshield of an automobile, it can be installed without obstructing the view. When providing a transistor or the like for driving, it is preferable to use a translucent transistor such as an organic transistor made of an organic semiconductor material or a transistor using an oxide semiconductor.

[0274] The display area 5202 is a display device equipped with the light-emitting device described in Embodiment 1 provided in the pillar portion. By projecting the video from the imaging means provided on the vehicle body, the display area 5202 can complement the field of view blocked by the pillar. Similarly, the display area 5203 provided in the dashboard portion can complement the blind spot and enhance safety by projecting the video from the imaging means provided outside the vehicle to compensate for the field of view blocked by the vehicle body. By projecting the video so as to complement the invisible part, it is possible to perform safety confirmation more naturally and without discomfort.

[0275] The display area 5203 can also provide various information by displaying navigation information, speedometers, tachometers, air conditioner settings, etc. The display can be appropriately changed in terms of its display items and layout according to the user's preference. Note that this information can also be provided in the display areas 5200 to 5202. In addition, the display areas 5200 to 5203 can also be used as lighting devices.

[0276] Also, FIGS. 12A and 12B show a foldable portable information terminal 5150. The foldable portable information terminal 5150 has a housing 5151, a display area 5152, and a bending portion 5153. FIG. 12A shows the portable information terminal 5150 in the unfolded state. FIG. 12B shows the portable information terminal in the folded state. Despite having a large display area 5152, the portable information terminal 5150 is compact and highly portable when folded.

[0277] The display area 5152 can be folded in half by the bending portion 5153. The bending portion 5153 is composed of an expandable member and a plurality of support members. When folding, the expandable member extends. The bending portion 5153 is folded with a radius of curvature of 2 mm or more, preferably 3 mm or more.

[0278] Note that the display region 5152 may be a touch panel (input / output device) equipped with a touch sensor (input device). The light-emitting device of one embodiment of the present invention can be used for the display region 5152.

[0279] 13A to 13C show a foldable portable information terminal 9310. Fig. 13A shows the portable information terminal 9310 in an unfolded state. Fig. 13B shows the portable information terminal 9310 in a state in the process of changing from one of the unfolded state and the folded state to the other. Fig. 13C shows the portable information terminal 9310 in a folded state. The portable information terminal 9310 has excellent portability in a folded state, and has excellent viewability of the display due to a seamless wide display area in an unfolded state.

[0280] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). The display panel 9311 can be reversibly transformed from an unfolded state of the mobile information terminal 9310 to a folded state by bending the two housings 9315 via the hinges 9313. The light-emitting device of one embodiment of the present invention can be used for the display panel 9311. EXAMPLES

[0281] In this example, a light-emitting device 1 according to one embodiment of the present invention described in the embodiment and comparative light-emitting devices 1 to 3 will be described. The structural formulae of organic compounds used in this example are shown below.

[0282] [ka]

[0283] (Method of fabricating light-emitting device 1) First, on a glass substrate, as a reflective electrode, silver (Ag) was deposited by sputtering to a film thickness of 100 nm. Then, as a transparent electrode, indium tin oxide (ITSO) containing silicon oxide was deposited by sputtering to a film thickness of 10 nm to form the anode 101. The electrode area was 4 mm 2 (2 mm × 2 mm).

[0284] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0285] After that, the substrate was introduced into a vacuum evaporation apparatus whose interior was evacuated to about 10 -4 Pa, and in the heating chamber of the vacuum evaporation apparatus, vacuum baking was performed at 170 °C for 30 minutes. Then, the substrate was allowed to cool for about 30 minutes.

[0286] Next, with the surface on which the anode 101 was formed facing downward, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus. On the anode 101, N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: mmtBumTPoFBi-02) represented by the above structural formula (i) and an electron acceptor material (OCHD-001) were co-evaporated at a weight ratio of 1:0.1 (= mmtBumTPoFBi-02:OCHD-001) to a thickness of 10 nm to form the hole injection layer 111.

[0287] On the hole injection layer 111, mmtBumTPoFBi-02 was evaporated to a thickness of 130 nm to form the hole transport layer 112.

[0288] Subsequently, on the hole transport layer 112, 4-(dibenzothiophen-4-yl)-4'-phenyl-4''-(9-phenyl-9H-carbazol-2-yl)triphenylamine (abbreviation: PCBBiPDBt-02) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form an electron blocking layer.

[0289] Thereafter, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA) represented by the above structural formula (iii) and 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (iv) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (=Bnf(II)PhA:3,10PCA2Nbf(IV)-02) to form the light-emitting layer 113.

[0290] Thereafter, 2-[3’-(9,9-dimethyl-9H-fluoren-2-yl)-1,1’-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn) represented by the above structural formula (v) was evaporated to a thickness of 10 nm to form a hole-blocking layer. Then, 2-{(3’,5’-di-tert-butyl)-1,1’-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumBPTzn) represented by the above structural formula (vi) and lithium 6-methyl-8-quinolinolate (abbreviation: Li-6mq) represented by the above structural formula (vii) were co-evaporated at 20 nm so that the weight ratio was 1:1 (=mmtBumBPTzn:Li-6mq) to form the electron transport layer 114.

[0291] After the formation of the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form an electron injection layer 115. Finally, the cathode 102 was formed by co-evaporating silver (Ag) and magnesium (Mg) at a volume ratio of 1:0.1 and a film thickness of 15 nm to fabricate the light-emitting device 1. Note that the cathode 102 is a semi-transmissive / semi-reflective electrode having a function of reflecting light and a function of transmitting light, and the light-emitting device of this example is a top-emission type device that extracts light from the cathode 102. Further, 1,3,5-tri(dibenzothiophen-4-yl)-benzene (abbreviation: DBT3P-II) represented by the above structural formula (viii) was deposited on the cathode 102 to a thickness of 70 nm to improve the extraction efficiency.

[0292] (Fabrication method of Comparative Light-emitting Device 1) Comparative Light-emitting Device 1 was fabricated in the same manner as Light-emitting Device 1, except that mmtBumTPoFBi-02 in Light-emitting Device 1 was changed to N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF) represented by the above structural formula (ix), and the film thickness of the hole transport layer was set to 115 nm.

[0293] (Fabrication method of Comparative Light-emitting Device 2) Comparative Light-emitting Device 2 was fabricated in the same manner as Light-emitting Device 1, except that mmtBumBPTzn in the electron transport layer of Light-emitting Device 1 was changed to 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn) represented by the above structural formula (vx), and Li-6mq was changed to lithium 8-quinolinolate (abbreviation: Liq) represented by the above structural formula (x).

[0294] (Fabrication method of Comparative Light-emitting Device 3) Comparative Light-emitting Device 3 was fabricated in the same manner as Light-emitting Device 1, except that mmtBumTPoFBi-02 in Light-emitting Device 1 was changed to PCBBiF, the film thickness of the hole transport layer was set to 115 nm, mmtBumBPTzn in the electron transport layer was changed to mPn-mDMePyPTzn, and Li-6mq was changed to Liq.

[0295] The device structures of Light-emitting Device 1 and Comparative Light-emitting Devices 1 to 3 are summarized in the following table.

[0296]

Table 1

[0297] Also, the refractive indices of mmtBumTPoFBi-02 and PCBBiF are shown in Fig. 20, the refractive indices of mmtBumBPTzn, mPn-mDMePyPTzn, Li-6mq and Liq are shown in Fig. 21, and the refractive indices at 456 nm are shown in the following table. The measurements were carried out using a spectroscopic ellipsometer (M-2000U manufactured by J. A. Woolam Japan Co., Ltd.). As the measurement samples, films formed by vacuum deposition of about 50 nm of each layer material on a quartz substrate were used. In the figures, the refractive index of the ordinary ray n Ordinary and the refractive index of the extraordinary ray n Extra-ordinary are described.

[0298] From the figure, it can be seen that for mmtBumTPoFBi-02, the ordinary-ray refractive index is in the range of 1.69 to 1.70 and 1.50 or more and 1.75 or less throughout the blue light emission region (455 nm or more and 465 nm or less), and the ordinary-ray refractive index at 633 nm is also 1.64 and in the range of 1.45 or more and 1.70 or less. It was found that mmtBumTPoFBi-02 is a material with a low refractive index. Also, for mmtBumBPTzn, the ordinary-ray refractive index is 1.68 throughout the blue light emission region (455 nm or more and 465 nm or less) and is in the range of 1.50 or more and 1.75 or less. The ordinary-ray refractive index at 633 nm is also 1.64 and is in the range of 1.45 or more and 1.70 or less. It was found that mmtBumBPTzn is a material with a low refractive index. Also, for Li-6mq, the ordinary-ray refractive index is 1.67 or less throughout the blue light emission region (455 nm or more and 465 nm or less) and is in the range of 1.45 or more and 1.70 or less. The ordinary-ray refractive index at 633 nm is also 1.61 and is in the range of 1.40 or more and 1.65 or less. It was found that Li-6mq is a material with a low refractive index.

[0299] From this, it can be seen that the light-emitting device 1 is a light-emitting device in which the ordinary-ray refractive indices of both the hole transport layer 112 and the electron transport layer 114 are in the range of 1.50 or more and less than 1.75 throughout the blue light emission region (455 nm or more and 465 nm or less), and in the range of 1.45 or more and less than 1.70 at 633 nm.

[0300]

Table 2

[0301] The work of sealing the above light-emitting device and the comparative light-emitting device with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device is not exposed to the atmosphere (applying a UV-curable sealing material around the element, irradiating only the sealing material with UV so as not to irradiate the light-emitting device, heat-treating at 80 °C for 1 hour under atmospheric pressure) was performed, and then the initial characteristics of these light-emitting devices were measured.

[0302] The luminance-current density characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3 are shown in Fig. 14, the luminance-voltage characteristics are shown in Fig. 15, the current efficiency-luminance characteristics are shown in Fig. 16, the current density-voltage characteristics are shown in Fig. 17, the blue index-luminance characteristics are shown in Fig. 18, and the emission spectrum is shown in Fig. 19. Also, the main characteristics of Light-Emitting Device 1 and Comparative Light-Emitting Devices 1 to 3 near 1000 cd / m 2 are shown in Table 3. Note that a spectro-radiometer (Topcon Corporation, SR-UL1R) was used for the measurement of luminance, CIE chromaticity, and emission spectrum, and the measurement was performed at room temperature.

[0303] Note that the blue index (BI) is a value obtained by further dividing the current efficiency (cd / A) by the y chromaticity, and is one of the indexes representing the emission characteristics of blue light. Blue light tends to have higher color purity as the y chromaticity is smaller. Blue light with high color purity can express a wide range of blue even with a small luminance component, and by using blue light with high color purity, the required luminance for expressing blue decreases, resulting in an effect of reducing power consumption. Therefore, BI considering the y chromaticity, which is one of the indexes of blue purity, is preferably used as a means for expressing the efficiency of blue light, and it can be said that the higher the BI of a light-emitting device, the better the efficiency as a blue light-emitting device used in a display.

[0304]

Table 3

[0305] From FIGS. 14 to 19 and Table 3, it was found that the light-emitting device 1 using the low refractive index layer of one embodiment of the present invention in both the hole transport region 120 and the electron transport region 121 is an EL device having good current efficiency and BI while showing almost the same emission spectrum as the comparative light-emitting devices 1 and 2 in which the low refractive index layer is provided only in either the hole transport region 120 or the electron transport region 121 and the comparative light-emitting device 3 having no low refractive index region.

[0306] Also, the blue index (BI) near 1000 cd / m 2 of the light-emitting device 1 is very high at 180 (cd / A / y) or more, and the light-emitting device 1 can be said to be a light-emitting device having particularly good BI. Therefore, one embodiment of the present invention is suitable for a light-emitting device used in a display.

Example

[0307] In this example, the light-emitting device 10 which is the light-emitting device described in the embodiment and the comparative light-emitting devices 10 to 12 will be described. The structural formulas of the organic compounds used in this example are shown below.

[0308]

Chemical formula

[0309] (Method for manufacturing the light-emitting device 10) First, on a glass substrate, as a reflective electrode, silver (Ag) was formed by sputtering to a film thickness of 100 nm, and then indium tin oxide (ITSO) containing silicon oxide was formed by sputtering as a transparent electrode to a film thickness of 10 nm to form the anode 101. The electrode area was 4 mm 2 (2 mm × 2 mm).

[0310] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200° C. for 1 hour, and then UV ozone treatment was performed for 370 seconds.

[0311] Subsequently, the substrate was introduced into a vacuum evaporation apparatus whose interior had been evacuated to about 10 -4 Pa, and in the heating chamber of the vacuum evaporation apparatus, vacuum baking was carried out at 170 °C for 30 minutes. After that, the substrate was allowed to cool for about 30 minutes.

[0312] Next, the substrate with the anode 101 formed thereon was fixed to a substrate holder provided in the vacuum evaporation apparatus such that the surface on which the anode 101 was formed faced downward. Onto the anode 101, N,N-bis(4-cyclohexylphenyl)-9,9,-dimethyl-9H-fluorene-2-amine (abbreviation: dchPAF) represented by the above structural formula (xi) and an electron acceptor material (OCHD-001) were co-evaporated at 10 nm so that the weight ratio was 1:0.1 (= dchPAF:OCHD-001) to form a hole injection layer 111.

[0313] Onto the hole injection layer 111, dchPAF was evaporated at 125 nm to form a hole transport layer 112.

[0314] Subsequently, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (xii) was evaporated to a thickness of 10 nm onto the hole transport layer 112 to form an electron blocking layer.

[0315] Thereafter, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (xiii) and 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (iv) were co-evaporated at 20 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113.

[0316] Thereafter, 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm) represented by the above structural formula (xiv) was vapor-deposited to a thickness of 10 nm to form a hole-blocking layer. Then, 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumBPTzn) represented by the above structural formula (vi) and lithium 6-methyl-8-quinolinolate (abbreviation: Li-6mq) represented by the above structural formula (vii) were co-vapor-deposited in a weight ratio of 1:1 (= mmtBumBPTzn:Li-6mq) to a thickness of 20 nm to form an electron transport layer 114.

[0317] After the formation of the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form an electron injection layer 115. Finally, silver (Ag) and magnesium (Mg) were co-vapor-deposited in a volume ratio of 1:0.1 to a thickness of 15 nm to form a cathode 102, thereby fabricating a light-emitting device 10. Note that the cathode 102 is a semi-transmissive / semi-reflective electrode having a function of reflecting light and a function of transmitting light, and the light-emitting device of this example is a top-emission type device that extracts light from the cathode 102. Further, 1,3,5-tri(dibenzothiophen-4-yl)-benzene (abbreviation: DBT3P-II) represented by the above structural formula (viii) was vapor-deposited to a thickness of 70 nm on the cathode 102 to improve the extraction efficiency.

[0318] (Method for fabricating comparative light-emitting device 10) The comparative light-emitting device 10 was fabricated in the same manner as the light-emitting device 10, except that dchPAF in the light-emitting device 10 was changed to N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF) represented by the above structural formula (ix), and the film thickness of the hole transport layer was set to 115 nm.

[0319] (Method for fabricating comparative light-emitting device 11) The comparative light-emitting device 11 was fabricated in the same manner as the light-emitting device 10, except that mmtBumBPTzn in the electron transport layer of the light-emitting device 10 was changed to 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn) represented by the above structural formula (vx), Li-6mq was changed to lithium 8-quinolinolate (abbreviation: Liq) represented by the above structural formula (x), and the film thickness of the hole transport layer was set to 130 nm.

[0320] (Fabrication method of the comparative light-emitting device 12) The comparative light-emitting device 12 was fabricated in the same manner as the light-emitting device 10, except that dchPAF in the hole transport layer of the light-emitting device 1 was changed to PCBBiF, the film thickness thereof was set to 115 nm, mmtBumBPTzn in the electron transport layer was changed to mPn-mDMePyPTzn, and Li-6mq was changed to Liq.

[0321] The device structures of the light-emitting device 10 and the comparative light-emitting devices 10 to 12 are summarized in the following table.

[0322]

Table 4

[0323] In addition, the refractive indices of dchPAF and PCBBiF are shown in Fig. 31, the refractive indices of mmtBumBPTzn, mPn-mDMePyPTzn, Li-6mq and Liq are shown in Fig. 21, and the refractive index at 456 nm is shown in the following table. The measurement was performed using a spectroscopic ellipsometer (M-2000U manufactured by J. A. Woolam Japan Co., Ltd.). As the measurement sample, a film formed by vacuum deposition of about 50 nm of each layer material on a quartz substrate was used. In the figures, the refractive index of the ordinary ray n Ordinary and the refractive index of the extraordinary ray n Extra-ordinary are described.

[0324] From the figures, it was found that dchPAF has a normal light refractive index of 1.71 throughout the blue light emission region (455 nm or more and 465 nm or less), within the range of 1.50 or more and 1.75 or less, and also has a normal light refractive index of 1.64 at 633 nm, within the range of 1.45 or more and 1.70 or less. Thus, dchPAF is a material with a low refractive index. Also, mmtBumBPTzn has a normal light refractive index of 1.68 throughout the blue light emission region (455 nm or more and 465 nm or less), within the range of 1.50 or more and 1.75 or less. Its normal light refractive index at 633 nm is also 1.64, within the range of 1.45 or more and 1.70 or less. So, mmtBumBPTzn is a material with a low refractive index. Further, Li-6mq has a normal light refractive index of 1.67 or less throughout the blue light emission region (455 nm or more and 465 nm or less), within the range of 1.45 or more and 1.70 or less. Its normal light refractive index at 633 nm is 1.61, within the range of 1.40 or more and 1.65 or less. Hence, Li-6mq is a material with a low refractive index.

[0325] From this, it can be seen that the light-emitting device 10 is a light-emitting device according to one aspect of the present invention, where the normal light refractive indices of both the hole transport layer 112 and the electron transport layer 114 are in the range of 1.50 or more and less than 1.75 throughout the blue light emission region (455 nm or more and 465 nm or less), and in the range of 1.45 or more and less than 1.70 at 633 nm.

[0326]

Table 5

[0327] After performing the operation of sealing the above-mentioned light-emitting device and the comparative light-emitting device in a glove box under a nitrogen atmosphere with a glass substrate so that the light-emitting device is not exposed to the atmosphere (applying a UV curable sealing material around the element, irradiating only the sealing material with UV without irradiating the light-emitting device, and heat-treating at 80 °C for 1 hour under atmospheric pressure), the initial characteristics of these light-emitting devices were measured.

[0328] The luminance-current density characteristics of the light-emitting device 10 and the comparative light-emitting devices 10 to 12, the current efficiency-luminance characteristics in FIG. 26, the luminance-voltage characteristics in FIG. 27, the current-voltage characteristics in FIG. 28, the blue index-luminance characteristics in FIG. 29, and the emission spectrum are shown in FIG. 30. Also, the main characteristics of the light-emitting device 10 and the comparative light-emitting devices 10 to 12 near 1000 cd / m 2 are shown in Table 6. For the measurement of luminance, CIE chromaticity, and emission spectrum, a spectro-radiometer (Topcon Corporation, SR-UL1R) was used and the measurement was performed at room temperature.

[0329] Note that the blue index (BI) is a value obtained by further dividing the current efficiency (cd / A) by the y chromaticity, and is one of the indexes representing the emission characteristics of blue light. In blue light emission, the smaller the y chromaticity, the higher the color purity tends to be. Blue light emission with high color purity can represent a wide range of blue even with a small luminance component, and by using blue light emission with high color purity, the required luminance for representing blue decreases, resulting in an effect of reducing power consumption. Therefore, BI considering the y chromaticity, which is one of the indexes of blue purity, is preferably used as a means for representing the efficiency of blue light emission, and it can be said that the higher the BI of the light-emitting device, the better the efficiency as a blue light-emitting device used in the display.

[0330]

Table 6

[0331] From FIGS. 25 to 30 and Table 6, it was found that the light-emitting device 10 using the low refractive index layer of one aspect of the present invention in both the hole transport region 120 and the electron transport region 121 is an EL device having good current efficiency and BI while showing almost the same emission spectrum as the comparative light-emitting devices 10 and 11 in which the low refractive index layer is provided only in either the hole transport region 120 or the electron transport region 121, and the comparative light-emitting device 12 having no low refractive index region.

[0332] Also, 1000 cd / m of the light-emitting device 10 2The blue index (BI) in the vicinity is extremely high at 183 (cd / A / y) or more, and the light-emitting device 10 can be said to be a light-emitting device with particularly good BI. Therefore, one aspect of the present invention is suitable for a light-emitting device used in a display.

[0333] <<Reference Synthesis Example 1>> In this synthesis example, the synthesis method of N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: mmtBumTPoFBi-02) used in Example 1 will be described. The structure of mmtBumTPoFBi-02 is shown below.

[0334] [Chemical formula]

[0335] [Step 1: Synthesis of 3-bromo-3',5,5'-tri-tert-butylbiphenyl] Into a three-necked flask, 37.2 g (128 mmol) of 1,3-dibromo-5-tert-butylbenzene, 20.0 g (85 mmol) of 3,5-di-tert-butylphenylboronic acid, 35.0 g (255 mmol) of potassium carbonate, 570 mL of toluene, 170 mL of ethanol, and 130 mL of tap water were added. After degassing under reduced pressure, the inside of the flask was purged with nitrogen, 382 mg (1.7 mmol) of palladium acetate and 901 mg (3.4 mmol) of triphenylphosphine were added, and the mixture was heated at 40 °C for about 5 hours. Then, it was returned to room temperature, and the organic layer and the aqueous layer were separated. Magnesium sulfate was added to this organic layer to remove moisture and concentrated. The obtained solution was purified by silica gel column chromatography to obtain 21.5 g of a colorless oily substance as the target product, with a yield of 63%. The synthesis scheme of Step 1 is shown in the following formula.

[0336] [Chemical formula]

[0337] <Step 2: Synthesis of 2-(3’,5,5’-Tri-tert-butyl[1,1’-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane> Into a three-necked flask, add 15.0 g (38 mmol) of 3-bromo-3’,5,5’-tri-tert-butylbiphenyl obtained in Step 1, 10.5 g (41 mmol) of 4,4,4’,4’,5,5,5’,5-octamethyl-2,2’-bi-1,3,2-dioxaborolane, 11.0 g (113 mmol) of potassium acetate, and 125 mL of N,N-dimethylformamide. After degassing under reduced pressure, replace the inside of the flask with nitrogen, add 1.5 g (1.9 mmol) of [1,1’-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and heat at about 100 °C for about 3 hours. Then, return to room temperature, separate the organic layer and the aqueous layer, and extract with ethyl acetate. Add magnesium sulfate to this extraction solution to remove moisture and concentrate. Purify the toluene solution of the obtained mixture by silica gel column chromatography, concentrate the obtained solution, and obtain a concentrated toluene solution. Add ethanol to this toluene solution and concentrate under reduced pressure to obtain an ethanol suspension. Filter the precipitate at about 20 °C, and dry the obtained solid under reduced pressure at about 80 °C to obtain 13.6 g of the target white solid with a yield of 81%. The synthesis scheme of Step 2 is shown in the following formula.

[0338]

Chemical formula

[0339] <Step 3: Synthesis of 3-bromo-3’’,5,5’,5’’-tetra-tert-butyl-1,1’:3’,1’’-terphenyl> Into a three-necked flask, 5.0 g (11.1 mmol) of 2-(3’,5,5’-tri-tert-butyl[1,1’-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 4.8 g (16.7 mmol) of 1,3-dibromo-5-tert-butylbenzene, 4.6 g (33.3 mmol) of potassium carbonate, 56 mL of toluene, 22 mL of ethanol, and 17 mL of tap water were added. After degassing under reduced pressure, the inside of the flask was purged with nitrogen. Then, 50 mg (0.22 mmol) of palladium acetate and 116 mg (0.44 mmol) of triphenylphosphine were added, and the mixture was heated at 80 °C for about 10 hours. After that, the mixture was returned to room temperature, and the organic layer and the aqueous layer were separated. Magnesium sulfate was added to this solution to remove water, and the solution was concentrated. The obtained hexane solution was purified by silica gel column chromatography to obtain 3.0 g of the target white solid with a yield of 51.0%. The synthesis scheme of 3-bromo-3’’,5,5’,5’’-tetra-tert-butyl-1,1’:3’,1’’-terphenyl in Step 3 is shown by the following formula.

[0340] [Chemical formula]

[0341] <Step 4: Synthesis of mmtBumTPoFBi-02> Into a three-necked flask, add 5.8 g (10.9 mmol) of 3-bromo-3’’,5,5’,5’’-tetra-tert-butyl-1,1’:3’,1’’-terphenyl obtained in Step 3, 3.9 g (10.9 mmol) of N-(1,1’-biphenyl-4-yl)-N-phenyl-9,9-dimethyl-9H-fluorene-2-amine, 3.1 g (32.7 mmol) of sodium tert-butoxide, and 55 mL of toluene. After degassing under reduced pressure, replace the atmosphere in the flask with nitrogen. Then add 64 mg (0.11 mmol) of bis(dibenzylideneacetone)palladium(0) and 132 mg (0.65 mmol) of tri-tert-butylphosphine, and heat at 80 °C for about 2 hours. Then, return the temperature of the flask to about 60 °C, add about 1 mL of water, filter the precipitated solid, and wash it with toluene. Concentrate the filtrate, and purify the obtained toluene solution by silica gel column chromatography. Concentrate the obtained solution to obtain a concentrated toluene solution. Add ethanol to this toluene solution and concentrate under reduced pressure to obtain an ethanol suspension. Filter the precipitate at about 20 °C, and dry the obtained solid under reduced pressure at about 80 °C to obtain 8.1 g of the target white solid with a yield of 91%. The synthetic scheme of mmtBumTPoFBi-02 is shown in the following formula.

[0342]

Chemical formula

[0343] In addition, the analysis results of the white solid obtained above by nuclear magnetic resonance spectroscopy ( 1 1H-NMR) are shown below. From this, it was found that mmtBumTPoFBi-02 could be synthesized.

[0344] 1 1H-NMR. δ(CDCl 3): 7.56 (d, 1H, J = 7.4 Hz), 7.50 (dd, 1H, J = 1.7 Hz), 7.33 - 7.46 (m, 11H), 7.27 - 7.29 (m, 2H), 7.22 (dd, 1H, J = 2.3 Hz), 7.15 (d, 1H, J = 6.9 Hz), 6.98 - 7.07 (m, 7H), 6.93 (s, 1H), 6.84 (d, 1H, J = 6.3 Hz), 1.38 (s, 9H), 1.37 (s, 18H), 1.31 (s, 6H), 1.20 (s, 9H).

[0345] In addition, Fig. 22 shows the results of measuring the refractive index of mmtBumTPoFBi - 02 using a spectroscopic ellipsometer (M - 2000U manufactured by J. A. Woollam Japan Co., Ltd.). For the measurement, a film formed by vacuum deposition of about 50 nm of the material of each layer on a quartz substrate was used. In the figure, the refractive index of the ordinary ray n Ordinary and the refractive index of the extraordinary ray n Extra - ordinary are described.

[0346] From this figure, it was found that mmtBumTPoFBi - 02 has an ordinary - light refractive index in the range of 1.69 to 1.70 and 1.50 or more and 1.75 or less throughout the blue - light emission region (455 nm or more and 465 nm or less), and also the ordinary - light refractive index at 633 nm is 1.64 and in the range of 1.45 or more and 1.70 or less, indicating that it is a material with a low refractive index.

[0347] <<Reference Synthesis Example 2>> In this synthesis example, the synthesis method of 2 - {(3’,5’ - di - tert - butyl) - 1,1’ - biphenyl - 3 - yl} - 4,6 - diphenyl - 1,3,5 - triazine (abbreviation: mmtBumBPTzn) used in Example 1 will be described. The structure of mmtBumBPTzn is shown below.

[0348] [Chemical formula]

[0349] <Step 1: Synthesis of 3 - bromo - 3’,5’ - di - tert - butylbiphenyl> To a three-necked flask, 1.0 g (4.3 mmol) of 3,5-di-t-butylphenylboronic acid, 1.5 g (5.2 mmol) of 1-bromo-3-iodobenzene, 4.5 mL of 2 mol / L aqueous potassium carbonate solution, 20 mL of toluene, and 3 mL of ethanol were added, and the mixture was degassed by stirring under reduced pressure. Further, 52 mg (0.17 mmol) of tris(2-methylphenyl)phosphine and 10 mg (0.043 mmol) of palladium(II) acetate were added thereto, and the reaction was carried out at 80 °C for 14 hours under a nitrogen atmosphere. After completion of the reaction, extraction with toluene was performed, and the obtained organic layer was dried using magnesium sulfate. This mixture was filtered naturally, and the obtained filtrate was purified by silica gel column chromatography (developing solvent: hexane) to obtain 1.0 g of the target white solid (yield: 68%). The synthesis scheme of Step 1 is shown below.

[0350] [Chemical formula]

[0351] [Step 2: Synthesis of 2-(3’,5’-di-tert-butylbiphenyl-3-yl)-4,4,5,5,-tetramethyl-1,3,2-dioxaborolane] To a three-necked flask, 1.0 g (2.9 mmol) of 3-bromo-3',5'-di-tert-butylbiphenyl, 0.96 g (3.8 mmol) of bis(pinacolato)diboron, 0.94 g (9.6 mmol) of potassium acetate, and 30 mL of 1,4-dioxane were added, and the mixture was degassed by stirring under reduced pressure. Further, 0.12 g (0.30 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl and 0.12 g (0.15 mmol) of [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct were added thereto. The reaction was carried out at 110 °C for 24 hours under a nitrogen atmosphere. After completion of the reaction, extraction with toluene was performed, and the obtained organic layer was dried over magnesium sulfate. The mixture was filtered naturally. The obtained filtrate was purified by silica gel column chromatography (developing solvent: toluene) to obtain 0.89 g of the target yellow oil (yield: 78%). The synthesis scheme of Step 2 is shown below.

[0352] [Chemical formula]

[0353] <Step 3: Synthesis of mmtBumBPTzn> Into a three-necked flask, 1.5 g (5.6 mmol) of 4,6-diphenyl-2-chloro-1,3,5-triazine, 2.4 g (6.2 mmol) of 2-(3’,5’-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 2.4 g (11 mmol) of tripotassium phosphate, 10 mL of water, 28 mL of toluene, and 10 mL of 1,4-dioxane were added, and the mixture was degassed by stirring under reduced pressure. Further, 13 mg (0.056 mmol) of palladium(II) acetate and 34 mg (0.11 mmol) of tris(2-methylphenyl)phosphine were added thereto, and the mixture was heated to reflux for 14 hours under a nitrogen atmosphere to effect reaction. After completion of the reaction, extraction was carried out with ethyl acetate, and water in the obtained organic layer was removed with magnesium sulfate. The filtrate obtained by natural filtration of this mixture was purified by silica gel column chromatography (the developing solvent was changed from chloroform:hexane = 1:5 to 1:3), and then recrystallized from hexane to obtain 2.0 g of the target white solid (yield: 51%). The synthesis scheme of Step 3 is shown in the following formula.

[0354]

Chemical formula

[0355] 2.0 g of the obtained white solid was sublimation-purified by the train sublimation method by heating the solid under an argon gas stream at a pressure of 3.4 Pa and 220 °C. After sublimation purification, 1.8 g of the target white solid was obtained at a recovery rate of 80%.

[0356] In addition, the analysis results of the white solid obtained in Step 3 by nuclear magnetic resonance spectroscopy ( 1 1H-NMR) are shown below. From these results, it was found that mmtBumBPTzn was obtained in this synthesis example.

[0357] H 1 1H NMR (CDCl3, 300 MHz): δ = 1.44 (s, 18H), 7.51 - 7.68 (m, 10H), 7.83 (d, 1H), 8.73 - 8.81 (m, 5H), 9.01 (s, 1H).

[0358] Also, Fig. 23 shows the results of measuring the refractive index of mmtBumBPTzn using a spectroscopic ellipsometer (M-2000U manufactured by J. A. Woollam Japan Co., Ltd.). For the measurement, a film formed by vacuum deposition of about 50 nm of the material of each layer on a quartz substrate was used. In the figure, the refractive index of the ordinary ray n Ordinary and the refractive index of the extraordinary ray n Extra-ordinary are described.

[0359] From this figure, it can be seen that for mmtBumBPTzn, the refractive index of the ordinary ray is 1.68 throughout the blue light emission region (455 nm or more and 465 nm or less), and is in the range of 1.50 or more and 1.75 or less. Also, the refractive index of the ordinary ray at 633 nm is 1.64 and is in the range of 1.45 or more and 1.70 or less, indicating that mmtBumBPTzn is a material with a low refractive index.

[0360] <<Reference Synthesis Example 3>> In this example, the synthesis method of lithium 6-methyl-8-quinolinolate (abbreviation: Li-6mq) used in Example 1 will be described. The structural formula of Li-6mq is shown.

[0361] [Chemical formula]

[0362] 2.0 g (12.6 mmol) of 8-hydroxy-6-methylquinoline and 130 mL of dehydrated tetrahydrofuran (abbreviation: THF) were placed in a three-necked flask and stirred. To this solution, 10.1 mL (10.1 mmol) of a 1 M THF solution of lithium tert-butoxide (abbreviation: tBuOLi) was added, and the mixture was stirred at room temperature for 47 hours. The reaction solution was concentrated to obtain a yellow solid. Acetonitrile was added to this solid, ultrasonic irradiation was performed, and filtration was carried out to obtain a pale yellow solid. This washing operation was performed twice. As the filtrate, 1.6 g (yield 95%) of a pale yellow solid of Li-6mq was obtained. The present synthesis scheme is shown below.

[0363] [Chemical formula]

[0364] Next, the absorption spectrum and emission spectrum of the dehydrated acetone solution of Li-6mq were measured. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550 type manufactured by JASCO Corporation), and the spectrum obtained by putting only dehydrated acetone in a quartz cell was subtracted. Also, a fluorometer (FP-8600 manufactured by JASCO Corporation) was used to measure the emission spectrum.

[0365] As a result, the dehydrated acetone solution of Li-6mq showed an absorption peak at 390 nm, and the peak of the emission wavelength was 540 nm (excitation wavelength 385 nm).

[0366] Also, Fig. 24 shows the results of measuring the refractive index of Li-6mq using a spectroscopic ellipsometer (M-2000U manufactured by J. A. Woollam Japan Co., Ltd.). For the measurement, a film formed by vacuum deposition of about 50 nm of the material for each layer on a quartz substrate was used. In the figure, the refractive index of the ordinary ray n Ordinary and the refractive index of the extraordinary ray n Extra-ordinary are described.

[0367] From this figure, it was found that Li-6mq is a material with a low refractive index.

Explanation of Signs

[0368] 101: Anode, 102: Cathode, 103: EL layer, 111: Hole injection 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: Electron relay layer, 119: Electron injection buffer layer, 120: Hole transport region, 121: Electron transport region, 400: Substrate, 401: Anode, 403: EL layer, 404: Cathode, 405: Sealing material, 406: Sealing material, 407: Encapsulation substrate, 412: Pad, 420: IC chip, 601: Driving circuit section (source line driving circuit), 602: Pixel section, 603: Driving circuit section (gate line driving circuit), 604: Encapsulation substrate, 605: Sealing material, 607: Space, 608: Wiring, 609: FPC (Flexible Printed Circuit), 610: Element substrate, 611: Switching FET, 612: Current control FET, 613: Anode, 614: Insulator, 616: EL layer, 617: Cathode, 618: Light-emitting device, 951: Substrate, 952: Electrode, 953: Insulating layer, 954: Partition layer, 955: EL layer, 956: Electrode, 1001 Substrate, 1002 Underlying insulating film, 1003 Gate insulating film, 1006 Gate electrode, 1007 Gate electrode, 1008 Gate electrode, 1020 First interlayer insulating film, 1021 Second interlayer insulating film, 1022 Electrode, 1024W Anode, 1024R Anode, 1024G Anode, 1024B Anode, 1025 Partition, 1028 EL layer, 1029 Cathode, 1031 Encapsulation substrate, 1032 Sealing material, 1033 Transparent base material, 1034R Red coloring layer, 1034G Green coloring layer, 1034B Blue coloring layer, 1035 Black matrix, 1036 Overcoat layer, 1037 Third interlayer insulating film, 1040 Pixel section, 1041 Driving circuit section, 1042Peripheral part, 2001: Housing, 2002: Light source, 2100: Robot, 2110: Arithmetic unit, 2101: Illuminance sensor, 2102: Microphone, 2103: Upper camera, 2104: Speaker, 2105: Display, 2106: Lower camera, 2107: Obstacle sensor, 2108: Moving mechanism, 3001: Lighting device, 5000: Housing, 5001: Display unit, 5002: Second display unit, 5003: Speaker, 5004: LED lamp, 5006: Connection terminal, 5007: Sensor, 5008: Microphone, 5012: Support part, 5013: Earphone, 5100: Cleaning robot, 5101: Display, 5102: Camera, 5103: Brush, 5104: Operation button, 5150: Portable information terminal, 5151: Housing, 5152: Display area, 5153: Bending part, 5120: Dust, 5200: Display area, 5201: Display area, 5202: Display area, 5203: Display area, 7101: Housing, 7103: Display part, 7105: Stand, 7107: Display part, 7109: Operation key, 7110: Remote control operation unit, 7201: Main body, 7202: Housing, 7203: Display part, 7204: Keyboard, 7205: External connection port, 7206: Pointing device, 7210: Display part, 7401: Housing, 7402: Display part, 7403: Operation button, 7404: External connection port, 7405: Speaker, 7406: Microphone, 9310: Portable information terminal, 9311: Display panel, 9313: Hinge, 9315: Housing

Claims

1. An anode, a cathode, a first layer, a second layer, and a third layer located between the anode and the cathode, wherein the first layer is located between the anode and the second layer, the third layer is located between the second layer and the cathode, the first layer contains an organic compound having hole transporting properties, the third layer contains an organic compound having electron transporting properties, the organic compound having hole transporting properties is a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less, A light-emitting device in which the ordinary light refractive index of each of the organic compound having hole transporting properties and the organic compound having electron transporting properties in light having a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less.

2. An anode, a cathode, a first layer, a second layer, and a third layer located between the anode and the cathode, wherein the first layer is located between the anode and the second layer, the third layer is located between the second layer and the cathode, the first layer contains an organic compound having hole transporting properties, the third layer contains an organic compound having electron transporting properties, the organic compound having electron transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming a bond with a plurality of sp3 hybrid orbitals, and the total number of carbon atoms forming a bond with the sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron transporting properties, A light-emitting device in which the ordinary light refractive index of each of the organic compound having hole transporting properties and the organic compound having electron transporting properties in light having a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less.

3. An anode, a cathode, a first layer, a second layer, and a third layer located between the anode and the cathode, wherein the first layer is located between the anode and the second layer, the third layer is located between the second layer and the cathode, the first layer contains an organic compound having hole transporting properties, the third layer contains an organic compound having electron transporting properties, the organic compound having hole transporting properties is a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less, The organic compound having electron transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and hydrocarbon groups that form bonds with a plurality of sp3 hybrid orbitals. The total number of carbons that form bonds with the sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbons in the molecule of the organic compound having electron transporting properties. An organic light emitting device in which the ordinary light refractive index of each of the organic compound having hole transporting properties and the organic compound having electron transporting properties at a wavelength of 455 nm or more and 465 nm or less is 1.5 or more and 1.75 or less. Claim 4 An anode, A cathode, A first layer, a second layer, and a third layer located between the anode and the cathode, The first layer is located between the anode and the second layer, The third layer is located between the second layer and the cathode, The first layer contains an organic compound having hole transporting properties, The third layer contains an organic compound having electron transporting properties, The organic compound having hole transporting properties is a monoamine compound, and the ratio of the carbon atoms that form bonds with sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound is 23% or more and 55% or less. An organic light emitting device in which the refractive index of each of the organic compound having hole transporting properties and the organic compound having electron transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less. Claim 5 An anode, A cathode, A first layer, a second layer, and a third layer located between the anode and the cathode, The first layer is located between the anode and the second layer, The third layer is located between the second layer and the cathode, The first layer contains an organic compound having hole transporting properties, The third layer contains an organic compound having electron transporting properties, The organic compound having electron transporting properties has at least one 6-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and hydrocarbon groups that form bonds with a plurality of sp3 hybrid orbitals. The total number of carbons that form bonds with the sp3 hybrid orbitals is 10% or more and 60% or less of the total number of carbons in the molecule of the organic compound having electron transporting properties. An organic light emitting device in which the refractive index of each of the organic compound having hole transporting properties and the organic compound having electron transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

6. An anode, a cathode, a first layer, a second layer, and a third layer positioned between the anode and the cathode, the first layer being positioned between the anode and the second layer, the third layer being positioned between the second layer and the cathode, the first layer containing an organic compound having hole transporting properties, the third layer containing an organic compound having electron transporting properties, the organic compound having hole transporting properties being a monoamine compound, and the ratio of carbon atoms bonded by sp3 hybrid orbitals to the total number of carbon atoms in the monoamine compound being 23% or more and 55% or less, the organic compound having electron transporting properties having at least one six-membered heteroaromatic ring containing nitrogen, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds with a plurality of sp3 hybrid orbitals, and the total number of carbon atoms forming bonds with the sp3 hybrid orbitals being 10% or more and 60% or less of the total number of carbon atoms in the molecule of the organic compound having electron transporting properties, A light-emitting device in which the refractive index of each of the organic compound having hole transporting properties and the organic compound having electron transporting properties with respect to light having a wavelength of 633 nm is 1.45 or more and 1.70 or less.

7. In any one of Claims 1 to 6, A light-emitting device in which the first layer is a hole transport layer and / or a hole injection layer.

8. In any one of Claims 1 to 7, A light-emitting device in which the third layer is an electron transport layer and / or an electron injection layer.

9. In any one of Claims 1 to 8, A light-emitting device in which one or both of the anode and the cathode have a function of reflecting all or part of the light from the light-emitting layer.

10. In any one of Claims 1 to 9, A light-emitting device in which one or both of the anode and the cathode contain a metal.

11. In any one of Claims 1 to 10, A light-emitting device in which the second layer is a light-emitting layer.

12. A light-emitting device according to any one of Claims 1 to 11, and at least one of a sensor, an operation button, a speaker, and a microphone, An electronic device having the same.

13. A light-emitting device according to any one of Claims 1 to 11, and at least one of a transistor and a substrate, A light-emitting device having the same.

14. A lighting device comprising the light-emitting device according to any one of claims 1 to 11 and a housing, and having.

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