Light emitting device, light emitting apparatus, and display apparatus

Abstract

To provide an inexpensive light emitting device having high luminous efficiency.SOLUTION: An light emitting device includes: an anode; a cathode; and an EL layer positioned between the anode and the cathode. The EL layer includes a hole transport region, a light-emitting layer, and an electron transport region. The hole transport region is positioned between the anode and the light-emitting layer. The electron transport region is positioned between the cathode and the light emitting layer. The hole transport region includes one of a sulfonic acid compound, a fluorine compound, or a metal oxide. The electron transport region includes an organic compound having an electron transport property. The organic compound having the electron transport property provides the light emitting device having an ordinary index of light refraction of greater than or equal to 1.50 and less than or equal to 1.75 with respect to light having wavelengths of greater than or equal to 455nm and less than or equal to 465nm.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

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

[0003] Since such light-emitting devices are self-luminous, when used as display pixels, they offer advantages such as higher visibility and no need for backlighting compared to liquid crystal displays, making them particularly suitable for flat panel displays. Another major advantage of displays using such light-emitting devices is that they can be fabricated to be thin and lightweight. Another feature is their extremely fast response time.

[0004] Furthermore, these light-emitting devices can emit light continuously in two dimensions, making it possible to obtain surface light emission. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs and LEDs, or linear light sources such as fluorescent lamps, making them highly useful as surface light sources for lighting applications.

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

[0006] One of the problems often cited when discussing organic EL devices is their low light extraction efficiency. In particular, attenuation due to reflection caused by differences in the refractive index of adjacent layers is a major factor in reducing the efficiency of light-emitting devices. To reduce this effect, a structure has been proposed in which a layer made of a low-refractive-index material is formed inside the EL layer (see, for example, Non-Patent Document 1).

[0007] In addition, commercialized organic EL devices are often manufactured using the vapor deposition method, but this method is costly in terms of material efficiency and maintaining the manufacturing atmosphere, so it is expected that the application of wet film formation will enable cheaper manufacturing. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] US Patent Application Publication No. 2020 / 0176692 Summary of the Invention [Problem to be solved by the invention]

[0009] An object of one embodiment of the present invention is to provide a light-emitting device with high emission efficiency. Alternatively, an object of one embodiment of the present invention is to provide any one of a light-emitting device, a light-emitting device, an electronic device, a display device, and an electronic device with low power consumption. Another object of one embodiment of the present invention is to provide an inexpensive light-emitting device. Another object of one embodiment of the present invention is to provide an inexpensive light-emitting device with high emission efficiency.

[0010] The present invention is intended to solve any one of the above problems. [Means for solving the problem]

[0011] One aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer having a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, the hole transport region comprising a layer formed by applying and baking an ink containing a sulfonic acid compound, the electron transport region comprising an organic compound having electron transport properties, and the organic compound having electron transport properties having an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less.

[0012] Alternatively, another aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, the hole transport region comprising a layer formed by applying and baking an ink containing a sulfonic acid compound, and the electron transport region comprising an organic compound having electron transport properties, the organic compound having electron transport properties having an ordinary refractive index for light with a wavelength of 633 nm of 1.45 or more and 1.70 or less.

[0013] Alternatively, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the hole transport region has a layer formed by applying and baking a varnish containing the sulfonic acid compound and the secondary amine compound. Note that the varnish described in this specification and the like can be referred to as ink. Also, the ink described in this specification and the like can be referred to as varnish.

[0014] Alternatively, another aspect of the present invention is a light-emitting device comprising: an anode, a cathode, and an EL layer located between the anode and the cathode; the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; the hole transport region comprises one of a sulfonic acid compound, a fluorine compound, or a metal oxide; the electron transport region comprises an organic compound having electron transport properties, and the organic compound having electron transport properties has an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less.

[0015] Alternatively, another aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, the hole transport region comprising any one of a sulfonic acid compound, a fluorine compound, or a metal oxide, the electron transport region comprising an organic compound having electron transport properties, and the organic compound having electron transport properties having an ordinary refractive index for light with a wavelength of 633 nm of 1.45 or more and 1.70 or less.

[0016] Another aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, wherein when the hole transport region is measured by ToF-SIMS in a negative mode, a signal is detected at around m / z=80, and the electron transport region comprises an organic compound having electron transport properties, and the organic compound having electron transport properties has an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less.

[0017] Alternatively, another aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, the hole transport region having a signal at about m / z=80 in negative mode measurement results when measured by ToF-SIMS, and the electron transport region comprising an organic compound having electron transport properties, the organic compound having electron transport properties having an ordinary refractive index for light with a wavelength of 633 nm of 1.45 or more and 1.70 or less.

[0018] Alternatively, another aspect of the present invention is a light-emitting device having the above-described configuration, wherein the hole transport region exhibits signals detected near m / z=80 and m / z=901 in negative mode measurement results when measured by ToF-SIMS.

[0019] Alternatively, another aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, wherein a signal is detected in the hole transport region at around m / z=80 in negative mode measurement results when MS analysis is performed, and the electron transport region comprises an organic compound having electron transport properties, and the organic compound having electron transport properties has an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less.

[0020] Alternatively, another aspect of the present invention is a light-emitting device comprising an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer comprising a hole transport region, a light-emitting layer, and an electron transport region, the hole transport region being located between the anode and the light-emitting layer, and the electron transport region being located between the cathode and the light-emitting layer, the hole transport region having a signal at about m / z=80 in negative mode measurement results when subjected to MS analysis, and the electron transport region comprising an organic compound having electron transport properties, the organic compound having electron transport properties having an ordinary refractive index for light with a wavelength of 633 nm of 1.45 or more and 1.70 or less.

[0021] Alternatively, another aspect of the present invention is a light-emitting device having the above-mentioned configuration, wherein the hole transport region detects a signal in a mass range of the target ion ±2.0 to a mass number that is 241, 161, or 81 smaller than the mass number of the target ion in negative mode when MS analysis is performed.

[0022] Another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting layer contains an iridium complex.

[0023] Another embodiment of the present invention is a light-emitting device having the above structure, in which the iridium complex exhibits green phosphorescence.

[0024] Alternatively, another aspect of the present invention is a light-emitting device having the above-mentioned configuration, wherein the light-emitting layer is analyzed by ToF-SIMS, and a signal is detected around m / z=1676 in a positive mode measurement result.

[0025] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the iridium complex is an iridium complex represented by the following structural formula:

[0026] [ka]

[0027] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the organic compound having electron-transport properties includes at least one nitrogen-containing six-membered heteroaromatic ring, two benzene rings, one or more aromatic hydrocarbon rings having 6 to 14 carbon atoms, and a hydrocarbon group forming bonds through a plurality of sp3 hybridized orbitals, and the total number of carbon atoms forming bonds through the sp3 hybridized orbitals is 10% to 60% of the total number of carbon atoms in a molecule of the organic compound having electron-transport properties.

[0028] Alternatively, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the electron transport region includes an electron transport layer and an electron injection layer, the electron injection layer is provided in contact with the cathode, and the organic compound having electron transport properties is contained in the electron transport layer.

[0029] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron transport layer further contains a metal complex of an alkali metal or an alkaline earth metal.

[0030] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron transport layer is a metal complex of an alkali metal or alkaline earth metal further having a ligand including an 8-quinolinolato structure.

[0031] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the metal complex of an alkali metal or an alkaline earth metal is a metal complex of lithium.

[0032] Alternatively, another aspect of the present invention is a light-emitting device having the above-described configuration, wherein, when the electron injection layer is analyzed by ToF-SIMS, a signal is detected around m / z=587 in the measurement results in a positive mode or a negative mode.

[0033] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron injection layer contains a heteroaromatic compound.

[0034] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the heteroaromatic compound is 2-phenyl-9-[3-(9-phenyl-1,10-phenanthroline-2-yl)phenyl]-1,10-phenanthroline.

[0035] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron injection layer further contains fluorine and sodium.

[0036] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron injection layer contains barium.

[0037] Alternatively, another embodiment of the present invention is a light-emitting device including a plurality of any one of the light-emitting devices, in which the plurality of light-emitting devices include at least a light-emitting device that emits red light and a light-emitting device that emits green light, and in which the light-emitting layers of the light-emitting device that emits red light and the light-emitting device that emits green light contain iridium.

[0038] Another embodiment of the present invention is a light-emitting device having the above structure, wherein light emitted from the light-emitting device emitting red light and the light-emitting device emitting green light is phosphorescence.

[0039] Alternatively, another aspect of the present invention is a light-emitting device having the above-described configuration, wherein the plurality of light-emitting devices further includes a light-emitting device that emits blue light, and the light obtained from the light-emitting device that emits blue light is fluorescent light.

[0040] Another embodiment of the present invention is a light-emitting device including a plurality of any of the above light-emitting devices.

[0041] Another embodiment of the present invention is a display device including any one of the above light-emitting devices.

[0042] Another embodiment of the present invention is an electronic device including any of the above light-emitting devices, a sensor, an operation button, and a speaker or a microphone.

[0043] Another embodiment of the present invention is a lighting device including any of the above light-emitting devices and a housing.

[0044] In this specification, the term "light-emitting device" includes an image display device using a light-emitting device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or TCP (Tape Carrier Package), is attached to a light-emitting device, a module in which a printed wiring board is provided at the end of the TCP, or a module in which an IC (integrated circuit) is directly mounted on a light-emitting device using a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may include a light-emitting device. [Effects of the Invention]

[0045] According to one embodiment of the present invention, a light-emitting device with high emission efficiency or a light-emitting device, a light-emitting apparatus, an electronic device, a display device, or an electronic device with low power consumption can be provided.

[0046] Another embodiment of the present invention provides a novel organometallic complex (metal complex). Alternatively, another embodiment of the present invention provides a metal complex applicable to a light-emitting device with a low driving voltage. Alternatively, another embodiment of the present invention provides a metal complex applicable to a light-emitting device having an electron transport layer with a low refractive index and a low driving voltage.

[0047] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract other effects from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0048] [Figure 1] 1A, 1B, 1C and 1D are schematic diagrams of light emitting devices. [Figure 2] 2A and 2B are diagrams showing an active matrix light emitting device. [Figure 3] 3A and 3B are diagrams showing an active matrix light emitting device. [Figure 4] FIG. 4 is a diagram showing an active matrix light emitting device. [Figure 5] 5A and 5B are diagrams showing a passive matrix light emitting device. [Figure 6] 6A and 6B are diagrams illustrating a lighting device. [Figure 7] 7A, 7B1, 7B2 and 7C are diagrams showing electronic devices. [Figure 8] 8A, 8B and 8C are diagrams showing electronic devices. [Figure 9] FIG. 9 is a diagram showing a lighting device. [Figure 10] FIG. 10 is a diagram showing a lighting device. [Figure 11] FIG. 11 is a diagram showing an in-vehicle display device and a lighting device. [Figure 12] 12A and 12B are diagrams illustrating electronic devices. [Figure 13] 13A, 13B and 13C are diagrams showing electronic devices. [Figure 14] FIG. 14 shows the absorption and emission spectra of Li-6mq in a dehydrated acetone solution. [Figure 15] FIG. 15 shows data obtained by measuring the refractive index of mmtBumBPTzn. [Figure 16] 16A to 16D are diagrams showing an example of a method for manufacturing a light-emitting device. [Figure 17] FIG. 17 is a conceptual diagram illustrating a droplet ejection device. [Figure 18] Figure 18 is the MS spectrum of NSO-2. [Figure 19] FIG. 19 shows ESR spectra of a mixed thin film of NSO-2 and DPA, a single film of NSO-2, and a single film of DPA. DETAILED DESCRIPTION OF THE INVENTION

[0049] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be readily understood by those skilled in the art that various changes in form and details can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0050] (Embodiment 1) 1A shows a diagram of a light-emitting device according to one embodiment of the present invention, which includes an anode 101, a cathode 102, and an EL layer 103. The EL layer 103 includes a hole-transporting region 120, an emitting layer 113, and an electron-transporting region 121.

[0051] Although the hole transport region 120 is shown to have a hole injection layer 111 and a hole transport layer 112, and the electron transport region 121 is shown to have an electron transport layer 114 and an electron injection layer 115, either of these layers may be omitted, or other functional layers may be provided. Examples of other functional layers include a carrier block layer, an exciton block layer, and a charge generation layer.

[0052] The light-emitting layer 113 contains at least a light-emitting material, and the electron transport region 121 contains at least an organic compound having electron transport properties. The hole transport region 120 includes at least a layer formed by a wet film formation method.

[0053] The hole transport region 120 has a layer formed by depositing ink containing a material by a wet deposition method, such as an inkjet method. The hole transport region 120 is formed by laminating a single layer or multiple layers selected from layers having desired functions, such as the hole injection layer 111, the hole transport layer 112, and an electron blocking layer. Note that the structure need not be limited to a single layer having one function, and may instead include layers having multiple functions, such as a hole injection transport layer.

[0054] As the name suggests, the hole transport region 120 has the function of transporting holes between the anode 101 and the light-emitting layer 113, and therefore preferably contains a material having a skeleton with relatively high hole transportability in the hole transport region 120. Examples of skeletons with high hole transportability include π-electron-rich heteroaromatic skeletons such as an arylamine skeleton, a pyrrole skeleton, a carbazole skeleton, and a thiophene skeleton.

[0055] 1A and 1B, the hole transport region 120 includes two layers: a hole injection layer 111 and a hole transport layer 112. When layers in contact with the anode 101, such as the hole injection layer 111 and the hole injection transport layer, are formed by a wet film formation method, it is preferable that a material exhibiting acceptor properties is simultaneously contained in the skeleton having high hole transport properties. Examples of such materials exhibiting acceptor properties include sulfonic acid compounds, fluorine compounds, trifluoroacetic acid compounds, propionic acid compounds, and metal oxides.

[0056] The ink to be applied may be a polymer material, low molecular weight material, dendrimer, or the like having the desired function, either as is or dispersed or dissolved in a solvent. Alternatively, an ink containing one or more monomers of the desired polymer material may be applied, and then crosslinked, condensed, polymerized, coordinated, salt-formed, or other bonds may be formed after application by heating or irradiating with energy light. The ink may also contain organic compounds with other functions, such as surfactants or viscosity-adjusting substances.

[0057] When applying an ink containing a mixture of monomers, it is preferable to use a secondary amine and an arylsulfonic acid as the monomers.

[0058] The secondary amine can be a substituted or unsubstituted aryl group having 6 to 14 carbon atoms or a substituted or unsubstituted π-electron-rich heteroaryl group having 6 to 12 carbon atoms. Examples of aryl groups that can be used include phenyl, biphenyl, naphthyl, fluorenyl, phenanthrenyl, and anthryl groups. Phenylenol is preferred because it has good solubility and is inexpensive. Examples of heteroaryl groups that can be used include carbazole, pyrrole, thiophene, furan, and imidazole skeletons. Multiple bonds via arylamines or heteroarylamines are preferred for improved film quality, and oligomers or polymers may be used. When multiple amines are present, some of the amines may be tertiary amines, and it is preferable that the proportion of secondary amines is greater than the proportion of tertiary amines. The number of amines is preferably 1,000 or less, more preferably 10 or less, and the molecular weight is preferably 100,000 or less. Fluorine substitution is also preferred for improved compatibility with fluorine-substituted compounds.

[0059] As the secondary amine, for example, an organic compound represented by the following general formula (Gam2) is preferred, and as the tertiary amine, for example, an organic compound represented by the following general formula (Gam3) is preferred.

[0060] [ka]

[0061] However, in the above general formula (Gam2), Ar 11 ~Ar 13 At least one of the groups represents hydrogen, and the rest represent a substituted or unsubstituted aromatic ring having 6 to 14 carbon atoms; Ar 14 ~Ar 17 represents a substituted or unsubstituted aromatic ring having 6 to 14 carbon atoms. 12 and Ar 16 , Ar 14 and Ar 16 , Ar 11 and Ar 14 , Ar 14 and Ar 15 , Ar 15 and Ar17 , Ar 13 and Ar 17 may be bonded to each other to form a ring. Furthermore, p represents an integer of 0 to 1000, preferably 0 to 3. The molecular weight of the organic compound represented by general formula (Gam2) is preferably 100,000 or less. Examples of aromatic rings having 6 to 14 carbon atoms include a benzene ring, a bisbenzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, and an anthracene ring.

[0062] [ka]

[0063] However, in the above general formula (Gam3), Ar 21 ~Ar 23 represents a substituted or unsubstituted aryl group having 6 to 14 carbon atoms, and these may be bonded to each other to form a ring. 21 ~Ar 23 When has a substituent, the substituent may be a group in which a plurality of diarylamino groups or carbazolyl groups are linked together.

[0064] Specific examples of secondary amines (having an NH group) include organic compounds represented by the following structural formulae (Am2-1) to (Am2-32). The conductivity of amine compounds is improved by mixing them with sulfonic acid compounds (p-doping). Secondary amines are preferred because they can form bonds with the mixed sulfonic acid compounds through dehydration reactions, etc. When the sulfonic acid compounds or other mixed compounds are fluorides, the use of fluorides such as those represented by the following structural formulae (Am2-1), (Am2-22) to (Am2-28), and (Am2-31) improves compatibility and is therefore preferred.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] A thiophene derivative may be used instead of the secondary amine. Specific examples of the thiophene derivative include organic compounds represented by the following structural formulas (T-1) to (T-4), polythiophene, and poly(3,4-ethylenedioxythiophene) (PEDOT). The conductivity of the thiophene derivative is improved by mixing it with a sulfonic acid compound (p-doping).

[0071] [ka]

[0072] The arylsulfonic acid may contain any sulfo group, and sulfonic acid or sulfonate salts, alkoxysulfonic acids, halogenated sulfonic acids, or sulfonate anions may be used. Specifically, the sulfo group may be any of the groups described above. Multiple sulfo groups may be present. The aryl group of the arylsulfonic acid may be a substituted or unsubstituted aryl group having 6 to 16 carbon atoms. Examples of aryl groups include phenyl, biphenyl, naphthyl, fluorenyl, phenanthrenyl, anthryl, and pyrenyl groups. Naphthyl groups are preferred for their solubility and transportability in organic solvents. These arylsulfonic acids may contain multiple aryl groups. Fluorine-substituted aryl groups are preferred because they allow for deep (largely negative) adjustment of the LUMO level. They may also contain bonds via ether bonds, sulfide bonds, or amines. When multiple aryl groups are present, these bonds are preferred because they improve solubility in organic solvents. Even when alkyl groups are present as substituents, they may be bonded via ether bonds, sulfide bonds, or amines. The polymer may be substituted with a plurality of arylsulfonic acids. Examples of the polymer that can be used include polyethylene, nylon, polystyrene, and polyfluorenylene, with polystyrene and polyfluorenylene being preferred due to their good electrical conductivity.

[0073] Specific examples of arylsulfonic acid compounds include organic compounds represented by the following structural formulas (S-1) to (S-15). Polymers with sulfo groups, such as poly(4-styrenesulfonic acid) (PSS), can also be used. The use of arylsulfonic acid compounds allows them to accept electrons from electron donors with shallow HOMOs (such as amine compounds, carbazole compounds, and thiophene compounds). Mixing them with electron donors can provide hole injection and hole transport properties from electrodes. The use of fluorine compounds allows for the LUMO level to be adjusted to a deeper level (more negative energy level).

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] [ka]

[0078] For the ink containing the secondary amine and sulfonic acid, a tertiary amine is preferable because it is electrochemically and optically more stable than the secondary amine and improves hole transport properties when mixed. As the tertiary amine, for example, an organic compound represented by the following structural formula (Am3-1) to structural formula (Am3-7) is preferable. Other materials having hole transport properties may also be mixed as appropriate.

[0079] [ka]

[0080] [ka]

[0081] In addition to arylsulfonic acid compounds, cyano compounds such as tetracyanoquinodimethane compounds can also be used as electron acceptors, such as 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ) and dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile (HAT-CN6).

[0082] In addition, it is preferable that the ink containing the above-mentioned monomers contains either or both of a 3,3,3-trifluoropropyltrimethoxysilane compound and a phenyltrimethoxysilane compound, since this improves wettability when the film is formed by a wet process.

[0083] As described above, when a layer formed by a wet deposition method using an ink containing at least two monomers, an electron donor such as a secondary amine (or thiophene, etc.) and an arylsulfonic acid, is measured by ToF-SIMS or LC-MS, a signal is observed near m / z = 80 in negative mode. At the same time, signals derived from the amine monomer are hardly observed. When such analytical results are obtained for a light-emitting device, the layer is considered to function as a light-emitting device, which means that the layer possesses sufficient hole transport capability. The absence of a backbone responsible for hole transport capability while maintaining sufficient hole transport capability suggests that the monomers are bonded together to form a polymeric film. This indicates that the layer was formed by a wet deposition method. The signal at m / z = 80 is derived from the SO3 anion in the arylsulfonic acid. Furthermore, in the negative mode of MS analysis, product ions with mass numbers 241, 161, or 81 less than the target ion mass range of ±2.0 (isolation window = 4) were also observed, suggesting that one or more sulfonic groups had been removed from the target ion.

[0084] As for arylsulfonic acid compounds, sulfonic acid compounds represented by the structural formula (S-1) or (S-2) above are preferred because they contain many sulfo groups, can form three-dimensional bonds with amines, and tend to stabilize the film quality. In layers prepared using these arylsulfonic acid compounds, in addition to the signal at m / z=80 mentioned above, a signal near m / z=901 is observed in the negative mode. A signal near m / z=328 is also observed as a product ion.

[0085] Here, a method for forming the layer 786 containing a light-emitting substance by a droplet discharging method will be described with reference to Fig. 16. Fig. 16A to Fig. 16D are cross-sectional views illustrating a method for manufacturing the layer 786 containing a light-emitting substance.

[0086] First, a conductive film 772 is formed over a planarization insulating film 770, and an insulating film 730 is formed so as to cover part of the conductive film 772 (see FIG. 16A).

[0087] Next, droplets 784 are discharged from a droplet discharge device 783 onto exposed portions of the conductive film 772, which are openings in the insulating film 730, to form a layer 785 containing a composition. The droplets 784 are a composition containing a solvent, and are attached to the conductive film 772 (see FIG. 16B).

[0088] The step of discharging the droplets 784 may be performed under reduced pressure.

[0089] Next, the solvent is removed from layer 785 containing the composition, and the layer is solidified to form layer 786 containing a light-emitting material (see FIG. 16C).

[0090] The solvent may be removed by a drying step or a heating step.

[0091] Next, a conductive film 788 is formed over the layer 786 containing a light-emitting material to form a light-emitting element 782 (see FIG. 2D).

[0092] When the layer 786 containing a light-emitting material is formed by a droplet discharge method, the composition can be selectively discharged, which reduces material waste. In addition, since a lithography process for processing the shape is not required, the process can be simplified, and cost reduction can be achieved.

[0093] The droplet discharge method described above is a general term for a method having means for discharging droplets, such as a nozzle having a discharge port for discharging the composition, or a head having one or more nozzles.

[0094] Next, a droplet discharge device used in the droplet discharge method will be described with reference to Fig. 17. Fig. 17 is a conceptual diagram illustrating a droplet discharge device 1400.

[0095] The droplet discharge device 1400 has a droplet discharge means 1403. The droplet discharge means 1403 also has a head 1405, a head 1412, and a head 1416.

[0096] Head 1405, head 1412 and head 1416 are connected to control means 1407, which can be controlled by computer 1410 to draw a pre-programmed pattern.

[0097] The timing of drawing may be determined, for example, based on a marker 1411 formed on the substrate 1402. Alternatively, the reference point may be determined based on the outer edge of the substrate 1402. Here, the marker 1411 is detected by the imaging means 1404, and converted into a digital signal by the image processing means 1409. The digital signal is recognized by the computer 1410, which generates a control signal and sends it to the control means 1407.

[0098] An image sensor using a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) can be used as the imaging means 1404. Information about the pattern to be formed on the substrate 1402 is stored in a storage medium 1408, and based on this information, control signals are sent to a control means 1407, which can individually control the heads 1405, 1412, and 1416 of the droplet ejection means 1403. The material to be ejected is supplied to heads 1405, 1412, and 1416 from material supply sources 1413, 1414, and 1415 through pipes, respectively.

[0099] The interior of heads 1405, 1412, and 1416 is structured with a space filled with liquid material and nozzles as ejection ports, as indicated by dotted lines 1406. Although not shown, head 1412 has a similar internal structure to head 1405. Providing different sized nozzles for heads 1405 and 1412 allows for simultaneous drawing of different materials with different widths. A single head can eject and draw multiple types of luminescent materials, etc. To improve throughput when drawing over a large area, the same material can be ejected simultaneously from multiple nozzles. When using a large substrate, heads 1405, 1412, and 1416 can freely scan the substrate in the X, Y, and Z arrow directions shown in Figure 17, allowing for the drawing area to be freely set, enabling the same pattern to be drawn multiple times on a single substrate.

[0100] Furthermore, the step of discharging the composition may be carried out under reduced pressure. The substrate may be heated during discharging. After discharging the composition, one or both of the steps of drying and baking are carried out. Both the drying and baking steps are heat treatment steps, but they differ in purpose, temperature, and time. The drying and baking steps are carried out under normal pressure or reduced pressure, in air or in an inert atmosphere such as nitrogen, by irradiation with laser light, flash thermal annealing, or a heating furnace. The timing of this heat treatment and the number of times it is carried out are not particularly limited. In order to perform the drying and baking steps well, the temperature at that time depends on the material of the substrate and the properties of the composition.

[0101] As described above, the layer 786 containing a light-emitting substance can be manufactured using a droplet discharge apparatus.

[0102] When preparing the layer 786 containing a light-emitting material using a droplet ejection apparatus, various organic materials or organic / inorganic halogen perovskites dissolved or dispersed in a solvent can be used as a wet coating composition. Examples of organic solvents that can be used in the composition include benzene, toluene, xylene, mesitylene, tetrahydrofuran, dioxane, ethanol, methanol, n-propanol, isopropanol, n-butanol, t-butanol, acetonitrile, dimethyl sulfoxide, dimethylformamide, chloroform, methylene chloride, carbon tetrachloride, ethyl acetate, hexane, and cyclohexane. Low-polarity benzene derivatives such as benzene, toluene, xylene, and mesitylene are particularly preferred because they allow for the preparation of solutions with suitable concentrations and prevent the materials contained in the ink from deteriorating due to oxidation. Furthermore, considering the uniformity of the resulting film and its thickness, solvents with a boiling point of 100°C or higher are preferred, with toluene, xylene, and mesitylene being even more preferred.

[0103] Note that the above structure can be combined as appropriate with other embodiments or other structures in this embodiment.

[0104] Furthermore, the organic compound having electron-transport properties contained in the electron-transport region 121 in the light-emitting device of one embodiment of the present invention can emit light with a wavelength (λ ) in the range of 455 nm to 465 nm. B ) is preferably 1.50 or more and 1.75 or less, or the ordinary refractive index for light with a wavelength of 633 nm is preferably 1.45 or more and 1.70 or less.

[0105] In this specification, the refractive index of the organic compound having electron transport properties, etc., is determined by measuring a thin film of the material. However, if anisotropy occurs in the material in such a thin film, the refractive index for ordinary light and the refractive index for extraordinary light may differ. If the thin film to be measured is in such a state, anisotropy analysis can be performed to separate the ordinary refractive index and the extraordinary refractive index and calculate each refractive index. In this specification, if the measured material has both an ordinary refractive index and an extraordinary refractive index, the ordinary refractive index is used as the index.

[0106] Since the electron transport region 121 contains such a material, it is possible to provide a layer with a low refractive index. By providing a layer with a low refractive index inside the EL layer, light extraction efficiency is improved, and a light-emitting element with high luminous efficiency can be obtained. Typically, the refractive index of an organic compound constituting a light-emitting device is about 1.8 to 1.9. The light-emitting device of one embodiment of the present invention can be a light-emitting device with high luminous efficiency by providing the electron transport region 121 having a layer with a low refractive index.

[0107] When the light-emitting device according to one embodiment of the present invention is a blue light-emitting device, the electron transport region 121 has a wavelength of λ B The electron transport region preferably includes a layer having an ordinary refractive index of 1.50 or more and less than 1.75, and more preferably 1.50 or more and less than 1.70, for light of λ. B The refractive index of ordinary light in this light is preferably 1.50 or more and 1.75 or less, and more preferably 1.50 or more and 1.70 or less.

[0108] In principle, the refractive index is larger on the short wavelength side and smaller on the long wavelength side. Therefore, the ordinary refractive index of the organic compound having electron-transport properties used in the electron-transport layer 114 of one embodiment of the present invention for light with a wavelength of 633 nm is preferably 1.45 or more and 1.70 or less.

[0109] The organic compound having an electron-transporting property preferably has an alkyl group or a cycloalkyl group, which can reduce the refractive index and realize the electron-transporting layer 114 having a low refractive index.

[0110] The alkyl group contained in the organic compound having electron transport properties is preferably a branched alkyl group, particularly preferably an alkyl group having 3 or 4 carbon atoms, and particularly preferably a tert-butyl group.

[0111] The organic compound having electron transport properties preferably includes an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, a plurality of aromatic hydrocarbon rings each having 6 to 14 carbon atoms forming the ring, at least two of the aromatic hydrocarbon rings being benzene rings, and a plurality of hydrocarbon groups bonding via sp3 hybrid orbitals.

[0112] In addition, in such an organic compound, the ratio of the number of carbon atoms forming bonds with sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound is preferably 10% or more and 60% or less, more preferably 10% or more and 50% or less. 1 In the results of measuring the organic compound by H-NMR, the integral value of signals below 4 ppm is preferably at least half the integral value of signals at 4 ppm or higher.

[0113] It is preferable that all of the hydrocarbon groups forming bonds through sp3 hybrid orbitals possessed by the organic compound are bonded to the aromatic hydrocarbon ring having 6 to 14 carbon atoms forming the ring, and that the LUMO of the organic compound is not distributed in the aromatic hydrocarbon ring.

[0114] The organic compound having electron transport properties is preferably contained in the electron transport layer 114 in the electron transport region 121 .

[0115] The organic compound having an electron transport property is preferably an organic compound represented by the following general formula (G1).

[0116] [ka]

[0117] In the formula, A represents a 6-membered heteroaromatic ring containing 1 to 3 nitrogen atoms, and is preferably a pyridine ring, a pyrimidine ring, a pyrazine ring, a pyridazine ring, or a triazine ring.

[0118] Also, R 0 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and a substituent represented by formula (G1-1).

[0119] R 1 ~R 15 At least one of R is a phenyl group having a substituent, and the others each independently represent any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, a substituted or unsubstituted ring-forming aromatic hydrocarbon group having 6 to 14 carbon atoms, and a substituted or unsubstituted pyridyl group. 1 , R 3 , R 5 , R 6 , R 8 , R 10 , R 11 , R 13 and R 15 is preferably hydrogen. The phenyl group having a substituent has one or two substituents, each of which is independently any one of an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 carbon atoms in a ring.

[0120] The organic compound represented by the general formula (G1) has a plurality of hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups 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.

[0121] Moreover, the organic compound having the electron transport property is preferably an organic compound represented by the following general formula (G3).

[0122] [ka]

[0123] In the formula, Q 1 ~Q 3 2 or 3 of the groups represent N, and the Q 1 ~Q 3 If two of the groups are N, the remaining group represents CH.

[0124] Also R 1 ~R 15 At least one of R is a phenyl group having a substituent, and the others each independently represent any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, a substituted or unsubstituted ring-forming aromatic hydrocarbon group having 6 to 14 carbon atoms, and a substituted or unsubstituted pyridyl group. 1 , R 3 , R 5 , R 6 , R 8 , R 10 , R 11 , R 13 and R 15 is preferably hydrogen. The phenyl group having a substituent has one or two substituents, each of which is independently any one of an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, and a substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 carbon atoms in a ring.

[0125] The organic compound represented by the general formula (G3) has a plurality of hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the ratio of the 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.

[0126] In the organic compound represented by the general formula (G1) or (G3), the substituted phenyl group is preferably a group represented by the following formula (G1-2).

[0127] [ka]

[0128] In the formula, α represents a substituted or unsubstituted phenylene group, and is preferably a phenylene group substituted at the meta position. Furthermore, 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 tert-butyl group.

[0129] R 20 represents an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 14 carbon atoms in a ring.

[0130] Furthermore, m and n represent 1 or 2. When m is 2, the multiple α may be the same or different. When n is 2, the multiple R 20 may be the same or different. 20 is preferably a phenyl group, and is a phenyl group having an alkyl group having 1 to 6 carbon atoms or an alicyclic group having 3 to 10 carbon atoms at one or both of the two meta positions. The substituents that the phenyl group has at one or both of the two meta positions are more preferably alkyl groups having 1 to 6 carbon atoms, and even more preferably tert-butyl groups.

[0131] In the light-emitting device of one embodiment of the present invention, the electron-transport layer 114 in the electron-transport region 121 preferably contains a metal complex of an alkali metal together with an organic compound having electron-transport properties. The metal complex of the alkali metal is preferably a lithium complex. The ligand of the metal complex is preferably a ligand having an 8-quinolinolato structure, such as 8-quinolinolato-lithium.

[0132] Furthermore, the ligand containing the 8-quinolinolato structure preferably has an alkyl group, and when the lithium complex containing the ligand containing the 8-quinolinolato structure has an alkyl group, the complex preferably has only one alkyl group. Furthermore, the alkyl group contained in the alkali metal complex preferably has one to three carbon atoms, and is particularly preferably a methyl group. An 8-quinolinolato-lithium having an alkyl group can be used as a metal complex with a low refractive index. Specifically, the ordinary refractive index for light in the wavelength range of 455 nm to 465 nm in a thin film state can be 1.45 to 1.70, and the ordinary refractive index for light with a wavelength of 633 nm can be 1.40 to 1.65.

[0133] In particular, the use of 6-alkyl-8-quinolinolato-lithium having an alkyl group at position 6 has the effect of reducing the driving voltage of a light-emitting device. Among 6-alkyl-8-quinolinolato-lithiums, it is more preferable to use 6-methyl-8-quinolinolato-lithium.

[0134] Here, the 6-alkyl-8-quinolinolatolithium is represented by the following general formula (G lq 1) can be expressed as follows.

[0135] [ka]

[0136] In the above general formula (G1), R represents an alkyl group having 1 to 3 carbon atoms.

[0137] A more preferred embodiment of the metal complex represented by the general formula (G1) is a metal complex represented by the following structural formula (100).

[0138] [ka]

[0139] As described above, the organic compound having electron-transport properties used in the electron-transport layer 114 of the light-emitting device according to one embodiment of the present invention preferably has an alkyl group having 3 or 4 carbon atoms. In particular, the organic compound having electron-transport properties preferably has a plurality of such alkyl groups. However, since too many alkyl groups in a molecule reduces the carrier transport property, the proportion of carbon atoms forming bonds with sp3 hybrid orbitals in the organic compound having electron-transport properties is preferably 10% to 60%, more preferably 10% to 50%, of the total number of carbon atoms in the organic compound. An organic compound having electron-transport properties with such a structure can achieve a low refractive index without significantly impairing the electron-transport property.

[0140] In addition, such organic compounds 1 When measured by H-NMR (proton nuclear magnetic resonance), the integral value of signals below 4 ppm exceeds the integral value of signals above 4 ppm.

[0141] Here, it is generally believed that the presence of an alkyl group or a cycloalkyl group inhibits the interaction (also referred to as docking) between an organic compound having electron-transport properties and a metal complex of an alkali metal, resulting in an increase in driving voltage. However, in the light-emitting device of one embodiment of the present invention, a large increase in driving voltage can be avoided by providing a light-emitting device with a low refractive index layer in the electron-transport region 121, thereby achieving good light-emitting efficiency.

[0142] Next, other examples of the structure and materials of the light-emitting device of one embodiment of the present invention will be described. As described above, the light-emitting device of one embodiment of the present invention includes the EL layer 103 composed of multiple layers between a pair of electrodes, the anode 101 and the cathode 102. The EL layer 103 includes the light-emitting layer 113 containing a light-emitting material, and the hole-transporting region 120 and the electron-transporting region 121 each having the above-described structure.

[0143] The anode 101 is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a large work function (specifically, 4.0 eV or higher). Specific examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are typically formed by sputtering, but they may also be formed by applying a sol-gel method. For example, indium zinc oxide may be formed by sputtering using a target containing indium oxide and 1 to 20 wt% zinc oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) may also be formed by sputtering using a target containing indium oxide and 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide. Other examples of materials that can be used for the anode 101 include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), and nitrides of metal materials (e.g., titanium nitride). Graphene can also be used as the material for the anode 101. By using a composite material (described later) in the layer of the EL layer 103 that is in contact with the anode 101, it becomes possible to select an electrode material regardless of the work function.

[0144] When the anode 101 is formed from a material that is transparent to visible light, a light-emitting device that emits light from the anode side can be formed as shown in Fig. 1C. When the anode 101 is formed on the substrate side, such a light-emitting device can be a so-called top-emission type light-emitting device.

[0145] The EL layer 103 preferably has a laminated structure, but the laminated structure is not particularly limited, and various layer structures can be used, such as a hole injection layer, a hole transport layer, an emitting layer, an electron transport layer, an electron injection layer, a carrier blocking layer (hole blocking layer, electron blocking layer), an exciton blocking layer, and a charge generation layer. Note that any of the layers may be omitted. In this embodiment, two types of structures are described: a structure in which, in addition to the emitting layer 113, a hole injection layer 111 and a hole transport layer 112 are included in the hole transport region 120, and an electron transport layer 114 and an electron injection layer 115 are included in the electron transport region 121, as shown in FIG. 1A; and a structure in which, as shown in FIG. 1B, a charge generation layer 116 is included instead of the electron injection layer 115 in FIG. 1A. The materials constituting each layer are specifically described below.

[0146] The light-emitting layer 113 contains a light-emitting substance and a host material. The light-emitting layer 113 may also contain other materials. The light-emitting layer 113 may also be a laminate of multiple layers with different compositions.

[0147] The light-emitting material may be a fluorescent material, a phosphorescent material, a material that exhibits thermally activated delayed fluorescence (TADF), or any other light-emitting material.

[0148] Examples of materials that can be used as the fluorescent substance in the light-emitting layer 113 include the following: In addition, fluorescent substances other than these can also be used.

[0149] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9 -diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviated as DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(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: 2DPAB PhA), 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 amine (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),6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyren-diyl)bis[(6-phenylbenzo[b ]naphtho[1,2-d]furan)-8-amine] (abbreviated as 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds, such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because of their high hole-trapping properties, excellent luminous efficiency, and reliability.

[0150] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, examples of materials that can be used include the following.

[0151] Organometallic iridium complexes with a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviated as [Ir(Mptz)3]), and tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviated as [Ir(iPrptz-3b)3]), and tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) Organometallic iridium complexes with a 1H-triazole skeleton, such as tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz1-mp)3]) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), organometallic iridium complexes with an imidazole skeleton, such as fac-tris[(1-2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’] Organometallic iridium complexes with phenylpyridine derivatives bearing electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as FIracac), are compounds that exhibit blue phosphorescence, with peak emission in the wavelength range from 440 nm to 520 nm.

[0152] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6- Organometallic iridium complexes with a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]) and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), and tris(2-phenylpyridinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’ Examples of suitable iridium complexes include organometallic iridium complexes having a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), and rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). These compounds mainly exhibit green phosphorescence, with an emission peak in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because of their outstanding reliability and luminous efficiency. In a light-emitting device according to one embodiment of the present invention, it is particularly preferred to use an iridium complex represented by the following structural formula as the light-emitting material. The following iridium complex has an alkyl group, making it easily soluble in organic solvents and easy to prepare a varnish.

[0153] [ka]

[0154] When an emitting layer containing the iridium complex represented by the above structural formula is measured by ToF-SIMS, it has been found that signals appear at m / z=1676 and product ions at m / z=1181 and m / z=685 in the positive mode.

[0155] In addition, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’ Examples include organometallic iridium complexes with a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviated as [Ir(piq)2(acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviated as PtOEP), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]). These compounds exhibit red phosphorescence, with peak emission in the wavelength range of 600 to 700 nm. Furthermore, organometallic iridium complexes having a pyrazine skeleton can emit red light with good chromaticity.

[0156] In addition to the phosphorescent compounds described above, known phosphorescent compounds may be selected and used.

[0157] TADF materials include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also available are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP), all of which are shown in the following structural formulas.

[0158] [ka]

[0159] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 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: P Heterocyclic compounds having either or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron-deficient heteroaromatic ring, pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptor properties and good reliability. Furthermore, among the skeletons having a π-electron-rich heteroaromatic ring, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable.The furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. The pyrrole skeleton is particularly preferably an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because the electron-donating ability of the π-electron-rich heteroaromatic ring and the electron-accepting ability of the π-electron-deficient heteroaromatic ring are both enhanced, thereby reducing the energy difference between the S1 level and the T1 level, thereby enabling efficient thermally activated delayed fluorescence. Instead of the π-electron-deficient heteroaromatic ring, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used. The π-electron-rich skeleton may be, for example, an aromatic amine skeleton or a phenazine skeleton. Examples of usable π-electron-deficient skeletons include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring or 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, etc. In this way, a π-electron-deficient skeleton or a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0160] [ka]

[0161] TADF materials are materials with a small difference between the S1 and T1 levels, and have the ability to convert triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy (reverse intersystem crossing) using a small amount of thermal energy, allowing for efficient generation of a singlet excited state. Triplet excitation energy can also be converted into light emission.

[0162] Furthermore, exciplexes (also known as exciplexes), which form an excited state with two types of substances, have an extremely small difference between the S1 and T1 levels and function as TADF materials that can convert triplet excitation energy into singlet excitation energy.

[0163] The phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K) can be used as an indicator of the T1 level. For a TADF material, when a tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side and the energy of the wavelength of the extrapolated line is defined as the S1 level, and a tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0164] When a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0165] As the host material of the light-emitting layer, various carrier transporting materials such as a material having an electron transporting property, a material having a hole transporting property, or the above-mentioned TADF material can be used.

[0166] As a material having hole transport properties, 1×10 -6 cm 2It is preferable that the compound has a hole mobility of 1000 uV or more. In particular, an organic compound having an amine skeleton or a π-electron-rich heteroaromatic skeleton is preferable, and examples thereof include 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)-N-phenylamino]biphenyl (abbreviation: BSPB), and the like. 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: PCBBi1BP), phenylamine (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]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), etc. Compounds with an aromatic amine skeleton, compounds with a carbazole skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), and compounds with an aromatic amine skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of suitable compounds include compounds having a thiophene skeleton, such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton, such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage.

[0167] In addition, 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 N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenyl 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-(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)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-Diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-Diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-Diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4 ''-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-fluoren-2-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), ... N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, and the like can also be suitably used.

[0168] Examples of materials having electron transport properties include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), as well as organic compounds having a π-electron-deficient heteroaromatic ring skeleton. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole] (abbreviation: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,2,4-triazole] ... [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-1 Heterocyclic compounds with polyazole skeletons such as H-benzimidazole (abbreviated as mDBTBIm-II), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTBPDBq-II), and 2-[3' Heterocyclic compounds with diazine skeletons such as 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and 3,Heterocyclic compounds with a pyridine skeleton, such as 5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-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(9 Examples of heterocyclic compounds having a triazine skeleton include 2-{3-[3-(benzo"b"naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), and 2-{3-[3-(benzo"b"naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02). Among the 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 high reliability. In particular, heterocyclic compounds with a diazine (pyrimidine or pyrazine) skeleton and heterocyclic compounds with a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0169] The TADF materials that can be used as host materials are the same as those listed above. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy through reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0170] This is very effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0171] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material, as this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient light emission.

[0172] Furthermore, to efficiently generate singlet excitation energy from triplet excitation energy through reverse intersystem crossing, carrier recombination is preferred in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to triplet excitation energy in the fluorescent material. To achieve this, the fluorescent material preferably has a protecting group around the luminophore (the skeleton responsible for light emission) of the fluorescent material. The protecting group is preferably a substituent without a π bond, and is preferably a saturated hydrocarbon. Specific examples include alkyl groups with 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups with 3 to 10 carbon atoms, and trialkylsilyl groups with 3 to 10 carbon atoms. Multiple protecting groups are even more preferred. Substituents without a π bond have poor carrier transport properties, allowing for the distance between the TADF material and the luminophore of the fluorescent material to be increased without significantly affecting carrier transport or carrier recombination. Here, the term "luminophore" refers to the atomic group (skeleton) responsible for light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring. Examples of the fused aromatic ring or the fused 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, or a naphthobisbenzofuran skeleton are preferred because of their high fluorescence quantum yield.

[0173] When a fluorescent emitting substance is used as the emitting substance, a material having an anthracene skeleton is suitable as the host material. Using a substance having an anthracene skeleton as the host material for a fluorescent emitting substance makes it possible to realize an emitting layer with both excellent luminous efficiency and durability. As a substance having an anthracene skeleton to be used as a host material, a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferred due to its chemical stability. Furthermore, host materials having a carbazole skeleton are preferred because of their enhanced hole injection and transport properties. However, host materials containing a benzocarbazole skeleton, in which a benzene ring is further condensed to carbazole, are even more preferred because their HOMO is approximately 0.1 eV shallower than that of carbazole, facilitating hole insertion. In particular, host materials containing a dibenzocarbazole skeleton are preferred because their HOMO is approximately 0.1 eV shallower than that of carbazole, facilitating hole insertion, and also exhibiting excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). From the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such a substance 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), and 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole. Examples include 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), and 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth).In particular, CzPA, cgDBCzPA2mBnfPPA, and PCzPA are preferable choices because they exhibit very good properties.

[0174] The host material may be a mixture of multiple substances, and when a mixture of host materials is used, it is preferable to mix a material having electron-transporting properties with a material having hole-transporting properties. By mixing a material having electron-transporting properties with a material having hole-transporting properties, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can also be easily controlled. The weight ratio of the content of the material having hole-transporting properties to the material having electron-transporting properties may be 1:19 to 19:1 (material having hole-transporting properties:material having electron-transporting properties).

[0175] A phosphorescent material can be used as part of the mixed material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as a light-emitting material.

[0176] Furthermore, these mixed materials may form an exciplex. It is preferable to select a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, because this allows for smooth energy transfer and efficient light emission. Furthermore, using this structure is also preferable because it reduces the driving voltage.

[0177] At least one of the materials forming the exciplex may be a phosphorescent material, which allows efficient conversion of triplet excitation energy into singlet excitation energy through reverse intersystem crossing.

[0178] 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. It is also preferable that the LUMO level of the hole-transporting material is equal to or higher than the LUMO level of the electron-transporting material. The LUMO and HOMO levels of the materials can be derived from the electrochemical properties (reduction potential and oxidation potential) of the materials measured by cyclic voltammetry (CV).

[0179] The formation of exciplexes can be confirmed by, for example, comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film of these materials and observing the phenomenon that the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak at longer wavelengths). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and a mixed film of these materials and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lived component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL can also be interpreted as transient electroluminescence (EL). In other words, the formation of exciplexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and a mixed film of these materials and observing differences in transient response.

[0180] Since the electron transport layer 114 has the configuration of the present invention, it can be made a layer with a low refractive index. Therefore, a layer with a low refractive index can be formed inside the EL layer 103 without significantly reducing the driving voltage, and the external quantum efficiency of the light-emitting device can be improved.

[0181] The electron transport layer 114 having this structure may also serve as the electron injection layer 115.

[0182] In addition, it is preferable that the alkali metal or the metal complex of the alkali metal in the electron transport layer 114 has a concentration difference (including a case where the difference is 0) in the thickness direction.

[0183] Between the electron transport layer 114 and the cathode 102, a layer containing an alkali metal or alkaline earth metal, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), or 8-hydroxyquinolinato-lithium (abbreviated as Liq), or a compound or complex thereof, may be provided as the electron injection layer 115. The electron injection layer 115 may be a layer made of a substance having electron transport properties containing an alkali metal or alkaline earth metal or a compound thereof, or an electride. Examples of the electride include a substance in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum.

[0184] Furthermore, the use of sodium fluoride is preferable because it improves the electron transport property and water resistance of the light-emitting device. When the electron injection layer 115 of a light-emitting device having sodium fluoride in it is analyzed by ToF-SIMS, NaF + or NaF2 - , Na2F3 - Signals originating from anions or cations with various numbers of sodium and fluorine bonds are observed.

[0185] Furthermore, a layer containing an alkaline earth metal such as barium may be provided in contact with the cathode, which is preferable because it improves electron injection properties from the cathode.

[0186] The barium-containing layer may also contain a heteroaromatic compound, preferably an organic compound having a phenanthroline skeleton, such as 2-phenyl-9-[3-(9-phenyl-1,10-phenanthroline-2-yl)phenyl]-1,10-phenanthroline, as shown in the following structural formula:

[0187] [ka]

[0188] When a layer containing 2-phenyl-9-[3-(9-phenyl-1,10-phenanthroline-2-yl)phenyl]-1,10-phenanthroline is analyzed by ToF-SIMS, a signal is observed at m / z=587 in both positive and negative modes. Furthermore, when this same material is deposited, if the same layer or an adjacent layer contains alkali metals or alkaline earth metals or their compounds, ions such as alkali metal complexes (e.g., Na complexes at m / z=609) or alkaline earth metal complexes (e.g., Ba complexes at m / z=724) may be detected.

[0189] Note that a layer containing a fluoride of the alkali metal or alkaline earth metal in a concentration (50 wt % or more) sufficient to form a microcrystalline state in a substance having an electron transport property (preferably an organic compound having a bipyridine skeleton) can also be used as the electron-injection layer 115. Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0190] Furthermore, a charge generation layer 116 may be provided instead of the electron injection layer 115 of FIG. 1A (FIG. 1B). The charge generation layer 116 is a layer that can inject holes into a layer in contact with the cathode side of the layer and electrons into a layer in contact with the anode side of the layer 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 above as a material that can form the hole injection layer 111. The P-type layer 117 may also be formed by laminating a film containing an acceptor material and a film containing a hole transport material, both of which are materials that form the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the cathode 102, which is the cathode, and the light-emitting device operates.

[0191] It is preferable that the charge generating layer 116 be provided with either or both of an electron relay layer 118 and an electron injection buffer layer 119 in addition to the P-type layer 117 .

[0192] The electron relay layer 118 contains at least a substance having electron transport properties and has the function of preventing 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 of the electron transport layer 114 that is in contact with the charge generation layer 116. The specific energy level of the LUMO level of the substance having electron transport properties used in the electron relay layer 118 is −5.0 eV or higher, preferably −5.0 eV or higher and −3.0 eV or lower. Note that the substance having electron transport properties used in the electron relay layer 118 is preferably a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0193] The electron injection buffer layer 119 can be made of a material with high electron injection properties, such as alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)).

[0194] Furthermore, when the electron injection buffer layer 119 is formed to contain a substance having electron transport properties and a donor substance, examples of the donor substance that can be used include alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), and rare earth metal compounds (including oxides, halides, and carbonates)), as well as organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, and decamethylnickelocene.

[0195] The substance having an electron-transporting property can be formed using the same material as the material for forming the electron-transporting layer 114 described above. Since the material is an organic compound with a low refractive index, by using the material for the electron-injection buffer layer 119, a light-emitting device with good external quantum efficiency can be obtained.

[0196] Materials that can be used to form the cathode 102 include metals, alloys, electrically conductive compounds, and mixtures thereof that have a low work function (specifically, 3.8 eV or less). 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), 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 can be used for the cathode 102, regardless of the magnitude of the work function, such as Al, Ag, ITO, and indium oxide-tin oxide containing silicon or silicon oxide.

[0197] When the cathode 102 is made of a material that is transparent to visible light, a light-emitting device that emits light from the cathode side can be formed, as shown in Fig. 1D. When the anode 101 is fabricated on the substrate side of a light-emitting device having such a cathode, it can be a so-called top-emission light-emitting device.

[0198] These conductive materials can be formed into films by dry methods such as vacuum deposition and sputtering, inkjet methods, spin coating methods, etc. Alternatively, they may be formed by wet methods using a sol-gel method, or by wet methods using a paste of a metal material.

[0199] In addition, various methods, whether dry or wet, can be used to form the EL layer 103. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating may be used.

[0200] Furthermore, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0201] The configuration of the layer provided between the anode 101 and the cathode 102 is not limited to the above. However, a configuration in which a light-emitting region where holes and electrons recombine is provided at a location away from the anode 101 and the cathode 102 is preferable, so as to suppress quenching caused by the proximity of the light-emitting region to the metals used in the electrodes and the carrier injection layer.

[0202] Furthermore, the hole transport layer and 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, are preferably made of a material having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer, in order to suppress energy transfer from excitons generated in the light-emitting layer.

[0203] Next, an embodiment of a light-emitting device (also called a stacked element or tandem element) having a configuration in which multiple light-emitting units are stacked will be described. This light-emitting device has multiple light-emitting units between an anode and a cathode. One light-emitting unit has a configuration substantially similar to that of the EL layer 103 shown in FIG. 1A. In other words, a tandem element is a light-emitting device having multiple light-emitting units, and the light-emitting device shown in FIG. 1A or 1B can be said to be a light-emitting device having one light-emitting unit.

[0204] In a tandem element, a first light-emitting unit and a second light-emitting unit are stacked between an anode and a cathode, and a charge generation layer is provided between the first light-emitting unit and the second light-emitting unit. The anode and cathode correspond to anode 101 and cathode 102 in FIG. 1A, respectively, and the same as those described in the description of FIG. 1A can be applied. Furthermore, the first light-emitting unit and the second light-emitting unit may have the same or different configurations.

[0205] The charge generation layer in a tandem element has the function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied between the anode and the cathode. In other words, when a voltage is applied so 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 inject holes into the second light-emitting unit.

[0206] The charge generation layer is preferably formed to have the same structure as the charge generation layer 116 described in FIG. 1B. A composite material of an organic compound and a metal oxide has excellent carrier injection and carrier transport properties, and therefore can achieve low-voltage driving and low-current driving. Note that when the anode side surface of the light-emitting unit is in contact with the charge generation layer, the charge generation layer can also serve as the hole injection layer of the light-emitting unit, and therefore the light-emitting unit does not need to be provided with a hole injection layer.

[0207] Furthermore, when the electron injection buffer layer 119 is provided in the charge generation layer of a tandem element, the electron injection buffer layer 119 plays the role of an electron injection layer in the light-emitting unit on the anode side, and therefore it is not necessarily required to form an electron injection layer in the light-emitting unit on the anode side.

[0208] While the above describes a tandem element having two light-emitting units, the same can be applied to a tandem element having three or more stacked light-emitting units. By arranging multiple light-emitting units between a pair of electrodes and separating them with a charge-generating layer, it is possible to achieve a device that emits high-intensity light while maintaining a low current density, and that has a long lifespan. It is also possible to realize a light-emitting device that can be driven at a low voltage and consumes little power.

[0209] Furthermore, by making each light-emitting unit emit a different light color, the light-emitting device as a whole can emit light of a desired color. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green light from the first light-emitting unit and blue light from the second light-emitting unit.

[0210] The above-described EL layer 103, the first light-emitting unit, the second light-emitting unit, the charge generation layer, and other layers and electrodes can be formed by, for example, vapor deposition (including vacuum deposition), droplet discharge (also called ink-jet method), coating, gravure printing, etc. They may also contain low-molecular-weight materials, medium-molecular-weight materials (including oligomers and dendrimers), or polymer materials.

[0211] This embodiment mode can be freely combined with other embodiment modes.

[0212] (Embodiment 2) In this embodiment, a light-emitting apparatus using the light-emitting device described in Embodiment 1 will be described.

[0213] 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. FIG. 2A is a top view showing the light-emitting device, and FIG. 2B is a cross-sectional view taken along dashed lines AB and CD shown in FIG. 2A. This light-emitting device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, to control light emission from the light-emitting device. Also, 604 denotes a sealing substrate, 605 denotes a sealant, and the inside surrounded by the sealant 605 forms a space 607.

[0214] The routing wiring 608 is wiring for transmitting signals input to the source line driver circuit 601 and the gate line driver circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from an FPC (flexible printed circuit) 609, which serves as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. In this specification, the light-emitting device includes not only the light-emitting device itself, but also a state in which an FPC or PWB is attached to it.

[0215] Next, the cross-sectional structure will be described with reference to Fig. 2B. A driver circuit section and a pixel section are formed on an element substrate 610, but here, a source line driver circuit 601, which is the driver circuit section, and one pixel in a pixel section 602 are shown.

[0216] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like.

[0217] The structure of the transistors used in the pixels and driver circuits is not particularly limited. For example, they may be inverted staggered transistors or staggered transistors. Furthermore, they may be top-gate or bottom-gate transistors. The semiconductor material used for the transistors is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and gallium nitride. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used.

[0218] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0219] Here, it is preferable to use an oxide semiconductor for semiconductor devices such as transistors provided in the pixels and driver circuits, as well as transistors used in touch sensors, which will be described later. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0220] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0221] In particular, it is preferable to use, as the semiconductor layer, an oxide semiconductor film having a plurality of crystal parts whose c-axes are oriented perpendicular to the surface on which the semiconductor layer is formed or the top surface of the semiconductor layer and which does not have grain boundaries between adjacent crystal parts.

[0222] By using such a material for the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0223] Furthermore, a transistor having the above-described semiconductor layer can retain charge stored in a capacitor through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop the driving circuit while maintaining the gradation of an image displayed in each display region. As a result, a light-emitting device with extremely low power consumption can be realized.

[0224] To stabilize the characteristics of the transistor, it is preferable to provide an underlayer film. The underlayer film can be formed as a single layer or a multilayer using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The underlayer film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, or a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, or the like. Note that the underlayer film need not be provided if it is not necessary.

[0225] Note that FET 623 represents one of the transistors formed in the drive circuit section 601. The drive circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In addition, although this embodiment shows a driver-integrated type in which the drive circuit is formed on a substrate, this is not necessarily required, and the drive circuit may also be formed externally rather than on the substrate.

[0226] Furthermore, the pixel section 602 is formed by a plurality of pixels each including a switching FET 611, a current control FET 612, and an anode 613 electrically connected to the drain of the FET, but is not limited to this, and the pixel section may be formed by combining three or more FETs and a capacitance element.

[0227] An insulator 614 is formed to cover the end of the anode 613. Here, it can be formed by using a positive photosensitive acrylic resin film.

[0228] Furthermore, in order to improve the coverage of an EL layer or the like to be formed later, a curved surface having a curvature is formed at the upper or lower end of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material for the insulator 614, it is preferable that only the upper end of the insulator 614 has a curved surface having a radius of curvature (0.2 μm to 3 μm). Furthermore, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0229] An EL layer 616 and a cathode 617 are formed on the anode 613. It is desirable to use a material with a large work function for the anode 613. For example, a single layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt % zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film can be used. It is also possible to use a laminated structure of a titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film. The laminated structure provides low resistance as wiring, good ohmic contact, and the anode can function well.

[0230] The EL layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an inkjet method, or a spin coating method. The EL layer 616 includes the components described in Embodiment 1. Other materials constituting the EL layer 616 may be low-molecular compounds or high-molecular compounds (including oligomers and dendrimers).

[0231] Furthermore, it is preferable to use a material with a small work function (Al, Mg, Li, Ca, or alloys or compounds thereof (MgAg, MgIn, AlLi, etc.)) as a material formed on the EL layer 616. When light generated in the EL layer 616 is transmitted through the cathode 617, it is preferable to use a laminate of a thin metal thin film and a transparent conductive film (ITO, indium oxide containing 2 to 20 wt % zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) as the cathode 617.

[0232] Note that a light-emitting device is formed with 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 a pixel portion is formed with a plurality of light-emitting devices, but the light-emitting device in this embodiment may include both the light-emitting device described in Embodiment 1 and light-emitting devices having other structures.

[0233] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealant 605, a structure is formed in which a light-emitting device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. The space 607 is filled with a filler, which may be filled with an inert gas (nitrogen, argon, etc.) or a sealant. A recess is formed in the sealing substrate and a desiccant is provided therein, which is a preferable configuration because it can suppress deterioration due to the influence of moisture.

[0234] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as moisture and oxygen impermeable as possible. In addition to glass and quartz substrates, plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, etc. can be used for the sealing substrate 604.

[0235] Although not shown in Figures 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. The protective film may also be formed so as to cover the exposed portion of the sealing material 605. The protective film may also be provided so as to cover the surfaces and side surfaces of the pair of substrates, the exposed side surfaces of the sealing layer, the insulating layer, etc.

[0236] The protective film can be made of a material that is impermeable to impurities such as water, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0237] The protective film may be made of an oxide, a nitride, a fluoride, a sulfide, a ternary compound, a metal, a polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, or the like; a nitride containing titanium and aluminum; an oxide containing titanium and aluminum; an oxide containing aluminum and zinc; a sulfide containing manganese and zinc; a sulfide containing cerium and strontium; an oxide containing erbium and aluminum; or an oxide containing yttrium and zirconium.

[0238] The protective film is preferably formed using a film formation method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. In addition, it is possible to reduce damage to the workpiece when forming the protective film.

[0239] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on surfaces with complex uneven shapes, as well as on the top, side, and back surfaces of a touch panel.

[0240] In the above manner, a light-emitting device manufactured using the light-emitting device described in Embodiment 1 can be obtained.

[0241] The light-emitting device in this embodiment can have favorable characteristics because it uses the light-emitting device described in Embodiment 1. Specifically, the light-emitting device described in Embodiment 1 has favorable luminous efficiency, and therefore can have low power consumption.

[0242] 3A and 3B show an example of a light-emitting device in which a white-emitting light-emitting device is formed and a full color display is achieved by providing a colored layer (color filter), etc. Fig. 3A shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 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, and 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 sealant 1032, etc.

[0243] 3A, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) are provided on a transparent base material 1033. A black matrix 1035 may also be provided. The transparent base material 1033 on which the colored layers and black matrix are provided is aligned and fixed to the substrate 1001. The colored layers and black matrix 1035 are covered with an overcoat layer. Also, in FIG. 3A, there are light-emitting layers from which light does not pass through the colored layers and exits to the outside, and light-emitting layers from which light passes through the colored layers of each color and exits to the outside. Light that does not pass through the colored layers is white, and light that passes through the colored layers is red, green, and blue, so that an image can be displayed using four color pixels.

[0244] 3B shows an example in which colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. In this way, the colored layers may be provided between the substrate 1001 and the sealing substrate 1031.

[0245] Furthermore, the light-emitting device described above has a structure in which light is extracted from the substrate 1001 on which the FET is formed (bottom emission type), but it may also have a structure in which light is extracted from the sealing substrate 1031 (top emission type). A cross-sectional view of a top emission type light-emitting device is shown in FIG. 4. In this case, a light-opaque substrate can be used as the substrate 1001. The process is the same as for a bottom emission type light-emitting device until a connection electrode that connects the FET and the anode of the light-emitting device is fabricated. Thereafter, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also serve as a planarizing film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film, as well as other known materials.

[0246] Although the anodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are referred to as anodes in this example, they may be cathodes. Furthermore, in the case of a top-emission light-emitting device such as that shown in FIG. 4, it is preferable that the anodes be reflective electrodes. The EL layer 1028 has the same configuration as that described for the EL layer 103 in the first embodiment, and has an element structure that allows white light emission.

[0247] In the top-emission structure shown in FIG. 4, sealing can be performed using a sealing substrate 1031 provided with colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B). The sealing substrate 1031 may be provided with a black matrix 1035 positioned between pixels. The colored layers (the red colored layer 1034R, the green colored layer 1034G, and the blue colored layer 1034B) and the black matrix may be covered with an overcoat layer 1036. Note that a light-transmitting substrate is used as the sealing substrate 1031. In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, the present invention is not particularly limited, and full-color display using four colors, red, yellow, green, and blue, or three colors, red, green, and blue, may also be performed.

[0248] A microcavity structure is suitable for use in top-emission light-emitting devices. A light-emitting device with a microcavity structure can be obtained by using a reflective electrode as the anode and a semi-transparent / semi-reflective electrode as the cathode. At least an EL layer is present between the reflective electrode and the semi-transparent / semi-reflective electrode, and at least an emissive layer that serves as the light-emitting region is present.

[0249] The reflectance of the reflective electrode to visible light is 40% to 100%, preferably 70% to 100%, and the resistivity is 1×10 -2 The semi-transmitting and semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1×10 -2 It is assumed that the film has a resistance of Ωcm or less.

[0250] The light emitted from the light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transmissive and semi-reflective electrode, causing resonance.

[0251] In this light-emitting device, the optical distance between the reflective electrode and the semi-transparent / semi-reflective electrode can be changed by changing the thickness of the transparent conductive film, the composite material described above, the carrier transport material, etc. This makes it possible to intensify light with resonant wavelengths and attenuate light with non-resonant wavelengths between the reflective electrode and the semi-transparent / semi-reflective electrode.

[0252] Note that, since the light reflected by the reflective electrode and returned (first reflected light) significantly interferes with the light (first incident light) that directly enters the semi-transmissive-semi-reflective electrode from the light-emitting layer, 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 greater than or equal to 1, and λ is the wavelength of the emitted light to be amplified). By adjusting this optical distance, the phases of the first reflected light and the first incident light can be matched, thereby further amplifying the light emitted from the light-emitting layer.

[0253] In the above configuration, the EL layer may have a structure having multiple light-emitting layers or a structure having a single light-emitting layer. For example, it may be combined with the above-mentioned tandem light-emitting device configuration, in which multiple EL layers are provided in one light-emitting device with a charge-generating layer sandwiched therebetween, and one or more light-emitting layers are formed in each EL layer.

[0254] The microcavity structure makes it possible to increase the light emission intensity of specific wavelengths in the front direction, thereby reducing power consumption. In the case of a light-emitting device that displays images using four sub-pixels of red, yellow, green, and blue, not only is the yellow light emitted effective in improving brightness, but the microcavity structure that matches the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with good characteristics.

[0255] The light-emitting device in this embodiment can have favorable characteristics because it uses the light-emitting device described in Embodiment 1. Specifically, the light-emitting device described in Embodiment 1 has favorable luminous efficiency, and therefore can have low power consumption.

[0256] Up to this point, we have explained active matrix light-emitting devices. From here on, we will explain passive matrix light-emitting devices. FIGS. 5A and 5B show a passive matrix light-emitting device manufactured by applying the present invention. FIG. 5A is a perspective view of the light-emitting device, and FIG. 5B is a cross-sectional view of FIG. 5A taken along the dashed-dotted line XY. In FIG. 5, an EL layer 955 is provided between an electrode 952 and an electrode 956 on a substrate 951. The edge of the electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The sidewalls of the partition layer 954 are inclined such that the distance between one sidewall and the other sidewall narrows as the distance approaches the substrate surface. That is, the cross section of the partition layer 954 in the short side direction is trapezoidal, and the bottom side (the side facing the same direction as the surface of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the top side (the side facing the same direction as the surface of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this manner, defects in the light-emitting device due to static electricity or the like can be prevented. Furthermore, the light-emitting device described in Embodiment 1 is used in a passive matrix light-emitting device, and the light-emitting device can be highly reliable or consumes less power.

[0257] The light emitting device described above is capable of individually controlling a large number of minute light emitting devices arranged in a matrix, and is therefore suitable for use as a display device for displaying images.

[0258] This embodiment mode can be freely combined with other embodiment modes.

[0259] (Embodiment 3) In this embodiment, an example in which the light-emitting device described in Embodiment 1 is used as a lighting device will be described with reference to Fig. 6. Fig. 6B is a top view of the lighting device, and Fig. 6A is a cross-sectional view taken along line ef shown in Fig. 6B.

[0260] In the lighting device of this embodiment, an anode 401 is formed on a light-transmitting substrate 400, which serves as a support. The anode 401 corresponds to the anode 101 in Embodiment 1. When light is extracted from the anode 401 side, the anode 401 is formed from a light-transmitting material.

[0261] A pad 412 for supplying a voltage to the cathode 404 is formed on the substrate 400 .

[0262] An EL layer 403 is formed on the anode 401. The EL layer 403 has a structure corresponding to the EL layer 103 in the first embodiment. For details of the structure, please refer to the description therein.

[0263] Cathode 404 is formed to cover EL layer 403. Cathode 404 corresponds to cathode 102 in Embodiment 1. When light is extracted from the anode 401 side, cathode 404 is formed of a material with high reflectivity. Cathode 404 is connected to pad 412 to supply voltage.

[0264] As described above, the lighting device described in this embodiment has a light-emitting device including the anode 401, the EL layer 403, and the 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.

[0265] The lighting device is completed by bonding and sealing substrate 407, on which the light-emitting device having the above configuration is formed, to substrate 400 using sealants 405 and 406. Either sealant 405 or 406 can be used. Also, a desiccant can be mixed into inner sealant 406 (not shown in FIG. 6B), which can absorb moisture and improve reliability.

[0266] Furthermore, an external input terminal can be formed by extending a portion of the pad 412 and the anode 401 outside the sealing materials 405 and 406. An IC chip 420 equipped with a converter or the like may also be provided thereon.

[0267] As described above, the lighting device described in this embodiment uses the light-emitting device described in Embodiment 1 as its EL element, and can be a lighting device with low power consumption.

[0268] This embodiment mode can be freely combined with other embodiment modes.

[0269] (Fourth embodiment) In this embodiment, an example of an electronic device including the light-emitting device described in Embodiment 1 as a part thereof will be described. The light-emitting device described in Embodiment 1 has good light-emitting efficiency and low power consumption. As a result, the electronic device described in this embodiment can be an electronic device having a light-emitting portion with low power consumption.

[0270] Examples of electronic devices to which the light-emitting devices are applied include television sets (also called televisions or television receivers), computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game machines, personal digital assistants, sound players, large game machines such as pachinko machines, etc. Specific examples of these electronic devices are shown below.

[0271] 7A illustrates an example of a television set. The television set has a display portion 7103 incorporated in a housing 7101. Here, the housing 7101 is supported by a stand 7105. The display portion 7103 can display images, and the light-emitting devices described in Embodiment 1 are arranged in a matrix.

[0272] The television set can be operated using operation switches provided on the housing 7101 or a separate remote control 7110. Channels and volume can be controlled using operation keys 7109 provided on the remote control 7110, and images displayed on the display portion 7103 can be controlled. The remote control 7110 may be provided with a display portion 7107 that displays information output from the remote control 7110. Note that the light-emitting devices described in Embodiment 1 arranged in a matrix can also be applied to the display portion 7107.

[0273] The television device is configured to include a receiver, a modem, etc. The receiver can receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it is also possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0274] FIG. 7B1 shows a computer including a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. This computer is manufactured by using the light-emitting devices described in Embodiment 1 arranged in a matrix for the display portion 7203. The computer in FIG. 7B1 may have a configuration as shown in FIG. 7B2. The computer in FIG. 7B2 is provided with a display portion 7210 instead of the keyboard 7204 and the pointing device 7206. The display portion 7210 is a touch panel type, and input can be performed by operating an input display displayed on the display portion 7210 with a finger or a dedicated pen. The display portion 7210 can display not only an input display but also other images. The display portion 7203 may also be a touch panel. The two screens are connected by a hinge, which can prevent the screens from being scratched or broken during storage or transportation.

[0275] 7C shows an example of a mobile terminal. The mobile phone includes a display portion 7402 built into 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 the display portion 7402 in which the light-emitting devices described in Embodiment 1 are arranged in a matrix.

[0276] 7C can be configured so that information can be input by touching the display portion 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 portion 7402 with a finger or the like.

[0277] The screen of the display unit 7402 has three main modes. The first is a display mode that mainly displays images, the second is an input mode that mainly inputs information such as characters, and the third is a display+input mode that combines the display mode and the input mode.

[0278] For example, when making a call or creating an e-mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and characters displayed on the screen may be input. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402.

[0279] Furthermore, by providing a detection device having a sensor for detecting tilt, such as a gyroscope or an acceleration sensor, inside the mobile terminal, the orientation of the mobile terminal (portrait or landscape) can be determined and the screen display of the display portion 7402 can be automatically switched.

[0280] The screen mode can be switched by touching the display portion 7402 or by operating the operation buttons 7403 on the housing 7401. The screen mode can also be switched depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display portion is moving image data, the display mode is selected, and if it is text data, the input mode is selected.

[0281] In addition, in the input mode, a signal detected by an optical sensor of the display portion 7402 may be detected, and if there is no input by touch operation on the display portion 7402 for a certain period of time, the screen mode may be controlled to switch from the input mode to the display mode.

[0282] The display portion 7402 can also function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger to capture an image of a palm print, fingerprint, or the like. Furthermore, by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light for the display portion, finger veins, palm veins, or the like can also be captured.

[0283] Note that the structure described in this embodiment mode can be used by combining any of the structures described in Embodiment Modes 1 to 4 as appropriate.

[0284] As described above, the light-emitting device having the light-emitting device described in Embodiment 1 or 2 has a very wide range of application, and this light-emitting device can be applied to electronic devices in a wide range of fields. By using the light-emitting device described in Embodiment 1 or 2, electronic devices with low power consumption can be obtained.

[0285] FIG. 8A is a schematic diagram showing an example of a cleaning robot.

[0286] The cleaning robot 5100 has a display 5101 arranged on its top surface, multiple cameras 5102 arranged on its side, a brush 5103, and an operation button 5104. Although not shown, the cleaning robot 5100 is also provided with tires, a suction port, and the like on its bottom surface. The cleaning robot 5100 also has various other sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezoelectric sensor, an optical sensor, and a gyro sensor. The cleaning robot 5100 also has wireless communication means.

[0287] The cleaning robot 5100 can move by itself, detect dust 5120, and suck up the dust from a suction port provided on the bottom surface.

[0288] Furthermore, the cleaning robot 5100 can analyze the image captured by the camera 5102 to determine whether there are any obstacles such as walls, furniture, or steps. Furthermore, if the image analysis detects an object that may become tangled in the brush 5103, such as a wire, the rotation of the brush 5103 can be stopped.

[0289] The display 5101 can display the remaining battery level, the amount of dust that has been sucked up, etc. The path traveled by the cleaning robot 5100 may be displayed on the display 5101. The display 5101 may also be a touch panel, and an operation button 5104 may be provided on the display 5101.

[0290] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when he or she is away from home. In addition, the display on the display 5101 can be confirmed on the portable electronic device such as a smartphone.

[0291] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0292] The robot 2100 shown in FIG. 8B includes a computing device 2110, an illumination 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 movement mechanism 2108.

[0293] The microphone 2102 has a function of detecting the user's speaking voice, environmental sounds, etc. 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.

[0294] The display 2105 has a function of displaying various information. The robot 2100 can display information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may also be a detachable information terminal, which can be installed in a fixed position on the robot 2100 to enable charging and data transfer.

[0295] The upper camera 2103 and the lower camera 2106 have a function of capturing images of the surroundings of the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of an obstacle in the moving 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 of one embodiment of the present invention can be used for the display 2105.

[0296] 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 for measuring force, displacement, position, velocity, 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 light), a microphone 5008, a display unit 5002, a support unit 5012, and earphones 5013.

[0297] The light-emitting device of one embodiment of the present invention can be used for the display portion 5001 and the display portion 5002 .

[0298] 9 shows an example in which the light-emitting device described in Embodiment 1 is used in a desk lamp, which is a lighting device. The desk lamp shown in FIG. 9 includes a housing 2001 and a light source 2002, and the lighting device described in Embodiment 3 may be used as the light source 2002.

[0299] FIG. 10 shows an example in which the light-emitting device described in Embodiment 1 is used as an indoor lighting device 3001. The light-emitting device described in Embodiment 1 has high emission efficiency and can therefore be used as a lighting device with low power consumption. In addition, the light-emitting device described in Embodiment 1 can be made large in area and can therefore be used as a large-area lighting device. In addition, the light-emitting device described in Embodiment 1 is thin and can therefore be used as a thin lighting device.

[0300] The light-emitting device described in Embodiment 1 can also be mounted on a windshield or dashboard of an automobile. Figure 11 shows one mode in which the light-emitting device described in Embodiment 1 is used on a windshield or dashboard of an automobile. Display regions 5200 to 5203 are display regions provided using the light-emitting device described in Embodiment 1.

[0301] The display region 5200 and the display region 5201 are display devices equipped with the light-emitting device described in Embodiment 1 and provided on the windshield of an automobile. The light-emitting device described in Embodiment 1 can be a so-called see-through display device, in which the opposite side can be seen through, by fabricating the anode and cathode using light-transmitting electrodes. A see-through display can be installed on the windshield of an automobile without obstructing the view. Note that when a transistor or the like is provided for driving the device, a light-transmitting transistor such as an organic transistor made of an organic semiconductor material or a transistor using an oxide semiconductor is preferably used.

[0302] The display area 5202 is a display device provided on a pillar and incorporating the light-emitting device described in Embodiment 1. By displaying an image from an imaging means provided on the vehicle body in the display area 5202, the view blocked by the pillar can be complemented. Similarly, the display area 5203 provided on the dashboard can complement the view blocked by the vehicle body by displaying an image from an imaging means provided on the outside of the vehicle, thereby compensating for blind spots and improving safety. By displaying an image to complement the invisible parts, safety can be confirmed more naturally and without discomfort.

[0303] The display area 5203 can also provide various information such as navigation information, a speedometer, a tachometer, and air conditioning settings. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in the display areas 5200 to 5202. The display areas 5200 to 5203 can also be used as lighting devices.

[0304] 12A and 12B show a foldable mobile information terminal 5150. The foldable mobile information terminal 5150 has a housing 5151, a display area 5152, and a bending portion 5153. FIG. 12A shows the mobile information terminal 5150 in an unfolded state. FIG. 12B shows the mobile information terminal in a folded state. Although the mobile information terminal 5150 has a large display area 5152, it is compact and highly portable when folded.

[0305] Display area 5152 can be folded in half by bending portion 5153. Bending portion 5153 is composed of an expandable member and multiple support members, and when folding, the expandable member stretches and bending portion 5153 is folded with a curvature radius of 2 mm or more, preferably 3 mm or more.

[0306] 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.

[0307] 13A to 13C show a foldable mobile information terminal 9310. Fig. 13A shows the mobile information terminal 9310 in an unfolded state. Fig. 13B shows the mobile 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 mobile information terminal 9310 in a folded state. The mobile information terminal 9310 has excellent portability in a folded state, and has excellent display visibility due to a seamless, wide display area in an unfolded state.

[0308] 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.

[0309] <Reference example 1> This reference example shows the results of liquid chromatography mass spectrometry (LC / MS) analysis of 4,4'-[(2,2',3,3',5,5',6,6'-octafluoro[1,1'-biphenyl]-4,4'-diyl)bis(oxy)]bis[2,7-naphthalenesulfonic acid] (abbreviated as NSO-2), which was exemplified as (S-2) as one of the arylsulfonic acid compounds in Embodiment 1. The structural formula of NSO-2 is shown below.

[0310] [ka]

[0311] In the LC / MS analysis, LC (liquid chromatography) separation was performed using an Ultimate 3000 manufactured by Thermo Fisher Scientific, and MS analysis (mass spectrometry) was performed using a Q Exactive manufactured by Thermo Fisher Scientific.

[0312] For LC separation, an arbitrary column was used, the column temperature was set to 40°C, and the solvent was appropriately selected as the flow condition. The sample was prepared by dissolving NSO-2 at an arbitrary concentration in an organic solvent, and the injection volume was 5.0 μL.

[0313] MS / MS measurements of m / z 901.91, the exact mass of NSO-2, were performed using PRM. The PRM settings were for the target ion mass range of m / z 901.91 ± 2.0 (isolation window = 4), and detection was performed in negative mode. The energy used to accelerate the target ion in the collision cell, NCE (Normalized Collision Energy), was set to 50. The MS spectrum obtained from the MS / MS measurements is shown in Figure 18.

[0314] The product ion around m / z=205 is C 10 H5O3S ··- It is assumed to be a biradical anion of naphthalenesulfonic acid represented by The product ion around m / z=222 is C 10 H6O4S ·- It is assumed to be the radical anion of naphthalenesulfonic acid alcohol represented by The product ion around m / z=302 is C 10 H6O7S2 ·- It is assumed to be the radical anion of the naphthalenebisulfonic acid alcohol group represented by The product ion around m / z=661 is C 32 H 13 F8O5S - It is estimated to be an anion in which three sulfonic acid groups are substituted with hydrogen from NSO-2, The product ion around m / z=741 is C 32 H13 F8O8S2 - It is estimated that the anion is formed by replacing two sulfonic acid groups with hydrogen atoms from NSO-2, The product ion around m / z=821 is C 32 H 13 F8O 11 S3 - It is estimated that this is an anion in which one sulfonic acid group is substituted with hydrogen from NSO-2, The product ion around m / z=535 is C 22 H7F8O5S - It is estimated that the anion is formed by replacing one sulfonic acid group and one naphthalenebisulfonic acid group with hydrogen from NSO-2, The product ion around m / z=80 is O3S ·- These results suggest that NSO-2 contains sulfone and ether groups, and two naphthalenebisulfonic acid ether groups.

[0315] In addition, the product ion around m / z=328 is C 12 F8O2 ·- This suggests that NSO-2 contains two naphthalenebisulfonic acids, each bonded to the octafluorobiphenyl group by an ether bond.

[0316] It should be noted that the mass numbers of these detected ions may be ±2 of the product ions due to the addition and desorption of protons.

[0317] As described above, in negative mode MS analysis, product ions with mass numbers 241, 161, or 81 less than the mass range of the target ion ±2.0 (isolation window = 4) suggest that one or more sulfonic groups have been eliminated, and a hole injection layer that can detect such product ions is preferable.

[0318] <Reference example 2> In this reference example, a mixed film of 4,4'-[(2,2',3,3',5,5',6,6'-octafluoro[1,1'-biphenyl]-4,4'-diyl)bis(oxy)]bis[2,7-naphthalenesulfonic acid] (abbreviated as NSO-2), which was exemplified as one of the arylsulfonic acid compounds (S-2) in Embodiment 1, and diphenylaminodiphenylamine (abbreviated as DPA) was evaluated using electron spin resonance (ESR). The structural formulas of NSO-2 and DPA are shown below.

[0319] [ka]

[0320] <<Preparation method of sample 1 (mixed thin film of NSO-2 and DPA)>> NSO-2 and DPA were dissolved in N,N-dimethylformamide (DMF) in a 1:8 (mol) ratio. The resulting solution was dropped onto a quartz substrate to form a film. The resulting film-formed substrate was dried on a hot plate at approximately 150°C to obtain Sample 1.

[0321] <<Preparation method of comparative sample 1 (NSO-2 thin film)>> NSO-2 was dissolved in DMF, and the resulting solution was dropped onto a quartz substrate to form a film. The resulting film-formed substrate was dried on a hot plate at approximately 150°C to obtain Comparative Sample 1.

[0322] <<Preparation method of comparative sample 2 (DPA thin film)>> DPA was dissolved in DMF. The resulting solution was dropped onto a quartz substrate to form a film. The resulting film-formed substrate was dried on a hot plate at approximately 150°C to obtain Comparative Sample 2.

[0323] <ESR measurement and results> The quartz substrate on which the above sample was formed was cut into pieces, placed in a quartz tube, and measured. The ESR spectrum from an empty quartz tube was subtracted from the ESR spectrum obtained. The results of ESR measurement of the prepared sample are shown in Figure 19. Figure 19 shows the ESR spectrum of the measured film.

[0324] The electron spin resonance spectrum was measured by the ESR method using an electron spin resonance measuring device, JES FA300 (manufactured by JEOL Ltd.). The measurements were performed at room temperature with a resonance frequency of approximately 9.2 GHz, an output of 1 mW, a modulation magnetic field of 50 mT, a modulation width of 0.5 mT, a time constant of 0.03 sec, and a sweep time of 4 min. 2+ Magnetic field correction was performed based on the positions of the third and fourth signals.

[0325] As a result of the measurements, a significantly strong signal was obtained from the spectrum of the mixed film of NSO-2 and DPA. The g value calculated from the peak of this spectrum was approximately 2.00. This g value (g = 2.00) is derived from the half-occupied orbitals formed by the interaction between NSO-2 and DPA. On the other hand, such a strong signal was not detected from the single film of NSO-2 or single film of DPA.

[0326] From the above, it was found that the mixed film or mixture of a sulfonic acid compound and a secondary amine compound according to one embodiment of the present invention significantly increases the spin density at a g value of approximately 2.00 (±0.05) compared to that of the mixture without the compound. This suggests that carriers are generated. Therefore, it is suggested that the use of a mixed film containing these compounds in the hole injection layer can result in a device with excellent hole injection properties.

[0327] <Reference example 3> ≪Reference synthesis example 1≫ Example 1 This example describes a synthesis method for 6-methyl-8-quinolinolato-lithium (abbreviation: Li-6mq) described in Embodiment 1. The structural formula of Li-6mq is shown below.

[0328] [ka]

[0329] 2.0 g (12.6 mmol) of 8-hydroxy-6-methylquinoline and 130 mL of anhydrous tetrahydrofuran (THF) were placed in a three-neck flask and stirred. 10.1 mL (10.1 mmol) of a 1 M THF solution of lithium tert-butoxide (tBuOLi) was added to this solution and stirred at room temperature for 47 hours. The reaction solution was concentrated to give a yellow solid. Acetonitrile was added to this solid, and the mixture was subjected to ultrasonic irradiation and filtration to give a pale yellow solid. This washing procedure was repeated twice. 1.6 g (95% yield) of a pale yellow solid of Li-6mq was obtained as the filtrate. The synthesis scheme is shown below.

[0330] [ka]

[0331] Next, the absorption spectrum and emission spectrum of Li-6mq in anhydrous acetone solution were measured, and the results are shown in Figure 14. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation), and the spectrum measured by placing only anhydrous acetone in a quartz cell was subtracted from the absorption spectrum. The emission spectrum was measured using a fluorometer (FP-8600, manufactured by JASCO Corporation).

[0332] As can be seen from FIG. 14, the dehydrated acetone solution of Li-6mq exhibited an absorption peak at 390 nm and an emission wavelength peak at 540 nm (excitation wavelength 385 nm).

[0333] <Reference example 4> ≪Reference synthesis example 2≫ An example of a method for synthesizing the low refractive index electron transport material described in the first embodiment will be shown below.

[0334] First, we will explain the synthesis method of 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3,5-triazine (abbreviation: mmtBumBP-dmmtBuPTzn), an organic compound represented by structural formula (200). The structure of mmtBumBP-dmmtBuPTzn is shown below.

[0335] [ka]

[0336] <Step 1: Synthesis of 3-bromo-3',5'-di-tert-butylbiphenyl> A three-neck flask was charged with 1.0 g (4.3 mmol) of 3,5-di-tert-butylphenylboronic acid, 1.5 g (5.2 mmol) of 1-bromo-3-iodobenzene, 4.5 mL of 2 mol / L aqueous potassium carbonate, 20 mL of toluene, and 3 mL of ethanol. The mixture was degassed by stirring under reduced pressure. 52 mg (0.17 mmol) of tris(2-methylphenyl)phosphine (abbreviated as P(o-tplyl)3) and 10 mg (0.043 mmol) of palladium(II) acetate (abbreviated as Pd(OAc)2) were added and reacted at 80 °C for 14 hours under a nitrogen atmosphere. After completion of the reaction, the mixture was extracted with toluene, and the resulting organic layer was dried over magnesium sulfate. The mixture was gravity filtered, and the filtrate was purified by silica gel column chromatography (eluent: hexane) to obtain 1.0 g of the desired white solid (yield: 68%). The synthesis scheme for Step 1 is shown below.

[0337] [ka]

[0338] Step 2: Synthesis of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane A three-neck flask was charged with 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. The mixture was degassed by stirring under reduced pressure. To this mixture were added 0.12 g (0.30 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (SPhos) and 0.12 g (0.15 mmol) of [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride dichloromethane adduct (Pd(dppf)2Cl2·CHCl2) and reacted for 24 hours at 110°C under a nitrogen atmosphere. After the reaction was complete, the mixture was extracted with toluene, and the resulting organic layer was dried over magnesium sulfate. The mixture was gravity filtered. 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.

[0339] [ka]

[0340] <Step 3: Synthesis of mmtBumBP-dmmtBuPTzn> A three-neck flask was charged with 0.8 g (1.6 mmol) of 4,6-bis(3,5-di-tert-butylphenyl)-2-chloro-1,3,5-triazine, 0.89 g (2.3 mmol) of 2-(3',5'-di-tert-butylbiphenyl-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 0.68 g (3.2 mmol) of tripotassium phosphate, 3 mL of water, 8 mL of toluene, and 3 mL of 1,4-dioxane. The mixture was degassed by stirring under reduced pressure. 3.5 mg (0.016 mmol) of palladium(II) acetate and 10 mg (0.032 mmol) of tris(2-methylphenyl)phosphine were added and heated to reflux under a nitrogen atmosphere for 12 hours. After completion of the reaction, the mixture was extracted with ethyl acetate, and the resulting organic layer was dried over magnesium sulfate. The mixture was gravity filtered. The resulting filtrate was concentrated and purified by silica gel column chromatography (eluent: ethyl acetate:hexane = 1:20) to obtain a solid. This solid was purified by silica gel column chromatography (eluent: chloroform:hexane = 5:1 changed to 1:0). The resulting solid was recrystallized with hexane to obtain 0.88 g (yield: 76%) of the desired white solid. The synthesis scheme for Step 3 is shown below.

[0341] [ka]

[0342] 0.87 g of the obtained white solid was purified by train sublimation at 230° C. under a pressure of 5.8 Pa and a flow of argon gas. After sublimation purification, 0.82 g of the target white solid was obtained with a recovery rate of 95%.

[0343] The white solid obtained in step 3 was analyzed by nuclear magnetic resonance spectroscopy ( 1 The results of the analysis by H-NMR are shown below. From these results, it was found that mmtBumBP-dmmtBuPTzn represented by the above structural formula (200) was obtained by the above synthesis method.

[0344] 1H NMR (CDCl3, 300MHz): δ=1.42-1.49(m,54H),7.50(s,1H),7.61-7.70(m,5H),7.87(d,1H),8.68-8.69(m,4H),8.78(d,1H),9.06(s,1H).

[0345] Figure 15 shows the refractive index of mmtBumBP-dmmtBuPTzn obtained by the synthesis method described above, measured using a spectroscopic ellipsometer (M-2000U manufactured by J.A. Woollam Japan). For the measurements, films of approximately 50 nm thickness were formed on a quartz substrate using vacuum deposition of the materials for each layer. The figure also shows the refractive index for ordinary rays, n Ordinary, and the refractive index for extraordinary rays, n Extraordinary.

[0346] This figure shows that mmtBumBP-dmmtBuPTzn has an ordinary refractive index in the range of 1.50 to 1.75 throughout the entire blue emission region (455 nm to 465 nm), and that the ordinary refractive index at 633 nm is also in the range of 1.45 to 1.70, making it a low refractive index material.

[0347] Similarly, organic compounds represented by the following structural formulas (201) to (204) were synthesized.

[0348] [ka]

[0349] In addition, the nuclear magnetic resonance spectroscopy ( 1 The results of analysis by H-NMR are shown below.

[0350] Structural formula (201) 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumBPTzn) 1H NMR (CDCl3, 300MHz): 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).

[0351] Structural formula (202) 2-(3,3'',5,5''-tetra-tert-butyl-1,1':3',1''-phenyl-5'-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumTPTzn) 1 H NMR (CDCl3, 300MHz): δ = 1.44 (s, 36H), 7.54-7.62 (m, 12H), 7.99 (t, 1H), 8.79 (d, 4H), 8.92 (d, 2H).

[0352] Structural formula (203) 2-{(3',5'-di-tert-butyl)-1,1'-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3-pyrimidine (abbreviation: mmtBumBP-dmmtBuPPm) 1 H NMR (CDCl3,300MHz): δ=1.39-1.45(m,54H),7.47(t,1H),7.59-7.65(m,5H),7.76(d,1H),7.95(s,1H),8.06(d,4H),8.73(d,1H,8.99(s,1H)).

[0353] Structural formula (204) 2-(3,3'',5',5''-tetra-tert-butyl-1,1':3',1''-terphenyl-5-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumTPTzn-02) 1 H NMR(CDCl3,300MHz):δ=1.41(s,18H),1.49(s,9H),1.52(s,9H),7.49(s,3 H),7.58-7.63(m,7H),7.69-7.70(m,2H),7.88(t,1H),8.77-8.83(m,6H).

[0354] All of the above organic compounds have an ordinary refractive index of 1.50 or more and 1.75 or less in the blue light emission region (455 nm or more and 465 nm or less), or an ordinary refractive index of 1.45 or more and 1.70 or less in the 633 nm light wavelength that is typically used to measure refractive index. [Explanation of symbols]

[0355] 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, 400: substrate, 401: anode, 403: EL layer, 404: cathode, 405: sealing material, 406: sealing material, 407: sealing 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: sealing substrate, 605: 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: base insulating film, 1003: gate insulating film, 1006: gate electrode, 1007: gate electrode, 1008: gate electrode, 1020: first interlayer insulating film, 1021: second 2 interlayer insulating film, 1022: electrode, 1024W: anode, 1024R: anode, 1024G: anode, 1024B: anode, 1025: partition wall, 1028: EL layer, 1029: cathode, 1031: sealing substrate, 1032: sealing material, 1033: transparent base material, 1034R: red colored layer, 1034G: green colored layer, 1034B: blue colored layer, 1035: black matrix, 1036: overcoat layer, 1037: third interlayer insulating film, 1040: pixel section, 1041: drive circuit section, 1042: peripheral section, 2001: housing, 2002: light source, 2100: robot, 2110: Calculation device, 2101: illuminance sensor, 2102: microphone, 2103: upper camera, 2104: speaker, 2105: display, 2106: lower camera, 2107: obstacle sensor, 2108: movement mechanism, 3001: lighting device, 5000: housing, 5001: display unit, 5002: second display unit, 5003: speaker, 5004: LED lamp, 5005: operation key, 5006: connection terminal, 5007: sensor, 5008: microphone, 5012: support unit, 5013: earphone, 5100: cleaning robot, 5101: display, 5102: camera,5103: Brush, 5104: Operation button, 5150: Mobile 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 unit, 7105: Stand, 7107: Display unit, 7109: Operation key, 7110: Remote control unit, 7201: Main unit, 72 02: Housing, 7203: Display unit, 7204: Keyboard, 7205: External connection port, 7206: Pointing device, 7210: Display unit, 7401: Housing, 7402: Display unit, 7403: Operation buttons, 7404: External connection port, 7405: Speaker, 7406: Microphone, 7400: Mobile phone, 9310: Portable information terminal, 9311: Display panel, 9313: Hinge, 9315: Housing,

Claims

1. an anode; A cathode; a hole transport region, a light emitting layer, and an electron transport region between the anode and the cathode; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; the hole transport region includes any one of a sulfonic acid compound, a fluorine compound, and a metal oxide; the electron transport region includes an organic compound having electron transport properties, the ratio of the number of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound having electron transport properties is 10% or more and 60% or less, The organic compound having electron transport properties has an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less.

2. an anode; A cathode; a hole transport region, a light emitting layer, and an electron transport region between the anode and the cathode; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; the hole transport region includes any one of a sulfonic acid compound, a fluorine compound, and a metal oxide; the electron transport region includes an organic compound having electron transport properties, the ratio of the number of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound having electron transport properties is 10% or more and 60% or less, The organic compound having electron transport properties has an ordinary refractive index of 1.45 or more and 1.70 or less for light having a wavelength of 633 nm.

3. an anode; A cathode; a hole transport region, a light emitting layer, and an electron transport region between the anode and the cathode; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; When the hole transport region is measured by ToF-SIMS, a signal is detected around m / z=80 in the negative mode measurement results, the electron transport region includes an organic compound having electron transport properties, the ratio of the number of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound having electron transport properties is 10% or more and 60% or less, a light-emitting device in which the organic compound having electron transport properties has an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less;

4. an anode; A cathode; a hole transport region, a light emitting layer, and an electron transport region between the anode and the cathode; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; When the hole transport region is measured by ToF-SIMS in a negative mode, the hole transport region has a signal at about m / z=80; the electron transport region includes an organic compound having electron transport properties, the ratio of the number of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound having electron transport properties is 10% or more and 60% or less, The organic compound having electron transport properties has an ordinary refractive index of 1.45 or more and 1.70 or less for light having a wavelength of 633 nm.

5. In claim 3 or claim 4, The hole transport region is a light-emitting device in which signals are detected around m / z=80 and m / z=901 in negative mode measurement by ToF-SIMS.

6. an anode; A cathode; a hole transport region, a light emitting layer, and an electron transport region between the anode and the cathode; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; When the hole transport region was subjected to MS analysis, a signal was detected around m / z=80 in the negative mode measurement results, the electron transport region includes an organic compound having electron transport properties, the ratio of the number of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound having electron transport properties is 10% or more and 60% or less, a light-emitting device in which the organic compound having electron transport properties has an ordinary refractive index of 1.50 or more and 1.75 or less for light with a wavelength of 455 nm or more and 465 nm or less;

7. an anode; A cathode; a hole transport region, a light emitting layer, and an electron transport region between the anode and the cathode; the hole transport region is located between the anode and the light-emitting layer; the electron transport region is located between the cathode and the light-emitting layer; When MS analysis is performed, the hole transport region has a signal at m / z=80 in the negative mode measurement result, the electron transport region includes an organic compound having electron transport properties, the ratio of the number of carbon atoms forming bonds via sp3 hybrid orbitals to the total number of carbon atoms in the molecule of the organic compound having electron transport properties is 10% or more and 60% or less, The organic compound having electron transport properties has an ordinary refractive index of 1.45 or more and 1.70 or less for light having a wavelength of 633 nm.

8. In claim 6 or claim 7, The light-emitting device in which, when MS analysis is performed, the hole transport region detects a signal in a mass range of ±2.0 to 241, 161, or 81 less than that of the target ion in negative mode.

9. In any one of claims 1 to 8, The hole transport region is a light-emitting device in which a g value of the hole transport region has a signal in the vicinity of about 2.00 when measured by an electron spin resonance spectrum using an ESR method.

10. A light emitting device comprising a plurality of light emitting devices according to any one of claims 1 to 9.

11. A light-emitting device according to any one of claims 1 to 9, the plurality of light-emitting devices include at least a light-emitting device that emits red light and a light-emitting device that emits green light; the light-emitting layer of the red-emitting light-emitting device comprises a first phosphorescent light-emitting material; The light-emitting layer of the green-emitting light-emitting device comprises a second phosphorescent light-emitting material.

12. In claim 10 or claim 11, the plurality of light-emitting devices further includes a light-emitting device that emits blue light; The light-emitting device, wherein the light-emitting layer of the blue-emitting light-emitting device comprises a fluorescent material.

13. A display device comprising the light-emitting device according to any one of claims 10 to 12.

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