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

Abstract

To provide a light emitting device that emits near-infrared light and has high luminous efficiency and reliability.SOLUTION: A light emitting device emits light with a maximum peak wavelength of 760 nm or more and 900 nm or less, and has an organometallic complex represented by the general formula (G1) in a light emitting layer.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One embodiment of the present invention relates to a light-emitting device, a light-emitting apparatus, a light-emitting module, an electronic device, a lighting apparatus, an organometallic complex, a light-emitting material, an organic compound, and a polynuclear complex, each of which emits near-infrared light.

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), a driving method thereof, or a manufacturing method thereof. [Background technology]

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

[0004] Examples of light-emitting organic compounds include compounds that can convert a triplet excited state into light emission (also called phosphorescent compounds or phosphorescent materials). Patent Document 1 discloses an organometallic complex having iridium or the like as a central metal as a phosphorescent material.

[0005] Image sensors are also used for various purposes, such as personal authentication, defect analysis, medical diagnosis, and security. Image sensors use different wavelengths of light source depending on the purpose. Image sensors use light of various wavelengths, for example, visible light, short wavelength light such as X-rays, and long wavelength light such as near-infrared light.

[0006] In addition to applications as display devices, applications of light-emitting devices as light sources for the above-mentioned image sensors are also being considered. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2007-137872 A Summary of the Invention [Problem to be solved by the invention]

[0008] An object of one embodiment of the present invention is to improve the emission efficiency of a light-emitting device that emits near-infrared light.An object of one embodiment of the present invention is to improve the reliability of a light-emitting device that emits near-infrared light.An object of one embodiment of the present invention is to extend the lifetime of a light-emitting device that emits near-infrared light.

[0009] An object of one embodiment of the present invention is to provide an organometallic complex with high emission efficiency.An object of one embodiment of the present invention is to provide an organometallic complex with high chemical stability.An object of one embodiment of the present invention is to provide a novel organometallic complex that emits near-infrared light.An object of one embodiment of the present invention is to provide a novel organometallic complex that can be used for an EL layer of a light-emitting device.

[0010] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description of the specification, drawings, and claims. [Means for solving the problem]

[0011] One embodiment of the present invention is a light-emitting device (also referred to as a light-emitting element) having a light-emitting layer. The light-emitting layer contains a light-emitting organic compound. The maximum peak wavelength (also referred to as the wavelength with the highest peak intensity) of light emitted by the light-emitting organic compound is 760 nm or more and 900 nm or less.

[0012] One embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, and a light-emitting layer. The light-emitting layer is located between the first electrode and the second electrode. The light-emitting layer contains a light-emitting organic compound. The maximum peak wavelength of light emitted by the light-emitting organic compound is 760 nm or more and 900 nm or less.

[0013] The maximum peak wavelength of the light emitted by the light-emitting organic compound is preferably 780 nm or more, and the maximum peak wavelength of the light emitted by the light-emitting organic compound is preferably 880 nm or less.

[0014] The luminescent organic compound is preferably an organometallic complex having a metal-carbon bond. Among them, the luminescent organic compound is more preferably a cyclometal complex. The luminescent organic compound is preferably an orthometal complex. The luminescent organic compound is preferably an iridium complex. When the luminescent organic compound is an organometallic complex having a metal-carbon bond, the organometallic complex preferably has 2 to 5 condensed heteroaromatic rings, and the condensed heteroaromatic rings are preferably coordinated to a metal. The condensed heteroaromatic rings preferably have 3 or more rings. The condensed heteroaromatic rings preferably have 4 or less rings.

[0015] One embodiment of the present invention is a light-emitting device including a light-emitting device having any of the above structures and one or both of a transistor and a substrate.

[0016] One embodiment of the present invention is a light-emitting module having the above-mentioned light-emitting device, such as a module to which a connector such as a flexible printed circuit (hereinafter, referred to as FPC) or a TCP (Tape Carrier Package) is attached, or a light-emitting module to which an integrated circuit (IC) is mounted by a COG (Chip On Glass) method or a COF (Chip On Film) method, etc. Note that the light-emitting module of one embodiment of the present invention may have only one of a connector and an IC, or may have both.

[0017] One embodiment of the present invention is an electronic device including the above-described light-emitting module and at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

[0018] One embodiment of the present invention is a lighting device including the above-described light-emitting device and at least one of a housing, a cover, and a support base.

[0019] One embodiment of the present invention is an organometallic complex represented by General Formula (G1). Another embodiment of the present invention is a light-emitting material represented by General Formula (G1). Another embodiment of the present invention is a material for a light-emitting device represented by General Formula (G1).

[0020] [ka]

[0021] In general formula (G1), R 1 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9 At least two of the above represent an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, n is 2 or 3, and L represents a monoanionic ligand.

[0022] One embodiment of the present invention is an organometallic complex represented by General Formula (G2). Another embodiment of the present invention is a light-emitting material represented by General Formula (G2). Another embodiment of the present invention is a material for a light-emitting device represented by General Formula (G2).

[0023] [ka]

[0024] In general formula (G2), R 1 , R 3 , R 6 , and R 8 each independently represents an alkyl group having 1 to 6 carbon atoms; R 10 and R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, n is 2 or 3, and L represents a monoanionic ligand.

[0025] The maximum peak wavelength of light emitted from the organometallic complex, the light-emitting material, or the material for a light-emitting device according to one embodiment of the present invention is preferably 760 nm or more and 900 nm or less.

[0026] One embodiment of the present invention is a light-emitting device having a light-emitting layer. The light-emitting layer includes any of the above-described organometallic complexes, light-emitting materials, or materials for light-emitting devices. The light-emitting device has a function of emitting light having a maximum peak wavelength of 760 nm to 900 nm.

[0027] One embodiment of the present invention is an organic compound represented by general formula (G0).

[0028] [ka]

[0029] In general formula (G0), R 1 ~R 11each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9 At least two of the above represent an alkyl group having 1 to 6 carbon atoms, and X represents a substituted or unsubstituted benzene ring or naphthalene ring.

[0030] One embodiment of the present invention is an organic compound represented by structural formula (200).

[0031] [ka]

[0032] One embodiment of the present invention is a dinuclear complex represented by general formula (B).

[0033] [ka]

[0034] In the general formula (B), Z represents a halogen, R 1 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9 At least two of the above represent an alkyl group having 1 to 6 carbon atoms, and X represents a substituted or unsubstituted benzene ring or naphthalene ring.

[0035] One embodiment of the present invention is a dinuclear complex represented by structural formula (210).

[0036] [ka] Effect of the Invention

[0037] According to one embodiment of the present invention, the light-emitting efficiency of a light-emitting device that emits near-infrared light can be improved. According to one embodiment of the present invention, the reliability of a light-emitting device that emits near-infrared light can be improved. According to one embodiment of the present invention, the lifetime of a light-emitting device that emits near-infrared light can be extended.

[0038] According to one embodiment of the present invention, an organometallic complex with high emission efficiency can be provided. According to one embodiment of the present invention, an organometallic complex with high chemical stability can be provided. According to one embodiment of the present invention, a novel organometallic complex that emits near-infrared light can be provided. According to one embodiment of the present invention, a novel organometallic complex that can be used for an EL layer of a light-emitting device can be provided.

[0039] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims. [Brief description of the drawings]

[0040] [Figure 1] 1A, 1B, and 1C are cross-sectional views showing an example of a light-emitting device. [Diagram 2] Fig. 2A is a top view showing an example of a light emitting device, and Fig. 2B and Fig. 2C are cross-sectional views showing an example of the light emitting device. [Diagram 3] Fig. 3A is a top view showing an example of a light emitting device, and Fig. 3B is a cross-sectional view showing an example of the light emitting device. [Figure 4] 4A to 4E are diagrams showing an example of an electronic device. [Diagram 5] FIG. 5 is a 1H-NMR chart of the organic compound represented by the structural formula (200). [Figure 6] FIG. 6 is a 1H-NMR chart of the organometallic complex shown in structural formula (100). [Figure 7] FIG. 7 shows the ultraviolet-visible absorption spectrum and emission spectrum of the organometallic complex represented by the structural formula (100). [Figure 8]FIG. 8 is a graph showing the weight change rate of the organometallic complex represented by the structural formula (100). [Figure 9] 9A and 9B are cross-sectional views showing a light-emitting device according to an embodiment. [Figure 10] FIG. 10 is a graph showing the current density-radiant emittance characteristics of the light-emitting device 1. As shown in FIG. [Figure 11] FIG. 11 is a graph showing the voltage-current density characteristics of the light-emitting device 1. As shown in FIG. [Figure 12] FIG. 12 is a graph showing the current density-radiant flux characteristics of the light-emitting device 1. As shown in FIG. [Figure 13] FIG. 13 is a graph showing the voltage-radiant emittance characteristics of the light-emitting device 1. As shown in FIG. [Figure 14] FIG. 14 is a graph showing the current density-external quantum efficiency characteristics of the light-emitting device 1. As shown in FIG. [Figure 15] FIG. 15 is a diagram showing the emission spectrum of the light-emitting device 1. As shown in FIG. [Figure 16] FIG. 16 is a diagram showing the results of a reliability test of the light emitting device 1. As shown in FIG. [Figure 17] FIG. 17 is a graph showing the current density-radiant emittance characteristics of the light-emitting device 2. As shown in FIG. [Figure 18] FIG. 18 is a graph showing the voltage-current density characteristics of the light-emitting device 2. As shown in FIG. [Figure 19] FIG. 19 is a graph showing the current density-radiant flux characteristics of the light-emitting device 2. As shown in FIG. [Figure 20] FIG. 20 is a graph showing the voltage-radiant emittance characteristics of the light-emitting device 2. As shown in FIG. [Figure 21] FIG. 21 is a graph showing the current density-external quantum efficiency characteristics of the light-emitting device 2. As shown in FIG. [Figure 22] FIG. 22 is a diagram showing the emission spectrum of the light-emitting device 2. As shown in FIG. [Figure 23] FIG. 23 shows the results of a reliability test of the light emitting device 2. As shown in FIG. [Figure 24] FIG. 24 is a graph showing the current density-radiant emittance characteristics of the light-emitting device 3. As shown in FIG. [Diagram 25] FIG. 25 is a graph showing the voltage-current density characteristics of the light-emitting device 3. As shown in FIG. [Figure 26] FIG. 26 is a graph showing the current density-radiant flux characteristics of the light-emitting device 3. As shown in FIG. [Figure 27] FIG. 27 is a graph showing the voltage-radiant emittance characteristics of the light-emitting device 3. As shown in FIG. [Figure 28] FIG. 28 is a graph showing the current density-external quantum efficiency characteristics of the light-emitting device 3. As shown in FIG. [Figure 29] FIG. 29 is a graph showing the emission spectrum of the light-emitting device 3. As shown in FIG. [Diagram 30] FIG. 30 shows the results of a reliability test on the light emitting device 3. As shown in FIG. [Diagram 31] FIG. 31 is a graph showing the angle dependence of the relative intensity of the light emitting device 3. As shown in FIG. [Diagram 32] FIG. 32 is a graph showing the angle dependence of the normalized photon intensity of the light-emitting device 3. As shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] The embodiments 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 easily understood by those skilled in the art that the modes and details of the present invention can be modified in various ways 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.

[0042] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and the repeated explanations are omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be used.

[0043] In addition, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0044] In addition, the words "film" and "layer" can be interchanged depending on the case or situation. For example, the term "conductive layer" can be changed to the term "conductive film". Or, for example, the term "insulating film" can be changed to the term "insulating layer".

[0045] (Embodiment 1) In this embodiment, an organometallic complex of one embodiment of the present invention will be described.

[0046] [Structure of an organometallic complex according to one embodiment of the present invention] An organometallic complex of one embodiment of the present invention has a structure in which a ligand having a benzoquinoxaline skeleton or a naphthoquinoxaline skeleton is coordinated to iridium, which is a central metal. Specifically, one embodiment of the present invention is an organometallic complex represented by General Formula (G1). Another embodiment of the present invention is a light-emitting material represented by General Formula (G1). Another embodiment of the present invention is a material for a light-emitting device represented by General Formula (G1).

[0047] [ka]

[0048] In general formula (G1), R 1 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9 At least two of the above represent an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, n is 2 or 3, and L represents a monoanionic ligand.

[0049] In the general formula (G1), X is a substituted or unsubstituted benzene ring or naphthalene ring, that is, by condensing a benzene ring or a naphthalene ring to quinoxaline, the π-conjugated system is extended, the lowest unoccupied molecular orbital (LUMO) level is deepened, and the energy can be stabilized, so that the emission wavelength can be made longer. Therefore, an organometallic complex that emits near-infrared light can be obtained.

[0050] One embodiment of the present invention is an organometallic complex represented by General Formula (G2). Another embodiment of the present invention is a light-emitting material represented by General Formula (G2). Another embodiment of the present invention is a material for a light-emitting device represented by General Formula (G2).

[0051] [ka]

[0052] In general formula (G2), R 1 , R 3 , R 6 , and R 8 each independently represents an alkyl group having 1 to 6 carbon atoms; R 10 and R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, n is 2 or 3, and L represents a monoanionic ligand.

[0053] In general formula (G2), X is a substituted or unsubstituted benzene ring or naphthalene ring, that is, by condensing a benzene ring or naphthalene ring to quinoxaline, the π-conjugated system can be extended, the LUMO level can be deepened, and the energy can be stabilized, so that the emission wavelength can be made longer. Therefore, an organometallic complex that emits near-infrared light can be obtained.

[0054] R 1 , R 3 , R 6 , and R 8 is an alkyl group having 1 to 6 carbon atoms, R1 , R 3 , R 6 , and R 8 is hydrogen, the sublimability of the organometallic complex is increased, and the sublimation temperature can be lowered, which is preferable. 1 , R 3 , R 6 , and R 8 Each of R is preferably a methyl group. 1 , R 3 , R 6 , and R 8 It is preferable that each of these is a methyl group.

[0055] In one embodiment of the present invention, X is a substituted or unsubstituted benzene ring or naphthalene ring, and the sublimability of the organometallic complex tends to be lower than when X is not a fused ring. 1 , R 3 , R 6 , and R 8 However, since the alkyl group has 1 to 6 carbon atoms, the sublimability of the organometallic complex can be improved. Therefore, it is possible to obtain an organometallic complex that has good sublimability and emits near-infrared light.

[0056] R 1 and R 3 However, by using an alkyl group having 1 to 6 carbon atoms, the dihedral angle of the benzene ring bonded to iridium can be increased. This theoretically makes it possible to reduce the second peak of the emission spectrum of the organometallic complex, narrowing the half-width. This makes it possible to efficiently obtain light of the desired wavelength.

[0057] In general formulae (G1) and (G2), examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group.

[0058] In the general formula (G1) and the general formula (G2), when the benzene ring or the naphthalene ring has a substituent, the substituent can be an alkyl group having from 1 to 6 carbon atoms. The above description can be applied to the alkyl group having from 1 to 6 carbon atoms.

[0059] Examples of the monoanionic ligand include a monoanionic bidentate chelate ligand having a β-diketone structure, a monoanionic bidentate chelate ligand having a carboxyl group, a monoanionic bidentate chelate ligand having a phenolic hydroxyl group, a monoanionic bidentate chelate ligand in which both of the coordinating elements are nitrogen, and a bidentate ligand that forms a metal-carbon bond with iridium by cyclometallation.

[0060] The monoanionic ligand is preferably any one of the general formulae (L1) to (L7). In particular, the use of the ligand represented by the general formula (L1) is preferable because the sublimability is increased. In addition, the combination of the ligand represented by the structural formula (L8) (dipivaloylmethane), which is an example of the ligand represented by the general formula (L1), and a ligand having a benzoquinoxaline skeleton or a naphthoquinoxaline skeleton is preferable because the sublimability of the organometallic complex of one embodiment of the present invention is increased and the sublimation temperature can be reduced.

[0061] [ka]

[0062] In general formulas (L1) to (L7), R 51~R 89 each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogeno group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; A 1 ~A 13 are independently sp bonds to nitrogen and hydrogen. 2 Hybridized carbon or substituted sp 2 It represents a hybrid carbon, and the substituent is any one of an alkyl group having 1 to 6 carbon atoms, a halogeno group, a haloalkyl group having 1 to 6 carbon atoms, or a phenyl group.

[0063] The maximum peak wavelength (i.e., the wavelength with the highest peak intensity) of light emitted by the organometallic complex according to one embodiment of the present invention is preferably 760 nm or more and 900 nm or less. In particular, the wavelength is preferably 780 nm or more. Moreover, the wavelength is preferably 880 nm or less.

[0064] Specific examples of the organometallic complex of one embodiment of the present invention include organometallic complexes represented by structural formulas (100) to (111). However, the present invention is not limited thereto.

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [Method for synthesizing an organometallic complex according to one embodiment of the present invention] Various reactions can be applied as a method for synthesizing the organometallic complex of one embodiment of the present invention. A method for synthesizing the organometallic complex represented by General Formula (G1) will be exemplified below.

[0070] First, an example of a method for synthesizing an organic compound represented by General Formula (G0) will be described, and then a method for synthesizing an organometallic complex represented by General Formula (G1) using the organic compound represented by General Formula (G0) will be described. Note that the following description will be divided into a case where n in General Formula (G1) is 2 (an organometallic complex represented by General Formula (G1-1)) and a case where n in General Formula (G1) is 3 (an organometallic complex represented by General Formula (G1-2)). Note that the method for synthesizing an organometallic complex of one embodiment of the present invention is not limited to the following synthesis method.

[0071] <Example of a method for synthesizing an organic compound represented by general formula (G0)> The organic compound represented by General Formula (G0) is a type of quinoxaline derivative and is an organic compound according to one embodiment of the present invention. The organic compound represented by General Formula (G0) can be synthesized, for example, by using any one of the three synthetic schemes (A-1), (A-1'), and (A-1'') shown below.

[0072] [ka]

[0073] In the general formula (G0) and the synthesis schemes (A-1), (A-1′), and (A-1″) described below, R 1 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9At least two of the above represent an alkyl group having 1 to 6 carbon atoms, and X represents a substituted or unsubstituted benzene ring or naphthalene ring.

[0074] For example, the organic compound represented by the general formula (G0) can be obtained by lithiating a halogenated benzene derivative (A1) with an alkyl lithium or the like and reacting the lithiated derivative with a quinoxaline derivative (A2) as shown in the synthetic scheme (A-1). 1 represents a halogen.

[0075] [ka]

[0076] In addition, the organic compound represented by the general formula (G0) can be obtained by coupling a benzene derivative boronic acid (A1') with a quinoxaline halide (A2') as shown in the synthetic scheme (A-1'). In the synthetic scheme (A-1'), Z 2 represents a halogen.

[0077] [ka]

[0078] In addition, the organic compound represented by general formula (G0) can be obtained by reacting a benzene derivative-substituted diketone (A1'') with a diamine (A2'') as shown in the synthesis scheme (A-1'').

[0079] [ka]

[0080] The synthesis method for the organic compound represented by general formula (G0) is not limited to the above-mentioned three synthesis methods, and other synthesis methods may be used.

[0081] Various types of the above-mentioned compounds (A1), (A2), (A1'), (A2'), (A1"), and (A2") are commercially available or can be synthesized, and therefore many types of organic compounds represented by general formula (G0) can be synthesized. Thus, the organometallic complex of one embodiment of the present invention is characterized by a wide variety of ligands.

[0082] <Method for synthesizing organometallic complex represented by general formula (G1-1)> Next, an example of a method for synthesizing an organometallic complex represented by General Formula (G1-1) will be described. The organometallic complex represented by General Formula (G1-1) is an organometallic complex according to one embodiment of the present invention, and corresponds to the case where n in General Formula (G1) is 2.

[0083] [ka]

[0084] In the general formula (G1-1) and the synthetic schemes (A-2) and (A-3) described below, R 1 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9 At least two of the above represent an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, and L represents a monoanionic ligand.

[0085] First, as shown in the synthesis scheme (A-2), an organic compound represented by the general formula (G0) and an iridium compound containing a halogen (iridium chloride, iridium bromide, iridium iodide, etc.) are heated in an inert gas atmosphere using no solvent, an alcohol-based solvent (glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.) alone, or a mixed solvent of one or more alcohol-based solvents and water, to obtain a binuclear complex represented by the general formula (B). There is no particular limitation on the heating means, and an oil bath, a sand bath, or an aluminum block may be used. Microwaves may also be used as a heating means.

[0086] The dinuclear complex represented by general formula (B) is a type of organometallic complex having a structure bridged with halogen, and is a dinuclear complex according to one embodiment of the present invention.

[0087] [ka]

[0088] Furthermore, as shown in the synthesis scheme (A-3), by reacting the binuclear complex represented by the general formula (B) with the raw material HL of the monoanionic ligand in an inert gas atmosphere, the proton of HL is eliminated and L is coordinated to the central metal (Ir), thereby obtaining the organometallic complex represented by the general formula (G1-1). There is no particular limitation on the heating means, and an oil bath, a sand bath, or an aluminum block may be used. Microwaves may also be used as the heating means.

[0089] [ka]

[0090] In the synthetic schemes (A-2) and (A-3), Z represents a halogen.

[0091] <Method for synthesizing organometallic complex represented by general formula (G1-2)> Next, an example of a method for synthesizing an organometallic complex represented by General Formula (G1-2) will be described. The organometallic complex represented by General Formula (G1-2) is an organometallic complex according to one embodiment of the present invention, and corresponds to the case where n in General Formula (G1) is 3.

[0092] [ka]

[0093] In the general formula (G1-2) and the synthetic scheme (A-4) described later, R 1 ~R 11 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent an alkyl group having 1 to 6 carbon atoms. 5 ~R 9 At least two of the above represent an alkyl group having 1 to 6 carbon atoms, and X represents a substituted or unsubstituted benzene ring or naphthalene ring.

[0094] As shown in the synthesis scheme (A-4), the organometallic complex represented by the general formula (G1-2) can be obtained by mixing a halogen-containing iridium compound (iridium chloride hydrate, iridium bromide, iridium iodide, iridium acetate, ammonium hexachloroiridate, etc.) or an organic iridium complex (acetylacetonato complex, diethylsulfide complex, di-μ-chloro bridged binuclear complex, di-μ-hydroxo bridged binuclear complex, etc.) with an organic compound represented by the general formula (G0), dissolving the mixture in a solventless manner or in an alcohol solvent (glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.), and then heating the mixture.

[0095] [ka]

[0096] Although the synthesis method of the organometallic complex of one embodiment of the present invention has been described above, the present invention is not limited thereto, and the organometallic complex may be synthesized by another synthesis method.

[0097] As described above, the organometallic complex of one embodiment of the present invention emits near-infrared light and has high sublimability, and is therefore suitable as a light-emitting material that emits near-infrared light or a material for a light-emitting device. By using the organometallic complex of one embodiment of the present invention, the emission efficiency of a light-emitting device that emits near-infrared light can be increased. In addition, by using the organometallic complex of one embodiment of the present invention, the reliability of a light-emitting device that emits near-infrared light can be increased.

[0098] This embodiment mode can be combined with other embodiment modes as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate.

[0099] (Embodiment 2) In this embodiment, a light-emitting device according to one embodiment of the present invention and a light-emitting device according to one embodiment of the present invention will be described with reference to FIGS.

[0100] The light-emitting device according to one embodiment of the present invention includes a light-emitting organic compound in a light-emitting layer, and the maximum peak wavelength (which can also be referred to as the wavelength with the highest peak intensity) of light emitted from the light-emitting organic compound is 760 nm or more and 900 nm or less, preferably 780 nm or more, and preferably 880 nm or less.

[0101] The light-emitting device of one embodiment of the present invention can be formed into a film and can be easily increased in area; therefore, the light-emitting device can be used as a surface light source that emits near-infrared light.

[0102] A light-emitting organic compound is preferable because it can increase the light-emitting efficiency of a light-emitting device when it emits phosphorescence. In particular, the light-emitting organic compound is preferably an organometallic complex having a metal-carbon bond. Among them, the light-emitting organic compound is more preferably a cyclometal complex. Furthermore, the light-emitting organic compound is preferably an orthometal complex. These organic compounds are easy to emit phosphorescence, so that the light-emitting efficiency of a light-emitting device can be increased. Therefore, the light-emitting device of one embodiment of the present invention is preferably a phosphorescent device that emits phosphorescence.

[0103] Furthermore, organometallic complexes having a metal-carbon bond have higher luminous efficiency and higher chemical stability than porphyrin-based compounds, and are therefore suitable as luminescent organic compounds.

[0104] In addition, when a light-emitting organic compound is used as a guest material in the light-emitting layer and another organic compound is used as a host material, if a large valley occurs in the absorption spectrum of the light-emitting organic compound (a low-intensity portion occurs), depending on the value of the excitation energy of the host material, the energy transfer from the host material to the guest material does not proceed smoothly, and the energy transfer efficiency decreases. Here, in the absorption spectrum of an organometallic complex having a metal-carbon bond, many absorption bands overlap, such as an absorption band derived from a triplet MLCT (Metal to Ligand Charge Transfer) transition, an absorption band derived from a singlet MLCT transition, and an absorption band derived from a triplet π-π* transition, so that a large valley is unlikely to occur in the absorption spectrum. Therefore, the range of excitation energy values ​​of materials that can be used as a host material can be widened, and the range of host materials to be selected can be expanded.

[0105] In addition, the light-emitting organic compound is preferably an iridium complex. For example, the light-emitting organic compound is preferably a cyclometal complex using iridium as the central metal. Since the iridium complex has higher chemical stability than platinum complexes, the reliability of the light-emitting device can be improved by using an iridium complex as the light-emitting organic compound. From the viewpoint of such stability, a cyclometal complex of iridium is preferable, and an orthometal complex of iridium is more preferable.

[0106] In addition, from the viewpoint of obtaining near-infrared emission, the ligand in the above-mentioned organometallic complex preferably has a structure in which a fused heteroaromatic ring having 2 to 5 rings is coordinated to a metal. The fused heteroaromatic ring preferably has 3 or more rings. In addition, the fused heteroaromatic ring preferably has 4 or less rings. The more rings the fused heteroaromatic ring has, the lower the LUMO level can be, and the longer the emission wavelength of the organometallic complex can be. In addition, the fewer the fused heteroaromatic rings, the higher the sublimability can be. Therefore, by adopting a fused heteroaromatic ring having 2 to 5 rings, the LUMO level of the ligand is appropriately lowered, and the emission wavelength of the organometallic complex derived from the (triplet) MLCT transition can be extended to the near infrared while maintaining high sublimability. In addition, the more the number of nitrogen atoms (N) the fused heteroaromatic ring has, the lower the LUMO level can be. Therefore, the number of nitrogen atoms (N) in the condensed heteroaromatic ring is preferably two or more, and particularly preferably two.

[0107] [Example of light-emitting device configuration] <Basic structure of light-emitting devices> 1A to 1C show an example of a light-emitting device having an EL layer between a pair of electrodes.

[0108] 1A has a structure (single structure) in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102. The EL layer 103 has at least a light-emitting layer.

[0109] The light-emitting device may have multiple EL layers between a pair of electrodes. Fig. 1B shows a light-emitting device with a tandem structure having two EL layers (EL layer 103a and EL layer 103b) between a pair of electrodes and a charge generating layer 104 between the two EL layers. The light-emitting device with the tandem structure can be driven at a low voltage and can reduce power consumption.

[0110] The charge generation layer 104 has a function of injecting electrons into one of the EL layers 103a and 103b and injecting holes into the other when a voltage is applied between the first electrode 101 and the second electrode 102. Therefore, in Fig. 1B, when a voltage is applied to the first electrode 101 so that the first electrode 101 has a higher potential than the second electrode 102, electrons are injected from the charge generation layer 104 into the EL layer 103a and holes are injected into the EL layer 103b.

[0111] From the viewpoint of light extraction efficiency, the charge generation layer 104 preferably transmits near-infrared light (specifically, the transmittance of the charge generation layer 104 for near-infrared light is 40% or more). The charge generation layer 104 also functions even if it has a lower conductivity than the first electrode 101 and the second electrode 102.

[0112] FIG. 1C shows an example of a laminated structure of the EL layer 103. In this embodiment, the first electrode 101 functions as an anode, and the second electrode 102 functions as a cathode. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are laminated in this order on the first electrode 101. The hole injection layer 111, the hole transport layer 112, the light-emitting layer 113, the electron transport layer 114, and the electron injection layer 115 may each have a single-layer structure or a laminated structure. Even in the case of having a plurality of EL layers as in the tandem structure shown in FIG. 1B, the same laminated structure as the EL layer 103 shown in FIG. 1C can be applied to each EL layer. In addition, when the first electrode 101 is a cathode and the second electrode 102 is an anode, the laminated order is reversed.

[0113] The light-emitting layer 113 may have a light-emitting substance or a combination of a plurality of substances, and may have a structure capable of obtaining fluorescent or phosphorescent emission of a desired wavelength. The light-emitting layer 113 may have a stacked structure having different emission wavelengths. In this case, different materials may be used as the light-emitting substance and other substances for each stacked light-emitting layer. The EL layer 103a and the EL layer 103b shown in FIG. 1B may have a structure that emits light of different wavelengths. In this case, different materials may be used as the light-emitting substance and other substances for each light-emitting layer.

[0114] In the light-emitting device according to one embodiment of the present invention, the light emitted from the EL layer may be resonated between a pair of electrodes to enhance the light emission. For example, in FIG. 1C, the first electrode 101 is a reflective electrode and the second electrode 102 is a semi-transmissive / semi-reflective electrode (an electrode having transparency and reflectivity to near-infrared light), thereby forming a micro-optical resonator (microcavity) structure, and the light emitted from the EL layer 103 can be enhanced.

[0115] In addition, when the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a conductive film reflective to near-infrared light and a conductive film transmissive to near-infrared light, optical adjustment can be performed by controlling the film thickness of the transmissive conductive film. Specifically, it is preferable to adjust the inter-electrode distance between the first electrode 101 and the second electrode 102 to be approximately mλ / 2 (where m is a natural number) for the wavelength λ of light obtained from the light-emitting layer 113.

[0116] In order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained, and the optical distance from the second electrode 102 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained, to be approximately (2m'+1)λ / 4 (where m' is a natural number). Note that the light-emitting region here refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0117] By carrying out such optical adjustment, the spectrum of the light obtained from the light emitting layer 113 can be narrowed, and light of a desired wavelength can be obtained.

[0118] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can be strictly said to be the total thickness from the reflection area in the first electrode 101 to the reflection area in the second electrode 102. However, since it is difficult to strictly determine the reflection area in the first electrode 101 or the second electrode 102, it is assumed that the above-mentioned effect can be sufficiently obtained by assuming any position of the first electrode 101 or the second electrode 102 as the reflection area. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be strictly said to be the optical distance between the reflection area in the first electrode 101 and the light-emitting area in the light-emitting layer from which the desired light is obtained. However, since it is difficult to strictly determine the reflection area in the first electrode 101 or the light-emitting area in the light-emitting layer from which the desired light is obtained, it is assumed that the above-mentioned effect can be sufficiently obtained by assuming any position of the first electrode 101 as the reflection area and any position of the light-emitting layer from which the desired light is obtained as the light-emitting area.

[0119] At least one of the first electrode 101 and the second electrode 102 is an electrode having translucency to near-infrared light. The electrode having translucency to near-infrared light has a transmittance to near-infrared light of 40% or more. When the electrode having translucency to near-infrared light is the semi-transmissive / semi-reflective electrode, the electrode has a reflectance to near-infrared light of 20% or more, preferably 40% or more, and may be less than 100%, preferably 95% or less, and may be 80% or less or 70% or less. For example, the electrode has a reflectance to near-infrared light of 20% or more and 80% or less, preferably 40% or more and 70% or less. The resistivity of the electrode is 1×10 -2 Ωcm or less is preferable.

[0120] When the first electrode 101 or the second electrode 102 is an electrode (reflective electrode) having a reflectivity to near-infrared light, the reflectance of the reflective electrode to near-infrared light is set to 40% or more and 100% or less, preferably 70% or more and 100% or less. In addition, the resistivity of this electrode is 1×10 -2 Ωcm or less is preferable.

[0121] <Specific structure and manufacturing method of light-emitting device> Next, a specific structure and a manufacturing method of the light-emitting device will be described, using a light-emitting device having a single structure shown in FIG. 1C.

[0122] <First electrode and second electrode> As the material for forming the first electrode 101 and the second electrode 102, the following materials can be used in appropriate combination as long as the above-mentioned functions of both electrodes are satisfied. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used appropriately. Specific examples include In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, and In-W-Zn oxide. In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), and alloys containing these in appropriate combinations can also be used. In addition, elements belonging to Group 1 or 2 of the periodic table not exemplified above (e.g., lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), alloys containing appropriate combinations of these, graphene, etc. can be used.

[0123] When a light-emitting device having a microcavity structure is manufactured, the first electrode 101 is formed as a reflective electrode, and the second electrode 102 is formed as a semi-transmissive and semi-reflective electrode. Therefore, a single or multiple desired conductive materials can be used to form a single layer or a laminated layer. The second electrode 102 is formed by selecting a material in the same manner as above after the EL layer 103 is formed. These electrodes can be manufactured by sputtering or vacuum deposition.

[0124] In the light-emitting device shown in FIG. 1C, when the first electrode 101 is an anode, a hole injection layer 111 and a hole transport layer 112 are sequentially formed on the first electrode 101 by vacuum deposition.

[0125] <Hole injection layer and hole transport layer> The hole injection layer 111 is a layer that injects holes from the first electrode 101, which is an anode, to the EL layer 103, and is a layer that contains a material with high hole injection properties.

[0126] Materials with high hole injection properties include transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide, and phthalocyanine (abbreviation: H 2 Examples of the compounds that can be used include copper(II) phthalocyanine (abbreviation: CuPc) and phthalocyanine compounds such as copper(II) phthalocyanine (abbreviation: CuPc).

[0127] Materials with high hole injection properties include 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N- Aromatic amine compounds such as (4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0128] Examples of materials with high hole injection properties include poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl) methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. Alternatively, polymer compounds to which acids have been added, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviation: PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS), etc., can also be used.

[0129] A composite material containing a hole transport material and an acceptor material (electron accepting material) can also be used as a material with high hole injection properties. In this case, electrons are extracted from the hole transport material by the acceptor material, generating holes in the hole injection layer 111, and the holes are injected into the light emitting layer 113 via the hole transport layer 112. Note that the hole injection layer 111 may be formed as a single layer made of a composite material containing a hole transport material and an acceptor material, or may be formed by laminating the hole transport material and the acceptor material in separate layers.

[0130] The hole transport layer 112 is a layer that transports holes injected from the first electrode 101 by the hole injection layer 111 to the light emitting layer 113. The hole transport layer 112 is a layer containing a hole transport material. It is particularly preferable to use a hole transport material used for the hole transport layer 112 that has a highest occupied molecular orbital (HOMO) level that is the same as or close to the HOMO level of the hole injection layer 111.

[0131] As an acceptor material used for the hole injection layer 111, an oxide of a metal belonging to Groups 4 to 8 of the periodic table can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among them, molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is easy to handle. Other organic acceptors that can be used include quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives. Examples of acceptors having an electron-withdrawing group (a halogen group or a cyano group) include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), etc. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and preferable. In addition, radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group)[3] are preferred because they have very high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile].

[0132] The hole transport material used in the hole injection layer 111 and the hole transport layer 112 is 10 -6 cm 2 A substance having a hole mobility of / Vs or more is preferable. Note that other substances can also be used as long as they have a higher hole transporting property than an electron transporting property.

[0133] As the hole transporting material, a material having high hole transporting properties, such as a π-electron-rich heteroaromatic compound (eg, a carbazole derivative, a thiophene derivative, a furan derivative, etc.) or an aromatic amine (a compound having an aromatic amine skeleton), is preferable.

[0134] Examples of carbazole derivatives (compounds having a carbazole skeleton) include bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives) and aromatic amines having a carbazolyl group.

[0135] Specific examples of bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives) include 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(1,1'-biphenyl-4-yl)-3,3'-bi-9H-carbazole, 9,9'-bis(1,1'-biphenyl-3-yl)-3,3'-bi-9H-carbazole, 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), and 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP).

[0136] Specific examples of aromatic amines having a carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-yl, and N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-yl]. PCBBiF, 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBBi1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 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), PCzPCA1, PCzPCA2, PCzPCN1, 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,Examples of such compounds include 6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), and 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA).

[0137] In addition to the above, examples of the carbazole derivative include 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 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), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA).

[0138] Specific examples of thiophene derivatives (compounds having a thiophene skeleton) and furan derivatives (compounds having a furan skeleton) include compounds having a thiophene skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 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).

[0139] Specific examples of aromatic amines include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: :BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl) N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)- N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), TDATA, m-MTDATA, N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), DPAB, DNTPD, DPA3B, and the like.

[0140] As the hole transporting material, polymer compounds such as PVK, PVTPA, PTPDMA, and Poly-TPD can also be used.

[0141] The hole transporting material is not limited to the above, and various known materials can be used for the hole injection layer 111 and the hole transport layer 112 either alone or in combination.

[0142] In the light-emitting device shown in FIG. 1C, a light-emitting layer 113 is formed on a hole-transporting layer 112 by vacuum deposition.

[0143] <Light-emitting layer> The light-emitting layer 113 is a layer containing a light-emitting substance.

[0144] A light-emitting device according to one embodiment of the present invention includes a light-emitting organic compound as a light-emitting substance. The light-emitting organic compound emits near-infrared light. Specifically, the maximum peak wavelength of light emitted by the light-emitting organic compound is greater than 780 nm and less than or equal to 900 nm.

[0145] As the light-emitting organic compound, for example, it is possible to use the organometallic complex described in Embodiment 1. In addition, as the light-emitting organic compound, it is also possible to use the organometallic complex described in the examples described later.

[0146] Light-emitting layer 113 can have one or more light-emitting materials.

[0147] The light-emitting layer 113 may contain one or more organic compounds (host materials, assist materials, etc.) in addition to a light-emitting substance (guest material). As the one or more organic compounds, one or both of a hole-transporting material and an electron-transporting material described in this embodiment can be used. As the one or more organic compounds, a bipolar material may be used.

[0148] There is no particular limitation on the light-emitting substance that can be used for the light-emitting layer 113, and a light-emitting substance that converts singlet excitation energy into light emission in the near-infrared light region, or a light-emitting substance that converts triplet excitation energy into light emission in the near-infrared light region can be used.

[0149] Examples of luminescent substances that convert singlet excitation energy into luminescence include substances that emit fluorescence (fluorescent materials), such as pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives.

[0150] Examples of light-emitting substances that convert triplet excitation energy into light include substances that emit phosphorescence (phosphorescent materials) and thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

[0151] Examples of phosphorescent materials include organometallic complexes (particularly iridium complexes) having a 4H-triazole skeleton, 1H-triazole skeleton, imidazole skeleton, pyrimidine skeleton, pyrazine skeleton, or pyridine skeleton, organometallic complexes (particularly iridium complexes) having a phenylpyridine derivative having an electron-withdrawing group as a ligand, platinum complexes, and rare earth metal complexes.

[0152] The light-emitting device of one embodiment of the present invention may have a light-emitting substance other than the light-emitting substance that emits near-infrared light. For example, the light-emitting device of one embodiment of the present invention may have a light-emitting substance that emits visible light (red, blue, green, etc.) in addition to the light-emitting substance that emits near-infrared light.

[0153] As the organic compound (host material, assist material, etc.) used in the light-emitting layer 113, one or more substances having a larger energy gap than the energy gap of the light-emitting substance can be selected and used.

[0154] When the light-emitting substance used in the light-emitting layer 113 is a fluorescent material, an organic compound that has a high energy level in a singlet excited state and a low energy level in a triplet excited state is preferably used as the organic compound used in combination with the light-emitting substance.

[0155] Although some of the examples overlap with the above specific examples, specific examples of organic compounds are shown below from the viewpoint of preferable combinations with light-emitting substances (fluorescent materials, phosphorescent materials).

[0156] When the luminescent substance is a fluorescent material, examples of organic compounds that can be used in combination with the luminescent substance include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0157] Specific examples of organic compounds (host materials) used in combination with fluorescent materials include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), PCPN, 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA ), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N-(9,10-di phenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), CzPA, 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl 1,2-diphenyl-4'-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene, etc.

[0158] When the light-emitting substance is a phosphorescent material, an organic compound having a triplet excitation energy (energy difference between the ground state and the triplet excited state) larger than the triplet excitation energy of the light-emitting substance may be selected as the organic compound to be used in combination with the light-emitting substance.

[0159] When multiple organic compounds (e.g., a first host material and a second host material (or assist material)) are used in combination with a light-emitting substance to form an exciplex, it is preferable to use these multiple organic compounds in combination with a phosphorescent material (particularly an organometallic complex).

[0160] With this structure, light emission using ExTET (Exciplex-Triplet Energy Transfer), which is an energy transfer from an exciplex to a light-emitting substance, can be efficiently obtained. Note that a combination of a plurality of organic compounds is preferably one that easily forms an exciplex, and it is particularly preferable to combine a compound that easily receives holes (hole transporting material) with a compound that easily receives electrons (electron transporting material). Note that the materials shown in this embodiment can be used as specific examples of the hole transporting material and the electron transporting material. With this structure, high efficiency, low voltage, and long life of the light-emitting device can be simultaneously achieved.

[0161] When the luminescent substance is a phosphorescent material, examples of organic compounds that can be used in combination with the luminescent substance include aromatic amines, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, zinc- or aluminum-based metal complexes, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, and phenanthroline derivatives.

[0162] Among the above, specific examples of the aromatic amines (compounds having an aromatic amine skeleton), carbazole derivatives, dibenzothiophene derivatives (thiophene derivatives), and dibenzofuran derivatives (furan derivatives), which are organic compounds with high hole-transport properties, are the same as the specific examples of the hole-transport materials shown above.

[0163] Specific examples of zinc and aluminum metal complexes, which are organic compounds with high electron transport properties, include tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq), etc. 3 ), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2 ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), and other metal complexes having a quinoline skeleton or a benzoquinoline skeleton.

[0164] In addition, metal complexes having oxazole or thiazole ligands, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), can also be used.

[0165] Specific examples of organic compounds with high electron transport properties, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, and phenanthroline derivatives, include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1 ,3,4-Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-( dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBT PDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II).

[0166] Specific examples of heterocyclic compounds having a diazine skeleton, a heterocyclic compound having a triazine skeleton, and a heterocyclic compound having a pyridine skeleton, which are organic compounds with high electron transport properties, include 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H -carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and the like.

[0167] As organic compounds with high electron transport properties, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used.

[0168] A TADF material is a material that can upconvert a triplet excited state to a singlet excited state with a small amount of thermal energy (reverse intersystem crossing), and efficiently emits light (fluorescence) from the singlet excited state. Conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited level and the singlet excited level of 0 eV or more and 0.2 eV or less, and preferably 0 eV or more and 0.1 eV or less. Delayed fluorescence in TADF materials refers to light emission that has a spectrum similar to that of normal fluorescence, but has a significantly long lifetime. The lifetime is approximately 10 -6 seconds or more, preferably 10 -3 More than seconds.

[0169] Examples of TADF materials include fullerene and its derivatives, acridine derivatives such as proflavine, and eosin. Examples of metal-containing porphyrins include those containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (abbreviated as SnF 2 (Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF 2 (Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF 2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF 2 (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF 2 (OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF 2 (Etio I)), octaethylporphyrin-platinum chloride complex (abbreviation: PtCl 2 OEP) etc.

[0170] Other examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), PCCzPTzn, 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation Heterocyclic compounds having a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 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 be used. Note that a substance in which a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded is particularly preferred because the donor property of the π-electron rich heteroaromatic ring and the acceptor property of the π-electron deficient heteroaromatic ring are both strong, and the energy difference between the singlet excited state and the triplet excited state is small.

[0171] In addition, when a TADF material is used, it can be used in combination with other organic compounds, particularly with the host material, hole transport material, and electron transport material described above.

[0172] Moreover, the above-mentioned materials can be used in combination with low molecular weight materials or high molecular weight materials to form the light emitting layer 113. Moreover, for film formation, a known method (such as a vapor deposition method, a coating method, or a printing method) can be appropriately used.

[0173] In the light-emitting device shown in FIG. 1C, an electron-transporting layer 114 is formed on light-emitting layer 113 .

[0174] <Electron transport layer> The electron transport layer 114 is a layer that transports electrons injected from the second electrode 102 by the electron injection layer 115 to the light-emitting layer 113. The electron transport layer 114 is a layer that contains an electron transport material. The electron transport material used for the electron transport layer 114 has a concentration of 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferable. Note that other substances can also be used as long as they have a higher electron transporting property than a hole transporting property.

[0175] Examples of the electron-transporting material that can be used include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, and metal complexes having a thiazole skeleton, as well as materials with high electron-transporting properties, such as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron-deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds.

[0176] As specific examples of the electron transporting material, the materials listed above can be used.

[0177] Next, in the light-emitting device shown in FIG. 1C, an electron injection layer 115 is formed on the electron transport layer 114 by vacuum deposition.

[0178] <Electron injection layer> The electron injection layer 115 is a layer containing a substance with high electron injection properties. The electron injection layer 115 may contain lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF 2 ), lithium oxide (LiO x Alkali metals, alkaline earth metals, or compounds thereof, such as erbium fluoride (ErF 3) can be used. Furthermore, an electride may be used for the electron injection layer 115. For example, an electride may be a substance in which a high concentration of electrons is added to a mixed oxide of calcium and aluminum. The above-mentioned substance constituting the electron transport layer 114 can also be used.

[0179] In addition, a composite material containing an electron transporting material and a donor material (electron donor material) may be used for the electron injection layer 115. Such a composite material has excellent electron injection and transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons, and specifically, for example, the above-mentioned electron transporting material (metal complex, heteroaromatic compound, etc.) used for the electron transport layer 114 can be used. As the electron donor, any substance that exhibits electron donating properties to the organic compound may be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferable, and examples thereof include lithium, cesium, magnesium, calcium, erbium, and ytterbium. In addition, alkali metal oxides and alkaline earth metal oxides are preferable, and examples thereof include lithium oxide, calcium oxide, and barium oxide. In addition, a Lewis base such as magnesium oxide can also be used. In addition, an organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used.

[0180] <Charge generation layer> In the light-emitting device shown in FIG. 1B, the charge generation layer 104 has the function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the first electrode 101 (anode) and the second electrode 102 (cathode).

[0181] The charge generating layer 104 may be configured to contain a hole transport material and an acceptor material (electron accepting material), or may be configured to contain an electron transport material and a donor material. By forming the charge generating layer 104 with such a configuration, it is possible to suppress an increase in driving voltage when an EL layer is laminated.

[0182] The hole transporting material, the acceptor material, the electron transporting material, and the donor material may each be the materials described above.

[0183] In addition, a vacuum process such as a deposition method, or a solution process such as a spin coating method or an inkjet method can be used to manufacture the light-emitting device shown in this embodiment. When a deposition method is used, a physical deposition method (PVD method) such as a sputtering method, an ion plating method, an ion beam deposition method, a molecular beam deposition method, or a vacuum deposition method, or a chemical deposition method (CVD method) can be used. In particular, the functional layers (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer) and the charge generation layer included in the EL layer can be formed by a deposition method (vacuum deposition method, etc.), a coating method (dip coating method, die coating method, bar coating method, spin coating method, spray coating method, etc.), a printing method (inkjet method, screen (screen printing) method, offset (lithographic printing) method, flexo (relief printing) method, gravure method, microcontact method, etc.), or the like.

[0184] The materials of the functional layer and the charge generating layer constituting the EL layer 103 are not limited to the above-mentioned materials. For example, the material of the functional layer may be a polymer compound (oligomer, dendrimer, polymer, etc.), a medium molecular compound (a compound in the intermediate range between a low molecular weight and a high molecular weight: molecular weight 400 to 4000), an inorganic compound (quantum dot material, etc.), etc. may be used. Note that the quantum dot material may be a colloidal quantum dot material, an alloy type quantum dot material, a core-shell type quantum dot material, a core type quantum dot material, etc.

[0185] [Light emitting device configuration example 1] Fig. 2A shows a top view of the light emitting device, and Fig. 2B and Fig. 2C show cross-sectional views between dashed lines X1-Y1 and X2-Y2 in Fig. 2A. The light emitting device shown in Fig. 2A to Fig. 2C can be used, for example, in a lighting device. The light emitting device may be any of bottom emission, top emission, and dual emission.

[0186] 2B includes a substrate 490a, a substrate 490b, a conductive layer 406, a conductive layer 416, an insulating layer 405, an organic EL device 450 (a first electrode 401, an EL layer 402, and a second electrode 403), and an adhesive layer 407. The organic EL device 450 can also be called a light-emitting element, an organic EL element, a light-emitting device, or the like. The EL layer 402 preferably includes the organometallic complex described in Embodiment 1 as a light-emitting organic compound in the light-emitting layer.

[0187] Organic EL device 450 has a first electrode 401 on a substrate 490a, an EL layer 402 on the first electrode 401, and a second electrode 403 on the EL layer 402. Organic EL device 450 is encapsulated by substrate 490a, adhesive layer 407, and substrate 490b.

[0188] The ends of the first electrode 401, the conductive layer 406, and the conductive layer 416 are covered with an insulating layer 405. The conductive layer 406 is electrically connected to the first electrode 401, and the conductive layer 416 is electrically connected to the second electrode 403. The conductive layer 406 covered with the insulating layer 405 via the first electrode 401 functions as an auxiliary wiring and is electrically connected to the first electrode 401. Having an auxiliary wiring electrically connected to the electrode of the organic EL device 450 is preferable because it can suppress a voltage drop caused by the resistance of the electrode. The conductive layer 406 may be provided on the first electrode 401. Also, an auxiliary wiring electrically connected to the second electrode 403 may be provided on the insulating layer 405 or the like.

[0189] The substrate 490a and the substrate 490b can each be made of glass, quartz, ceramic, sapphire, organic resin, etc. When the substrate 490a and the substrate 490b are made of a flexible material, the flexibility of the display device can be increased.

[0190] The light-emitting surface of the light-emitting device may be provided with a light extraction structure to increase the light extraction efficiency, an antistatic film to suppress the adhesion of dust, a water-repellent film to prevent the adhesion of dirt, a hard coat film to suppress the occurrence of scratches during use, an impact absorbing layer, etc.

[0191] Examples of insulating materials that can be used for the insulating layer 405 include resins such as acrylic resin and epoxy resin, and inorganic insulating materials such as silicon oxide, silicon oxynitride, silicon nitride oxide, silicon nitride, and aluminum oxide.

[0192] For the adhesive layer 407, various curing adhesives such as a photo-curing adhesive such as an ultraviolet curing adhesive, a reaction curing adhesive, a heat curing adhesive, and an anaerobic adhesive can be used. Examples of such adhesives include epoxy resin, acrylic resin, silicone resin, phenolic resin, polyimide resin, imide resin, PVC (polyvinyl chloride) resin, PVB (polyvinyl butyral) resin, and EVA (ethylene vinyl acetate) resin. In particular, a material with low moisture permeability such as epoxy resin is preferable. A two-liquid mixed resin may also be used. An adhesive sheet or the like may also be used.

[0193] The light emitting device shown in FIG. 2C includes barrier layer 490c, conductive layer 406, conductive layer 416, insulating layer 405, organic EL device 450, adhesive layer 407, barrier layer 423, and substrate 490b.

[0194] Barrier layer 490c shown in FIG. 2C includes substrate 420, adhesion layer 422, and high barrier insulating layer 424.

[0195] 2C, organic EL device 450 is disposed between insulating layer 424 with high barrier properties and barrier layer 423. Therefore, even if a resin film with relatively low waterproof properties is used for substrate 420 and substrate 490b, it is possible to prevent impurities such as water from entering the organic EL device and shortening its lifespan.

[0196] For the substrate 420 and the substrate 490b, for example, polyester resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), polyacrylonitrile resin, acrylic resin, polyimide resin, polymethyl methacrylate resin, polycarbonate (PC) resin, polyethersulfone (PES) resin, polyamide resin (nylon, aramid, etc.), polysiloxane resin, cycloolefin resin, polystyrene resin, polyamideimide resin, polyurethane resin, polyvinyl chloride resin, polyvinylidene chloride resin, polypropylene resin, polytetrafluoroethylene (PTFE) resin, ABS resin, cellulose nanofiber, etc. For the substrate 420 and the substrate 490b, glass having a thickness sufficient to provide flexibility may be used.

[0197] The insulating layer 424 having high barrier properties is preferably an inorganic insulating film. Examples of the inorganic insulating film that can be used include a silicon nitride film, a silicon oxynitride film, a silicon oxide film, a silicon nitride oxide film, an aluminum oxide film, and an aluminum nitride film. A hafnium oxide film, an yttrium oxide film, a zirconium oxide film, a gallium oxide film, a tantalum oxide film, a magnesium oxide film, a lanthanum oxide film, a cerium oxide film, and a neodymium oxide film may also be used. Two or more of the above insulating films may be stacked.

[0198] The barrier layer 423 preferably has at least one inorganic film. For example, the barrier layer 423 may have a single layer structure of an inorganic film or a laminated structure of an inorganic film and an organic film. The inorganic insulating film is suitable as the inorganic film. For example, the laminated structure may be a silicon oxynitride film, a silicon oxide film, an organic film, a silicon oxide film, and a silicon nitride film formed in this order. By forming the protective layer into a laminated structure of an inorganic film and an organic film, impurities (typically, hydrogen, water, etc.) that may enter the organic EL device 450 can be suitably suppressed.

[0199] The insulating layer 424 and the organic EL device 450 having high barrier properties can be formed directly on the substrate 420 having flexibility. In this case, the adhesive layer 422 is not necessary. The insulating layer 424 and the organic EL device 450 can be formed on a hard substrate via a peeling layer and then transferred to the substrate 420. For example, the insulating layer 424 and the organic EL device 450 may be peeled off from the hard substrate by applying heat, force, laser light, or the like to the peeling layer, and then transferred to the substrate 420 by bonding the substrate 420 using the adhesive layer 422. As the peeling layer, for example, a laminated structure of inorganic films including a tungsten film and a silicon oxide film, an organic resin film such as polyimide, or the like can be used. When a hard substrate is used, the insulating layer 424 can be formed at a high temperature compared to a resin substrate, and therefore the insulating layer 424 can be made into a dense insulating film having extremely high barrier properties.

[0200] [Light-emitting device configuration example 2] The light-emitting device of one embodiment of the present invention can be a passive matrix type or an active matrix type. An active matrix type light-emitting device will be described with reference to FIG.

[0201] Fig. 3A shows a top view of the light emitting device, and Fig. 3B is a cross-sectional view taken along dashed line AA' shown in Fig. 3A.

[0202] The active matrix light emitting device shown in FIG. 3A and FIG. 3B includes a pixel portion 302, a circuit portion 303, a circuit portion 304a, and a circuit portion 304b.

[0203] Each of the circuit portion 303, the circuit portion 304a, and the circuit portion 304b can function as a scanning line driver circuit (gate driver) or a signal line driver circuit (source driver), or may be a circuit that electrically connects an external gate driver or source driver to the pixel portion 302.

[0204] A lead wiring 307 is provided on the first substrate 301. The lead wiring 307 is electrically connected to an FPC 308, which is an external input terminal. The FPC 308 transmits signals (e.g., video signals, clock signals, start signals, reset signals, etc.) and potentials from the outside to the circuit portion 303, the circuit portion 304a, and the circuit portion 304b. A printed wiring board (PWB) may be attached to the FPC 308. The configuration shown in FIGS. 3A and 3B can also be called a light-emitting module having a light-emitting device (or a light-emitting apparatus) and an FPC.

[0205] The pixel portion 302 has a plurality of pixels each having an organic EL device 317, a transistor 311, and a transistor 312. The transistor 312 is electrically connected to a first electrode 313 of the organic EL device 317. The transistor 311 functions as a switching transistor. The transistor 312 functions as a current control transistor. Note that the number of transistors included in each pixel is not particularly limited and can be appropriately provided as necessary.

[0206] The circuit portion 303 has a plurality of transistors including a transistor 309 and a transistor 310. The circuit portion 303 may be formed of a circuit including transistors of the same polarity (either N-type or P-type), or may be formed of a CMOS circuit including an N-type transistor and a P-type transistor. The circuit portion 303 may also be configured to have an external driver circuit.

[0207] The structure of the transistor included in the light-emitting device of this embodiment is not particularly limited. For example, a planar transistor, a staggered transistor, an inverted staggered transistor, or the like can be used. In addition, either a top-gate type or a bottom-gate type transistor structure may be used. Alternatively, gates may be provided above and below a semiconductor layer in which a channel is formed.

[0208] The crystallinity of a semiconductor material used in 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 partially having a crystalline region) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0209] The semiconductor layer of the transistor preferably contains a metal oxide (also referred to as an oxide semiconductor). Alternatively, the semiconductor layer of the transistor may contain silicon. Examples of silicon include amorphous silicon and crystalline silicon (such as low-temperature polysilicon and single crystal silicon).

[0210] The semiconductor layer preferably contains, for example, indium, M (M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, M is preferably one or more selected from aluminum, gallium, yttrium, and tin.

[0211] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also referred to as IGZO) as the semiconductor layer.

[0212] When the semiconductor layer is an In-M-Zn oxide, the sputtering target used to deposit the In-M-Zn oxide preferably has an atomic ratio of In equal to or greater than the atomic ratio of M. Examples of atomic ratios of metal elements in such sputtering targets include In:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:3, In:M:Zn=3:1:2, In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7, In:M:Zn=5:1:8, In:M:Zn=6:1:6, In:M:Zn=5:2:5, and the like.

[0213] The transistors included in the circuit portion 303, the circuit portion 304a, and the circuit portion 304b may have the same structure or may have different structures from the transistors included in the pixel portion 302. The transistors included in the circuit portion 303, the circuit portion 304a, and the circuit portion 304b may all have the same structure or may have two or more types. Similarly, the transistors included in the pixel portion 302 may all have the same structure or may have two or more types.

[0214] An end of the first electrode 313 is covered with an insulating layer 314. For the insulating layer 314, an organic compound such as a negative photosensitive resin or a positive photosensitive resin (acrylic resin) or an inorganic compound such as silicon oxide, silicon oxynitride, or silicon nitride can be used. The upper end or lower end of the insulating layer 314 preferably has a curved surface having a curvature. This can improve the coverage of the film formed on the insulating layer 314.

[0215] An EL layer 315 is provided over the first electrode 313, and a second electrode 316 is provided over the EL layer 315. The EL layer 315 includes a light-emitting layer, a hole-injection layer, a hole-transport layer, an electron-transport layer, an electron-injection layer, a charge-generation layer, and the like. The EL layer 315 preferably includes, in its light-emitting layer, the organometallic complex described in Embodiment 1 as a light-emitting organic compound.

[0216] The plurality of transistors and the plurality of organic EL devices 317 are sealed by the first substrate 301, the second substrate 306, and the sealant 305. A space 318 surrounded by the first substrate 301, the second substrate 306, and the sealant 305 may be filled with an inert gas (nitrogen, argon, etc.) or an organic substance (including the sealant 305).

[0217] An epoxy resin or glass frit can be used for the sealant 305. Note that it is preferable to use a material that is as impermeable to moisture and oxygen as possible for the sealant 305. When glass frit is used as the sealant, it is preferable that the first substrate 301 and the second substrate 306 are glass substrates in terms of adhesiveness.

[0218] This embodiment mode can be combined with other embodiment modes as appropriate.

[0219] (Embodiment 3) In this embodiment, electronic devices in which the light-emitting device of one embodiment of the present invention can be used will be described with reference to FIGS.

[0220] FIG. 4A shows a biometric authentication device for finger veins, and includes a housing 911, a light source 912, a detection stage 913, and the like. By placing a finger on the detection stage 913, the shape of the veins can be imaged. A light source 912 that emits near-infrared light is provided on the upper part of the detection stage 913, and an imaging device 914 is provided on the lower part. The detection stage 913 is made of a material that transmits near-infrared light, and the near-infrared light that is irradiated from the light source 912 and transmitted through the finger can be imaged by the imaging device 914. An optical system may be provided between the detection stage 913 and the imaging device 914. The above-mentioned device configuration can also be used in a biometric authentication device for palm veins.

[0221] The light-emitting device according to one embodiment of the present invention can be used for the light source 912. The light-emitting device according to one embodiment of the present invention can be installed in a curved shape and can irradiate light uniformly to an object. In particular, the light-emitting device is preferably a light-emitting device that emits near-infrared light having the strongest peak intensity in a wavelength range of 760 nm to 900 nm. The position of veins can be detected by receiving light that has passed through a finger, a palm, or the like and imaging it. This function can be used for biometric authentication. Furthermore, by combining the light-emitting device with a global shutter system, highly accurate sensing is possible even if the object moves.

[0222] Furthermore, the light source 912 can have a plurality of light emitting units, such as light emitting units 915, 916, and 917 shown in Fig. 4B. Each of the light emitting units 915, 916, and 917 may emit light at a different wavelength, and each can irradiate light at a different timing. Therefore, by changing the wavelength and angle of the irradiated light, different images can be captured continuously, and therefore multiple images can be used for authentication, thereby achieving high security.

[0223] FIG. 4C shows a biometric authentication device for palm veins, which includes a housing 921, an operation button 922, a detection unit 923, a light source 924 that emits near-infrared light, and the like. The shape of the veins in the palm can be recognized by holding the hand over the detection unit 923. A personal identification number or the like can also be input using the operation button. A light source 924 is disposed around the detection unit 923 and irradiates an object (hand). Then, reflected light from the object is incident on the detection unit 923. A light-emitting device according to one embodiment of the present invention can be used for the light source 924. An imaging device 925 is disposed directly below the detection unit 923 and can capture an image of the object (the entire image of the hand). Note that an optical system may be provided between the detection unit 923 and the imaging device 925. The above-described device configuration can also be used for a biometric authentication device for finger veins.

[0224] FIG. 4D shows a non-destructive inspection device, which includes a housing 931, an operation panel 932, a transport mechanism 933, a monitor 934, a detection unit 935, a light source 938 that emits near-infrared light, and the like. The light-emitting device according to one embodiment of the present invention can be used as the light source 938. A member to be inspected 936 is transported by the transport mechanism 933 to a position directly below the detection unit 935. The member to be inspected 936 is irradiated with near-infrared light from the light source 938, and the transmitted light is captured by an imaging device 937 provided in the detection unit 935. The captured image is displayed on the monitor 934. The member is then transported to the exit of the housing 931, where defective products are separated and collected. By capturing images using near-infrared light, defective elements such as defects and foreign bodies inside the member to be inspected can be detected non-destructively and at high speed.

[0225] FIG. 4E illustrates a mobile phone, which includes a housing 981, a display portion 982, operation buttons 983, an external connection port 984, a speaker 985, a microphone 986, a first camera 987, a second camera 988, and the like. The mobile phone includes a touch sensor in the display portion 982. The housing 981 and the display portion 982 are flexible. Any operation, such as making a call or inputting characters, can be performed by touching the display portion 982 with a finger, a stylus, or the like. The first camera 987 can acquire a visible light image, and the second camera 988 can acquire an infrared light image (near-infrared light image). The mobile phone or the display portion 982 illustrated in FIG. 4E may include a light-emitting device of one embodiment of the present invention.

[0226] This embodiment mode can be combined with other embodiment modes as appropriate. EXAMPLES

[0227] (Synthesis Example 1) Example 1 In this example, a method for synthesizing an organometallic complex according to one embodiment of the present invention will be described. In this example, bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-2-benzo[g]quinoxalinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ) represented by structural formula (100) in Embodiment 1 will be described. 2 O,O') Iridium(III) (abbreviation: [Ir(dmdpbq) 2 The synthesis method of (dpm)] is explained.

[0228] [ka]

[0229] <Step 1: Synthesis of 2,3-bis-(3,5-dimethylphenyl)-2-benzo[g]quinoxaline (abbreviation: Hdmdpbq)> First, in step 1, Hdmdpbq, an organic compound according to one embodiment of the present invention and represented by structural formula (200), was synthesized. 3.20 g of 3,3',5,5'-tetramethylbenzyl, 1.97 g of 2,3-diaminonaphthalene, and 60 mL of ethanol were placed in a three-neck flask equipped with a reflux condenser, and the inside of the flask was replaced with nitrogen, followed by stirring at 90°C for 7.5 hours. After a predetermined time had elapsed, the solvent was distilled off. The product was then purified by silica gel column chromatography using toluene as a developing solvent to obtain the target product (yellow solid, yield 3.73 g, 79%). The synthesis scheme of step 1 is shown in (a-1).

[0230] [ka]

[0231] Nuclear magnetic resonance spectroscopy of the yellow solid obtained in step 1 ( 1 The results of the analysis by H-NMR are shown below. 1 The H-NMR chart is shown in Figure 5. From this, it was found that Hdmdpbq represented by structural formula (200) was obtained in this example.

[0232] The obtained material 1 The 1 H NMR data is shown below. 1 H-NMR.δ(CD 2 Cl 2 ):2.28(s,12H),7.01(s,2H),7.16(s,4H),7.56-7.58(m,2H),8.11-8.13(m,2H),8.74(s,2H).

[0233] Step 2: Di-μ-chloro-tetrakis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-2-benzo[g]quinoxalinyl-κN]phenyl-κC}diiridium(III) (abbreviation: [Ir(dmdpbq) 2 Cl] 2 Synthesis of Next, in step 2, a dinuclear complex according to one embodiment of the present invention, represented by structural formula (210), [Ir(dmdpbq) 2 Cl]2 The compound was synthesized using 15 mL of 2-ethoxyethanol, 5 mL of water, 1.81 g of Hdmdpbq obtained in step 1, and iridium chloride hydrate (IrCl 3 H 2 0.66 g of 1,2-dichlorophenyl ether (Furuya Metals) was placed in a recovery flask equipped with a reflux condenser, and the atmosphere in the flask was replaced with argon. After that, the flask was irradiated with microwaves (2.45 GHz, 100 W) for 2 hours to cause a reaction. After the specified time had passed, the resulting residue was suction filtered and washed with methanol to obtain the target product (black solid, yield 1.76 g, 81%). The synthesis scheme of step 2 is shown in (a-2).

[0234] [ka]

[0235] <Step 3: [Ir(dmdpbq) 2 Synthesis of (dpm) In step 3, an organometallic complex according to one embodiment of the present invention, represented by structural formula (100), [Ir(dmdpbq) 2 (dpm)] was synthesized using 20 mL of 2-ethoxyethanol and the [Ir(dmdpbq) 2 Cl] 2 1.75g ​​of 1,000g of dipivaloylmethane (abbreviation: Hdpm), 0.50g of dipivaloylmethane (abbreviation: Hdpm), and 0.95g of sodium carbonate were placed in a recovery flask equipped with a reflux tube, and the atmosphere in the flask was replaced with argon. After that, microwaves (2.45GHz 100W) were irradiated for 3 hours. The obtained residue was suction filtered with methanol, and then washed with water and methanol. The obtained solid was purified by silica gel column chromatography using dichloromethane as a developing solvent, and then recrystallized with a mixed solvent of dichloromethane and methanol to obtain the target product (dark green solid, yield 0.42g, 21% yield). 0.41g of the obtained dark green solid was sublimated and purified by train sublimation. The sublimation purification conditions were a pressure of 2.7 Pa, and the dark green solid was heated at 300°C while flowing argon gas at a flow rate of 10.5mL / min. After sublimation purification, a dark green solid was obtained with a yield of 78%. The synthesis scheme of step 3 is shown in (a-3).

[0236] [ka]

[0237] Nuclear magnetic resonance spectroscopy of the dark green solid obtained in step 3 ( 1 The results of the analysis by H-NMR are shown below. 1 The H-NMR chart is shown in FIG. 6. From this, in this example, [Ir(dmdpbq) 2 (dpm)] was obtained.

[0238] The obtained material 1 The 1 H NMR data is shown below. 1 H-NMR.δ(CD 2 Cl 2 ):0.75(s,18H),0.97(s,6H),2.01(s,6H),2.52(s,12H),4.86(s,1H),6.39(s,2H),7.15(s,2H), 7.31(s,2H),7.44-7.51(m,4H),7.80(d,2H),7.86(s,4H),8.04(d,2H),8.42(s,2H),8.58(s,2H).

[0239] Next, [Ir(dmdpbq) 2 The ultraviolet-visible absorption spectrum (hereinafter simply referred to as the "absorption spectrum") and emission spectrum of a dichloromethane solution of [(dpm)] were measured.

[0240] The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550, manufactured by JASCO Corporation) by placing a dichloromethane solution (0.010 mmol / L) in a quartz cell and measuring at room temperature. The emission spectrum was measured using a fluorometer (FS920, manufactured by Hamamatsu Photonics Corporation) by placing a deoxygenated dichloromethane solution (0.010 mmol / L) in a quartz cell under a nitrogen atmosphere, sealing it, and measuring at room temperature.

[0241] The obtained absorption spectrum and emission spectrum measurement results are shown in Figure 7. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity and emission intensity. In Figure 7, the thin solid line represents the absorption spectrum, and the thick solid line represents the emission spectrum. The absorption spectrum shown in Figure 7 is the result of subtracting the absorption spectrum measured by putting only dichloromethane into a quartz cell from the absorption spectrum measured by putting a dichloromethane solution (0.010 mmol / L) into a quartz cell.

[0242] As shown in FIG. 7, an organometallic complex according to one embodiment of the present invention, [Ir(dmdpbq) 2 (dpm)] showed an emission peak at 807 nm, and near-infrared emission was observed from the dichloromethane solution.

[0243] In addition, the obtained [Ir(dmdpbq) 2 The weight loss rate of [Ir(dmdpbq) (dpm)] was measured using a high vacuum differential thermobalance (TG-DTA2410SA, manufactured by Bruker AXS Co., Ltd.). The temperature was increased at a vacuum of 10 Pa and a heating rate of 10° C. / min, as shown in FIG. 2 (dpm)] had a weight loss rate of 100% (corresponding to the weight loss rate of −100% in FIG. 8), indicating good sublimability.

[0244] Based on the above, in this example, the organometallic complex of one embodiment of the present invention, [Ir(dmdpbq) 2 (dpm)] was successfully synthesized. [Ir(dmdpbq) 2 (dpm)] was confirmed to be capable of emitting near-infrared light and to have good sublimation properties.

[0245] [Ir(dmdpbq) 2 (dpm)] is an example of the case where X in general formula (G1) is an unsubstituted benzene ring. It is believed that near-infrared emission was obtained because X is a benzene ring, which extends the π-conjugated system, deepens the LUMO level, and stabilizes the energy. In addition, [Ir(dmdpbq) 2(dpm)] is R in general formula (G1). 1 , R 3 , R 6 , and R 8 This is an example where R is a methyl group. 1 , R 3 , R 6 , and R 8 Since all of the X's are methyl groups, even if X is a condensed ring (benzene ring), the decrease in sublimability can be suppressed, and it is believed that an organometallic complex that has good sublimability and emits near-infrared light can be obtained. EXAMPLES

[0246] In this example, the results of manufacturing a light-emitting device according to one embodiment of the present invention will be described. Specifically, the light-emitting device was manufactured using bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-2-benzo[g]quinoxalinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κC) described in Example 1. 2 O,O') Iridium(III) (abbreviation: [Ir(dmdpbq) 2 The structure, manufacturing method, and characteristics of a light-emitting device 1 using the compound (II) (structural formula (100)) in the light-emitting layer will be described.

[0247] The light-emitting device 1 produced in this example is an example of a light-emitting device having a light-emitting organic compound in a light-emitting layer, and the maximum peak wavelength of light emitted by the light-emitting organic compound is 760 nm or more and 900 nm or less. The light-emitting device 1 is also an example of a light-emitting device using an organometallic complex having a metal-carbon bond in the light-emitting organic compound.

[0248] 9A shows the structure of the light emitting device 1 used in this example, and its specific configuration is shown in Table 1. The chemical formulas of the materials used in this example are shown below.

[0249] [Table 1]

[0250] [ka]

[0251] <<Creating light-emitting device 1>> The light-emitting device 1 shown in this embodiment has a structure in which a first electrode 801 is formed on a substrate 800, a hole injection layer 811, a hole transport layer 812, a light-emitting layer 813, an electron transport layer 814, and an electron injection layer 815 are sequentially stacked on the first electrode 801, and a second electrode 803 is stacked on the electron injection layer 815, as shown in FIG. 9A.

[0252] First, a first electrode 801 was formed on a substrate 800. The electrode area was 4 mm 2 The dimensions of the first electrode 801 were (2 mm×2 mm). A glass substrate was used as the substrate 800. The first electrode 801 was formed by depositing indium tin oxide containing silicon oxide (ITSO) to a thickness of 110 nm by a sputtering method. In this embodiment, the first electrode 801 functions as an anode.

[0253] As a pretreatment, the surface of the substrate was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and then the substrate was allowed to cool for about 30 minutes.

[0254] Next, a hole injection layer 811 was formed on the first electrode 801. The hole injection layer 811 was formed by evaporating the solution in a vacuum deposition apparatus for 10 -4 After reducing the pressure to 10 Pa, 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II) and molybdenum oxide were co-evaporated in a ratio of DBT3P-II:molybdenum oxide = 2:1 (weight ratio) to a film thickness of 60 nm.

[0255] Next, a hole transport layer 812 was formed on the hole injection layer 811. The hole transport layer 812 was formed by vapor deposition using 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) so as to have a film thickness of 20 nm.

[0256] Next, a light-emitting layer 813 was formed over the hole-transport layer 812. 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) was used as a host material, N-(1,1′-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) was used as an assist material, and [Ir(dmdpbq) 2 (dpm)] was used, with a weight ratio of 2mDBTBPDBq-II:PCBBiF:[Ir(dmdpbq) 2 (dpm)] = 0.7:0.3:0.1. The film thickness was 40 nm.

[0257] Next, an electron transport layer 814 was formed on the light emitting layer 813. The electron transport layer 814 was formed by sequentially depositing 2mDBTBPDBq-II to a thickness of 20 nm and 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen) to a thickness of 70 nm.

[0258] Next, the electron injection layer 815 was formed on the electron transport layer 814. The electron injection layer 815 was formed by vapor deposition using lithium fluoride (LiF) so as to have a film thickness of 1 nm.

[0259] Next, a second electrode 803 was formed on the electron injection layer 815. The second electrode 803 was formed by vapor deposition of aluminum so as to have a film thickness of 200 nm. In this example, the second electrode 803 functions as a cathode.

[0260] Through the above steps, a light-emitting device including an EL layer 802 sandwiched between a pair of electrodes was formed on a substrate 800. Note that the hole injection layer 811, the hole transport layer 812, the light-emitting layer 813, the electron transport layer 814, and the electron injection layer 815 described in the above steps are functional layers that constitute the EL layer in one embodiment of the present invention. In addition, in all of the deposition steps in the above-described manufacturing method, deposition by resistance heating was used.

[0261] The light-emitting device fabricated as described above is sealed with another substrate (not shown). When sealing is performed using another substrate (not shown), another substrate (not shown) coated with an adhesive that is hardened by ultraviolet light is fixed on the substrate 800 in a glove box with a nitrogen atmosphere, and the substrates are bonded together so that the adhesive adheres to the periphery of the light-emitting device formed on the substrate 800. During sealing, 365 nm ultraviolet light is applied at 6 J / cm. 2 The adhesive was solidified by irradiation and then stabilized by heat treatment at 80°C for 1 hour.

[0262] <Operation characteristics of light-emitting device 1> The operating characteristics of the light-emitting device 1 were measured. The measurements were carried out at room temperature (an atmosphere maintained at 25° C.).

[0263] FIG. 10 shows the current density-radiant emittance characteristics of the light-emitting device 1. FIG. 11 shows the voltage-current density characteristics of the light-emitting device 1. FIG. 12 shows the current density-radiant flux characteristics of the light-emitting device 1. FIG. 13 shows the voltage-radiant emittance characteristics of the light-emitting device 1. FIG. 14 shows the current density-external quantum efficiency characteristics of the light-emitting device 1. The radiant emittance, radiant flux, and external quantum efficiency were calculated using radiance, assuming that the light distribution characteristics of the light-emitting device are Lambertian type.

[0264] Table 2 shows 7.4 W / sr / m 2 4 shows main initial characteristic values ​​of the light emitting device 1 in the vicinity.

[0265] [Table 2]

[0266] As shown in FIGS. 10 to 14 and Table 2, it was found that the light emitting device 1 exhibited excellent characteristics.

[0267] In addition, 51 mA / cm2 was applied to the light-emitting device 1. 2 FIG. 15 shows the emission spectrum when a current was passed at a current density of 1000 nm. The emission spectrum was measured using a near-infrared spectroradiometer (SR-NIR, manufactured by Topcon Corporation). As shown in FIG. 15, the light-emitting device 1 has an emission spectrum of 1000 nm when a current was passed at a current density of 1000 nm. 2 The emission spectrum showed a maximum peak at around 796 nm, which was due to the emission of [(dpm)].

[0268] The half-width of the emission spectrum was 67 nm. When converted to energy, this half-width is approximately 0.13 eV, which is quite narrow for emission from an organometallic complex. Light-emitting device 1 efficiently emits light in the range of 760 nm to 900 nm (or 780 nm to 880 nm), making it highly effective as a light source for sensor applications, etc.

[0269] <Reliability test of light-emitting device 1> Next, a reliability test was conducted on the light-emitting device 1. The results of the reliability test are shown in Fig. 16. In Fig. 16, the vertical axis indicates normalized luminous intensity (%) when the initial luminous intensity is taken as 100%, and the horizontal axis indicates driving time (h). The reliability test was conducted at a current density of 75 mA / cm 2 and the light-emitting device 1 was driven.

[0270] The results of the reliability test showed that the light-emitting device 1 had high reliability. This is because the light-emitting device 1 was made of an organometallic complex, [Ir(dmdpbq) 2 This can be said to be an effect of using the compound (structural formula (100)) in the light-emitting layer of the light-emitting device 1. EXAMPLES

[0271] In this example, the results of fabricating a light-emitting device according to one embodiment of the present invention are described. The light-emitting device 2 fabricated in this example is an example of a light-emitting device that has a light-emitting organic compound in a light-emitting layer and emits light with a maximum peak wavelength of 760 nm to 900 nm. The results of fabricating the light-emitting device 2 and measuring its characteristics are described below.

[0272] In the light-emitting device 2, the light-emitting organic compound is bis(dibenzo[a,i]naphtho[2,1-c]phenazin-10-yl-κC 10 ,κN 11 )(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O') Iridium(III) (abbreviation: [Ir(dbnphz) 2 In other words, the light-emitting device 2 is an example of a light-emitting device that uses an organometallic complex having a metal-carbon bond as a light-emitting organic compound. 2 A synthesis example of (dpm)) will be described later in the Reference Examples.

[0273] The specific configuration of the light-emitting device 2 used in this example is shown in Table 3. The structure of the light-emitting device 2 is similar to that of the light-emitting device 1 (FIG. 9A), and the fabrication method can be referred to Example 2. The chemical formulas of the materials used in this example are shown below.

[0274] [Table 3]

[0275] [ka]

[0276] <Operation characteristics of light-emitting device 2> The operating characteristics of the light-emitting device 2 were measured. The measurements were carried out at room temperature (an atmosphere maintained at 25° C.).

[0277] FIG. 17 shows the current density-radiant emittance characteristics of the light-emitting device 2. FIG. 18 shows the voltage-current density characteristics of the light-emitting device 2. FIG. 19 shows the current density-radiant flux characteristics of the light-emitting device 2. FIG. 20 shows the voltage-radiant emittance characteristics of the light-emitting device 2. FIG. 21 shows the current density-external quantum efficiency characteristics of the light-emitting device 2. The radiant emittance, radiant flux, and external quantum efficiency were calculated using radiance, assuming that the light distribution characteristics of the light-emitting device are Lambertian type.

[0278] Table 4 shows 0.11 W / sr / m 2 4 shows main initial characteristic values ​​of the light emitting device 2 in the vicinity.

[0279] [Table 4]

[0280] As shown in FIGS. 17 to 21 and Table 4, it was found that the light emitting device 2 exhibited excellent element characteristics.

[0281] In addition, 15 mA / cm2 is applied to the light-emitting device 2. 2 FIG. 22 shows the emission spectrum when a current was passed at a current density of 1000 nm. In FIG. 22, a near-infrared spectroradiometer (SR-NIR, manufactured by Topcon Corporation) was used to measure the emission spectrum. The light-emitting device 2 has an emission layer 813 containing [Ir(dbnphz) 2 The emission spectrum has a maximum peak at around 870 nm, which is due to the emission of [(dpm)].

[0282] The half-width of the emission spectrum was 63 nm. This half-width is converted to energy equivalent to approximately 0.10 eV, which is quite narrow for emission from an organometallic complex. Light-emitting device 2 efficiently emits light in the range of 760 nm to 900 nm (or 780 nm to 880 nm), making it highly effective as a light source for sensor applications, etc.

[0283] <Reliability test of light-emitting device 2> Next, a reliability test was carried out on the light-emitting device 2. The results of the reliability test are shown in Fig. 23. In Fig. 23, the vertical axis indicates normalized luminous intensity (%) when the initial luminous intensity is taken as 100%, and the horizontal axis indicates the operation time (h) of the element. The reliability test was carried out at a current density of 75 mA / cm 2 and the light-emitting device 2 was driven.

[0284] The results of the reliability test showed that the light emitting device 2 exhibited high reliability. EXAMPLES

[0285] In this example, the results of manufacturing a light-emitting device according to one embodiment of the present invention will be described. Specifically, the [Ir(dmdpbq) 2 The structure, manufacturing method, and characteristics of a light-emitting device 3 using the above-mentioned ZnO (dpm) in the light-emitting layer will be described.

[0286] The light-emitting device 3 produced in this example is an example of a light-emitting device having a light-emitting organic compound in a light-emitting layer, and the maximum peak wavelength of light emitted by the light-emitting organic compound is 760 nm or more and 900 nm or less. The light-emitting device 3 is also an example of a light-emitting device using an organometallic complex having a metal-carbon bond in the light-emitting organic compound.

[0287] The structure of the light-emitting device 3 used in this example is shown in Fig. 9B. The light-emitting device 3 used in this example is a light-emitting device with a tandem structure having two EL layers (EL layer 802a and EL layer 802b) between a pair of electrodes (first electrode 801 and second electrode 803) and a charge generation layer 816 between the two EL layers.

[0288] The specific configuration of the light emitting device 3 used in this example is shown in Table 5. The chemical formulas of the materials used in this example are shown below.

[0289] [Table 5]

[0290] [ka]

[0291] <<Creating light-emitting device 3>> The light-emitting device 3 shown in this embodiment has a structure in which, as shown in FIG. 9B, a first electrode 801 is formed on a substrate 800, an EL layer 802a (a hole injection layer 811a, a hole transport layer 812a, a light-emitting layer 813a, an electron transport layer 814a, and an electron injection layer 815a), a charge generation layer 816, and an EL layer 802b (a hole injection layer 811b, a hole transport layer 812b, a light-emitting layer 813b, an electron transport layer 814b, and an electron injection layer 815b) are sequentially laminated on the first electrode 801, and a second electrode 803 is laminated on the EL layer 802b.

[0292] First, a first electrode 801 was formed on a substrate 800. The electrode area was 4 mm 2 The dimensions of the substrate 800 were (2 mm×2 mm). A glass substrate was used as the substrate 800. The first electrode 801 was formed by depositing an alloy of silver (Ag), palladium (Pd), and copper (Cu) (Ag-Pd-Cu (APC)) with a thickness of 100 nm by a sputtering method, and ITSO was formed by depositing a film with a thickness of 10 nm by a sputtering method. In this embodiment, the first electrode 801 functions as an anode.

[0293] As a pretreatment, the surface of the substrate was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and then the substrate was allowed to cool for about 30 minutes.

[0294] Next, a hole injection layer 811a was formed on the first electrode 801. The hole injection layer 811a was formed by evaporating the solution in a vacuum deposition apparatus for 10 -4 After reducing the pressure to 10 Pa, DBT3P-II and molybdenum oxide were co-evaporated in a weight ratio of DBT3P-II:molybdenum oxide = 2:1 to form a film having a thickness of 10 nm.

[0295] Next, a hole transport layer 812a was formed on the hole injection layer 811a. The hole transport layer 812a was formed by vapor deposition using PCBBiF so as to have a film thickness of 30 nm.

[0296] Next, a light-emitting layer 813a was formed over the hole-transport layer 812a. 2mDBTBPDBq-II was used as a host material, PCBBiF was used as an assist material, and [Ir(dmdpbq) 2 (dpm)] was used, with a weight ratio of 2mDBTBPDBq-II:PCBBiF:[Ir(dmdpbq) 2 (dpm)] = 0.7:0.3:0.1. The film thickness was 40 nm.

[0297] Next, the electron transport layer 814a was formed on the light emitting layer 813a by sequentially depositing 2mDBTBPDBq-II to a thickness of 20 nm and NBphen to a thickness of 90 nm.

[0298] Next, the electron injection layer 815a was formed on the electron transport layer 814a. The electron injection layer 815a was made of lithium oxide (Li 2 O) was evaporated to a thickness of 0.1 nm.

[0299] Next, charge generation layer 816 was formed on electron injection layer 815a. Charge generation layer 816 was formed by vapor deposition using copper (II) phthalocyanine (CuPc) to a thickness of 2 nm.

[0300] Next, a hole injection layer 811b was formed on the charge generation layer 816. The hole injection layer 811b was formed by co-evaporation of DBT3P-II and molybdenum oxide in a weight ratio of DBT3P-II:molybdenum oxide=2:1 to a thickness of 10 nm.

[0301] Next, a hole transport layer 812b was formed on the hole injection layer 811b. The hole transport layer 812b was formed by vapor deposition using PCBBiF so as to have a thickness of 60 nm.

[0302] Next, a light-emitting layer 813b was formed over the hole-transport layer 812b. 2mDBTBPDBq-II was used as a host material, PCBBiF was used as an assist material, and [Ir(dmdpbq) 2 (dpm)] was used, with a weight ratio of 2mDBTBPDBq-II:PCBBiF:[Ir(dmdpbq) 2 (dpm)] = 0.7:0.3:0.1. The film thickness was 40 nm.

[0303] Next, the electron transport layer 814b was formed on the light emitting layer 813b by sequentially depositing 2mDBTBPDBq-II to a thickness of 20 nm and NBphen to a thickness of 65 nm.

[0304] Next, the electron injection layer 815b was formed on the electron transport layer 814b. The electron injection layer 815b was formed by vapor deposition using lithium fluoride (LiF) so as to have a film thickness of 1 nm.

[0305] Next, a second electrode 803 was formed on the electron injection layer 815b. The second electrode 803 was formed by co-evaporation of silver (Ag) and magnesium (Mg) at a volume ratio of Ag:Mg=10:1 to a thickness of 20 nm. In this embodiment, the second electrode 803 functions as a cathode.

[0306] Next, a buffer layer 804 was formed on the second electrode 803. The buffer layer 804 was formed by vapor deposition using DBT3P-II so as to have a film thickness of 110 nm.

[0307] Through the above steps, the light emitting device 3 was formed on the substrate 800. Furthermore, in all of the deposition steps in the above-mentioned manufacturing method, deposition using resistance heating was used.

[0308] The light emitting device 3 is sealed with another substrate (not shown). The sealing method is the same as that of the light emitting device 1, and reference can be made to Example 2.

[0309] A microcavity structure is applied to the light-emitting device 3. The light-emitting device 3 was fabricated so that the optical distance between a pair of reflective electrodes (APC film and Ag:Mg film) was approximately one wavelength of the maximum peak wavelength of the light emitted by the guest material.

[0310] <Operation characteristics of light-emitting device 3> The operating characteristics of the light emitting device 3 were measured. The measurements were carried out at room temperature (an atmosphere maintained at 25° C.).

[0311] FIG. 24 shows the current density-radiant emittance characteristics of the light-emitting device 3. FIG. 25 shows the voltage-current density characteristics of the light-emitting device 3. FIG. 26 shows the current density-radiant flux characteristics of the light-emitting device 3. FIG. 27 shows the voltage-radiant emittance characteristics of the light-emitting device 3. FIG. 28 shows the current density-external quantum efficiency characteristics of the light-emitting device 3. The radiant emittance, radiant flux, and external quantum efficiency were calculated using radiance, assuming that the light distribution characteristics of the light-emitting device are Lambertian type.

[0312] 6.8W / sr / m in Table 6 2 4 shows main initial characteristic values ​​of the light emitting device 3 in the vicinity.

[0313] [Table 6]

[0314] 24 to 28 and Table 6, it was found that the light-emitting device 3 exhibited good characteristics. Since the light-emitting device 3 had a tandem structure, it was possible to obtain results in which the peak value of the EL intensity was high and the external quantum efficiency was high.

[0315] In addition, 10 mA / cm2 was applied to the light-emitting device 3. 2FIG. 29 shows the emission spectrum when a current was passed at a current density of 1000 nm. The emission spectrum was measured using a near-infrared spectroradiometer (SR-NIR, manufactured by Topcon Corporation). As shown in FIG. 29, the light-emitting device 3 has an emission spectrum of [Ir(dmdpbq) 2 The emission spectrum showed a maximum peak at around 799 nm, which was due to the emission of [(dpm)].

[0316] In addition, by adopting a microcavity structure, the emission spectrum was narrowed to a half-width of 32 nm. The light-emitting device 3 efficiently emits light in the range of 760 nm to 900 nm (or 780 nm to 880 nm), and is therefore highly effective as a light source for sensor applications.

[0317] <Reliability test of light-emitting device 3> Next, a reliability test was conducted on the light-emitting device 3. The results of the reliability test are shown in Fig. 30. In Fig. 30, the vertical axis indicates normalized luminous intensity (%) when the initial luminous intensity is taken as 100%, and the horizontal axis indicates driving time (h). The reliability test was conducted at a current density of 75 mA / cm 2 The light emitting device 3 was driven.

[0318] The results of the reliability test showed that the light-emitting device 3 exhibited high reliability. This is because the light-emitting device 3 was fabricated using an organometallic complex, [Ir(dmdpbq) 2 This effect can be attributed to the use of the compound (structural formula (100)) in the light-emitting layer of the light-emitting device 3.

[0319] <Viewing angle characteristics of light-emitting device 3> Next, the viewing angle characteristics of the EL spectrum of the light-emitting device 3 were examined.

[0320] First, the EL spectrum of the light-emitting element in the front direction and the EL spectrum in the oblique direction were measured. Specifically, the direction perpendicular to the light-emitting surface of the light-emitting device 3 was set as 0°, and the emission spectrum was measured at a total of 17 points at 10° intervals from -80° to 80°. A multichannel spectrometer (Hamamatsu Photonics, PMA-12) was used for the measurement. From the measurement results, the EL spectrum and photon intensity ratio of the light-emitting element at each angle were obtained.

[0321] FIG. 31 shows the EL spectrum of light-emitting device 3 from 0° to 60°.

[0322] Fig. 32 shows the photon intensity (normalized photon intensity) at each angle (Angle) with respect to the photon intensity at the front in the light emitting device 3. Fig. 32 further shows the Lambertian characteristic.

[0323] As shown in Figures 31 and 32, it was found that the light-emitting device 3 has a large viewing angle dependency, and emits strong light in the front direction. This is because the use of a microcavity structure strengthens the light emission in the front direction while weakening the light emission in oblique directions. In this way, the viewing angle characteristic with strong light emission in the front direction is suitable as a light source for sensor applications such as vein sensors.

[0324] (Reference example) The bis(dibenzo[a,i]naphtho[2,1-c]phenazin-10-yl-κC) used in Example 3 above 10 ,κN 11 )(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O') Iridium(III) (abbreviation: [Ir(dbnphz) 2 The synthesis method of [Ir(dbnphz) 2 The structure of (dpm)] is shown below.

[0325] [ka]

[0326] <Step 1: Synthesis of dibenzo[a,i]naphtho[2,1-c]phenazine (abbreviation: Hdbnphz)> First, 1.0 g (4.0 mmol) of chrysene-5,6-dione, 0.67 g (4.3 mmol) of 2,3-diaminonaphthalene, and 20 mL of ethanol were placed in a reaction vessel and heated to reflux for 5 hours. After the specified time had elapsed, the resulting mixture was suction filtered and the solid was washed with ethanol. This solid was dissolved in heated toluene and suction filtered through a filter material layered in the order of Celite, alumina, and Celite. The resulting filtrate was concentrated and recrystallized in a mixed solvent of toluene and ethanol to obtain the target product (1.1 g, yield 74%). The synthesis scheme of step 1 is shown in (b-1).

[0327] [ka]

[0328] <Step 2: [Ir(dbnphz) 2 Synthesis of (dpm) Next, 1.1 g (2.9 mmol) of Hdbnphz obtained in step 1, 0.39 g (1.3 mmol) of iridium chloride hydrate, and 30 mL of dimethylformamide (DMF) were added to a reaction vessel, the atmosphere in the vessel was replaced with nitrogen, and the mixture was heated and stirred at 160°C for 7.5 hours. After a predetermined time had passed, 0.55 g (5.2 mmol) of sodium carbonate and 0.72 g (3.9 mmol) of dipivaloylmethane were added and the mixture was heated and stirred at 140°C for 14 hours. Next, this mixture was suction filtered, and the obtained solid was washed with water and ethanol.

[0329] Next, this solid was purified by silica gel column chromatography using dichloromethane as a developing solvent, and the obtained fraction was concentrated to obtain a solid, which was washed with heated toluene to obtain 133 mg of the target compound.

[0330] Next, the obtained filtrate was concentrated and purified by silica gel column chromatography using toluene as a developing solvent. Next, the obtained fraction was concentrated to obtain a solid, which was recrystallized using a mixed solvent of toluene and ethanol to obtain the target product (80 mg) (total yield 213 mg, 14% yield). The synthetic scheme of step 2 is shown in formula (b-2).

[0331] [ka]

[0332] The protons ( 1 H) was measured by nuclear magnetic resonance (NMR). The values ​​obtained are shown below. From the measurement results, [Ir(dbnphz) 2 (dpm)] was obtained.

[0333] 1 H-NMR δ(CDCl 3 ):0.52(s,18H),5.04(s,1H),6.80(d,2H),6.97(t,2H),7.48(d,2H),7.59(t,2H),7.74(t,2H),7.88(d,2H) ,7.98(t,2H),8.06(d,2H),8.10(d,2H),8.26(d,4H),8.64(d,2H),9.13(s,2H),9.19(s,2H),11.21(d,2H). [Explanation of symbols]

[0334] 101: first electrode, 102: second electrode, 103: EL layer, 103a: EL layer, 103b: EL layer, 104: charge generation layer, 111: hole injection layer, 112: hole transport layer, 113: light emitting layer, 114: electron transport layer, 115: electron injection layer, 301: first substrate, 302: pixel section, 303: circuit section, 304a: circuit section, 304b: circuit section, 305: seal material, 306: second substrate, 307: wiring, 308: FPC, 309: transistor, 310: transistor, 311: transistor, 312: transistor, 313: first electrode, 314: insulating layer, 315: EL layer, 316: second electrode, 317: organic EL device, 318: space, 401: first electrode, 402: EL layer, 403: second electrode, 405: insulating layer, 406: conductive layer, 407: adhesive layer, 416: conductive layer, 420: substrate, 422: adhesive layer, 423: barrier layer, 424: insulating layer, 450: organic EL device, 490a: substrate, 490b: substrate, 490c: barrier layer, 800: substrate, 801: first electrode, 802: EL layer, 8 802a: EL layer, 802b: EL layer, 803: second electrode, 804: buffer layer, 811: hole injection layer, 811a: hole injection layer, 811b: hole injection layer, 812: hole transport layer, 812a: hole transport layer, 812b: hole transport layer, 813: light emitting layer, 813a: light emitting layer, 813b: light emitting layer, 814: electron transport layer, 814a: electron transport layer, 814b: electron transport layer, 815: electron injection layer, 815a: electron injection layer, 815b: electron injection layer, 816: charge generation layer, 911: housing, 912: light source, 913: detector sensing stage, 914: imaging device, 915: light emitting unit, 916: light emitting unit, 917: light emitting unit, 921: housing, 922: operation button, 923: detection unit, 924: light source, 925: imaging device, 931: housing, 932: operation panel, 933: transport mechanism, 934: monitor, 935: detection unit, 936: inspected member, 937: imaging device, 938: light source, 981: housing, 982: display unit, 983: operation button, 984: external connection port, 985: speaker, 986: microphone, 987: camera, 988: camera

Claims

1. A first electrode, a second electrode, and a light-emitting layer, the light-emitting layer is located between the first electrode and the second electrode; the light-emitting layer includes a light-emitting organic compound, a first organic compound, and a second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, the luminescent organic compound is an organometallic complex having a metal-carbon bond; The organometallic complex has two to five fused heteroaromatic rings and a first benzene ring, the fused heteroaromatic ring and the first benzene ring are each coordinated to the metal; the first benzene ring is bonded to the fused heteroaromatic ring; A light-emitting device, wherein the maximum peak wavelength of light emitted by the light-emitting organic compound is 760 nm or more and 900 nm or less.

2. A first electrode, a second electrode, and a light-emitting layer, the light-emitting layer is located between the first electrode and the second electrode; the light-emitting layer includes a light-emitting organic compound, a first organic compound, and a second organic compound; the first organic compound and the second organic compound are a combination that forms an exciplex, the luminescent organic compound is an organometallic complex having a metal-carbon bond; The organometallic complex has two or more and five or less fused heteroaromatic rings, a first benzene ring, and a second benzene ring, the fused heteroaromatic ring and the first benzene ring are each coordinated to the metal; the first benzene ring and the second benzene ring are bonded to the fused heteroaromatic ring; A light-emitting device, wherein the maximum peak wavelength of light emitted by the light-emitting organic compound is 760 nm or more and 900 nm or less.

3. In claim 1 or 2, A light-emitting device, wherein the light-emitting organic compound is a cyclometal complex.

4. In any one of claims 1 to 3, A light-emitting device, wherein the luminescent organic compound is an ortho-metal complex.

5. In any one of claims 1 to 4, A light-emitting device, wherein the luminescent organic compound is an iridium complex.

6. In any one of claims 1 to 5, A light-emitting device, wherein the maximum peak wavelength of light emitted by the light-emitting organic compound is 780 nm or more and 880 nm or less.

7. A light emitting device according to any one of claims 1 to 6, A light emitting device comprising: a transistor and / or a substrate.

8. A light emitting device according to claim 7; A light emitting module having a connector and / or an integrated circuit.

9. A light emitting module according to claim 8; An electronic device having at least one of an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operation button.

10. A light emitting device according to claim 7; A lighting device having at least one of a housing, a cover, and a support base.

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