Organic compound, light-emitting element, light-emitting device, electronic device, and lighting device

Abstract

The present invention provides a novel organometallic complex. In addition, one embodiment of the present invention provides a novel organometallic complex having a high quantum yield. A ligand of the Ir complex comprises a 1H-naphtho [1, 2-d] imidazole skeleton and has a structure represented by the following general formula (G-1). Among the N groups included in the 1H-naphtho [1, 2-d] imidazole skeleton, the N group that is not bonded to Ir is bonded to a substituted or unsubstituted aryl group. In general formula (G-1), R1 to R10 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms or an electron withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

Description

This application is a divisional application of an application with an application date of July 29, 2019, an application number of "201980050982.6", and an invention title of "Organic Compound, Light-Emitting Element, Light-Emitting Device, Electronic Device, and Lighting Device". Technical Field

[0001] One aspect of the present invention relates to a novel organic compound, and particularly to an organometallic complex in which a ligand contains a 1H-naphtho[1,2-d]imidazole skeleton. In addition, one aspect of the present invention also relates to a light-emitting element, a light-emitting device, an electronic device, and a lighting device including the organometallic complex.

[0002] Note that one aspect of the present invention is not limited to the above technical field. One aspect of the present invention relates to an object, a method, or a manufacturing method. In particular, one aspect of the present invention relates to an organic compound, a light-emitting element, a light-emitting device, a lighting device, and a manufacturing method thereof. In addition, one aspect of the present invention relates to a novel synthesis method of an organometallic complex in which a ligand contains a 1H-naphtho[1,2-d]imidazole skeleton. Therefore, as a specific example of one aspect of the present invention disclosed in this specification, there can be cited a manufacturing method of a light-emitting element, a light-emitting device, a display device, an electronic device, and a lighting device containing the organometallic complex. Background Art

[0003] In recent years, the practical application of light-emitting elements (organic EL elements) using electroluminescence (EL) of organic compounds has been very active. In the basic structure of these light-emitting elements, an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes. By applying a voltage to this element, carriers are injected, and using the recombination energy of the carriers, light emission from the light-emitting material can be obtained.

[0004] Such a light-emitting element is a self-luminous type light-emitting element, and when it is used as a pixel of a display, it has advantages such as high visibility and no need for a backlight. Therefore, this light-emitting element is suitable for flat panel display elements. In addition, it is also a great advantage that a display using this light-emitting element can be manufactured to be thin and light. And an extremely fast response speed is also one of its characteristics.

[0005] Since the light-emitting layer of such a light-emitting element can be formed continuously in two dimensions, planar light emission can be obtained. This is a characteristic that is difficult to obtain in point light sources typified by incandescent lamps or LEDs or in line light sources typified by fluorescent lamps. In addition, by selecting materials, the light emission of the organic compound can be light emission that does not contain ultraviolet light, and thus it also has high utilization value as a planar light source applicable to lighting and the like.

[0006] As described above, displays or lighting devices using organic EL elements are applicable to various electronic devices, and research and development of light-emitting elements with higher efficiency and longer element life has been increasingly active. In recent years, since the luminous efficiency of phosphorescent light-emitting elements is higher than that of fluorescent light-emitting elements, research and development of phosphorescent light-emitting elements has been increasingly enhanced (for example, refer to Patent Document 1).

[0007] [Prior Art Documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-147496 Summary of the Invention Technical Problem to be Solved by the Invention

[0009] As reported in the above Patent Document 1, the development of phosphorescent materials with excellent characteristics has progressed, but the development of novel materials with even more excellent characteristics is expected. In particular, the development of blue or green phosphorescent materials with high efficiency and high reliability is expected.

[0010] Accordingly, an object of one aspect of the present invention is to provide a novel organometallic complex. Another object of one aspect of the present invention is to provide a novel organometallic complex containing a 1H-naphtho[1,2-d]imidazole skeleton. Another object of one aspect of the present invention is to provide an organometallic complex with a high quantum yield. Another object of one aspect of the present invention is to provide a light-emitting element with good luminous efficiency. Another object of one aspect of the present invention is to provide a light-emitting element with good lifespan. Another object of one aspect of the present invention is to provide a light-emitting element with good color purity. Another object of one aspect of the present invention is to provide a light-emitting element with a low driving voltage.

[0011] Another object of another aspect of the present invention is to provide a highly reliable light-emitting element, light-emitting device, and electronic device. Another object of another aspect of the present invention is to provide a low-power light-emitting element, light-emitting device, and electronic device.

[0012] Note that the description of these objects does not preclude the existence of other objects. In addition, one aspect of the present invention does not necessarily need to achieve all of the above objects. In addition, objects other than the above can be clearly seen from the description in the specification, drawings, claims, etc., and objects other than the above can be extracted from the description in the specification, drawings, claims, etc. Means for Solving the Technical Problem

[0013] One aspect of the present invention is an organometallic complex having a structure represented by the following general formula (G-1) in which a ligand contains a 1H-naphtho[1,2-d]imidazole skeleton.

[0014] [Chemical Formula 1]

[0015] In general formula (G-1), R 1 to R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0016] Furthermore, another aspect of the present invention is an organometallic complex having a structure represented by general formula (G-2).

[0017] [Chemical Formula 2]

[0018] In general formula (G-2), R 1 to R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group.

[0019] Furthermore, another aspect of the present invention is an organometallic complex having a structure represented by general formula (G-3).

[0020] [Chemical Formula 3]

[0021] In general formula (G-3), R 11 , R 13 and R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group.

[0022] Furthermore, another aspect of the present invention is an organometallic complex having a structure represented by general formula (G-4).

[0023] [Chemical Formula 4]

[0024] In general formula (G-4), R 13 represents hydrogen or an electron-withdrawing group.

[0025] Furthermore, another aspect of the present invention is an organometallic complex having a structure represented by general formula (G-5).

[0026] [Chemical Formula 5]

[0027] In general formula (G-5), R 15 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0028] In the above structure, general formula (G-1) is preferably represented by general formula (G-6).

[0029] [Chemical formula 6]

[0030] In the above structure, general formula (G-2) is preferably represented by general formula (G-7).

[0031] [Chemical formula 7]

[0032] In the above structure, general formula (G-3) is preferably represented by general formula (G-8).

[0033] [Chemical formula 8]

[0034] In the above structure, general formula (G-4) is preferably represented by general formula (G-9).

[0035] [Chemical formula 9]

[0036] In the above structure, general formula (G-5) is preferably represented by general formula (G-10).

[0037] [Chemical formula 10]

[0038] In the above structure, general formula (G-1) is preferably represented by general formula (G-11).

[0039] [Chemical formula 11]

[0040] In general formula (G-11), L represents a monoanionic ligand, and n represents 1 or 2.

[0041] In the above structure, general formula (G-2) is preferably represented by general formula (G-12).

[0042] [Chemical formula 12]

[0043] In general formula (G-12), L represents a monoanionic ligand, and n represents 1 or 2.

[0044] In the above structure, general formula (G-3) is preferably represented by general formula (G-13).

[0045] [Chemical formula 13]

[0046] In general formula (G-13), L represents a monoanionic ligand, and n represents 1 or 2.

[0047] In the above structure, general formula (G-4) is preferably represented by general formula (G-14).

[0048] [Chemical formula 14]

[0049] In general formula (G-14), L represents a monoanionic ligand, and n represents 1 or 2.

[0050] In the above structure, general formula (G-5) is preferably represented by general formula (G-15).

[0051] [Chemical formula 15]

[0052] In general formula (G-15), L represents a monoanionic ligand, and n represents 1 or 2.

[0053] In general formulas (G-3), (G-8), and (G-13), R 11 and R 15 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, and R 13 represents hydrogen or an electron-withdrawing group.

[0054] In addition, in the above structure, the electron-withdrawing group is preferably any one of a halogenated group, a cyano group, and a trifluoromethyl group.

[0055] In addition, in the above structure, the alkyl group is preferably a branched alkyl group having 3 to 6 carbon atoms.

[0056] In addition, in the above structure, the monoanionic ligand is preferably a monoanionic bidentate chelating ligand having a β-diketone structure, a monoanionic bidentate chelating ligand having a carboxyl group, a monoanionic bidentate chelating ligand having a phenolic hydroxyl group, or a monoanionic bidentate chelating ligand in which both coordination elements are nitrogen, or a bidentate ligand that forms an iridium and metal-carbon bond through cyclometalation.

[0057] Furthermore, in the above structure, the monoanionic ligand is preferably any one of the following general formulas (L1) to (L9).

[0058] [Chemical Formula 16]

[0059] In general formulas (L1) to (L9), R 21 to R 86 each independently represents hydrogen or a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogenated group, a vinyl group, a cyano group, a substituted or unsubstituted halogenated alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or 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. Further, A 1 to A 13 each independently represents nitrogen, or an sp 2 hybridized carbon bonded to hydrogen, or an sp 2 hybridized carbon having a substituent, and the substituent represents any of an alkyl group having 1 to 6 carbon atoms, a halogenated group, a halogenated alkyl group having 1 to 6 carbon atoms, and a phenyl group.

[0060] Further, another aspect of the present invention is any one of the organic compounds represented by the following structural formulas (100) to (103).

[0061] [Chemical Formula 17]

[0062] Further, another aspect of the present invention is a light-emitting element including an EL layer between a pair of electrodes, wherein the EL layer contains the organic compound described in each of the above structures. The organic compound is preferably contained in the light-emitting layer in the EL layer.

[0063] Further, the light-emitting element having the above structure includes an EL layer between an anode and a cathode. Preferably, the EL layer at least includes a light-emitting layer. The EL layer may further include a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, or other functional layers.

[0064] In addition, another aspect of the present invention is a display device, including: a light-emitting element having the above structure; and at least one of a color filter and a transistor. Another aspect of the present invention is an electronic device, including: the display device; and at least one of a housing and a touch sensor. Another aspect of the present invention is a lighting device, including: a light-emitting element having the above structure; and at least one of a housing and a touch sensor. In addition, one aspect of the present invention not only includes a light-emitting device having a light-emitting element within its scope, but also includes an electronic device having a light-emitting device. Therefore, the light-emitting device in this specification refers to an image display device or a light source (including a lighting device). In addition, the following display modules are also aspects of the present invention: a display module in which a connector such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package) is mounted in a light-emitting element; a display module in which a printed circuit board is provided at an end of the TCP; or a display module in which an IC (integrated circuit) is directly mounted on a light-emitting element by a COG (Chip On Glass) method. Effects of the Invention

[0065] According to one aspect of the present invention, a novel organometallic complex can be provided. In addition, according to one aspect of the present invention, a novel organometallic complex containing a 1H-naphtho[1,2-d]imidazole skeleton can be provided. In addition, according to one aspect of the present invention, an organometallic complex with a high quantum yield can be provided. In addition, according to one aspect of the present invention, a light-emitting element with good luminous efficiency can be provided. In addition, according to one aspect of the present invention, a light-emitting element with good lifespan can be provided. In addition, according to one aspect of the present invention, a light-emitting element with good color purity can be provided. In addition, according to one aspect of the present invention, a light-emitting element with a low driving voltage can be provided.

[0066] In addition, through another aspect of the present invention, a light-emitting element, a light-emitting device, and an electronic device with high reliability can be provided. In addition, through another aspect of the present invention, a light-emitting element, a light-emitting device, and an electronic device with low power consumption can be provided.

[0067] Note that the description of these effects does not preclude the existence of other effects. Note that one aspect of the present invention does not necessarily achieve all of the above effects. In addition, effects other than the above can be clearly seen from the descriptions in the specification, drawings, and claims, and effects other than the above can be extracted from the descriptions in the specification, drawings, and claims. Brief Description of the Drawings

[0068] [Figure 1] Figure 1A andFigure 1B Schematic diagram of a light-emitting element according to one embodiment of the present invention. Figure 1C Diagram showing the energy levels of a light-emitting element according to one embodiment of the present invention. Figure 2 Figure 2 Schematic diagram of a light-emitting element according to one embodiment of the present invention. [Figure 3] Figure 3A and Figure 3B Schematic diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 4] Figure 4A and Figure 4B Schematic diagram of an active matrix light-emitting device according to one embodiment of the present invention. Figure 5 Figure 5 Schematic diagram of an active matrix light-emitting device according to one embodiment of the present invention. [Figure 6] Figures 6A to 6D Diagram showing an electronic device according to one embodiment of the present invention. [Figure 7] Figures 7A to 7E Diagram showing an electronic device according to one embodiment of the present invention. [Figure 8] Figures 8A to 8C Diagram showing an electronic device according to one embodiment of the present invention. [Figure 9] Figure 9A and Figure 9B Diagram showing an electronic device according to one embodiment of the present invention. [Figure 10] Figures 10A to 10C Diagram showing a lighting device according to one embodiment of the present invention. Figure 11 Figure 11 Diagram showing a lighting device according to one embodiment of the present invention. Figure 12 Figure 12 Diagram explaining the NMR spectrum of a compound according to an example. Figure 13 Figure 13 Diagram explaining the absorption spectrum and emission spectrum of a compound according to an example. Figure 14 Figure 14 Diagram explaining the NMR spectrum of a compound according to an example. Figure 15 Figure 15 Diagram explaining the absorption spectrum and emission spectrum of a compound according to an example. Figure 16 Figure 16 Diagram explaining the absorption spectrum and emission spectrum of a compound according to an example.​​​​​​​​​​​​​​​​ Figure 17 Figure 17 This is a diagram showing the NMR spectrum of the compound according to the embodiment. Figure 18 Figure 18 This is a diagram showing the absorption spectrum and emission spectrum of the compound according to the embodiment. Figure 19 Figure 19 This is a diagram showing the current efficiency - luminance characteristics of the light - emitting element according to the embodiment. Figure 20 Figure 20 This is a diagram showing the current density - voltage characteristics of the light - emitting element according to the embodiment. Figure 21 Figure 21 This is a diagram showing the external quantum efficiency - luminance characteristics of the light - emitting element according to the embodiment. Figure 22 Figure 22 This is a diagram showing the emission spectrum of the light - emitting element according to the embodiment. Figure 23 Figure 23 This is a diagram showing the current efficiency - luminance characteristics of the light - emitting element according to the embodiment. Figure 24 Figure 24 This is a diagram showing the current density - voltage characteristics of the light - emitting element according to the embodiment. Figure 25 Figure 25 This is a diagram showing the external quantum efficiency - luminance characteristics of the light - emitting element according to the embodiment. Figure 26 Figure 26 This is a diagram showing the emission spectrum of the light - emitting element according to the embodiment. Figure 27 Figure 27 This is a diagram showing the reliability test results of the light - emitting element according to the embodiment. Figure 28 Figure 28 This is a diagram showing the current efficiency - luminance characteristics of the light - emitting element according to the embodiment. Figure 29 Figure 29 This is a diagram showing the current density - voltage characteristics of the light - emitting element according to the embodiment. Figure 30 Figure 30 This is a diagram showing the external quantum efficiency - luminance characteristics of the light - emitting element according to the embodiment. Figure 31 Figure 31 This is a diagram showing the emission spectrum of the light - emitting element according to the embodiment. ​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​Mode of Implementing the Invention

[0069] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, those of ordinary skill in the art can easily understand the fact that the present invention can be implemented in multiple different forms, and its mode and detailed content can be transformed into various forms without departing from the gist and scope of the present invention. Therefore, the present invention should not be construed as being limited only to the content described in the embodiments.

[0070] In addition, in each of the drawings described in this specification, sometimes for the convenience of explanation, the sizes or thicknesses of the anode, EL layer, intermediate layer, cathode, etc. are exaggerated. Therefore, each component is not limited to the size shown in the drawings, nor is it limited to the relative sizes between the components.

[0071] Note that in this specification and the like, for convenience, ordinal numbers such as first, second, and third are added, and they do not represent the order of processes or the positional relationship above and below, etc. Therefore, for example, "first" can be appropriately replaced with "second" or "third" for explanation. In addition, sometimes the ordinal numbers described in this specification and the like are inconsistent with the ordinal numbers used to specify a mode of the present invention.

[0072] In addition, in the structure of the present invention described in this specification and the like, the same reference numerals are used commonly between different drawings to represent the same part or parts having the same function, and the repeated description thereof is omitted. In addition, sometimes the same hatching is used to represent parts having the same function, and no reference numerals are particularly added.

[0073] In addition, in this specification, "film" and "layer" can be interchanged according to circumstances or states. For example, sometimes "conductive layer" can be interchanged with "conductive film". Or, sometimes "insulating film" can be interchanged with "insulating layer".

[0074] (Embodiment 1) In this embodiment, an organometallic complex of a mode of the present invention will be described.

[0075] An organometallic complex of a mode of the present invention has a structure represented by the following general formula (G-1).

[0076] [Chemical Formula 18]

[0077] In the general formula (G-1), R 1 to R 10Each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0078] In the organometallic complex of one embodiment of the present invention, the ligand contains a 1H-naphtho[1,2-d]imidazole skeleton. By adopting this structure, when the organometallic complex is applied to a light-emitting element, a light-emitting element with good luminous efficiency and / or reliability can be obtained.

[0079] The ligand included in the organometallic complex of one embodiment of the present invention has a structure in which a benzene ring contained in a benzimidazole skeleton is further fused with a benzene ring. By adopting this structure, the molecular stability can be improved and a light-emitting element with good reliability can be obtained. In addition, an organometallic complex with good photoluminescence quantum yield can be obtained.

[0080] Furthermore, when a substituted or unsubstituted aryl group having 6 to 25 carbon atoms is bonded to the 1-position of the 1H-naphtho[1,2-d]imidazole skeleton, the molecular stability and sublimability are improved compared with the case where hydrogen or an alkyl group is bonded to the 1-position. Therefore, a light-emitting element with good reliability can be obtained. In addition, when manufacturing an organic EL element by a vacuum evaporation method, the organic compound of one embodiment of the present invention can be appropriately used.

[0081] <Fusion position of imidazole skeleton and naphthalene skeleton> In addition, the 1H-naphtho[1,2-d]imidazole skeleton contained in the organometallic complex of one embodiment of the present invention can be regarded as a structure in which an imidazole skeleton is fused with a naphthalene skeleton. Here, when the naphthalene skeleton is fused to the α-position of the imidazole skeleton, an Ir complex having a structure represented by the following general formula (I-1) can be considered as an example.

[0082] [Chemical formula 19]

[0083] In the general formula (I-1), R 1 to R 7 Each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0084] The structure represented by the general formula (I-1) has a structure in which an imidazole skeleton bonded to Ir and a benzene skeleton bonded to Ir are fused with each other. This structure has a tendency to have a consistently high quantum yield. In addition, since the imidazole skeleton bonded to Ir and the benzene skeleton bonded to Ir are fused, it can be predicted that luminescence will occur on the longer wavelength side compared to the case where they are not fused. Therefore, it can be predicted that this skeleton is not suitable for blue or green phosphorescent materials with particularly high research and development demands.

[0085] On the other hand, the 1H-naphtho[1,2-d]imidazole skeleton included in the organometallic complex of one aspect of the present invention has a structure in which a naphthalene skeleton is fused to the d-position of the imidazole skeleton. Here, when a naphthalene skeleton is fused to the d-position of the imidazole skeleton, 1H-naphtho[1,2-d]imidazole skeleton and 1H-naphtho[2,1-d]imidazole skeleton can be considered depending on the difference in the fusion position. By molecular orbital calculation, the influence of the difference in these fused carbons on the quantum yield was investigated.

[0086] <Calculation examples of net charge> This calculation example specifically illustrates calculation examples of the lowest triplet excited state (T1 state) of Compound-A, which is a compound modeled on the organometallic complex having a 1H-naphtho[1,2-d]imidazole skeleton of one aspect of the present invention, and Compound-B, which is a compound modeled on the organometallic complex having a 1H-naphtho[2,1-d]imidazole skeleton as a comparison object. The structures of Compound-A and Compound-B are shown below. In Compound-A, the benzene ring of a shown in the structural formula is fused to the side opposite to Ir when viewed from N (nitrogen) bonded to Ir. On the other hand, in Compound-B, the benzene ring of b shown in the structural formula is fused to the same side as Ir when bonded to N (nitrogen) to Ir. When the 1H-naphtho[2,1-d]imidazole skeleton is used as a ligand for the Ir complex, the benzene ring is fused in the same direction as Compound-B.

[0087] [Chemical formula 20]

[0088] The molecular orbital calculation uses the Gaussian09 program. B3PW91 is used as the exchange-correlation functional to perform structure optimization and vibration calculation. For the basis function, LANL2DZ is used for Ir, and 6-311G is used for other elements.

[0089] In Compound-A, the net charge on Ir in the optimized structure obtained by calculation is 0.30, while in Compound-B, the net charge is 0.20.

[0090] The result that the net charge of Ir in Compound - A is significantly higher than that in Compound - B is obtained. Metal - Ligand Charge Transfer (MLCT: metal - ligand charge transfer) is the transfer contributed by the 5d orbital of Ir and the π of the ligand. ＊ As one of the reasons for the high MLCT property, it can be cited that the net charge of Ir in the excited state is high. From this, it can be known that the MLCT property of Compound - A, which is a model of the organometallic complex of one embodiment of the present invention, in the excited state is higher than that of Compound - B. It is known that there is a correlation between the MLCT property and the quantum yield of the phosphorescent material, and it is predicted that the luminescence quantum yield is also high when the MLCT property is high. Therefore, the organic compound of one embodiment of the present invention has a high luminescence quantum yield.

[0091] In Compound - B, the benzene ring represented by b in the structural formula exists in the direction that causes steric hindrance with Ir. Therefore, it is predicted that the bond distance between Ir and N (nitrogen) in the imidazole skeleton becomes longer in Compound - B. From this, it can be considered that, as described above, the net charge on Ir in Compound - B becomes smaller. Since the Ir complex having a 1H - naphtho[2,1 - d]imidazole skeleton also has the benzene ring represented by b in the structural formula, it can be considered that its net charge is as small as that of Compound - B. On the other hand, the benzene ring represented by a in the structural formula of Compound - A does not cause steric hindrance with Ir. Therefore, it can be considered that the result of its net charge being larger than that of Compound - B can be obtained.

[0092] Thus, when considering an organometallic complex having a structure in which an imidazole skeleton is fused with a naphthalene skeleton, by adopting a 1H - naphtho[1,2 - d]imidazole skeleton, an organometallic complex with good luminescence quantum yield can be obtained.

[0093] The aryl group having 6 to 25 carbon atoms is preferably a substituted or unsubstituted phenyl group. By adopting this structure, the organometallic complex of one embodiment of the present invention can be synthesized inexpensively or easily. Therefore, the general formula (G - 1) is preferably a structure represented by the following general formula (G - 2).

[0094] [Chemical formula 21]

[0095] In the general formula (G - 2), R 1 to R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron - withdrawing group.

[0096] In addition, the organometallic complex of one embodiment of the present invention has a structure represented by the following general formula (G - 3).

[0097] [Chemical formula 22]

[0098] In the general formula (G-3), R 11 , R 13 and R 15 Each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron withdrawing group.

[0099] In the general formulas (G-2) and (G-3), R 11 and R 15 At least one of them is preferably an alkyl group having 1 to 6 carbon atoms. Since a material with high sublimability can be realized by adopting this structure, the material utilization efficiency can be improved when a light-emitting element is manufactured by vacuum evaporation. 11 and R 15 The bonded phenyl group is R 11 and R 15 When at least one of the alkyl groups is an alkyl group having 1 to 6 carbon atoms, the steric hindrance of the alkyl group causes the dihedral angle formed by the phenyl group and the 1H-naphtho[1,2-d]imidazole skeleton to become larger. Therefore, the conjugation between the phenyl group and the 1H-naphtho[1,2-d]imidazole skeleton is not easy to diffuse, thereby making the luminous wavelength short-wavelength. In addition, the alkyl group is more preferably a branched alkyl group having 3 to 7 carbon atoms. If it is a branched alkyl group, the above-mentioned effect can be obtained. As the branched alkyl group, isopropyl, isobutyl, tert-butyl, etc. can be cited.

[0100] Therefore, the organometallic complex according to one embodiment of the present invention has a structure represented by the following general formula (G-4).

[0101] [Chemical formula 23]

[0102] In the general formula (G-4), R 13 represents hydrogen or an electron-withdrawing group.

[0103] In the general formula (G-4), R 13 When hydrogen is used, the synthesis becomes easier, so it is preferred. 13When it is an electron-withdrawing group, it can lower the LUMO (Lowest Unoccupied Molecular Orbital, also known as the lowest unoccupied molecular orbital) energy level and the HOMO (Highest Occupied Molecular Orbital, also known as the highest occupied molecular orbital) energy level of the organometallic complex. Therefore, when the organometallic complex is used as a light-emitting element, the electron injection property can be improved while maintaining the hole injection property, thereby improving the luminous efficiency. In addition, an improvement in CT (Charge Transfer) property and a broadening of the spectral width can be expected. Thereby, a light-emitting element with high color rendering properties can be manufactured.

[0104] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the general formula (G-5).

[0105] [Chemical formula 24]

[0106] In the general formula (G-5), R 15 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0107] As described above, by introducing a cyano group, which is an electron-withdrawing group, at the 4-position of the phenyl group bonded to the 1-position of 1H-naphtho[1,2-d]imidazole, a light-emitting element with good luminous efficiency can be manufactured. In addition, a light-emitting element with high color rendering properties can be manufactured.

[0108] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the following general formula (G-6).

[0109] [Chemical formula 25]

[0110] In the general formula (G-6), R 1 to R 10 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0111] The organometallic complex represented by the general formula (G-6) shows a tridentate ligand in the organometallic complex represented by the general formula (G-1), and the three ligands of the organometallic complex are the same. Since the tridentate ligand organometallic complex has good luminous efficiency and reliability, it is preferred.

[0112] In addition, the organometallic complex according to one embodiment of the present invention is an organometallic complex represented by the following general formula (G-7).

[0113] [Chemical formula 26]

[0114] In the general formula (G-7), R 1 to R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group.

[0115] The organometallic complex represented by the general formula (G-7) represents a tridentate ligand in the organometallic complex represented by the general formula (G-2), wherein the three ligands of the organometallic complex are the same. The organometallic complex with a tridentate ligand has good luminous efficiency and reliability, so it is preferred.

[0116] In addition, the organometallic complex according to one embodiment of the present invention is an organometallic complex represented by the following general formula (G-8).

[0117] [Chemical formula 27]

[0118] In the general formula (G-8), R 11 , R 13 and R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group.

[0119] The organometallic complex represented by the general formula (G-8) represents a tridentate ligand in the organometallic complex represented by the general formula (G-3), wherein the three ligands of the organometallic complex are the same. The organometallic complex with a tridentate ligand has good luminous efficiency and reliability, so it is preferred.

[0120] In addition, the organometallic complex according to one embodiment of the present invention is an organometallic complex represented by the following general formula (G-9).

[0121] [Chemical formula 28]

[0122] In the general formula (G-9), R 13 represents hydrogen or an electron-withdrawing group.

[0123] The organometallic complex represented by the general formula (G-9) represents a tridentate ligand in the organometallic complex represented by the general formula (G-4), where the three ligands of the organometallic complex are the same. The organometallic complex with a tridentate ligand has good luminescence efficiency and reliability, so it is preferred.

[0124] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the following general formula (G-10).

[0125] [Chemical formula 29]

[0126] In the general formula (G-10), R 15 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0127] The organometallic complex represented by the general formula (G-10) represents a tridentate ligand in the organometallic complex represented by the general formula (G-5), where the three ligands of the organometallic complex are the same. The organometallic complex with a tridentate ligand has good luminescence efficiency and reliability, so it is preferred.

[0128] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the following general formula (G-11).

[0129] [Chemical formula 30]

[0130] In the general formula (G-11), R 1 to R 10 each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, L represents a monoanionic ligand, and n represents 1 or 2.

[0131] The organometallic complex represented by the general formula (G-11) shows a heteromer in the organometallic complex represented by the general formula (G-1), and the heteromer includes two or more ligands. The organometallic complex of the heteromer can adjust the luminescence color or sublimability by selecting the ligand combination, so it is preferred.

[0132] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the following general formula (G-12).

[0133] [Chemical formula 31]

[0134] In the general formula (G-12), R 1 to R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, L represents a monoanionic ligand, and n represents 1 or 2.

[0135] The organometallic complex represented by the general formula (G-12) shows a heteromer in the organometallic complex represented by the general formula (G-2), and the heteromer includes two or more ligands. The organometallic complex of the heteromer can adjust the luminescent color or sublimability by selecting the ligand combination, so it is preferred.

[0136] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the following general formula (G-13).

[0137] [Chemical formula 32]

[0138] In the general formula (G-13), R 11 , R 13 and R 15 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, L represents a monoanionic ligand, and n represents 1 or 2.

[0139] The organometallic complex represented by the general formula (G-13) shows a heteromer in the organometallic complex represented by the general formula (G-3), and the heteromer includes two or more ligands. The organometallic complex of the heteromer can adjust the luminescent color or sublimability by selecting the ligand combination, so it is preferred.

[0140] In addition, the organometallic complex of one embodiment of the present invention is an organometallic complex represented by the following general formula (G-14).

[0141] [Chemical formula 33]

[0142] In the general formula (G-14), R 13 represents hydrogen or an electron-withdrawing group, L represents a monoanionic ligand, and n represents 1 or 2.

[0143] The organometallic complex represented by the general formula (G-14) shows a heteromer in the organometallic complex represented by the general formula (G-4), and the heteromer includes two or more ligands. The organometallic complex of the heteromer can adjust the luminescent color or sublimability by selecting the ligand combination, so it is preferable.

[0144] In addition, the organometallic complex of one aspect of the present invention is an organometallic complex represented by the following general formula (G-15).

[0145] [Chemical formula 34]

[0146] In the general formula (G-15), R 15 represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, L represents a monoanionic ligand, and n represents 1 or 2.

[0147] The organometallic complex represented by the general formula (G-15) shows a heteromer in the organometallic complex represented by the general formula (G-5), and the heteromer includes two or more ligands. The organometallic complex of the heteromer can adjust the luminescent color or sublimability by selecting the ligand combination, so it is preferable.

[0148] In addition, the monoanionic ligand represented by L in the above general formulas (G-11) to (G-15) is preferably a bidentate chelating ligand of a monoanion containing a β-diketone structure, a bidentate chelating ligand of a monoanion containing a carboxyl group, a bidentate chelating ligand of a monoanion containing a phenolic hydroxyl group, or a bidentate chelating ligand of a monoanion in which both coordination elements are nitrogen, or a bidentate ligand that forms a metal-carbon bond with iridium due to cyclometalation. Specifically, any one of the following general formulas (L1) to (L9) is preferable.

[0149] [Chemical formula 35]

[0150] In addition, in the above general formulas (L1) to (L9), R 21 to R 86 each independently represent the following: hydrogen; a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; a halogenated group; vinyl; cyano; 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; and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. In addition, A 1 to A 13 each independently represent sp 2 hybridized carbon bonded to nitrogen or hydrogen, or sp with a substituent2 Hybrid carbon, and the substituent represents any one of an alkyl group having 1 to 6 carbon atoms, a halogenated group, a halogenated alkyl group having 1 to 6 carbon atoms, and a phenyl group.

[0151] Here, although the organometallic complex of the heterostructure includes a plurality of ligands, the HOMO and LUMO of the organometallic complex are preferably distributed in the same ligand. When adopting this structure, an organometallic complex with particularly good luminous efficiency can be realized. Therefore, in the general formulas (G-11) to (G-15), L is particularly preferably (L8) or (L9). The organometallic complex of one embodiment of the present invention includes an imidazole skeleton of a 5-membered ring. Therefore, L also preferably has a structure including a 5-membered ring skeleton. By adopting this structure, the HOMO and LUMO possessed by the organometallic complex are easily distributed in the same ligand.

[0152] <Examples of substituents> In the general formulas (G-1) to (G-15), R 1 to R 15 For example, it represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group. As the alkyl group, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl, etc. can be cited. As the cycloalkyl group, for example, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. can be cited. As the aryl group, phenyl, naphthyl, biphenyl, fluorene group, spirofluorene group, etc. can be cited. As the electron-withdrawing group, a halogenated group, a cyano group, a nitro group, a carbonyl group, a halogenated alkyl group can be cited. As a specific example of the halogenated alkyl group, trifluoromethyl, etc. can be particularly cited. More specifically, for example, groups represented by the following structural formulas (R-1) to (R-43) can be cited. In particular, the halogenated group, the cyano group, and the trifluoromethyl group have high electron-withdrawing properties and high stability, so they are preferred. In addition, the groups represented by R 1 to R 4 and R 5 to R 13 are not limited to this.

[0153] [Chemical formula 36]

[0154] At this time, when R 1 to R 10 is hydrogen, the organometallic complex of one embodiment of the present invention can be synthesized simply and inexpensively. This organometallic complex is electrochemically stable and has high reliability, so it is preferred. In addition, when R 1 to R 10When it is a substituent other than hydrogen, the heat resistance of the organometallic complex of one embodiment of the present invention can be improved. As in (R-2) to (R-15), when it is an alkyl group or a cycloalkyl group, the solubility in an organic solvent is improved, and thus the purification of the organometallic complex of one embodiment of the present invention is facilitated. As in (R-16), (R-22) to (R-28), (R-31), and (R-32), an aryl group having no alkyl group and cycloalkyl group is electrochemically stable and has high reliability.

[0155] In addition, in the general formulas (G-1), (G-6), and (G-11), examples of the substituted or unsubstituted aryl group having 6 to 25 carbon atoms include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, a spirofluorenyl group, etc. Specifically, groups represented by the following structural formulas (Ar-1) to (Ar-25) can be used. Note that the group represented by Ar is not limited thereto. In addition, it may have a substituent.

[0156] [Chemical formula 37]

[0157] In addition, in the above general formulas (L1) to (L9), as R 21 to R 86 are each independently exemplified as follows: hydrogen; a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms; a halogenated group; vinyl; cyano; a substituted or unsubstituted halogenated alkyl 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; and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a tert-butyl group, a n-hexyl group, etc. Examples of the halogenated group include a fluoro group, a chloro group, a bromo group, an iodo group, etc. Examples of the vinyl group include vinyl and vinyl acetate. Examples of the halogenated alkyl group include a trifluoromethyl group, a pentafluoroethyl group, and a trichloromethyl group. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a phenoxy group. Examples of the alkylthio group include a propylthio group and a butylthio group. Examples of the aryl group include a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, etc. More specifically, groups represented by the following structural formulas (R-50) to (R-95) can be exemplified. Note that the group represented by R 21 to R 86 is not limited thereto.

[0158] [Chemical formula 38]

[0159] In the above general formulas (G1) to (G15), in Ar, R 1 to R 15 and R 21 to R86 In the case where there are also substituents, examples of such substituents include alkyl groups having 1 to 6 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 7 carbon atoms, or substituted or unsubstituted aryl groups having 6 to 25 carbon atoms. Examples of the alkyl group include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, n-hexyl, etc. Examples of the above cycloalkyl group include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Examples of the above aryl group include phenyl, naphthyl, fluorenyl, etc.

[0160] <Specific examples of the compound> As specific structures of the compounds represented by the general formulas (G-1) to (G-15), organometallic complexes represented by the following structural formulas (100) to (123) and structural formulas (200) to (223) can be cited. Note that the organometallic complexes represented by the general formulas (G-1) to (G-15) are not limited to the following examples.

[0161] [Chemical formula 39]

[0162] [Chemical formula 40]

[0163] [Chemical formula 41]

[0164] [Chemical formula 42]

[0165] [Chemical formula 43]

[0166] [Chemical formula 44]

[0167] [Chemical formula 45]

[0168] In addition, the organometallic complexes in one aspect of the present invention can be formed by methods such as vapor deposition methods (including vacuum vapor deposition methods), inkjet methods, coating methods, gravure printing, etc.

[0169] In addition, this embodiment can be appropriately combined with other embodiments.

[0170] (Embodiment 2)

[0171] In this embodiment, an example of a method for synthesizing an organometallic complex of one aspect of the present invention will be described.

[0172] Synthesis method of 1H-naphtho[1,2-d]imidazole derivative represented by general formula (g-1) An example of the synthesis method of the 1H-naphtho[1,2-d]imidazole derivative represented by the following general formula (g-1) is described. An organometallic complex of one embodiment of the present invention having a structure represented by the general formula (G-1) contains the 1H-naphtho[1,2-d]imidazole derivative represented by the general formula (g-1) as a ligand. Therefore, by synthesizing an Ir complex using the 1H-naphtho[1,2-d]imidazole derivative represented by the general formula (g-1), an organometallic complex of one embodiment of the present invention can be synthesized as described later.

[0173] [Chemical formula 46]

[0174] In general formula (g-1), R 1 to R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0175] As shown in the following scheme (S-1), a 1H-naphtho[1,2-d]imidazole derivative represented by the general formula (g-1) can be obtained by the reaction of an aryl aldehyde compound or an aryl carboxylic acid chloride (M1) and an o-naphthylenediamine derivative (M2) substituted with Ar at the N position.

[0176] [Chemical formula 47]

[0177] In scheme (S-1), R 1 to R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0178] Synthesis method of organometallic complex represented by general formula (G-6) Next, an example of the synthesis method of the organometallic complex represented by the general formula (G-6) in the synthesis method of the organometallic complex having a structure represented by the general formula (G-1) is described.

[0179] As shown in the following Scheme (S-2), after heating a 1H-naphthyl[1,2-d]imidazole derivative represented by the general formula (g-1) and an iridium metal compound containing a halogen (such as iridium chloride hydrate, ammonium hexachloroiridate, etc.) or an iridium organometallic complex compound (such as an acetylacetonate complex, a diethyl sulfide complex, etc.), an organometallic complex having a structure represented by the general formula (G-6) can be obtained. In addition, this heating step can also be carried out after dissolving the 1H-naphthyl[1,2-d]imidazole derivative represented by the general formula (g-1), the iridium metal compound containing a halogen or the iridium organometallic complex compound in an alcohol solvent (such as glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.). In addition, in Scheme (S-2), R 1 to R 10 each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0180] [Chemical formula 48]

[0181] Note that the method for synthesizing the organometallic complex of the present invention is not limited to Scheme (S-2).

[0182] <Synthesis method of the organometallic complex represented by the general formula (G-11)> Next, an example of the synthesis method of the organometallic complex represented by the general formula (G-11) in the synthesis method of the organometallic complex including the structure represented by the general formula (G-1) will be described.

[0183] As shown in the following Scheme (S-3), without using a solvent, using only an alcohol solvent (such as glycerol, ethylene glycol, 2-methoxyethanol, 2-ethoxyethanol, etc.) or using a mixed solvent of one or more alcohol solvents and water and in an inert gas atmosphere, heating the 1H-naphthyl[1,2-d]imidazole derivative represented by the general formula (g-1) or L obtained by the above synthesis scheme (g-1) and an iridium compound containing a halogen (such as iridium chloride, iridium bromide, iridium iodide, etc.) can obtain a binuclear complex (P1) of the 1H-naphthyl[1,2-d]imidazole derivative or a binuclear complex (P2) containing a monoanionic bidentate ligand. Both the binuclear complex (P1) and the binuclear complex (P2) are organometallic complexes having a structure crosslinked by a halogen as a novel substance. In addition, in Scheme (S-3), X represents a halogen atom, and R 1 to R 10Each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0184] [Chemical formula 49]

[0185] Furthermore, as shown in the following scheme (S-4), in an inert gas atmosphere, the binuclear complex (P1) or (P2) obtainable by the above synthesis scheme (S-3) and a 1H-naphtho[1,2-d]imidazole derivative or L represented by the general formula (g-1) are reacted to obtain an organometallic complex of one embodiment of the present invention represented by the general formula (G-11). Here, furthermore, by irradiating light or heating the obtained organometallic complex to cause it to react, isomers such as geometric isomers and optical isomers can also be obtained, and they are also organometallic complexes of one embodiment of the present invention represented by the general formula (G-11). In addition, in the scheme (S-4), X represents a halogen atom, and R 1 to R 10 Each independently represents hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, or an electron-withdrawing group, and Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

[0186] [Chemical formula 50]

[0187] Note that the synthesis method of the organometallic complex of the present invention is not limited to the schemes (S-3) and (S-4).

[0188] (Embodiment 3) In the present embodiment, a light-emitting element including an organometallic complex of one embodiment of the present invention will be described with reference to FIG. 1.

[0189] <Structural example 1 of the light-emitting element> First, the following will be described with reference to Figure 1A , Figure 1B , Figure 1C the structure of a light-emitting element of one embodiment of the present invention.

[0190] Figure 1A is a cross-sectional schematic view of a light-emitting element 150 of one embodiment of the present invention.

[0191] The light-emitting element 150 includes a pair of electrodes (electrode 101 and electrode 102), and includes an EL layer 100 disposed between the pair of electrodes. The EL layer 100 includes at least a light-emitting layer 140.

[0192] In addition, Figure 1A The EL layer 100 shown includes functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 118, and an electron injection layer 119 in addition to the light-emitting layer 140.

[0193] Note that although in this embodiment, electrode 101 of the pair of electrodes is used as the anode and electrode 102 is used as the cathode for description, the structure of the light-emitting element 150 is not limited thereto. That is, electrode 101 can also be used as the cathode and electrode 102 can be used as the anode, and the layers between the electrodes can be stacked in reverse order. In other words, the hole injection layer 111, the hole transport layer 112, the light-emitting layer 140, the electron transport layer 118, and the electron injection layer 119 can be stacked in sequence from the anode side.

[0194] Note that the structure of the EL layer 100 is not limited to Figure 1A the structure shown, as long as it includes at least one selected from the hole injection layer 111, the hole transport layer 112, the electron transport layer 118, and the electron injection layer 119. Alternatively, the EL layer 100 can also include a functional layer having the following functions: capable of reducing the injection barrier of holes or electrons; capable of improving the transportability of holes or electrons; capable of hindering the transportability of holes or electrons; or capable of suppressing the quenching phenomenon caused by the electrodes, etc. The functional layer can be either a single layer or a structure in which multiple layers are stacked.

[0195] In the light-emitting element 150, any layer in the EL layer 100 may contain an organometallic complex according to one aspect of the present invention. In addition, the organometallic complex has a good quantum yield. Therefore, by using the organometallic complex as the guest material of the light-emitting layer 140, a light-emitting element with good luminous efficiency can be obtained.

[0196] Figure 1B is a cross-sectional schematic diagram showing Figure 1A an example of the light-emitting layer 140 shown. Figure 1B The light-emitting layer 140 shown includes a host material 141 and a guest material 142. The host material 141 can be composed of one organic compound or can be a co-host type including organic compound 141_1 and organic compound 141_2. The organometallic complex according to one aspect of the present invention can be appropriately used as the guest material 142.

[0197] As the guest material 142, a light-emitting organic material can be used. As the light-emitting organic material, a material capable of emitting fluorescence (hereinafter, also referred to as a fluorescent material) or a material capable of emitting phosphorescence (hereinafter, also referred to as a phosphorescent compound) can be cited. A phosphorescent material is preferably used because of its high luminous efficiency. Thus, an organometallic complex according to one embodiment of the present invention can be appropriately used. Hereinafter, a structure in which a phosphorescent material is used as the guest material 142 will be described. Note that the guest material 142 may also be referred to as a phosphorescent material.

[0198] In Figure 1B In the case (co-host type) where the light-emitting layer contains two host materials, i.e., the organic compound 141_1 and the organic compound 141_2, an electron-transporting material and a hole-transporting material are generally used as the two host materials. By using such a structure, the hole injection barrier between the hole-transporting layer 112 and the light-emitting layer 140 and the electron injection barrier between the electron-transporting layer 118 and the light-emitting layer 140 can be reduced, and thus the driving voltage can be reduced, which is preferable.

[0199] <Luminescence mechanism of the light-emitting element> Next, the luminescence mechanism of the light-emitting layer 140 will be described below.

[0200] The organic compound 141_1 and the organic compound 141_2 included in the host material 141 in the light-emitting layer 140 can form an exciplex. Hereinafter, the case where the organic compound 141_1 and the organic compound 141_2 form an exciplex will be described.

[0201] Figure 1C Fig. shows the energy level correlation of the organic compound 141_1, the organic compound 141_2, and the guest material 142 in the light-emitting layer 140. In addition, the terms and reference numerals in Figure 1C are shown below. Hereinafter, the description will be made on the assumption that the organic compound 141_1 is an electron-transporting material and the organic compound 141_2 is a hole-transporting material. ·Host(141_1): The organic compound 141_1 (host material) ·Host(141_2): The organic compound 141_2 (host material) ·Guest(142): The guest material 142 (phosphorescent compound) ·S PH1 : The S1 energy level of the organic compound 141_1 (host material) ·T PH1 : The T1 energy level of the organic compound 141_1 (host material) ·S PH2: S1 energy level of organic compound 141_2 (host material) ·T PH2 : T1 energy level of organic compound 141_2 (host material) ·S PG : S1 energy level of guest material 142 (phosphorescent compound) ·T PG : T1 energy level of guest material 142 (phosphorescent compound) ·S PE : S1 energy level of exciplex ·T PE : T1 energy level of exciplex

[0202] An exciplex is formed between organic compound 141_1 and organic compound 141_2, and the S1 energy level (S PE ) and T1 energy level (T PE ) of this exciplex become adjacent energy levels (refer to path E1 in Figure 1C ).

[0203] By organic compound 141_1 receiving electrons and organic compound 141_2 receiving holes, an exciplex is rapidly formed. Or, when one of them becomes an excited state, an exciplex is rapidly formed by interacting with the other. Thus, most of the excitons in the light-emitting layer 140 exist as exciplexes. The excitation energy level (S PE or T PE ) of the exciplex is lower than the S1 energy levels (S PH1 and S PH2 ) of the host materials (organic compound 141_1 and organic compound 141_2) forming the exciplex, so the excited state of the host material 141 can be formed with a lower excitation energy. Thus, the driving voltage of the light-emitting element can be reduced. Note that an exciplex can be formed by organic compound 141_1 receiving holes and organic compound 141_2 receiving electrons.

[0204] Then, by transferring the energies of both the exciplex (S PE ) and (T PE ) to the T1 energy level of the guest material 142 (phosphorescent compound), light emission is obtained (refer to paths E2 and E3 in Figure 1C ).

[0205] The T1 energy level (T PE ) of the exciplex is preferably higher than the T1 energy level (T PG ) of the guest material 142. Thus, the singlet excitation energy and triplet excitation energy of the generated exciplex can be transferred from the S1 energy level (S PE ) and T1 energy level (TPE ) Transfer to the T1 energy level (T PG ) of the guest material 142.

[0206] In order to efficiently transfer the excitation energy from the exciplex to the guest material 142, the T1 energy level (T PE ) of the exciplex is preferably equal to or lower than the T1 energy levels (T PH1 and T PH2 ) of the organic compounds (organic compound 141_1 and organic compound 141_2) that form the exciplex. Thus, quenching of the triplet excitation energy of the exciplex caused by the organic compounds (organic compound 141_1 and organic compound 141_2) is not likely to occur, and energy transfer from the exciplex to the guest material 142 occurs efficiently.

[0207] When the combination of the organic compound 141_1 and the organic compound 141_2 is a combination of a hole-transporting compound and an electron-transporting compound, the carrier balance can be easily controlled by adjusting their mixing ratio. Specifically, the weight ratio of the hole-transporting compound to the electron-transporting compound is preferably in the range of 1:9 to 9:1. In addition, by adopting this structure, the carrier balance is easily controlled, and thus the carrier recombination region is also easily controlled.

[0208] In this specification, etc., the processes of the above paths E2 and E3 are sometimes referred to as ExTET (Exciplex-Triplet Energy Transfer). In other words, in the light-emitting layer 140, supply of excitation energy from the exciplex to the guest material 142 occurs. In this case, it is not necessarily required to have high efficiency of reverse intersystem crossing from T PE to S PE and high luminescence quantum yield of S PE , so more materials can be selected. By utilizing ExTET, a light-emitting element with high luminous efficiency, low driving voltage, and high reliability can be obtained.

[0209] The combination of the organic compound 141_1 and the organic compound 141_2 only needs to be a combination that can form an exciplex. Preferably, the HOMO energy level of one of them is lower than the HOMO energy level of the other, and the LUMO energy level of one of them is lower than the LUMO energy level of the other.

[0210] <Material> Next, the details of the components of the light-emitting element according to one embodiment of the present invention will be described.

[0211] 《Light-emitting layer》 In the light-emitting layer 140, the weight ratio of the host material 141 is the highest, and the guest material 142 is dispersed in the host material 141. When the guest material 142 is a phosphorescent compound, the T1 energy level of the host material 141 (organic compounds 141_1 and 141_2) of the light-emitting layer 140 is preferably higher than the T1 energy level of the guest material (guest material 142) of the light-emitting layer 140.

[0212] The organic compound 141_1 is preferably a compound having a nitrogen-containing six-membered heteroaromatic ring skeleton. As other specific examples, compounds having a pyridine skeleton, a diazine skeleton (pyrazine skeleton, pyrimidine skeleton, and pyridazine skeleton), and a triazine skeleton can be cited. As the compound containing the basic nitrogen-containing heteroaromatic ring skeleton, for example, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, purine compounds, and the like can be cited. In addition, as the organic compound 141_1, a material with higher electron transport property than hole transport property (electron transport material) can be used, and a material having an electron mobility of 1×10 -6 cm 2 / Vs or more is preferably used.

[0213] Specifically, for example, the following can be used: heteroaromatic compounds with a pyridine skeleton such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), etc.; 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(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), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), (2-[3-(3,9'-bi-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline) (abbreviation: 2mCzCzPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothiophenyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), etc., heteroaromatic compounds with a diazine skeleton; 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), etc., heteroaromatic compounds with a triazine skeleton; 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), etc., heteroaromatic compounds with a pyridine skeleton. Among the above heteroaromatic compounds, heteroaromatic compounds with a triazine skeleton, a diazine (pyrimidine, pyrazine, pyridazine) skeleton or a pyridine skeleton are stable and highly reliable, so they are preferred. The heteroaromatic compounds with this skeleton have high electron transport properties and also contribute to the reduction of the driving voltage.In addition, high molecular 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. The substances described herein mainly have 1×10. -6 cm 2 Substances with an electron mobility of / Vs or higher. Note that as long as the electron transport property is higher than the hole transport property, substances other than the above substances can be used.

[0214] As the organic compound 141_2, a compound having a nitrogen-containing five-membered heteroaromatic ring skeleton or a tertiary amine skeleton is preferably used. Specifically, compounds having a pyrrole skeleton or an aromatic amine skeleton can be cited. For example, indole derivatives, carbazole derivatives, triarylamine derivatives, etc. can be cited. In addition, as the nitrogen-containing five-membered heteroaromatic ring skeleton, an imidazole skeleton, a triazole skeleton, and a tetrazole skeleton can be cited. In addition, as the organic compound 141_2, a material with a higher hole transport property than the electron transport property (hole transport material) can be used, and a material with a hole mobility of 1×10 -6 cm 2 / Vs or higher is preferably used. The above hole transport materials can also be high molecular compounds.

[0215] As materials with high hole transport properties, specifically, as aromatic amine compounds, N,N'-bis(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be cited.

[0216] In addition, as carbazole derivatives, specifically, 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), etc. can be cited.

[0217] In addition, as carbazole derivatives, 4,4'-bis(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can also be cited.

[0218] In addition, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-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-diphenyl-N-(9,10-diphenyl-2-anthryl)-9H-carbazol-3-amine (abbreviation: 2PCAPA), 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), N,N,N',N',N",N",N"',N"'-octaphenyldibenzo[g,p] (chrysene)-2,7,10,15-tetraamine (abbreviation: DBC1), etc. can be used.

[0219] In addition, high molecular compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N’-[4-(4-diphenylamino)phenyl]phenyl-N’-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N’-bis(4-butylphenyl)-N,N’-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc. can also be used.

[0220] In addition, as materials with high hole-transporting properties, for example, 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',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 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-(spiro-9,9'-bifluorene-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)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), 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), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-bis(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), 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), 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-amine (abbreviation: PCBBiF), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: DPA2SF), 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 other aromatic amine compounds. In addition, 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,6-bis(9H-carbazol-9-yl)-9-phenyl-9H-carbazole (abbreviation: PhCzGI), 2,8-bis(9H-carbazol-9-yl)dibenzothiophene (abbreviation: Cz2DBT) and other amine compounds and carbazole compounds can also be used. Among the above compounds, compounds having a pyrrole skeleton and an aromatic amine skeleton are stable and have good reliability, so they are preferred. In addition, compounds having the above skeletons have high hole transport properties and also contribute to the reduction of the driving voltage.,

[0221] In addition, as the organic compound 141_2, compounds having a nitrogen-containing five-membered heteroaromatic ring skeleton such as an imidazole skeleton, a triazole skeleton and a tetrazole skeleton can be used. Specifically, for example, 3-(4-biphenyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 9-[4-(4,5-diphenyl-4H-1,2,4-triazol-3-yl)phenyl]-9H-carbazole (abbreviation: CzTAZ1), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) and the like can be used.

[0222] In the light-emitting layer 140, an organometallic complex according to one embodiment of the present invention can be suitably used as the guest material 142. Since the organometallic complex according to one embodiment of the present invention has a high quantum yield, a light-emitting device with good luminous efficiency can be obtained. Further, when the light-emitting device includes a plurality of light-emitting units as in the following-described light-emitting device 250, it is preferable to use an organic compound according to one embodiment of the present invention for the light-emitting layer of one light-emitting unit. Although there is no particular limitation on the guest material for other light-emitting units, anthracene derivatives, tetracene derivatives, (chrysene) derivatives, phenanthrene derivatives, pyrene derivatives, perylene derivatives, stilbene derivatives, acridone derivatives, coumarin derivatives, phenoxazine derivatives, phenothiazine derivatives, etc. can be preferably used, and for example, the following substances can be used.

[0223] Specifically, as such materials, 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N'-bis(4-tert-butylphenyl)pyrene-1,6-diamine (abbreviation: 1,6tBu-FLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-3,8-dicyclohexylpyrene-1,6-diamine (abbreviation: ch-1,6FLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenyldistyrene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyl-di-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-benzenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-benzenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p] (chrysene)-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 6, Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), Rubrene, 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (abbreviation: TBRb), Nile Red, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)vinyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,{5H-benzo[ij]quinolin-9-yl)vinyl]-4H-pyran-4-ylidene}malononitrile (abbreviation: BisDCJTM), 5,10,15,20-tetraphenylbisbenzo[5,6]indeno[1,2,3-cd:1',2',3'-lm]perylene, etc.

[0224] As phosphorescent compounds that can be used as host materials, iridium, rhodium, platinum-based organometallic complexes or metal complexes can be mentioned. Among them, organoiridium complexes are preferred, such as iridium orthometallic complexes. As orthometalated ligands, 4H-triazole ligands, 1H-triazole ligands, imidazole ligands, pyridine ligands, pyrimidine ligands, pyrazine ligands or isoquinoline ligands, etc. can be mentioned. As metal complexes, platinum complexes having porphyrin ligands, etc. can be mentioned.

[0225] As substances having a luminescence peak in the blue or green wavelength region, for example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviation: [Ir(iPr5btz)3]) and other organometallic iridium complexes having a 4H-triazole skeleton; tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]) and other organometallic iridium complexes having a 1H-triazole skeleton; fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]) and other organometallic iridium complexes having an imidazole skeleton; and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2'Iridium(III) tetra(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2'}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' iridium(III) acetylacetonate (abbreviation: [FIr(acac)]), etc., which are organometallic iridium complexes with phenylpyridine compounds having an electron-withdrawing group as ligands. Among the above metal complexes, organometallic iridium complexes having a nitrogen-containing five-membered heteroaromatic ring skeleton such as a 4H-triazole skeleton, a 1H-triazole skeleton, and an imidazole skeleton have a very high triplet excitation energy and excellent reliability and luminescence efficiency, and are therefore particularly preferred.

[0226] As substances having a luminescence peak in the green or yellow wavelength region, for example, tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidine)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidine)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[4-(2-norbornanyl)-6-phenylpyrimidine]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidine]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidine)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), etc., which are organometallic iridium complexes having a pyrimidine skeleton; (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), etc., which are organometallic iridium complexes having a pyrazine skeleton; tris(2-phenylpyridine-N,C 2') Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2' ) iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2′ ) iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2' ) iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]) and other organometallic iridium complexes with a pyridine skeleton; bis(2,4-diphenyl-1,3-oxazolato-N,C 2' ) iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinato-N,C 2'} iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolato-N,C 2' ) iridium(III) acetylacetonate (abbreviation: [Ir(bt)2(acac)]) and other organometallic iridium complexes; tris(acetylacetonato)(monophenanthroline) terbium(III) (abbreviation: [Tb(acac)3(Phen)]) and other rare earth metal complexes. Among the above substances, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they also have significantly excellent reliability and luminescence efficiency.

[0227] In addition, as substances having a luminescence peak in the yellow or red wavelength region, for example, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](di-neopentanoylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-bis(naphthalen-1-yl)pyrimidinato](di-neopentanoylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]) and other organometallic iridium complexes having a pyrimidine skeleton can be cited; (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(di-neopentanoylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]) and other organometallic iridium complexes having a pyrazine skeleton; tris(1-phenylisoquinoline-N,C 2’ )iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinoline-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]) and other organometallic iridium complexes having a pyridine skeleton; platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: [PtOEP]); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-thienoyl)-3,3,3-trifluoroacetone](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]). Among the above substances, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they also have significantly high reliability and luminescence efficiency. In addition, organometallic iridium complexes having a pyrazine skeleton can achieve red light with good chromaticity.

[0228] Since organic compounds having a benzofuranopyridine skeleton or a benzothiophenopyridine skeleton have a high T1 energy level, they are suitable as the host material for a light-emitting layer using a substance capable of converting triplet excitation energy into light emission as a light-emitting material. Therefore, as the light-emitting material included in the light-emitting layer 140, a material capable of converting triplet excitation energy into light emission is preferably used. As the material capable of converting triplet excitation energy into light emission, in addition to the above-mentioned phosphorescent compounds, thermally activated delayed fluorescence (TADF) materials can be cited. Therefore, the description regarding phosphorescent compounds can be regarded as the description regarding thermally activated delayed fluorescence materials. Note that a thermally activated delayed fluorescence material is a material in which the difference between the triplet excitation energy level and the singlet excitation energy level is small and has a function of converting energy from the triplet excited state into the singlet excited state through reverse intersystem crossing. Therefore, the triplet excited state can be up-converted into the singlet excited state (reverse intersystem crossing) by a small amount of thermal energy, and light emission (fluorescence) from the singlet excited state can be efficiently presented. In addition, the conditions for efficiently obtaining thermally activated delayed fluorescence are as follows: the energy difference between the triplet excited state energy level and the singlet excited state energy level is greater than 0 eV and 0.2 eV or less, preferably greater than 0 eV and 0.1 eV or less.

[0229] When the thermally activated delayed fluorescence material is composed of one material, for example, the following materials can be used.

[0230] First, fullerenes or their derivatives, acridine derivatives such as proflavine, eosin, etc. can be cited. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. can be cited. As the metal-containing porphyrin, for example, protoporphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(CoproⅢ-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2OEP), etc. can also be cited.

[0231] In addition, as a thermally activated delayed fluorescence material composed of one kind of material, a heteroaromatic compound having a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used. Specifically, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro[acridine-9,9’-anthracene]-10’-one (abbreviation: ACRSA), etc. can be cited. Since the heteroaromatic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, it has high electron transportability and hole transportability, and thus is preferred. In particular, in the skeleton having a π-electron-deficient heteroaromatic ring, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or a triazine skeleton is stable and has good reliability, and thus is preferred. In addition, in the skeleton having a π-electron-rich heteroaromatic ring, an acridine skeleton, a phenoxazine skeleton, a thiophene skeleton, a furan skeleton, and a pyrrole skeleton are stable and have good reliability, and thus it is preferred to have any one or more of these skeletons. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferably used. In addition, in a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, both the donor property of the π-electron-rich heteroaromatic ring and the acceptor property of the π-electron-deficient heteroaromatic ring are strong, and the energy level difference between the singlet excited state and the triplet excited state is small, and thus it is particularly preferred.

[0232] In addition, the light-emitting layer 140 may also include materials other than the host material 141 and the guest material 142.

[0233] There is no particular limitation on the material that can be used for the light-emitting layer 140. For example, anthracene derivatives, phenanthrene derivatives, pyrene derivatives, derivatives, dibenzo[g,p] derivatives, etc. of condensed polycyclic aromatic compounds can be cited. Specifically, 9,10-diphenylanthracene (abbreviation: DPAnth), 6,12-dimethoxy-5,11-diphenyl 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'-bianthracene (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tris(1-pyrenyl)benzene (abbreviation: TPB3), etc. Additionally, one or more substances having a singlet excitation energy level or a triplet excitation energy level higher than that of the above-mentioned host material 142 can be selected from the above substances and well-known substances for use.

[0234] Additionally, for example, compounds having a heteroaromatic ring skeleton such as oxadiazole derivatives can be used for the light-emitting layer 140. Specifically, for example, 2-(4-biphenyl)-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), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs) and other heteroaromatic compounds can be cited.

[0235] Additionally, metal complexes having a heteroaromatic ring (for example, zinc and aluminum-based metal complexes, etc.) can be used for the light-emitting layer 140. For example, metal complexes including quinoline ligands, benzoquinoline ligands, oxazole ligands or thiazole ligands can be cited. Specifically, metal complexes having a quinoline skeleton or a benzoquinoline skeleton, etc., such as tris(8-hydroxyquinoline)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviation: BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviation: Znq), etc. Additionally, in addition to this, metal complexes having oxazole-based or thiazole-based ligands such as bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviation: ZnBTZ), etc. can also be used.

[0236] The light-emitting layer 140 may also be formed of two or more layers. For example, in the case where the first light-emitting layer and the second light-emitting layer are sequentially stacked from the hole-transporting layer side to form the light-emitting layer 140, a substance having hole-transporting properties may be used as the host material of the first light-emitting layer, and a substance having electron-transporting properties may be used as the host material of the second light-emitting layer. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be the same or different materials. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be materials having the function of emitting light of the same color or materials having the function of emitting light of different colors. By using light-emitting materials having the function of emitting light of different colors from each other for the two light-emitting layers, multiple emissions can be obtained simultaneously. In particular, it is preferable to select the light-emitting materials for each light-emitting layer so that white light emission can be obtained by combining the light emitted from the two light-emitting layers.

[0237] In addition, the light-emitting layer 140 may be formed by a method such as a vapor deposition method (including a vacuum vapor deposition method), an inkjet method, a coating method, or a gravure printing method. In addition, in addition to the above materials, the light-emitting layer 140 may also contain an inorganic compound such as a quantum dot or a polymer compound (oligomer, dendrimer, polymer, etc.).

[0238] 《Hole Injection Layer》 The hole injection layer 111 has the function of promoting hole injection by reducing the hole injection barrier from one of the pair of electrodes (electrode 101 or electrode 102), and is formed, for example, using a transition metal oxide, a phthalocyanine derivative, or an aromatic amine. Examples of the transition metal oxide include molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide. Examples of the phthalocyanine derivative include phthalocyanine or metal phthalocyanine. Examples of the aromatic amine include a benzidine derivative or a phenylenediamine derivative. In addition, a polymer compound such as polythiophene or polyaniline may also be used. Typically, poly(ethylenedioxythiophene) / poly(styrenesulfonic acid) or the like, which is a self-doped polythiophene, is used.

[0239] The hole injection layer 111 may also include a composite material of a hole transporting material and a material that exhibits electron accepting properties with respect to the hole transporting material. Alternatively, a laminate of a layer containing a material that exhibits electron accepting properties and a layer containing a hole transporting material may be used. In a steady state or in the presence of an electric field, charge transfer can occur between these materials. Examples of the material that exhibits electron accepting properties include organic acceptors such as quinodimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatriphenylene derivatives. Specifically, compounds having an electron withdrawing group (halogen group or cyano group) such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, and 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN) can be cited. In addition, transition metal oxides, for example, oxides of metals belonging to Groups 4 to 8, may be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, etc. can be used. Molybdenum oxide is particularly preferably used because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle.

[0240] As the hole transporting material, a material having a higher hole transporting property than an electron transporting property can be used, and a material having a hole mobility of 1×10 -6 cm 2 / Vs or more is preferably used. Specifically, aromatic amines, carbazole derivatives, aromatic hydrocarbons, stilbene derivatives, etc., which are cited as hole transporting materials that can be used for the light emitting layer 140, can be used. The above hole transporting material may also be a polymer compound.

[0241] In addition, aromatic hydrocarbons can also be cited as hole-transporting materials. For example, 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-bis(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-bis(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-bis(2-naphthyl)anthracene, 9,9'-bianthracene, 10,10'-diphenyl-9,9'-bianthracene, 10,10'-bis(2-phenylphenyl)-9,9'-bianthracene, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthracene, anthracene, tetracene, rubrene, chrysene, 2,5,8,11-tetra(tert-butyl)chrysene, etc. can be cited. In addition, pentacene, coronene, etc. can also be used. Thus, it is more preferable to use an aromatic hydrocarbon having a hole mobility of 1×10 -6 cm 2 / Vs or more and having 14 to 42 carbon atoms.

[0242] In addition, the aromatic hydrocarbon can have a vinyl skeleton. As the aromatic hydrocarbon having a vinyl group, for example, 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), etc. can be cited.

[0243] In addition, thiophene compounds, furan compounds, fluorene compounds, triphenylene compounds, phenanthrene compounds, etc., such as 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tris(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II), etc. Among them, compounds having a pyrrole skeleton, a furan skeleton, a thiophene skeleton, and an aromatic amine skeleton are stable and have good reliability, so they are preferred. Compounds having the above skeletons have high hole transport properties and also contribute to a reduction in driving voltage.

[0244] 《Hole Transport Layer》 The hole transport layer 112 is a layer containing a hole transport material, and the hole transport materials exemplified as the materials for the hole injection layer 111 can be used. The hole transport layer 112 has the function of transporting the holes injected into the hole injection layer 111 to the light-emitting layer 140, so it preferably has a HOMO energy level that is the same as or adjacent to the HOMO energy level of the hole injection layer 111.

[0245] In addition, it is preferable to use a substance having a hole mobility of 1×10 -6 cm 2 / Vs or more. However, as long as the substance has higher hole transport properties than electron transport properties, substances other than the above substances can be used. In addition, the layer including a substance having high hole transport properties is not limited to a single layer, and two or more layers composed of the above substances can also be stacked.

[0246] 《Electron Transport Layer》 The electron transport layer 118 has the function of transporting the electrons injected through the electron injection layer 119 from the other of the pair of electrodes (electrode 101 or electrode 102) to the light-emitting layer 140. As the electron transport material, a material having higher electron transport properties than hole transport properties can be used, and it is preferable to use a material having a hole mobility of 1×10 -6 cm 2Materials with an electron mobility of 1×10 -6 cm 2 / Vs or higher. As a compound that easily accepts electrons (a material with electron-transporting properties), a π-deficient heteroaromatic compound such as a nitrogen-containing heteroaromatic compound or a metal complex can be used. As other specific examples, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, triazine derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, phenanthroline derivatives, triazole derivatives, benzimidazole derivatives, oxadiazole derivatives, etc., which are cited as electron-transporting materials that can be used in the light-emitting layer 140, can be mentioned. Additionally, it is preferably a substance with an electron mobility of 1×10

[0247] cm

[0248] / Vs or higher. Additionally, as long as the material has higher electron-transporting properties than hole-transporting properties, substances other than the above-mentioned substances can be used as the electron-transporting layer. Additionally, the electron-transporting layer 118 is not limited to a single layer and can also be a laminate of two or more layers composed of the above-mentioned substances.

[0249] 《Electron Injection Layer》 The electron injection layer 119 has the function of promoting electron injection by reducing the electron injection barrier at the interface with the electrode 102. For example, Group 1 metals, Group 2 metals, or their oxides, halides, carbonates, etc. can be used. Additionally, a composite material of the above-mentioned electron transporting material and a material that exhibits electron-donating properties to the electron transporting material can also be used. As materials that exhibit electron-donating properties, Group 1 metals, Group 2 metals, or their oxides, etc. can be cited. Specifically, lithium fluoride (LiF), sodium fluoride (NaF), cesium fluoride (CsF), calcium fluoride (CaF2), and lithium oxide (LiO x ) and other alkali metals, alkaline earth metals, or compounds of these metals can be used. Additionally, rare earth metal compounds such as erbium fluoride (ErF3) can be used. Additionally, an electron salt can be used for the electron injection layer 119. As such an electron salt, for example, a substance that adds electrons to a mixed oxide of calcium and aluminum at a high concentration, etc. can be cited. Additionally, a substance that can be used for the electron transport layer 118 can also be used for the electron injection layer 119.

[0250] Additionally, a composite material formed by mixing an organic compound with an electron donor can be used for the electron injection layer 119. Such a composite material has excellent electron injection properties and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in the performance of transporting the generated electrons. Specifically, for example, the substances (metal complexes, heteroaromatic compounds, etc.) that constitute the electron transport layer 118 as described above can be used. As the electron donor, any substance that exhibits electron-donating properties to the organic compound can be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferably used, and lithium, sodium, cesium, magnesium, calcium, erbium, ytterbium, etc. can be cited. Additionally, alkali metal oxides or alkaline earth metal oxides are preferably used, and lithium oxide, calcium oxide, barium oxide, etc. can be cited. In addition, Lewis bases such as magnesium oxide can also be used. Additionally, organic compounds such as tetrathiafulvalene (abbreviation: TTF) can also be used.

[0251] Additionally, the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer can be formed by methods such as evaporation (including vacuum evaporation), inkjet, coating, gravure printing, etc. Additionally, as the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron transport layer, and electron injection layer, in addition to the above materials, inorganic compounds such as quantum dots or polymer compounds (oligomers, dendrimers, polymers, etc.) can also be used.

[0252] 《Quantum Dots》 Quantum dots are semiconductor nanocrystals with a size of several nm to several tens of nm, and are composed of 1×10 3 to 1×10 6It is composed of about several tens of atoms. The energy shift of the quantum dot depends on its size. Therefore, even quantum dots composed of the same substance have different emission wavelengths according to their sizes. So, by changing the size of the quantum dots used, it is easy to change the emission wavelength.

[0253] In addition, the peak width of the emission spectrum of the quantum dot is narrow. Therefore, highly color-pure light emission can be obtained. Furthermore, the theoretical internal quantum efficiency of the quantum dot is considered to be approximately 100%, that is, it greatly exceeds 25% of the organic compound that exhibits fluorescence emission and is equal to the organic compound that exhibits phosphorescence emission. Therefore, by using the quantum dot as a light-emitting material, a light-emitting element with high luminous efficiency can be obtained. Moreover, the quantum dot, which is an inorganic material, is also excellent in substantial stability. Therefore, a light-emitting element with a long service life can be obtained.

[0254] Examples of the material constituting the quantum dot include Group 14 elements, Group 15 elements, Group 16 elements, compounds containing multiple Group 14 elements, compounds of elements from Group 4 to Group 14 and Group 16 elements, compounds of Group 2 elements and Group 16 elements, compounds of Group 13 elements and Group 15 elements, compounds of Group 13 elements and Group 17 elements, compounds of Group 14 elements and Group 15 elements, compounds of Group 11 elements and Group 17 elements, iron oxide-based materials, titanium oxide-based materials, spinel chalcogenide-based materials, semiconductor clusters, etc.

[0255] Specifically, cadmium selenide, cadmium sulfide, cadmium telluride, zinc selenide, zinc oxide, zinc sulfide, zinc telluride, mercury sulfide, mercury selenide, mercury telluride, indium arsenide, indium phosphide, gallium arsenide, gallium phosphide, indium nitride, gallium nitride, indium antimonide, gallium antimonide, aluminum phosphide, aluminum arsenide, aluminum antimonide, lead selenide, lead telluride, lead sulfide, indium selenide, indium telluride, indium sulfide, gallium selenide, arsenic sulfide, arsenic selenide, arsenic telluride, antimony sulfide, antimony selenide, antimony telluride, bismuth sulfide, bismuth selenide, bismuth telluride, silicon, silicon carbide, germanium, tin, selenium, tellurium, boron, carbon, phosphorus, boron nitride, boron phosphide, arsenic boron, aluminum nitride, aluminum sulfide, barium sulfide, barium selenide, barium telluride, calcium sulfide, calcium selenide, calcium telluride, beryllium sulfide, beryllium selenide, beryllium telluride, magnesium sulfide, magnesium selenide, germanium sulfide, germanium selenide, germanium telluride, tin sulfide, tin sulfide, tin selenide, tin telluride, lead oxide, copper fluoride, copper chloride, copper bromide, copper iodide, copper oxide, copper selenide, nickel oxide, cobalt oxide, cobalt sulfide, iron oxide, iron sulfide, manganese oxide, molybdenum sulfide, vanadium oxide, tungsten oxide, tantalum oxide, titanium oxide, zirconium oxide, silicon nitride, germanium nitride, aluminum oxide, barium titanate, compounds of selenium zinc cadmium, compounds of indium arsenic phosphorus, compounds of cadmium selenium sulfur, compounds of cadmium selenium tellurium, compounds of indium gallium arsenic, compounds of indium gallium selenium, indium selenium sulfur compounds, copper indium sulfur compounds, and their combinations, etc., but not limited thereto. In addition, so-called alloy-type quantum dots represented by any ratio of composition can also be used. For example, since the alloy-type quantum dots of cadmium selenium sulfur can change the emission wavelength by changing the content ratio of elements, the alloy-type quantum dots of cadmium selenium sulfur are one of the effective methods for obtaining blue light.

[0256] As the structure of the quantum dots, there are core type, core shell type, core multishell type, etc. Any of the above can be used, but by forming a shell using other inorganic materials that cover the core and have a wider bandgap, the influence of defects or dangling bonds present on the surface of the nanocrystals can be reduced, and thus the quantum efficiency of luminescence can be greatly improved. Therefore, it is preferable to use core shell type or core multishell type quantum dots. As an example of the material for the shell, zinc sulfide or zinc oxide can be cited.

[0257] In addition, in quantum dots, due to the high proportion of surface atoms, the reactivity is high and aggregation is likely to occur. Therefore, it is preferable that a protective agent is attached to the surface of the quantum dots or a protecting group is provided. Thereby, aggregation can be prevented and the solubility in a solvent can be improved. In addition, the electrical stability can be improved by reducing the reactivity. Examples of the protective agent (or protecting group) include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; trialkylphosphines such as tripropylphosphine, tributylphosphine, trihexylphosphine, and trioctylphosphine; polyoxyethylene alkylphenyl ethers such as polyoxyethylene n-octylphenyl ether and polyoxyethylene n-nonylphenyl ether; tertiary amines such as tris(n-hexyl)amine, tris(n-octyl)amine, and tris(n-decyl)amine; organophosphorus compounds such as tripropylphosphine oxide, tributylphosphine oxide, trihexylphosphine oxide, trioctylphosphine oxide, and tridecylphosphine oxide; polyethylene glycol diesters such as polyethylene glycol dilaurate and polyethylene glycol distearate; organic nitrogen compounds such as nitrogen-containing aromatic compounds such as pyridine, lutidine, collidine, and quinoline; aminoalkanes such as hexylamine, octylamine, decylamine, dodecylamine, tetradecylamine, hexadecylamine, and octadecylamine; dialkyl sulfides such as dibutyl sulfide; dialkyl sulfoxides such as dimethyl sulfoxide and dibutyl sulfoxide; organic sulfur compounds such as sulfur-containing aromatic compounds such as thiophene; higher fatty acids such as palmitic acid, stearic acid, and oleic acid; alcohols; sorbitan fatty acid esters; fatty acid-modified polyesters; tertiary amine-modified polyurethanes; polyethyleneimines, etc.

[0258] The smaller the size of the quantum dots, the larger the band gap, so the size is appropriately adjusted to obtain light of a desired wavelength. As the crystal size becomes smaller, the luminescence of the quantum dots shifts to the blue side (i.e., to the high energy side). Therefore, by changing the size of the quantum dots, the emission wavelength can be adjusted in the wavelength region covering the ultraviolet region, visible light region, and infrared region of the spectrum. The size (diameter) of the quantum dots commonly used is 0.5 nm to 20 nm, preferably 1 nm to 10 nm. In addition, the smaller the size distribution of the quantum dots, the narrower the emission spectrum, so that luminescence with high color purity can be obtained. In addition, there is no particular limitation on the shape of the quantum dots, which can be spherical, rod-shaped, disk-shaped, or other shapes. In addition, the quantum rod, which is a rod-shaped quantum dot, has the function of presenting directional light. Therefore, by using the quantum rod as a luminescent material, a light-emitting element with a higher external quantum efficiency can be obtained.

[0259] In an organic EL element, concentration quenching of a light-emitting material is usually suppressed by dispersing the light-emitting material in a host material, thereby improving the light-emitting efficiency. The host material needs to have a singlet excitation level or a triplet excitation level higher than that of the light-emitting material. In particular, when a blue phosphorescent material is used as the light-emitting material, a host material having a triplet excitation level higher than that of the blue phosphorescent material and a long lifetime is required, and the development of such a material is extremely difficult. Here, even when a light-emitting layer is formed using only quantum dots without using a host material, the light-emitting efficiency can be ensured, and thus a light-emitting element with a long lifetime can be obtained. When a light-emitting layer is formed using only quantum dots, the quantum dots preferably have a core-shell structure (including a core-multiple shell structure).

[0260] When a quantum dot is used as the light-emitting material of the light-emitting layer, the thickness of the light-emitting layer is 3 nm to 100 nm, preferably 10 nm to 100 nm, and the ratio of the quantum dots contained in the light-emitting layer is 1 vol.% to 100 vol.%. Note that it is preferable to form the light-emitting layer only of quantum dots. In addition, when forming a light-emitting layer in which the quantum dot is used as the light-emitting material and dispersed in the host material, the quantum dots can be dispersed in the host material or the host material and the quantum dots can be dissolved or dispersed in an appropriate liquid medium, and a wet method (spin coating method, casting method, dispensing coating method, blade coating method, roll coating method, inkjet method, printing method, spraying method, curtain coating method, Langmuir Blodgett method, etc.) can be used for formation. For a light-emitting layer using a phosphorescent light-emitting material, a vacuum evaporation method can also be adopted in addition to the above wet methods.

[0261] As the liquid medium for the wet method, for example, the following can be used: ketones such as methyl ethyl ketone and cyclohexanone; fatty acid esters such as ethyl acetate; halogenated hydrocarbons such as dichlorobenzene; aromatic hydrocarbons such as toluene, xylene, mesitylene, and cyclohexylbenzene; aliphatic hydrocarbons such as cyclohexane, decalin, and dodecane; and organic solvents such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0262] 《A pair of electrodes》 Electrodes 101 and 102 are used as the anode or cathode of the light-emitting element. Electrodes 101 and 102 can be formed using metals, alloys, conductive compounds, and mixtures or laminates thereof, etc.

[0263] One of the electrode 101 and the electrode 102 is preferably formed of a conductive material having a function of reflecting light. As such a conductive material, aluminum (Al) or an alloy containing Al can be cited. As an alloy containing Al, an alloy containing Al and L (L represents one or more of titanium (Ti), neodymium (Nd), nickel (Ni), and lanthanum (La)) can be cited, for example, an alloy containing Al and Ti or an alloy containing Al, Ni, and La. Aluminum has a low resistivity and a high light reflectivity. In addition, since aluminum is abundantly contained in the earth's crust and is not expensive, using aluminum can reduce the manufacturing cost of the light-emitting element. In addition, silver (Ag), an alloy containing Ag and N (N represents one or more of yttrium (Y), Nd, magnesium (Mg), ytterbium (Yb), Al, Ti, gallium (Ga), zinc (Zn), indium (In), tungsten (W), manganese (Mn), tin (Sn), iron (Fe), Ni, copper (Cu), palladium (Pd), iridium (Ir), and gold (Au)) can also be used. As an alloy containing silver, for example, the following alloys can be cited: an alloy containing silver, palladium, and copper; an alloy containing silver and copper; an alloy containing silver and magnesium; an alloy containing silver and nickel; an alloy containing silver and gold; and an alloy containing silver and ytterbium. In addition to the above materials, transition metals such as tungsten, chromium (Cr), molybdenum (Mo), copper, and titanium can be used.

[0264] In addition, the light obtained from the light-emitting layer is extracted by passing through one or both of the electrode 101 and the electrode 102. Therefore, at least one of the electrode 101 and the electrode 102 is preferably formed of a conductive material having a function of transmitting light. As such a conductive material, a conductive material having a visible light transmittance of 40% or more and 100% or less, preferably 60% or more and 100% or less, and a resistivity of 1×10 -2 Ω·cm or less can be cited.

[0265] In addition, the electrode 101 and the electrode 102 can also be formed of a conductive material having a function of transmitting light and a function of reflecting light. As such a conductive material, a conductive material having a visible light reflectivity of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a resistivity of 1×10 -2A conductive material with a resistivity of less than

[0266] Note that in this specification, etc., as a material having a light-transmitting function, a material having a function of transmitting visible light and having conductivity may be used. For example, there are oxide conductors, oxide semiconductors, or organic conductors containing organic substances represented by ITO as described above. As an organic conductor containing an organic substance, for example, a composite material formed by mixing an organic compound and an electron donor (donor), a composite material formed by mixing an organic compound and an electron acceptor (acceptor), etc. may be cited. In addition, inorganic carbon materials such as graphene may also be used. In addition, the resistivity of this material is preferably 1×10 5 Ω·cm or less, more preferably 1×10 4 Ω·cm or less.

[0267] In addition, one or both of the electrode 101 and the electrode 102 may be formed by laminating a plurality of the above materials.

[0268] In order to improve the light extraction efficiency, a material having a refractive index higher than that of the electrode may be formed in contact with the electrode having a light-transmitting function. As such a material, as long as it has a function of transmitting visible light, it may be a conductive material or a non-conductive material. For example, in addition to the above oxide conductors, oxide semiconductors and organic substances may also be cited. As an organic substance, for example, materials exemplified as a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, or an electron injection layer may be cited. In addition, inorganic carbon materials or metal thin films having a thickness of a light-transmitting degree may also be used, and a plurality of layers having a thickness of several nm to several tens of nm may also be laminated.

[0269] When the electrode 101 or the electrode 102 functions as a cathode, a material with a small work function (below 3.8 eV) is preferably used. For example, elements belonging to Group 1 or Group 2 of the periodic table (such as alkali metals like lithium, sodium, and cesium, alkaline earth metals like calcium or strontium, and magnesium), alloys containing the above elements (such as Ag and Mg or Al and Li), rare earth metals such as europium (Eu) or ytterbium (Yb), alloys containing the above rare earth metals, alloys containing aluminum and silver, etc. can be used.

[0270] When the electrode 101 or the electrode 102 is used as an anode, a material with a large work function (4.0 eV or more) is preferably used.

[0271] The electrodes 101 and 102 can also be a laminate of a conductive material having a function of reflecting light and a conductive material having a function of transmitting light. In this case, the electrodes 101 and 102 have a function of adjusting the optical distance so that light of a desired wavelength from each light-emitting layer resonates to enhance the light of that wavelength, which is preferable.

[0272] As a film-forming method for the electrodes 101 and 102, a sputtering method, an evaporation method, a printing method, a coating method, an MBE (Molecular Beam Epitaxy) method, a CVD method, a pulsed laser deposition method, an ALD (Atomic Layer Deposition) method, etc. can be appropriately used.

[0273] 《Substrate》 In addition, a light-emitting element according to one embodiment of the present invention can be manufactured on a substrate made of glass, plastic, etc. As the stacking order on the substrate, it can be stacked in order from the electrode 101 side, or can be stacked in order from the electrode 102 side.

[0274] In addition, as a substrate on which a light-emitting element according to one embodiment of the present invention can be formed, for example, glass, quartz, or plastic can be used. Alternatively, a flexible substrate can also be used. A flexible substrate is a substrate that can be bent (flexible), such as a plastic substrate made of polycarbonate or polyarylate. In addition, a thin film, an inorganic evaporated thin film, etc. can be used. Note that as long as it functions as a support during the manufacturing process of the light-emitting element and the optical element, other materials can be used. Or, as long as it has a function of protecting the light-emitting element and the optical element.

[0275] For example, in this specification and the like, various substrates can be used to form light-emitting elements. There is no particular limitation on the type of substrate. As examples of such substrates, for example, semiconductor substrates (e.g., single-crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless-steel substrates, substrates having stainless-steel foils, tungsten substrates, substrates having tungsten foils, flexible substrates, laminated films, papers or base films containing fibrous materials, etc. can be used. As examples of glass substrates, there are barium borosilicate glass, aluminosilicate glass, soda-lime glass, etc. As examples of flexible substrates, laminated films, base films, etc., the following can be cited. For example, plastics represented by polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyethersulfone (PES), and polytetrafluoroethylene (PTFE) can be cited. Or, as an example, resins such as acrylic resins can be cited. Or, as an example, polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride, etc. can be cited. Or, as an example, polyamides, polyimides, aramid, epoxy resins, inorganic vapor-deposited films, papers, etc. can be cited.

[0276] In addition, a flexible substrate can also be used as a substrate and a light-emitting element can be directly formed on the flexible substrate. Or, a release layer can also be provided between the substrate and the light-emitting element. The release layer can be used when a part or all of the light-emitting element is manufactured on the release layer and then separated from the substrate and transferred to another substrate. At this time, the light-emitting element can also be transferred to a substrate with low heat resistance or a flexible substrate. In addition, as the above-mentioned release layer, for example, a laminated structure of inorganic films such as a tungsten film and a silicon oxide film or a structure in which a resin film such as polyimide is formed on the substrate can be used.

[0277] That is to say, one substrate can also be used to form a light-emitting element, and then the light-emitting element can be transferred to another substrate. As examples of the substrate to which the light-emitting element is transferred, in addition to the above-mentioned substrates, glassine substrates, stone substrates, wood substrates, cloth substrates (including natural fibers (silk, cotton, linen), synthetic fibers (nylon, polyurethane, polyester), or regenerated fibers (acetate fiber, cuprammonium fiber, rayon, regenerated polyester), etc.), leather substrates, rubber substrates, etc. can be cited. By adopting these substrates, light-emitting elements that are not easily damaged, light-emitting elements with high heat resistance, light-emitting elements that achieve weight reduction, or light-emitting elements that achieve thinning can be manufactured.

[0278] In addition, for example, a field-effect transistor (FET) can also be formed on the above-mentioned substrate, and a light-emitting element 150 can be manufactured on an electrode electrically connected to the FET. Thus, an active matrix display device that controls the driving of the light-emitting element 150 through the FET can be manufactured.

[0279] The structure shown in this embodiment can be implemented by appropriately combining with the structures shown in other embodiments.

[0280] (Embodiment 4) In this embodiment, with reference to Figure 2 a light-emitting element having a structure different from that of the light-emitting element shown in Embodiment 3 will be described. Note that in Figure 2 , for parts having the same functions as those indicated by the same reference numerals in Figure 1A the drawings, the same shading is used, and sometimes the reference numerals are omitted. In addition, parts having the same functions as Figure 1A are denoted by the same reference numerals, and sometimes their detailed descriptions are omitted.

[0281] <Example structure 2 of the light-emitting element> Figure 2 is a cross-sectional schematic view of the light-emitting element 250.

[0282] Figure 2 The light-emitting element 250 shown in Figure 1A has a plurality of light-emitting units (light-emitting unit 106 and light-emitting unit 108) between a pair of electrodes (electrode 101 and electrode 102). One of the plurality of light-emitting units preferably has the same structure as the Figure 1A EL layer 100 shown in

[0283] In Figure 2 the light-emitting element 250 shown in

[0284] the light-emitting units 106 and 108 are stacked, and a charge generation layer 115 is provided between the light-emitting unit 106 and the light-emitting unit 108. In addition, the light-emitting units 106 and 108 may have the same structure or different structures. For example, the light-emitting unit 108 preferably has the same structure as the EL layer 100.

[0285] In the light-emitting element 250, any one of the layers of the light-emitting unit 106 and the light-emitting unit 108 may contain an organometallic complex according to one aspect of the present invention. Note that as the layer containing the organic compound, the light-emitting layer 120 or the light-emitting layer 170 is preferably used.

[0286] The charge generation layer 115 can be either a structure in which an acceptor substance as an electron acceptor is added to a hole transport material or a structure in which a donor substance as an electron donor is added to an electron transport material. Additionally, these two structures can be laminated.

[0287] When the charge generation layer 115 contains a composite material composed of an organic compound and an acceptor substance, the composite material used can be the same as the composite material used for the hole injection layer 111 shown in Embodiment 3. As the organic compound, various compounds such as aromatic amine compounds, carbazole compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Additionally, as the organic compound, it is preferably a substance with a hole mobility of 1×10 -6 cm 2 / Vs or higher. However, as long as the substance has higher hole transportability than electron transportability, substances other than these can be used. Since the composite material composed of an organic compound and an acceptor substance has good carrier injection properties and carrier transport properties, low-voltage driving and low-current driving can be achieved. Note that when the surface on the anode side of the light-emitting unit is in contact with the charge generation layer 115, the charge generation layer 115 can also function as the hole injection layer or hole transport layer of the light-emitting unit, so the hole injection layer or hole transport layer may not be provided in the light-emitting unit. Alternatively, when the surface on the cathode side of the light-emitting unit is in contact with the charge generation layer 115, the charge generation layer 115 can also function as the electron injection layer or electron transport layer of the light-emitting unit, so the electron injection layer or electron transport layer may not be provided in the light-emitting unit.

[0288] Note that the charge generation layer 115 can also be a laminated structure combining a layer containing a composite material composed of an organic compound and an acceptor substance and a layer composed of other materials. For example, it can also be a structure combining a layer containing a composite material composed of an organic compound and an acceptor substance and a layer containing one compound selected from electron-donating substances and a compound with high electron transportability. Additionally, it can also be a structure combining a layer containing a composite material composed of an organic compound and an acceptor substance and a layer containing a transparent conductive film.

[0289] The charge generation layer 115 sandwiched between the light-emitting unit 106 and the light-emitting unit 108 only needs to have a structure that injects electrons into one light-emitting unit and injects holes into the other light-emitting unit when a voltage is applied between the electrode 101 and the electrode 102. For example, in Figure 2 , when a voltage is applied in such a way that the potential of the electrode 101 is higher than the potential of the electrode 102, the charge generation layer 115 injects electrons into the light-emitting unit 106 and injects holes into the light-emitting unit 108.

[0290] From the viewpoint of light extraction efficiency, the charge generation layer 115 preferably has visible light transmittance (specifically, the transmittance of visible light is 40% or more). In addition, the charge generation layer 115 functions even if its conductivity is less than that of a pair of electrodes (electrode 101 and electrode 102).

[0291] By forming the charge generation layer 115 using the above materials, an increase in the driving voltage when stacking the light-emitting layers can be suppressed.

[0292] Although a light-emitting element having two light-emitting units is described in Figure 2 the same structure can be applied to a light-emitting element in which three or more light-emitting units are stacked. As shown in the light-emitting element 250, by arranging a plurality of light-emitting units between a pair of electrodes in such a manner that they are separated by a charge generation layer, a light-emitting element that can emit high-brightness light while maintaining a low current density and has a longer lifespan can be realized. In addition, a light-emitting element with low power consumption can also be realized.

[0293] In addition, in each of the above structures, the luminescent colors of the host materials for the light-emitting unit 106 and the light-emitting unit 108 may be the same or different. When the light-emitting unit 106 and the light-emitting unit 108 contain host materials having a function of emitting light of the same color, the light-emitting element 250 becomes a light-emitting element that exhibits high light-emitting brightness at a lower current value, so it is preferable. In addition, when the light-emitting unit 106 and the light-emitting unit 108 contain host materials having a function of emitting light of different colors from each other, the light-emitting element 250 emits light of multiple colors, so it is preferable. At this time, when a plurality of light-emitting materials having different emission wavelengths are used for one or both of the light-emitting layer 120 and the light-emitting layer 170, light having different emission peaks is synthesized, and thus the emission spectrum of the light-emitting element 250 has at least two maxima.

[0294] The above structure is suitable for obtaining white light emission. By making the light of the light-emitting layer 120 and the light-emitting layer 170 be in a complementary color relationship, white light emission can be obtained. It is particularly preferable to select host materials in such a way as to achieve white light emission with high color rendering or at least have light emission of red, green, and blue.

[0295] In addition, in a light-emitting element in which three or more light-emitting units are stacked, the light-emitting colors of the host materials for the respective light-emitting units may be the same or different. In the case where the light-emitting element includes a plurality of light-emitting units that emit light of the same color, light with a higher intensity can be emitted at a lower current value. This structure is suitable for adjusting the light-emitting color. It is particularly preferable for cases where host materials with different light-emitting efficiencies and different light-emitting colors are used. For example, in the case where three light-emitting units are provided, by providing two light-emitting units containing a fluorescent material that exhibits the same light-emitting color and one light-emitting unit containing a phosphorescent material that exhibits a different light-emitting color from the fluorescent material, the light-emitting intensities of fluorescent light and phosphorescent light can be adjusted. In other words, the intensity of the light-emitting color can be adjusted according to the number of light-emitting units.

[0296] In the case of adopting the above-described light-emitting element including two fluorescent light-emitting units and one phosphorescent light-emitting unit, in order to efficiently obtain white light emission, the following structures are preferably adopted: a light-emitting element including two light-emitting units containing a blue fluorescent material and one light-emitting unit containing a yellow phosphorescent material, a light-emitting element including two light-emitting units containing a blue fluorescent material and one light-emitting layer unit containing a red phosphorescent material and a green phosphorescent material, or a light-emitting element including two light-emitting units containing a blue fluorescent material and one light-emitting layer unit containing a red phosphorescent material, a yellow phosphorescent material, and a green phosphorescent material.

[0297] In addition, at least one of the light-emitting layer 120 and the light-emitting layer 170 may be further divided into layers and each layer may contain different light-emitting materials. That is to say, at least one of the light-emitting layer 120 and the light-emitting layer 170 may also be formed of two or more layers. For example, in the case where a light-emitting layer is formed by sequentially stacking a first light-emitting layer and a second light-emitting layer from the hole-transporting layer side, a material having hole-transporting properties may be used as the host material of the first light-emitting layer, and a material having electron-transporting properties may be used as the host material of the second light-emitting layer. In this case, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be the same or different materials. In addition, the light-emitting materials contained in the first light-emitting layer and the second light-emitting layer may be materials having the function of emitting light of the same color, or may be materials having the function of emitting light of different colors. By adopting a structure of a plurality of light-emitting materials having the function of emitting light of different colors from each other, white light emission with high color rendering properties composed of three primary colors or four or more light-emitting colors can also be obtained.

[0298] In addition, the light-emitting layer of the light-emitting unit 108 preferably contains a phosphorescent compound. Note that when at least one of the plurality of units contains an organometallic complex according to one aspect of the present invention, a light-emitting element with high light-emitting efficiency and reliability can be provided.

[0299] This embodiment can be appropriately combined with other embodiments.

[0300] (Embodiment 5) In this embodiment, with reference to Figure 3A and Figure 3B a light-emitting device using the light-emitting elements described in Embodiment 3 and Embodiment 4 will be described.

[0301] Figure 3A is a top view showing the light-emitting device, Figure 3B is a cross-sectional view cut along Figure 3A A - B and C - D in. The light-emitting device includes a drive circuit unit (source-side drive circuit) 601, a pixel unit 602, and a drive circuit unit (gate-side drive circuit) 603, which are used to control the light emission of the light-emitting element and are represented by dotted lines. In addition, reference numeral 604 is a sealing substrate, reference numeral 625 is a desiccant, reference numeral 605 is a sealant, and the inner side surrounded by the sealant 605 is a space 607.

[0302] In addition, the guiding wiring 608 is a wiring for transmitting signals input to the source-side drive circuit 601 and the gate-side drive circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, etc. from an FPC (flexible printed circuit) 609 serving as an external input terminal. In addition, although only the FPC is illustrated here, a printed wiring board (PWB: Printed Wiring Board) may be mounted on the FPC. The light-emitting device in this specification includes not only the light-emitting device main body, but also the light-emitting device on which the FPC or PWB is mounted.

[0303] Next, with reference to Figure 3B the cross-sectional structure of the above-described light-emitting device will be described. A drive circuit unit and a pixel unit are formed on the element substrate 610, and one pixel in the source-side drive circuit 601 and the pixel unit 602, which are the drive circuit units, is shown here.

[0304] In addition, in the source-side drive circuit 601, a CMOS circuit combining an n-channel TFT 623 and a p-channel TFT 624 is formed. In addition, the drive circuit may be formed using various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment, although a driver integrated type in which the drive circuit is formed on the substrate is shown, it is not necessary to adopt this structure, and the drive circuit may be formed externally instead of on the substrate.

[0305] In addition, the pixel unit 602 is formed of pixels including a switching TFT 611, a current control 612, and a first electrode 613 electrically connected to its drain. In addition, an insulator 614 is formed so as to cover the end portion of the first electrode 613. The insulator 614 may be formed using a positive-type photosensitive resin film.

[0306] In addition, in order to improve the coverage rate of the film formed on the insulator 614, the upper end or the lower end of the insulator 614 is formed into a curved surface with a curvature. For example, when a photosensitive acrylic resin is used as the material of the insulator 614, it is preferable that only the upper end of the insulator 614 has a curved surface. The radius of curvature of this curved surface is 0.2 μm or more and 0.3 μm or less. In addition, as the insulator 614, a negative photosensitive material or a positive photosensitive material can be used.

[0307] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, as the material of the first electrode 613 used as an anode, a material with a large work function is preferably used. For example, in addition to single-layer films such as ITO films, indium tin oxide films containing silicon, indium oxide films containing 2 wt% or more and 20 wt% or less of zinc oxide, titanium nitride films, chromium films, tungsten films, Zn films, Pt films, etc., a laminated film composed of a titanium nitride film and a film mainly composed of aluminum and a three-layer laminated film composed of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film can also be used. Note that when a laminated structure is adopted, the wiring resistance is also low, good ohmic contact can be obtained, and it can be used as an anode.

[0308] In addition, the EL layer 616 is formed by various methods such as vapor deposition using a vapor deposition mask, inkjet method, spin coating method, etc. As the material constituting the EL layer 616, a low molecular compound or a high molecular compound (including oligomers, dendrimers) can also be used.

[0309] In addition, as the material of the second electrode 617 formed on the EL layer 616 and used as a cathode, a material with a small work function (Al, Mg, Li, Ca, or their alloys and compounds, MgAg, MgIn, AlLi, etc.) is preferably used. Note that when the light generated in the EL layer 616 is transmitted through the second electrode 617, the second electrode 617 is preferably a laminate composed of a thin metal film and a transparent conductive film (ITO, indium oxide containing 2 wt% or more and 20 wt% or less of zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.).

[0310] In addition, the light-emitting element 618 is formed by the first electrode 613, the EL layer 616, and the second electrode 617. The light-emitting element 618 preferably has the structure shown in Embodiment 3 and Embodiment 4. In addition, the pixel portion includes a plurality of light-emitting elements, and the light-emitting device of the present embodiment may also include both light-emitting elements having the structure described in Embodiment 3 and Embodiment 4 and light-emitting elements having other structures.

[0311] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 using a sealant 605, a light-emitting element 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. In addition, the space 607 is filled with a filler, and in addition to being filled with an inert gas (such as nitrogen or argon), it may sometimes be filled with a resin or a drying material, or both a resin and a drying material.

[0312] As the sealant 605, an epoxy resin or glass powder is preferably used. In addition, these materials are preferably materials that do not allow moisture or oxygen to pass through as much as possible. Furthermore, as the material for the sealing substrate 604, in addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, acrylic resin, or the like can also be used.

[0313] Through the above method, a light-emitting device using the light-emitting elements described in Embodiment 3 and Embodiment 4 can be obtained.

[0314] <Structural Example 1 of Light-Emitting Device> In FIG. 4, an example of a light-emitting device in which a light-emitting element that emits white light and a coloring layer (color filter) are formed is shown as an example of a display device.

[0315] Figure 4A The substrate 1001, the base insulating film 1002, the gate insulating film 1003, the gate electrodes 1006, 1007, 1008, the first interlayer insulating film 1020, the second interlayer insulating film 1021, the peripheral portion 1042, the pixel portion 1040, the driving circuit portion 1041, the first electrodes 1024W, 1024R, 1024G, 1024B of the light-emitting element, the partition wall 1026, the EL layer 1028, the second electrode 1029 of the light-emitting element, the sealing substrate 1031, the sealant 1032, etc. are shown.

[0316] In addition, in Figure 4A , Figure 4B a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) is provided on a transparent substrate 1033. In addition, a black layer (black matrix) 1035 can also be provided. The transparent substrate 1033 provided with the coloring layer and the black layer is aligned and fixed on the substrate 1001. In addition, the coloring layer and the black layer are covered with a covering layer 1036. In addition, in Figure 4A , a light-emitting layer that does not transmit light through the coloring layer but transmits light to the outside and a light-emitting layer that transmits light through each color of the coloring layer and transmits light to the outside are shown. The light that does not pass through the coloring layer becomes white light, and the light that passes through the coloring layer becomes red light, blue light, and green light. Therefore, an image can be presented with four-color pixels.

[0317] Figure 4B An example is shown in which a red coloring layer 1034R, a green coloring layer 1034G, and a blue coloring layer 1034B are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. As Figure 4B shown, the coloring layer may also be provided between the substrate 1001 and the sealing substrate 1031.

[0318] In addition, although the light-emitting device described above uses a structure (bottom emission type) in which light is emitted from the side of the substrate 1001 on which the TFT is formed, a structure (top emission type) in which light is emitted from the side of the sealing substrate 1031 may also be used.

[0319] <Structural Example 2 of Light-Emitting Device> Figure 5 A cross-sectional view of a top emission type light-emitting device is shown. In this case, a substrate that does not transmit light can be used as the substrate 1001. The process up to the formation of the connection electrode connecting the TFT and the anode of the light-emitting element is carried out in the same manner as in the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed so as to cover the electrode 1022. This insulating film may also have a planarizing function. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film 1021 or various other materials.

[0320] Although the first lower electrode 1025W, the lower electrode 1025R, the lower electrode 1025G, and the lower electrode 1025B of the light-emitting element are anodes here, they may also be cathodes. In addition, in Figure 5 the top emission type light-emitting device shown, it is preferable that the lower electrode 1025W, the lower electrode 1025R, the lower electrode 1025G, and the lower electrode 1025B are reflective electrodes. In addition, it is preferable that the second electrode 1029 has a function of emitting light and transmitting light. In addition, it is preferable to adopt a microcavity structure between the second electrode 1029 and the lower electrode 1025W, the lower electrode 1025R, the lower electrode 1025G, and the lower electrode 1025B to amplify light of a specific wavelength. The structure of the EL layer 1028 adopts the structure as described in Embodiment 3 and Embodiment 4, and an element structure capable of obtaining white light emission is adopted.

[0321] In Figure 4A 、 Figure 4B and Figure 5 , a structure of the EL layer capable of obtaining white light emission can be realized by using a plurality of light-emitting layers or a plurality of light-emitting units, etc. Note that the structure for obtaining white light emission is not limited to this.

[0322] When adopting as Figure 5In the case of the top emission structure shown, a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) can be used for sealing. A black layer (black matrix) 1030 can be provided on the sealing substrate 1031 between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black layer (black matrix) 1030 can also be covered with a covering layer. In addition, a substrate with light transmissivity is used as the sealing substrate 1031.

[0323] In addition, although an example of full-color display using four colors of red, green, blue, and white is shown here, it is not limited thereto, and full-color display can also be performed using three colors of red, green, and blue. In addition, full-color display can also be performed using four colors of red, green, blue, and yellow.

[0324] Through the above method, a light-emitting device using the light-emitting elements described in Embodiment 3 and Embodiment 4 can be obtained.

[0325] In addition, this embodiment can be appropriately combined with other embodiments.

[0326] (Embodiment 6) In this embodiment, an electronic device of one aspect of the present invention will be described.

[0327] Since one aspect of the present invention uses an organic EL light-emitting element, an electronic device with a flat surface, high luminous efficiency, and high reliability can be manufactured. In addition, through one aspect of the present invention, an electronic device with a curved surface, high luminous efficiency, and high reliability can be manufactured. In addition, by using the organic compound of one aspect of the present invention for this electronic device, an electronic device with high luminous efficiency and high reliability can be manufactured.

[0328] Examples of the electronic device include: a television device; a desktop or notebook personal computer; a display for a computer, etc.; a digital camera; a digital video camera; a digital photo frame; a mobile phone; a portable game machine; a portable information terminal; a sound reproduction device; a large game machine such as a pachinko machine, etc.

[0329] Figure 6A and Figure 6B The portable information terminal 900 shown includes a housing 901, a housing 902, a display unit 903, a hinge unit 905, etc.

[0330] The housing 901 and the housing 902 are connected together by the hinge unit 905. The portable information terminal 900 can be converted from a folded state ( Figure 6A ) to as Figure 6BThe unfolded state shown. Thus, the portability during carrying is good, and since it has a large display area, the visibility during use is high.

[0331] The portable information terminal 900 is provided with a flexible display unit 903 across the housing 901 and the housing 902 connected by the hinge portion 905.

[0332] The light-emitting device manufactured by one mode of the present invention can be used for the display unit 903. Thus, the portable information terminal can be manufactured with a high yield.

[0333] The display unit 903 can display at least one of file information, still images, moving images, etc. When file information is displayed on the display unit, the portable information terminal 900 can be used as an e-book reader.

[0334] When the portable information terminal 900 is unfolded, the display unit 903 is held in a state with a large radius of curvature. For example, the display unit 903 can be held in such a way that it includes a portion curved with a radius of curvature of 1 mm or more and 50 mm or less, preferably 5 mm or more and 30 mm or less. A part of the display unit 903 is continuously provided with pixels across the housing 901 and the housing 902, enabling curved surface display.

[0335] The display unit 903 is used as a touch panel and can be operated with a finger, a stylus, etc.

[0336] The display unit 903 is preferably composed of one flexible display. Thus, continuous display can be performed across the housing 901 and the housing 902. In addition, the housing 901 and the housing 902 can also be respectively provided with a display.

[0337] In order to prevent the angle formed by the housing 901 and the housing 902 from exceeding a predetermined angle when the portable information terminal 900 is unfolded, the hinge portion 905 preferably has a locking mechanism. For example, the locking angle (the angle at which further opening is not possible) is preferably 90° or more and less than 180°, typically, it can be 90°, 120°, 135°, 150°, or 175°, etc. Thus, the convenience, safety, and reliability of the portable information terminal 900 can be improved.

[0338] When the hinge portion 905 has the above locking mechanism, an excessive force applied to the display unit 903 can be suppressed, thereby preventing damage to the display unit 903. Thus, a highly reliable portable information terminal can be realized.

[0339] The housing 901 and the housing 902 can also include a power button, an operation button, an external connection port, a speaker, a microphone, etc.

[0340] Either the housing 901 or the housing 902 may be provided with a wireless communication module, and data can be transmitted and received through a computer network such as the Internet, a LAN (Local Area Network), or Wi-Fi (registered trademark).

[0341] Figure 6C The illustrated portable information terminal 910 includes a housing 911, a display unit 912, operation buttons 913, an external connection port 914, a speaker 915, a microphone 916, a camera 917, and the like.

[0342] The light-emitting device manufactured by one mode of the present invention can be used for the display unit 912. Thus, the portable information terminal can be manufactured with a high yield.

[0343] In the portable information terminal 910, a touch sensor is provided in the display unit 912. Various operations such as making a call or inputting text can be performed by touching the display unit 912 with a finger or a stylus.

[0344] In addition, by operating the operation buttons 913, the power can be turned on and off or the type of the image displayed on the display unit 912 can be switched. For example, the screen for writing an email can be switched to the main menu screen.

[0345] In addition, by providing a detection device such as a gyro sensor or an acceleration sensor inside the portable information terminal 910, the direction (portrait or landscape) of the portable information terminal 910 can be determined, and the screen display direction of the display unit 912 can be automatically switched. In addition, the switching of the screen display direction can also be performed by touching the display unit 912, operating the operation buttons 913, or inputting sound using the microphone 916.

[0346] The portable information terminal 910 has, for example, one or more functions selected from a telephone, a notebook, an information reading device, and the like. Specifically, the portable information terminal 910 can be used as a smart phone. The portable information terminal 910 can execute various application programs such as a mobile phone, an email, reading and editing of articles, music playback, video playback, network communication, and computer games.

[0347] Figure 6D The illustrated camera 920 includes a housing 921, a display unit 922, operation buttons 923, a shutter button 924, and the like. In addition, a detachable lens 926 is mounted on the camera 920.

[0348] The light-emitting device manufactured by one mode of the present invention can be used for the display unit 922. Thus, a highly reliable camera can be manufactured.

[0349] Here, although the camera 920 has a structure that allows the lens 926 to be detached from the housing 921 for replacement, the lens 926 and the housing 921 can also be formed integrally.

[0350] By pressing the shutter button 924, the camera 920 can capture still images or moving images. Additionally, the display unit 922 can also have the function of a touch panel, and imaging can be performed by touching the display unit 922.

[0351] Furthermore, the camera 920 can also be equipped with an additional flash device, viewfinder, etc. Additionally, these components can also be assembled in the housing 921.

[0352] Figure 7A is a perspective view showing the watch-type portable information terminal 9200, Figure 7B is a perspective view showing the watch-type portable information terminal 9201.

[0353] Figure 7A The shown portable information terminal 9200 can execute various application programs such as mobile phones, emails, reading and editing of texts, music playback, network communication, computer games, etc. Additionally, the display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. Additionally, the portable information terminal 9200 can perform short-range wireless communication based on communication standards. For example, by communicating with a wireless headset that can perform wireless communication, hands-free calls can be made. Additionally, the portable information terminal 9200 includes a connection terminal 9006, and data can be directly exchanged with other information terminals through a connector. Additionally, charging can also be performed through the connection terminal 9006. Additionally, the charging operation can also be performed using wireless power supply without passing through the connection terminal 9006.

[0354] Figure 7B The shown portable information terminal 9201 is different from Figure 7A the shown portable information terminal in that the display surface of the display unit 9001 is not curved. In addition, the outer shape of the display unit of the portable information terminal 9201 is non-rectangular (circular in Figure 7B ).

[0355] Figures 7C to 7E is a perspective view showing the foldable portable information terminal 9202. Additionally, Figure 7C is a perspective view of the state where the portable information terminal 9202 is unfolded, Figure 7D is a perspective view of the intermediate state when the portable information terminal 9202 is converted from one of the unfolded state and the folded state to the other, Figure 7E is a perspective view of the state where the portable information terminal 9202 is folded.

[0356] The portable information terminal 9202 has good portability in the folded state, and in the unfolded state, it has a strong overview display because it has a seamlessly spliced large display area. The display unit 9001 included in the portable information terminal 9202 is supported by three housings 9000 connected by a hinge 9055. By bending between the two housings 9000 through the hinge 9055, the portable information terminal 9202 can be reversibly changed from the unfolded state to the folded state. For example, the portable information terminal 9202 can be bent with a curvature radius of 1 mm or more and 150 mm or less.

[0357] Figure 8A It is a schematic diagram showing an example of a floor cleaning robot.

[0358] The floor cleaning robot 5100 includes a display 5101 on the top surface, a plurality of cameras 5102, brushes 5103, and operation buttons 5104 on the side surface. Although not shown, tires, suction ports, etc. are provided on the bottom surface of the floor cleaning robot 5100. In addition, the floor cleaning robot 5100 also includes various sensors such as infrared sensors, ultrasonic sensors, acceleration sensors, piezoelectric sensors, optical sensors, and gyro sensors. In addition, the floor cleaning robot 5100 includes a wireless communication unit.

[0359] The floor cleaning robot 5100 can automatically walk, detect garbage 5120, and suck the garbage from the suction port on the bottom surface.

[0360] In addition, the floor cleaning robot 5100 analyzes the images captured by the cameras 5102 and can judge the presence or absence of obstacles such as walls, furniture, or steps. In addition, when an object such as wiring that may be wound around the brush 5103 is detected through image analysis, the rotation of the brush 5103 can be stopped.

[0361] The remaining battery power, the amount of sucked garbage, etc. can be displayed on the display 5101. In addition, the walking path of the floor cleaning robot 5100 can also be displayed on the display 5101. In addition, the display 5101 can be a touch panel, and the operation buttons 5104 can be displayed on the display 5101.

[0362] The floor cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. The images captured by the cameras 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the floor cleaning robot 5100 can also know the situation of the room when going out. In addition, the display content of the display 5101 can be confirmed using a portable electronic device such as a smartphone.

[0363] The light-emitting device of one embodiment of the present invention can be used for the display 5101.

[0364] Figure 8B The shown robot 2100 includes an arithmetic unit 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a moving mechanism 2108.

[0365] The microphone 2102 has a function of detecting the voice of the user and surrounding voices, etc. In addition, the speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104.

[0366] The display 2105 has a function of displaying various information. The robot 2100 can display the information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may be a detachable information terminal, and by setting this information terminal at a predetermined position of the robot 2100, charging and data transmission and reception can be performed.

[0367] The upper camera 2103 and the lower camera 2106 have a function of photographing the surrounding environment of the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of an obstacle in front when the robot 2100 moves using the moving mechanism 2108. The robot 2100 can recognize the surrounding environment using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107 and move safely.

[0368] The light-emitting device of one aspect of the present invention can be used for the display 2105.

[0369] Figure 8C It is a diagram showing an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, operation keys 5005 (including a power switch or an operation switch), connection terminals 5006, a sensor 5007 (which has a function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, inclination, vibration, odor, or infrared rays), a microphone 5008, a second display unit 5002, a support unit 5012, headphones 5013, etc.

[0370] The light-emitting device of one aspect of the present invention can be used for the display unit 5001 and the second display unit 5002.

[0371] Figure 9A and Figure 9BThe foldable portable information terminal 5150 is shown. The foldable portable information terminal 5150 includes a housing 5151, a display area 5152, and a bending portion 5153. Figure 9A The portable information terminal 5150 in the unfolded state is shown. Figure 9B The portable information terminal 5150 in the folded state is shown. Although the portable information terminal 5150 has a large display area 5152, by folding the portable information terminal 5150, the portable information terminal 5150 becomes smaller and has good portability.

[0372] The display area 5152 can be folded in half by the bending portion 5153. The bending portion 5153 is composed of a stretchable member and a plurality of support members. When folding, the stretchable member is stretched, and the folding is performed in such a manner that the bending portion 5153 has a radius of curvature of 2 mm or more, preferably 5 mm or more.

[0373] In addition, the display area 5152 can also be a touch panel (input / output device) provided with a touch sensor (input device). The light-emitting device of one aspect of the present invention can be used for the display area 5152.

[0374] This embodiment can be appropriately combined with other embodiments.

[0375] (Embodiment 7) In this embodiment, with reference to FIGS. 10 and Figure 11 an example of applying the light-emitting element of one aspect of the present invention to various lighting devices is described. By using the light-emitting element of one aspect of the present invention, a lighting device with high luminous efficiency and reliability can be manufactured.

[0376] By forming the light-emitting element of one aspect of the present invention on a flexible substrate, an electronic device or a lighting device having a light-emitting area on a curved surface can be realized.

[0377] In addition, a light-emitting device applying the light-emitting element of one aspect of the present invention can also be applied to the lighting of an automobile, which is provided on a windshield, a ceiling, etc.

[0378] Figure 10A A perspective view of one surface of the multifunctional terminal 3500 is shown, Figure 10B A perspective view of another surface of the multifunctional terminal 3500 is shown. In the multifunctional terminal 3500, a display unit 3504, a camera 3506, a lighting 3508, etc. are assembled in a housing 3502. The light-emitting device of one aspect of the present invention can be used for the lighting 3508.

[0379] The illumination 3508 of the light-emitting device including one embodiment of the present invention is used as a surface light source. Therefore, unlike point light sources typified by LEDs, low-directivity light emission can be obtained. For example, when the illumination 3508 and the camera 3506 are used in combination, the camera 3506 can be used to take pictures while the illumination 3508 is lit or flashing. Since the illumination 3508 has the function of a surface light source, pictures can be obtained as if taken under natural light.

[0380] Note that Figure 10A and Figure 10B the multifunctional terminal 3500 shown and Figures 7A to 7C the electronic device shown can similarly have various functions.

[0381] In addition, a speaker, a sensor (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, inclination, vibration, odor, or infrared rays), a microphone, etc. can be provided inside the housing 3502. In addition, by providing a detection device having sensors such as a gyroscope and an acceleration sensor for detecting inclination inside the multifunctional terminal 3500, the direction (portrait or landscape) of the multifunctional terminal 3500 can be determined and the screen display of the display unit 3504 can be automatically switched.

[0382] In addition, the display unit 3504 can also be used as an image sensor. For example, by touching the display unit 3504 with a palm or a finger, palm prints, fingerprints, etc. can be taken for personal identification. In addition, by providing a backlight or a sensing light source that emits near-infrared light in the display unit 3504, finger veins, palm veins, etc. can also be taken. Note that a light-emitting device according to one embodiment of the present invention can be applied to the display unit 3504.

[0383] Figure 10C A perspective view of a security light 3600 is shown. The lamp 3600 includes an illumination 3608 on the outside of the housing 3602, and a speaker 3610 etc. are assembled to the housing 3602. A light-emitting element according to one embodiment of the present invention can be used for the illumination 3608.

[0384] The lamp 3600 can emit light, for example, when the illumination 3608 is grasped or held. In addition, an electronic circuit capable of controlling the light-emitting method of the lamp 3600 can be provided inside the housing 3602. As this electronic circuit, for example, a circuit capable of realizing single or intermittent multiple light emissions or a circuit capable of adjusting the light amount of light emission by controlling the current value of light emission can be used. In addition, a circuit that emits a loud alarm sound from the speaker 3610 while the illumination 3608 emits light can also be assembled.

[0385] Since the lamp 3600 can emit light in all directions, it can emit light or emit light and sound to intimidate criminals and the like. In addition, the lamp 3600 may include a camera such as a digital still camera having a photographing function.

[0386] Figure 11 This is an example of using a light-emitting element for the indoor lighting device 8501. In addition, since the light-emitting element can be made large in area, a large-area lighting device can also be formed. In addition, a lighting device 8502 having a curved light-emitting area can be formed by using a housing having a curved surface. Since the light-emitting element shown in this embodiment is in a thin-film shape, the degree of freedom in the design of the housing is high. Therefore, a lighting device capable of corresponding to various designs can be formed. Also, a large lighting device 8503 can be provided on the interior wall surface. In addition, a touch sensor can be provided in the lighting device 8501, the lighting device 8502, and the lighting device 8503 to turn on or off the power supply.

[0387] In addition, by using the light-emitting element on the surface side of the table, a lighting device 8504 having the function of a table can be provided. In addition, by using the light-emitting element for a part of other furniture, a lighting device having the function of furniture can be provided.

[0388] As described above, by applying the light-emitting device of one aspect of the present invention, a lighting device and an electronic device can be obtained. Note that the lighting device and the electronic device are not limited to those shown in this embodiment, and can be applied to electronic devices in various fields.

[0389] The structure shown in this embodiment can be implemented in appropriate combination with the structures shown in other embodiments. [Example 1]

[0390] In this example, a method for synthesizing tris{2-[1-(2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}iridium(III) (abbreviation: [Ir(pni-diBup)3]) which is one aspect of the organometallic complex of the present invention represented by the structural formula (100) in Embodiment 1 will be described.

[0391] <Step 1; Synthesis of 2,6-diisobutylaniline> Place 100 g (617 mmol) of 2,6-dichloroaniline, 230 g (2256 mmol) of isobutylboronic acid, 479 g (2256 mmol) of tripotassium phosphate, 10 g (24.7 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos), and 3000 mL of toluene into a 5000 mL three-necked flask. Replace the air in the flask with nitrogen, and while reducing the pressure inside the flask, stir to degas the mixture. After degassing, add 11 g (11.5 mmol) of tris(dibenzylideneacetone)dipalladium(0), and stir at 120 °C for 12 hours under a nitrogen stream. After the specified time has elapsed, filter the resulting reaction solution by suction. Purify the resulting filtrate by extraction with toluene. Then, purify by silica gel column chromatography. Use a developing solvent of hexane:toluene = 15:1. Concentrate the resulting fractions to obtain 79 g of a black oily substance of the target product with a yield of 62%. The synthesis scheme of Step 1 is represented by the following formula (A-1).

[0392] [Chemical formula 51]

[0393] <Step 2; Synthesis of 2-nitronaphthalene-1-trifluoromethanesulfonate> Place 35 g (182 mmol) of 2-nitro-1-naphthol, 500 mL of dehydrated dichloromethane, and 51 mL (365 mmol) of triethylamine into a 1000 mL three-necked flask. Replace the air in the flask with nitrogen and cool to 0 °C. Here, dropwise add 40 mL (243 mmol) of trifluoromethanesulfonic anhydride (abbreviation: Tf2O), stir at 0 °C for 1 hour, and stir at room temperature for 20 hours. After the specified time has elapsed, add 300 mL of water and 30 mL of 1 M hydrochloric acid to the resulting mixture. Then, purify the mixture by extraction with dichloromethane. Then, purify by silica gel column chromatography. Use a developing solvent of hexane:dichloromethane = 5:1. Concentrate the resulting fractions to obtain 47 g of a yellow oily substance of the target product with a yield of 80%. The synthesis scheme of Step 2 is represented by the following formula (A-2).

[0394] [Chemical formula 52]

[0395] <Step 3; Synthesis of N-(2,6-diisobutylphenyl)-2-nitro-1-naphthylamine> Put 30 g (146 mmol) of 2,6-diisobutylaniline synthesized in Step 1, 47 g (146 mmol) of 2-nitronaphthalene-1-trifluoromethanesulfonate synthesized in Step 2, 81 g (248 mmol) of cesium carbonate, and 750 mL of toluene into a 2000 mL three-necked flask. Replace the air in the flask with nitrogen, and while reducing the pressure inside the flask, stir to degas the mixture. After degassing, add 4.8 g (11.7 mmol) of S-phos and 2.7 g (2.9 mmol) of tris(dibenzylideneacetone)dipalladium(0), and stir at 130 °C for 28 hours under a nitrogen stream. After the specified time, refine the resulting reaction mixture by extraction with toluene. Then, refine it by silica gel column chromatography. Use a developing solvent of hexane:ethyl acetate = 15:1. Concentrate the resulting fraction to obtain 13 g of a yellow oil in a yield of 23%. The synthesis scheme of Step 3 is represented by the following formula (A-3).

[0396] [Chemical formula 53]

[0397] <Step 4; Synthesis of N-(2,6-diisobutylphenyl)-1,2-naphthalenediamine> Put 13 g (34 mmol) of N-(2,6-diisobutylphenyl)-2-nitro-1-naphthylamine synthesized in Step 3, 6.1 mL (0.34 mol) of water, and 400 mL of ethanol into a 1000 mL three-necked flask and stir. Add 32 g (0.17 mol) of tin(II) chloride to the mixture and stir at 80 °C for 5 hours under a nitrogen stream. After the specified time, pour the resulting reaction mixture into 500 mL of 2M aqueous sodium hydroxide solution and stir at room temperature for 2 hours. Filter the precipitated precipitate by suction and wash it with chloroform to obtain a filtrate. Refine the resulting filtrate by extraction with chloroform. Then, refine it by silica gel column chromatography. Use a developing solvent of hexane:ethyl acetate = 15:1. Concentrate the resulting fraction to obtain 9.5 g of a black oil of the target product in a yield of 81%. The synthesis scheme of Step 4 is represented by the following formula (A-4).

[0398] [Chemical formula 54]

[0399] <Step 5; Synthesis of 1-(2,6-diisobutylphenyl)-2-phenyl-1H-naphtho[1,2-d]imidazole (abbreviation: Hpni-diBup)> 9.5 g (27 mmol) of N-(2,6-diisobutylphenyl)-1,2-naphthalenediamine synthesized in Step 4, 100 mL of acetonitrile, and 2.9 g (27 mmol) of benzaldehyde were placed in a 300 mL eggplant-shaped flask and stirred at 100 °C for 6 hours. 0.044 g (0.274 mmol) of iron(III) chloride was added to the mixture and stirred at 100 °C for 16 hours. After the specified time, the resulting reaction mixture was extracted with ethyl acetate. The resulting oily substance, 100 mL of toluene, and 10 g of manganese(IV) oxide were placed in a 300 mL eggplant-shaped flask and stirred at 130 °C for 7 hours. After the specified time, the resulting reaction mixture was suction filtered through diatomaceous earth (Wako Pure Chemical Industries, Ltd., Japan, catalog number: 537-02305) / magnesium silicate (Wako Pure Chemical Industries, Ltd., Japan, catalog number: 066-05265) / aluminum oxide. The resulting filtrate was concentrated to obtain an oily substance. The resulting oily substance was purified by silica gel column chromatography. Toluene was used as the developing solvent. The resulting fractions were concentrated, and thus 7.9 g of a white solid of the target product was obtained in a yield of 66%. The synthesis scheme of Step 5 is represented by the following formula (A-5).

[0400] [Chemical formula 55]

[0401] <Step 6; Synthesis of di-μ-chloro-tetrakis{2-[1-(2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}diiridium(III) (abbreviation: [Ir(pni-diBup)2Cl]2)> 3.3 g (7.7 mmol) of 1-(2,6-diisobutylphenyl)-2-phenyl-1H-naphtho[1,2-d]imidazole (abbreviation: Hpni-diBup) synthesized in Step 5, 1.6 g (3.7 mmol) of iridium(III) chloride monohydrate, 30 mL of 2-ethoxyethanol, and 10 mL of water were placed in a 100 mL round-bottomed flask, and the air in the flask was replaced with argon. The reaction was induced by irradiating the reaction vessel with microwaves (2.45 GHz, 100 W) for 2 hours. After the reaction, the reaction solution was suction filtered, and thus 2.8 g of a yellow solid of the target product was obtained in a yield of 69%. The synthesis scheme of Step 6 is represented by the following formula (A-6).

[0402] [Chemical formula 56]

[0403] <Step 7; Tris{2-[1-(2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3Synthesis of Phenyl-κC Iridium(III) (Abbreviation: [Ir(pni-diBup)3]) 2.0 g (0.92 mmol) of di-μ-chloro-tetra{2-[1-(2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}diiridium(III) (Abbreviation: [Ir(pni-diBup)2Cl]2) synthesized by the method of Step 6 and 150 mL of dichloromethane were placed in a 500 mL three-necked flask and stirred under a nitrogen stream. A mixed solution of 0.72 g (2.8 mmol) of silver trifluoromethanesulfonate and 150 mL of methanol was added dropwise to the mixed solution, and the mixture was stirred in the dark for 3 days. After the reaction at the specified time, the reaction mixture was filtered through diatomaceous earth. The resulting filtrate was concentrated to obtain 2.7 g of a yellow solid. 2.7 g of the obtained solid, 50 mL of ethanol, and 1.6 g (3.7 mmol) of 1-(2,6-diisobutylphenyl)-2-phenyl-1H-naphtho[1,2-d]imidazole (Abbreviation: Hpni-diBup) synthesized by the method of Step 5 were placed in a 500 mL eggplant-shaped flask and heated under reflux in a nitrogen stream for 20 hours. After the reaction at the specified time, the reaction mixture was suction-filtered to obtain a solid. The obtained solid was dissolved in dichloromethane and suction-filtered through diatomaceous earth / neutral silica gel / diatomaceous earth. The resulting filtrate was concentrated to obtain a solid. The obtained solid was purified by silica gel column chromatography. The developing solvent used was dichloromethane:hexane = 1:3. The obtained fractions were concentrated to obtain a solid. The obtained solid was recrystallized with ethyl acetate / hexane to obtain 1.1 g of a solid in a yield of 40%. The synthesis scheme is represented by the following formula (A-7).

[0404] [Chemical Formula 57]

[0405] The obtained 1.1 g of solid was purified by gradient sublimation. The obtained solid was heated at 340 °C for 41 hours under a pressure of 2.6 Pa and an argon flow rate of 10.5 mL / min for sublimation purification. After sublimation purification, 0.93 g of a yellow solid was obtained with a recovery rate of 88%.

[0406] Proton NMR ( 1 H-NMR) measurement was performed on the yellow solid obtained in the above step. The values obtained are shown below. In addition, Figure 12 shown 1 the H-NMR spectrum. It can be seen from Figure 12 that [Ir(pni-diBup)3], an organometallic complex of one embodiment of the present invention, was obtained.

[0407] 1 1H-NMR. δ(CD2Cl2): 0.15 (d, 9H), 0.39 - 0.42 (m, 18H), 0.59 (d, 9H), 1.27 - 1.35 (m, 3H), 1.78 - 1.86 (m, 3H), 1.93 - 2.02 (m, 6H), 2.33 (d, 6H), 6.35 - 6.40 (m, 6H), 6.56 - 6.61 (m, 6H), 7.04 - 7.07 (m, 6H), 7.16 (t, 3H), 7.25 (d, 3H), 7.30 (t, 3H), 7.40 (d, 3H), 7.48 (d, 3H), 7.63 (t, 3H), 7.73 (d, 3H).

[0408] Next, the ultraviolet-visible absorption spectrum (simply referred to as the "absorption spectrum" below) and the emission spectrum of the [Ir(pni-diBup)3] solution were measured. When measuring the absorption spectrum, using an ultraviolet-visible spectrophotometer (manufactured by JASCO Corporation, model V550), a deoxygenated dichloromethane solution (0.0089 mmol / L) of [Ir(pni-diBup)3] was placed in a quartz cell and measured at room temperature. In addition, when measuring the emission spectrum and the luminescence quantum yield, using an absolute PL quantum yield measurement device (manufactured by Hamamatsu Photonics K.K., Japan, model C11347-01), in a glove box (manufactured by Bright Corporation, Japan, LABstar M13(1250 / 780)), a deoxygenated dichloromethane solution (0.0089 mmol / L) was placed in a quartz cell under a nitrogen atmosphere, sealed, and measured at room temperature. Figure 13 The measurement results of the obtained absorption spectrum and emission spectrum are shown. The horizontal axis represents the wavelength, and the vertical axis represents the absorption intensity and the luminescence intensity. In addition, Figure 13 The absorption spectrum shown represents the result obtained by subtracting the absorption spectrum measured by placing only dichloromethane in the quartz cell from the absorption spectrum measured by placing the deoxygenated dichloromethane solution in the quartz cell.

[0409] As Figure 13 shown, the iridium complex [Ir(pni-diBup)3] has luminescence peaks at 500 and 536 nm, and green luminescence is observed from the deoxygenated dichloromethane solution.

[0410] Furthermore, it can be known through measurement that the luminescence quantum yield in the deoxygenated dichloromethane solution at an excitation wavelength of 450 nm is extremely high, namely 98%. [Example 2]

[0411] In this embodiment, a method for synthesizing bis{2-[1-(2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}[2-(4-methyl-5-phenyl-2-pyridyl-κN 2 )phenyl-κC]iridium(III) (abbreviation: [Ir(pni-diBup)2(mdppy)]) of one embodiment of the present invention represented by the structural formula (101) in Embodiment 1 will be described.

[0412] <Step 1; Synthesis of bis{2-[1-(2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}[2-(4-methyl-5-phenyl-2-pyridyl-κN 2 )phenyl-κC]iridium(III) (abbreviation: [Ir(pni-diBup)2(mdppy)])> 1.3 g (0.9 mmol) of di-μ-chloro-tetrakis[2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]diiridium(III) (abbreviation: [Ir(mdppy)2Cl]2) and 180 mL of dichloromethane were placed in a 500 mL three-necked flask and stirred under a nitrogen stream. A mixed solution of 0.7 g (2.7 mmol) of silver trifluoromethanesulfonate and 35 mL of methanol was added dropwise to the mixed solution, and the mixture was stirred in the dark for 18 hours. After the reaction at the specified time, the reaction mixture was filtered through diatomaceous earth. The obtained filtrate was concentrated to obtain 1.9 g of a yellow solid. The obtained 1.9 g of yellow solid, 30 mL of methanol, 30 mL of ethanol, and 1.6 g (3.6 mmol) of Hpni-diBup were placed in a 300 mL eggplant-shaped flask and heated under reflux in a nitrogen stream for 23 hours. After the reaction at the specified time, the reaction mixture was suction-filtered to remove insoluble matters, and then the filtrate was concentrated to obtain a solid. 60 mL of 1-butanol was added to the obtained solid, and the mixture was heated under reflux in a nitrogen stream for 22 hours. After the reaction at the specified time, the reaction mixture was suction-filtered to obtain a solid. The obtained solid was purified by silica gel column chromatography. As the developing solvent, a mixed solvent of hexane:dichloromethane = 3:1 was used. The obtained fractions were concentrated to obtain a solid. The obtained solid was recrystallized with ethyl acetate / hexane, and thus 0.20 g of a yellow solid of the target product was obtained at a yield of 9%. The synthesis scheme is represented by the following formula (B-1).

[0413] [Chemical formula 58]

[0414] The 0.19 g of the obtained solid was sublimation-refined by the gradient sublimation method. The obtained solid was heated at 320 °C for 18 hours under the conditions of a pressure of 2.5 Pa and an argon flow rate of 10.3 mL / min to perform sublimation-refinement. After sublimation-refinement, 0.14 g of a yellow solid was obtained with a recovery rate of 72%.

[0415] The yellow solid obtained in the above step was subjected to 1 1H-NMR measurement. The values obtained are shown below. In addition, Figure 14 shown 1 1H-NMR spectrum. It can be seen from Figure 14 that [Ir(pni-diBup)2(mdppy)] of an organometallic complex of one embodiment of the present invention was obtained.

[0416] 1 1H-NMR. δ(CD2Cl2): 0.09 - 0.15 (m, 9H), 0.29 - 0.34 (m, 9H), 0.40 (t, 1H), 0.45 (d, 3H), 0.51 (d, 3H), 1.18 - 1.24 (m, 1H), 1.34 - 1.49 (m, 1H), 1.70 - 1.78 (m, 1H), 1.88 - 2.09 (m, 6H), 2.17 - 2.25 (m, 2H), 2.51 (s, 3H), 6.30 - 6.40 (m, 3H), 6.48 (t, 1H), 6.61 - 6.52 (m, 3H), 6.64 - 6.69 (m, 2H), 6.74 - 6.79 (m, 2H), 6.83 (t, 1H), 6.93 - 7.01 (m, 3H), 7.08 (t, 1H), 7.13 - 7.25 (m, 8H), 7.34 - 7.51 (m, 6H), 7.57 - 7.73 (m, 4H), 7.87 (d, 1H), 7.94 (s, 1H), 8.31 (s, 1H).

[0417] Next, the absorption spectrum, emission spectrum, and luminescence quantum yield of a deoxygenated dichloromethane solution (0.0073 mmol / L) of [Ir(pni-diBup)2(mdppy)] were measured. The measurement was carried out in the same manner as in Example 1. Figure 15 The measurement results of the absorption spectrum and emission spectrum are shown.

[0418] As Figure 15 shown, the iridium complex [Ir(pni-diBup)2(mdppy)] has an emission peak at 530 nm, and green luminescence is observed from the deoxygenated dichloromethane solution.

[0419] In addition, through measurement, it can be known that the luminescence quantum yield in the deoxygenated dichloromethane solution (0.0073 mmol / L) at an excitation wavelength of 450 nm is extremely high, namely 98%. [Example 3]

[0420] In this example, a method for synthesizing tris{2-[1-(4-cyano-2-isobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}iridium(III) (abbreviation: [Ir(pni-iBuCNp)3]), which is a mode of the organometallic complex of one mode of the present invention represented by the structural formula (102) in Embodiment 1, will be described.

[0421] <Step 1; Synthesis of 4-amino-3-isobutylbenzonitrile> Put 75 g (492 mmol) of 4-amino-3-chlorobenzonitrile, 90 g (886 mmol) of isobutylboronic acid, 188 g (886 mmol) of tripotassium phosphate, 4.0 g (9.8 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos), and 2400 mL of toluene into a 5000 mL three-necked flask. Replace the air in the flask with nitrogen, and while reducing the pressure inside the flask, stir to degas the mixture. After degassing, add 4.5 g (4.9 mmol) of tris(dibenzylideneacetone)dipalladium(0), and stir at 120 °C for 20 hours under a nitrogen stream. After the specified time has passed, filter the resulting reaction solution. Refine the resulting filtrate by extraction with toluene. Then, refine it by silica gel column chromatography. Toluene is used as the developing solvent. Concentrate the resulting fractions to obtain 59 g of the target product as a brown oil with a yield of 69%. The synthesis scheme of Step 1 is represented by the following formula (C-1).

[0422] [Chemical formula 59]

[0423] <Step 2; Synthesis of 3-isobutyl-4-[N-(2-nitronaphthyl)amino]benzonitrile> Put 30 g (170 mmol) of 4-amino-3-isobutylbenzonitrile synthesized in Step 1, 45 g (141 mmol) of 2-nitronaphthalene-1-trifluoromethanesulfonate, 78 g (240 mmol) of cesium carbonate, and 750 mL of toluene into a 2000 mL three-necked flask. Replace the air in the flask with nitrogen, and while reducing the pressure inside the flask, stir to degas the mixture. After degassing, add 4.6 g (11 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos) and 2.6 g (2.8 mmol) of tris(dibenzylideneacetone)dipalladium(0), and stir at 130 °C for 24 hours under a nitrogen stream. After the specified time, refine the resulting reaction mixture by extraction with toluene. Then, refine it by silica gel column chromatography. Use a developing solvent of hexane:ethyl acetate = 10:1. Concentrate the resulting fractions to obtain 40 g of a yellow oil of the target product in a yield of 82%. The synthesis scheme of Step 2 is represented by the following formula (C-2).

[0424] [Chemical formula 60]

[0425] <Step 3; Synthesis of 3-isobutyl-4-[N-(1,2-naphthalenediamine)]benzonitrile> Put 40 g (115 mmol) of 3-isobutyl-4-[N-(2-nitronaphthyl)amino]benzonitrile synthesized in Step 2, 21 mL (1.2 mol) of water, and 1350 mL of ethanol into a 3000 mL three-necked flask and stir. Add 109 g (0.58 mol) of tin(II) chloride to the mixture, and stir at 80 °C for 6 hours under a nitrogen stream. After the specified time, pour the resulting reaction mixture into 500 mL of 2M aqueous sodium hydroxide solution, and stir at room temperature for 2 hours. Filter the precipitated precipitate by suction, and wash it with chloroform to obtain a filtrate. Refine the resulting filtrate by extraction with chloroform. Then, add hexane to the resulting solid and filter it by suction to obtain 32 g of a white solid in a yield of 88%. The synthesis scheme of Step 3 is represented by the following formula (C-3).

[0426] [Chemical formula 61]

[0427] <Step 4; Synthesis of 1-(4-cyano-2-isobutylphenyl)-2-phenyl-1H-naphtho[1,2-d]imidazole (abbreviation: Hpni-iBuCNp)> 32 g (101 mmol) of 3-isobutyl-4-[N-(1,2-naphthalenediamine)]benzonitrile synthesized in Step 3, 400 mL of acetonitrile, and 11 g (101 mmol) of benzaldehyde were placed in a 1000 mL three-necked flask and stirred at 100 °C for 6 hours. 0.16 g (1.0 mmol) of iron(III) chloride was added to the mixture and stirred at 100 °C for 16 hours. After the specified time, the resulting reaction mixture was extracted with ethyl acetate. Then, the resulting solid was purified by silica gel column chromatography. As the developing solvent, toluene was first used, and then a mixed solvent of toluene:ethyl acetate = 18:1 was used. The resulting fractions were concentrated to obtain a solid. Ethyl acetate was added to the resulting solid and suction filtered to obtain 14 g of a white solid of the target product in a yield of 34%. The synthesis scheme of Step 4 is represented by the following formula (C-4).

[0428] [Chemical formula 62]

[0429] <Step 5; Tris{2-[1-(4-cyano-2-isobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}iridium(III) (abbreviation: [Ir(pni-iBuCNp)3]) synthesis> 3.8 g (9.5 mmol) of 1-(4-cyano-2-isobutylphenyl)-2-phenyl-1H-naphtho[1,2-d]imidazole synthesized by the method of Step 4 and 0.93 g (1.9 mmol) of iridium(III) tris(acetylacetonate) were placed in a reaction vessel equipped with a three-way stopcock and heated at 250 °C for 40 hours. Dichloromethane was added to the resulting reaction mixture and the insoluble matter was removed. The resulting filtrate was concentrated to obtain a solid. The resulting solid was purified by silica gel column chromatography. Dichloromethane was used as the developing solvent. The resulting fractions were concentrated to obtain a solid. The resulting solid was recrystallized with ethyl acetate / hexane. Thus, 0.3 g of a yellow solid was obtained in a yield of 10%. The present synthesis scheme is represented by the following formula (C-5).

[0430] [Chemical formula 63]

[0431] Measure the mass (MS) of the yellow solid obtained in the above steps. The ESI-MS measurement results of the resulting compound are shown below. ESI-MS [M+H + = 1394.51 (Exact Mass = 1393.51). Thus, it was found that [Ir(pni-iBuCNp)3]) of one mode of the organometallic complex of the present invention represented by the above structural formula (102) was obtained.

[0432] Next, the absorption spectrum and emission spectrum of the deoxygenated dichloromethane solution (0.013 mmol / L) of [Ir(pni-iBuCNp)3] obtained in the above step were measured. The measurement was carried out in the same manner as in Example 1. Figure 16 The absorption spectrum and emission spectrum are shown.

[0433] As Figure 16 shown, the iridium complex [Ir(pni-iBuCNp)3] has emission peaks at 509 and 544 nm, and green luminescence is observed from the deoxygenated dichloromethane solution. [Example 4]

[0434] In this example, a method for synthesizing tris{2-[1-(4-cyano-2,6-diisobutylphenyl)-1H-naphtho[1,2-d]imidazol-2-yl-κN 3 phenyl-κC}iridium(III) (abbreviation: [Ir(pni-diBuCNp)3]) of one embodiment of the present invention represented by the structural formula (103) in Embodiment 1 is described.

[0435] [Step 1; Synthesis of 4-amino-3,5-diisobutylbenzonitrile] 58 g (310 mmol) of 4-amino-3,5-diisobutylbenzonitrile, 117 g (1145 mmol) of isobutylboronic acid, 243 g (1145 mmol) of tripotassium phosphate, 6.4 g (15.5 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos), and 1500 ml of toluene were placed in a 3000 mL three-necked reaction vessel. The air in the flask was replaced with nitrogen, and the mixture was stirred while reducing the pressure inside the flask to degas the mixture. After degassing, 5.7 g (6.2 mmol) of tris(dibenzylideneacetone)dipalladium(0) was added, and the mixture was stirred at 130 °C for 12 hours under a nitrogen stream. Toluene was added to the resulting reaction solution, and the solution was filtered through diatomaceous earth. The resulting filtrate was purified by extraction with toluene. Then, purification was carried out by silica gel column chromatography. Toluene was used as the developing solvent. The resulting fractions were concentrated to obtain 69 g of a yellow oil of the target product in a yield of 96%. The synthesis scheme of Step 1 is represented by the following formula (D-1).

[0436] [Chemical formula 64]

[0437] [Step 2; Synthesis of 3,5-diisobutyl-4-[N-(2-nitronaphthyl)amino]benzonitrile] Put 28 g (121 mmol) of 4-amino-3,5-diisobutylbenzonitrile synthesized in Step 1, 39 g (121 mmol) of 2-nitronaphthalene-1-trifluoromethanesulfonate, 67 g (205 mmol) of cesium carbonate, and 750 mL of toluene into a 2000 mL three-necked flask. Replace the air in the flask with nitrogen, and while reducing the pressure inside the flask, stir to degas the mixture. After degassing, add 4.0 g (9.7 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos) and 2.2 g (2.4 mmol) of tris(dibenzylideneacetone)dipalladium(0), and stir at 130 °C for 40 hours under a nitrogen stream. After the specified time, refine the resulting reaction mixture by extraction with toluene. Then, refine it by silica gel column chromatography. Use a developing solvent of hexane:ethyl acetate = 10:1. Concentrate the resulting fraction to obtain 4.5 g of an orange solid of the target product in a 9% yield. The synthesis scheme of Step 2 is represented by the following formula (D-2).

[0438] [Chemical formula 65]

[0439] <Step 3; Synthesis of 3,5-diisobutyl-4-[N-(1,2-naphthalenediamine)]benzonitrile> Put 4.5 g (11 mmol) of 3,5-diisobutyl-4-[N-(2-nitronaphthyl)amino]benzonitrile synthesized in Step 2, 2 mL (110 mmol) of water, and 130 mL of ethanol into a 500 mL three-necked flask and stir. Add 10.4 g (55 mmol) of tin(II) chloride to the mixture, and stir at 80 °C for 7.5 hours under a nitrogen stream. After the specified time, pour the resulting reaction mixture into 100 mL of 2M aqueous sodium hydroxide solution and stir at room temperature for 2 hours. Filter the precipitated precipitate by suction and wash it with chloroform to obtain a filtrate. Extract the resulting filtrate with chloroform. Then, concentrate the resulting extraction solution to obtain 4.1 g of a black oily substance of the target product in a 99% yield. The synthesis scheme of Step 3 is represented by the following formula (D-3).

[0440] [Chemical formula 66]

[0441] <Step 4; Synthesis of 1-(4-cyano-2,6-diisobutylphenyl)-2-phenyl-1H-naphtho[1,2-d]imidazole (abbreviation: Hpni-diBuCNp)> 4.2 g (11 mmol) of 3,5 - diisobutyl - 4 - [N - (1,2 - naphthalenediamine)]benzonitrile synthesized in Step 3, 50 mL of acetonitrile, and 1.2 g (11 mmol) of benzaldehyde were placed in a 500 mL three - necked flask and stirred at 100 °C for 8 hours. 18 mg (0.11 mmol) of iron(III) chloride was added to the mixture and stirred at 100 °C for 29 hours. After the specified time, the resulting reaction mixture was purified by extraction with ethyl acetate. Then, the resulting solid was purified by silica gel column chromatography. As the developing solvent, toluene was first used, and then a mixed solvent of toluene:ethyl acetate = 20:1 was used. The resulting fractions were concentrated to obtain 2.9 g of a black oily product of the target compound in a yield of 58%. The synthesis scheme of Step 4 is represented by the following formula (D - 4).

[0442] [Chemical formula 67]

[0443] <Step 5; Synthesis of tris{2 - [1 - (4 - cyano - 2,6 - diisobutylphenyl)-1H - naphtho[1,2 - d]imidazol - 2 - yl - κN 3 phenyl - κC}iridium(III) (abbreviation: [Ir(pni - diBuCNp)3])> 2.9 g (6.3 mmol) of 1 - (4 - cyano - 2,6 - diisobutylphenyl)-2 - phenyl - 1H - naphtho[1,2 - d]imidazole synthesized by the method of Steps 1 to 4 and 0.62 g (1.3 mmol) of iridium(III) tris(acetylacetonate) were placed in a reaction vessel equipped with a three - way stopcock and heated at 250 °C for 56 hours. Toluene was added to the resulting reaction mixture and filtered to remove insoluble substances. The resulting filtrate was concentrated to obtain a solid. The resulting solid was purified by silica gel column chromatography. Toluene was used as the developing solvent. The resulting fractions were concentrated to obtain a solid. The resulting solid was recrystallized from ethyl acetate / hexane to obtain 0.33 g of a yellow solid in a yield of 16%. The synthesis scheme is represented by the following formula (D - 5).

[0444] [Chemical formula 68]

[0445] The resulting 0.32 g of solid was purified by gradient sublimation. Sublimation purification was carried out by heating at 345 °C for 17 hours under the conditions of a pressure of 2.5 Pa and an argon flow rate of 10.4 mL / min. After sublimation purification, 0.10 g of a yellow solid was obtained with a recovery rate of 31%.

[0446] The yellow solid obtained in the above steps was 11H-NMR measurement. The values obtained are shown below. In addition, Figure 17 shows 1 the 1H-NMR spectrum. From Figure 17 it can be seen that [Ir(pni-diBuCNp)3] of an embodiment of the present invention is obtained.

[0447] 1 1H-NMR. δ (ppm from CH2Cl2), (CD2Cl2): -0.38 (d, 3H), -0.13--0.06 (m, 9H), 0.35 (d, 3H), 0.41-0.45 (m, 6H), 0.54-0.57 (m, 6H), 0.62-0.65 (m, 6H), 0.70 (d, 3H), 1.14-1.23 (m, 1H), 1.27-1.35 (m, 1H), 1.40-1.49 (m, 1H), 1.50-1.57 (m, 1H), 1.60-1.66 (m, 2H), 1.71-1.90 (m, 4H), 2.06-2.15 (m, 2H), 2.22-2.31 (m, 4H), 2.33-2.42 (t, 2H), 6.32-6.39 (m, 3H), 6.53-6.85 (m, 12H), 6.96 (t, 2H), 7.06 (d, 1H), 7.10-7.37 (m, 9H), 7.66-7.83 (m, 9H).

[0448] Next, the absorption spectrum, emission spectrum, and luminescence quantum yield of a deoxygenated dichloromethane solution (0.0084 mmol / L) of [Ir(pni-diBuCNp)3] were measured. Figure 18 The measurement results of the absorption spectrum and emission spectrum are shown.

[0449] As Figure 18 shown, the iridium complex [Ir(pni-diBuCNp)3] has luminescence peaks at 510 and 547 nm, and green luminescence is observed from the deoxygenated dichloromethane solution.

[0450] In addition, it can be known by measurement that the luminescence quantum yield in the deoxygenated dichloromethane solution (0.0084 mmol / L) at an excitation wavelength of 450 nm is extremely high, i.e., 91%. [Example 5]

[0451] Measure the luminescence quantum yields of [Ir(pni - diBup)3], [Ir(pni - diBup)2(mdppy)], and [Ir(pni - diBuCNp)3] synthesized as described above. In addition, measure the luminescence quantum yield of (OC - 6 - 22)-tris{2 - [1 - (2,6 - diisobutylphenyl)-1H - benzimidazol - 2 - yl - κN 3 phenyl - κC}iridium(III) (abbreviation: fac - [Ir(pbi - diBup)3]). The measurement is carried out in the same manner as the method described in Example 1. Table 1 shows the results.

[0452] [Table 1] Material Name Quantum Yield (%) <![CDATA[fac-[Ir(pbi-diBup)3]]]> 88 <![CDATA[[Ir(pni-diBup)3]]]> 98 <![CDATA[[ir(pni-diBup)2(mdppy)]]]> 98 <![CDATA[[Ir(pni - diBuCNp)3]]]> 91

[0453] The difference in the structures of [Ir(pni - diBup)3] and fac - [Ir(pbi - diBup)3] of the organometallic complex according to one embodiment of the present invention is whether a fused - ring benzene ring is included at the g - position of the benzimidazole skeleton. As shown in Table 1, the luminescence quantum yield of the organometallic complex according to one embodiment of the present invention is high. In addition, it is also known that the luminescence quantum yield of the organometallic complex in which the ligand contains a 1H - naphtho[1,2 - d]imidazole skeleton is extremely high, that is, more than 90%. [Example 6]

[0454] In this example, manufacturing examples of a light - emitting element and a comparative light - emitting element including an organic compound according to one embodiment of the present invention and the characteristics of the light - emitting element are described. Figure 1A Show the stacked structure of the light - emitting element manufactured in this example. In addition, Table 2 shows the detailed content of the element structure. In addition, the organic compounds used in this example are shown below. For other organic compounds, refer to other embodiments or examples.

[0455] [Chemical formula 69]

[0456] [Table 2]

[0457] 《Manufacture of Comparative Light - Emitting Element 1》 As Electrode 101, a 70 - nm - thick ITSO film is formed on a glass substrate by sputtering. In addition, the electrode area of Electrode 101 is 4 mm 2 (2 mm × 2 mm). Then, as a pretreatment for forming a light - emitting element on the substrate, the substrate surface is cleaned with water, dried at 200 °C for 1 hour, and then subjected to UV - ozone treatment for 370 seconds. Then, the substrate is placed in a container maintained at 1 × 10 -4In a vacuum evaporation apparatus with a vacuum degree of about Pa, baking is performed at 170 °C for 30 minutes. Then, the substrate is cooled for about 30 minutes.

[0458] Next, as the hole injection layer 111, co-evaporation is performed on the electrode 101 such that the weight ratio of DBT3P-II: molybdenum(VI) oxide (MoO3) is 1:0.5 and the thickness is 40 nm.

[0459] Next, as the hole transport layer 112, PCCP is evaporated on the hole injection layer 111 such that the thickness is 20 nm.

[0460] As the light-emitting layer 140, co-evaporation is performed on the hole transport layer 112 such that the weight ratio of 4,6mCzP2Pm: PCCP: [Ir(ppy)3] is 0.6:0.4:0.1 and the thickness is 40 nm. In addition, in the light-emitting layer 140, [Ir(ppy)3] is a guest material that exhibits phosphorescent emission.

[0461] Next, as the electron transport layer 118(1), 4,6mCzP2Pm is evaporated on the light-emitting layer 140 such that the thickness is 20 nm. Next, as the electron transport layer 118(2), NBPhen is sequentially evaporated on the electron transport layer 118(1) such that the thickness is 10 nm.

[0462] Next, as the electron injection layer 119, LiF is evaporated on the electron transport layer 118 such that the thickness is 1 nm.

[0463] Next, as the electrode 102, aluminum (Al) is formed on the electron injection layer 119 such that the thickness is 200 nm.

[0464] Next, in a glove box under a nitrogen atmosphere, a substrate different from the substrate on which the light-emitting element is formed (opposite substrate) is fixed to the substrate on which the light-emitting element is formed and sealed using a sealant, thereby sealing the comparative light-emitting element 1. Specifically, a desiccant is attached to the opposite substrate, and furthermore, the opposite substrate coated with the sealant and the glass substrate on which the light-emitting element is formed are attached near the range where the light-emitting element is formed, and ultraviolet light with a wavelength of 365 nm and an intensity of 6 J / cm 2 is irradiated, and heated at 80 °C for 1 hour. The comparative light-emitting element 1 is obtained through the above process.

[0465] 《Manufacture of Comparative Light-Emitting Element 2, Comparative Light-Emitting Element 3, and Light-Emitting Element 4》 The difference between the manufacturing processes of the comparative light-emitting element 2, the comparative light-emitting element 3, and the light-emitting element 4 and the manufacturing process of the above-described comparative light-emitting element 1 lies only in the manufacturing process of the light-emitting layer 140, and the other manufacturing processes are the same as those of the comparative light-emitting element 1. Since the element structures of the comparative light-emitting element 2, the comparative light-emitting element 3, and the light-emitting element 4 are as shown in Table 2, the detailed content of the manufacturing process is omitted. In addition, the light-emitting layer 140 of the comparative light-emitting element 2, the comparative light-emitting element 3, and the light-emitting element 4 is formed by a vacuum evaporation method in the same manner as that of the comparative light-emitting element 1.

[0466] The difference in the element structures of the comparative light-emitting element 1 to the comparative light-emitting element 3 and the light-emitting element 4 lies only in the host material for the light-emitting layer 140, and the other structures are the same. In addition, the light-emitting element 4 uses [Ir(pni-diBup)3] of an organic compound according to one embodiment of the present invention, and the comparative light-emitting element 3 uses a comparative substance fac-[Ir(pbi-diBup)3]. In addition, as the comparative light-emitting element 1 and the comparative light-emitting element 2, [Ir(ppy)3] and GD270 (manufactured by Jilin OLED Optoelectronic Materials Co., Ltd.), which are widely used as host materials, are used respectively.

[0467] <Characteristics of the light-emitting element> Next, the characteristics of the above-manufactured comparative light-emitting element 1 to the comparative light-emitting element 3 and the light-emitting element 4 were measured. A color luminance meter (manufactured by Topcon Corporation, BM-5A) was used for the measurement of luminance and CIE chromaticity, and a multi-channel spectral analyzer (manufactured by Hamamatsu Photonics K.K., Japan, PMA-11) was used for the measurement of electroluminescence spectra.

[0468] Figure 19 The current efficiency-luminance characteristics of the comparative light-emitting element 1 to the comparative light-emitting element 3 and the light-emitting element 4 are shown. In addition, Figure 20 The current density-voltage characteristics are shown. In addition, Figure 21 The external quantum efficiency-luminance characteristics are shown. In addition, each light-emitting element was measured at room temperature (in an atmosphere maintained at 23°C). In addition, Figure 22 The emission spectra when a current is passed through the comparative light-emitting element 1 to the comparative light-emitting element 3 and the light-emitting element 4 at a current density of 2.5 mA / cm 2 are shown.

[0469] In addition, Table 3 shows the element characteristics of the comparative light-emitting element 1 to the comparative light-emitting element 3 and the light-emitting element 4 around 1000 cd / m 2 .

[0470] [Table 3]

[0471] In addition, from Figure 22It can be seen that the emission spectra of Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 3 and Light-Emitting Element 4 have spectral peaks near 518 nm, 523 nm, 508 nm, and 500 nm, respectively, and the full widths at half maximum are about 74 nm, 73 nm, 63 nm, and 27 nm, respectively. Moreover, light emission from the host materials included in each light-emitting element can be obtained from Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 3 and Light-Emitting Element 4.

[0472] As Figure 19 shown in Table 3, Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 3 and Light-Emitting Element 4 all have high current efficiency. Although Light-Emitting Element 4 has an emission spectrum in a region with a lower luminous efficiency (short-wavelength region) compared to Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 3, it has the same current efficiency as Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 3. In addition, as Figure 21 shown in Table 3, Light-Emitting Element 4 has an extremely high external quantum efficiency, that is, exceeding 25%. In addition, the efficiency of Light-Emitting Element 4 is higher than that of Comparative Light-Emitting Element 1 and Comparative Light-Emitting Element 2 using [Ir(ppy)3] or GD270, which are widely used as host materials. In addition, it can also be known that Light-Emitting Element 4 emits light on the shorter-wavelength side compared to Light-Emitting Element 3, but its external quantum efficiency is equal to or higher than that of Light-Emitting Element 3.

[0473] As Figure 20 shown in Table 3, Comparative Light-Emitting Element 1 to Comparative Light-Emitting Element 3 and Light-Emitting Element 4 all have good driving voltage characteristics. [Example 7]

[0474] In this example, an example of manufacturing a light-emitting element including an organometallic complex according to one aspect of the present invention different from Example 6 and the characteristics of the light-emitting element are described. Figure 1A The stacked structure of the light-emitting element manufactured in this example is shown. In addition, Table 4 shows the detailed content of the element structure. In addition, the organic compounds used in this example are shown below. For other organic compounds, refer to other embodiments or examples.

[0475] [Chemical Formula 70]

[0476] [Table 4]

[0477] 《Manufacture of Light-Emitting Element 5》 The light-emitting element 5 is formed into a film by vacuum evaporation in the same manner as the above-described comparative light-emitting elements 1 to 3 and the light-emitting element 4. Since the element structure of the light-emitting element 5 is as shown in Table 4, the details of the manufacturing process are omitted. The light-emitting element 5 is a light-emitting element using a heteroleptic organometallic complex (a metal complex including two or more ligands) according to one embodiment of the present invention.

[0478] <Characteristics of the light-emitting element> Next, the characteristics of the above-manufactured light-emitting element 5 were measured. The measurement conditions of the light-emitting element were the same as those in the above-described embodiment.

[0479] Figure 23 The current efficiency-luminance characteristics of the light-emitting element 5 are shown. In addition, Figure 24 The current density-voltage characteristics are shown. In addition, Figure 25 The external quantum efficiency-luminance characteristics are shown. In addition, Figure 26 The emission spectrum when a current is passed through the light-emitting element 5 at a current density of 2.5 mA / cm 2 is shown.

[0480] In addition, Table 5 shows the element characteristics of the light-emitting element 5 at around 1000 cd / m 2 .

[0481] [Table 5]

[0482] In addition, it can be seen from Figure 26 that the emission spectrum of the light-emitting element 5 has a spectral peak at around 523 nm, the full width at half maximum is about 63 nm, and the light-emitting element 5 can obtain light emission from the guest material [Ir(pni-diBup)2(mdppy)].

[0483] As Figure 23 , Figure 25 and Table 5 show, the light-emitting element 5 has high current efficiency and high external quantum efficiency. In particular, the external quantum efficiency is extremely high, that is, it exceeds 25%.

[0484] As Figure 24 and Table 5 show, the light-emitting element 5 has good driving voltage characteristics. Emits light.

[0485] <Reliability of the light-emitting element> Next, a constant current drive test was performed on the light-emitting element 5 at 2 mA. Figure 27 The results are shown. It can be seen from Figure 27 that the LT 70 (30% brightness reduction time) of the light-emitting element 5 exceeds 100 hours, and the light-emitting element 5 has good reliability. [Example 8]

[0486] In this embodiment, an example of manufacturing a light-emitting element including an organometallic complex according to one aspect of the present invention and characteristics of the light-emitting element, which are different from those of Embodiment 6 and Embodiment 7, will be described. Figure 1A The stacked structure of the light-emitting element manufactured in this embodiment is shown. In addition, Table 6 shows the details of the element structure.

[0487] [Table 6]

[0488] "Manufacture of Comparative Light-Emitting Element 6 and Light-Emitting Element 7" For the manufacture of Comparative Light-Emitting Element 6 and Light-Emitting Element 7, film formation is performed by vacuum evaporation in the same manner as the above-described Light-Emitting Element 5. Since the element structures of Comparative Light-Emitting Element 6 and Light-Emitting Element 7 are as shown in Table 6, the details of the manufacturing process are omitted. Light-Emitting Element 7 is a light-emitting element using [Ir(pni-diBuCNp)3], an organometallic complex according to one aspect of the present invention, as a guest material. In addition, Comparative Light-Emitting Element 6 is a light-emitting element using GD270 as a guest material.

[0489] <Characteristics of Light-Emitting Element> Next, the characteristics of Comparative Light-Emitting Element 6 and Light-Emitting Element 7 manufactured above are measured. The measurement conditions of the light-emitting element are the same as those in the above-described embodiment.

[0490] Figure 28 The current efficiency-luminance characteristics of Comparative Light-Emitting Element 6 and Light-Emitting Element 7 are shown. In addition, Figure 29 The current density-voltage characteristics are shown. In addition, Figure 30 The external quantum efficiency-luminance characteristics are shown. In addition, Figure 31 It shows the emission spectra when a current is passed through Comparative Light-Emitting Element 6 and Light-Emitting Element 7 at a current density of 2.5 mA / cm 2 .

[0491] In addition, Table 7 shows the element characteristics of Comparative Light-Emitting Element 6 and Light-Emitting Element 7 in the vicinity of 1000 cd / m 2 .

[0492] [Table 7]

[0493] In addition, it can be seen from Figure 31 that the emission spectra of Comparative Light-Emitting Element 6 and Light-Emitting Element 7 have spectral peaks at around 523 nm and 510 nm, respectively, the full width at half maximum is about 68 nm and 67 nm, respectively, and Comparative Light-Emitting Element 6 and Light-Emitting Element 7 can obtain light emission from the guest materials included in the respective light-emitting elements.

[0494] AsFigure 28 , Figure 30 As shown in Figure 30 and Table 7, both the light-emitting element 6 and the light-emitting element 7 have high current efficiency. Although the light-emitting element 7 has an emission spectrum in a region with a lower luminous efficiency (short-wavelength region) compared to the comparative light-emitting element 6, it has a higher current efficiency than the comparative light-emitting element 6. In addition, from Figure 30 and Table 7, it can be seen that the light-emitting element 7 has an extremely high external quantum efficiency, that is, exceeding 25%. In addition, although the light-emitting element 7 emits light on the short-wavelength side compared to the comparative light-emitting element 6 that uses GD270 widely used as a host material, its current efficiency and external quantum efficiency are higher than those of the comparative light-emitting element 6.

[0495] From Figure 29 and Table 7, it can be seen that both the comparative light-emitting element 6 and the light-emitting element 7 have good driving voltage characteristics.

[0496] [Symbol Explanation]

[0497] 100: EL layer, 101: electrode, 102: electrode, 103: EL layer, 106: light-emitting unit, 108: light-emitting unit, 111: hole injection layer, 112: hole transport layer, 113: electron transport layer, 114: electron injection layer, 115: charge generation layer, 116: hole injection layer, 117: hole transport layer, 118: electron transport layer, 119: electron injection layer, 120: light-emitting layer, 140: light-emitting layer, 141: host material, 141_1: organic compound, 141_2: organic compound, 142: guest material, 150: light-emitting element, 152: light-emitting element, 170: light-emitting layer, 250: light-emitting element, 601: source-side driving circuit, 602: pixel portion, 603: gate-side driving circuit, 604: sealing substrate, 605: sealant, 607: space, 608: wiring, 610: element substrate, 611: TFT for switching, 612: for current control, 613: electrode, 614: insulator, 616: EL layer, 617: electrode, 618: light-emitting element, 623: n-channel TFT, 624: p-channel TFT, 900: portable information terminal, 901: housing, 902: housing, 903: display unit, 905: hinge portion, 910: portable information terminal, 911: housing, 912: display unit, 913: operation button, 914: external connection port, 915: speaker, 916: microphone, 917: camera, 920: camera, 921: housing, 922: display unit, 923: operation button, 924: shutter button, 926: lens, 1001: substrate, 1002: base insulating film, 1003: gate insulating film, 1006: gate electrode, 1007: gate electrode, 1008: gate electrode, 1020: interlayer insulating film, 1021: interlayer insulating film, 1022: electrode, 1024B: electrode, 1024G: electrode, 1024R: electrode, 1025B: lower electrode, 1025G: lower electrode, 1025R: lower electrode, 1026: partition wall, 1028: EL layer, 1029: electrode, 1031: sealing substrate, 1032: sealant, 1033: base material, 1034B: coloring layer, 1034G: coloring layer, 1034R: coloring layer, 1036: covering layer, 1037: interlayer insulating film, 1040: pixel portion, 1041: driving circuit portion, 1042: peripheral portion, 2100: robot, 2101: illuminance sensor, 2102: microphone, 2103: upper camera, 2104: speaker, 2105: display, 2106: lower camera, 2107: obstacle sensor, 2108: moving mechanism, 2110: arithmetic unit, 3500: multi-functional terminal, 3502: housing, 3504: display unit, 3506: camera, 3508: lighting, 3600: lamp, 3602: housing, 3608: lighting3610: Speaker, 5000: Housing, 5001: Display unit, 5002: Display unit, 5003: Speaker, 5004: LED lamp, 5005: Operation button, 5006: Connection terminal, 5007: Sensor, 5008: Microphone, 5012: Support part, 5013: Headphone, 5100: Floor cleaning robot, 5101: Display, 5102: Camera, 5103: Brush, 5104: Operation button, 5120: Garbage, 5140: Portable electronic device, 5150: Portable information terminal, 5151: Housing, 5152: Display area, 5153: Bending part, 8501: Lighting device, 8502: Lighting device, 8503: Lighting device, 8504: Lighting device, 9000: Housing, 9001: Display unit, 9006: Connection terminal, 9055: Hinge, 9200: Portable information terminal, 9201: Portable information terminal, 9202: Portable information terminal,

Claims

1. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-1), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, wherein, R 1 to R 10 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms which is substituted or unsubstituted, an aryl group having 6 to 25 carbon atoms which is substituted or unsubstituted, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

2. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-6), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, wherein, R 1 to R 10 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group, Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

3. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-11), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, wherein, R 1 to R 10 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group, Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms; L represents a monoanionic ligand, and n represents 1 or 2.

4. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-2), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, wherein, R 1 to R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms which is substituted or unsubstituted, an aryl group having 6 to 25 carbon atoms which is substituted or unsubstituted, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group.

5. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-7), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, Among them, R 1 to R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group.

6. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-12), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, wherein, R 1 to R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group L represents a monoanionic ligand, and n represents 1 or 2.

7. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-3), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, Among them, R 11 , R 13 and R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group.

8. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-8), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, Wherein, R 11 , R 13 and R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group.

9. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, Wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by the general formula (G-13), wherein the first organic compound and the second organic compound are a combination that forms an exciplex, wherein, R 11 , R 13 and R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms which is substituted or unsubstituted, an aryl group having 6 to 25 carbon atoms which is substituted or unsubstituted, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a halogenated alkyl group. wherein L represents a monoanionic ligand, wherein n represents 1 or 2.

10. The light-emitting element according to any one of claims 4 to 9, Among them, R 11 and R 15 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms which is substituted or unsubstituted, and an aryl group having 6 to 25 carbon atoms which is substituted or unsubstituted. Among them, R 13 represents any one of hydrogen, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a halogenated alkyl group.

11. The light-emitting element according to any one of claims 3, 6, and 9, Among them, The monoanionic ligand is any one of a monoanionic bidentate chelating ligand having a β-diketone structure, a monoanionic bidentate chelating ligand having a carboxyl group, a monoanionic bidentate chelating ligand having a phenolic hydroxyl group, a monoanionic bidentate chelating ligand in which both coordination elements are nitrogen, and a bidentate ligand that forms a metal-carbon bond with iridium through cyclometalation.

12. The light-emitting element according to any one of claims 3, 6, and 9, Among them, The monoanionic ligand is any one of the following general formulas (L1) to (L9): wherein, R 21 to R 86 each independently represents any one of hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogen group, a vinyl group, a cyano 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, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and A 1 to A 13 each independently represents nitrogen, sp 2 hybridized carbon bonded to a hydrogen atom, and sp 2 hybridized carbon containing a substituent, where the substituent is any one of an alkyl group having 1 to 6 carbon atoms, a halogen group, a haloalkyl group having 1 to 6 carbon atoms, and a phenyl group.

13. The light-emitting element according to any one of claims 1 to 9, Among them, The haloalkyl group is trifluoromethyl.

14. The light-emitting element according to any one of claims 1 to 9, wherein the alkyl group is a branched alkyl group having 3 to 6 carbon atoms.

15. A light-emitting element, comprising: a pair of electrodes, and a light-emitting layer between the pair of electrodes, wherein the light-emitting layer contains a first organic compound, a second organic compound, and an organometallic complex represented by any one of the structural formulas (100) to (103), wherein the first organic compound and the second organic compound are a combination that forms an exciplex.

16. A light-emitting device, comprising: the light-emitting element according to any one of claims 1 to 9; and at least one of a color filter and a transistor.

17. An electronic device, comprising: the light-emitting element according to any one of claims 1 to 9; and at least one of a housing and a touch sensor.

18. A lighting device, comprising the light-emitting element according to any one of claims 1 to 9; and at least one of a housing and a touch sensor.

19. An organic compound represented by the general formula (g-1), Among them, R 1 to R 10 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 7 carbon atoms, a substituted or unsubstituted aryl group having 6 to 25 carbon atoms, a halogenated group, a cyano group, a nitro group, a carbonyl group, and a haloalkyl group Ar represents a substituted or unsubstituted aryl group having 6 to 25 carbon atoms.

20. The organic compound according to claim 19, Among them, Ar represents any one of the structural formulas (Ar-1) to (Ar-25):

21. The organic compound according to claim 19, Among them, Ar represents a substituted or unsubstituted phenyl group.

22. The organic compound according to claim 21, Among them, The substituent of the substituted phenyl group is an alkyl group having 1 to 6 carbon atoms.

23. The organic compound according to claim 21, Among them, The alkyl group is a branched alkyl group having 3 to 7 carbon atoms.

24. An organic compound represented by the structural formula (I-1), 25. An organic compound represented by the structural formula (I-2),

Images