organic compounds

Abstract

This invention provides novel organic compounds suitable as host materials for light-emitting devices, particularly for phosphorescent light-emitting devices. [Solution] The present invention provides an organic compound in which a carbazolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, or a diphenylamino group is bonded to the 3-position of an imidazophenantholidine via an arylene group, or an organic compound in which a diphenylamino group is bonded to the 3-position of a triazolophenantholidine via an arylene group.

Description

[Technical Field]

[0001] One aspect of the present invention relates to organic compounds, light-emitting elements, light-emitting devices, display modules, lighting modules, display devices, light-emitting devices, electronic devices, and lighting devices. However, one aspect of the present invention is not limited to the above-mentioned technical fields. One aspect of the present invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, one example of a technical field of one aspect of the present invention disclosed herein is a semiconductor device, a display device, a liquid crystal display device, a light-emitting device, a lighting device, a power storage device, a memory device, an imaging device, a method of driving them, or a method of manufacturing them. [Background technology]

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

[0003] Because these light-emitting devices are self-emissive, using them as pixels in a display offers advantages such as higher visibility compared to liquid crystal displays and the elimination of the need for a backlight, making them suitable elements for flat panel displays. Furthermore, displays using such light-emitting devices can be manufactured to be thin and lightweight, which is a significant advantage. Another characteristic is their extremely fast response speed.

[0004] Furthermore, since these light-emitting devices can form a light-emitting layer continuously in two dimensions, they can produce light in a planar manner. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs and LEDs, or line light sources such as fluorescent lamps, and therefore has high value as a planar light source, such as for lighting.

[0005] As described above, displays and lighting devices using light-emitting devices are suitable for application to various electronic devices, but research and development are underway to find light-emitting devices with even better characteristics. For example, Patent Document 1 discloses a configuration in which an imidazophenanthridine derivative is used as the host material for a phosphorescent light-emitting device, and Patent Document 2 discloses a triazolophenanthridine derivative. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2014-033195 [Patent Document 2] Japanese Patent Publication No. 2017-175128 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] In one aspect of the present invention, the objective is to provide a novel organic compound. Alternatively, in another aspect of the present invention, the objective is to provide a novel carrier transport layer material. Alternatively, in another aspect of the present invention, the objective is to provide a novel host material. Alternatively, in another aspect of the present invention, the objective is to provide a host material for a phosphorescent light-emitting device. Alternatively, in another aspect of the present invention, the objective is to provide a novel organic compound capable of producing a light-emitting device with high luminescence efficiency. Alternatively, in another aspect of the present invention, the objective is to provide an organic compound capable of providing a light-emitting device with a good lifespan.

[0008] Alternatively, another aspect of the present invention aims to provide a light-emitting device with high luminous efficiency. Alternatively, another aspect of the present invention aims to provide a light-emitting device, light-emitting apparatus, electronic device, and display device, respectively, with low power consumption. Alternatively, another aspect of the present invention aims to provide a highly reliable light-emitting device, light-emitting apparatus, electronic device, and display device, respectively.

[0009] Furthermore, the description of these objectives does not preclude the existence of other objectives. Moreover, one aspect of the present invention does not necessarily have to possess all of these objectives. Other objectives will become clear from the description in the specification, drawings, and claims, and can be extracted from the description in the specification, drawings, and claims.

[0010] The present invention only needs to solve one of the above-mentioned problems. [Means for solving the problem]

[0011] To solve the above problems, one aspect of the present invention provides an organic compound in which a carbazolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, or a diarylamino group is bonded to the 3-position of an imidazophenantholidine via an arylene group, or an organic compound in which a diarylamino group is bonded to the 3-position of a triazolophenantholidine via an arylene group.

[0012] In other words, one aspect of the present invention is an organic compound represented by the following general formula (G1).

[0013] [ka]

[0014] However, in the above general formula (G1), X represents nitrogen or substituted or unsubstituted carbon, and Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. Also, R 1 ~R 8Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group. Furthermore, A represents a substituted or unsubstituted diarylamino group when X is nitrogen, and when X is carbon, it represents one of the following: a substituted or unsubstituted diarylamino group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted dibenzofuranyl group.

[0015] Alternatively, in another aspect of the present invention, in the above configuration, the R 1 ~R 8 It is an organic compound in which hydrogen is present.

[0016] Alternatively, one aspect of the present invention is an organic compound represented by the following general formula (G2).

[0017] [ka]

[0018] However, in the above general formula (G2), Z represents oxygen or sulfur, and Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. Also, R 1 ~R 16 Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group.

[0019] Alternatively, in another aspect of the present invention, in the above configuration, the R 1 ~R 16 It is an organic compound in which hydrogen is present.

[0020] Alternatively, another aspect of the present invention is an organic compound represented by the following general formula (G3).

[0021] [ka]

[0022] However, in the above general formula (G3), Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. Also, R 1 to R 9 and R 20 to R 27 each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.

[0023] Alternatively, another aspect of the present invention is an organic compound in the above configuration, wherein the R 1 to R 9 and R 20 to R 27 are hydrogen.

[0024] Alternatively, another aspect of the present invention is an organic compound in the above configuration, wherein the Ar is any one of the following structural formulas (Ar-1) to (Ar-13).

[0025] [Chemical formula]

[0026] Alternatively, another aspect of the present invention is an organic compound in the above configuration, wherein Ar is a group represented by any one of the above structural formulas (Ar-1), (Ar-2), (Ar-7), (Ar-8), and (Ar-10).

[0027] Alternatively, another aspect of the present invention is an organic compound in the above configuration, wherein the Ar is a group represented by the above structural formula (Ar-1).

[0028] Alternatively, another aspect of the present invention is an organic compound represented by the following structural formula (100).

[0029] [Chemical formula]

[0030] Alternatively, another aspect of the present invention is an organic compound represented by the following structural formula (135).

[0031] [ka]

[0032] Alternatively, another aspect of the present invention is a material for a carrier transport layer of a light-emitting device, comprising any of the above-mentioned organic compounds.

[0033] Alternatively, another aspect of the present invention is a host material for a light-emitting device comprising any of the above organic compounds.

[0034] Alternatively, another aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer located between the anode and the cathode, wherein the EL layer has a light-emitting layer, and the light-emitting layer has a light-emitting material and the organic compound.

[0035] Alternatively, another aspect of the present invention is an electronic device having the above-mentioned light-emitting device and a sensor, an operating button, a speaker, or a microphone.

[0036] Alternatively, another aspect of the present invention is a light-emitting device having the above-mentioned light-emitting device and a transistor or a substrate.

[0037] Alternatively, another aspect of the present invention is a lighting device having the above-mentioned light-emitting device and a housing.

[0038] In this specification, the term "light-emitting device" includes image display devices that use light-emitting devices. Furthermore, modules to which connectors, such as anisotropic conductive films or TCPs (Tape Carrier Packages), are attached to light-emitting devices, modules to which printed circuit boards are provided at the end of TCPs, or modules to which ICs (integrated circuits) are directly mounted using the COG (Chip On Glass) method may also be included as light-emitting devices. Additionally, lighting fixtures may have light-emitting devices. [Effects of the Invention]

[0039] In one aspect of the present invention, a novel organic compound can be provided. Alternatively, in another aspect of the present invention, a novel carrier transport layer material can be provided. Alternatively, in another aspect of the present invention, a novel host material can be provided. Alternatively, in another aspect of the present invention, a host material suitably usable in phosphorescent light-emitting devices can be provided. Alternatively, in another aspect of the present invention, a novel organic compound can be provided that enables the fabrication of light-emitting devices with high luminescence efficiency. Alternatively, in another aspect of the present invention, an organic compound can be provided that enables the fabrication of light-emitting devices with a good lifespan.

[0040] Alternatively, in another aspect of the present invention, a light-emitting device with high luminous efficiency can be provided. Alternatively, in another aspect of the present invention, a light-emitting device, light-emitting apparatus, electronic device, and display device with low power consumption can be provided. Alternatively, in another aspect of the present invention, a highly reliable light-emitting device, light-emitting apparatus, electronic device, and display device can be provided.

[0041] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one embodiment of the present invention does not necessarily have to possess all of these effects. Other effects will become clear from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. [Brief explanation of the drawing]

[0042] [Figure 1] Figures 1A, 1B, and 1C are schematic diagrams of the light-emitting device. [Figure 2] Figures 2A and 2B are conceptual diagrams of an active matrix type light-emitting device. [Figure 3] Figures 3A and 3B are conceptual diagrams of an active matrix type light-emitting device. [Figure 4] Figure 4 is a conceptual diagram of an active matrix type light-emitting device. [Figure 5] Figures 5A and 5B are conceptual diagrams of a passive matrix type light-emitting device. [Figure 6] Figures 6A and 6B are diagrams representing lighting devices. [Figure 7] Figures 7A, 7B1, 7B2, and 7C are diagrams representing electronic devices. [Figure 8] Figures 8A, 8B, and 8C represent electronic devices. [Figure 9] Figure 9 is a diagram representing a lighting device. [Figure 10] Figure 10 is a diagram representing a lighting device. [Figure 11] Figure 11 is a diagram representing an in-vehicle display device and lighting system. [Figure 12] Figures 12A and 12B are diagrams representing electronic devices. [Figure 13] Figures 13A, 13B, and 13C are diagrams representing electronic devices. [Figure 14] Figures 14A and 14B are 1H NMR charts of DBTPIPt-II. [Figure 15] Figure 15 shows the absorption and emission spectra of DBTPIPt-II in a toluene solution. [Figure 16] Figure 16 shows the absorption and emission spectra of DBTPIPt-II in a thin film state. [Figure 17] Figures 17A and 17B are 1H NMR charts of CzPIPt. [Figure 18]Figure 18 shows the absorption and emission spectra of CzPIPt in a toluene solution. [Figure 19] Figure 19 shows the absorption and emission spectra of CzPIPt in a thin film state. [Figure 20] Figures 20A and 20B are 1H NMR charts of mDPhATPt. [Figure 21] Figure 21 shows the absorption and emission spectra of mDPhATPt in a toluene solution. [Figure 22] Figure 22 shows the absorption and emission spectra of mDPhATPt in a thin film state. [Figure 23] Figure 23 shows the luminance-current density characteristics of light-emitting device 1, light-emitting device 2, reference light-emitting device 1, and reference light-emitting device 2. [Figure 24] Figure 24 shows the current efficiency-luminance characteristics of light-emitting device 1, light-emitting device 2, comparative light-emitting device 1, and comparative light-emitting device 2. [Figure 25] Figure 25 shows the luminance-voltage characteristics of light-emitting device 1, light-emitting device 2, reference light-emitting device 1, and reference light-emitting device 2. [Figure 26] Figure 26 shows the current-voltage characteristics of light-emitting device 1, light-emitting device 2, comparison light-emitting device 1, and comparison light-emitting device 2. [Figure 27] Figure 27 shows the external quantum efficiency-luminance characteristics of light-emitting device 1, light-emitting device 2, comparative light-emitting device 1, and comparative light-emitting device 2. [Figure 28] Figure 28 shows the emission spectra of light-emitting device 1, light-emitting device 2, reference light-emitting device 1, and reference light-emitting device 2. [Figure 29] Figure 29 shows the normalized luminance-time variation characteristics of light-emitting device 1, light-emitting device 2, comparative light-emitting device 1, and comparative light-emitting device 2. [Figure 30] Figure 30 shows the luminance-current density characteristics of light-emitting device 3 and comparative light-emitting device 3. [Figure 31] Figure 31 shows the current efficiency-luminance characteristics of light-emitting device 3 and comparative light-emitting device 3. [Figure 32] Figure 32 shows the luminance-voltage characteristics of light-emitting device 3 and comparison light-emitting device 3. [Figure 33] Figure 33 shows the current-voltage characteristics of light-emitting device 3 and comparison light-emitting device 3. [Figure 34] Figure 34 shows the external quantum efficiency-luminance characteristics of light-emitting device 3 and comparative light-emitting device 3. [Figure 35] Figure 35 shows the luminance-power efficiency characteristics of light-emitting device 3 and comparative light-emitting device 3. [Figure 36] Figure 36 shows the emission spectra of light-emitting device 3 and comparison light-emitting device 3. [Figure 37] Figure 37 shows the luminance-current density characteristics of light-emitting device 4 and comparative light-emitting device 4. [Figure 38] Figure 38 shows the current efficiency-luminance characteristics of light-emitting device 4 and comparative light-emitting device 4. [Figure 39] Figure 39 shows the luminance-voltage characteristics of light-emitting device 4 and comparison light-emitting device 4. [Figure 40] Figure 40 shows the current-voltage characteristics of light-emitting device 4 and comparison light-emitting device 4. [Figure 41] Figure 41 shows the external quantum efficiency-luminance characteristics of light-emitting device 4 and comparative light-emitting device 4. [Figure 42] Figure 42 shows the luminance-power efficiency characteristics of light-emitting device 4 and comparative light-emitting device 4. [Figure 43] Figure 43 shows the emission spectra of light-emitting device 4 and comparison light-emitting device 4. [Figure 44] Figure 44 shows the luminance-current density characteristics of light-emitting device 5 and comparison light-emitting device 5. [Figure 45] Figure 45 shows the current efficiency-luminance characteristics of light-emitting device 5 and comparative light-emitting device 5. [Figure 46] Figure 46 shows the luminance-voltage characteristics of light-emitting device 5 and comparison light-emitting device 5. [Figure 47] Figure 47 shows the current-voltage characteristics of light-emitting device 5 and comparison light-emitting device 5. [Figure 48] Figure 48 shows the external quantum efficiency-luminance characteristics of light-emitting device 5 and comparative light-emitting device 5. [Figure 49] Figure 49 shows the luminance-power efficiency characteristics of light-emitting device 5 and comparative light-emitting device 5. [Figure 50] Figure 50 shows the emission spectra of light-emitting device 5 and comparison light-emitting device 5. [Modes for carrying out the invention]

[0043] The embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be interpreted as being limited to the contents of the embodiments shown below.

[0044] (Embodiment 1) This embodiment describes an organic compound according to one aspect of the present invention. The organic compound according to one aspect of the present invention is an organic compound represented by the following general formula (G1).

[0045] [ka]

[0046] However, in the above general formula (G1), X represents nitrogen or a substituted or unsubstituted carbon. If X is a substituted carbon, the substituent shall be one of the following: an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.

[0047] Furthermore, Ar represents a substituted or unsubstituted arylene group with 6 to 12 carbon atoms.

[0048] Also, R 1 ~R 8Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.

[0049] Furthermore, A represents a substituted or unsubstituted diarylamino group when X is nitrogen, and when X is carbon, it represents one of the following: a substituted or unsubstituted diarylamino group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted dibenzofuranyl group.

[0050] The aryl group of the diarylamino group mentioned above is a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, and specifically, these can be independently a phenyl group, a naphthyl group, a biphenyldiyl group, and a fluorenyl group.

[0051] Furthermore, in the organic compound represented by the above general formula (G1), R 1 ~R 8 Organic compounds in which hydrogen is present are cost-effective because they are easy to synthesize and the raw materials are readily available.

[0052] In addition, in the organic compound represented by the above general formula (G1), it is preferable that X is carbon and A is a dibenzothiophenyl group or a dibenzofuranyl group. In particular, it is preferable that the dibenzothiophenyl group or dibenzofuranyl group is bonded to Ar at the 4-position, and the organic compound represented by the following general formula (G2) is preferred.

[0053] [ka]

[0054] However, in the above general formula (G2), Z represents oxygen or sulfur.

[0055] Furthermore, Ar represents a substituted or unsubstituted arylene group with 6 to 12 carbon atoms.

[0056] R 1 ~R 16 Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group.

[0057] Furthermore, in the organic compound represented by the above general formula (G2), R 1 ~R 16 Organic compounds in which hydrogen is present are cost-effective because they are easy to synthesize and the raw materials are readily available.

[0058] Furthermore, the organic compound represented by the above general formula (G1) is preferable because it exhibits good hole transport properties when X is carbon and A is a carbazolyl group. In particular, it is preferable that the carbazolyl group is bonded to nitrogen Ar at position 9, that is, the organic compound represented by the following general formula (G3) is preferred.

[0059] [ka]

[0060] However, in the above general formula (G3), Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms.

[0061] Also, R 1 ~R 9 and R 20 ~R 27 Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group.

[0062] Furthermore, in the organic compound represented by the above general formula (G3), R 1 ~R 9 and R 20 ~R 27 Organic compounds in which hydrogen is present are cost-effective because they are easy to synthesize and the raw materials are readily available.

[0063] Furthermore, in the organic compounds represented by the above general formulas (G1) to (G3), examples of arylene groups having 6 to 12 carbon atoms represented as Ar include phenylene groups, naphthylene groups, and biphenyldiyl groups, and among these, organic compounds in which the group is represented by any of the following structural formulas (Ar-1) to (Ar-13) are preferred. In addition, Ar is particularly preferred to be a group represented by the following structural formulas (Ar-1), (Ar-2), (Ar-7), (Ar-8), and (Ar-10) because it yields a high synthesis yield and the raw materials are inexpensive, and among these, the group represented by the following structural formula (Ar-1) is particularly preferred.

[0064] [ka]

[0065] In this specification, when "substituted or unsubstituted" is used to describe a group or skeleton, possible substituents on the group or skeleton include C1 to C6 alkyl groups, C3 to C7 cyclic alkyl groups, and C6 to C13 aryl groups. These substituents may form a ring with adjacent substituents.

[0066] Furthermore, within this specification, examples of C1 to C6 alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, and hexyl groups. Examples of C3 to C7 cyclic alkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 1-methylcyclohexyl, 2,6-dimethylcyclohexyl, cycloheptyl, and cyclooctyl groups. Examples of C6 to C13 aryl groups include phenyl, naphthyl, biphenyl, and fluorenyl groups. Among the C1 to C6 alkyl groups, C3 to C7 cyclic alkyl groups, and C6 to C13 aryl groups, groups represented by the following structural formulas (R-2) to (R-32) are preferred.

[0067] [ka]

[0068] [ka]

[0069] An organic compound according to one embodiment of the present invention, having the above configuration, can be used in a light-emitting device to provide a light-emitting device with good luminescence efficiency. It can also provide a light-emitting device with a good lifespan. Furthermore, an organic compound according to one embodiment of the present invention is an organic compound that can be suitably used as a material for a carrier transport layer and a host material.

[0070] Specific examples of organic compounds having the above configuration are shown below.

[0071] [ka]

[0072] [ka]

[0073] [ka]

[0074] [ka]

[0075] [ka]

[0076] [ka]

[0077] Next, an example of a method for synthesizing an organic compound according to one aspect of the present invention will be given.

[0078] An organic compound according to one embodiment of the present invention, represented by the general formula (G1) above, can be obtained by coupling a halogenated or triflate-substituted compound (compound 1) of a 1,2,4-triazolo[4,3-f]phenanthridine derivative or imidazo[1,2-f]phenanthridine derivative with an organic boron compound or boronic acid (compound 2) having an aryl group containing a carbazolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, or a diarylamino group, via a Suzuki-Miyaura reaction, as shown in the synthesis scheme (A-1).

[0079] [ka]

[0080] In synthesis scheme (A-1), X represents nitrogen or carbon. If X is carbon, it may have substituents. Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. 1 ~R 8Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group. When X is N, A represents a substituted or unsubstituted diarylamino group, and when X is carbon, it represents a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzothiophenyl group, a substituted or unsubstituted dibenzofuranyl group, or a substituted or unsubstituted diarylamino group. In synthesis scheme (A-1), R 50 and R 51 Each of these independently represents either hydrogen or an alkyl group having 1 to 6 carbon atoms, and R 50 and R 51 They may be joined to each other to form a ring. Also, X 11 The symbol represents a halogen or triflate group.

[0081] When the reaction represented by synthesis scheme (A-1) is carried out by the Suzuki-Miyaura reaction, it is preferable to use a palladium catalyst. Examples of such palladium catalysts include palladium(II) acetate, tetrakis(triphenylphosphine)palladium(O), and bis(triphenylphosphine)palladium(II) dichloride, but other catalysts effective for this reaction may also be used. Ligands for the palladium catalyst that can be used in the above synthesis include tri(ortho-tolyl)phosphine, triphenylphosphine, and tricyclohexylphosphine. Other palladium catalyst ligands effective for this reaction may also be used.

[0082] It is preferable to use a base in the reaction of the above synthesis scheme (A-1). Examples of bases that can be used in this reaction include organic bases such as sodium tert-butoxide, and inorganic bases such as potassium carbonate and sodium carbonate, but other bases can also be used.

[0083] The reaction represented by synthesis scheme (A-1) is preferably carried out using a solvent. Suitable solvents for this reaction include mixed solvents of toluene and water, mixed solvents of toluene and alcohol (such as ethanol) and water, mixed solvents of xylene and water, mixed solvents of xylene and alcohol (such as ethanol) and water, mixed solvents of benzene and water, mixed solvents of benzene and alcohol (such as ethanol) and water, and mixed solvents of ethers (such as ethylene glycol dimethyl ether) and water. More preferably, a mixed solvent of toluene and water, or a mixed solvent of toluene, ethanol and water, or a mixed solvent of ethers such as ethylene glycol dimethyl ether and water is preferred. Other solvents effective for this reaction may also be used.

[0084] The Suzuki-Miyaura coupling reaction shown in the above synthesis scheme (A-1) uses an organoboron compound or a boronic acid as compound 2 in the cross-coupling reaction. However, other compounds such as organoaluminum, organozirconium, organozinc, and organotin compounds may also be used in the cross-coupling reaction.

[0085] Furthermore, in the synthesis scheme shown in synthesis scheme (A-1), a halogenated or triflate-substituted compound (compound 1) of a 1,2,4-triazolo[4,3-f]phenanthridine derivative or imidazo[1,2-f]phenanthridine derivative is reacted with an organoboron compound or boronic acid (compound 2) having an aryl group containing a carbazolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, or a diarylamino group. However, an organoboron compound or boronic acid of a 1,2,4-triazolo[4,3-f]phenanthridine derivative or imidazo[1,2-f]phenanthridine derivative may also be reacted with a halogenated or triflate-substituted compound having an aryl group containing a carbazolyl group, a dibenzothiophenyl group, a dibenzofuranyl group, or a diarylamino group.

[0086] An organic compound according to one embodiment of the present invention, represented by the general formula (G2) below, can be obtained by coupling a halogenated or triflate-substituted imidazo[1,2-f]phenanthridine derivative (compound 3) with an organoboron compound or boronic acid (compound 4) having a dibenzothiophenyl group or a dibenzofuranyl group, via the Suzuki-Miyaura reaction, as shown in the synthesis scheme (A-2).

[0087] [ka]

[0088] In synthesis scheme (A-2), Z represents oxygen or sulfur. Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. 1 ~R 9 Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group. 10 ~R 16 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. In synthesis scheme (A-2), R 52 and R 53 Each of these independently represents either hydrogen or an alkyl group having 1 to 6 carbon atoms, and R 52 and R 53 They may be joined to each other to form a ring. Also, X 12 represents a halogen or triflate group.

[0089] When carrying out synthesis scheme (A-2) via the Suzuki-Miyaura reaction, it is preferable to use a palladium catalyst. Examples of such palladium catalysts include palladium(II) acetate, tetrakis(triphenylphosphine)palladium(O), and bis(triphenylphosphine)palladium(II) dichloride, but other catalysts effective for this reaction may also be used. Ligands for the palladium catalyst that can be used in the above synthesis include tri(ortho-tolyl)phosphine, triphenylphosphine, and tricyclohexylphosphine. Other ligands for the palladium catalyst that are effective for this reaction may also be used.

[0090] It is preferable to use a base in the reaction represented by the above synthesis scheme (A-2). Examples of bases that can be used in this reaction include organic bases such as sodium tert-butoxide, and inorganic bases such as potassium carbonate and sodium carbonate, but other bases may also be used.

[0091] The reaction represented by synthesis scheme (A-2) is preferably carried out using a solvent. Suitable solvents for this reaction include mixed solvents of toluene and water, mixed solvents of toluene and an alcohol such as ethanol and water, mixed solvents of xylene and water, mixed solvents of xylene and an alcohol such as ethanol and water, mixed solvents of benzene and water, mixed solvents of benzene and an alcohol such as ethanol and water, and mixed solvents of ethers such as ethylene glycol dimethyl ether and water. More preferably, a mixed solvent of toluene and water, or a mixed solvent of toluene, ethanol and water, or a mixed solvent of ethers such as ethylene glycol dimethyl ether and water is used. Other solvents effective for this reaction may also be used.

[0092] The Suzuki-Miyaura coupling reaction shown in the above synthesis scheme (A-2) uses an organoboron compound or a boronic acid as compound 4 in the cross-coupling reaction. However, other compounds such as organoaluminum, organozirconium, organozinc, and organotin compounds may also be used in the cross-coupling reaction.

[0093] Furthermore, in the synthesis scheme shown in synthesis scheme (A-2), a halogenated or triflate-substituted imidazo[1,2-f]phenanthridine derivative (compound 3) is reacted with an organoboron compound or boronic acid (compound 4) of a dibenzothiophenyl group or dibenzofuranyl group. However, an organoboron compound or boronic acid of an imidazo[1,2-f]phenanthridine derivative may also be reacted with a halogenated or triflate-substituted imidazo[1,2-f]phenanthridine derivative.

[0094] An organic compound according to one embodiment of the present invention, represented by the general formula (G3) below, can be obtained by coupling a halogenated or triflate-substituted imidazo[1,2-f]phenanthridine derivative (compound 5) with a carbazole derivative (compound 6) via a Hartwick-Buchwald reaction, as shown in the synthesis scheme (A-3).

[0095] [ka]

[0096] In the synthesis scheme (A-3), Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. 1 ~R 9 Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group. 20 ~R 27Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Also, X 13 represents a halogen or triflate group.

[0097] When the reaction represented by synthesis scheme (A-3) is carried out by the Hartwick-Buchwald reaction, it is preferable to use a palladium catalyst, such as bis(dibenzylideneacetone)palladium(O) and palladium(II) acetate. In addition, ligands that can be used for the palladium catalyst in the above synthesis include tri(tert-butyl)phosphine, tri(n-hexyl)phosphine, and tricyclohexylphosphine.

[0098] It is preferable to use a base in the reaction represented by the synthesis scheme (A-3). Examples of bases that can be used in this reaction include organic bases such as sodium tert-butoxide and inorganic bases such as potassium carbonate.

[0099] Furthermore, the reaction represented by synthesis scheme (A-3) is preferably carried out using a solvent. Examples of solvents that can be used in this reaction include toluene, xylene, benzene, and tetrahydrofuran.

[0100] In addition to the Hartwick-Buchwald reaction, other reaction mechanisms such as the Ullmann reaction may also be used for the reaction shown in synthesis scheme (A-3).

[0101] An organic compound according to one embodiment of the present invention, represented by the general formula (G4) below, can be obtained by coupling a halogenated or triflate-substituted compound (compound 7) of a 1,2,4-triazolo[4,3-f]phenanthridine derivative or imidazo[1,2-f]phenanthridine derivative with a diarylamine derivative (compound 8) via a Hartwick-Buchwald reaction, as shown in the synthesis scheme (A-4).

[0102] [ka]

[0103] In synthesis scheme (A-4), X represents either nitrogen or carbon. If X is carbon, it may have substituents. Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. 1 and Ar 2 Each of these independently represents either a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. 1 ~R 8 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 3 to 7 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. Also, X 14 represents a halogen or triflate group.

[0104] When the reaction represented by synthesis scheme (A-4) is carried out by the Hartwick-Buchwald reaction, it is preferable to use a palladium catalyst, such as bis(dibenzylideneacetone)palladium(O) and palladium(II) acetate. In addition, ligands that can be used for the palladium catalyst in the above synthesis include tri(tert-butyl)phosphine, tri(n-hexyl)phosphine, and tricyclohexylphosphine.

[0105] It is preferable to use a base in the reaction represented by the synthesis scheme (A-4). Examples of bases that can be used in this reaction include organic bases such as sodium tert-butoxide and inorganic bases such as potassium carbonate.

[0106] Furthermore, the reaction represented by synthesis scheme (A-4) is preferably carried out using a solvent. Examples of solvents that can be used in this reaction include toluene, xylene, benzene, and tetrahydrofuran.

[0107] In addition to the Hartwick-Buchwald reaction, other reaction mechanisms such as the Ullmann reaction may also be used for the reaction shown in synthesis scheme (A-4).

[0108] The compounds shown in this embodiment can be used in appropriate combinations with the configurations shown in other embodiments.

[0109] (Embodiment 2) This embodiment describes a light-emitting device according to one aspect of the present invention.

[0110] Figure 1A shows a diagram representing a light-emitting device according to one embodiment of the present invention. The light-emitting device according to one embodiment of the present invention has a first electrode 101, a second electrode 102, and an EL layer 103. The EL layer 103 has the organic compound shown in Embodiment 1.

[0111] The EL layer 103 has an emissive layer 113, and the emissive layer 113 contains an emissive material. The organic compound described in Embodiment 1 is preferably used as a material for dispersing the emissive material in the emissive layer 113. The emissive layer 113 may also contain other materials.

[0112] Furthermore, the light-emitting layer 113 may be configured in which the organic compound described in Embodiment 1 and the hole transport material are co-deposited. In this case, the organic compound described in Embodiment 1 and the hole transport material may form an excited complex. By forming an excited complex with an appropriate emission wavelength, it is possible to achieve effective energy transfer to the light-emitting material and provide a light-emitting device with high efficiency and a good lifespan.

[0113] In Figure 1A, the EL layer 103 is shown to include a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115, in addition to the light-emitting layer 113. However, the configuration of the light-emitting device is not limited to these. It is not necessary to form any of these layers, and it may also have layers with other functions.

[0114] The organic compound described in Embodiment 1 has good electron transport properties and is therefore also effective when used in the electron transport layer 114.

[0115] Next, a detailed structure and examples of materials for the light-emitting device described above will be explained. In one embodiment of the present invention, as described above, the light-emitting device has an EL layer 103 consisting of multiple layers between a pair of electrodes, a first electrode 101 and a second electrode 102, and any portion of the EL layer 103 contains the organic compound disclosed in Embodiment 1.

[0116] The first electrode 101 is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a large work function (specifically, 4.0 eV or more). Specifically, examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium oxide (IWZO) containing tungsten oxide and zinc oxide. These conductive metal oxide films are usually deposited by sputtering, but they may also be fabricated using methods such as the sol-gel method. As an example of a fabrication method, indium zinc oxide can be formed by sputtering using a target containing 1 to 20 wt% zinc oxide relative to indium oxide. Indium oxide (IWZO) containing tungsten oxide and zinc oxide can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride). Graphene can also be used. Furthermore, by using the composite material described later in the layer in contact with the first electrode 101 in the EL layer 103, the electrode material can be selected regardless of the work function.

[0117] The EL layer 103 preferably has a multilayer structure. There are no particular limitations on the multilayer structure, and various layer structures such as hole injection layers, hole transport layers, light-emitting layers, electron transport layers, electron injection layers, carrier block layers, exciton block layers, and charge generation layers can be applied. In this embodiment, two types of configurations will be described: one having a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115, as shown in Figure 1A, and another having a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and a charge generation layer 116, as shown in Figure 1B. The materials constituting each layer are specifically described below.

[0118] The hole injection layer 111 is a layer containing an acceptor substance. Both organic and inorganic compounds can be used as the acceptor substance.

[0119] Examples of substances with acceptor properties include compounds having electron-withdrawing groups (halogen groups and cyano groups, etc.), such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and preferred. Furthermore, radialene derivatives having an electron-withdrawing group (especially halogen groups such as fluoro groups, and cyano groups, etc.) [3] are preferred because they have very high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenates[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates[2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds mentioned above, other substances with acceptor properties that can be used include oxides of transition metals such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide.In addition, the hole injection layer 111 can also be formed by phthalocyanine-based complex compounds such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrene sulfonic acid) (PEDOT / PSS). Accepting substances can extract electrons from adjacent hole transport layers (or hole transport materials) by applying an electric field.

[0120] Furthermore, a composite material containing the above-mentioned acceptor substance in a hole-transporting material can also be used as the hole injection layer 111. By using a composite material containing the acceptor substance in a hole-transporting material, it is possible to select the material for forming the electrode regardless of the work function. In other words, not only materials with a large work function but also materials with a small work function can be used as the first electrode 101.

[0121] Various organic compounds can be used as hole-transporting materials in composite materials, including aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers). -6 cm 2 It is preferable that the material has a hole mobility of / Vs or higher. Below, we specifically list organic compounds that can be used as hole transporting materials in composite materials.

[0122] Aromatic amine compounds that can be used in composite materials include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B). Specifically, carbazole derivatives include 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole Lubazole (abbreviated as PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert- Examples include butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, and 2,5,8,11-tetra(tert-butyl)perylene. In addition, pentacene, coronene, and the like can also be used. They may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviated as DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviated as DPVPA).

[0123] Furthermore, polymer compounds such as poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD) can also be used.

[0124] The hole-transporting material used in the composite material is more preferably one of the following: a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, it may be an aromatic amine having substituents including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. Furthermore, it is preferable that the second organic compound is a substance having an N,N-bis(4-biphenyl)amino group, as this allows for the creation of light-emitting devices with a good lifetime. Specifically, the second organic compounds mentioned above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), and 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8 -yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d] 4-Fran-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation :BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-Diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-Diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-Diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-Diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'- Binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenyl Nylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyl Triphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi(9H-fluorene)-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi(9H-fluoren)-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl) Riphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3- [9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,Examples include 9'-spirobio-9H-fluoren-1-amine.

[0125] Furthermore, it is even more preferable that the hole-transporting material used in the composite material has a relatively deep HOMO level between -5.7 eV and -5.4 eV. Having a relatively deep HOMO level in the hole-transporting material used in the composite material facilitates the injection of holes into the hole transport layer 112 and makes it easier to obtain a light-emitting device with a good lifetime.

[0126] Furthermore, by mixing alkali metal or alkaline earth metal fluoride into the above composite material (preferably with an atomic ratio of fluorine atoms of 20% or more in the layer), the refractive index of the layer can be reduced. This also makes it possible to form a layer with a low refractive index inside the EL layer 103, thereby improving the external quantum efficiency of the light-emitting device.

[0127] By forming the hole injection layer 111, the hole injection performance is improved, making it possible to obtain a light-emitting device with a low driving voltage. Furthermore, organic compounds with acceptor properties are easy to deposit and form films with, making them easy to use materials.

[0128] The hole transport layer 112 is formed by including a material having hole transport properties. The material having hole transport properties is 1 × 10 -6 cm 2It is preferable to have a hole mobility of / Vs or higher. Examples of materials having the above hole transport properties include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAF). LP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAN) B) Aromatic amino acids such as 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluoren]-2-amine (abbreviated as PCBASF). Compounds having a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Furthermore, the materials listed as having hole-transporting properties used in the composite material of the hole injection layer 111 can also be suitably used as materials constituting the hole transport layer 112.

[0129] The light-emitting layer 113 contains a light-emitting substance and a host material. The light-emitting layer 113 may also contain other materials. Furthermore, it may be a laminate of two layers with different compositions.

[0130] The luminescent material can be a fluorescent material, a phosphorescent material, a material that exhibits thermally activated delayed fluorescence (TADF), or any other luminescent material.

[0131] Examples of materials that can be used as fluorescent luminescent substances in the light-emitting layer 113 include 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-1,6-diamine (abbreviation: 1,6FLPAPrn), and N,N'-bis(3-methylphenyl) N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (Abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (Abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (Abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (Abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4- Phenylenediamine (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-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-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetra Sen (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphen Nyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-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]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-(pyre Examples include n-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds like 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they exhibit high hole-trapping properties and excellent luminescence efficiency and reliability. Other fluorescent materials can also be used.

[0132] In the light-emitting layer 113, when a phosphorescent material is used as the light-emitting substance, possible materials include, for example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazole-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1, Organometallic iridium complexes having a 4H-triazole skeleton, such as 2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), and tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1 Organometallic iridium complexes having a 1H-triazole skeleton, such as H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), and fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl Organometallic iridium complexes with an imidazole skeleton, such as nyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridineto]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), and bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2 '] Iridium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2 Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2Examples include organometallic iridium complexes that use phenylpyridine derivatives having electron-withdrawing groups, such as iridium(III) acetylacetonate (abbreviated as FIr(acac)), as ligands. These compounds exhibit blue phosphorescence and have emission spectral peaks between 440 nm and 520 nm.

[0133] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6- Organometallic iridium complexes having a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), organometallic iridium complexes having a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), and tris(2-phenylpyrimidinato-N,C 2’ Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinate-N,C) 2’Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinate)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinate)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinate-N,C) 2’ Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C) 2’ Examples include organometallic iridium complexes with a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviated as [Ir(pq)2(acac)]), and rare earth metal complexes, such as tris(acetylacetonate)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]). These compounds mainly exhibit green phosphorescence and have emission spectral peaks between 500 nm and 600 nm. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred due to their outstanding reliability and luminescence efficiency.

[0134] Furthermore, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and tris(1-phenylisoquinolinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C) 2’ Examples include organometallic iridium complexes with a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviated as [Ir(piq)2(acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviated as [Eu(TTA)3(Phen)]). These compounds exhibit red phosphorescence and have emission spectral peaks between 600 nm and 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton produce a red emission with good chromaticity.

[0135] In addition to the phosphorescent compounds described above, other known phosphorescent substances may be selected and used.

[0136] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc., can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can be used. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (SnF2(Proto IX)), mesoporphyrin-tin fluoride complexes (SnF2(Meso IX)), hematoporphyrin-tin fluoride complexes (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complexes (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complexes (SnF2(OEP)), etioporphyrin-tin fluoride complexes (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complexes (PtCl2OEP), as shown in the following structural formulas.

[0137] [ka]

[0138] Furthermore, the following structural formulas represent 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazol (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can also be used, such as PXZ-TRZ, 3-[4-(5-phenyl-5,10-dihydrophenadin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA). The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. Among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptor properties and are reliable. Furthermore, among the skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable, and therefore it is preferable to have at least one of these skeletons.Furthermore, a dibenzofuran skeleton is preferred as the furan skeleton, and a dibenzothiophene skeleton is preferred as the thiophene skeleton. In addition, as the pyrrole skeleton, indole skeleton, carbazole skeleton, indrocarbazole skeleton, bicarbazole skeleton, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole skeleton are particularly preferred. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because both the electron-donating and electron-accepting properties of the π-electron-rich heteroaromatic ring are strengthened, and the energy difference between the S1 and T1 levels is reduced, thus efficiently obtaining thermally activated delayed fluorescence. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. Furthermore, aromatic amine skeletons, phenazine skeletons, etc., can be used as the π-electron-rich skeleton. Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons represented by phenylborane and volanthrene, aromatic rings having a nitrile group or a cyano group represented by benzonitrile or cyanobenzene, heteroaromatic rings, carbonyl skeletons represented by benzophenone, phosphine oxide skeletons, sulfone skeletons, etc., can be used. In this way, π-electron-deficient skeletons and π-electron-excess skeletons can be used instead of at least one of π-electron-deficient heteroaromatic rings and π-electron-excess heteroaromatic rings.

[0139] [ka]

[0140] TADF materials are materials that have a small difference between the S1 and T1 energy levels and possess the ability to convert energy from triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy with only a small amount of thermal energy (reverse intersystem crossing), and singlet excited states can be efficiently generated. Furthermore, triplet excitation energy can be converted into luminescence.

[0141] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances has an extremely small difference between the S1 and T1 levels and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0142] Furthermore, the phosphorescence spectrum observed at low temperatures (e.g., 77K to 10K) can be used as an indicator of the T1 level. For TADF materials, when a tangent is drawn at the short-wavelength tail of the fluorescence spectrum and the energy at the wavelength of the extrapolation is taken as the S1 level, and when a tangent is drawn at the short-wavelength tail of the phosphorescence spectrum and the energy at the wavelength of the extrapolation is taken as the T1 level, it is preferable that the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0143] Furthermore, when using TADF material as a light-emitting material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0144] Various carrier transport materials can be used as the host material for the light-emitting layer, including materials with electron transport properties, materials with hole transport properties, and the TADF material mentioned above.

[0145] As materials having hole transport properties, organic compounds having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton are preferred. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl -3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4' Aromatic amine skeletons such as -di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobio[9H-fluoren]-2-amine (abbreviated as PCBASF). Compounds having the following characteristics: 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), and compounds having a carbazole skeleton such as 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,Examples include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviated as DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to reducing the driving voltage.

[0146] Preferred electron-transporting materials include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazollyl)phenolato]zinc(II) (abbreviated as ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviated as ZnBTZ), as well as organic compounds having a π-electron-deficient heteroaromatic ring skeleton.Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), and 9-[4-(5-phenyl-1,3, Heterocyclic compounds having a polyazole skeleton, such as 4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), and 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoki Sarin (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl Examples include heterocyclic compounds having a diazine skeleton, such as [4,6mDBTP2Pm-II]pyrimidine and 2,8-bis[3-(dibenzothiophen-4-yl)phenyl]-benzo[h]quinazoline (abbreviated as 4,8mDBtP2Bqn), and heterocyclic compounds having a pyridine skeleton, such as 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB). Among the above, heterocyclic compounds having a diazine skeleton or heterocyclic compounds having a pyridine skeleton are preferred due to their good reliability.In particular, heterocyclic compounds having a diazine (pyrimidine, pyrazine, etc.) skeleton exhibit high electron transport properties and contribute to reducing the driving voltage. The organic compound described in Embodiment 1 is an organic compound with electron transport properties and can be suitably used as a host material in the light-emitting layer.

[0147] The TADF materials listed above can be used as host materials. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing, and this energy is then transferred to the light-emitting material, thereby increasing the luminescence efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0148] This is particularly effective when the light-emitting material is a fluorescent material. Furthermore, in order to obtain high luminescence efficiency, it is preferable that the S1 level of the TADF material is higher than that of the fluorescent material. Also, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material.

[0149] Furthermore, it is preferable to use a TADF material that exhibits emission that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0150] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To achieve this, it is preferable that the fluorescent material has protecting groups around the luminescent phosphodiocyte (the skeleton that causes luminescence). Preferred protecting groups are substituents without π bonds, and saturated hydrocarbons are preferred. Specifically, examples include alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable to have multiple protecting groups. Substituents without π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphodiocyte of the fluorescent material with little effect on carrier transport and carrier recombination. Here, the luminescent phosphodiocyte refers to the atomic group (skeleton) that causes luminescence in the fluorescent material. The luminescent phosphodiosity preferably has a skeleton containing π bonds, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of condensed aromatic rings or condensed heteroaromatic rings include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, and phenothiazine skeletons. Fluorescent materials having naphthalene, anthracene, fluorene, chrysene, triphenylene, tetracene, pyrene, perylene, coumarin, quinacridone, or naphthobisbenzofuran skeletons are particularly preferred due to their high fluorescence quantum yield.

[0151] When using a fluorescent material as the light-emitting material, a material having an anthracene skeleton is preferred as the host material. Using a material having an anthracene skeleton as the host material for a fluorescent material makes it possible to realize a light-emitting layer with good luminescence efficiency and durability. Among the materials having an anthracene skeleton to be used as the host material, materials having a diphenylanthracene skeleton, and especially a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Furthermore, while a carbazole skeleton is preferred as the host material because it improves hole injection and transport, a benzocarbazole skeleton, in which a benzene ring is further condensed into carbazole, is even more preferred because the HOMO is about 0.1 eV shallower than carbazole, making it easier for holes to enter. In particular, a dibenzocarbazole skeleton is preferred as the HOMO is about 0.1 eV shallower than carbazole, making it easier for holes to enter, and it also has excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance that simultaneously possesses a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or dibenzocarbazole skeleton). Furthermore, from the viewpoint of hole injection and transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as CzPA), and 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole. Examples include ruvasol (abbreviated as cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviated as FLPPA), and 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth).In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good characteristics and are therefore preferred choices.

[0152] The host material may be a mixture of multiple substances, and when using a mixed host material, it is preferable to mix an electron-transporting material with a hole-transporting material. By mixing an electron-transporting material with a hole-transporting material, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The weight ratio of the hole-transporting material to the electron-transporting material should be 1:19 to 19:1. The organic compound described in Embodiment 1 can be suitably used as the electron-transporting material in the mixed host material. The mixing of the electron-transporting material and the hole-transporting material may be performed by co-deposition, or by depositing a pre-mixed sample. The organic compound described in Embodiment 1 is also suitable for the latter method of mixing.

[0153] Furthermore, phosphorescent materials can be used as part of the above-mentioned mixed materials. When a fluorescent material is used as the light-emitting material, the phosphorescent material can be used as an energy donor to supply excitation energy to the fluorescent material.

[0154] Furthermore, these mixed materials may form an excited complex. It is preferable to select a combination that forms an excited complex that exhibits emission overlapping with the wavelength of the lowest-energy absorption band of the luminescent material, as this facilitates smooth energy transfer and efficiently obtains light emission. This configuration is also preferable because it reduces the driving voltage.

[0155] Furthermore, at least one of the materials forming the excitation complex may be a phosphorescent material. By doing so, the triplet excitation energy can be efficiently converted to singlet excitation energy through reverse intersystem crossing.

[0156] For efficient excitation complex formation, it is preferable that the HOMO level of the hole-transporting material is above the HOMO level of the electron-transporting material. Furthermore, it is preferable that the LUMO level of the hole-transporting material is above the LUMO level of the electron-transporting material. The LUMO and HOMO levels of the materials can be derived from the electrochemical properties (reduction potential and oxidation potential) of the materials measured by cyclic voltammetry (CV).

[0157] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above can be replaced with transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0158] The electron transport layer 114 is a layer containing an electron-transporting material. As the electron-transporting material, any of the electron-transporting materials listed above as usable in the host material can be used.

[0159] Furthermore, the electron transport layer 114 has an electron mobility of 1 × 10⁻¹⁴ at an electric field strength [V / cm] square root of 600. -7 cm 2 / Vs or more 5×10 -5 cm2 It is preferable that the value is less than or equal to / Vs. By reducing the electron transport properties in the electron transport layer 114, the amount of electrons injected into the light-emitting layer can be controlled, preventing the light-emitting layer from becoming electron-excessive. Furthermore, it is preferable that the electron transport layer 114 contains an electron-transporting material and an alkali metal or alkaline earth metal element, compound, or complex. These configurations are particularly preferable because they result in a good lifetime when the hole injection layer is formed as a composite material and the HOMO level of the hole-transporting material in the composite material is a relatively deep HOMO level between -5.7eV and -5.4eV. In this case, it is preferable that the HOMO level of the electron-transporting material is -6.0eV or higher. Furthermore, it is preferable that the electron-transporting material is an organic compound having an anthracene skeleton, and more preferably an organic compound containing both an anthracene skeleton and a heterocyclic skeleton. The heterocyclic skeleton is preferably a nitrogen-containing five-membered ring skeleton or a nitrogen-containing six-membered ring skeleton. These heterocyclic skeletons are particularly preferably nitrogen-containing five-membered ring skeletons or nitrogen-containing six-membered ring skeletons that include two heteroatoms in the ring, such as pyrazole rings, imidazole rings, oxazole rings, thiazole rings, pyrazine rings, pyrimidine rings, and pyridazine rings. Furthermore, the alkali metal or alkaline earth metal element, compound, or complex preferably contains an 8-hydroxyquinolinate structure. Specifically, examples include 8-hydroxyquinolinate-lithium (abbreviated as Liq) and 8-hydroxyquinolinate-sodium (abbreviated as Naq). In particular, complexes of monovalent metal ions, especially lithium complexes, are preferred, with Liq being more preferred. When an 8-hydroxyquinolinate structure is included, its methyl-substituted derivatives (e.g., 2-methyl-substituted derivatives or 5-methyl-substituted derivatives) can also be used. Furthermore, it is preferable that within the electron transport layer, there is a concentration difference (including cases where it is zero) of alkali metals or alkaline earth metals in elemental form, compound, or complex form along the thickness direction.

[0160] Between the electron transport layer 114 and the second electrode 102, an electron injection layer 115 may be provided, containing an alkali metal or alkaline earth metal or a compound thereof, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), or 8-hydroxyquinolinatolithium (abbreviated as Liq). The electron injection layer 115 may be an electron transport layer containing an alkali metal or alkaline earth metal or a compound thereof, or an electride. Examples of electrides include a substance obtained by adding electrons to a mixed oxide of calcium and aluminum at a high concentration.

[0161] Furthermore, as the electron injection layer 115, it is also possible to use a layer containing an electron-transporting substance (preferably an organic compound having a bipyridine skeleton) with an alkali metal or alkaline earth metal fluoride at a concentration above that which results in a microcrystalline state (50 wt% or more). Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0162] Alternatively, a charge generation layer 116 may be provided instead of the electron injection layer 115 (Figure 1B). The charge generation layer 116 is a layer that can inject holes into the layer in contact with the cathode side and electrons into the layer in contact with the anode side by applying a potential. The charge generation layer 116 includes at least a P-type layer 117. The P-type layer 117 is preferably formed using a composite material listed above as a material that can constitute the hole injection layer 111. The P-type layer 117 may also be formed by laminating a film containing the acceptor material and a film containing the hole transport material as materials that constitute the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the second electrode 102, which is the cathode, and the light-emitting device operates. Furthermore, since the organic compound in one aspect of the present invention is an organic compound with a low refractive index, by using it in the P-type layer 117, a light-emitting device with good external quantum efficiency can be obtained.

[0163] Furthermore, it is preferable that the charge generation layer 116 includes, in addition to the P-type layer 117, one or both of the electron relay layer 118 and the electron injection buffer layer 119.

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

[0165] The electron injection buffer layer 119 can use materials with high electron injection capabilities, such as alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate or cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)).

[0166] Furthermore, if the electron injection buffer layer 119 is formed by including an electron-transporting substance and a donor substance, the donor substance can include alkali metals, alkaline earth metals, rare earth metals, and compounds thereof (alkali metal compounds (including oxides such as lithium oxide, halides, and carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, and carbonates), or rare earth metal compounds (including oxides, halides, and carbonates)), as well as organic compounds such as tetrathianaphthalene (abbreviated as TTN), nickerosene, and decamethylnickerosene. The electron-transporting substance can be formed using the same materials as those used to constitute the electron transport layer 114 described earlier.

[0167] As the material forming the second electrode 102, metals, alloys, electrically conductive compounds, and mixtures thereof with a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals represented by lithium (Li) and cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table represented by magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these (MgAg, AlLi), rare earth metals represented by europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, silicon, or indium oxide-tin oxide containing silicon oxide can be used as the second electrode 102, regardless of the magnitude of the work function. These conductive materials can be deposited using dry methods such as vacuum deposition or sputtering, inkjet methods, or spin coating methods. Alternatively, the material may be formed using a wet process with a sol-gel method, or it may be formed using a wet process with a paste of a metallic material.

[0168] Furthermore, various methods can be used to form the EL layer 103, regardless of whether they are dry or wet methods. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating may be used.

[0169] Furthermore, each electrode or layer described above may be formed using different film deposition methods.

[0170] The configuration of the layer provided between the first electrode 101 and the second electrode 102 is not limited to those described above. However, a configuration is preferred in which a light-emitting region is provided at a location away from the first electrode 101 and the second electrode 102 where holes and electrons recombine, in order to suppress quenching that occurs when the light-emitting region is in close proximity to the electrode or the metal used in the carrier injection layer.

[0171] Furthermore, the hole transport layer or electron transport layer in contact with the light-emitting layer 113, and especially the carrier transport layer near the recombination region in the light-emitting layer 113, is preferably made of a material whose band gap is larger than that of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer, in order to suppress energy transfer from excitons generated in the light-emitting layer.

[0172] Next, an embodiment of a light-emitting device (also called a stacked element or tandem element) with a configuration in which multiple light-emitting units are stacked will be described with reference to Figure 1C. This light-emitting device has multiple light-emitting units between the anode and the cathode. Each light-emitting unit has a configuration substantially similar to the EL layer 103 shown in Figure 1A. In other words, the light-emitting device shown in Figure 1C is a light-emitting device having multiple light-emitting units, while the light-emitting device shown in Figure 1A or Figure 1B is a light-emitting device having one light-emitting unit. Note that the organic compound described in Embodiment 1 only needs to be included in at least one of the multiple light-emitting units.

[0173] In Figure 1C, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between the anode 501 and the cathode 502, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 correspond to the first electrode 101 and the second electrode 102 in Figure 1A, respectively, and the same components described in the explanation of Figure 1A can be applied. Furthermore, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same configuration or different configurations.

[0174] The charge generation layer 513 has the function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied to the anode 501 and cathode 502. That is, in Figure 1C, when a voltage is applied such that the potential of the anode is higher than the potential of the cathode, the charge generation layer 513 only needs to inject electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512.

[0175] The charge generation layer 513 is preferably formed with the same configuration as the charge generation layer 116 described in Figure 1B. The composite material of organic compound and metal oxide has excellent carrier implantation and carrier transport properties, enabling low-voltage and low-current operation. If the anode side of the light-emitting unit is in contact with the charge generation layer 513, the charge generation layer 513 can also act as a hole injection layer for the light-emitting unit, so the light-emitting unit does not need to have a hole injection layer.

[0176] Furthermore, when an electron injection buffer layer 119 is provided in the charge generation layer 513, the electron injection buffer layer 119 plays the role of an electron injection layer in the anode-side light-emitting unit, so it is not necessarily required to form an electron injection layer in the anode-side light-emitting unit.

[0177] Figure 1C illustrates a light-emitting device having two light-emitting units, but the same principles can be applied to light-emitting devices with three or more stacked light-emitting units. As in the light-emitting device according to this embodiment, by arranging multiple light-emitting units separated between a pair of electrodes by a charge generation layer 513, it is possible to achieve high-brightness light emission while maintaining a low current density, and to realize a device with a long lifespan. Furthermore, it is possible to realize a light-emitting device that can be driven at a low voltage and consumes low power.

[0178] Furthermore, by making the light-emitting colors of each light-emitting unit different, it is possible to obtain a desired color of light emission from the entire light-emitting device. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green light-emitting colors from the first light-emitting unit and blue light-emitting color from the second light-emitting unit.

[0179] Furthermore, each layer or electrode, such as the EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer, can be formed using methods such as vapor deposition (including vacuum deposition), droplet ejection (also known as inkjet printing), coating, and gravure printing. They may also contain low-molecular-weight materials, medium-molecular-weight materials (including oligomers and dendrimers), or polymer materials.

[0180] (Embodiment 3) This embodiment describes a light-emitting device using the light-emitting device described in Embodiment 2.

[0181] In this embodiment, a light-emitting device fabricated using the light-emitting device described in Embodiment 2 will be explained with reference to Figure 2. Figure 2A is a top view showing the light-emitting device, and Figure 2B is a cross-sectional view obtained by cutting Figure 2A along AB and CD. This light-emitting device includes a drive circuit section (source line drive circuit) 601, a pixel section 602, and a drive circuit section (gate line drive circuit) 603, all indicated by dotted lines, to control the light emission of the light-emitting device. Furthermore, 604 is a sealing substrate, and 605 is a sealing material, with the area enclosed by the sealing material 605 being a space 607.

[0182] The routing wiring 608 is for transmitting signals input to the source line drive circuit 601 and the gate line drive circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from the FPC (flexible printed circuit) 609, which serves as an external input terminal. Although only the FPC is shown in this illustration, a printed circuit board (PWB) may be attached to this FPC. In this specification, the light-emitting device includes not only the light-emitting device itself, but also the state in which the FPC or PWB is attached to it.

[0183] Next, the cross-sectional structure will be explained using Figure 2B. A drive circuit section and a pixel section are formed on the element substrate 610, and here, the source line drive circuit 601, which is the drive circuit section, and one pixel in the pixel section 602 are shown.

[0184] The element substrate 610 may be made using a substrate made of glass, quartz, organic resin, metal, alloy, or semiconductor, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, or acrylic resin.

[0185] The structure of the transistor used in the pixel or driving circuit is not particularly limited. For example, it may be an inverse staggered transistor or a staggered transistor. It may also be a top-gate or bottom-gate transistor. The semiconductor material used for the transistor is not particularly limited; for example, silicon, germanium, silicon carbide, gallium nitride, etc., can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn metal oxide, may be used.

[0186] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors having a crystalline region in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0187] Here, it is preferable to use oxide semiconductors for semiconductor devices such as transistors used in the pixels or driving circuits described above, as well as transistors used in touch sensors and the like, which will be discussed later. In particular, it is preferable to use oxide semiconductors with a wider bandgap than silicon. By using oxide semiconductors with a wider bandgap than silicon, the current in the off state of the transistor can be reduced.

[0188] The above oxide semiconductor preferably contains at least indium (In) or zinc (Zn). More preferably, it is an oxide semiconductor containing an oxide represented as an In-M-Zn oxide (where M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0189] In particular, it is preferable to use an oxide semiconductor film as the semiconductor layer, which has multiple crystalline portions, the c-axis of which is oriented perpendicular to the surface on which the semiconductor layer is formed or to the upper surface of the semiconductor layer, and which does not have grain boundaries between adjacent crystalline portions.

[0190] By using such a material as the semiconductor layer, fluctuations in electrical characteristics can be suppressed, and a highly reliable transistor can be realized.

[0191] In addition, due to its low off-current, the transistor having the above-described semiconductor layer can hold the charges accumulated in the capacitor via the transistor for a long period of time. By applying such a transistor to pixels, it becomes possible to stop the drive circuit while maintaining the gradation of the image displayed in each display area. As a result, an electronic device with extremely low power consumption can be realized.

[0192] For stabilizing the characteristics of the transistor, it is preferable to provide an underlayer film. As the underlayer film, an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, and a silicon nitride oxide film can be used, and it can be formed as a single layer or by lamination. The underlayer film can be formed using a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, and a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, etc. Note that the underlayer film may not be provided if not necessary.

[0193] Note that FET623 indicates one of the transistors formed in the drive circuit section 601. Also, the drive circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In the present embodiment, a driver integrated type in which the drive circuit is formed on the substrate is shown, but this is not necessarily required, and the drive circuit can also be formed outside the substrate instead of on the substrate.

[0194] Also, the pixel section 602 is formed of a plurality of pixels including a switching FET611, a current control FET612, and a first electrode 613 electrically connected to its drain, but is not limited thereto, and a pixel section combining three or more FETs and a capacitive element may be used.

[0195] An insulator 614 is formed to cover the end portion of the first electrode 613. Here, it can be formed by using a positive photosensitive acrylic resin film.

[0196] Also, in order to make the covering property of the EL layer and the like formed later good, a curved surface having a curvature is formed at the upper end portion or the lower end portion of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material of the insulator 614, it is preferable to provide a curved surface having a radius of curvature (0.2 μm to 3 μm) only at the upper end portion of the insulator 614. Also, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0197] An EL layer 616 and a second electrode 617 are respectively formed on the first electrode 613. Here, as the material used for the first electrode 613 that functions as an anode, it is desirable to use a material having a large work function. For example, in addition to single-layer films such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, and a Pt film, a laminate of a titanium nitride film and a film mainly composed of aluminum, a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film can be used. Note that when a laminated structure is used, the resistance as a wiring is low, good ohmic contact can be achieved, and it can further function as an anode.

[0198] Also, the EL layer 616 is formed by various methods typified by a vapor deposition method using a vapor deposition mask, an inkjet method, and a spin coating method. The EL layer 616 includes the configuration as described in Embodiment 2. Also, as other materials constituting the EL layer 616, a low molecular compound or a high molecular compound (including an oligomer and a dendrimer) may be used.

[0199] Furthermore, it is preferable to use a material with a small work function (such as Al, Mg, Li, Ca, or alloys or compounds thereof (MgAg, MgIn, AlLi, etc.)) for the second electrode 617, which is formed on the EL layer 616 and functions as a cathode. When light generated in the EL layer 616 is transmitted through the second electrode 617, it is preferable to use a laminate of a thin metal film and a transparent conductive film (such as ITO, indium oxide containing 2-20 wt% zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) as the second electrode 617.

[0200] The first electrode 613, the EL layer 616, and the second electrode 617 form a light-emitting device. This light-emitting device is the light-emitting device described in Embodiment 2. Although the pixel portion is made up of multiple light-emitting devices, the light-emitting device in this embodiment may contain a mixture of the light-emitting device described in Embodiment 2 and light-emitting devices having other configurations.

[0201] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, the light-emitting device 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The space 607 is filled with a filler material, which may be an inert gas (nitrogen, argon, etc.) or a sealing material. A recess is formed in the sealing substrate, and a desiccant is placed therein to suppress deterioration due to the effects of moisture, which is a preferred configuration.

[0202] Furthermore, it is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as impermeable to moisture and oxygen as possible. In addition to glass substrates and quartz substrates, plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, or acrylic resin can be used as the material for the sealing substrate 604.

[0203] Although not shown in Figure 2, a protective film may be provided on the second electrode. The protective film may be formed of an organic resin film or an inorganic insulating film. Alternatively, the protective film may be formed to cover the exposed portion of the sealing material 605. Furthermore, the protective film can be provided to cover the surface and sides of the pair of substrates, the sealing layer, and the exposed sides of the insulating layer.

[0204] The protective film can be made of a material that is impermeable to impurities such as water. Therefore, the diffusion of the above-mentioned impurities from the outside to the inside can be effectively suppressed.

[0205] Materials that constitute the protective film can include oxides, nitrides, fluorides, sulfides, ternary compounds, metals, or polymers. For example, materials containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, or indium oxide can be used. Materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride can be used. Nitrides containing titanium and aluminum, oxides containing titanium and aluminum, oxides containing aluminum and zinc, sulfides containing manganese and zinc, sulfides containing cerium and strontium, oxides containing erbium and aluminum, oxides containing yttrium and zirconium can be used.

[0206] It is preferable to form the protective film using a film deposition method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks or pinholes, or a protective film with a uniform thickness. Furthermore, it is possible to reduce the damage inflicted on the processed workpiece when forming the protective film.

[0207] For example, by forming a protective film using the ALD method, a uniform protective film with few defects can be formed on surfaces with complex uneven shapes, including the top, sides, and back surfaces of touch panels.

[0208] As described above, a light-emitting device can be obtained using the light-emitting device described in Embodiment 2.

[0209] Since the light-emitting device in this embodiment uses the light-emitting device described in Embodiment 2, a light-emitting device with good characteristics can be obtained. Specifically, because the light-emitting device described in Embodiment 2 has good luminous efficiency, it is possible to make a light-emitting device with low power consumption.

[0210] Figure 3 shows an example of a light-emitting device that is made full-color by forming a light-emitting device that emits white light and providing a colored layer (color filter), etc. Figure 3A shows the substrate 1001, the underlayer 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 part 1042, the pixel part 1040, the drive circuit part 1041, the first electrodes 1024W, 1024R, 1024G, 1024B of the light-emitting device, the partition wall 1025, the EL layer 1028, the second electrode 1029 of the light-emitting device, the sealing substrate 1031, and the sealing material 1032, etc.

[0211] In Figure 3A, the colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) are provided on a transparent substrate 1033. A black matrix 1035 may also be provided. The transparent substrate 1033 on which the colored layers and black matrix are provided is aligned and fixed to the substrate 1001. The colored layers and black matrix 1035 are covered with an overcoat layer 1036. In Figure 3A, there is an emissive layer that emits light to the outside without passing through the colored layers, and an emissive layer that emits light to the outside by passing through each colored layer. Light that does not pass through the colored layers is white, and light that passes through the colored layers is red, green, and blue, so an image can be represented with four colored pixels.

[0212] Figure 3B shows an example in which colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. Thus, the colored layers may also be provided between the substrate 1001 and the encapsulating substrate 1031.

[0213] Furthermore, although the light-emitting device described above is a bottom-emission type device that extracts light from the substrate 1001 on which the FET is formed, it may also be a top-emission type device that extracts light from the sealing substrate 1031. A cross-sectional view of the top-emission type light-emitting device is shown in Figure 4. In this case, the substrate 1001 can be a substrate that does not transmit light. The process is the same as for the bottom-emission type light-emitting device until the electrode 1022 connecting the FET and the anode of the light-emitting device is fabricated. After that, a third interlayer insulating film 1037 is formed covering the electrode 1022. This insulating film may also play a planarization role. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film, as well as other known materials.

[0214] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are anodes here, but they can also be cathodes. Also, in the case of a top-emission type light-emitting device as shown in FIG. 4, it is preferable that the first electrode be a reflective electrode. The structure of the EL layer 1028 shall be the same as the structure described as the EL layer 103 in Embodiment 2, and the element structure shall be such that white light emission can be obtained.

[0215] In a top-emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with color filter layers (red color filter layer 1034R, green color filter layer 1034G, blue color filter layer 1034B). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The color filter layers (red color filter layer 1034R, green color filter layer 1034G, blue color filter layer 1034B) and the black matrix may be covered by an overcoat layer 1036. Note that the sealing substrate 1031 shall use a substrate having translucency. Also, although an example of full-color display using four colors of red, green, blue, and white is shown here, it is not particularly limited, and full-color display may be performed using four colors of red, yellow, green, and blue or three colors of red, green, and blue.

[0216] In a top-emission type light-emitting device, application of a microcavity structure can be suitably performed. A light-emitting device having a microcavity structure can be obtained by making the first electrode a reflective electrode and the second electrode a semi-transmissive and semi-reflective electrode. Between the reflective electrode and the semi-transmissive and semi-reflective electrode, there is at least an EL layer and at least a light-emitting layer serving as a light-emitting region.

[0217] Note that the reflective electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100%, and its resistivity is 1×10 -2 Ωcm or less for the film. Also, the semi-transmissive and semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and its resistivity is 1×10 -2 Ωcm or less for the film.

[0218] The light emitted from the light-emitting layer contained in the EL layer is reflected by the reflective electrode and the semi-transparent / semi-reflective electrode, causing resonance.

[0219] This light-emitting device allows for changing the optical distance between the reflective electrode and the semi-transparent / semi-reflective electrode by varying the thickness of the transparent conductive film, the aforementioned composite material, and the carrier transport material. This makes it possible to enhance light of resonant wavelengths and attenuate light of non-resonant wavelengths between the reflective electrode and the semi-transparent / semi-reflective electrode.

[0220] Furthermore, since the light reflected back by the reflective electrode (first reflected light) interferes significantly with the light that directly enters the semi-transparent / semi-reflective electrode from the light-emitting layer (first incident light), it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number greater than or equal to 1, and λ is the wavelength of the light emission to be amplified). By adjusting this optical distance, the phases of the first reflected light and the first incident light can be aligned, and the light emission from the light-emitting layer can be further amplified.

[0221] In the above configuration, the EL layer may have a structure with multiple light-emitting layers or a structure with a single light-emitting layer. For example, it may be applied to a configuration in which multiple EL layers are provided in a single light-emitting device with a charge generation layer in between, and one or more light-emitting layers are formed in each EL layer, in combination with the tandem light-emitting device configuration described above.

[0222] By incorporating a microcavity structure, it becomes possible to enhance the emission intensity in the front direction at specific wavelengths, thereby reducing power consumption. Furthermore, in the case of a light-emitting device that displays images using four sub-pixels of red, yellow, green, and blue, in addition to the brightness enhancement effect of yellow emission, a microcavity structure tailored to the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with excellent characteristics.

[0223] Since the light-emitting device in this embodiment uses the light-emitting device described in Embodiment 2, a light-emitting device with good characteristics can be obtained. Specifically, because the light-emitting device described in Embodiment 2 has good luminous efficiency, it is possible to make a light-emitting device with low power consumption.

[0224] Up to this point, we have described an active matrix type light-emitting device, but from here on we will describe a passive matrix type light-emitting device. Figure 5 shows a passive matrix type light-emitting device manufactured by applying the present invention. Figure 5A is a perspective view of the light-emitting device, and Figure 5B is a cross-sectional view of Figure 5A cut along the X and Y lines. In Figure 5, an EL layer 955 is provided on the substrate 951 between electrodes 952 and 956. The ends of electrodes 952 are covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 have a slope such that the distance between one side wall and the other side wall narrows as they get closer to the substrate surface. In other words, the cross-section of the partition layer 954 in the short-side direction is trapezoidal, with the bottom side (facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) being shorter than the top side (facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent malfunctions of the light-emitting device caused by static electricity, etc. Furthermore, even in a passive matrix type light-emitting device, the light-emitting device described in Embodiment 2 is used, resulting in a light-emitting device with good reliability or low power consumption.

[0225] As described above, the light-emitting device is suitable for use as a display device for representing images because it is possible to control each of the numerous minute light-emitting devices arranged in a matrix.

[0226] Furthermore, this embodiment can be freely combined with other embodiments.

[0227] (Embodiment 4) In this embodiment, an example of using the light-emitting device described in Embodiment 2 as an illumination device will be explained with reference to Figure 6. Figure 6B is a top view of the illumination device, and Figure 6A is a cross-sectional view of ef in Figure 6B.

[0228] In this embodiment, the lighting device has a first electrode 401 formed on a translucent substrate 400 which serves as a support. The first electrode 401 corresponds to the first electrode 101 in Embodiment 2. When light is extracted from the first electrode 401 side, the first electrode 401 is formed from a translucent material.

[0229] A pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0230] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 2, or the combined configuration of the light-emitting units 511, 512 and the charge generation layer 513. Please refer to the relevant description for details on these configurations.

[0231] A second electrode 404 is formed by covering the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in Embodiment 2. When light emission is extracted from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. Voltage is supplied to the second electrode 404 by connecting it to the pad 412.

[0232] As described above, the lighting device shown in this embodiment has a light-emitting device having a first electrode 401, an EL layer 403, and a second electrode 404. Since this light-emitting device is a light-emitting device with high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption.

[0233] The lighting device is completed by fixing and sealing the substrate 400, on which the light-emitting device having the above configuration is formed, and the sealing substrate 407 using sealing materials 405 and 406. Either sealing material 405 or 406 may be used. In addition, a desiccant can be mixed into the inner sealing material 406 (not shown in Figure 6B), which allows for the adsorption of moisture and leads to improved reliability.

[0234] Furthermore, by extending the pad 412 and a portion of the first electrode 401 outside the sealing materials 405 and 406, it can be used as an external input terminal. Alternatively, an IC chip 420 with a converter or the like mounted on it may be provided on top of it.

[0235] As described above, the lighting device described in this embodiment uses the light-emitting device described in Embodiment 2 as the EL element, and can be a lighting device with low power consumption.

[0236] (Embodiment 5) This embodiment describes an example of an electronic device that includes the light-emitting device described in Embodiment 2 as part of it. The light-emitting device described in Embodiment 2 has good luminous efficiency and low power consumption. As a result, the electronic device described in this embodiment can be an electronic device having a light-emitting section with low power consumption.

[0237] Examples of electronic devices to which the above-mentioned light-emitting devices are applied include television equipment (also called televisions or television receivers), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, personal digital assistants, sound playback devices, and large game machines such as pachinko machines. Specific examples of these electronic devices are shown below.

[0238] Figure 7A shows an example of a television system. The television system has a display unit 7103 incorporated into a housing 7101. This figure also shows a configuration in which the housing 7101 is supported by a stand 7105. The display unit 7103 is capable of displaying images, and the display unit 7103 is configured by arranging the light-emitting devices described in Embodiment 2 in a matrix.

[0239] The television system can be operated using the operation switches on the housing 7101 and a separate remote control unit 7110. The operation keys 7109 on the remote control unit 7110 allow for channel and volume control, and the image displayed on the display unit 7103 can be controlled. Alternatively, the remote control unit 7110 may be configured to include a display unit 7107 that displays information output from the remote control unit 7110.

[0240] The television system will consist of a receiver and a modem. The receiver will be able to receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it will also be possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0241] Figure 7B1 shows a computer, which includes a main unit 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer is manufactured by arranging the light-emitting devices described in Embodiment 2 in a matrix and using them for the display unit 7203. The computer in Figure 7B1 may also take the form shown in Figure 7B2. The computer in Figure 7B2 has a second display unit 7210 instead of the keyboard 7204 and pointing device 7206. The second display unit 7210 is a touch panel, and input can be performed by operating the input display shown on the second display unit 7210 with a finger or a dedicated pen. In addition to the input display, the second display unit 7210 can also display other images. The display unit 7203 may also be a touch panel. Because the two screens are connected by a hinge, it is possible to prevent problems such as scratching or damaging the screens when storing or transporting the device.

[0242] Figure 7C shows an example of a mobile terminal. The mobile phone includes a display unit 7402 built into the housing 7401, as well as operation buttons 7403, an external connection port 7404, a speaker 7405, and a microphone 7406. The mobile phone has a display unit 7402 made by arranging the light-emitting devices described in Embodiment 2 in a matrix.

[0243] The mobile terminal shown in Figure 7C can also be configured to allow information input by touching the display unit 7402 with a finger or stylus. In this case, operations such as making a phone call or composing an email can be performed by touching the display unit 7402 with a finger or stylus.

[0244] The display unit 7402 has three main modes. The first is a display mode that primarily displays images, the second is an input mode that primarily inputs information represented by text, and the third is a display + input mode that combines the display mode and the input mode.

[0245] For example, when making a phone call or composing an email, the display unit 7402 should be set to a text input mode, which primarily focuses on text input, and the user should perform the text input operation displayed on the screen. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402.

[0246] Furthermore, by providing a detection device inside the mobile terminal that has a sensor for detecting tilt, such as a gyroscope or accelerometer, it is possible to determine the orientation of the mobile terminal (portrait or landscape) and automatically switch the screen display of the display unit 7402.

[0247] Furthermore, the screen mode can be switched by touching the display unit 7402 or by operating the operation button 7403 on the housing 7401. It is also possible to switch modes depending on the type of image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it can be switched to display mode; if it is text data, it can be switched to input mode.

[0248] Furthermore, in input mode, the system may detect a signal detected by the optical sensor of the display unit 7402 and, if there is no input via touch operation on the display unit 7402 for a certain period of time, control may be made to switch the screen mode from input mode to display mode.

[0249] The display unit 7402 can also function as an image sensor. For example, by touching the display unit 7402 with the palm or finger, the user can be authenticated by capturing images of palm prints, fingerprints, etc. Furthermore, by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light in the display unit, it is also possible to capture images of finger veins or palmar veins.

[0250] Figure 8A is a schematic diagram showing an example of a cleaning robot.

[0251] The cleaning robot 5100 has a display 5101 on its top surface, multiple cameras 5102 on its sides, a brush 5103, and control buttons 5104. Although not shown in the illustration, the cleaning robot 5100 also has wheels, a suction port, etc. on its underside. The cleaning robot 5100 is also equipped with various sensors such as an infrared sensor, an ultrasonic sensor, an accelerometer, a piezoelectric sensor, a light sensor, or a gyroscope. The cleaning robot 5100 is also equipped with a means of wireless communication.

[0252] The cleaning robot 5100 is self-propelled, can detect dirt 5120, and can suck up the dirt through a suction port located on its underside.

[0253] Furthermore, the cleaning robot 5100 can analyze images captured by the camera 5102 to determine the presence or absence of obstacles such as walls, furniture, or steps. If the image analysis detects objects that could become entangled in the brush 5103, such as wiring, it can stop the brush 5103 from rotating.

[0254] The display 5101 can display information such as the remaining battery level or the amount of dirt collected. The path taken by the cleaning robot 5100 may also be displayed on the display 5101. Alternatively, the display 5101 may be a touch panel, and operation buttons 5104 may be provided on the display 5101.

[0255] The cleaning robot 5100 can communicate with the portable electronic device 5140. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can check the status of the room even when they are away from home. In addition, the display on the display 5101 can be viewed on the portable electronic device 5140.

[0256] A light-emitting device according to one aspect of the present invention can be used in a display 5101.

[0257] The robot 2100 shown in Figure 8B includes a computing 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 movement mechanism 2108.

[0258] The microphone 2102 has the function of detecting the user's voice and ambient sounds. The speaker 2104 has the function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and speaker 2104.

[0259] The display 2105 has the function of displaying various types of 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 also be a detachable information terminal, and by installing it in a fixed position on the robot 2100, charging and data transfer can be made possible.

[0260] The upper camera 2103 and the lower camera 2106 have the function of imaging the area around the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of obstacles in the direction of travel when the robot 2100 moves forward using the movement mechanism 2108. The robot 2100 can recognize its surrounding environment and move safely using the upper camera 2103, the lower camera 2106 and the obstacle sensor 2107. The light-emitting device according to one aspect of the present invention can be used in the display 2105.

[0261] Figure 8C shows an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, a connection terminal 5006, a sensor 5007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 5008, a display unit 5002, a support unit 5012, an earphone 5013, etc.

[0262] A light-emitting device according to one aspect of the present invention can be used in the display unit 5001 and the display unit 5002.

[0263] Figure 9 shows an example in which the light-emitting device described in Embodiment 2 is used in a desk lamp, which is a lighting device. The desk lamp shown in Figure 9 has a housing 2001 and a light source 2002, and the lighting device described in Embodiment 3 may be used as the light source 2002.

[0264] Figure 10 shows an example of using the light-emitting device described in Embodiment 2 as an indoor lighting device 3001. Since the light-emitting device described in Embodiment 2 is a light-emitting device with high luminous efficiency, it can be used as a lighting device with low power consumption. Furthermore, since the light-emitting device described in Embodiment 2 can be made to cover a large area, it can be used as a large-area lighting device. In addition, since the light-emitting device described in Embodiment 2 is thin, it can be used as a thin lighting device.

[0265] The light-emitting device described in Embodiment 2 can also be mounted on the windshield or dashboard of an automobile. Figure 11 shows one embodiment in which the light-emitting device described in Embodiment 2 is used on the windshield or dashboard of an automobile. Display areas 5200 to 5203 are display areas provided using the light-emitting device described in Embodiment 2.

[0266] Display area 5200 and display area 5201 are display devices equipped with the light-emitting device described in Embodiment 2, which is installed on the windshield of an automobile. The light-emitting device described in Embodiment 2 can be made into a so-called see-through display device, where the opposite side is visible, by making the first electrode and the second electrode from translucent electrodes. If the display is in a see-through state, it can be installed on the windshield of an automobile without obstructing the view. When a transistor is provided for driving, it is preferable to use a translucent transistor, such as an organic transistor made of organic semiconductor material or a transistor using oxide semiconductor material.

[0267] The display area 5202 is a display device equipped with the light-emitting device described in Embodiment 2, which is provided on the pillar. By displaying images from an imaging means provided on the vehicle body on the display area 5202, the field of view obstructed by the pillar can be compensated for. Similarly, the display area 5203 provided on the dashboard can compensate for the field of view obstructed by the vehicle body by displaying images from an imaging means provided on the outside of the vehicle, thereby compensating for blind spots and enhancing safety. By displaying images in a way that compensates for the parts that are not visible, safety checks can be performed more naturally and without discomfort.

[0268] Display area 5203 can also provide various information such as navigation information, speed, RPM, mileage, fuel level, gear status, or air conditioning settings. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in display areas 5200 to 5202. Furthermore, display areas 5200 to 5203 can also be used as illumination devices.

[0269] Figures 12A and 12B also show a foldable portable information terminal 5150. The foldable portable information terminal 5150 has a housing 5151, a display area 5152, and a bending section 5153. Figure 12A shows the portable information terminal 5150 in its unfolded state. Figure 12B shows the portable information terminal in its folded state. Despite having a large display area 5152, the portable information terminal 5150 is compact and highly portable when folded.

[0270] The display area 5152 can be folded in half by the bending portion 5153. The bending portion 5153 is composed of an expandable member and a plurality of support members. When folded, the expandable member extends, and the bending portion 5153 folds to have a radius of curvature of 2 mm or more, preferably 3 mm or more.

[0271] The display area 5152 may also be a touch panel (input / output device) equipped with a touch sensor (input device). A light-emitting device according to one aspect of the present invention can be used in the display area 5152.

[0272] Figures 13A to 13C also show the foldable portable information terminal 9310. Figure 13A shows the portable information terminal 9310 in its unfolded state. Figure 13B shows the portable information terminal 9310 in an intermediate state, either unfolded or folded. Figure 13C shows the portable information terminal 9310 in its folded state. The portable information terminal 9310 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state.

[0273] The display panel 9311 is supported by three housings 9315 connected by a hinge 9313. The display panel 9311 may also be a touch panel (input / output device) equipped with a touch sensor (input device). Furthermore, the display panel 9311 can be reversibly transformed from an unfolded state to a folded state by bending the two housings 9315 via the hinge 9313. A light-emitting device according to one aspect of the present invention can be used in the display panel 9311.

[0274] Furthermore, the configuration shown in this embodiment can be used by appropriately combining the configurations shown in Embodiments 1 to 4.

[0275] Furthermore, a compound according to one embodiment of the present invention can be used in photoelectric conversion elements such as organic thin-film solar cells (OPVs) or organic photodiodes (OPDs). More specifically, because it has carrier transport properties, it can be used in carrier transport layers and carrier implantation layers. In addition, by using a mixed film with a donor substance, it can be used as a charge generation layer. Furthermore, because it is photoexcitable, it can be used as a power generation layer or an active layer.

[0276] As described above, the application range of the light-emitting device equipped with the light-emitting device described in Embodiment 2 is extremely broad, and this light-emitting device can be applied to electronic devices in all fields. By using the light-emitting device described in Embodiment 2, it is possible to obtain electronic devices with low power consumption. [Examples]

[0277] <<Synthesis Example 1>> This synthesis example specifically describes the synthesis method for 3-[4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviated as DBTPIPt-II), which was shown as structural formula (100) in Embodiment 1. The structural formula of DBTPIPt-II is shown below.

[0278] [ka]

[0279] <Step 1: Synthesis of 3-[4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviation: DBTPIPt-II)> 0.80 g (2.7 mmol) of 3-bromoimidazo[1,2-f]phenanthridine, 1.2 g (4.0 mmol) of 4-(dibenzothiophen-4-yl)phenylboronic acid, 1.1 g (7.6 mmol) of potassium carbonate, 27 mL of toluene, 3 mL of ethanol, and 3 mL of water were added to a 200 mL three-necked flask. This mixture was degassed by stirring under reduced pressure, and the flask was purged with nitrogen. 0.12 g (0.10 mmol) of tetrakis(triphenylphosphine)palladium(0) was added to this mixture, and the mixture was stirred at 80°C for 6 hours under a nitrogen stream, and then refluxed at 100°C for 11 hours. After refluxing, water was added to the mixture, and the aqueous layer and organic layer were separated. The aqueous layer was extracted with toluene. The obtained extract and organic layer were washed together with saturated sodium bicarbonate aqueous solution and saturated brine, and the organic layer was dried over magnesium sulfate. This mixture was filtered by gravity, and the filtrate was concentrated to obtain an oily substance. The obtained oily substance was purified by alumina column chromatography (toluene:ethyl acetate = 50:1) to obtain an oily substance. Methanol was added to this oily substance, and sonication was irradiated. The precipitated solid was collected to obtain the target white powder in a yield of 1.0 g and 79%. 1.0 g of the obtained white powder was purified by sublimation using the train sublimation method under conditions of 3.2 Pa pressure, argon flow rate of 5.0 mL / min, and 260°C for 14 hours. After sublimation purification, 0.89 g of white solid was obtained with a recovery rate of 87%. The synthesis scheme for Step 1 is shown below.

[0280] [ka]

[0281] Nuclear magnetic resonance spectroscopy of the white solid obtained in step 1 above ( 1 The results of the analysis by 1H-NMR are shown below. 1 The 1H-NMR charts are shown in Figures 14A and 14B. From these, it can be seen that DBTPIPt-II, the organic compound of the present invention, was obtained in this synthesis example.

[0282] 1H NMR(CDCl3,300MHz):δ=7.33-7.38(m,1H),7.45-7.54(m,3H),7.58(s,1H),7.61-7.78(m,7H),7.86- 7.93(m,3H),8.19-8.26(m,2H),8.39-8.43(m,1H),8.50(dd,J=8.4Hz,1.5Hz,1H),8.74-8.78(m,1H).

[0283] Next, Figure 15 shows the absorption and emission spectra of a toluene solution of DBTPIPt-II. Figure 16 shows the absorption and emission spectra of the thin film. The solid thin film was fabricated on a quartz substrate by vacuum deposition. A UV-Vis spectrophotometer (JASCO Corporation, V550 model) was used to measure the absorption spectra. The absorption spectrum of the solution was obtained by subtracting the absorption spectrum measured with only the solvent in a quartz cell from the absorption spectrum measured with the DBTPIPt-II solution in a quartz cell. The absorption spectrum of the thin film was obtained by subtracting the absorption spectrum of the quartz substrate from the absorption spectrum of DBTPIPt-II deposited on the quartz substrate. A fluorometer (Hamamatsu Photonics Ltd., FS920 model) was used to measure the emission spectra.

[0284] Figure 15 shows that the toluene solution of DBTPIPt-II exhibited absorption peaks around 333 nm and 292 nm, with an emission wavelength peak at 415 nm (excitation wavelength 338 nm). Figure 16 shows that the thin film of DBTPIPt-II exhibited absorption peaks around 340 nm, 295 nm, and 242 nm, with emission wavelength peaks around 412 nm and 424 nm (excitation wavelength 340 nm). These results demonstrate that DBTPIPt-II, an organic compound according to one embodiment of the present invention, can be effectively used as a host transport material for luminescent materials and visible-range fluorescent materials.

[0285] Furthermore, it was found that the DBTPIPt-II thin film exhibits good film quality, being less prone to aggregation and showing minimal changes even under atmospheric conditions.

[0286] Next, the HOMO and LUMO levels of DBTPIPt-II were calculated based on cyclic voltammetry (CV) measurements. The calculation method is shown below.

[0287] The measuring instrument used was an electrochemical analyzer (manufactured by BAS Corporation, model number: ALS Model 600A or 600C). The solution used for CV measurement was prepared by dissolving anhydrous dimethylformamide (DMF) (manufactured by Aldrich Corporation, 99.8%, catalog number: 22705-6) as the solvent, tetra-n-butylammonium perchlorate (n-Bu4NClO4) (manufactured by Tokyo Chemical Industry Co., Ltd., catalog number: T0836) as the supporting electrolyte to a concentration of 100 mmol / L, and then dissolving the target substance to a concentration of 2 mmol / L. A platinum electrode (manufactured by BAS Corporation, PTE platinum electrode) was used as the working electrode, a platinum electrode (manufactured by BAS Corporation, VC-3 Pt counter electrode (5cm)) was used as the auxiliary electrode, and Ag / Ag was used as the reference electrode. + Electrodes (RE7 non-aqueous solvent reference electrode, manufactured by BAS Corporation) were used. Measurements were performed at room temperature (20 to 25°C). The scan speed during CV measurement was standardized to 0.1 V / sec, and the oxidation potential Ea [V] and reduction potential Ec [V] relative to the reference electrode were measured. Ea was defined as the intermediate potential of the oxidation-reduction wave, and Ec was defined as the intermediate potential of the reduction-oxidation wave. Here, since the potential energy of the reference electrode used in this example with respect to the vacuum level is known to be -4.94 [eV], the HOMO level [eV] = -4.94 - Ea and the LUMO level [eV] = -4.94 - Ec can be used to determine the HOMO level and LUMO level, respectively.

[0288] Furthermore, CV measurements were repeated 100 times, and the oxidation-reduction wave at the 100th cycle was compared with the oxidation-reduction wave at the 1st cycle to investigate the electrical stability of the compound.

[0289] Measurements of the oxidation potential Ea [V] revealed that the HOMO level of DBTPIPt-II is -5.89 eV. Furthermore, measurements of the reduction potential Ec [V] revealed that the LUMO level of DBTPIPt-II is -2.35 eV. Repeated measurements of the oxidation-reduction wave showed that DBTPIPt-II maintained a peak intensity of 89% in the Ea measurement, confirming its excellent resistance to oxidation. [Examples]

[0290] ≪Synthesis Example 2≫ This synthesis example specifically describes the synthesis method for 3-[4-(carbazole-9-yl)phenyl]imidazo[1,2-f]phenanthidine (abbreviated as CzPIPt), which was shown as structural formula (135) in Embodiment 1. The structural formula of CzPIPt is shown below.

[0291] [ka]

[0292] <Step 1: Synthesis of 3-[4-(carbazole-9-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviation: CzPIPt)> 0.80 g (2.7 mmol) of 3-bromoimidazo[1,2-f]phenanthridine, 1.3 g (4.4 mmol) of 4-(carbazole-9-yl)phenylboronic acid, 1.0 g (7.5 mmol) of potassium carbonate, 30 mL of toluene, 3 mL of ethanol, and 3 mL of water were added to a 200 mL three-necked flask. This mixture was degassed by stirring under reduced pressure, and the flask was purged with nitrogen. 0.17 g (0.15 mmol) of tetrakis(triphenylphosphine)palladium(0) was added to this mixture, and the mixture was stirred at 80°C for 9 hours under a nitrogen stream, followed by reflux at 100°C for 6 hours. After reflux, water was added to the mixture, and the aqueous layer and organic layer were separated. The aqueous layer was extracted with toluene. The obtained extract and organic layer were washed together with saturated sodium bicarbonate aqueous solution and saturated brine, and then dried over magnesium sulfate. This mixture was filtered by gravity, and the filtrate was concentrated to obtain a solid. The obtained solid was purified by silica gel column chromatography (toluene:ethyl acetate = 20:1) and alumina column chromatography (toluene:ethyl acetate = 50:1) to obtain a solid. This solid was recrystallized with toluene to obtain the target white powder in a yield of 0.86 g and 69%. 0.85 g of the obtained white powder was purified by sublimation using the train sublimation method under conditions of 3.0 Pa pressure, argon flow rate of 5.0 mL / min, and 260 °C for 16 hours. After sublimation purification, 0.77 g of white solid was obtained with a recovery rate of 91%. The synthesis scheme for Step 1 is shown below.

[0293] [ka]

[0294] Nuclear magnetic resonance spectroscopy of the white solid obtained in step 1 above ( 1 The results of the analysis by 1H-NMR are shown below. 1 The 1H-NMR charts are shown in Figures 17A and 17B. From this, it can be seen that CzPIPt, the organic compound of the present invention, was obtained in this synthesis example.

[0295] 1H NMR(CDCl3,300MHz):δ=7.32-7.41(m,3H),7.45-7.52(m,3H),7.57-7.61(m,3H),7.67-7.81(m, 7H), 8.19(d,J=7.8Hz,2H),8.40-8.44(m,1H),8.52(dd,J=8.4Hz,1.5Hz,1H),8.74-8.79(m,1H).

[0296] Next, the absorption and emission spectra of a toluene solution of CzPIPt are shown in Figure 18. The absorption and emission spectra of the thin film are also shown in Figure 19. The solid thin film was fabricated on a quartz substrate by vacuum deposition. A UV-Vis spectrophotometer (JASCO Corporation, V550) was used to measure the absorption spectra. The absorption spectrum of the solution was obtained by subtracting the absorption spectrum of the CzPIPt solution (measured in a quartz cell) from the absorption spectrum of the CzPIPt solution (measured in a quartz cell). The absorption spectrum of the thin film was obtained by subtracting the absorption spectrum of the quartz substrate from the absorption spectrum of the CzPIPt film deposited on the quartz substrate. A fluorometer (Hamamatsu Photonics Ltd., FS920) was used to measure the emission spectra.

[0297] Figure 18 shows that the toluene solution of CzPIPt exhibited absorption peaks around 340 nm, 327 nm, and 294 nm, with an emission wavelength peak at 416 nm (excitation wavelength 342 nm). Figure 19 shows that the thin film of CzPIPt exhibited absorption peaks around 344 nm, 331 nm, and 297 nm, with an emission wavelength peak around 425 nm (excitation wavelength 343 nm). These results demonstrate that CzPIPt, an organic compound according to one embodiment of the present invention, can be effectively used as a host transport material for luminescent materials and visible-range fluorescent materials.

[0298] Furthermore, it was found that the CzPIPt thin film exhibits good film quality, being less prone to aggregation and showing minimal changes even under atmospheric conditions.

[0299] Next, the HOMO and LUMO levels of CzPIPt were calculated based on cyclic voltammetry (CV) measurements. The calculation method was explained in Synthesis Example 1, so a repetitive description will be omitted.

[0300] As a result, the HOMO level of CzPIPt was found to be -5.89 eV by measuring the oxidation potential Ea [V], and the LUMO level of CzPIPt was found to be -2.30 eV by measuring the reduction potential Ec [V]. [Examples]

[0301] ≪Synthesis Example 3≫ This synthesis example specifically describes the synthesis method of 3-(1,2,4-triazolo[4,3-f]phenanthridine-3-yl)triphenylamine (abbreviated as mDPhATPt), which is shown as structural formula (165) in Embodiment 1. The structural formula of mDPhATPt is shown below.

[0302] [ka]

[0303] <Step 1: Synthesis of 3-(1,2,4-Triazolo[4,3-f]phenanthridine-3-yl)triphenylamine (abbreviation: mDPhATPt)> 1.5 g (3.9 mmol) of 3-(3-bromophenyl)-1,2,4-triazolo[4,3-f]phenanthridine, 0.67 g (4.0 mmol) of diphenylamine, 0.14 g (0.74 mmol) of copper(I) iodide, 0.14 g (0.52 mmol) of 18-crown-6-ether, 1.1 g (8.2 mmol) of potassium carbonate, and 3 mL of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU) were added to a 100 mL three-necked flask. This mixture was stirred under a nitrogen stream at 180 °C for 17 hours. After stirring, the mixture was cooled to room temperature and chloroform was added. The mixture was washed with water, saturated sodium bicarbonate aqueous solution, and saturated brine, and the organic layer was dried over magnesium sulfate. The mixture was filtered naturally, and the filtrate was concentrated to obtain an oily substance. The resulting oily substance was purified by silica gel column chromatography (toluene:ethyl acetate = 10:1). Methanol was added to this solid, and it was irradiated with ultrasound, after which the solid was recovered. The obtained solid was recrystallized with toluene to yield the target product as a pale yellow powder in a yield of 0.79 g and 43%.

[0304] 0.77 g of the obtained pale yellow powder was purified by sublimation using the train sublimation method under conditions of 3.2 Pa pressure, argon flow rate of 5.0 mL / min, and 240°C for 16 hours. After sublimation purification, 0.63 g of pale yellow powder was obtained with a recovery rate of 82%. The synthesis scheme for Step 1 is shown below.

[0305] [ka]

[0306] Nuclear magnetic resonance spectroscopy of the pale yellow powder obtained in step 1 above ( 1 The results of the analysis by 1H-NMR are shown below. 1 The 1H-NMR charts are shown in Figures 20A and 20B. From these, it can be seen that the organic compound mDPhATPt, which is the present invention, was obtained in this synthesis example.

[0307] 1H NMR (DMSO-d6, 300MHz): δ = 7.02-7.13 (m, 6H), 7.25-7.39 (m, 7H), 7.55-7.64 (m, 4H), 7.74-7.85 (m, 2H), 8.59-8.72 (m, 3H).

[0308] Next, Figure 21 shows the absorption and emission spectra of a toluene solution of mDPhATPt. Figure 22 shows the absorption and emission spectra of the thin film. The solid thin film was fabricated on a quartz substrate by vacuum deposition. A UV-Vis spectrophotometer (JASCO Corporation, V550 model) was used to measure the absorption spectra. The absorption spectrum of the solution was obtained by subtracting the absorption spectrum of the mDPhATPt solution (measured in a quartz cell) from the absorption spectrum of the mDPhATPt solution (measured in a quartz cell). The absorption spectrum of the thin film was obtained by subtracting the absorption spectrum of the quartz substrate from the absorption spectrum of the mDPhATPt film deposited on the quartz substrate. A fluorometer (Hamamatsu Photonics Ltd., FS920 model) was used to measure the emission spectra.

[0309] Figure 21 shows that the toluene solution of mDPhATPt exhibited absorption peaks around 301 nm and 282 nm, with an emission wavelength peak around 415 nm (excitation wavelength 306 nm). Figure 22 shows that the thin film of mDPhATPt exhibited absorption peaks around 304 nm, 281 nm, and 258 nm, with an emission wavelength peak around 418 nm (excitation wavelength 307 nm). These results demonstrate that mDPhATPt, an organic compound according to one embodiment of the present invention, can be effectively used as a host transport material for luminescent materials and visible-range fluorescent materials.

[0310] Furthermore, it was found that the mDPhATPt thin film exhibits good film quality, being less prone to aggregation and showing minimal morphological changes even under atmospheric conditions.

[0311] The HOMO and LUMO levels of mDPhATPt were calculated based on cyclic voltammetry (CV) measurements. The calculation method was explained in Synthesis Example 1, so a repetitive description is omitted.

[0312] Measurements of the oxidation potential Ea [V] revealed that the HOMO level of mDPhATPt is -5.62 eV. Furthermore, measurements of the reduction potential Ec [V] revealed that the LUMO level of mDPhATPt is -2.36 eV. Repeated oxidation-reduction wave measurements showed that mDPhATPt maintained a peak intensity of 91% in the Ea measurement, confirming its excellent resistance to oxidation. [Examples]

[0313] This example describes a light-emitting device 1 according to one aspect of the present invention and a comparative light-emitting device 1, which is a comparative example. The structural formulas of the organic compounds used in this example are shown below.

[0314] [ka]

[0315] (Method for fabricating light-emitting device 1) First, a film of indium tin oxide (ITSO) containing silicon oxide was deposited on a glass substrate by sputtering to form the first electrode 101. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.

[0316] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0317] Then, 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0318] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. On the first electrode 101, a hole injection layer 111 is formed by co-depositing 4,4'-di(carbazol-9-yl)biphenyl (abbreviated as CBP) represented by the above structural formula (i) and molybdenum oxide at a weight ratio of 4:2 (=CBP:molybdenum oxide) to a thickness of 60 nm using a deposition method with resistance heating.

[0319] Next, a hole transport layer 112 was formed by depositing 1,3-bis(carbazol-9-yl)benzene (abbreviated as mCP), represented by the above structural formula (ii), to a thickness of 20 nm onto the hole injection layer 111.

[0320] Next, mCP and tris[3-(4-fluorophenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviated as [Ir(iPrFptz)3]), represented by the above structural formula (iii), are co-deposited at a weight ratio of 1:0.08 (=mCP:[Ir(iPrFptz)3]) at a density of 10 nm to form the first luminescent layer. Then, 3-[4-(carbazole-9-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviated as CzPIPt), represented by the above structural formula (iv), and [Ir(iP A second light-emitting layer was formed by co-depositing 20 nm of [rFptz)3] in a weight ratio of 1:0.08 (=CzPIPt:[Ir(iPrFptz)3]) and then co-depositing 3-[4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviated as DBTPIPt-II) represented by the above structural formula (v) and [Ir(iPrFptz)3] in a weight ratio of 1:0.08 (=DBTPIPt-II:[Ir(iPrFptz)3])20 nm to form a third light-emitting layer, thereby forming light-emitting layer 113.

[0321] Subsequently, a layer of bathophenanthroline (abbreviated as Bphen), represented by the above structural formula (vi), was deposited onto the light-emitting layer 113 to a thickness of 15 nm to form an electron transport layer 114.

[0322] After forming the electron transport layer 114, a lithium fluoride (LiF) layer 1 nm thick was deposited to form an electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm to form a second electrode 102, thereby fabricating the light-emitting device 1 of this embodiment.

[0323] (Method for fabricating light-emitting device 2) Light-emitting device 2 was fabricated in the same way as light-emitting device 1, except that CzPIPt was replaced with DBTPIPt-II.

[0324] (Method for fabricating comparative light-emitting device 1) Comparative light-emitting device 1 was fabricated in the same manner as light-emitting device 1, except that CzPIPt was replaced with 3-[4-(9H-carbazole-9-yl)phenyl]-1,2,4-triazolo[4,3-f]phenanthidine (abbreviated as CzTPt), represented by the above structural formula (vii), and DBTPIPt-II was replaced with 3-[4-(dibenzothiophen-4-yl)phenyl]-1,2,4-triazolo[4,3-f]phenanthidine (abbreviated as DBTTPt-II), represented by the above structural formula (viii).

[0325] (Method for fabricating comparative light-emitting device 2) Comparative light-emitting device 2 was fabricated in the same way as light-emitting device 2, except that DBTPIPt-II was replaced with DBTTPt-II.

[0326] The stacked structures of the above-mentioned light-emitting device 1, light-emitting device 2, comparative light-emitting device 1, and comparative light-emitting device 2 are summarized in the table below.

[0327] [Table 1]

[0328] After sealing these light-emitting devices with a glass substrate in a glove box under a nitrogen atmosphere so as not to be exposed to air (applying a sealing material around the elements and performing UV treatment and heat treatment at 80°C for 1 hour during sealing), measurements were made on the initial characteristics.

[0329] The luminance-current density characteristics of Light-Emitting Device 1, Light-Emitting Device 2, Comparative Light-Emitting Device 1, and Comparative Light-Emitting Device 2 are shown in Fig. 23, the current efficiency-luminance characteristics are shown in Fig. 24, the luminance-voltage characteristics are shown in Fig. 25, the current-voltage characteristics are shown in Fig. 26, the external quantum efficiency-luminance characteristics are shown in Fig. 27, and the emission spectra are shown in Fig. 28. Also, the main characteristics of Light-Emitting Device 1 around 1000 cd / m 2 are shown in Table 2. A color luminance meter (Topcon, BM-5A) was used for measuring luminance and CIE chromaticity, and a multi-channel spectroscope (Hamamatsu Photonics, PMA-11) was used for measuring the emission spectrum. Also, the measurements of each light-emitting device were performed at room temperature (an atmosphere maintained at 23°C).

[0330]

Table 2

[0331] From Fig. 28, it can be seen that emissions derived from [Ir(iPrFptz)3], which is a blue phosphorescent dopant, are obtained for Light-Emitting Device 1, Light-Emitting Device 2, Comparative Light-Emitting Device 1, and Comparative Light-Emitting Device 2 of one aspect of the present invention. Also, from Fig. 27, it was found that Light-Emitting Device 1 and Light-Emitting Device 2 of one aspect of the present invention have good external quantum efficiency. That is, CzPIPt and DBTPIPt-II of one aspect of the present invention were found to be suitable as host materials for the light-emitting layer of blue phosphorescent elements, and particularly CzPIPt was found to be good. Therefore, it was found that CzPIPt and DBTPIPt-II are organic compounds having a high T1 level and can be used as hosts for blue phosphorescent materials. Also, from Fig. 26, it was found that Light-Emitting Device 1 and Light-Emitting Device 2 of one aspect of the present invention can be driven at a sufficiently low driving voltage.

[0332] Also, the initial luminance of 300 cd / m2 Figure 29 shows the change in brightness with respect to operating time under the condition of constant current density. As shown in Figure 29, it was found that light-emitting devices 1 and 2, which are light-emitting devices according to one embodiment of the present invention, are light-emitting devices with good lifespan. On the other hand, comparative light-emitting device 1, which showed good characteristics in initial characteristics, was found to be a light-emitting device with a rapid decrease in brightness and a short lifespan. [Examples]

[0333] This example describes a light-emitting device 3 according to one embodiment of the present invention and a comparative light-emitting device 3 as a comparative example. The structural formulas of the organic compounds used in this example are shown below.

[0334] [ka]

[0335] (Method for fabricating light-emitting device 3) First, a film of indium tin oxide (ITSO) containing silicon oxide was deposited on a glass substrate by sputtering to form the first electrode 101. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.

[0336] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0337] Then, 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0338] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. Then, a hole injection layer 111 is formed on the first electrode 101 by co-depositing 4,4'-di(carbazole-9-yl)biphenyl (abbreviated as CBP), represented by the above structural formula (i), and molybdenum oxide at a weight ratio of 4:2 (=CBP:molybdenum oxide) to a thickness of 60 nm using a deposition method with resistance heating.

[0339] Next, a hole transport layer 112 was formed by depositing 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), represented by the above structural formula (ix), onto the hole injection layer 111 to a thickness of 30 nm.

[0340] Next, 3-(1,2,4-triazolo[4,3-f]phenanthridine-3-yl)triphenylamine (abbreviated as mDPhATPt), represented by the above structural formula (x), and tris(2-phenylpyridinato-N,C2')iridium(III) (abbreviated as [Ir(ppy)3]), represented by the above structural formula (xi), were co-deposited at a weight ratio of 1:0.08 (=mDPhATPt:[Ir(ppy)3]) at a density of 30 nm to form an emissive layer 113.

[0341] Subsequently, 3-[4-(dibenzothiophen-4-yl)phenyl]-1,2,4-triazolo[4,3-f]phenanthridine (abbreviated as DBTTPt-II), represented by the above structural formula (viii), was deposited onto the light-emitting layer 113 to a thickness of 15 nm to form a first electron transport layer. Then, bathophenanthroline (abbreviated as Bphen), represented by the above structural formula (vi), was deposited to a thickness of 15 nm to form a second electron transport layer, thus forming the electron transport layer 114.

[0342] After forming the electron transport layer 114, a lithium fluoride (LiF) layer 1 nm thick was deposited to form an electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm to form a second electrode 102, thereby fabricating the light-emitting device 3 of this embodiment.

[0343] (Method for fabricating comparative light-emitting device 3) Comparative light-emitting device 3 was fabricated in the same manner as light-emitting device 3, except that mDPhATPt in light-emitting device 3 was replaced with 3-[3-(9H-carbazole-9-yl)phenyl]-1,2,4-triazolo[4,3-f]phenanthridine (abbreviated as mCzTPt), represented by the above structural formula (xii).

[0344] The stacked structures of the above-mentioned light-emitting device 3 and comparative light-emitting device 3 are summarized in the table below.

[0345] [Table 3]

[0346] The light-emitting device 3 and the comparative light-emitting device 3 were sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the initial characteristics of the light-emitting devices were measured.

[0347] Figure 30 shows the luminance-current density characteristics of light-emitting device 1 and comparative light-emitting device 3, Figure 31 shows the current efficiency-luminance characteristics, Figure 32 shows the luminance-voltage characteristics, Figure 33 shows the current-voltage characteristics, Figure 34 shows the external quantum efficiency-luminance characteristics, Figure 35 shows the luminance-power efficiency characteristics, and Figure 36 shows the emission spectra of light-emitting device 3 and comparative light-emitting device 3 at 1000 cd / m². 2 Table 4 shows the main characteristics of the vicinity. A colorimeter (Topcon BM-5A) was used to measure luminance and CIE chromaticity, and a multi-channel spectrometer (Hamamatsu Photonics PMA-11) was used to measure the emission spectrum. Measurements of each light-emitting device were performed at room temperature (in an atmosphere maintained at 23°C).

[0348] [Table 4]

[0349] Figure 36 shows that the light-emitting device 3 of one embodiment of the present invention and the comparative light-emitting device 3 produce light originating from the green phosphorescent dopant [Ir(ppy)3]. Furthermore, Figures 31, 34, and 35 show that the light-emitting device 3 of one embodiment of the present invention is an EL device with better current efficiency, external quantum efficiency, and power efficiency than the comparative light-emitting device 3. Also, Figure 33 shows that the light-emitting device 3 of one embodiment of the present invention is a light-emitting device with a low driving voltage and low power consumption. From the above, it was found that mDPhATPt of one embodiment of the present invention is suitable as a host material for the light-emitting layer of a green phosphorescent element.Therefore, it was found that mDPhATPt is an organic compound with a high T1 level that can be used as a host for green phosphorescent materials. [Examples]

[0350] This example describes a light-emitting device 4 according to one aspect of the present invention and a comparative light-emitting device 4 as a comparative example. The structural formulas of the organic compounds used in this example are shown below.

[0351] [ka]

[0352] (Method for fabricating light-emitting device 4) First, a film of indium tin oxide (ITSO) containing silicon oxide was deposited on a glass substrate by sputtering to form the first electrode 101. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.

[0353] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0354] Then, 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0355] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. Then, a hole injection layer 111 is formed on the first electrode 101 by co-depositing 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), represented by the above structural formula (ix), and molybdenum oxide in a weight ratio of 4:2 (=BPAFLP:molybdenum oxide) to a thickness of 50 nm using a deposition method with resistance heating.

[0356] Next, a hole transport layer 112 was formed by depositing BPAFLP onto the hole injection layer 111 to a thickness of 20 nm.

[0357] Next, 3-[4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviated as DBTPIPt-II), represented by the above structural formula (v), and tris(2-phenylpyridinato-N,C2')iridium(III) (abbreviated as [Ir(ppy)3]), represented by the above structural formula (xi), were co-deposited at a weight ratio of 1:0.06 (=DBTPIPt-II:[Ir(ppy)3]) at a density of 30 nm to form the light-emitting layer 113.

[0358] Subsequently, DBTPIPt-II was deposited on the light-emitting layer 113 to a thickness of 30 nm to form a first electron transport layer. Then, bathophenanthroline (abbreviated as Bphen), represented by the above structural formula (vi), was deposited to a thickness of 15 nm to form a second electron transport layer, thereby forming the electron transport layer 114.

[0359] After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm to form the second electrode 102, thereby fabricating the light-emitting device 4 of this embodiment.

[0360] (Method for fabricating comparative light-emitting device 4) Comparative light-emitting device 4 is a light-emitting device that uses the same phosphorescent dopant as light-emitting device 4. Comparative light-emitting device 4 was fabricated by replacing BPAFLP in the hole injection layer of light-emitting device 4 with 4,4-di(N-carbazol)biphenyl (abbreviated as CBP) represented by the above structural formula (i), BPAFLP in the hole transport layer with 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP) represented by the above structural formula (xiii), DBTPIPt-II in the light-emitting layer with 7-[3-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviated as 7mDBTPIPt-II) represented by the above structural formula (xiv), and DBTPIPt-II in the electron transport layer with N-phenyl-2-[3-(dibenzothiophen-4-yl)phenyl]benzimidazole (abbreviated as mDBTBIm-II) represented by the above structural formula (xv). Furthermore, the film thicknesses of the hole injection layer 111, the light-emitting layer 113, and the second electron transport layer were set to 60 nm, 40 nm, and 20 nm, respectively. The materials and film thicknesses in comparative light-emitting device 4 are the same as those in light-emitting device 4, except for those mentioned above.

[0361] The stacked structures of the above-mentioned light-emitting device 4 and comparative light-emitting device 4 are summarized in the table below.

[0362] [Table 5]

[0363] The above-mentioned light-emitting device 4 and comparative light-emitting device 4 were sealed with a glass substrate in a glove box under a nitrogen atmosphere to prevent exposure to the atmosphere (sealing material was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour). After this, the initial characteristics of the light-emitting devices were measured.

[0364] The luminance-current density characteristics of light-emitting device 4 and comparative light-emitting device 4 are shown in Figure 37, the current efficiency-luminance characteristics in Figure 38, the luminance-voltage characteristics in Figure 39, the current-voltage characteristics in Figure 40, the external quantum efficiency-luminance characteristics in Figure 41, the luminance-power efficiency characteristics in Figure 42, and the emission spectra in Figure 43. Furthermore, the luminance of light-emitting device 4 and comparative light-emitting device 4 at 1000 cd / m² is also shown. 2 Table 6 shows the main characteristics of the vicinity. A colorimeter (Topcon, BM-5A) was used to measure luminance and CIE chromaticity, and a multi-channel spectrometer (Hamamatsu Photonics, PMA-11) was used to measure the emission spectrum. Measurements of each light-emitting device were performed at room temperature (in an atmosphere maintained at 23°C).

[0365] [Table 6]

[0366] Figure 43 shows that the light-emitting device 4 of one embodiment of the present invention and the comparative light-emitting device 4 produce light originating from the green phosphorescent dopant [Ir(ppy)3]. Furthermore, Figures 38, 41, and 42 show that the light-emitting device 4 of one embodiment of the present invention is an EL device with better current efficiency, external quantum efficiency, and power efficiency than the comparative light-emitting device 4. Furthermore, Figure 40 shows that the light-emitting device 4 of one embodiment of the present invention is a light-emitting device with a low driving voltage and low power consumption. From the above, it was found that DBTPIPt-II of one embodiment of the present invention is suitable as a host material for the light-emitting layer of a green phosphorescent element. From this, it was found that DBTPIPt-II is an organic compound with a high T1 level that can be used as a host for green phosphorescent materials. This suggests that attaching the substituent at the 3-position of the 4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine skeleton, as in DBTPIPt-II, results in a higher T1 level, allowing for the excitation of shorter wavelength phosphorescent dopants and thus higher efficiency, compared to attaching the substituent at the 7-position of the 4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine skeleton, as in 7mDBTPIPt-II. Furthermore, DBTPIPt-II was found to be suitable when used as an electron transport layer because it exhibits high electron transport properties and allows for a lower driving voltage. [Examples]

[0367] In this example, a light-emitting device 5 according to one embodiment of the present invention described in the embodiments and a comparative light-emitting device 5, which is a comparative example, will be described. The structural formulas of the organic compounds used in this example are shown below.

[0368] [ka]

[0369] (Method for fabricating light-emitting device 5) First, a film of indium tin oxide (ITSO) containing silicon oxide was deposited on a glass substrate by sputtering to form the first electrode 101. The film thickness was 110 nm, and the electrode area was 2 mm × 2 mm.

[0370] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0371] Then, 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0372] Next, the substrate on which the first electrode 101 is formed is fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 is formed faces downwards. On the first electrode 101, a hole injection layer 111 is formed by co-depositing 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), represented by the above structural formula (ix), and molybdenum oxide in a weight ratio of 2:1 (=BPAFLP:molybdenum oxide) to a thickness of 50 nm using a deposition method with resistance heating.

[0373] Next, a hole transport layer 112 was formed by depositing BPAFLP onto the hole injection layer 111 to a thickness of 20 nm.

[0374] Next, we have 3-[4-(carbazole-9-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviated as CzPIPt), represented by the above structural formula (iv), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP), represented by the above structural formula (xvi), and tris(2-phenylpyridinato-N,C2')yl, represented by the above structural formula (xi). A first light-emitting layer was formed by co-depositing 20 nm of Dium(III) (abbreviation: [Ir(ppy)3]) in a weight ratio of 1:0.3:0.06 (=CzPIPt:PCBA1BP:[Ir(ppy)3]) with Dium(III) (abbreviation:[Ir(ppy)3]). Then, a second light-emitting layer 113 was formed by co-depositing CzPIPt and [Ir(ppy)3] in a weight ratio of 1:0.06 (=CzPIPt:[Ir(ppy)3]).

[0375] Subsequently, CzPIPt was deposited on the light-emitting layer 113 to a thickness of 15 nm to form a first electron transport layer, and then bathophenanthroline (abbreviated as Bphen), represented by the above structural formula (vi), was deposited to a thickness of 15 nm to form a second electron transport layer, thereby forming the electron transport layer 114.

[0376] After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm to form the second electrode 102, thereby fabricating the light-emitting device 5 of this embodiment.

[0377] (Method for fabricating comparative light-emitting device 5) The comparative light-emitting device 5 is a light-emitting device having the same phosphorescent dopant as the light-emitting device 5. In the comparative light-emitting device 5, BPAFLP in the hole injection layer of the light-emitting device 5 is changed to 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (xvii), BPAFLP used in the hole transport layer and PCBA1BP used in the first light-emitting layer are changed to 3,3’-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP) represented by the above structural formula (xiii), and CzPIPt used in the light-emitting layer and the first electron transport layer is changed to 2-[3-(carbazol-9-yl)phenyl]imidazo[1,2-f]phenanthridine (abbreviation: 2mCzPIPt) represented by the above structural formula (xviii). Further, the film thickness of the hole injection layer 111 is 60 nm, and the film thickness of the first electron transport layer is 10 nm. Materials and film thicknesses other than those described above in the comparative light-emitting device 5 are the same as those in the light-emitting device 5.

[0378] The stacked structures of the above light-emitting device 5 and comparative light-emitting device 5 are summarized in the following table.

[0379]

Table 7

[0380] After the above light-emitting device 5 and comparative light-emitting device 5 were sealed with a glass substrate so as not to be exposed to air in a glove box under a nitrogen atmosphere (a sealing material was applied around the element, and UV treatment and heat treatment were performed at 80 °C for 1 hour during sealing), the initial characteristics were measured.

[0381] The luminance-current density characteristics, current efficiency-luminance characteristics, luminance-voltage characteristics, current-voltage characteristics, external quantum efficiency-luminance characteristics, luminance-power efficiency characteristics, and emission spectra of the light-emitting device 5 and the comparative light-emitting device 5 are shown in FIGS. 44, 45, 46, 47, 48, 49, and 50, respectively. Also, for the light-emitting device 5 and the comparative light-emitting device 5 at 1000 cd / m 2Table 8 shows the main characteristics of the vicinity. A colorimeter (Topcon, BM-5A) was used to measure luminance and CIE chromaticity, and a multi-channel spectrometer (Hamamatsu Photonics, PMA-11) was used to measure the emission spectrum. Measurements of each light-emitting device were performed at room temperature (in an atmosphere maintained at 23°C).

[0382] [Table 8]

[0383] Figure 50 shows that the light-emitting device 5 of one embodiment of the present invention and the comparative light-emitting device 5 produce light originating from the green phosphorescent dopant [Ir(ppy)3]. Figures 45, 48, and 49 show that the light-emitting device 5 of one embodiment of the present invention is a light-emitting device with better current efficiency, external quantum efficiency, and power efficiency than the comparative light-emitting device 5. Furthermore, Figure 47 shows that the light-emitting device 5 of one embodiment of the present invention is a light-emitting device with a low driving voltage and low power consumption. From the above, it was found that CzPIPt of one embodiment of the present invention is suitable as a host material for the light-emitting layer of a green phosphorescent element. Therefore, it was found that CzPIPt is an organic compound with a high T1 level that can be used as a host for green phosphorescent materials. This suggests that attaching a substituent at the 3-position of the 4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine skeleton, as in CzPIPt, results in a higher T1 level, allowing for the excitation of shorter wavelength phosphorescent dopants and thus higher efficiency, compared to attaching a substituent at the 2-position of the 4-(dibenzothiophen-4-yl)phenyl]imidazo[1,2-f]phenanthridine skeleton, as in 2mCzPIPt. Furthermore, it was found that CzPIPt is suitable when used as a material to constitute the electron transport layer because it exhibits high electron transport properties and allows for a lower driving voltage. [Explanation of Symbols]

[0384] 101: First electrode, 102: Second electrode, 103: EL layer, 111: Hole injection layer, 112: Hole transport layer, 113: Light-emitting layer, 114: Electron transport layer, 115: Electron injection layer, 116: Charge generation layer, 117: P-type layer, 118: Electron relay layer, 119: Electron injection buffer layer, 400: Substrate, 401: First electrode, 403: EL layer, 404: Second electrode, 405: Sealing material, 406: Sealing material, 407: Encapsulation substrate, 412: Pad, 420: IC chip, 501: Anode, 502: Cathode, 511: First light-emitting unit, 512: Second light-emitting unit, 513: Charge generation Layer, 601: Drive circuit section (source line drive circuit), 602: Pixel section, 603: Drive circuit section (gate line drive circuit), 604: Encapsulation substrate, 605: Sealing material, 607: Space, 608: Wiring, 609: FPC (Flexible Printed Circuit), 610: Element substrate, 611: Switching FET, 612: Current control FET, 613: First electrode, 614: Insulator, 616: EL layer, 617: Second electrode, 618: Light-emitting device, 951: Substrate, 952: Electrode, 953: Insulating layer, 954: Partition layer, 955: EL layer, 956: Electrode, 1001: Substrate, 1002: Underlayer insulating film, 1003: Gate insulating film, 1006: Gate electrode, 1007: Gate electrode, 1008: Gate electrode, 1020: First interlayer insulating film, 1021: Second interlayer insulating film, 1022: Electrode, 1024W: First electrode, 1024R: First electrode, 1024G: First electrode, 1024B: First electrode, 1025: Partition, 1028: EL layer, 1029: Second electrode, 1031: Encapsulation substrate, 1032: Seal material, 1033: Transparent substrate, 1034R: Red colored layer, 1034G: Green colored layer, 1034B: Blue colored layer, 1035: Black matrix, 1 036: Overcoat layer, 1037: Third interlayer insulating film, 1040: Pixel section, 1041: Drive circuit section, 1042: Peripheral section, 2001: Housing, 2002: Light source, 2100: Robot, 2110: Processing unit, 2101: Illuminance sensor, 2102: Microphone, 2103: Upper camera, 2104: Speaker, 2105: Display, 2106: Lower camera, 2107: Obstacle sensor, 2108: Moving mechanism, 3001: Lighting device, 5000: Housing, 5001: Display section, 5002: Display section, 5003: Speaker, 5004: LED lamp, 5006: Connection terminal,5007: Sensor, 5008: Microphone, 5012: Support part, 5013: Earphone, 5100: Cleaning robot, 5101: Display, 5102: Camera, 5103: Brush, 5104: Operation button, 5150: Portable information terminal, 5151: Housing, 5152: Display area, 5153: Bending part, 5120: Dust, 5200: Display area, 5201: Display area, 5202: Display area, 5203: Display area, 7101: Housing, 7103: Display unit, 7105: Stand, 7 107: Display unit, 7109: Operation keys, 7110: Remote control unit, 7201: Main unit, 7202: Enclosure, 7203: Display unit, 7204: Keyboard, 7205: External connection port, 7206: Pointing device, 7210: Second display unit, 7401: Enclosure, 7402: Display unit, 7403: Operation buttons, 7404: External connection port, 7405: Speaker, 7406: Microphone, 9310: Portable information terminal, 9311: Display panel, 9313: Hinge, 9315: Enclosure,

Claims

[Claim 1] An organic compound represented by the general formula (G1). 【Chemistry 1】 (However, in the above general formula (G1), X represents nitrogen or substituted or unsubstituted carbon, and Ar represents a substituted or unsubstituted arylene group having 6 to 12 carbon atoms. Also, R １ ~R ８ Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C7 cyclic alkyl group, or a substituted or unsubstituted C6 to C13 aryl group. Furthermore, A represents a substituted or unsubstituted diarylamino group when X is nitrogen, and when X is carbon, it represents one of the following: a substituted or unsubstituted diarylamino group, a substituted or unsubstituted carbazolyl group, a substituted or unsubstituted dibenzothiophenyl group, or a substituted or unsubstituted dibenzofuranyl group.

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