Organic compounds, light-emitting devices, electronic devices, electronic equipment, light-emitting devices, and lighting devices

Abstract

The present invention provides an organic compound which is likely to exhibit thermally activated delayed fluorescence (TADF). The present invention provides an organic compound which is represented by general formula (G1). In general formula (G1), each of R1 to R8 independently represents a hydrogen atom, an alkyl group having from 1 to 6 carbon atoms, a cycloalkyl group having from 3 to 7 carbon atoms, or a substituted or unsubstituted diarylamino group; at least one of the R1 to R8 moieties represents a substituted or unsubstituted diarylamino group; α represents a substituted or unsubstituted phenylene group; n represents an integer from 0 to 4; and A represents a substituted or unsubstituted benzoflopyrimidine skeleton or a benzothienopyrimidine skeleton.

Description

[Technical field]

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

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

[0003] Since such light-emitting devices are self-luminous, when used as display pixels, they have advantages such as high visibility and no need for backlighting compared to liquid crystals, making them suitable for use as flat panel display elements. Another major advantage of displays using such light-emitting devices is that they can be made thin and lightweight. Another characteristic is that they have an extremely fast response speed.

[0004] In addition, these light-emitting devices can have a two-dimensional light-emitting layer that is continuously formed, making it possible to obtain surface light emission. This is a feature that is difficult to obtain with point light sources such as incandescent light bulbs and LEDs, or linear light sources such as fluorescent lamps, making them highly valuable as surface light sources for lighting and other applications.

[0005] Displays and lighting devices using such light-emitting devices are suitable for use in a variety of electronic devices, but research and development is ongoing to find light-emitting devices with better characteristics (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2016-174161 A Summary of the Invention [Problem to be solved by the invention]

[0007] An object of one embodiment of the present invention is to provide a novel organic compound.Another object of one embodiment of the present invention is to provide an organic compound that is likely to exhibit delayed fluorescence and thermally activated delayed fluorescence (TADF).Another object of one embodiment of the present invention is to provide an organic compound that exhibits TADF emission.Another object of one embodiment of the present invention is to provide an organic compound that can provide a light-emitting element with high emission efficiency.

[0008] Another object of one embodiment of the present invention is to provide a light-emitting device with high emission efficiency, or to provide a light-emitting device that exhibits TADF emission.

[0009] Another object of one embodiment of the present invention is to provide a light-emitting device, an electronic device, a display device, and an electronic device each with low power consumption.

[0010] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract effects other than these from the description in the specification, drawings, claims, etc.

[0011] It is sufficient for the present invention to solve any one of the above problems. [Means for solving the problem]

[0012] One embodiment of the present invention is an organic compound represented by the following general formula (G1).

[0013] [ka]

[0014] In the above general formula (G1), R 1 ~R 8 Each of R is independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group. 1 ~R 8 At least one of the groups is a substituted or unsubstituted diarylamino group. In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. In addition, A represents a substituted or unsubstituted benzofuropyrimidine skeleton or benzothienopyrimidine skeleton.

[0015] Another embodiment of the present invention is an organic compound in which A in the above structure is a group represented by general formula (g1):

[0016] [ka]

[0017] In the above general formula (g1), R 11 ~R16 One of the groups is a bond, and the rest are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. Q represents an oxygen atom or a sulfur atom.

[0018] Another embodiment of the present invention is an organic compound represented by the following general formula (G2).

[0019] [ka]

[0020] In the above general formula (G2), R 1 ~R 8 Each of R is independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group. 1 ~R 8 At least one of R is a substituted or unsubstituted diarylamino group. α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. 11 ~R 15 are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0021] Another embodiment of the present invention is an organic compound having the above structure, in which the substituted or unsubstituted diarylamino group is a group represented by the following general formula (g2):

[0022] [ka]

[0023] In the above general formula (g2), Ar 1 and Ar 2each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

[0024] Alternatively, another embodiment of the present invention is a method for manufacturing a semiconductor device comprising the steps of: 3 and R 6 or both of which are a group represented by general formula (g2).

[0025] Another embodiment of the present invention is an organic compound represented by the following general formula (G3).

[0026] [ka]

[0027] In the above general formula (G3), Ar 3 ~Ar 6 Each of R is independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. 1 , R 2 , R 4 , R 5 , R 7 and R 8 are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a cycloalkyl group having 3 to 7 carbon atoms. In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. In addition, R 11 ~R 15 are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0028] Another embodiment of the present invention is an organic compound represented by the following general formula (G4).

[0029] [ka]

[0030] In the above general formula (G4), Ar 3 ~Ar 6 are each independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. 13 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0031] Another embodiment of the present invention is an organic compound represented by the following general formula (G5).

[0032] [ka]

[0033] In the above general formula (G5), Ar 3 ~Ar 6 Each of R is independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. 13 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0034] Another embodiment of the present invention is an organic compound represented by the following structural formula (100):

[0035] [ka]

[0036] Another embodiment of the present invention is an organic compound represented by the following structural formula (101).

[0037] [ka]

[0038] Another embodiment of the present invention is an organic compound represented by the following structural formula (102).

[0039] [ka]

[0040] Another embodiment of the present invention is an organic compound having the above structure, in which the difference between the lowest singlet excitation level and the lowest triplet excitation level is 0.2 eV or less.

[0041] Another embodiment of the present invention is an organic compound having the above structure, in which the difference between the lowest singlet excitation level and the lowest triplet excitation level is 0.1 eV or less.

[0042] Another embodiment of the present invention is an organic compound having the above structure, in which Q is an oxygen atom.

[0043] Alternatively, another embodiment of the present invention is an electronic device having a first electrode, a second electrode, and an organic layer sandwiched between the first electrode and the second electrode, wherein the organic layer contains an organic compound having the above-described structure.

[0044] Alternatively, another embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, and an organic layer sandwiched between the first electrode and the second electrode, wherein the organic layer contains an organic compound having the above-described structure.

[0045] Alternatively, another embodiment of the present invention is a light-emitting device having the above-described structure, wherein the organic layer has a light-emitting layer, and the organic compound is contained in the light-emitting layer.

[0046] Alternatively, another aspect of the present invention is a light-emitting device having the above-described structure, in which the light emitted from the organic layer is delayed fluorescence.

[0047] Alternatively, another aspect of the present invention is a light-emitting device having the aforementioned configuration, wherein the transient lifetime of the delayed fluorescence is not less than 100 nanoseconds and not more than 10 milliseconds.

[0048] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, in which the light-emitting layer further contains a fluorescent material.

[0049] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the light-emitting layer further contains a phosphorescent material.

[0050] Another embodiment of the present invention is an electronic device including any of the above light-emitting devices and a sensor, an operation button, a speaker, or a microphone.

[0051] Another embodiment of the present invention is a light-emitting device including any of the above light-emitting devices and a transistor or a substrate.

[0052] Another embodiment of the present invention is a lighting device including any of the above light-emitting devices and a housing.

[0053] In this specification, the term "light-emitting device" includes an image display device using a light-emitting device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or TCP (Tape Carrier Package), is attached to a light-emitting device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (integrated circuit) is directly mounted on a light-emitting device by a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may have a light-emitting device. Effect of the Invention

[0054] According to one embodiment of the present invention, a novel organic compound can be provided. Alternatively, according to one embodiment of the present invention, an organic compound that is likely to exhibit thermally activated delayed fluorescence (TADF) can be provided. Alternatively, according to one embodiment of the present invention, an organic compound that exhibits TADF emission can be provided. Alternatively, according to one embodiment of the present invention, an organic compound that can provide a light-emitting element with high emission efficiency can be provided.

[0055] According to one embodiment of the present invention, a light-emitting device having high emission efficiency or exhibiting TADF emission can be provided.

[0056] According to one embodiment of the present invention, a light-emitting device, an electronic device, a display device, and an electronic device each having low power consumption can be provided.

[0057] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract effects other than these from the description in the specification, drawings, claims, etc. [Brief description of the drawings]

[0058] 1A, 1B and 1C are conceptual diagrams of a light emitting device. 2A, 2B, 2C, and 2D are diagrams illustrating an example of a method for fabricating a light-emitting device. FIG. 3 is a diagram showing an example of a method for producing a light-emitting device. 4A and 4B are conceptual diagrams of an active matrix type light emitting device. 5A and 5B are conceptual diagrams of an active matrix type light emitting device. FIG. 6 is a conceptual diagram of an active matrix type light emitting device. 7A and 7B are conceptual diagrams of a passive matrix type light emitting device. 8A and 8B are diagrams illustrating a lighting device. 9A, 9B1, 9B2 and 9C are conceptual diagrams showing electronic devices. 10A, 10B and 10C are conceptual diagrams showing electronic devices. FIG. 11 is a conceptual diagram showing a lighting device. FIG. 12 is a conceptual diagram showing a lighting device. FIG. 13 shows a concept of an in-vehicle display device and lighting device. 14A and 14B are conceptual diagrams showing electronic devices. 15A, 15B and 15C are conceptual diagrams showing electronic devices. Figures 16A and 16B show the 1 1 H NMR chart. FIG. 17 shows the absorption and emission spectra of 4DPhA2CzBfpm in a solution state. FIG. 18 shows the absorption and emission spectra of 4DPhA2CzBfpm in a thin film state. FIG. 19 is the phosphorescence spectrum of 4DPhA2CzBfpm. Figures 20A and 20B show the 1 1 H NMR chart. FIG. 21 shows the absorption and emission spectra of 8Ph-4DPhA2CzBfpm in a solution state. FIG. 22 shows the absorption and emission spectra of 8Ph-4DPhA2CzBfpm in a thin film state. FIG. 23 is the phosphorescence spectrum of 8Ph-4DPhA2CzBfpm. Figures 24A and 24B show the 1 1 H NMR chart. FIG. 25 shows the absorption and emission spectra of 4DPhACzBfpm in a solution state. FIG. 26 shows the absorption and emission spectra of 4DPhACzBfpm in a thin film state. FIG. 27 is the phosphorescence spectrum of 4DPhACzBfpm. FIG. 28 is a diagram showing the distribution of HOMO and LUMO of the organic compounds represented by the structural formulas (100) to (102). FIG. 29 is a diagram showing the distribution of HOMO and LUMO of the organic compounds represented by the structural formula (103) and the structural formula (104). FIG. 30 is a graph showing the luminance-current density characteristics of the light-emitting device 1. As shown in FIG. FIG. 31 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 1. As shown in FIG. FIG. 32 is a graph showing the luminance-voltage characteristics of the light-emitting device 1. As shown in FIG. FIG. 33 is a graph showing the current-voltage characteristics of the light-emitting device 1. As shown in FIG. FIG. 34 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 1. As shown in FIG. FIG. 35 is a graph showing the emission spectrum of the light-emitting device 1. As shown in FIG. 36A and 36B are graphs illustrating the transient EL characteristics of light-emitting device 1. FIG. FIG. 37 is a graph showing the luminance-current density characteristics of the light-emitting device 2. As shown in FIG. FIG. 38 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 2. As shown in FIG. FIG. 39 is a graph showing the luminance-voltage characteristics of the light-emitting device 2. As shown in FIG. FIG. 40 is a graph showing the current-voltage characteristics of the light-emitting device 2. As shown in FIG. FIG. 41 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 2. As shown in FIG. FIG. 42 is a graph showing the emission spectrum of the light-emitting device 2. As shown in FIG. FIG. 43 is a graph showing the luminance-current density characteristics of the light-emitting device 3. As shown in FIG. FIG. 44 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 3. As shown in FIG. FIG. 45 is a graph showing the luminance-voltage characteristics of the light-emitting device 3. As shown in FIG. FIG. 46 is a graph showing the current-voltage characteristics of the light-emitting device 3. As shown in FIG. FIG. 47 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 3. As shown in FIG. FIG. 48 is a graph showing the emission spectrum of the light-emitting device 3. As shown in FIG. 49A and 49B are graphs illustrating the transient EL characteristics of light-emitting device 3. FIG. FIG. 50 is a graph showing the luminance-current density characteristics of the light-emitting device 4. As shown in FIG. FIG. 51 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 4. As shown in FIG. FIG. 52 is a graph showing the luminance-voltage characteristics of the light-emitting device 4. As shown in FIG. FIG. 53 is a graph showing the current-voltage characteristics of the light-emitting device 4. As shown in FIG. FIG. 54 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 4. As shown in FIG. FIG. 55 is a graph showing the emission spectrum of the light-emitting device 4. 56A and 56B are graphs illustrating the transient EL characteristics of light-emitting device 4. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the form and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0060] (Embodiment 1) Thermally activated delayed fluorescence (TADF) materials are capable of converting triplet excitation energy into light emission, and are therefore attracting attention as highly efficient light-emitting materials that can replace phosphorescent materials in electrically excited light-emitting devices. There is a demand for the development of TADF materials that can achieve high light-emitting efficiency.

[0061] Organic compounds that exhibit TADF properties differ from ordinary organic compounds in that the difference between the lowest singlet excitation level (S1 level) and the lowest triplet excitation level (T1 level) (ΔE ST ) is known to be extremely small. To realize this state, it is necessary that the HOMO and LUMO are distributed so as to be spatially separated within the molecule.

[0062] ΔE of the organic compound according to one embodiment of the present invention ST The organic compound has a very small emission voltage of 0.2 eV or less, preferably 0.1 eV or less, and efficiently exhibits TADF emission. The organic compound of one embodiment of the present invention is represented by the following general formula (G1).

[0063] [ka]

[0064] In the above general formula (G1), R 1 ~R 8 Each of R is independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group. 1 ~R 8 At least one of is a substituted or unsubstituted diarylamino group.

[0065] In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. Note that n is preferably 0 or 1 because it increases the T1 level. Note that when used as an energy donor for a green light-emitting material in a phosphorescent device or an exciton-harvesting fluorescent element, a higher T1 level is required, and from this viewpoint, n is preferably 0. In addition, ΔE ST From the viewpoint of reducing the energy, n is preferably 1.

[0066] A represents a substituted or unsubstituted benzofuropyrimidine skeleton or a substituted or unsubstituted benzothienopyrimidine skeleton. The benzofuropyrimidine skeleton can also be represented by the following general formula (g1). In the following general formula (g1), Q represents an oxygen atom or a sulfur atom.

[0067] [ka]

[0068] In the above general formula (g1), R 11 ~R 16 One of the is a bond and bonds to the nitrogen atom of α or the carbazolyl group in the above general formula (G1), and the rest are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

[0069] In the above general formula (g1), the bond is R 16 In view of ease of synthesis and good stability, it is preferable that the organic compound according to one embodiment of the present invention is an organic compound represented by the following general formula (G2).

[0070] [ka]

[0071] In the above general formula (G2), R 1 ~R 8 Each of R is independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group. 1 ~R 8 At least one of is a substituted or unsubstituted diarylamino group.

[0072] In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4.

[0073] Also, R 11 ~R 15 are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0074] In the above general formulas (G1) and (G2), R 1 ~R 8At least one of the substituted or unsubstituted diarylamino groups is preferably a group represented by the following general formula (g2).

[0075] [ka]

[0076] In the present specification, Ar 1 and Ar 2 each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

[0077] In the above general formulae (G1) and (G2), R 1 ~R 8 It is preferable that one or two of R is a group represented by the above general formula (g2). 3 and R 6 In the above general formulas (G1) and (G2), it is preferable that one or both of R 1 ~R 8 Two of the above are preferably a group represented by general formula (g2). That is, the organic compound of one embodiment of the present invention is preferably an organic compound represented by general formula (G3) below.

[0078] [ka]

[0079] In the above general formula (G3), Ar 3 ~Ar 6 each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

[0080] Also, R 1 , R 2 , R 4 , R 5 , R 7 and R 8each independently represents one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a cycloalkyl group having 3 to 7 carbon atoms.

[0081] In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4.

[0082] Also, R 11 ~R 15 are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0083] In the above general formula (G3), R 1 , R 2 , R 4 , R 5 , R 7 , R 8 , R 11 , R 12 , R 14 and R 15 is preferably hydrogen because the T1 level is high and synthesis is easy. That is, the organic compound of one embodiment of the present invention is preferably an organic compound represented by the following general formula (G4).

[0084] [ka]

[0085] In the above general formula (G4), Ar 3 ~Ar 6 each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

[0086] In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4.

[0087] Also, R 13represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0088] In the organic compounds represented by the above general formulas (G1) to (G4), α is preferably an unsubstituted phenylene group.

[0089] In the organic compounds represented by any of the above general formulas (G1) to (G4), n is preferably 1 or 0 because the T1 level is high, and more preferably n is 0. That is, the organic compound of one embodiment of the present invention is preferably an organic compound represented by the following general formula (G5).

[0090] [ka]

[0091] In the above general formula (G5), Ar 3 ~Ar 6 each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

[0092] Also, R 13 represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring, and Q represents an oxygen atom or a sulfur atom.

[0093] In this specification, specific examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, and hexyl groups. Specific examples of cycloalkyl groups having 3 to 7 carbon atoms include cyclopropyl and cyclohexyl groups. Specific examples of aryl groups having 6 to 13 carbon atoms forming a ring include phenyl, biphenyl, naphthyl, and fluorenyl groups.

[0094] In addition, when the term "substituted or unsubstituted" is used in this specification, in the case where the group has a substituent, the substituent refers to an alkyl group having 1 to 6 carbon atoms or a cycloalkyl group having 3 to 7 carbon atoms.

[0095] The organic compound of one embodiment of the present invention having the above structure has a ΔE ST Since the luminescence wavelength is small and reverse intersystem crossing easily occurs, it is easy to obtain TADF emission, and it is an organic compound that emits light with good efficiency. Furthermore, a light-emitting device using the organic compound can be a light-emitting device that emits light with very good efficiency. Note that, when a transient EL is measured for a light-emitting device using the organic compound of one embodiment of the present invention, a delayed fluorescence component is observed, and the transient lifetime is 100 nanoseconds to 10 milliseconds, preferably 1 microsecond to 10 microseconds.

[0096] Specific examples of organic compounds having the above structure are shown below.

[0097] [ka]

[0098] [ka]

[0099] [ka]

[0100] [ka]

[0101] [ka]

[0102] [ka]

[0103] [ka]

[0104] [ka]

[0105] Next, a method for synthesizing the organic compound represented by the above general formula (G1) will be described. The compound represented by the general formula (G1) can be obtained by coupling an organoboron compound of a carbazole derivative or a boronic acid (compound 1) with a halide or triflate-substituted benzofuropyrimidine derivative or a benzothienopyrimidine derivative (compound 2) by the Suzuki-Miyaura reaction, as shown in the following synthesis scheme. In the following synthesis scheme, R 1 ~R 8 Each of R is independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group. 1 ~R 8 At least one of the groups is a substituted or unsubstituted diarylamino group. In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. In addition, A represents a substituted or unsubstituted benzofuropyrimidine skeleton or a substituted or unsubstituted benzothienopyrimidine skeleton.

[0106] [ka]

[0107] In the above synthesis scheme, X 12 represents a halogen such as chlorine, bromine, or iodine, or a triflate group, and X 12 When is a halogen, chlorine, bromine or iodine is particularly preferred.

[0108] Also, R 50 and R 51 each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms; R 50 and R 51 may be bonded to each other to form a ring.

[0109] Examples of palladium catalysts that can be used in the reactions represented by the above synthesis schemes include palladium(II) acetate, tetrakis(triphenylphosphine)palladium(0), bis(triphenylphosphine)palladium(II) dichloride, and the like.

[0110] Examples of the ligand for the palladium catalyst include di(1-adamantyl)-n-butylphosphine, tri(ortho-tolyl)phosphine, triphenylphosphine, tricyclohexylphosphine, and the like.

[0111] Examples of the base that can be used in the reaction represented by the above synthesis scheme include organic bases such as sodium tert-butoxide, and inorganic bases such as potassium carbonate and sodium carbonate.

[0112] In the reaction represented by the above synthesis scheme, examples of solvents that can be used include a mixed solvent of toluene and water, a mixed solvent of an alcohol such as toluene and ethanol and water, a mixed solvent of xylene and water, a mixed solvent of an alcohol such as xylene and ethanol and water, a mixed solvent of benzene and water, a mixed solvent of an alcohol such as benzene and ethanol and water, a mixed solvent of an ether such as ethylene glycol dimethyl ether and water, a mixed solvent of an ether such as ethylene glycol dimethyl ether and an alcohol such as ethanol, etc. However, the solvents that can be used are not limited to these. In addition, a mixed solvent of toluene and water or a mixed solvent of toluene, ethanol and water, a mixed solvent of an ether such as ethylene glycol dimethyl ether and water, and a mixed solvent of an ether such as ethylene glycol dimethyl ether and an alcohol such as ethanol are more preferred.

[0113] As a coupling reaction that can be used in the above synthesis scheme, a cross-coupling reaction using an organoaluminum, organozirconium, organozinc, organotin compound, etc. may be used instead of the Suzuki-Miyaura coupling reaction using an organoboron compound or boronic acid shown in Compound 1. In addition, in the reaction shown in the above synthesis scheme, an organoboron compound or boronic acid of a benzofuropyrimidine derivative or benzothienopyrimidine derivative and a halide or triflate-substituted carbazole derivative may be coupled by the Suzuki-Miyaura reaction.

[0114] Moreover, the compound represented by the general formula (G1) can also be synthesized by the synthesis method shown in the Examples.

[0115] (Embodiment 2) In this embodiment, a light-emitting device according to one embodiment of the present invention will be described.

[0116] 1A illustrates a light-emitting device according to one embodiment of the present invention. The light-emitting device according to one embodiment of the present invention includes a first electrode 101, a second electrode 102, and an EL layer 103. The EL layer 103 includes the organic compound described in Embodiment 1.

[0117] The EL layer 103 has a light-emitting layer 113, and the light-emitting layer 113 contains a light-emitting material. A hole injection layer 111 and a hole transport layer 112 are provided between the light-emitting layer 113 and the first electrode 101. The organic compound described in the first embodiment is preferably used as the light-emitting material because it efficiently emits light by TADF.

[0118] The light-emitting layer 113 may also include a host material together with the light-emitting material. The host material is an organic compound having carrier transporting properties. The host material may include not only one type, but also multiple types. In this case, it is preferable that the multiple organic compounds are an organic compound having electron transporting properties and an organic compound having hole transporting properties, because it is possible to adjust the carrier balance in the light-emitting layer 113. The multiple organic compounds may both be organic compounds having electron transporting properties (or hole transporting properties), but it is also possible to adjust the carrier transporting properties in the light-emitting layer 113 by making the carrier transporting properties different. By appropriately adjusting the carrier balance, it is possible to provide a light-emitting device with a good lifetime and a light-emitting device with good luminous efficiency. In addition, it is possible to form an exciplex between the multiple organic compounds that are host materials, or between the host material and the light-emitting material. By forming an exciplex having an appropriate emission wavelength, it is possible to realize effective energy transfer to the light-emitting material, and to provide a light-emitting device with high efficiency and good lifetime.

[0119] In addition, when an exciplex is formed between a host material and a light-emitting material and emits light, a device with higher efficiency than a normal fluorescent device (for example, an external quantum efficiency of 7% or more) can be obtained. In this case, delayed fluorescence is also observed from the light-emitting device.

[0120] Note that the organic compound of one embodiment of the present invention has a bipolar property and can be suitably used as a host material of a light-emitting layer. Since the organic compound of one embodiment of the present invention has a TADF property, triplet excitation energy can be converted into singlet excitation energy. The converted singlet excitation energy can be transferred to a fluorescent material to emit light, so that the triplet excitation energy can be converted into light emission. Thus, a fluorescent light-emitting device with very good luminous efficiency can be obtained (so-called exciton-collecting fluorescent element). In addition, since the fluorescent light-emitting material emits light stably, the light-emitting device can easily be made into a light-emitting device with a long life.

[0121] 1A shows the EL layer 103 including the light-emitting layer 113, the hole injection layer 111, the hole transport layer 112, the electron transport layer 114, and the electron injection layer 115, but the configuration of the light-emitting device is not limited to these. Any of these layers may not be formed, or a layer having another function may be included.

[0122] Next, an example of a detailed structure and materials of the above-mentioned light-emitting device will be described. As described above, the light-emitting device according to one embodiment of the present invention has an EL layer 103 composed of multiple layers between a pair of electrodes, the first electrode 101 and the second electrode 102, and any part of the EL layer 103 contains the organic compound disclosed in the first embodiment.

[0123] The first electrode 101 is preferably formed using a metal, alloy, conductive compound, or a mixture thereof having a large work function (specifically, 4.0 eV or more). Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like. As an example of a manufacturing method, indium oxide-zinc oxide may be formed by a sputtering method using a target containing indium oxide and 1 to 20 wt % zinc oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) may also be formed by a sputtering method using a target containing indium oxide and 0.5 to 5 wt % tungsten oxide and 0.1 to 1 wt % zinc oxide. Other examples include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), and nitrides of metal materials (e.g., titanium nitride). Graphene can also be used. By using a composite material described later for the layer in contact with the first electrode 101 in the EL layer 103, it becomes possible to select an electrode material regardless of the work function.

[0124] The EL layer 103 preferably has a laminated structure, but the laminated structure is not particularly limited, and various layer structures such as a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, a carrier block layer, an exciton block layer, and a charge generation layer can be applied. In this embodiment, as an example, two types of structures will be described: a structure having an electron transport layer 114 and an electron injection layer 115 in addition to a hole injection layer 111, a hole transport layer 112, and a light emitting layer 113 as shown in FIG. 1A, and a structure having an electron transport layer 114 and a charge generation layer 116 in addition to a hole injection layer 111, a hole transport layer 112, and a light emitting layer 113 as shown in FIG. 1B. The materials constituting each layer are specifically described below.

[0125] The hole-injection layer 111 is a layer containing a substance having an acceptor property. As the substance having an acceptor property, either an organic compound or an inorganic compound can be used.

[0126] As a substance having acceptor properties, a compound having an electron-withdrawing group (a halogen group or a cyano group) can be used, and 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F 4 -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, etc. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms, such as HAT-CN, are thermally stable and preferable. Radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups or cyano groups)[3] are preferred because they have very high electron-accepting properties, and specific examples include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. Organic compounds with acceptor properties are easy to use because they can be easily evaporated and formed into films.

[0127] As the substance having acceptor properties, in addition to the organic compounds described above, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. can be used.

[0128] In addition, phthalocyanine (abbreviation: H 2 The hole injection layer 111 can also be formed from phthalocyanine complex compounds such as copper phthalocyanine (CuPc) and 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) and N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS). A substance having acceptor properties can extract electrons from an adjacent hole transport layer (or hole transport material) by application of an electric field.

[0129] A composite material in which a material having a hole transporting property contains a substance having an acceptor property can also be used as the hole injection layer 111. By using a composite material in which a material having a hole transporting property contains a substance having an acceptor property, a material for forming an electrode can be selected regardless of the work function. That is, not only a material having a high work function but also a material having a low work function can be used as the first electrode 101.

[0130] As a material having a hole transport property used in the composite material, various organic compounds such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as a material having a hole transport property used in the composite material, a 1×10 -6 cm 2 A material having a hole mobility of 100 / Vs or more is preferable. Specific examples of organic compounds that can be used as a material having a hole transport property in a composite material are listed below.

[0131] Examples of aromatic amine compounds that can be used in the composite material include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B). Specific examples of the carbazole derivative include 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCA3), Examples of compounds that can be used include tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (abbreviation: CzPA), and 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.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- Butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, etc. In addition, pentacene, coronene, etc. can also be used. It may have a vinyl skeleton. Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA).

[0132] In addition, polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used.

[0133] The material having hole transport properties used in the composite material preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the second organic compound may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the second organic compound is a substance having an N,N-bis(4-biphenyl)amino group, because a light-emitting device with a long life can be fabricated. Specific examples of the second organic compound include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8 -yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d] Furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(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)triphenylamine 4,4'-Bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-diphenyl-4'-(2-naphthyl)-4''-{9-(4-biphenylyl)carbazole)}triphenylamine N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(4-biphenylyl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(1,1'-biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)-9,9'-spiro-bi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(dibenzofuran-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4- Phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBASF) :PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-1-amine, etc. can be mentioned.

[0134] Note that the material having a hole-transporting property used in the composite material is more preferably a substance having a relatively deep HOMO level of −5.7 eV or more and −5.4 eV or less. When the material having a hole-transporting property used in the composite material has a relatively deep HOMO level, it becomes easy to inject holes into the hole-transporting layer 112, and it becomes easy to obtain a light-emitting device with a long lifetime.

[0135] The refractive index of the layer can be reduced by further mixing an alkali metal or alkaline earth metal fluoride with the composite material (preferably with an atomic ratio of fluorine atoms of 20% or more in the layer). 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.

[0136] By forming the hole injection layer 111, the hole injection property is improved, and a light emitting device with a low driving voltage can be obtained.

[0137] The hole transport layer 112 is formed by including a material having a hole transport property. -6 cm 2The hole transporting material preferably has a hole mobility of 1000 nm or more. Examples of the hole transporting material include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: B PAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: Aromatic amines such as 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF) Compounds with an amine skeleton, compounds with a carbazole skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compounds include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. The substances given as examples of materials having a hole transport property used in the composite material of the hole injection layer 111 can also be suitably used as materials for the hole transport layer 112. The organic compounds described in embodiment 1 have high hole transport properties and can therefore be very suitably used as materials for the hole transport layer 112. In addition, since the organic compounds described in embodiment 1 have high hole transport properties, even if the hole transport layer 112 is formed to a thickness of 100 nm or more, a light-emitting device can be provided in which the increase in driving voltage is small and the device has good element characteristics. By making the hole transport layer 112 thick, the optical path length between the electrodes can be easily adjusted, which makes it easy to appropriately configure a microcavity structure.

[0138] The light-emitting layer 113 contains a light-emitting substance and a host material. The light-emitting layer 113 may contain other materials at the same time. The light-emitting layer 113 may also be a laminate of two layers having different compositions.

[0139] The light-emitting substance may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or other light-emitting substances, and the organic compound of one embodiment of the present invention can be preferably used. The organic compound of one embodiment of the present invention is a substance that efficiently exhibits TADF.

[0140] Examples of materials that can be used as the fluorescent substance in the light-emitting layer 113 include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl) 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4- phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N'''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N', N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetrahydrofuran N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl N-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-(Pi 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrene diamine compounds, such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they have high hole trapping properties, excellent luminous efficiency, and excellent reliability. Other fluorescent substances can also be used.

[0141] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, examples of materials that can be used include tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp) 3 ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) 3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) 3 Organometallic iridium complexes with a 4H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) 3 ]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) 3 ]), and fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi) 3 ]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me 3 Organometallic iridium complexes with imidazole skeletons such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) picolinate (abbreviation: [Ir(CF 3 ppy) 2 (pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ] Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as FIracac), are examples of such compounds. These are compounds that exhibit blue phosphorescence and have a peak emission wavelength between 440 nm and 520 nm.

[0142] In addition, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) 3 ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 3 ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) 2 (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) 2 (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) 2 (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm) 2 (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) 2 (Acac)]), (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me 2 (acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinate)iridium(III) (abbreviation: [Ir(mppr-iPr) 2 Organometallic iridium complexes with pyrazine skeletons such as tris(2-phenylpyridinato-N,C(acac)]) 2’ ) Iridium(III) (abbreviation: [Ir(ppy) 3 ]), bis(2-phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy) 2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq) 2 (acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq) 3 ]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq) 3 ]), bis(2-phenylquinolinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(pq) 2 (acac)]), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κ]iridium(III) (abbreviation: [Ir(5mppy-d3) 2 (mbfpypy-d3)]), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) 2 In addition to organometallic iridium complexes with pyridine skeletons such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) 3 These are compounds that mainly exhibit green phosphorescence, with the emission wavelength peak at 500 nm to 600 nm. Organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0143] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) 2 (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) 2(dpm)]), bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm) 2 Organometallic iridium complexes with pyrimidine skeletons such as (acetylacetonato)bis(2,3,5-triphenylpyrazinate)iridium(III) (abbreviation: [Ir(tppr) 2 (acac)]), bis(2,3,5-triphenylpyrazinate)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr) 2 (dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) 2 Organometallic iridium complexes with pyrazine skeletons such as tris(1-phenylisoquinolinato-N,C(acac)]) 2’ ) Iridium(III) (abbreviation: [Ir(piq) 3 ]), bis(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(piq) 2 In addition to organometallic iridium complexes with pyridine skeletons such as iridium complexes with pyridine skeletons such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), platinum complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM) 3 (Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) 3 These are compounds that exhibit red phosphorescence, with emission peaks at 600 nm to 700 nm. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity.

[0144] In addition to the phosphorescent materials described above, known phosphorescent materials may be selected and used.

[0145] As a substance exhibiting TADF (TADF material), fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. can be used. As the metal-containing porphyrin, for example, protoporphyrin-tin fluoride complex (SnF) represented by the following structural formula can be used. 2 (Proto IX)), mesoporphyrin-tin fluoride complex (SnF 2 (Meso IX)), hematoporphyrin-tin fluoride complex (SnF 2 (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF 2 (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF 2 (OEP)), etioporphyrin-tin fluoride complex (SnF 2 (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl 2 Note that the organic compound of one embodiment of the present invention is also a TADF material.

[0146] [ka]

[0147] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), Heterocyclic compounds having one or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and the triazine skeleton are preferred because they are stable and reliable. In particular, the benzofuropyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuropyrazine skeleton, and the benzothienopyrazine skeleton are preferred because they have high acceptor properties and good reliability. In addition, among the skeletons having a π-electron rich heteroaromatic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton, and the pyrrole skeleton are preferred because they are stable and reliable.As the furan skeleton, a dibenzofuran skeleton is preferable, and as the thiophene skeleton, a dibenzothiophene skeleton is preferable. As the pyrrole skeleton, an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because the electron donating property of the π-electron-rich heteroaromatic ring and the electron accepting property of the π-electron-deficient heteroaromatic ring are both strong, and the energy difference between the S1 level and the T1 level is small, so that TADF can be efficiently obtained. 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. In addition, an aromatic amine skeleton, a phenazine skeleton, or the like can be used as the π-electron-rich skeleton. In addition, examples of the π-electron-deficient skeleton that can be used include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring or a heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0148] [ka]

[0149] In addition, TADF materials are characterized by the difference between the S1 level and the T1 level (ΔE ST ) and has the function of converting energy from triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy by a small amount of thermal energy (reverse intersystem crossing), and the singlet excited state can be generated efficiently. In addition, triplet excitation energy can be converted into light emission.

[0150] In addition, an excited complex (also called an exciplex) that forms an excited state with two types of substances has a ΔE ST It functions as a TADF material that has an extremely small molecular weight and can convert triplet excitation energy into singlet excitation energy.

[0151] As an index of the T1 level, a phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K) may be used. When a tangent line is drawn at the short wavelength side of the fluorescent spectrum of a TADF material, and the energy of the wavelength of the extrapolated line is defined as the S1 level, and a tangent line is drawn at the short wavelength side of the phosphorescence spectrum of a TADF material, and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between the S1 level and the T1 level is preferably 0.3 eV or less, more preferably 0.2 eV or less, and even more preferably 0.1 eV or less.

[0152] In addition, when a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0153] As a host material for the light-emitting layer, various carrier transporting materials such as a material having an electron transporting property, a material having a hole transporting property, the above-mentioned TADF material, etc. Note that the organic compound of one embodiment of the present invention also has a bipolar property and can therefore be suitably used as a host material.

[0154] As a material having hole transport properties, an organic compound having an amine skeleton or a π-electron-rich heteroaromatic ring skeleton is preferable. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP ... mBPAFLP, 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (PCBANB) ), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF) and other aromatic amine skeletons compounds having a carbazole skeleton such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP); 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II);Examples of the compounds include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transport properties, and contribute to reducing the driving voltage.

[0155] An example of a material having electron transport properties is bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq 2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and other metal complexes, and organic compounds having a π-electron-deficient heteroaromatic ring skeleton are preferred.Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1 Heterocyclic compounds having a polyazole skeleton such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]kyi, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]kyi, and ... quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl )phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzo[h]quinazoline (abbreviation: 4,8mDBtP2Bqn), and other heterocyclic compounds having a diazine skeleton, and heterocyclic compounds having a pyridine skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and other heterocyclic compounds having a pyridine skeleton. Among the above, heterocyclic compounds having a diazine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their good reliability.In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0156] As a TADF material that can be used as a host material, the same TADF materials listed above can be used. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy by reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby increasing the light-emitting 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.

[0157] This is very effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0158] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest energy absorption band of the fluorescent material, because this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0159] In addition, in order to efficiently generate singlet excitation energy from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. In addition, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. For this purpose, it is preferable that the fluorescent material has a protective group around the luminophore (skeleton causing light emission) of the fluorescent material. As the protective group, a substituent having no π bond is preferable, and a saturated hydrocarbon is preferable, specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms are mentioned, and it is more preferable that there are a plurality of protective groups. Since a substituent having no π bond has poor function of transporting carriers, the distance between the TADF material and the luminophore of the fluorescent material can be increased without affecting carrier transport or carrier recombination. Here, the luminophore refers to an atomic group (skeleton) causing light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, and a phenothiazine skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because they have a high fluorescence quantum yield.

[0160] When a fluorescent emitting material is used as the emitting material, a material having an anthracene skeleton is suitable as the host material. When a material having an anthracene skeleton is used as the host material of the fluorescent emitting material, it is possible to realize an emitting layer having both good luminous efficiency and durability. As a material having an anthracene skeleton to be used as the host material, a material having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferable because it is chemically stable. In addition, when the host material has a carbazole skeleton, it is preferable because the injection and transport properties of holes are improved, but when the host material contains a benzocarbazole skeleton in which a benzene ring is further condensed to carbazole, the HOMO is shallower by about 0.1 eV than that of carbazole, making it easier for holes to enter, which is more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, it is preferable because the HOMO is shallower by about 0.1 eV than that of 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 material having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). From the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such a material include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: CzPA), and 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: CzPA). Examples of such compounds include carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), and 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth).In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices since they exhibit very good properties.

[0161] The host material may be a mixture of a plurality of substances. When a mixture of host materials is used, it is preferable to mix a material having an electron transporting property with a material having a hole transporting property. By mixing a material having an electron transporting property with a material having a hole transporting property, the transporting property of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The weight ratio of the content of the material having a hole transporting property to the material having an electron transporting property may be 1:19 to 19:1 (material having a hole transporting property: material having an electron transporting property). As the material having an electron transporting property in the mixed host material, the organic compound described in embodiment 1 can be preferably used.

[0162] A phosphorescent material can be used as a part of the mixed material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as a light-emitting material.

[0163] In addition, these mixed materials may form an exciplex. It is preferable to select a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest energy absorption band of the light-emitting material, because this makes energy transfer smooth and allows efficient light emission. In addition, the use of this structure is preferable because the driving voltage is reduced.

[0164] At least one of the materials forming the exciplex may be a phosphorescent material, which allows the triplet excitation energy to be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0165] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transport properties is equal to or higher than the HOMO level of the material having electron transport properties. It is also preferable that the LUMO level of the material having hole transport properties is equal to or higher than the LUMO level of the material having electron transport properties. The LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0166] The formation of an exciplex can be confirmed, for example, by comparing the emission spectrum of a material having hole transport properties, the emission spectrum of a material having electron transport properties, and the emission spectrum of a mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectrum of each material (or has a new peak on the longer wavelength side). Alternatively, the formation of an exciplex can be confirmed by comparing the transient photoluminescence (PL) of a material having hole transport properties, the transient PL of a material having electron transport properties, and the transient PL of a mixed film obtained by mixing these materials, and observing the difference in transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component than the transient PL lifetime of each material, or the proportion of delayed components becoming larger. The above-mentioned transient PL may also be read as transient electroluminescence (EL). That is, the formation of an exciplex can also be confirmed by comparing the transient EL of a material having hole transport properties, the transient EL of a material having electron transport properties, and the transient EL of a mixed film obtained by mixing these materials, and observing the difference in transient response.

[0167] The electron transport layer 114 is a layer containing a substance having an electron transport property. As the substance having an electron transport property, any of the substances exemplified above as the substance having an electron transport property that can be used as the host material can be used.

[0168] The electron transport layer 114 has an electron mobility of 1×10 -7 cm 2 / Vs or more 5×10 -5 cm 2 / Vs or less. By lowering the electron transportability in the electron transport layer 114, the amount of electrons injected into the light-emitting layer can be controlled, and the light-emitting layer can be prevented from becoming in an electron excess state. In addition, the electron transport layer preferably contains a material having an electron transportability and an alkali metal or an element, compound, or complex of an alkali metal. These configurations are particularly preferable when the hole injection layer is formed as a composite material, and the HOMO level of the material having hole transportability in the composite material is a substance having a relatively deep HOMO level of -5.7 eV or more and -5.4 eV or less, because the lifetime is improved. In this case, the material having electron transportability preferably has a HOMO level of -6.0 eV or more. In addition, the material having electron transportability is preferably an organic compound having an anthracene skeleton, and more preferably an organic compound having both an anthracene skeleton and a heterocyclic skeleton. The heterocyclic skeleton is preferably a nitrogen-containing 5-membered skeleton or a nitrogen-containing 6-membered skeleton, and particularly preferably has a nitrogen-containing 5-membered skeleton or a nitrogen-containing 6-membered skeleton containing two heteroatoms in the ring, such as a pyrazole ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyrazine ring, a pyrimidine ring, or a pyridazine ring. In addition, the alkali metal or alkali metal simple substance, compound, or complex preferably contains an 8-hydroxyquinolinato structure. Specifically, for example, 8-hydroxyquinolinato-lithium (abbreviation: Liq) and 8-hydroxyquinolinato-sodium (abbreviation: Naq) can be mentioned. In particular, a complex of a monovalent metal ion, particularly a lithium complex, is preferable, and Liq is more preferable. In addition, when the 8-hydroxyquinolinato structure is contained, a methyl-substituted product (for example, a 2-methyl-substituted product or a 5-methyl-substituted product) can also be used. In the electron transport layer, it is preferable that the alkali metal or the simple substance, compound or complex of the alkali metal has a concentration difference (including the case where the concentration difference is 0) in the thickness direction.

[0169] Between the electron transport layer 114 and the second electrode 102, an electron injection layer 115 made of lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF 2Alternatively, a layer containing an alkali metal or alkaline earth metal, such as lithium 8-hydroxyquinolinato (abbreviation: Liq), or a compound thereof may be provided. The electron injection layer 115 may be a layer made of a substance having an electron transporting property containing an alkali metal or alkaline earth metal, or a compound thereof, or an electride. Examples of the electride include a substance in which electrons are added at a high concentration to a mixed oxide of calcium and aluminum.

[0170] Note that a layer containing a fluoride of the alkali metal or alkaline earth metal in a substance having an electron transporting property (preferably an organic compound having a bipyridine skeleton) at a concentration at which the fluoride is in a microcrystalline state or higher (50 wt % or higher) can be used as the electron injection layer 115. Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0171] Alternatively, a charge generation layer 116 may be provided instead of the electron injection layer 115 (FIG. 1B). The charge generation layer 116 is a layer capable of injecting holes into a layer in contact with the cathode side of the layer and electrons into a layer in contact with the anode side of the layer by applying a potential. The charge generation layer 116 includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material listed above as a material capable of forming the hole injection layer 111. The P-type layer 117 may also be formed by laminating a film containing an acceptor material and a film containing a hole transport material, both of which are materials that 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.

[0172] It is preferable that the charge generating layer 116 is provided with either or both of an electron relay layer 118 and an electron injection buffer layer 119 in addition to the P-type layer 117 .

[0173] The electron relay layer 118 contains at least a substance having an electron transporting property, and has a function of preventing an interaction between the electron injection buffer layer 119 and the P-type layer 117 and smoothly transferring electrons. The LUMO level of the substance having an electron transporting property contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor substance in the P-type layer 117 and the LUMO level of the substance contained in the layer in contact with the charge generating layer 116 in the electron transport layer 114. The specific energy level of the LUMO level of the substance having an electron transporting property used in the electron relay layer 118 is -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. Note that, as the substance having an electron transporting property used in the electron relay layer 118, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0174] The electron injection buffer layer 119 can be made of a material with high electron injection properties, such as an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (an alkali metal compound (including an oxide such as lithium oxide, a halide, or a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, or a carbonate), or a rare earth metal compound (including an oxide, a halide, or a carbonate)).

[0175] In addition, when the electron-injection buffer layer 119 is formed containing a substance having an electron-transporting property and a donor substance, as the donor substance, an alkali metal, an alkaline earth metal, a rare earth metal, and a compound thereof (an alkali metal compound (including an oxide such as lithium oxide, a halide, or a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, or a carbonate), or a rare earth metal compound (including an oxide, a halide, or a carbonate)), or an organic compound such as tetrathianaphthacene (abbreviation: TTN), nickelocene, or decamethylnickelocene can be used. Note that as the substance having an electron-transporting property, a material similar to the material constituting the electron-transporting layer 114 described above can be used.

[0176] The second electrode 102 may be made of a metal, alloy, electrically conductive compound, or mixture thereof having a small work function (specifically, 3.8 eV or less). Specific examples of such a cathode material include alkali metals such as lithium (Li) and cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these elements (MgAg, AlLi), rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these elements. 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, and indium oxide-tin oxide containing silicon or silicon oxide can be used as the second electrode 102 regardless of the magnitude of the work function. These conductive materials can be formed into films using dry methods such as vacuum deposition and sputtering, inkjet methods, spin coating methods, and the like. Also, it may be formed by a wet method using a sol-gel method, or may be formed by a wet method using a paste of a metal material.

[0177] In addition, various methods, whether dry or wet, can be used to form the EL layer 103. For example, a vacuum deposition method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method (a droplet ejection method), a spin coating method, or the like may be used.

[0178] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0179] The configuration of the layers provided between the first electrode 101 and the second electrode 102 is not limited to the above. However, a configuration in which a light-emitting region where holes and electrons recombine is provided at a position away from the first electrode 101 and the second electrode 102 is preferable so as to suppress quenching caused by the proximity of the light-emitting region to the metals used in the electrodes and the carrier injection layer.

[0180] In addition, the hole transport layer and electron transport layer in contact with the light-emitting layer 113, particularly the carrier transport layer close to the recombination region in the light-emitting layer 113, are preferably composed of a material having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer, in order to suppress energy transfer from excitons generated in the light-emitting layer.

[0181] Here, a method for forming the EL layer 786 by a droplet discharge method will be described with reference to Fig. 2. Fig. 2A to Fig. 2D are cross-sectional views illustrating a method for manufacturing the EL layer 786.

[0182] First, a conductive film 772 is formed over a planarization insulating film 770, and an insulating film 730 is formed so as to cover part of the conductive film 772 (see FIG. 2A).

[0183] Next, droplets 784 are discharged from a droplet discharge device 783 to an exposed portion of the conductive film 772, which is an opening in the insulating film 730, to form a layer 785 containing a composition. The droplets 784 are a composition containing a solvent, and are attached onto the conductive film 772 (see FIG. 2B).

[0184] The step of discharging the droplets 784 may be performed under reduced pressure.

[0185] Next, the solvent is removed from the layer 785 containing the composition, and the layer is solidified to form an EL layer 786 (see FIG. 2C).

[0186] The solvent may be removed by a drying step or a heating step.

[0187] Next, a conductive film 788 is formed over the EL layer 786 to form the light emitting device 782 (see FIG. 2D).

[0188] When the EL layer 786 containing a light-emitting substance is formed by the droplet discharge method in this way, the composition can be discharged selectively, so that the loss of material can be reduced. In addition, since a lithography process for processing the shape is not required, the process can be simplified, and the cost can be reduced.

[0189] The droplet discharge method described above is a general term for any method having means for discharging droplets, such as a nozzle having a composition discharge port or a head having one or a plurality of nozzles.

[0190] Next, a droplet discharge device used in the droplet discharge method will be described with reference to Fig. 3. Fig. 3 is a conceptual diagram illustrating a droplet discharge device 1400.

[0191] The droplet discharge device 1400 has a droplet discharge means 1403. The droplet discharge means 1403 also has a head 1405, a head 1412, and a head 1416.

[0192] Head 1405, head 1412, and head 1416 are connected to control means 1407, which can be controlled by computer 1410 to draw a preprogrammed pattern.

[0193] The timing of drawing may be determined based on, for example, a marker 1411 formed on the substrate 1402. Alternatively, a reference point may be determined based on the outer edge of the substrate 1402. Here, the marker 1411 is detected by the imaging means 1404, and converted into a digital signal by the image processing means 1409. The digital signal is recognized by the computer 1410, which generates a control signal and sends it to the control means 1407.

[0194] The imaging means 1404 may be an image sensor using a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS). Information on the pattern to be formed on the substrate 1402 is stored in a storage medium 1408, and based on this information, a control signal is sent to a control means 1407, which can individually control the heads 1405, 1412, and 1416 of the droplet ejection means 1403. The material to be ejected is supplied to the heads 1405, 1412, and 1416 from material supply sources 1413, 1414, and 1415 through pipes, respectively.

[0195] The inside of the head 1405, head 1412, and head 1416 has a structure having a space filled with a liquid material and a nozzle which is an ejection port, as shown by the dotted line 1406. Although not shown, the head 1412 and head 1416 have the same internal structure as the head 1405. If the nozzles of the head 1405, head 1412, and head 1416 are provided with different sizes, different materials can be drawn simultaneously with different widths. A single head can eject and draw multiple types of light-emitting materials, and when drawing in a wide area, the same material can be ejected simultaneously from multiple nozzles to improve throughput. When a large substrate is used, the head 1405, head 1412, and head 1416 can freely scan the substrate in the directions of the X, Y, and Z arrows shown in FIG. 3, and the drawing area can be freely set, and the same pattern can be drawn multiple times on one substrate.

[0196] The step of discharging the composition may be carried out under reduced pressure. The substrate may be heated during discharging. After discharging the composition, one or both of the steps of drying and baking are carried out. Both the drying and baking steps are heat treatment steps, but they differ in purpose, temperature, and time. The drying and baking steps are carried out under normal pressure or reduced pressure by irradiation with laser light, instantaneous thermal annealing, or a heating furnace. The timing of carrying out this heat treatment and the number of times of heat treatment are not particularly limited. In order to carry out the drying and baking steps well, the temperature at that time depends on the material of the substrate and the properties of the composition.

[0197] As described above, the EL layer 786 can be manufactured using a droplet discharge apparatus.

[0198] In the case of preparing the EL layer 786 using a droplet discharge device, when forming the composition by a wet method in which various organic materials or organic-inorganic halogen perovskites are dissolved or dispersed in a solvent, various organic solvents can be used to prepare a coating composition. As the organic solvent that can be used in the composition, various organic solvents such as benzene, toluene, xylene, mesitylene, tetrahydrofuran, dioxane, ethanol, methanol, n-propanol, isopropanol, n-butanol, t-butanol, acetonitrile, dimethylsulfoxide, dimethylformamide, chloroform, methylene chloride, carbon tetrachloride, ethyl acetate, hexane, and cyclohexane can be used. In particular, it is preferable to use a low-polarity benzene derivative such as benzene, toluene, xylene, or mesitylene, because it is possible to prepare a solution of a suitable concentration and to prevent the materials contained in the ink from deteriorating due to oxidation or the like. In addition, in consideration of the uniformity of the film after preparation and the uniformity of the film thickness, it is preferable that the boiling point is 100° C. or higher, and toluene, xylene, and mesitylene are more preferable.

[0199] The above-mentioned structure can be appropriately combined with other embodiments or other structures in this embodiment. Although a method of forming the EL layer 786 as a single layer is shown in Fig. 2 and Fig. 3, it may be formed by laminating a plurality of layers. In this case, the layers may be laminated by performing a wet method such as a droplet discharge method several times, or may be laminated in combination with a vapor deposition method. It is preferable to form the hole injection (transport) layer to the light-emitting layer by a wet method such as a droplet discharge method, and to form the electron transport layer to the cathode by a dry method such as a vapor deposition method or a sputtering method.

[0200] Next, an embodiment of a light-emitting device having a configuration in which a plurality of light-emitting units are stacked (also called a stacked element or a tandem element) will be described with reference to FIG. 1C. This light-emitting device has a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has a configuration almost similar to that of the EL layer 103 shown in FIG. 1A. In other words, it can be said that the light-emitting device shown in FIG. 1C is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1A or FIG. 1B is a light-emitting device having one light-emitting unit.

[0201] In Fig. 1C, a first light-emitting unit 511 and a second light-emitting unit 512 are laminated between an anode 501 and a 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 Fig. 1A, respectively, and the same electrodes as those described in the description of Fig. 1A can be applied. In addition, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same configuration or different configurations.

[0202] Charge generation layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied between anode 501 and cathode 502. That is, when a voltage is applied so that the potential of the anode is higher than the potential of the cathode in FIG. 1C, charge generation layer 513 only needs to inject electrons into first light-emitting unit 511 and inject holes into second light-emitting unit 512.

[0203] The charge generation layer 513 is preferably formed in the same structure as the charge generation layer 116 described in FIG. 1B. A composite material of an organic compound and a metal oxide has excellent carrier injection and carrier transport properties, and therefore can realize low-voltage driving and low-current driving. When the anode side surface of the light-emitting unit is in contact with the charge generation layer 513, the charge generation layer 513 can also play the role of the hole injection layer of the light-emitting unit, so that the light-emitting unit does not need to be provided with a hole injection layer.

[0204] 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 light-emitting unit on the anode side, so that it is not necessarily necessary to form an electron injection layer in the light-emitting unit on the anode side.

[0205] Although the light-emitting device having two light-emitting units has been described in Fig. 1C, the present invention can be applied to a light-emitting device having three or more light-emitting units stacked in the same manner. By disposing a plurality of light-emitting units between a pair of electrodes and separating them with a charge generating layer 513 as in the light-emitting device according to the present embodiment, it is possible to realize an element that can emit light with high brightness while keeping the current density low and has a long life. In addition, it is possible to realize a light-emitting device that can be driven at a low voltage and consumes low power.

[0206] In addition, by making the emission colors of the respective light-emitting units different, it is possible to obtain light emission of a desired color from the light-emitting device as a whole. 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 emission colors from the first light-emitting unit and blue emission color from the second light-emitting unit.

[0207] In addition, each layer and electrode such as the above-mentioned EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer can be formed by using, for example, a deposition method (including a vacuum deposition method), a droplet discharge method (also called an ink-jet method), a coating method, a gravure printing method, etc. In addition, they may contain a low molecular weight material, a medium molecular weight material (including an oligomer and a dendrimer), or a polymer material.

[0208] (Embodiment 3) In this embodiment, a light emitting apparatus using the light emitting device described in Embodiment 2 will be described.

[0209] In this embodiment, a light-emitting device manufactured using the light-emitting device described in embodiment 2 will be described with reference to FIG. 4. FIG. 4A is a top view showing the light-emitting device, and FIG. 4B is a cross-sectional view taken along the lines AB and CD in FIG. 4A. This light-emitting device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, for controlling the light emission of the light-emitting device. Reference numeral 604 denotes a sealing substrate, 605 denotes a sealant, and the inside surrounded by the sealant 605 defines a space 607.

[0210] The lead wiring 608 is a wiring for transmitting signals input to the source line driving circuit 601 and the gate line driving circuit 603, and receives a video signal, a clock signal, a start signal, a reset signal, and the like from an FPC (flexible printed circuit) 609 serving as an external input terminal. Although only an FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. In this specification, the light emitting device includes not only the light emitting device itself, but also a state in which an FPC or a PWB is attached to it.

[0211] Next, the cross-sectional structure will be described with reference to Fig. 4B. A driver circuit section and a pixel section are formed on an element substrate 610, but here, a source line driver circuit 601, which is the driver circuit section, and one pixel in a pixel section 602 are shown.

[0212] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl fluoride), polyester, acrylic resin, or the like.

[0213] The structure of the transistors used in the pixels and the driver circuits is not particularly limited. For example, the transistors may be inverted staggered transistors or staggered transistors. Furthermore, the transistors may be top-gate transistors or bottom-gate transistors. The semiconductor material used in the transistors is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, or the like may be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used.

[0214] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in a part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0215] Here, in addition to the transistors provided in the pixels and the driver circuits, an oxide semiconductor is preferably used for a semiconductor device such as a transistor used in a touch sensor or the like, which will be described later. In particular, an oxide semiconductor having a wider band gap than silicon is preferably used. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0216] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0217] In particular, it is preferable to use, as the semiconductor layer, an oxide semiconductor film having a plurality of crystal parts whose c-axes are oriented perpendicular to a surface on which the semiconductor layer is formed or a top surface of the semiconductor layer and which has no grain boundaries between adjacent crystal parts.

[0218] By using such a material for the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0219] In addition, the transistor having the above-mentioned semiconductor layer can hold charge accumulated in a capacitance through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop a driver circuit while maintaining the gray level of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

[0220] It is preferable to provide an undercoat film in order to stabilize the characteristics of the transistor. The undercoat film can be prepared as a single layer or a multilayer structure using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The undercoat film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, or a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, or the like. Note that the undercoat film need not be provided if it is not necessary.

[0221] The FET 623 indicates one of the transistors formed in the driving circuit section 601. The driving circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. Although the present embodiment shows a driver-integrated type in which a driving circuit is formed on a substrate, this is not necessarily required, and the driving circuit may be formed externally instead of on the substrate.

[0222] In addition, the pixel portion 602 is formed by a plurality of pixels including a switching FET 611, a current control FET 612, and a first electrode 613 electrically connected to the drain of the FET 612. However, the present invention is not limited to this, and the pixel portion may be formed by combining three or more FETs and a capacitive element.

[0223] An insulator 614 is formed to cover an end portion of the first electrode 613. Here, the insulator 614 can be formed by using a positive type photosensitive acrylic resin film.

[0224] In order to improve the covering ability of an EL layer or the like to be formed later, a curved surface having a curvature is formed at the upper end or lower end of the insulator 614. For example, when a positive type photosensitive acrylic resin is used as the material of the insulator 614, it is preferable that only the upper end of the insulator 614 has a curved surface having a radius of curvature (0.2 μm to 3 μm). In addition, either a negative type photosensitive resin or a positive type photosensitive resin can be used as the insulator 614.

[0225] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, it is desirable to use a material with a large work function as a material used for the first electrode 613 that functions as an anode. For example, in addition to a single layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt % zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film, a laminated structure of a titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film, can be used. Note that a laminated structure provides low resistance as wiring, good ohmic contact, and can further function as an anode.

[0226] The EL layer 616 is formed by various methods such as a deposition method using a deposition mask, an inkjet method, a spin coating method, etc. Other materials constituting the EL layer 616 may be low molecular weight compounds or high molecular weight compounds (including oligomers and dendrimers).

[0227] Furthermore, the second electrode 617 formed on the EL layer 616 and functioning as a cathode is preferably made of a material having a small work function (such as Al, Mg, Li, Ca, or an alloy or compound thereof (MgAg, MgIn, AlLi, etc.)). When light generated in the EL layer 616 is transmitted through the second electrode 617, the second electrode 617 is preferably made of a laminate of a thin metal thin film and a transparent conductive film (such as ITO, indium oxide containing 2 to 20 wt % zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.).

[0228] Note that a light-emitting device 618 is formed by the first electrode 613, the EL layer 616, and the second electrode 617. The light-emitting device is the light-emitting device described in Embodiment 2. Note that a pixel portion is formed with a plurality of light-emitting devices, but the light-emitting device in this embodiment may include both the light-emitting device described in Embodiment 2 and light-emitting devices having other structures.

[0229] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealant 605, a structure is formed in which a light emitting device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. The space 607 is filled with a filler, and may be filled with an inert gas (nitrogen, argon, etc.) or a sealant. A recess is formed in the sealing substrate, and a desiccant is provided therein to suppress deterioration due to the influence of moisture, which is a preferable configuration.

[0230] It is preferable to use epoxy resin or glass frit for the sealant 605. It is also preferable that these materials are as moisture and oxygen impermeable as possible. In addition to a glass substrate or a quartz substrate, the sealing substrate 604 may be made of a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like.

[0231] Although not shown in FIG. 4, 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. The protective film may be formed so as to cover the exposed portion of the sealant 605. The protective film may be provided so as to cover the surfaces and side surfaces of the pair of substrates, the exposed side surfaces of the sealing layer, the insulating layer, etc.

[0232] The protective film can be made of a material that is difficult for impurities such as water to permeate, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0233] Examples of materials that can be used to form the protective film include oxides, nitrides, fluorides, sulfides, ternary compounds, metals, and 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, materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, materials 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, and oxides containing yttrium and zirconium can be used.

[0234] The protective film is preferably formed using a film formation method with good step coverage. One such method is the atomic layer deposition (ALD) method. It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. In addition, it is possible to reduce damage to the processed member when forming the protective film.

[0235] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on a surface having a complex uneven shape, as well as on the top surface, side surface, and back surface of a touch panel.

[0236] In the above manner, a light-emitting device manufactured using the light-emitting device described in Embodiment 2 can be obtained.

[0237] A light-emitting device with favorable characteristics can be obtained in the light-emitting device of this embodiment because the light-emitting device described in Embodiment 2 is used. Specifically, since the light-emitting device described in Embodiment 2 has favorable emission efficiency, it is possible to provide a light-emitting device with low power consumption.

[0238] Fig. 5 shows an example of a full-color light-emitting device in which a light-emitting device that emits white light is formed and a colored layer (color filter) is provided, etc. Fig. 5A shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral section 1042, a pixel section 1040, a driving circuit section 1041, first electrodes 1024W, 1024R, 1024G, 1024B of the light-emitting device, a partition wall 1025, an EL layer 1028, a second electrode 1029 of the light-emitting device, a sealing substrate 1031, a sealant 1032, etc.

[0239] In FIG. 5A, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) are provided on a transparent base material 1033. A black matrix 1035 may be further provided. The transparent base material 1033 on which the colored layers and black matrix are provided is aligned and fixed to the substrate 1001. The colored layers and black matrix 1035 are covered with an overcoat layer 1036. In FIG. 5A, there are light-emitting layers from which light does not pass through the colored layers and goes out, and light-emitting layers from which light passes through the colored layers of each color and goes out. The light that does not pass through the colored layers is white, and the light that passes through the colored layers is red, green, and blue, so that an image can be expressed by four color pixels.

[0240] 5B shows an example in which the 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. In this manner, the colored layers may be provided between the substrate 1001 and the sealing substrate 1031.

[0241] In the light-emitting device described above, the light-emitting device has a structure (bottom emission type) in which light is extracted to the substrate 1001 side on which the FET is formed, but the light-emitting device may have a structure (top emission type) in which light is extracted to the sealing substrate 1031 side. A cross-sectional view of a top emission type light-emitting device is shown in FIG. 6. In this case, a substrate that does not transmit light can be used as the substrate 1001. The process is performed in the same manner as the bottom emission type light-emitting device until a connection electrode that connects the FET and the anode of the light-emitting device is formed. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may play a role of planarization. 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.

[0242] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are anodes here, but may be cathodes. In addition, in the case of a top-emission type light-emitting device as shown in FIG. 6, it is preferable that the first electrodes are reflective electrodes. The EL layer 1028 has the same configuration as that described for the EL layer 103 in the second embodiment, and has an element structure that can emit white light.

[0243] In the top emission structure as shown in FIG. 6, sealing can be performed with a sealing substrate 1031 provided with colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) and the black matrix may be covered with an overcoat layer 1036. Note that a substrate having light transmissivity is used as the sealing substrate 1031. In addition, although an example of full color display using four colors, red, green, blue, and white, is shown here, the present invention is not particularly limited, and full color display using four colors, red, yellow, green, and blue, or three colors, red, green, and blue, may be used.

[0244] In a top-emission type light-emitting device, a microcavity structure can be suitably applied. 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 / semi-reflective electrode. At least an EL layer is provided between the reflective electrode and the semi-transmissive / semi-reflective electrode, and at least a light-emitting layer that becomes a light-emitting region is provided.

[0245] The reflectance of the reflective electrode to visible light is 40% to 100%, preferably 70% to 100%, and the resistivity is 1×10 -2 The semi-transmitting and semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1×10 -2 It is assumed that the film has a resistance of less than Ωcm.

[0246] Light emitted from a light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transmissive and semi-reflective electrode, causing resonance.

[0247] In this light-emitting device, the optical distance between the reflective electrode and the semi-transmissive / semi-reflective electrode can be changed by changing the thickness of the transparent conductive film, the above-mentioned composite material, the carrier transport material, etc. This makes it possible to intensify the light of a resonating wavelength between the reflective electrode and the semi-transmissive / semi-reflective electrode and attenuate the light of a non-resonating wavelength.

[0248] In addition, since the light reflected by the reflective electrode and returned (first reflected light) causes significant interference with the light (first incident light) that is directly incident on the semi-transmissive and semi-reflective electrode from the light-emitting layer, it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number equal to or greater than 1, and λ is the wavelength of the emitted light to be amplified). By adjusting the optical distance, the phase of the first reflected light and the first incident light can be aligned, thereby further amplifying the light emitted from the light-emitting layer.

[0249] In the above configuration, the EL layer may have a structure having multiple light-emitting layers or a structure having a single light-emitting layer. For example, the EL layer may be combined with the above-mentioned tandem light-emitting device configuration, in which multiple EL layers are provided in one light-emitting device with a charge generation layer sandwiched therebetween, and a single or multiple light-emitting layers are formed in each EL layer.

[0250] The microcavity structure makes it possible to increase the emission intensity of a specific wavelength in the front direction, thereby reducing power consumption. In the case of a light-emitting device that displays images using four sub-pixels of red, yellow, green, and blue, in addition to the brightness improvement effect of yellow emission, the microcavity structure that matches the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with good characteristics.

[0251] A light-emitting device with favorable characteristics can be obtained in the light-emitting device of this embodiment because the light-emitting device described in Embodiment 2 is used. Specifically, since the light-emitting device described in Embodiment 2 has favorable emission efficiency, it is possible to provide a light-emitting device with low power consumption.

[0252] Up to this point, active matrix type light emitting devices have been described, but from here on, passive matrix type light emitting devices will be described. FIG. 7 shows a passive matrix type light emitting device manufactured by applying the present invention. FIG. 7A is a perspective view showing the light emitting device, and FIG. 7B is a cross-sectional view taken along XY in FIG. 7A. In FIG. 7, an EL layer 955 is provided between an electrode 952 and an electrode 956 on a substrate 951. An end of the electrode 952 is 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 an inclination such that the distance between one side wall and the other side wall becomes narrower as the side walls approach the substrate surface. That is, the cross section of the partition layer 954 in the short side direction is trapezoidal, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the top side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this manner, defects in the light-emitting device due to static electricity or the like can be prevented. In addition, the light-emitting device described in Embodiment 2 is used in a passive matrix light-emitting device, and the light-emitting device can be made to be highly reliable or to have low power consumption.

[0253] The light emitting device described above is capable of individually controlling a large number of minute light emitting devices arranged in a matrix, and is therefore a light emitting device that can be suitably used as a display device for displaying images.

[0254] This embodiment mode can be freely combined with other embodiment modes.

[0255] (Embodiment 4) In this embodiment, an example in which the light-emitting device described in Embodiment 2 is used as a lighting device will be described with reference to Fig. 8. Fig. 8B is a top view of the lighting device, and Fig. 8A is a cross-sectional view taken along line ef in Fig. 8B.

[0256] In the lighting device in this embodiment, a first electrode 401 is formed over a light-transmitting substrate 400, which is 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 using a light-transmitting material.

[0257] A pad 412 for supplying a voltage to the second electrode 404 is formed on the substrate 400 .

[0258] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the structure of the EL layer 103 in Embodiment 2, or a structure in which the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer 513 are combined, or the like. For these structures, refer to the description thereof.

[0259] A second electrode 404 is formed to cover the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in the second embodiment. When light is extracted from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. The second electrode 404 is connected to a pad 412 to supply a voltage.

[0260] As described above, the lighting device described in this embodiment includes a light-emitting device having the first electrode 401, the EL layer 403, and the second electrode 404. Since the light-emitting device has high emission efficiency, the lighting device in this embodiment can have low power consumption.

[0261] The lighting device is completed by adhering and sealing the substrate 400 on which the light-emitting device having the above-mentioned configuration is formed and the sealing substrate 407 using the sealing materials 405 and 406. Either one of the sealing materials 405 and 406 may be used. Also, a desiccant may be mixed into the inner sealing material 406 (not shown in FIG. 8B), which allows it to adsorb moisture and improves reliability.

[0262] Moreover, the pad 412 and a part of the first electrode 401 can be extended outside the sealing materials 405 and 406 to serve as an external input terminal. Also, an IC chip 420 equipped with a converter or the like may be provided thereon.

[0263] As described above, the lighting device described in this embodiment uses the light-emitting device described in Embodiment 2 as its EL element, and can be a light-emitting device with low power consumption.

[0264] (Embodiment 5) In this embodiment, an example of an electronic device including the light-emitting device described in Embodiment 2 as a part thereof will be described. The light-emitting device described in Embodiment 2 has good light-emitting efficiency and low power consumption. As a result, the electronic device described in this embodiment can be an electronic device having a light-emitting portion with low power consumption.

[0265] Examples of electronic devices to which the light-emitting devices are applied include television sets (also called televisions or television receivers), computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game machines, personal digital assistants, audio playback devices, large game machines such as pachinko machines, etc. Specific examples of these electronic devices are shown below.

[0266] 9A illustrates an example of a television set. In the television set, a display portion 7103 is incorporated in a housing 7101. Here, the housing 7101 is supported by a stand 7105. Images can be displayed by the display portion 7103, and the display portion 7103 has the light-emitting devices described in Embodiment 2 arranged in a matrix.

[0267] The television device can be operated using an operation switch provided on the housing 7101 or a separate remote control 7110. Using operation keys 7109 provided on the remote control 7110, the channel and volume can be controlled, and an image displayed on the display portion 7103 can be operated. The remote control 7110 may be provided with a display portion 7107 that displays information output from the remote control 7110.

[0268] The television device is configured to include a receiver and a modem, etc. The receiver can receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it is also possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0269] FIG. 9B1 shows a computer, which includes a main body 7201, a housing 7202, a display portion 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. Note that this computer is manufactured by arranging the light-emitting devices described in Embodiment 2 in a matrix and using them for the display portion 7203. The computer of FIG. 9B1 may have a form as shown in FIG. 9B2. The computer of FIG. 9B2 is provided with a second display portion 7210 instead of the keyboard 7204 and the pointing device 7206. The second display portion 7210 is a touch panel type, and input can be performed by operating the display for input displayed on the second display portion 7210 with a finger or a dedicated pen. The second display portion 7210 can display not only the display for input but also other images. The display portion 7203 may also be a touch panel. The two screens are connected by a hinge, which can prevent the screens from being scratched or damaged during storage or transportation.

[0270] 9C shows an example of a mobile terminal. The mobile phone includes a display portion 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone includes the display portion 7402 in which the light-emitting devices described in Embodiment 2 are arranged in a matrix.

[0271] 9C can be configured so that information can be input by touching the display portion 7402 with a finger or the like. In this case, operations such as making a call or composing an e-mail can be performed by touching the display portion 7402 with a finger or the like.

[0272] The screen of the display unit 7402 has three main modes. The first is a display mode that is mainly for displaying images, the second is an input mode that is mainly for inputting information such as characters, and the third is a display + input mode that combines the display mode and the input mode.

[0273] For example, when making a call or composing an e-mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and the character input operation may be performed by inputting characters 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 portion 7402.

[0274] In addition, by providing a detection device having a sensor for detecting tilt, such as a gyro or an acceleration sensor, inside the mobile terminal, the orientation of the mobile terminal (portrait or landscape) can be determined and the screen display of the display portion 7402 can be automatically switched.

[0275] The screen mode can be switched by touching the display portion 7402 or by operating operation buttons 7403 on the housing 7401. The mode can also be switched depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display portion is moving image data, the mode is switched to the display mode, and if it is text data, the mode is switched to the input mode.

[0276] In addition, in the input mode, a signal detected by an optical sensor of the display portion 7402 may be detected, and if there is no input by a touch operation on the display portion 7402 for a certain period of time, the screen mode may be controlled to be switched from the input mode to the display mode.

[0277] The display portion 7402 can also function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger to capture an image of a palm print, a fingerprint, or the like. In addition, finger veins, palm veins, or the like can be captured by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light for the display portion.

[0278] FIG. 10A is a schematic diagram showing an example of a cleaning robot.

[0279] The cleaning robot 5100 has a display 5101 arranged on the top surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and an operation button 5104. Although not shown, the bottom surface of the cleaning robot 5100 is provided with tires, a suction port, and the like. The cleaning robot 5100 also has various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezoelectric sensor, an optical sensor, and a gyro sensor. The cleaning robot 5100 also has wireless communication means.

[0280] The cleaning robot 5100 can move by itself, detect dirt 5120, and suck up the dirt from a suction port provided on the bottom surface.

[0281] In addition, the cleaning robot 5100 can analyze the image captured by the camera 5102 and determine the presence or absence of obstacles such as walls, furniture, steps, etc. Furthermore, when an object that may become entangled in the brush 5103, such as a wire, is detected by image analysis, the rotation of the brush 5103 can be stopped.

[0282] The remaining battery level, the amount of sucked up dirt, etc. can be displayed on the display 5101. The route traveled by the cleaning robot 5100 may be displayed on the display 5101. The display 5101 may be a touch panel, and an operation button 5104 may be provided on the display 5101.

[0283] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when he or she is away from home. Also, the display on the display 5101 can be confirmed on a portable electronic device such as a smartphone.

[0284] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0285] The robot 2100 shown in FIG. 10B includes a computing device 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.

[0286] The microphone 2102 has a function of detecting the user's voice, environmental sounds, etc. The speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104.

[0287] The display 2105 has a function of displaying various information. The robot 2100 can display information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may also be a removable information terminal, and by installing it in a fixed position on the robot 2100, charging and data transfer are possible.

[0288] The upper camera 2103 and the lower camera 2106 have a function of capturing images of the surroundings of the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of an obstacle in the moving direction when the robot 2100 moves forward using the moving mechanism 2108. The robot 2100 can recognize the surrounding environment and move safely using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107. The light-emitting device of one embodiment of the present invention can be used for the display 2105.

[0289] 10C is a diagram showing an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, a connection terminal 5006, a sensor 5007 (including a function for measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared), a microphone 5008, a display unit 5002, a support unit 5012, and an earphone 5013.

[0290] The light-emitting device of one embodiment of the present invention can be used for the display portion 5001 and the display portion 5002 .

[0291] 11 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 FIG. 11 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.

[0292] FIG. 12 shows an example in which the light-emitting device described in Embodiment 2 is used as an indoor lighting device 3001. Since the light-emitting device described in Embodiment 2 has high emission efficiency, it can be used as a lighting device with low power consumption. In addition, since the light-emitting device described in Embodiment 2 can be made large, 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.

[0293] The light-emitting device described in Embodiment 2 can also be mounted on a windshield or dashboard of an automobile. FIG 13 shows an example in which the light-emitting device described in Embodiment 2 is used on a windshield or dashboard of an automobile. Display regions 5200 to 5203 are displays provided using the light-emitting device described in Embodiment 2.

[0294] A display region 5200 and a display region 5201 are display devices equipped with the light-emitting device described in embodiment 2, which is provided on the windshield of an automobile. The light-emitting device described in embodiment 2 can be a so-called see-through display device in which the opposite side can be seen through by manufacturing the first electrode and the second electrode using light-transmitting electrodes. If the display is in a see-through state, the display device can be installed on the windshield of an automobile without interfering with the view. When a transistor for driving is provided, a light-transmitting transistor such as an organic transistor made of an organic semiconductor material or a transistor using an oxide semiconductor is preferably used.

[0295] A display area 5202 is a display device provided on a pillar and equipped with the light-emitting device described in Embodiment 2. By displaying an image from an imaging means provided on the vehicle body in the display area 5202, the view blocked by the pillar can be complemented. Similarly, a display area 5203 provided on the dashboard can complement the view blocked by the vehicle body by displaying an image from an imaging means provided on the outside of the vehicle, thereby compensating for blind spots and improving safety. By displaying an image to complement the invisible parts, safety can be confirmed more naturally and without discomfort.

[0296] The display area 5203 can also provide various other information, such as navigation information, speedometer and tachometer settings, etc. The display items and layout can be changed as appropriate to suit the user's preferences. Note that this information can also be provided in the display areas 5200 to 5202. The display areas 5200 to 5203 can also be used as lighting devices.

[0297] 14A and 14B show a foldable mobile information terminal 5150. The foldable mobile information terminal 5150 includes a housing 5151, a display area 5152, and a bending portion 5153. Fig. 14A shows the mobile information terminal 5150 in an unfolded state. Fig. 14B shows the mobile information terminal in a folded state. Although the mobile information terminal 5150 has a large display area 5152, it is compact and highly portable when folded.

[0298] 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, and when folding, the expandable member stretches. The bending portion 5153 is folded with a curvature radius of 2 mm or more, preferably 3 mm or more.

[0299] Note that the display region 5152 may be a touch panel (input / output device) equipped with a touch sensor (input device). The light-emitting device of one embodiment of the present invention can be used for the display region 5152.

[0300] 15A to 15C show a foldable portable information terminal 9310. Fig. 15A shows the portable information terminal 9310 in an unfolded state. Fig. 15B shows the portable information terminal 9310 in a state in the process of changing from one of the unfolded state and the folded state to the other. Fig. 15C shows the portable information terminal 9310 in a folded state. The portable information terminal 9310 has excellent portability in a folded state, and has excellent viewability of the display due to a seamless wide display area in an unfolded state.

[0301] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). The display panel 9311 can be reversibly transformed from an unfolded state of the mobile information terminal 9310 to a folded state by bending the two housings 9315 via the hinges 9313. The light-emitting device of one embodiment of the present invention can be used for the display panel 9311.

[0302] The organic compound according to one embodiment of the present invention can be used in electronic elements such as organic thin-film solar cells (OPV) and organic photodiodes (OPD). More specifically, since the organic compound has carrier transport properties, it can be used in a carrier transport layer or a carrier injection layer. In addition, by using a mixed film with an acceptor substance, it can be used as a charge generation layer. In addition, since the organic compound is photoexcited, it can be used as a power generation layer or an active layer.

[0303] Note that the structure described in this embodiment mode can be used by appropriately combining the structures described in any of Embodiment Modes 1 to 4.

[0304] As described above, the light-emitting device having the light-emitting device described in Embodiment 2 has a very wide range of application, and can be applied to electronic devices in a variety of fields. By using the light-emitting device described in Embodiment 2, electronic devices with low power consumption can be obtained. EXAMPLES

[0305] <Synthesis Example 1> In this example, a method for synthesizing 4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhA2CzBfpm), which is an organic compound shown as structural formula (100) in Embodiment 1, will be described in detail. The structural formula of 4DPhA2CzBfpm is shown below.

[0306] [ka]

[0307] <Synthesis of 4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhA2CzBfpm)> After replacing the inside of a 50mL three-neck flask with nitrogen, 79mg (2.0mmol) of sodium hydride (NaH) and 15mL of dehydrated N,N-dimethylformamide (DMF) were added and stirred at 0℃. 0.72g (1.4mmol) of 3,6-bis(N,N-diphenylamino)carbazole was added to the mixture and stirred at 0℃ for 30 minutes. Then, 0.27g (1.3mmol) of 4-chlorobenzofuro[3,2-d]pyrimidine was added and stirred at room temperature for 18 hours. After a predetermined time, water was poured into the mixture and the precipitated solid was collected by suction filtration. The obtained solid was purified by silica gel column chromatography (developing solvent toluene:ethyl acetate=4:1) and further recrystallized with a mixed solvent of ethyl acetate and methanol, and 0.62g (0.93mmol) of the target yellow solid was obtained with a yield of 71%. The synthesis scheme of this synthesis example is shown below.

[0308] [ka]

[0309] The yellow solid (0.61 g) was purified by train sublimation under the conditions of a pressure of 3.4 Pa, an argon flow rate of 5 mL / min, and a temperature of 290°C. After the purification, 0.55 g of yellow powder of 4DPhA2CzBfpm was obtained with a recovery rate of 84%.

[0310] Nuclear magnetic resonance spectroscopy of the obtained compound ( 1 The results of measurement by H NMR are shown in Figures 16A and 16B. Note that Figure 16B is a graph showing an enlarged range from 6.5 ppm to 9.5 ppm in Figure 16A. The numerical data are shown below. 1 H NMR (DMSO-d6,300MHz): δ=6.92-7.03(m,12H), 7.20-7.29(m,10H), 7.61-7.68(m, 1H), 7.81-7.93(m,4H), 8.02(d,J=2.2Hz,2H), 8.36(d,J=7.3Hz,1H), 9.29(s,1H).

[0311] Next, the results of measuring the absorption spectrum and emission spectrum of 4DPhA2CzBfpm in a toluene solution are shown in Figure 17. The absorption spectrum was measured using a UV-visible spectrophotometer (V550 model, manufactured by JASCO Corporation), and the spectrum measured by putting only toluene into a quartz cell was subtracted. The emission spectrum was measured using a fluorometer (FP-920, manufactured by JASCO Corporation).

[0312] The absorption and fluorescence spectra of 4DPhA2CzBfpm in a thin film state are shown in Figure 18, and the phosphorescence spectrum in Figure 19. The absorption spectrum was measured using a spectrophotometer (Hitachi High-Technologies Corporation, Spectrophotometer U4100). The solid thin film for the absorption spectrum measurement was prepared on a quartz substrate by vacuum deposition. The fluorescence and phosphorescence spectra were measured using a micro PL device LabRAM HR-PL (Horiba, Ltd.). The measurement temperature was 10K, a He-Cd laser (325nm) was used as the excitation light, and a CCD detector was used as the detector. The sample thin film was formed on a quartz substrate with a thickness of about 50nm, and another quartz substrate was attached to the deposition surface side of the quartz substrate in a nitrogen atmosphere, and then used for the measurement. Note that the measurement of this emission spectrum was performed at a low temperature (10K), so in addition to the fluorescence, which is the main emission component, some phosphorescence was also observed in the normal emission spectrum measurement. The spectrum obtained by measuring the time-resolved emission spectrum (integrated from 20 ms to 120 ms after irradiation with excitation light) focusing on emission with a long emission lifetime was regarded as mainly phosphorescence.

[0313] From FIG. 17, the toluene solution of 4DPhA2CzBfpm showed an absorption peak at 394 nm, and the emission wavelength peak was 539 nm (excitation wavelength 394 nm). Also, from FIG. 18, the thin film of 4DPhA2CzBfpm showed absorption peaks at 401 nm, 363 nm, and 301 nm, and the fluorescence spectrum peak was around 530 nm (excitation wavelength 325 nm). Also, from FIG. 19, the shortest wavelength peak in the phosphorescence spectrum of 4DPhA2CzBfpm was at 527 nm, and it was found that it is a substance with a high T1 level. Note that the peak value read was shorter in phosphorescence than in fluorescence, but the phosphorescence spectrum was shifted to a slightly longer wavelength overall than the fluorescence spectrum. From these results, it was confirmed that 4DPhA2CzBfpm emits green light, and it was found that it can be used as a light-emitting material, or a host material for fluorescent or phosphorescent light-emitting materials.

[0314] The index of the T1 level can be calculated using the phosphorescence spectrum. A tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side, and the energy of the wavelength of the extrapolated line can be regarded as the T1 level. The index of the S1 level can be calculated using the fluorescence spectrum. A tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side, and the energy of the wavelength of the extrapolated line can be regarded as the S1 level.

[0315] The T1 level of 4DPhA2CzBfpm was calculated to be 2.49 eV from FIG. 19, and the S1 level was calculated to be 2.58 eV from FIG. 18. From this result, the difference between the S1 level and the T1 level of 4DPhA2CzBfpm, ΔE ST In general, the ΔE of a material with TADF properties is 0.08 eV. ST It is said that ΔE of 4DPhA2CzBfpm is preferably 0.2 eV or less. ST is a sufficiently small value to have TADF properties. EXAMPLES

[0316] <Synthesis Example 2> In this synthesis example, a method for synthesizing 8-phenyl-4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 8Ph-4DPhA2CzBfpm), which is an organic compound shown as structural formula (101) in embodiment 1, will be described in detail. The structural formula of 8Ph-4DPhA2CzBfpm is shown below.

[0317] [ka]

[0318] <Synthesis of 8-phenyl-4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 8Ph-4DPhA2CzBfpm)> After replacing the atmosphere in a 100mL three-neck flask with nitrogen, 130mg (3.4mmol) of sodium hydride (NaH) and 30mL of dehydrated N,N-dimethylformamide (DMF) were added and stirred at 0℃. 1.2g (2.5mmol) of 3,6-bis(N,N-diphenylamino)carbazole was added and stirred at 0℃ for 30 minutes. Then, 0.63g (2.2mmol) of 4-chloro-8-phenylbenzofuro[3,2-d]pyrimidine was added and stirred at room temperature for 110 hours. After a certain time, water was poured into the reaction mixture and the precipitated solid was collected by suction filtration. The obtained solid was purified by silica gel column chromatography (developing solvent toluene:ethyl acetate=4:1) and further recrystallized with a mixed solvent of toluene and methanol, obtaining 1.5g of the target yellow solid with a yield of 91%. The synthesis scheme of this synthesis is shown below.

[0319] [ka]

[0320] The resulting yellow solid (1.5 g) was purified by train sublimation under the conditions of a pressure of 3.1 Pa, an argon flow rate of 5 mL / min, and a temperature of 335°C. After the purification, 1.4 g of yellow powder of 8Ph-4DPhA2CzBfpm was obtained with a recovery rate of 93%.

[0321] Nuclear magnetic resonance spectroscopy of the obtained compound ( 1 The results of measurement by H NMR are shown in Figures 20A and 20B. Note that Figure 20B is a graph showing an enlarged range from 6.5 ppm to 9.5 ppm in Figure 20A. The numerical data is shown below. 1 H NMR (CD 2 Cl 2 ,300MHz):δ=6.93-7.01(m,4H), 7.05-7.12(m,8H), 7.19-7.29(m,10H), 7.39-7.46(m,1H), 7.49-7 .56(m,2H), 7.72-7.82(m,7H), 8.00(dd,J=1.8Hz,8.8Hz,1H), 8.53(d,J=2.2Hz,1H), 9.23(s,1H).

[0322] Next, the results of measuring the absorption spectrum and emission spectrum of 8Ph-4DPhA2CzBfpm in a toluene solution are shown in Figure 21. The absorption spectrum was measured using a UV-visible spectrophotometer (V550 model, manufactured by JASCO Corporation), and the spectrum measured by putting only toluene into a quartz cell was subtracted. A fluorometer (FP-8600, manufactured by JASCO Corporation) was used to measure the emission spectrum.

[0323] The absorption and fluorescence spectra of 8Ph-4DPhA2CzBfpm in a thin film state are shown in Figure 22, and the phosphorescence spectrum is shown in Figure 23. A spectrophotometer (Hitachi High-Technologies Corporation, Spectrophotometer U4100) was used to measure the absorption spectrum. The solid thin film for measuring the absorption spectrum was prepared on a quartz substrate by vacuum deposition. A micro PL device LabRAM HR-PL (Horiba, Ltd.) was used to measure the fluorescence and phosphorescence spectra of the thin film. The measurement temperature was 10K, a He-Cd laser (325nm) was used as the excitation light, and a CCD detector was used as the detector. The sample thin film was formed on a quartz substrate with a thickness of about 50nm, and another quartz substrate was attached to the deposition surface side of the quartz substrate in a nitrogen atmosphere, and then used for the measurement. Note that the measurement of this emission spectrum was performed at a low temperature (10K), so in a normal emission spectrum measurement, in addition to the main emission component, fluorescence, some phosphorescence was also observed. The spectrum obtained by measuring the time-resolved emission spectrum (integrated from 20 ms to 120 ms after irradiation with excitation light) focusing on emission with a long emission lifetime was regarded as mainly phosphorescence.

[0324] As shown in FIG. 21, the toluene solution of 8Ph-4DPhA2CzBfpm had absorption peaks at 397 nm and 360 nm, and the emission wavelength peak was 545 nm (excitation wavelength 397 nm). As shown in FIG. 22, the thin film of 8Ph-4DPhA2CzBfpm had absorption peaks at 410 nm, 363 nm, and 301 nm, and the fluorescence spectrum peak was at 530 nm (excitation wavelength 325 nm). As shown in FIG. 23, the shortest wavelength peak in the phosphorescence spectrum of 8Ph-4DPhA2CzBfpm was at 531 nm, indicating that the substance has a high T1 level. The peak values ​​read were shorter in phosphorescence than in fluorescence, but the phosphorescence spectrum was shifted to a slightly longer wavelength overall than the fluorescence spectrum. These results confirmed that 8Ph-4DPhA2CzBfpm emits green light and can be used as a light-emitting material or a host material for fluorescent or phosphorescent light-emitting materials.

[0325] The index of the T1 level can be calculated using the phosphorescence spectrum. A tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side, and the energy of the wavelength of the extrapolated line can be regarded as the T1 level. The index of the S1 level can be calculated using the fluorescence spectrum. A tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side, and the energy of the wavelength of the extrapolated line can be regarded as the S1 level.

[0326] The T1 level of 8Ph-4DPhA2CzBfpm was calculated to be 2.48 eV from FIG. 23, and the S1 level was calculated to be 2.56 eV from FIG. 22. From this result, the difference between the T1 level and the S1 level of 8PhA2CzBfpm, ΔE ST The ΔE of materials with TADF properties is generally 0.08 eV. ST It is said that ΔE of 8Ph-4DPhA2CzBfpm is preferably 0.2 eV or less. ST is a sufficiently small value to have TADF properties. EXAMPLES

[0327] <Synthesis Example 3> In this synthesis example, a method for synthesizing 4-[3-(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhACzBfpm) shown as structural formula (102) in embodiment 1 will be described in detail. The structural formula of 4DPhACzBfpm is shown below.

[0328] [ka]

[0329] <Synthesis of 4-[3-(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhACzBfpm)> After replacing the inside of a 50mL three-neck flask with nitrogen, 82mg (2.0mmol) of sodium hydride (NaH) and 15mL of dehydrated N,N-dimethylformamide (DMF) were added and stirred at 0℃. 0.50g (1.5mmol) of 3-(N,N-diphenylamino)carbazole was added to this and stirred at 0℃ for 30 minutes. Then, 0.28g (1.4mmol) of 4-chlorobenzofuro[3,2-d]pyrimidine was added and stirred at room temperature for 18 hours. After a predetermined time, water was poured into this mixture and the precipitated solid was collected by suction filtration. The obtained solid was purified by silica gel column chromatography (developing solvent toluene:ethyl acetate=4:1) to obtain 0.76g of the target yellow solid. Ultrasonication was applied to a suspension of the obtained solid in methanol, and the solid was collected by suction filtration to obtain 0.50g (0.99mmol) of the target yellow solid with a yield of 73%. The synthesis scheme of this synthesis is shown below.

[0330] [ka]

[0331] The yellow solid (0.49 g) was purified by train sublimation under the conditions of 3.4 Pa pressure, 5 mL / min argon flow rate, and 235°C. After sublimation purification, 0.36 g of yellow powder of 4DPhACzBfpm was obtained with a recovery rate of 74%.

[0332] Nuclear magnetic resonance spectroscopy of the obtained compound ( 1 The results of the measurements by H-NMR are shown in Figures 24A and 24B. Note that Figure 24B is a graph showing an enlarged range from 6.5 ppm to 9.5 ppm in Figure 24A. The numerical data are shown below. 1 H NMR (DMSO-d6,300MHz): δ=6.97-7.08(m,6H), 7.21-7.40(m,6H), 7.46-7.54(m,1H), 7.61-7.68(m,1H) , 7.80-7.93(m,4H), 8.07(d,J=1.8Hz,1H), 8.24(d,J=7.3Hz,1H), 8.37(d,J=7.3Hz,1H), 9.31(s,1H).

[0333] Next, the results of measuring the absorption spectrum and emission spectrum of 4DPhACzBfpm in a toluene solution are shown in Figure 25. The absorption spectrum was measured using a UV-visible spectrophotometer (V550 model, manufactured by JASCO Corporation), and the spectrum measured by putting only toluene into a quartz cell was subtracted from the absorption spectrum. A fluorometer (FP-920, manufactured by JASCO Corporation) was used to measure the emission spectrum.

[0334] The absorption and fluorescence spectra of 4DPhACzBfpm in a thin film state are shown in Figure 26, and the phosphorescence spectrum in Figure 27. The absorption spectrum was measured using a spectrophotometer (Hitachi High-Technologies Corporation, Spectrophotometer U4100). The solid thin film for measuring the absorption spectrum was prepared on a quartz substrate by vacuum deposition. The fluorescence and phosphorescence spectra were measured using a micro PL device LabRAM HR-PL (Horiba, Ltd.). The measurement temperature was 10K, a He-Cd laser (325nm) was used as the excitation light, and a CCD detector was used as the detector. The sample thin film was formed on a quartz substrate with a thickness of about 50nm, and another quartz substrate was attached to the deposition surface side of the quartz substrate in a nitrogen atmosphere, and then used for the measurement. Note that the measurement of this emission spectrum was performed at a low temperature (10K), and in addition to the fluorescence, which is the main emission component, some phosphorescence was also observed in a normal emission spectrum measurement. The spectrum obtained by measuring the time-resolved emission spectrum (integrated from 20 ms to 120 ms after irradiation with excitation light) focusing on emission with a long emission lifetime was regarded as mainly phosphorescence.

[0335] As shown in FIG. 25, the toluene solution of 4DPhACzBfpm had an absorption peak at 375 nm, and the emission wavelength peak was 532 nm (excitation wavelength 375 nm). As shown in FIG. 26, the thin film of 4DPhACzBfpm had absorption peaks at 379 nm and 293 nm, and the fluorescence spectrum peak was around 525 nm (excitation wavelength 325 nm). As shown in FIG. 27, the shortest wavelength peak in the phosphorescence spectrum of 4DPhACzBfpm was at 521 nm, and it was found to be a substance with a high T1 level. The peak values ​​read were shorter in phosphorescence than in fluorescence, but the phosphorescence spectrum was generally slightly shifted to longer wavelengths than the fluorescence spectrum. From these results, it was confirmed that 4DPhACzBfpm emits green light, and it was found to be usable as a light-emitting material, or a host material for fluorescent or phosphorescent light-emitting materials.

[0336] The index of the T1 level can be calculated using the phosphorescence spectrum. A tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side, and the energy of the wavelength of the extrapolated line can be regarded as the T1 level. The index of the S1 level can be calculated using the fluorescence spectrum. A tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side, and the energy of the wavelength of the extrapolated line can be regarded as the S1 level.

[0337] The T1 level of 4DPhACzBfpm was calculated to be 2.56 eV from FIG. 27, and the S1 level was calculated to be 2.64 eV from FIG. 26. From this result, the difference between the T1 level and the S1 level of 4DPhACzBfpm, ΔE ST The ΔE of materials with TADF properties is generally 0.08 eV. ST It is said that ΔE of 4DPhACzBfpm is preferably 0.2 eV or less. ST is a sufficiently small value to have TADF properties. EXAMPLES

[0338] In this example, the distribution of the lowest unoccupied molecular orbital (LUMO) level and the distribution of the highest occupied molecular orbital (HOMO) level of organic compounds represented by the following structural formulas (100) to (104), which are organic compounds according to one embodiment of the present invention, were examined by molecular orbital calculation.

[0339] [ka]

[0340] The calculation was performed by density functional theory (DFT) for the most stable structure in the singlet ground state. At this time, vibration analysis was performed for each most stable structure. 6-311G was applied to all atoms as the basis function. Furthermore, to improve the accuracy of the calculation, p-functions were added to hydrogen atoms and d-functions were added to non-hydrogen atoms as polarized basis sets. The functional used was B3LYP. In addition, the HOMO level and LUMO level of the calculated most stable singlet structure were calculated. In DFT, the total energy of a molecule is expressed as the sum of the potential energy, electrostatic energy between electrons, kinetic energy of electrons, and exchange-correlation energy, which includes all complex interactions between electrons. In addition, in DFT, the exchange-correlation interaction is approximated by a functional (meaning a function of a function) of a single-electron potential expressed in electron density, so the electronic state can be obtained with higher accuracy.

[0341] The quantum chemical calculation program used was Gaussian 09. The calculations were performed using a high-performance computer (SGI, Altix4700).

[0342] The results are shown in Fig. 28 and Fig. 29. As shown in Fig. 28 and Fig. 29, it was found that the above five substances, which are organic compounds according to one embodiment of the present invention, have a LUMO level mainly in the benzofuropyrimidine skeleton and a HOMO level mainly in the carbazole skeleton and the diphenylamine skeleton, which are spatially separated from each other.

[0343] In addition, the organic compounds represented by the structural formula (103) and the structural formula (104) in which the carbazole skeleton is bonded to the benzofuropyrimidine skeleton via a phenylene group have a smaller ΔE ST The ΔE of the structural formula (104) in which the phenylene group is substituted at the meta position is smaller than that of the structural formula (103) in which the phenylene group is substituted at the para position. ST These ΔE ST The lowest excitation energy of the singlet state (S1) and the lowest excitation energy of the triplet state (T1) were calculated by the time-dependent density functional theory (TD-DFT) using the most stable structure of the singlet ground state, and the lowest excitation energy of the triplet state (T1) was calculated from the difference. The basis set was 6-311G(d,p) and the functional was B3LYP.

[0344] To induce TADF, it is necessary to preferentially induce reverse intersystem crossing from T1 to S1 and to make it faster than the non-radiative decay rate from T1 to S0. This requires an energy difference ΔE between the S1 and T1 states. ST It is effective to reduce ΔE ST In order to reduce this, it is necessary to reduce the overlap density between the HOMO and LUMO, and it is said that molecular design that spatially separates the HOMO and LUMO is effective.

[0345] The above-mentioned five substances, which are organic compounds according to one embodiment of the present invention, are organic compounds having exactly such molecular structures. In particular, the organic compounds represented by the structural formulas (100) to (102) synthesized in Examples 1 to 3 have actually measured ΔE ST The photoelectron scattering was also small at 0.08 eV, indicating that this is an organic compound with high TADF properties. EXAMPLES

[0346] In this example, a light-emitting device 1 using an organic compound according to one embodiment of the present invention will be described. The structural formula of the organic compound used in the light-emitting device 1 is shown below.

[0347] [ka]

[0348] (Method of fabricating light-emitting device 1) First, indium tin oxide containing silicon oxide (ITSO) was formed by sputtering on a glass substrate to form a first electrode 101. The thickness of the first electrode 101 was 70 nm, and the electrode area was 2 mm×2 mm.

[0349] 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.

[0350] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and then the substrate was allowed to cool for about 30 minutes.

[0351] Next, the substrate on which the first electrode 101 was formed was fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (i) and molybdenum oxide (VI) were co-deposited on the first electrode 101 by a deposition method using resistance heating to a thickness of 40 nm in a weight ratio of 1:0.5 (=DBT3P-II:molybdenum oxide) to form a hole injection layer 111.

[0352] Next, 9-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]9H-carbazole (abbreviation: mCzFLP) represented by the above structural formula (ii) was evaporated onto the hole injection layer 111 to a thickness of 20 nm to form a hole transport layer 112.

[0353] Next, 9,9'-(pyrimidine-4,6-diyldi-3,1-phenylene)bis(9H-carbazole) (abbreviation: 4,6mCzP2Pm) represented by the above structural formula (iii) and 4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhA2CzBfpm) represented by the above structural formula (100) were co-deposited to a thickness of 30 nm in a weight ratio of 1:0.1 (=4,6mCzP2Pm:4DPhA2CzBfpm) to form the light-emitting layer 113.

[0354] Then, 4,6mCzP2Pm was formed on the light-emitting layer 113 to a thickness of 20 nm, and 2,9-di(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (iv) was further evaporated to a thickness of 15 nm to form the electron transport layer 114.

[0355] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was evaporated to a thickness of 200 nm to form the second electrode 102, thereby producing the light-emitting device 1 of this embodiment.

[0356] The element structure of the above light emitting device is summarized in the table below.

[0357] [Table 1]

[0358] The above light-emitting device was sealed with a glass substrate in a glove box with a nitrogen atmosphere to prevent the light-emitting device from being exposed to the atmosphere (a sealant was applied around the element, and UV treatment was performed during sealing, followed by heat treatment at 80°C for 1 hour), and then the initial characteristics were measured.

[0359] The luminance-current density characteristics of the light-emitting device 1 are shown in Fig. 30, the current efficiency-luminance characteristics in Fig. 31, the luminance-voltage characteristics in Fig. 32, the current-voltage characteristics in Fig. 33, the external quantum efficiency-luminance characteristics in Fig. 34, and the emission spectrum in Fig. 35. 2 The main characteristics of the vicinity are as follows:

[0360] [Table 2]

[0361] 30 to 34, it can be seen that the light-emitting device 1 of one embodiment of the present invention is a light-emitting element having excellent characteristics and a very high external quantum efficiency of 25% or more. This value is far beyond the theoretical limit of fluorescence emission in current excitation, and suggests that energy from triplet excitons contributes to light emission.

[0362] In the light-emitting device 1, as shown in Example 4, the HOMO and LUMO of the light-emitting material 4DPhA2CzBfpm exist in a state in which they are spatially separated within the molecule, and as measured in Example 1, ΔE ST This indicates that 4DPhA2CzBfpm is a substance that is likely to express TADF.

[0363] The transient EL characteristics of the light-emitting device 1 were measured, and the results are shown in Figures 36A and 36B. A picosecond fluorescence lifetime measurement system (Hamamatsu Photonics) was used for the measurements. In this measurement, a rectangular pulse voltage was applied to the light-emitting device, and the light emission that decayed from the falling edge of the voltage was measured with a streak camera in a time-resolved manner. The measurements were also performed at room temperature (25°C).

[0364] In Figures 36A and 36B, the vertical axis indicates the intensity normalized by the emission intensity in a state where carriers are steadily injected (when the pulse voltage is on). The horizontal axis indicates the elapsed time from the fall of the pulse voltage. Note that the measurement time ranges are different between Figures 36A and 36B.

[0365] From the transient EL characteristics shown in Figures 36A and 36B, at least one luminescence component with a fast decay of about 0.4 μs (transient lifetime) and another luminescence component with a slow decay of about 9 μs were observed from light-emitting device 1. Of these, the luminescence component with a fluorescence lifetime of 9 μs is delayed fluorescence based on reverse intersystem crossing, and it was found that light-emitting device 1 exhibits TADF. This also shows that light-emitting device 1 exhibits TADF by using 4DPhA2CzBfpm as the light-emitting material, and triplet excitons are involved in the light emission, resulting in a light-emitting device that emits light with very good luminous efficiency. EXAMPLES

[0366] In this example, a light-emitting device 2 using an organic compound according to one embodiment of the present invention will be described. The structural formula of the organic compound used in the light-emitting device 2 is shown below.

[0367] [ka]

[0368] (Method of manufacturing light-emitting device 2) First, indium tin oxide containing silicon oxide (ITSO) was formed by sputtering on a glass substrate to form a first electrode 101. The thickness of the first electrode 101 was 70 nm, and the electrode area was 2 mm×2 mm.

[0369] 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.

[0370] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and the substrate was then allowed to cool for about 30 minutes.

[0371] Next, the substrate on which the first electrode 101 was formed was fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (i) and molybdenum oxide (VI) were co-deposited on the first electrode 101 by a deposition method using resistance heating to a thickness of 40 nm in a weight ratio of 1:0.5 (=DBT3P-II:molybdenum oxide) to form a hole injection layer 111.

[0372] Next, 9-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]9H-carbazole (abbreviation: mCzFLP) represented by the above structural formula (ii) was evaporated onto the hole injection layer 111 to a thickness of 20 nm to form the hole transport layer 112.

[0373] Next, 2-(9,9'-spirobi[fluoren]-3-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: SF3-TZN) represented by the above structural formula (v) and 8-phenyl-4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 8Ph-4DPhA2CzBfpm) represented by the above structural formula (101) were co-deposited to a thickness of 30 nm in a weight ratio of 1:0.1 (=SF3-TZN:8Ph-4DPhA2CzBfpm) to form the light-emitting layer 113.

[0374] Then, 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) represented by the above structural formula (iii) was formed on the light-emitting layer 113 to a thickness of 20 nm, and 2,9-di(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (iv) was further evaporated to a thickness of 15 nm to form the electron transport layer 114.

[0375] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was evaporated to a thickness of 200 nm to form the second electrode 102, thereby producing the light-emitting device 2 of this embodiment.

[0376] The element structure of the above light emitting device is summarized in the table below.

[0377] [Table 3]

[0378] The above light-emitting device was sealed with a glass substrate in a glove box with a nitrogen atmosphere to prevent the light-emitting device from being exposed to the atmosphere (a sealant was applied around the element, and UV treatment was performed during sealing, followed by heat treatment at 80°C for 1 hour), and then the initial characteristics were measured.

[0379] The luminance-current density characteristics of the light-emitting device 2 are shown in FIG. 37, the current efficiency-luminance characteristics in FIG. 38, the luminance-voltage characteristics in FIG. 39, the current-voltage characteristics in FIG. 40, the external quantum efficiency-luminance characteristics in FIG. 41, and the emission spectrum in FIG. 42. 2 The main characteristics of the vicinity are as follows:

[0380] [Table 4]

[0381] 37 to 41 show that the light-emitting device 2 of one embodiment of the present invention is a light-emitting element having excellent characteristics and a very high external quantum efficiency of 25% or more. This value is far beyond the theoretical limit of fluorescence emission in current excitation, and suggests that energy from triplet excitons contributes to light emission.

[0382] In the light-emitting device 2, as shown in Example 4, the HOMO and LUMO of the 8Ph-4DPhA2CzBfpm used as the light-emitting material are present in a state in which they are spatially separated within the molecule, and as measured in Example 2, ΔE ST It is an organic compound with a small valence and prone to reverse intersystem crossing. From these findings, it is believed that 8Ph-4DPhA2CzBfpm is a material that is prone to exhibiting TADF, and that light-emitting device 2 exhibits TADF by using 8PhA2CzBfpm as the light-emitting material, and that the triplet excitons are involved in the light emission, resulting in a light-emitting device that emits light with extremely good luminous efficiency. EXAMPLES

[0383] In this example, a light-emitting device 3 using an organic compound according to one embodiment of the present invention will be described. The structural formula of the organic compound used in the light-emitting device 3 is shown below.

[0384] [ka]

[0385] (Method of manufacturing light-emitting device 3) First, indium tin oxide containing silicon oxide (ITSO) was formed by sputtering on a glass substrate to form a first electrode 101. The thickness of the first electrode 101 was 70 nm, and the electrode area was 2 mm×2 mm.

[0386] 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.

[0387] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and the substrate was then allowed to cool for about 30 minutes.

[0388] Next, the substrate on which the first electrode 101 was formed was fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (i) and molybdenum oxide (VI) were co-deposited on the first electrode 101 by a deposition method using resistance heating to a thickness of 40 nm in a weight ratio of 1:0.5 (=DBT3P-II:molybdenum oxide) to form a hole injection layer 111.

[0389] Next, 9-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]9H-carbazole (abbreviation: mCzFLP) represented by the above structural formula (ii) was evaporated onto the hole injection layer 111 to a thickness of 20 nm to form a hole transport layer 112.

[0390] Next, 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) represented by the above structural formula (iii) and 4-[3-(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhACzBfpm) represented by the above structural formula (102) were co-deposited to a thickness of 30 nm in a weight ratio of 1:0.1 (=4,6mCzP2Pm:4DPhACzBfpm) to form the light-emitting layer 113.

[0391] Then, 4,6mCzP2Pm was formed on the light-emitting layer 113 to a thickness of 20 nm, and 2,9-di(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (iv) was further evaporated to a thickness of 15 nm to form the electron transport layer 114.

[0392] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was evaporated to a thickness of 200 nm to form the second electrode 102, thereby producing the light-emitting device 3 of this embodiment.

[0393] The element structure of the above light emitting device is summarized in the table below.

[0394] [Table 5]

[0395] The above light-emitting device was sealed with a glass substrate in a glove box with a nitrogen atmosphere to prevent the light-emitting device from being exposed to the atmosphere (a sealant was applied around the element, and UV treatment was performed during sealing, followed by heat treatment at 80°C for 1 hour), and then the initial characteristics were measured.

[0396] The luminance-current density characteristics of the light-emitting device 3 are shown in FIG. 43, the current efficiency-luminance characteristics in FIG. 44, the luminance-voltage characteristics in FIG. 45, the current-voltage characteristics in FIG. 46, the external quantum efficiency-luminance characteristics in FIG. 47, and the emission spectrum in FIG. 48. The 1000 cd / m 2 The main characteristics of the vicinity are as follows:

[0397] [Table 6]

[0398] 43 to 47 show that the light-emitting device 3 of one embodiment of the present invention is a light-emitting element having excellent characteristics and a very high external quantum efficiency of 20% or more. This value is far beyond the theoretical limit of fluorescence emission in current excitation, and suggests that energy from triplet excitons contributes to light emission.

[0399] In the light-emitting device 3, as shown in Example 4, the HOMO and LUMO of the light-emitting material 4DPhACzBfpm exist in a state in which they are spatially separated within the molecule, and as measured in Example 3, ΔE ST This indicates that 4DPhACzBfpm is a substance that is likely to express TADF.

[0400] Therefore, the results of measuring the transient EL characteristics of the light-emitting device 3 are shown in Figures 49A and 49B. A picosecond fluorescence lifetime measurement system (manufactured by Hamamatsu Photonics) was used for the measurement. In this measurement, a rectangular pulse voltage was applied to the light-emitting device, and the light emission that decayed from the falling edge of the voltage was measured with a streak camera in a time-resolved manner. The measurement was also performed at room temperature (25°C).

[0401] In Figures 49A and 49B, the vertical axis indicates the intensity normalized by the emission intensity in a state where carriers are steadily injected (when the pulse voltage is on). The horizontal axis indicates the elapsed time from the fall of the pulse voltage. Note that the measurement time ranges are different between Figures 49A and 49B.

[0402] From the transient EL characteristics shown in Figures 49A and 49B, at least one luminescence component with a fast decay of about 0.3 μs (transient lifetime) and one with a slow decay of about 10 μs were observed from the light-emitting device 3. Of these, the luminescence component with a fluorescence lifetime of 10 μs is delayed fluorescence based on reverse intersystem crossing, and it was found that the light-emitting device 3 exhibits TADF. This also shows that the use of 4DPhACzBfpm as the light-emitting material in the light-emitting device 3 results in the expression of TADF, and triplet excitons are involved in the light emission, resulting in a light-emitting device that emits light with very good luminous efficiency. EXAMPLES

[0403] In this example, a light-emitting device 4 using an organic compound according to one embodiment of the present invention will be described. The structural formula of the organic compound used in the light-emitting device 4 is shown below.

[0404] [ka]

[0405] (Method of manufacturing light-emitting device 4) First, indium tin oxide containing silicon oxide (ITSO) was formed by sputtering on a glass substrate to form a first electrode 101. The thickness of the first electrode 101 was 70 nm, and the electrode area was 2 mm×2 mm.

[0406] 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.

[0407] Then, 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and then the substrate was allowed to cool for about 30 minutes.

[0408] Next, the substrate on which the first electrode 101 was formed was fixed to a substrate holder provided in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (i) and molybdenum oxide (VI) were co-deposited on the first electrode 101 by a deposition method using resistance heating to a thickness of 40 nm in a weight ratio of 1:0.5 (=DBT3P-II:molybdenum oxide) to form a hole injection layer 111.

[0409] Next, 9-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]9H-carbazole (abbreviation: mCzFLP) represented by the above structural formula (ii) was evaporated onto the hole injection layer 111 to a thickness of 20 nm to form a hole transport layer 112.

[0410] Next, 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm) represented by the above structural formula (iii), 4-[3,6-bis(N,N-diphenylamino)carbazol-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4DPhA2CzBfpm) represented by the above structural formula (100), and 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (abbreviation: TBRb) were co-deposited to a thickness of 40 nm in a weight ratio of 1:1:0.01 (=4,6mCzP2Pm:4DPhA2CzBfpm:TBRb) to form an emitting layer 113.

[0411] Then, 4,6mCzP2Pm was formed on the light-emitting layer 113 to a thickness of 20 nm, and 2,9-di(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (iv) was further evaporated to a thickness of 15 nm to form the electron transport layer 114.

[0412] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was evaporated to a thickness of 200 nm to form the second electrode 102, thereby producing the light-emitting device 4 of this embodiment.

[0413] The element structure of the above light emitting device is summarized in the table below.

[0414] [Table 7]

[0415] The above light-emitting device was sealed with a glass substrate in a glove box with a nitrogen atmosphere to prevent the light-emitting device from being exposed to the atmosphere (a sealant was applied around the element, and UV treatment was performed during sealing, followed by heat treatment at 80°C for 1 hour), and then the initial characteristics were measured.

[0416] The luminance-current density characteristics of the light-emitting device 4 are shown in FIG. 50, the current efficiency-luminance characteristics in FIG. 51, the luminance-voltage characteristics in FIG. 52, the current-voltage characteristics in FIG. 53, the external quantum efficiency-luminance characteristics in FIG. 54, and the emission spectrum in FIG. 55. The 1000 cd / m 2 The main characteristics of the vicinity are as follows:

[0417] [Table 8]

[0418] 55 and the chromaticity indicate that TBRb is emitting light from the light-emitting device 4. Furthermore, as shown in Figures 50 to 54, the light-emitting device 4 of one embodiment of the present invention is a light-emitting element having excellent characteristics and an external quantum efficiency of 20% or more. This value is far beyond the theoretical limit of fluorescence emission in current excitation, and suggests that energy from triplet excitons contributes to light emission.

[0419] In the light-emitting device 4, 4DPhA2CzBfpm used as one of the host materials has a HOMO and a LUMO that are spatially separated within the molecule as shown in Example 4, and as measured in Example 1, ΔE ST This indicates that 4DPhACzBfpm is a substance that is prone to reverse intersystem crossing.

[0420] Thus, the transient EL characteristics of the light-emitting device 4 were measured, and the results are shown in Figure 56. A picosecond fluorescence lifetime measurement system (manufactured by Hamamatsu Photonics) was used for the measurement. In this measurement, a rectangular pulse voltage was applied to the light-emitting device, and the light emission that decayed from the falling edge of the voltage was measured with a streak camera in a time-resolved manner. The measurement was also performed at room temperature (25°C).

[0421] In Figures 56A and 56B, the vertical axis indicates the intensity normalized by the emission intensity in a state where carriers are steadily injected (when the pulse voltage is on). The horizontal axis indicates the elapsed time from the fall of the pulse voltage. Note that Figures 56A and 56B have different measurement time ranges.

[0422] 56A and 56B, at least a fast-decaying luminescence component with a fluorescence lifetime (transient lifetime) of about 0.2 μs and a slow-decaying luminescence component with a fluorescence lifetime of about 8 μs were observed from the light-emitting device 4. Of these, the luminescence component with a fluorescence lifetime of 8 μs is delayed fluorescence.

[0423] TBRb is a fluorescent substance that does not have TADF properties. From this, it was found that in light-emitting device 4, the triplet excited state of 4DPhA2CzBfpm undergoes reverse intersystem crossing to a singlet excited state, generating a singlet excited state, and energy is transferred from this singlet excited state to TBRb, causing TBRb to emit light. This is a so-called exciton-harvesting fluorescent element, and high efficiency has been achieved. [Explanation of symbols]

[0424] 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: sealing substrate, 412: pad, 420: IC chip, 501: anode, 502: cathode, 511: first light emitting unit, 512: second light emitting unit, 513: charge generation raw layer, 601: driving circuit section (source line driving circuit), 602: pixel section, 603: driving circuit section (gate line driving circuit), 604: sealing 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, 730: insulating film, 770: planarizing insulating film, 772: conductive film, 782: light emitting device, 783: droplet discharge device, 784: droplet, 7 85: layer, 786: EL layer, 788: conductive film, 951: substrate, 952: electrode, 953: insulating layer, 954: partition layer, 955: EL layer, 956: electrode, 1001: substrate, 1002: base insulating film, 1003: gate insulating film, 1006: gate electrode, 1007: gate electrode, 1008: gate electrode, 1020: first interlayer insulating film, 1021: second 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: sealing stopping substrate, 1032: sealing material, 1033: transparent base material, 1034R: red colored layer, 1034G: green colored layer, 1034B: blue colored layer, 1035: black matrix, 1036: overcoat layer, 1037: third interlayer insulating film, 1040: pixel section, 1041: driving circuit section, 1042: peripheral section, 1400: droplet discharge device, 1402: substrate, 1403: droplet discharge means, 1404: imaging means, 1405: head, 1406: dotted line, 1407: control means, 1408: storage medium, 1409: image processing means, 1410: computer, 1411: marker,1412: head, 1413: material supply source, 1414: material supply source, 1415: material supply source, 1416: head, 2001: housing, 2002: light source, 2100: robot, 2110: computing device, 2101: illuminance sensor, 2102: microphone, 2103: upper camera, 2104: speaker, 2105: display, 2106: lower camera, 2107: obstacle sensor 2108: moving mechanism, 3001: lighting device, 5000: housing, 5001: display unit, 5002: display unit, 5003: speaker, 5004: LED lamp, 5006: connection terminal, 5007: sensor, 5008: microphone, 5012: support unit, 5013: earphone, 5100: cleaning robot, 5101: display, 5102: camera, 5103: brush, 510 4: operation button, 5150: mobile information terminal, 5151: housing, 5152: display area, 5153: bending portion, 5120: dust, 5200: display area, 5201: display area, 5202: display area, 5203: display area, 7101: housing, 7103: display unit, 7105: stand, 7107: display unit, 7109: operation key, 7110: remote control unit, 7201: main body, 7202 : Housing, 7203: Display unit, 7204: Keyboard, 7205: External connection port, 7206: Pointing device, 7210: Second display unit, 7401: Housing, 7402: Display unit, 7403: Operation button, 7404: External connection port, 7405: Speaker, 7406: Microphone, 9310: Portable information terminal, 9311: Display panel, 9313: Hinge, 9315: Housing,

Claims

1. An organic compound represented by the following general formula (G2): 【Chemistry 1】 (However, in the above general formula (G2), R １ ~R ８ Each of R is independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted diarylamino group. １ ~R ８ At least one of R is a substituted or unsubstituted diarylamino group. α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. １１ ~R １５ are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring. Q represents an oxygen atom or a sulfur atom.

2. In claim 1, The organic compound, wherein the substituted or unsubstituted diarylamino group is a group represented by the following general formula (g2): 【Chemistry 2】 (However, in the above general formula (g2), Ar １ and Ar ２ each independently represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring.

3. In claim 2, R ３ and R ６ an organic compound in which one or both of the above is a group represented by general formula (g2).

4. An organic compound represented by the following general formula (G3): 【Chemistry 3】 (In the above general formula (G3), Ar ３ ~Ar ６ are each independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. １ , R ２ , R ４ , R ５ , R ７ and R ８ are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a cycloalkyl group having 3 to 7 carbon atoms. In addition, α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. In addition, R １１ ~R １５ are each independently any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring. Q represents an oxygen atom or a sulfur atom.

5. An organic compound represented by the following general formula (G4): 【Chemistry 4】 (In the above general formula (G4), Ar ３ ~Ar ６ Each of R is independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. α represents a substituted or unsubstituted phenylene group, and n is an integer of 0 to 4. １３ is any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring. Q represents an oxygen atom or a sulfur atom.

6. An organic compound represented by the following general formula (G5): 【Chemistry 5】 (In the above general formula (G5), Ar ３ ~Ar ６ are each independently a substituted or unsubstituted aryl group having 6 to 13 carbon atoms forming a ring. １３ is any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 7 carbon atoms, and a substituted or unsubstituted aryl group having 6 to 13 carbon atoms in a ring. Q represents an oxygen atom or a sulfur atom.

7. In any one of claims 1 to 6, An organic compound in which the aryl group having 6 to 13 carbon atoms forming a ring is any one of a phenyl group, a biphenyl group, a naphthyl group, and a fluorenyl group.

8. In any one of claims 1 to 6, An organic compound in which the aryl group having 6 to 13 carbon atoms forming a ring is a phenyl group.

9. In any one of claims 1 to 8, The organic compound wherein Q is an oxygen atom.

10. In any one of claims 1 to 9, An organic compound having a difference between the lowest singlet excitation level and the lowest triplet excitation level of 0.2 eV or less.

11. In any one of claims 1 to 9, An organic compound having a difference between the lowest singlet excitation level and the lowest triplet excitation level of 0.1 eV or less.

12. An organic compound represented by any one of the following structural formulas (100), (101) and (102). 【Chemistry 6】 【Chemistry 7】 【Chemistry 8】

13. A first electrode; A second electrode; and an organic layer sandwiched between the first electrode and the second electrode; An electronic device, wherein the organic layer comprises an organic compound according to claim 1 .

14. A first electrode; A second electrode; and an organic layer sandwiched between the first electrode and the second electrode; A light emitting device, wherein the organic layer comprises an organic compound according to any one of claims 1 to 12.

15. A light-emitting device according to claim 14, a sensor, an operation button, a speaker, or a microphone; An electronic device having the

16. A light emitting apparatus comprising the light emitting device according to claim 14 and a transistor or a substrate.

17. A lighting device comprising the light-emitting device according to claim 14 and a housing.

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