Carbazole derivatives, and light-emitting elements, light-emitting devices, and electronic devices using the same

Abstract

To provide a light-emitting element having high emission efficiency and to provide a light-emitting device and an electronic device that have low power consumption and are driven at low voltage, a carbazole derivative represented by General Formula (1) is provided. In the formula, α 1 , α 2 , α 3 , and α 4 each represent an arylene group having less than or equal to 13 carbon atoms; Ar 1 and Ar 2 each represent an aryl group having less than or equal to 13 carbon atoms; R 1 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; and R 2 represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, l, m, and n each independently are 0 or 1.

Description

[0001] This application is a divisional application of the following application: Filing date: November 28, 2008; Application number: 200880126449.5 (PCT / JP2008 / 072104, 201710477630.1, 202010084186.9); Invention title: "Carbazole derivatives, light-emitting elements using carbazole derivatives, light-emitting devices, and electronic devices". This application is a divisional application of the following application: Filing date: November 28, 2008; Application number: 200880126449.5 (PCT / JP2008 / 072104, 201710477630.1, 202010084186.9); Invention title: "Carbazole derivatives, light-emitting elements using carbazole derivatives, light-emitting devices, and electronic devices". TECHNICAL FIELD

[0002] The present application relates to a carbazole derivative, a light-emitting element using the carbazole derivative, a light-emitting device, and an electronic device. BACKGROUND

[0003] In recent years, research and development of light-emitting elements utilizing electroluminescence have been actively conducted. As a basic structure of these light-emitting elements, a layer containing a light-emitting substance is interposed between a pair of electrodes. By application of voltage to the element, light emission can be obtained from the light-emitting substance.

[0004] Since such a light-emitting element is of a self-luminous type, it has advantages over liquid crystal display elements such as high visibility of pixels and no need for a backlight, and is considered to be suitable for flat panel display elements. In addition, such a light-emitting element can be made thin and lightweight, which is also an important advantage. Furthermore, a very high response speed is also a feature thereof.

[0005] In addition, since such a light-emitting element can be formed into a film form, planar light emission can be easily obtained by forming a large-area element. It is difficult to obtain this characteristic by using a point light source typified by an incandescent lamp or an LED or by using a linear light source typified by a fluorescent lamp. Thus, the above-described light-emitting element also has high practical value as a planar light source suitable for illumination and the like.

[0006] Such light-emitting elements utilizing electroluminescence are roughly classified according to whether the light-emitting substance is an organic compound or an inorganic compound. When an organic compound is used as the light-emitting substance, by application of voltage to the light-emitting element, then current passes therethrough, electrons and holes are injected from the pair of electrodes into the layer containing a light-emitting organic compound. Then, by recombination of these carriers (electrons and holes), the light-emitting organic compound is brought into an excited state, and when the excited state returns to the ground state, light is emitted.

[0007] Because of this mechanism, such a light-emitting element is called a current-excitation light-emitting element. Note that the excited state of an organic compound can be a singlet excited state or a triplet excited state. Light emitted from the singlet excited state is called fluorescence, and light emitted from the triplet excited state is called phosphorescence.

[0008] In improving the element characteristics of such light-emitting elements, there are many problems depending on the substances, and in order to solve these problems, work has been done on element structure improvement, substance development, and the like (for example, Non-Patent Document 1: Meng-Huan Ho, Yao-Shan Wu and Chin H. Chen, 2005 SID International Symposium Digest of Technical Papers, Vol. XXXVI, pp. 802-805).

[0009] In the light-emitting element described in Non-Patent Document 1, 4,4'-bis[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) is used as a layer in contact with a light-emitting layer. However, NPB has a low singlet excitation energy, and there is a possibility that energy can be transferred from a light-emitting material in an excited state. Since the energy level of the excited state is particularly high in the case of a light-emitting material that emits blue light having a short wavelength, the possibility of energy transfer to NPB is higher. Since energy is transferred to NPB, there is a problem that the light-emitting efficiency of the light-emitting element is reduced. SUMMARY

[0010] Accordingly, an object of the present application is to provide a light-emitting element having high light-emitting efficiency by providing a novel carbazole derivative. In addition, another object of the present application is to provide a light-emitting device and an electronic device that can be driven at low voltage with low power consumption.

[0011] One feature of the present application is a carbazole derivative represented by the following general formula (1)

[0012]

[0013] In the formula, α 1 , α 2 , α 3 , and α 4 each represent an arylene group having less than or equal to 13 carbon atoms which form a ring; Ar 1 and Ar 2 each represent an aryl group having less than or equal to 13 carbon atoms which form a ring; R 1 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; R 2 represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, 1, m, and n each independently are 0 or 1.

[0014] In addition, in the above structure, α 1 - α 4represented by any one of the following general formulae (2-1) to (2-12).

[0015]

[0016] In the formula, R 11 -R 16 , R 21 -R 30 , R 31 -R 38 , and R 41 -R 45 each represent any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group. R 46 and R 47 each represent any of an alkyl group having 1 to 6 carbon atoms and a phenyl group. In addition, R 46 and R 47 may be connected to each other to form a ring. R 48 each represent any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group.

[0017] In addition, in the above structure, Ar 1 and Ar 2 in general formula (1) are represented by any one of the following general formulae (3-1) to (3-6).

[0018]

[0019] In the formula, R 51 -R 56 , R 61 -R 70 , R 71 -R 78 , and R 81 -R 85 each represent any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group. R 86 and R 87 each represent any of an alkyl group having 1 to 6 carbon atoms and a phenyl group. In addition, R 86 and R 87 may be connected to each other to form a ring. R 88 and R 89 each represent any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group.

[0020] In addition, in the above structure, R 1 in general formula (1) is represented by any one of the following general formulae (4-1) to (4-9), and R 2 in general formula (1) is represented by any one of the following general formulae (4-2) to (4-9).

[0021]

[0022] In the formula, R 51 -R 70 each represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group.

[0023] Further, one feature of the present application is represented by any one of the following structural formulas (5) to (8).

[0024]

[0025]

[0026] Further, as another feature of the present application, the light-emitting element includes an EL layer between a pair of electrodes, the EL layer including at least a light-emitting layer and a hole-transport layer, at least one of the light-emitting layer and the hole-transport layer containing any of the above-described carbazole derivatives.

[0027] Further, as another feature of the present application, the light-emitting element includes an EL layer between an anode and a cathode, the EL layer including at least a light-emitting layer, a hole-transport layer, and a hole-injection layer, the hole-injection layer being in contact with the anode, at least one of the light-emitting layer, the hole-transport layer, and the hole-injection layer containing any of the above-described carbazole derivatives.

[0028] Further, in the above structure, a structure in which the hole-injection layer contains any of the above-described carbazole derivatives and an inorganic compound exhibiting an electron-accepting property with respect to the carbazole derivative can be used. Note that an oxide of a transition metal can be used as the inorganic compound. Further, as the inorganic compound, one or a plurality of titanium oxide, vanadium oxide, molybdenum oxide, tungsten oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, and silver oxide can be used.

[0029] Further, as another feature of the present application, an electronic device is formed using any of the above-described light-emitting elements.

[0030] Further, the present application also includes a light-emitting device including the above-described light-emitting element and an electronic device including the light-emitting device. The light-emitting device in this specification refers to an image display device, a light-emitting device, or a light source (including a lighting device). Further, the light-emitting device includes all of the following modules: a module in which a connector such as a flexible printed circuit (FPC), a tape automated bonding (TAB) tape, or a tape carrier package (TCP) is attached to a light-emitting element; a module having a printed wiring board at the end of a TAB tape or a TCP; and a module in which an integrated circuit (IC) is directly mounted on a light-emitting element by a chip on glass (COG) method.

[0031] Since the carbazole derivative of the present application exhibits high hole-transporting properties, it can be used mainly for a hole-transporting layer included in an EL layer of a light-emitting element. In addition, the carbazole derivative of the present application is used for forming a hole-transporting layer of a light-emitting element, whereby a light-emitting element having high emission efficiency can be formed.

[0032] In addition, a light-emitting device and an electronic device can be obtained using the light-emitting element, and they can be driven at low power consumption and at low voltage. BRIEF DESCRIPTION OF DRAWINGS

[0033] In the drawings:

[0034] FIG. 1A and 1B are cross-sectional views each showing a stack structure of a light-emitting element in Embodiment Mode 2;

[0035] FIGS. 2A-2C are cross-sectional views each showing a light-emitting mode of a light-emitting element in Embodiment Mode 2;

[0036] FIG. 3 is a cross-sectional view showing a stack structure of a light-emitting element in Embodiment Mode 3;

[0037] FIG. 4A and 4B are a top view and a cross-sectional view of an active matrix light-emitting device in Embodiment Mode 4, respectively;

[0038] FIG. 5A and 5B are a perspective view and a cross-sectional view of a passive matrix light-emitting device in Embodiment Mode 4, respectively;

[0039] FIGS. 6A-6D are views each showing an electronic device in Embodiment Mode 5;

[0040] FIG. 7 is a view showing a liquid crystal display device using a light-emitting device of the present application as a backlight;

[0041] FIG. 8 is a view showing a desk lamp using a light-emitting device of the present application;

[0042] FIG. 9 is a view showing a room illuminating device using a light-emitting device of the present application;

[0043] FIG. 10A and 10B are views showing a PCBA1BP (abbreviation) of a mobile phone; 1 a chart of H NMR spectrum;

[0044] FIG. 11A and 11Ba graph showing the absorption spectrum and emission spectrum of PCBA1BP (abbreviation) ;

[0045] FIG. 12A and 12B a graph showing the absorption spectrum and emission spectrum of PCBBi1BP (abbreviation) ; 1 a graph showing the H NMR spectrum;

[0046] FIG. 13A and 13B a graph showing the absorption spectrum and emission spectrum of PCBAF (abbreviation) ;

[0047] FIG. 14A and 14B a graph showing the H NMR spectrum of PCBAF (abbreviation) ; 1 a graph showing the H NMR spectrum;

[0048] FIG. 15A and 15B a graph showing the absorption spectrum and emission spectrum of PCBASF (abbreviation) ;

[0049] FIG. 16A and 16B a graph showing the H NMR spectrum of PCBASF (abbreviation) ; 1 a graph showing the H NMR spectrum;

[0050] FIG. 17A and 17B a graph showing the absorption spectrum and emission spectrum of PCBASF (abbreviation) ;

[0051] FIG. 18 a cross-sectional view showing the element structure of the light-emitting element in Embodiment 5;

[0052] FIG. 19 a graph showing the relationship between the current density and luminance characteristics of the light-emitting element 1 and the light-emitting element 2;

[0053] FIG. 20 a graph showing the relationship between the voltage and luminance characteristics of the light-emitting element 1 and the light-emitting element 2;

[0054] FIG. 21 a graph showing the relationship between the luminance and current efficiency characteristics of the light-emitting element 1 and the light-emitting element 2;

[0055] FIG. 22 a graph showing the relationship between the voltage and current characteristics of the light-emitting element 1 and the light-emitting element 2;

[0056] FIG. 23 a graph showing the emission spectrum of the light-emitting element 1 and the light-emitting element 2;

[0057] FIG. 24A graph showing the relationship between the current density and the luminance characteristics of the light-emitting element 1 and the light-emitting element 3;

[0058] FIG. 25 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 3;

[0059] FIG. 26 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 3;

[0060] FIG. 27 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 3;

[0061] FIG. 28 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 3;

[0062] FIG. 29 A graph showing the emission spectrum of the light-emitting element 1 and the light-emitting element 3;

[0063] FIG. 30 A graph showing the relationship between the current density and the luminance characteristics of the light-emitting element 1 and the light-emitting element 4;

[0064] FIG. 31 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 4;

[0065] FIG. 32 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 4;

[0066] FIG. 33 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 4;

[0067] FIG. 34 A graph showing the emission spectrum of the light-emitting element 1 and the light-emitting element 4;

[0068] FIG. 35 A graph showing the results of the continuous lighting test of the light-emitting element 1 and the light-emitting element 4 by constant current driving;

[0069] FIG. 36 A graph showing the relationship between the current density and the luminance characteristics of the light-emitting element 1 and the light-emitting element 5;

[0070] FIG. 37 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 5;

[0071] FIG. 38 A graph showing the relationship between the voltage and the luminance characteristics of the light-emitting element 1 and the light-emitting element 5;

[0072] FIG. 39 to show the plot of the voltage vs. current characteristics of light emitting element 1 and light emitting element 5;

[0073] FIG. 40 to show the plot of the emission spectra of light emitting element 1 and light emitting element 5;

[0074] FIG. 41 to show the plot of the CV characteristics of PCBA1BP (abbreviation);

[0075] FIG. 42 to show the plot of the CV characteristics of PCBBi1BP (abbreviation);

[0076] FIG. 43 to show the plot of the CV characteristics of PCBAF (abbreviation);

[0077] FIG. 44 to show the plot of the CV characteristics of PCBASF (abbreviation);

[0078] FIG. 45A and 45B to show the plot of the CV characteristics of PCTA1BP (abbreviation); 1 H NMR chart;

[0079] FIG. 46A and 46B to show the plot of the CV characteristics of PCTBi1BP (abbreviation); 1 H NMR chart;

[0080] FIG. 47A and 47B to show the plot of the CV characteristics of PCBANB (abbreviation); 1 H NMR chart;

[0081] FIG. 48A and 48B to show the plot of the CV characteristics of PCBNBB (abbreviation); 1 H NMR chart;

[0082] FIG. 49A and 49B to show the plot of the CV characteristics of PCBBiNB (abbreviation); 1 H NMR chart;

[0083] FIG. 50A and 50B to show the plot of the CV characteristics of PCBANT (abbreviation); 1 H NMR chart;

[0084] FIG. 51A and 51B to show the plot of the CV characteristics of BCBA1BP (abbreviation); 1A plot of H NMR spectra;

[0085] FIG. 52A and 52B A plot showing BCB ANB (abbreviation) 1 A plot of H NMR spectra;

[0086] FIG. 53A and 53B A plot showing BCB BiNB (abbreviation) 1 A plot of H NMR spectra;

[0087] FIG. 54A and 54B A plot showing NBCB AlBP (abbreviation) 1 A plot of H NMR spectra;

[0088] FIG. 55A and 55B A plot showing NCBA 1BP (abbreviation) 1 A plot of H NMR spectra;

[0089] FIG. 56 A plot showing the voltage and luminance characteristics of light emitting element 1 and light emitting elements 6-8;

[0090] FIG. 57 A plot showing the relationship between the luminance and current efficiency characteristics of light emitting element 1 and light emitting elements 6-8;

[0091] FIG. 58 A plot showing the relationship between the voltage and current characteristics of light emitting element 1 and light emitting elements 6-8;

[0092] FIG. 59 A plot showing the emission spectra of light emitting element 1 and light emitting elements 6-8;

[0093] FIG. 60 A plot showing the results of continuous lighting tests of light emitting element 1 and light emitting elements 6-8 performed by constant current driving;

[0094] FIG. 61A and 61B A plot showing PCBB i1BP III (abbreviation) 1 A plot of H NMR spectra;

[0095] FIGS. 62A-62C A plot showing PCBA 1BP IV (abbreviation) 1 A plot of H NMR spectra;

[0096] FIG. 63A and 63B A plot showing PCBNB Bβ (abbreviation) 1 A plot of H NMR spectra; and

[0097] FIG. 64A and 64B for displaying PCBBiFLP (abbreviation) 1 H NMR chart.

[0098] Best mode for carrying out the invention

[0099] Embodiment modes and embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, the present application is not limited to the description given below and various modifications can be made to the modes and details thereof without departing from the purpose and scope of the present application. Therefore, the present application should not be considered as limited to the description of the embodiment modes and embodiments given below.

[0100] [Embodiment Mode 1]

[0101] In Embodiment Mode 1, the carbazole derivative of the present application will be described.

[0102] The carbazole derivative of the present application is represented by General Formula (1).

[0103]

[0104] In the formula, α 1 , α 2 , α 3 and α 4 each represent an arylene group having less than or equal to 13 carbon atoms which form a ring; Ar 1 and Ar 2 each represent an aryl group having less than or equal to 13 carbon atoms which form a ring; R 1 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; R 2 represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In addition, 1, m and n are each independently 0 or 1.

[0105] In General Formula (1), α 1 -α 4 each represent an arylene group having less than or equal to 13 carbon atoms which form a ring. Specifically, substituents represented by Structural Formulas (2-1) to (2-12) can be given.

[0106]

[0107] In the formula, R 11 –R 16 , R 21 -R 30 , R31 -R 38 and R 41 -R 45 each represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group. R 46 and R 47 each represents any of an alkyl group having 1 to 6 carbon atoms and a phenyl group. In addition, R 46 and R 47 may be linked to each other to form a ring. R 48 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group.

[0108] In General Formula (1), Ar 1 and Ar 2 each represents an aryl group having less than or equal to 13 carbon atoms, the carbon atoms forming a ring. In particular, substituents represented by structural formulas (3-1) to (3-6) can be given.

[0109]

[0110] In the formula, R 51 -R 56 , R 61 -R 70 , R 71 -R 78 and R 81 -R 85 each represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group. R 86 and R 87 each represents any of an alkyl group having 1 to 6 carbon atoms and a phenyl group. In addition, R 86 and R 87 may be linked to each other to form a ring. R 88 and R 89 each represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group.

[0111] In General Formula (1), R 1 represents any of a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group; R 2 represents any of an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group. In particular, R 1 substituents represented by structural formulas (4-1) to (4-9) can be given, R 2 substituents represented by structural formulas (4-2) to (4-9) can be given.

[0112]

[0113] In the formula, R 51 -R 70 each represents any of a hydrogen atom, an alkyl group having 1-6 carbon atoms, a phenyl group, and a biphenyl group.

[0114] As specific examples of the carbazole derivative of the present application represented by General Formula (1), carbazole derivatives represented by Structural Formulas (9) - (425) can be given. However, the present application is not limited thereto.

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[0201]

[0202] In addition, the carbazole derivative of the present application represented by the general formula (1) can be synthesized by a synthetic method represented by the following synthetic schemes (A-1) to (A-7), the synthetic scheme (B-1), and the synthetic schemes (C-1) to (C-2).

[0203] [Synthetic method of halogenated secondary arylamine (Compound A)]

[0204] The halogenated secondary arylamine (Compound A) represented by the general formula can be synthesized in accordance with the method as shown in the following synthetic scheme (A-1). In other words, first, by halogenating the secondary arylamine (Compound Al) with a halogenating agent, the halogenated secondary arylamine (Compound A) can be obtained therefrom. Note that, as the halogenating agent, N-bromosuccinimide (NBS), N-iodosuccinimide (NIS), bromine, iodine, potassium iodide, or the like can be used.

[0205] In addition, each X 1 represents a halogen group, and is preferably bromine or iodine.

[0206]

[0207] [Synthesis method of halogenated carbazole derivative (Compound B2)]

[0208] A halogenated carbazole derivative (Compound B2) represented by the general formula can be synthesized by a method as shown in the following synthesis scheme (A-2). In other words, first, a carbazole derivative (Compound Bl) is halogenated with a halogenating agent, whereby a halogenated carbazole derivative (Compound B2) can be obtained. Note that, as the halogenating agent, N-bromosuccinimide (NBS), N-iodosuccinimide (NIS), bromine, iodine, potassium iodide, or the like can be used. In addition, each X 1 represents a halogen group, and is preferably bromine or iodine.

[0209]

[0210] [Synthesis method of compound (Compound B) in which 3-position of 9H-carbazole is substituted with organic boron of 9H-carbazole-3-boronic acid or 9H-carbazole]

[0211] A compound (Compound B) in which 3-position of 9H-carbazole is substituted with boronic acid or organic boron represented by the general formula can be synthesized by a method as shown in the following synthesis scheme (A-3). In other words, on a halogenated carbazole derivative (Compound B2), boron oxidation or organic boronation is performed with an alkyl lithium reagent and a boron reagent, whereby a compound (Compound B) in which 3-position of 9H-carbazole is substituted with boronic acid or organic boron can be obtained.

[0212] Note that, in Scheme (A-3), R 99 represents an alkyl group having 1-6 carbon atoms. R 98 represents an alkyl group having 1-6 carbon atoms. In addition, R 100 and R 101 each represent a hydrogen atom or an alkyl group having 1-6 carbon atoms. R 102 and R 103 may be connected to each other to form a ring. In addition, n-butyllithium, methyllithium, or the like can be used as the alkyl lithium reagent. Trimethyl borate, isopropyl borate, or the like can be used as the boron reagent.

[0213]

[0214] [Synthesis method of secondary aromatic amine (Compound C3)]

[0215] A secondary aromatic amine (Compound C3) represented by the general formula can be synthesized by a method as shown in the following synthesis scheme (A-4). In other words, a halogenated aryl group (Compound Cl) is coupled with a primary aromatic amine (Compound C2) with a metal catalyst in the presence of a base, whereby a secondary aromatic amine (Compound C3) can be obtained.

[0216]

[0217] In the case of performing the Buchwald-Hartwig reaction, although as the palladium catalyst usable in the synthetic scheme (A-4), bis(dibenzylideneacetone)palladium(0), palladium (II) acetate, or the like can be given, the palladium catalyst usable is not limited thereto. Although as the ligand of the palladium catalyst usable in the synthetic scheme (A-4), tri (tert-butyl) phosphine, tri (n-hexyl) phosphine, tricyclohexylphosphine, or the like can be given, the ligand usable is not limited thereto.

[0218] Although as the base usable in the synthetic scheme (A-4), an organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, or the like can be given, the base usable is not limited thereto. Further, although as the solvent usable in the synthetic scheme (A-4), toluene, xylene, benzene, tetrahydrofuran, or the like can be given, the solvent usable is not limited thereto.

[0219] The case where the Ullmann reaction is performed in the synthetic scheme (A-4) is described. In the synthetic scheme (A-4), R 104 and R 105 each represent a halogen group, an acetyl group, or the like, and as the halogen group, chlorine, bromine, and iodine can be given. It is preferable that R 104 be iodine to form cuprous iodide, or R 105 be an acetyl group to form cupric acetate. The copper compound used in the reaction is not limited thereto, and copper can be used as a substitute for the copper compound. Although as the base usable in the synthetic scheme (A-4), an inorganic base such as potassium carbonate can be given, the base usable is not limited thereto.

[0220] Although as the solvent usable in the synthetic scheme (A-4), 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (abbreviation: DMPU), toluene, xylene, benzene, or the like can be given, the solvent usable is not limited thereto. It is preferable to use DMPU or xylene having a high boiling point, because by the Ullmann reaction, when the reaction temperature is greater than or equal to 100°C, the purpose can be achieved in a shorter time and a higher yield is obtained. Since it is further preferable that the reaction temperature be greater than or equal to 150°C, it is more preferable to use DMPU.

[0221] [Method for synthesizing tertiary aromatic amine (compound C5)]

[0222] The tertiary aromatic amine (compound C5) represented by the general formula can be synthesized in accordance with the method of the following synthetic scheme (A-5). In other words, the secondary aromatic amine (compound C3) and the haloaryl group (compound C4) are coupled with a metal catalyst in the presence of a base, whereby the tertiary aromatic amine (compound C5) can be obtained.

[0223]

[0224] In the case of performing the Buchwald-Hartwig reaction, although as the palladium catalyst usable for the synthetic scheme (A-5), bis (dibenzylideneacetone) palladium (0), palladium (II) acetate, etc. can be given, the palladium catalyst usable is not limited thereto. Although as the ligand of the palladium catalyst usable for the synthetic scheme (A-5), tri (tert-butyl) phosphine, tri (n-hexyl) phosphine, tricyclohexylphosphine, etc. can be given, the ligand usable is not limited thereto.

[0225] Although as the base usable for the synthetic scheme (A-5), an organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, etc. can be given, the base usable is not limited thereto. Further, although as the solvent usable for the synthetic scheme (A-5), toluene, xylene, benzene, tetrahydrofuran, etc. can be given, the solvent usable is not limited thereto.

[0226] The case where the Ullmann reaction is performed in the synthetic scheme (A-5) is described. In the synthetic scheme (A-5), R 104 and R 105 each represent a halogen group, an acetyl group, etc., and as the halogen group, chlorine, bromine and iodine can be given. It is preferable that R 104 be iodine, forming cuprous iodide, or R 105 be an acetyl group, forming cupric acetate. The copper compound used for the reaction is not limited thereto, and copper can be used as an alternative to the copper compound. Although as the base usable for the synthetic scheme (A-5), an inorganic base such as potassium carbonate can be given, the base usable is not limited thereto.

[0227] Although as the solvent usable for the synthetic scheme (A-5), 1, 3-dimethyl-3, 4, 5, 6-tetrahydro-2 (1H) pyrimidinone (abbreviation: DMPU), toluene, xylene, benzene, etc. can be given, the solvent usable is not limited thereto. It is preferable to use DMPU or xylene having a high boiling point, because by the Ullmann reaction, the purpose can be achieved in a shorter time, and the yield is higher when the reaction temperature is greater than or equal to 100°C. Since it is further preferable that the reaction temperature be greater than or equal to 150°C, it is more preferable to use DMPU.

[0228] [Synthesis method of tertiary aromatic amine (compound C5)]

[0229] The tertiary aromatic amine (compound C5) represented by the general formula can be synthesized in the manner as shown in the following synthetic scheme (A-6). In other words, by coupling the primary aromatic amine (compound C2) and the halogenated aryl group (compounds Cl and C4) with a metal catalyst in the presence of a base, the tertiary aromatic amine (compound C5) can be obtained. However, when Ar 1 and Ar 2 are the same, β 1 and β 2 are the same, and 1 and m are the same, the compound C5 can be obtained with a high yield.

[0230]

[0231] In the case of performing the Buchwald-Hartwig reaction, although as the palladium catalyst which can be used in the synthetic scheme (A-6), bis (dibenzylideneacetone) palladium (0), palladium (II) acetate, etc. can be given, the palladium catalyst which can be used is not limited thereto. Although as the ligand of the palladium catalyst which can be used in the synthetic scheme (A-6), tri (tert-butyl) phosphine, tri (n-hexyl) phosphine, tricyclohexylphosphine, etc. can be given, the ligand which can be used is not limited thereto.

[0232] Although as the base which can be used in the synthetic scheme (A-6), an organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, etc. can be given, the base which can be used is not limited thereto. In addition, although as the solvent which can be used in the synthetic scheme (A-6), toluene, xylene, benzene, tetrahydrofuran, etc. can be given, the solvent which can be used is not limited thereto.

[0233] The case where the Ullmann reaction is performed in the synthetic scheme (A-6) is described. In the synthetic scheme (A-6), R 104 and R 105 each represent a halogen group, an acetyl group, etc., and as the halogen group, chlorine, bromine and iodine can be given. It is preferable that R 104 be iodine to form cuprous iodide, or R 105 be an acetyl group to form copper (II) acetate. The copper compound used in the reaction is not limited thereto, and copper can be used as an alternative to the copper compound. Although as the base which can be used in the synthetic scheme (A-6), an inorganic base such as potassium carbonate can be given, the base which can be used is not limited thereto.

[0234] Although as the solvent which can be used in the synthetic scheme (A-6), 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H) pyrimidinone (abbreviation: DMPU), toluene, xylene, benzene, etc. can be given, the solvent which can be used is not limited thereto. It is preferable to use DMPU or xylene having a high boiling point because by the Ullmann reaction, the purpose can be achieved in a shorter time, and the yield is higher when the reaction temperature is greater than or equal to 100°C. Since it is further preferable that the reaction temperature be greater than or equal to 150°C, it is more preferable to use DMPU.

[0235] [Method for synthesizing halogenated tertiary aromatic amine derivative (compound C)]

[0236] The halogenated tertiary aromatic amine (compound C) represented by the general formula can be synthesized by a method as shown in the following synthetic scheme (A-7). In other words, first, the tertiary aromatic amine (compound C5) is halogenated with a halogenating agent, whereby the halogenated tertiary aromatic amine (compound C) can be obtained. Note that N-bromosuccinimide (NBS), N-iodosuccinimide (NIS), bromine, iodine, potassium iodide, or the like can be used as the halogenating agent. In addition, each X 1 represents a halogen group, and is preferably bromine or iodine.

[0237]

[0238] [Synthesis method of secondary aromatic amine (compound D)]

[0239] The secondary aromatic amine (compound D) having a carbazole represented by the general formula can be synthesized by a method as shown in the following synthetic scheme (B-1). In other words, the halogenated secondary aromatic amine (compound A) and the compound (compound B) in which the 3-position of 9H-carbazole is substituted with a boronic acid or an organic boron are coupled with a metal catalyst in the presence of a base. Thereby, the secondary aromatic amine (compound D) having a carbazole can be obtained.

[0240]

[0241] In any of the above schemes, a case using a Suzuki-Miyaura reaction is described. As the palladium catalyst which can be used as the metal catalyst, palladium (II) acetate, tetrakis(triphenylphosphine)palladium (0), bis(triphenylphosphine)dichloropalladium (II), or the like can be given. As the ligand of the above palladium catalyst, tri(o-tolyl)phosphine, triphenylphosphine, tricyclohexylphosphine, or the like can be given. In addition, as the base, an organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, or the like can be given. As the solvent which can be used, a mixed solvent of toluene and water; a mixed solvent of toluene, an alcohol such as ethanol, and water; a mixed solvent of xylene and water; a mixed solvent of xylene, an alcohol such as ethanol, and water; a mixed solvent of benzene and water; a mixed solvent of benzene, an alcohol such as ethanol, and water; a mixed solvent of an ether such as ethylene glycol dimethyl ether and water; or the like can be given.

[0242] However, the catalyst, the ligand, the base, and the solvent which can be used are not limited thereto.

[0243] In addition, in any of the above schemes, a cross-coupling product of an organoaluminum, an organozirconium, an organozinc, or an organotin compound, or the like other than the arylboronic acid can be used as the base material. However, the present application is not limited thereto.

[0244] [Synthesis method of secondary aromatic amine (compound D)]

[0245] The tertiary aromatic amine having a carbazole (Compound E) represented by the general formula can be synthesized by the method as shown in the following synthetic scheme (C-1). In other words, the aromatic amine having a carbazole (Compound D) and the halogenated aryl group (Compound C4) can be coupled with a metal catalyst in the presence of a base, whereby the tertiary aromatic amine having a carbazole (Compound E) can be obtained, which is the final product.

[0246]

[0247] In any of the above schemes, a case using the Suzuki-Miyaura reaction is described. As the palladium catalyst which can be used as the metal catalyst, palladium (II) acetate, tetrakis(triphenylphosphine)palladium (0), bis(triphenylphosphine)palladium (II) dichloride, and the like can be given. As the ligand of the above palladium catalyst, tri(o-tolyl)phosphine, triphenylphosphine, tricyclohexylphosphine, and the like can be given. In addition, as the above base, an organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, and the like can be given. As the solvent which can be used, a mixed solvent of toluene and water; a mixed solvent of toluene, an alcohol such as ethanol, and water; a mixed solvent of xylene and water; a mixed solvent of xylene, an alcohol such as ethanol, and water; a mixed solvent of benzene and water; a mixed solvent of benzene, an alcohol such as ethanol, and water; a mixed solvent of an ether such as ethylene glycol dimethyl ether and water; and the like can be given.

[0248] However, the catalyst, the ligand, the base, and the solvent which can be used are not limited thereto.

[0249] In addition, in any of the above schemes, in addition to the aryl boronic acid, a cross-coupling product of an organoaluminum, an organozirconium, an organozinc, an organozirconium, an organotin, and the like can be used as the base material. However, the present application is not limited thereto.

[0250] [Another synthesis method of the tertiary aromatic amine having a carbazole (Compound E)]

[0251] The tertiary aromatic amine having a carbazole (Compound E) represented by the general formula can be synthesized by the method as shown in the following synthetic scheme (C-2). In other words, first, the halogenated tertiary aromatic amine (Compound C) and the compound in which the 3-position of 9H-carbazole is substituted with a boronic acid or an organoboron (Compound B) can be coupled with a metal catalyst in the presence of a base, whereby the tertiary aromatic amine having a carbazole (Compound E) can be obtained, which is the final product.

[0252]

[0253] [Embodiment Mode 2]

[0254] In Embodiment Mode 2, a light-emitting element formed using the carbazole derivative of the present application described in Embodiment Mode 1 is described for a hole-transport layer.

[0255] The light emitting element in Embodiment Mode 2 includes a first electrode functioning as an anode, a second electrode functioning as a cathode, and an EL layer interposed between the first electrode and the second electrode. Note that the light emitting element in Embodiment Mode 2 can obtain light emission when a voltage is applied to each of the electrodes so that the potential of the first electrode is higher than that of the second electrode.

[0256] In addition, the EL layer of the light emitting element in Embodiment Mode 2 includes a first layer (hole-injection layer), a second layer (hole-transport layer), a third layer (light-emitting layer), a fourth layer (electron-transport layer), and a fifth layer (electron-injection layer) in its structure, on the side of the first electrode.

[0257] Reference is made to FIG. 1A and 1B The structure of the light emitting element in Embodiment Mode 2 is described. A substrate 101 is used as a support of the light emitting element. For the substrate 101, for example, glass, quartz, plastic, or the like can be used.

[0258] Note that although the above substrate 101 can remain in a light emitting device or an electronic device using the light emitting element of the present application, in the manufacturing method of the light emitting element, the substrate 101 can have only a support function of the light emitting element and does not remain in the final product.

[0259] For the first electrode 102 formed on the substrate 101, a metal, an alloy, a conductive compound, a mixture thereof, or the like having a high work function (particularly, a work function of 4.0 eV or more) is preferably used. Specifically, the following examples can be given: indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), and indium oxide containing tungsten oxide and zinc oxide. In addition, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), a nitride of a metal material (e.g., titanium nitride), or the like can also be given. However, in the present application, the first layer 111 in the EL layer 103 is formed of a composite material, which is in contact with the first electrode 102 after formation, and holes can be easily injected into the composite material regardless of the work function of the first electrode 102. Thus, various known methods can be used as long as they are materials that can be used as electrode materials (e.g., also including a metal, an alloy, a conductive compound, a mixture thereof, or the like, or an element belonging to Group 1 or 2 of the periodic table).

[0260] A film of any of those materials is usually formed by a sputtering method. For example, indium zinc oxide (IZO) can be formed by a sputtering method using a target in which 1% by weight to 20% by weight of zinc oxide is added to indium oxide; and indium oxide containing tungsten oxide and zinc oxide can be formed by a sputtering method using a target in which 0.5% by weight to 5% by weight of tungsten oxide and 0.1% by weight to 1% by weight of zinc oxide are added to indium oxide. Alternatively, the first layer 111 can be formed by a vacuum evaporation method, an inkjet method, a spin coating method, or the like.

[0261] In addition, when a layer containing a composite material described below is used as a material for forming the first layer 111, the first layer 111 is in contact with the first electrode 102 in the EL layer 103 formed over the first electrode 102, and any of various materials such as a metal, an alloy, and a conductive compound; a mixture thereof; and the like can be used as a substance for the first electrode 102, regardless of their work functions. For example, aluminum (Al), silver (Ag), an aluminum-containing alloy (AlSi), or the like can also be used.

[0262] In addition, an element belonging to Group 1 or 2 of the periodic table, which is a low work function material, can also be used, i.e., an alkali metal such as lithium (Li) or cesium (Cs); an alkaline earth metal such as magnesium (Mg), calcium (Ca), or strontium (Sr); an alloy containing any of these metals (e.g., a MgAg alloy or an AlLi alloy); a rare earth metal such as europium (Eu) or ytterbium (Yb); an alloy containing such a rare earth metal; and the like.

[0263] Note that in the case where the first electrode 102 is formed using an alkali metal, an alkaline earth metal, or an alloy thereof, a vacuum evaporation method or a sputtering method can be used. Note that in the case of using a silver paste or the like, a coating method, an inkjet method, or the like can be used.

[0264] For the EL layer 103 formed over the first electrode 102, known substances can be used, and any of a low molecular compound and a macromolecular compound can be used. Note that the substance used for forming the EL layer 103 has not only a structure formed of only an organic compound but also a structure partly containing an inorganic compound.

[0265] To form the EL layer 103, a hole-injection layer containing a substance having a high hole-injection property, a hole-transport layer containing a substance having a high hole-transport property, a light-emitting layer containing a light-emitting substance, an electron-transport layer containing a substance having a high electron-transport property, an electron-injection layer containing a substance having a high electron-injection property, and the like are combined with one another and stacked as appropriate.

[0266] Note that in the case where the first electrode 102 is formed using an alkali metal, an alkaline earth metal, or an alloy thereof, a vacuum evaporation method or a sputtering method can be used. Note that in the case of using a silver paste or the like, a coating method, an inkjet method, or the like can be used. FIG. 1AIn the EL layer 103 shown, a first layer (hole-injection layer) 111, a second layer (hole-transport layer) 112, a third layer (light-emitting layer) 113, a fourth layer (electron-transport layer) 114, and a fifth layer (electron-injection layer) 115 are stacked in this order on the first electrode 102 side.

[0267] The first layer 111 as a hole-injection layer is a hole-injection layer containing a material having a high hole-injection property. As the material having a high hole-injection property, molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, manganese oxide, or the like can be used. Alternatively, as a low molecular weight organic compound, a phthalocyanine-based compound such as phthalocyanine (abbreviation: H2Pc), copper (II) phthalocyanine (abbreviation: CuPc), or vanadyl phthalocyanine (abbreviation: VOPc) can be given.

[0268] In addition, the following aromatic amine compounds, which are low molecular weight organic compounds, can also be given:

[0269] 1) 4,4',4"-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA);

[0270] 2) 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA);

[0271] 3) 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB);

[0272] 4) 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD);

[0273] 5) 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B);

[0274] 6) 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1);

[0275] 7) 3,6-di[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2);

[0276] 8) 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), and the like.

[0277] Note that the carbazole derivative of the present application described in Embodiment Mode 1 can also be used in a similar manner.

[0278] In addition, a macromolecular compound (oligomer, dendrimer, polymer, etc.) can also be used. For example, a macromolecular compound such as

[0279] 1) poly(N-vinylcarbazole) (abbreviation: PVK);

[0280] 2) poly(4-vinyltriphenylamine) (abbreviation: PVTPA),

[0281] 3) poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)isobutyleneamide] (abbreviation: PTPDMA), and

[0282] 4) poly[N,N'-di(4-butylphenyl)-N,N'-diphenylbenzidine] (abbreviation: Poly-TPD). In addition, a macromolecular compound to which an acid is added, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) or polyaniline / poly(styrenesulfonic acid) (abbreviation: PAni / PSS), can also be used.

[0283] Alternatively, for the first layer 111, a composite material in which a material having an acceptor property is contained in a material having a high hole-transport property can be used. Note that by using a material having a high hole-transport property containing a substance having an acceptor property, regardless of the work function size, a material used for forming an electrode can be selected. In other words, 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 102. Such a composite material can be formed by co-evaporation of a substance having a high hole-transport property and a substance having an acceptor property. Note that in this specification, a "composition" indicates not only a simple mixture of two materials but also a mixture of a plurality of materials in an environment where charge is given and accepted between the materials.

[0284] As the organic compound used for the composite material, various compounds such as an arylamine compound, a carbazole derivative, an aromatic hydrocarbon, and a macromolecular compound (oligomer, dendrimer, polymer, etc.) can be used. The organic compound used for the composite material is preferably an organic compound having a high hole-transport property. In particular, it is preferable to use a substance having a hole mobility of 10 -6 cm 2 or higher. However, a substance different from the above can be used as long as the hole-transport property of the substance is higher than the electron-transport property. The organic compound that can be used for the composite material is specifically shown below.

[0285] Organic compounds for use in the composite material can be given, such as arylamine compounds, for example MTDATA, TDATA, DPAB, DNTPD, DPA3B, PCzPCA1, PCzPCA2, PCzPCN1, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), and N,N'-di(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD); and carbazole derivatives, for example 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tri[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (abbreviation: CzPA), and 1,4-di[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene. Note that the carbazole derivatives of the present application described in Embodiment Mode 1 can also be used in a similar manner.

[0286] Further, the following aromatic hydrocarbon compounds can be given:

[0287] 1) 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA);

[0288] 2) 2-tert-butyl-9,10-di(1-naphthyl)anthracene;

[0289] 3) 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA);

[0290] 4) 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA);

[0291] 5) 9,10-di(2-naphthyl)anthracene (abbreviation: DNA);

[0292] 6) 9,10-diphenylanthracene (abbreviation: DPAnth);

[0293] 7) 2-tert-butylanthracene (abbreviation: t-BuAnth);

[0294] 8) 9,10-di(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA);

[0295] 9) 9,10-di[2-(1-naphthyl)phenyl]-2-tert-butyl-anthracene;

[0296] 10) 9,10-di[2-(1-naphthyl)phenyl]anthracene;

[0297] 11) 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, and the like.

[0298] Further, the following aromatic hydrocarbon compounds can be given:

[0299] 1) 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene;

[0300] 2) 9,9'-bianthracene;

[0301] 3) 10,10'-diphenyl-9,9'-bianthracene;

[0302] 4) 10,10'-di(2-phenylphenyl)-9,9'-bianthracene;

[0303] 5) 10,10'-di[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthracene;

[0304] 6) anthracene;

[0305] 7) tetracene;

[0306] 8) rubrene;

[0307] 9) perylene;

[0308] 10) 2,5,8,11-tetra(t-butyl)perylene;

[0309] 11) pentacene;

[0310] 12) hexacene;

[0311] 13) 4,4'-di(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi);

[0312] 14) 9,10-di[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA), and the like.

[0313] As the substance having an acceptor property, an organic compound such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ) and p-tetrachlorobenzoquinone, and an oxide of a transition metal can be given. Further, an oxide of a metal belonging to Groups 4 to 8 of the periodic table can be given. In particular, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron-accepting property. Among them, molybdenum oxide is particularly preferable because it is stable in air and has low hygroscopic property, so that it can be easily handled.

[0314] Note that a composite material formed using the above macromolecular compound such as PVK, PVTPA, PTPDMA, or polyTPD and the above substance having an acceptor property can be used for the first layer 111. Note that a composite material formed by combining the inventive carbazole derivative described in Embodiment Mode 1 and the above substance having an acceptor property can also be used for the first layer 111.

[0315] The second layer 112, which is a hole-transport layer, is a hole-transport layer containing a substance having high hole-transport properties. Note that the inventive carbazole derivative described in Embodiment Mode 1 is used for the second layer 112 in Embodiment Mode 2.

[0316] In addition, the inventive carbazole derivative described in Embodiment Mode 1 can also be used for the first layer 111 and the second layer 112. In that case, an element can be easily manufactured, and the material usage efficiency can be improved. In addition, since the energy diagrams of the first layer 111 and the second layer 112 are the same or similar, carriers can be easily transported between the first layer 111 and the second layer 112.

[0317] The third layer 113 is a light-emitting layer containing a substance having high light-emitting properties. For the third layer 113, any of the low molecular weight organic compounds given below can be used.

[0318] As a light-emitting substance for emitting blue light, N,N'-di[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbazene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), and the like can be given.

[0319] As a light-emitting substance for emitting green light, the following can be given:

[0320] 1) N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA);

[0321] 2) N-[9,10-di(l,l'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA);

[0322] 3) N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-l,4-diaminobenzene (abbreviation: 2DPAPA);

[0323] 4) N-[9,10-di(l,l'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-l,4-diaminobenzene (abbreviation: 2DPABPhA);

[0324] 5) N-[9,10-di(l,l'-biphenyl-2-yl)]-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA);

[0325] 6) N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), and the like.

[0326] Examples of luminescent materials emitting yellow light include rubrene and 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetraphenyl (abbreviation: BPT). Examples of luminescent materials emitting red light include N,N,N',N'-tetra(4-methylphenyl)tetraphenyl-5,11-diamine (abbreviation: p-mPhTD) and 7,13-diphenyl-N,N,N',N'-tetra(4-methylphenyl)acenaphthene[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD).

[0327] Furthermore, the third layer 113 may have a structure in which the above-mentioned substances with high luminescence properties are dispersed in another substance. Note that, in the case of dispersion, the concentration of the substance to be dispersed is preferably set to 20% (by mass) or less of the total amount. Alternatively, a known substance may be used as the substance in which the luminescent substance is dispersed. Preferably, the substance is used in which the lowest unoccupied molecular orbital level (LUMO level) is deeper (in absolute value) than that of the luminescent substance, and the highest occupied molecular orbital level (HOMO level) is shallower (in absolute value) than that of the luminescent substance.

[0328] In particular, any of the following metal complexes can be used:

[0329] 1) Tris(8-hydroxyquinolinolato) aluminum(III) (abbreviation: Alq);

[0330] 2) Tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviation: Almq3);

[0331] 3) Bis(10-hydroxybenzo[h]quinolinato) beryllium(II) (abbreviation: BeBq2);

[0332] 4) Bis(2-methyl-8-hydroxyquinoline)(4-phenylphenolato)aluminum(III) (abbreviation: BA1q);

[0333] 5) Bis(8-hydroxyquinoline) zinc(II) (abbreviation: Znq);

[0334] 6) Bis[2-(2-benzo[]] Zinc(II)-(ZnPBO)-(ZnPBO)

[0335] 7) Bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviation: ZnBTZ), etc.

[0336] Alternatively, any of the following heterocyclic compounds may be used:

[0337] 1) 2-(biphenyl-4-yl)-5-(4-tert-butylphenyl)-1,3,4- PBD (diazole);

[0338] 2) 1,3-Bis[5-(p-tert-butylphenyl)-1,3,4- [Diazol-2-yl]benzene (abbreviation: OXD-7);

[0339] 3) 3-(biphenyl-4-yl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ);

[0340] 4) 2,2',2"-(1,3,5-benztriphenylmethyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI);

[0341] 5) Red phenanthrene (abbreviation: BPhen);

[0342] 6) Copper Bath (BCP), etc.

[0343] Alternatively, any of the following fused aromatic compounds may be used:

[0344] 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviation: CzPA);

[0345] 3,6-Diphenyl-9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviation: DPCzPA);

[0346] 9,10-Di(3,5-diphenylphenyl)anthracene (abbreviation: DPPA);

[0347] 9,10-Di(2-naphthyl)anthracene (abbreviation: DNA);

[0348] 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviation: t-BuDNA);

[0349] 9,9'-Bantane (abbreviation: BANT);

[0350] 9,9'-(dimethylstyrene-3,3'-dimethyl)bifenylphenanthrene (abbreviation: DPNS);

[0351] 9,9'-(diphenyl styrene-4,4'-dimethyl)bifenyl styrene (abbreviation: DPNS2);

[0352] 3,3',3"-(benzene-1,3,5-triphenylmethyl)tripyrene (abbreviation: TPB3), etc.

[0353] As the substance in which the substance having the light emitting property is dispersed, various substances can be used. For example, in order to suppress crystallization, a substance for suppressing crystallization of rubrene and the like can also be added. In addition, NPB, Alq and the like can also be added to efficiently transfer energy to the substance having the light emitting property. Thus, since there is a structure in which the substance having the high light emitting property is dispersed in another substance, crystallization of the third layer 113 can be suppressed. In addition, concentration quenching due to a high concentration of the substance having the high light emitting property can be suppressed.

[0354] In addition, among the above substances, a substance having an electron transporting property is particularly preferably used so that the substance having the light emitting property is dispersed therein to form the third layer 113. In particular, any of the above metal complexes and heterocyclic compounds; CzPA, DNA and t-BuDNA among the above fused aromatic compounds; and other macromolecular compounds given below can also be used as the substance usable for the fourth layer 114.

[0355] Alternatively, for the third layer 113, the following macromolecular compounds can be used.

[0356] As the light emitting substance emitting blue light, the following can be given:

[0357] poly(9,9-dioctylfluorene-2,7-diyl) (abbreviation: POF),

[0358] [(9,9-dioctylfluorene-2,7-diyl)-(2,5-dimethoxybenzene-1,4-diyl)] copolymer (abbreviation: PF-DMOP),

[0359] {(9,9-dioctylfluorene-2,7-diyl)-[N,N'-di(p-t-butylphenyl)-1,4-diaminobenzene]} copolymer (abbreviation: TAB-PFH), and the like.

[0360] As the light emitting substance emitting green light, the following can be given:

[0361] poly(p-phenylenevinylene) (abbreviation: PPV),

[0362] [(9,9-dihexylfluorene-2,7-diyl)-(benzo[2,1,3]thiadiazole-4,7-diyl)] alt-copolymer (abbreviation: PFBT),

[0363] [(9,9-dioctyl-2,7-divinylenefluorenylene)-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene)] alt-copolymer, and the like.

[0364] As the light emitting substance emitting orange-red light, the following can be given:

[0365] Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (abbreviation: MEH-PPV),

[0366] Poly(3-butylthiophene-2,5-diyl) (abbreviation: R4-PAT),

[0367] {[9,9-dihexyl-2,7-di(1-cyanovinylene)fluorenyl]-[2,5-di(N,N'-diphenylamino)-1,4- phenylene]} alternating copolymer,

[0368] {[2-methoxy-5-(2-ethylhexyloxy)-1,4-di(1-cyanovinylene phenylene)]-[2,5-di(N,N'- diphenylamino)-1,4-phenylene]} alternating copolymer (abbreviation: CN-PPV-DPD), and the like.

[0369] The fourth layer 114 is an electron-transport layer, and contains a substance having a high electron-transport property. For the fourth layer 114, a metal complex such as Alq, Almq3, BeBq2, BAlq, Znq, ZnPBO, or ZnBTZ, or the like, which is a low molecular weight organic compound, can be used, for example. Alternatively, a heterocyclic compound such as PBD, OXD-7, TAZ, TPBI, BPhen, or BCP can be used instead of the metal complex. The substance described herein is mainly a substance having an electron mobility of 10 -6 cm 2 or more. Note that another substance can be used for the electron-transport layer as long as the electron-transport property of the substance is higher than its hole-transport property, in addition to the above substances. Further, the electron-transport layer is not limited to a single layer, but can be a stacked layer of two or more layers formed of the above substances.

[0370] Alternatively, for the fourth layer 114, a macromolecular compound can be used. For example, [(9,9-dihexylfluorene-2,7-diyl)-(pyridine-3,5-diyl)] copolymer (abbreviation: PF-Py), [(9,9-dioctylfluorene-2,7-diyl)-(2,2'-bipyridine-6,6'-diyl)] copolymer (abbreviation: PF-BPy), or the like can be used.

[0371] Further, the fifth layer 115 is an electron-injection layer, and contains a substance having a high electron-injection property. For the fifth layer 115, an alkali metal, an alkaline earth metal, or a compound thereof such as lithium fluoride (LiF), cesium fluoride (CsF), or calcium fluoride (CaF2) can be used. Alternatively, a layer formed of a substance having an electron-transport property, which contains an alkali metal, an alkaline earth metal, or a compound thereof, can be used, particularly, a layer formed of Alq containing magnesium (Mg) or the like. Note that in this case, electrons can be more efficiently injected from the second electrode 104.

[0372] For the second electrode 104, metals, alloys, conductive compounds, mixtures thereof, etc., with low work function (especially 3.8 eV or lower) can be used. Specific examples of such cathode materials include elements belonging to Group 1 or 2 of the periodic table, i.e., alkali metals such as lithium (Li) or cesium (Cs); alkaline earth metals such as magnesium (Mg), calcium (Ca), or strontium (Sr); alloys containing any of these metals (e.g., MgAg alloys or AlLi alloys); rare earth metals such as europium (Eu) or ytterbium (Yb); alloys containing such rare earth metals, etc.

[0373] Note that when the second electrode 104 is formed using alkali metals, alkaline earth metals, or their alloys, vacuum evaporation or sputtering methods can be used. Note that when using silver paste, coating methods, inkjet printing, etc., can be used.

[0374] Note that by providing the fifth layer 115, the second electrode 104 can be formed using any kind of conductive material, such as Al, Ag, ITO, and silicon-containing or silicon-oxide-containing indium tin oxide, regardless of their work function. These conductive materials can be formed by sputtering, inkjet printing, spin coating, etc.

[0375] Furthermore, as a method for forming the EL layer 103, the first layer (hole injection layer) 111, the second layer (hole transport layer) 112, the third layer (light emission layer) 113, the fourth layer (electron transport layer) 114, and the fifth layer (electron injection layer) 115 are stacked sequentially, and any method of various types can be used, whether the method is dry or wet. For example, vacuum evaporation, inkjet printing, spin coating, etc., can be used. Note that different formation methods can be used for each layer.

[0376] In addition to dry methods such as sputtering or vacuum evaporation, the second electrode 104 can also be formed by wet methods such as sol-gel, using a metal material paste.

[0377] In the light-emitting element of the present invention described above, light is emitted due to the current flow caused by the potential difference formed between the first electrode 102 and the second electrode 104, and the recombination of holes and electrons in the EL layer 103. The emitted light is then extracted externally through one or both of the first electrode 102 and the second electrode 104. Therefore, one or both of the first electrode 102 and the second electrode 104 are electrodes with light-transmitting properties.

[0378] Note that when only the first electrode 102 is a light-transmitting electrode, such as FIG. 2A As shown, light emitted by the EL layer 103 is extracted from one side of the substrate 101 via the first electrode 102. Alternatively, when only the second electrode 104 is an electrode with light-transmitting properties, as... FIG. 2BAs shown, light emitted by the EL layer 103 is extracted to the side of the substrate 101 and the opposite side of the substrate 101 through the first electrode 102 and the second electrode 104. FIG. 2C As shown, light emitted by the EL layer 103 is extracted to the side of the substrate 101 and the opposite side of the substrate 101 through the first electrode 102 and the second electrode 104.

[0379] The structure in which the layers are provided between the first electrode 102 and the second electrode 104 is not limited to the above. A structure other than the above can be used, as long as at least the second layer 112 hole-transport layer and the third layer 113 light-emitting layer are included.

[0380] Alternatively, as shown, FIG. 1B the second electrode 104 functioning as a cathode, the EL layer 103, and the first electrode 102 functioning as an anode can be stacked in this order on the substrate 101. Note that in this case, the EL layer 103 has a structure in which the fifth layer 115, the fourth layer 114, the third layer 113, the second layer 112, the first layer 111, and the first electrode 102 are stacked in this order on the second electrode 104.

[0381] Note that by using the light-emitting element of the present application, a passive matrix light-emitting device or an active matrix light-emitting device in which the drive of the light-emitting element is controlled by a thin film transistor (TFT) can be manufactured.

[0382] Note that in the case of manufacturing an active matrix light-emitting device, the structure of the TFT is not particularly limited. For example, an interlaced TFT or an inverted interlaced TFT can be used as appropriate. In addition, an excitation circuit formed over a TFT substrate can be formed of an n-type TFT and a p-type TFT or only an n-type TFT or a p-type TFT. Further, the crystallinity of a semiconductor film used for the TFT is not particularly limited. Either an amorphous semiconductor film or a crystalline semiconductor film can be used for the TFT.

[0383] Since the second layer (hole-transport layer) 112 is formed of the carbazole derivative of the present application in the light-emitting element, the light-emitting element of Embodiment Mode 2 is shown, so that not only improvement in element efficiency but also suppression of an increase in drive voltage can be achieved.

[0384] Note that Embodiment Mode 2 can be combined with any of the structures described in Embodiment Mode 1 as appropriate.

[0385] [Embodiment Mode 3]

[0386] In Embodiment Mode 3, reference is made to FIG. 1A. FIG. 3described in any of the light-emitting elements in Embodiment Mode 2 (hereinafter referred to as a stacked light-emitting element). This light-emitting element is a stacked light-emitting element having a plurality of EL layers (a first EL layer 303 and a second EL layer 304) between a first electrode 301 and a second electrode 302. Note that although a two-EL-layer structure is described in Embodiment Mode 3, a three- or more-EL-layer structure can also be used.

[0387] In Embodiment Mode 3, the first electrode 301 functions as an anode and the second electrode 302 functions as a cathode. Note that for the first electrode 301 and the second electrode 302, structures similar to those described in Embodiment Mode 1 can be used. In addition, for the plurality of EL layers (the first EL layer 303 and the second EL layer 304), structures similar to those described in Embodiment Mode 2 can be used. Note that the structures of the first EL layer 303 and the second EL layer 304 can be the same as or different from each other, and can be similar to those described in Embodiment Mode 2.

[0388] In addition, a charge generation layer 305 is provided between the plurality of EL layers (the first EL layer 303 and the second EL layer 304). When a voltage is applied to the first electrode 301 and the second electrode 302, the charge generation layer 305 has a function of injecting electrons into one of the EL layers and injecting holes into the other EL layer. In Embodiment Mode 3, when a voltage is applied so that the potential of the first electrode 301 is higher than that of the second electrode 302, the charge generation layer 305 injects electrons into the first EL layer 303 and injects holes into the second EL layer 304.

[0389] Note that the charge generation layer 305 preferably has a light-transmitting property in terms of light extraction efficiency. In addition, the charge generation layer 305 functions even when its conductivity is lower than that of the first electrode 301 or the second electrode 302.

[0390] The charge generation layer 305 can have a structure in which a substance having an acceptor property is added to a substance having a high hole-transport property, or a structure in which a substance having a donor property is added to a substance having a high electron-transport property. Alternatively, these two structures can be stacked together.

[0391] In the case of using a structure in which a substance having an acceptor property is added to a substance having a high hole-transport property, as the substance having a high hole-transport property, for example, an arylamine compound such as 4,4'-di[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-di(3-methylphenyl)-N,N'-diphenyl-[l,r-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4"-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), or 4,4'-di[N-(spiro-9',9'-bifluorene-2-yl)-N-phenylamino]-l,r-biphenyl (abbreviation: BSPB) can be used. The substance described here is mainly a substance having a hole mobility of greater than or equal to 10 -6 cm 2 Vs. Note that a substance other than the above-described substances can also be used as long as it has a hole-transport property higher than an electron-transport property.

[0392] In addition, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, or the like can be given as a substance having an acceptor property. In addition, a transition metal oxide can also be given. In addition, an oxide of a metal belonging to Groups 4 to 8 in the periodic table can be given. In particular, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferable because of their high electron-accepting property. Among them, molybdenum oxide is particularly preferable because it is stable in the air and easy to handle due to its low hygroscopic property.

[0393] In another aspect, in the case of using a structure in which a substance having a donor property is added to a substance having a high electron-transport property, as the substance having a high electron-transport property, for example, a metal complex having a quinoline skeleton or a benzoquinoline skeleton, such as tris(8-hydroxyquinolinate)aluminum (III) (abbreviation: Alq), tris(4-methyl-8-quinolinate)aluminum (III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinate)beryllium (II) (abbreviation: BeBq2), or bis(2-methyl-8-quinolinate)(4-phenylphenolate)aluminum (III) (abbreviation: BAIq) can be used. In addition, a metal complex having an oxazole-based ligand or a thiazole-based ligand, such as bis[2-(2'-hydroxyphenyl)benzo ​Benzoxazolato)] zinc (II) (abbreviation: Zn(BOX)2) or bis[2-(2'-hydroxyphenyl)benzothiazolato)] zinc (II) (abbreviation: Zn(BTZ)2) can also be used. In addition, any of the following compounds can also be used in place of the metal complex: 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4- oxadiazole (abbreviation: PBD); 1,3-bis[5-(p-tert-butylphenyl)-1,3,4- oxadiazol-2-yl]benzene (abbreviation: OXD-7); 3-(4-biphenyl)-4-phenyl-5-(4-tert- butylphenyl)-1,2,4-triazole (abbreviation: TAZ); bathophenanthroline (abbreviation: BPhen); bathocuproin (BCP); and the like. The substances described here are mainly substances having an electron mobility of 10 -6 cm 2 Vs or more. Note that a substance other than the above substances can be used as long as the substance has an electron-transport property higher than a hole-transport property.

[0394] In addition, for a substance having a donor property, an alkali metal, an alkaline earth metal, a rare earth metal, a metal belonging to Group 13 of the periodic table, or an oxide or carbonate thereof can be used. Lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, and the like are particularly preferable. Alternatively, an organic compound such as tetrathianaphthacene can be used as a substance having a donor property.

[0395] Note that by forming the charge generation layer 305 using any of the above materials, an increase in driving voltage can be suppressed in the case of EL layer stacking.

[0396] Although a light-emitting element having two EL layers is described in Embodiment Mode 3, the present application can be similarly applied to a light-emitting element in which three or more EL layers are stacked. As with the light-emitting element of Embodiment Mode 3, by arranging a plurality of EL layers apart from each other with a charge generation layer positioned between a pair of electrodes, a long-life element can be obtained in a high-brightness region while maintaining a low current density. As an application example, in the case where a light-emitting element is applied to lighting, a voltage drop due to resistance of an electrode material can be reduced. Thus, light can be emitted uniformly over a large area. In addition, a light-emitting device with low power consumption and driven at a low voltage can be obtained.

[0397] In addition, when the EL layer has different emission colors, the desired emission color can be obtained by the full light-emitting element. For example, in a light-emitting element having two EL layers, when the emission color of the first EL layer and the emission color of the second EL layer are made complementary colors, a light-emitting element that emits white light can also be obtained as a full light-emitting element. Note that "complementary colors" indicates a relationship between colors, in which the colors become achromatic colors when they are mixed. That is, white light emission can be obtained by mixed light from substances that emit complementary colors of light.

[0398] In a light-emitting element having three EL layers, for example, when the emission color of the first EL layer is red, the emission color of the second EL layer is green, and the emission color of the third EL layer is blue, a light-emitting element that emits white light can also be similarly obtained as a full light-emitting element.

[0399] Note that Embodiment Mode 3 can be combined with any of the structures described in Embodiment Modes 1 and 2 as appropriate.

[0400] [Embodiment Mode 4]

[0401] In Embodiment Mode 4, a light-emitting device having the light-emitting element of the present application in a pixel portion is described with reference to FIG. 4A and 4B FIG. 4A is a top view of the light-emitting device, FIG. 4B is a cross-sectional view taken along FIG. 4A in A-A' and B-B'.

[0402] In FIG. 4A , dotted reference numerals 401, 402, and 403 represent an excitation circuit portion (source excitation circuit), a pixel portion, and an excitation circuit portion (gate excitation circuit), respectively. Reference numerals 404 and 405 represent a sealing base and a sealing agent, respectively, and the inside region enclosed by the sealing agent 405 is a space 407.

[0403] A lead wire 408 is a line for transmitting an input signal to the source excitation circuit portion 401 and the gate excitation circuit 403, and receiving a video signal, a clock signal, a start signal, a timing signal, and the like from a flexible printed circuit (FPC) 409 serving as an external input terminal. Although only the FPC is shown here, the FPC can be provided with a printed wiring board (PWB). Note that the light-emitting device in this specification includes not only the light-emitting device itself but also the light-emitting device attached to a FPC or a PWB.

[0404] Then, a light-emitting device having the light-emitting element of the present application in a pixel portion is described with reference to FIG. 4B ​A cross-sectional structure of a light emitting device is described. An exciting circuit portion and a pixel portion are formed over an element substrate 410. One pixel in the display pixel portion 402 and a source exciting circuit 401 which is an exciting circuit portion are shown here. A CMOS circuit obtained by combining an n-channel TFT 423 and a p-channel TFT 424 is formed as the source exciting circuit 401. The exciting circuit can be formed by various CMOS circuits, PMOS circuits or NMOS circuits. In Embodiment Mode 4, although a driver-integrated structure in which the exciting circuit is formed over the substrate is described, the exciting circuit is not necessarily formed over the substrate but can be formed outside the substrate.

[0405] The pixel portion 402 is formed of a plurality of pixels having a switching TFT 411, a current control TFT 412 and a first electrode 413 electrically connected to the drain of the current control TFT 412. An insulator 414 is formed to cover the end portion of the first electrode 413.

[0406] The insulator 414 is preferably formed so as to have a curved surface on which the end portion or the lower end portion is curved to obtain favorable coverage. For example, by using a positive photosensitive acrylic as a material of the insulator 414, the insulator 414 having a curved surface having a radius of curvature (0.2 μm to 3 μm) only at the upper end portion can be formed. Further, a negative photosensitive material which becomes insoluble in an etchant by light irradiation or a positive photosensitive material which becomes soluble in an etchant by light irradiation can be used as the insulator 414.

[0407] An EL layer 416 and a second electrode 417 are formed over the first electrode 413. Here, the first electrode 413 can be formed of any of various materials such as a metal, an alloy and a conductive compound or a mixture thereof. Note that as a specific material, the material shown in Embodiment Mode 2 can be used as a material which can be used for the first electrode.

[0408] Further, the EL layer 416 is formed by any of various methods such as an evaporation method using an evaporation mask, an inkjet method or a spin coating method. The EL layer 416 has the structure described in Embodiment Mode 2. A low molecular weight compound or a macromolecular compound (including an oligomer or a dendrimer) can be used as another material contained in the EL layer 416. An inorganic compound as well as an organic compound can also be used as a material of the EL layer.

[0409] As the material of the second electrode 417, any of various metals, alloys, and electrically conductive compounds or mixtures thereof can be used. In the case where the second electrode 417 is used as a cathode, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a low work function (3.8 eV or less) is preferably used. For example, an element belonging to Group 1 or 2 of the periodic table, i.e., an alkali metal such as lithium (Li) or cesium (Cs); an alkaline earth metal such as magnesium (Mg), calcium (Ca), or strontium (Sr), or an alloy containing any of these metals (e.g., a MgAg alloy or an AlLi alloy); or the like can be given.

[0410] Note that in the case where light generated in the EL layer 416 is transmitted through the second electrode 417, a metal thin film having a reduced thickness and a stack of a transparent conductive film (indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO), or indium oxide containing tungsten oxide and zinc oxide, etc.) can also be used for the second electrode 417.

[0411] By attaching the sealing substrate 404 and the element substrate 410 with the sealing agent 405, a structure is obtained in which the light-emitting element 418 is provided in a space 407 surrounded by the element substrate 410, the sealing substrate 404, and the sealing agent 405. Note that the space 407 is filled with a filler such as an inert gas (e.g., nitrogen, argon, or the like) or the sealing agent 405.

[0412] An epoxy-based resin is preferably used as the sealing agent 405. In addition, a material that does not transmit moisture and oxygen as much as possible is preferably used. A plastic substrate formed of FRP (fiber-reinforced plastic), PVF (polyvinyl fluoride), polyester, acrylic, or the like, as well as a glass substrate or a quartz substrate can be used as the material of the sealing substrate 404.

[0413] As described above, an active matrix light-emitting device including the light-emitting element of the present application can be obtained.

[0414] In addition, the light-emitting element of the present application can be used for a passive matrix light-emitting device in addition to the above active matrix light-emitting device. FIG. 5A and 5B A perspective view and a cross-sectional view of a passive matrix light-emitting device using the light-emitting element of the present application are shown. Note that FIG. 5A is a perspective view of a light-emitting device, FIG. 5B is FIG. 5A is a cross-sectional view taken along the line X-Y.

[0415] In FIG. 5A and 5BIn the embodiment, the EL layer 504 is provided between the first electrode 502 and the second electrode 503 over the substrate 501. The edge portion of the first electrode 502 is covered with the insulating layer 505. Then, the partition layer 506 is provided over the insulating layer 505. The side wall of the partition layer 506 has a slope so that the distance between one side and the other side becomes narrower as the side wall approaches the substrate surface. In other words, the cross section of the partition layer 506 in the short side direction is a trapezoid, and the lower base (the side facing the direction similar to the planar direction of the insulating layer 505 and in contact with the insulating layer 505) is shorter than the upper base (the side facing the direction similar to the planar direction of the insulating layer 505 but not in contact with the insulating layer 505). By providing the partition layer 506 in this manner, defects of the light emitting element due to static electricity or the like can be prevented.

[0416] By the above method, a passive matrix light emitting device using the light emitting element of the present application can be obtained.

[0417] Note that any light emitting device (active matrix light emitting device and passive matrix light emitting device) described in Embodiment Mode 4 is formed using the light emitting element of the present application having high emission efficiency, so that a light emitting device with reduced power consumption is obtained.

[0418] Note that Embodiment Mode 4 can be combined with any of the structures described in Embodiment Modes 1 to 3 as appropriate.

[0419] [Embodiment Mode 5]

[0420] In Embodiment Mode 5, an electronic device including the light emitting device of the present application described in Embodiment Mode 4 as a part thereof is described. Examples of the electronic device include a camera such as a video camera or a digital camera, a goggle display, a navigation system, a sound reproduction apparatus (e.g., a car audio system and an audio component), a computer, a game machine, a portable information terminal (e.g., a portable computer, a mobile phone, a portable game machine, and an electronic book), an image reproduction apparatus in which a recording medium is provided (particularly, an apparatus capable of reproducing a recording medium such as a digital versatile disc (DVD) and an apparatus equipped with a display unit in which an image can be displayed), and the like. Specific examples of these electronic devices are shown in FIGS. 6A-6D

[0421] FIG. 6A A television set of the present application is described, which includes a housing 611, a support base 612, a display portion 613, a speaker portion 614, a video input terminal 615, and the like. In the television set, the light emitting device of the present application can be applied to the display portion 613. Since the light emitting device of the present application has the feature of high emission efficiency, a television set with reduced power consumption can be obtained by applying the light emitting device of the present application.

[0422] ​FIG. 6B A computer of the present application is shown, which includes a main body 621, a housing 622, a display portion 623, a keyboard 624, an external connection port 625, a pointing device 626, and the like. In this computer, the light emitting device of the present application can be applied to the display portion 623. Since the light emitting device of the present application has a feature of high emission efficiency, a computer with reduced power consumption can be obtained by applying the light emitting device of the present application.

[0423] FIG. 6C A mobile phone of the present application is shown, which includes a main body 631, a housing 632, a display portion 633, an audio input portion 634, an audio output portion 635, operation keys 636, an external connection port 637, an antenna 638, and the like. In this mobile phone, the light emitting device of the present application can be applied to the display portion 633. Since the light emitting device of the present application has a feature of high emission efficiency, a mobile phone with reduced power consumption can be obtained by applying the light emitting device of the present application.

[0424] FIG. 6D A camera of the present application is shown, which includes a main body 641, a display portion 642, a housing 643, an external connection port 644, a remote control reception portion 645, an image reception portion 646, a battery 647, an audio input portion 648, operation keys 649, an eyepiece portion 650, and the like. In this camera, the light emitting device of the present application can be applied to the display portion 642. Since the light emitting device of the present application has a feature of high emission efficiency, a camera with reduced power consumption can be obtained by applying the light emitting device of the present application.

[0425] As described above, the light emitting device of the present application has such a wide range of applications that it can be applied to electronic devices in various fields.

[0426] The light emitting device of the present application can be used as an illumination device. FIG. 7 As an example of a liquid crystal display device, the light emitting device of the present application is used as a backlight. FIG. 7 A liquid crystal display device of the present application is shown, which includes a housing 701, a liquid crystal layer 702, a backlight 703, and a housing 704. The liquid crystal layer 702 is connected to a driver IC 705. The light emitting device of the present application is used for the backlight 703, and a current is supplied through a terminal 706.

[0427] Since the light emitting device of the present application is used as a backlight of the above-described liquid crystal display device, a backlight with low power consumption can be obtained. In addition, since the light emitting device of the present application is a planar light emitting device and can be enlarged in area, the backlight can also have a large area. Thus, a liquid crystal display device with a large area and low power consumption can be obtained.

[0428] FIG. 8 As a table lamp, an example of a use of the light emitting device of the present application is shown. FIG. 8The desk lamp shown in FIG. 8 has a housing 801 and a light source 802, and the light emitting device of the present application is used as the light source 802. The light emitting device of the present application has a light emitting element with high light emission efficiency, and thus can be used as a desk lamp with low power consumption.

[0429] FIG. 9 As the indoor lighting device 901, an example using the light emitting device of the present application is shown. Since the area of the light emitting device of the present application can also be enlarged, the light emitting device of the present application can be used as a lighting device with a large area. In addition, the light emitting device of the present application has a light emitting element with high light emission efficiency, and thus can be used as a lighting device with low power consumption. When FIG. 6A The television set 902 described in FIG. 9 is placed in a room where the light emitting device of the present application is used as the indoor lighting device 901, and public broadcasting and movies can be watched.

[0430] Note that the embodiment mode 5 can be combined with any of the structures described in the embodiment modes 1 to 4 as appropriate.

[0431] [Embodiment 1]

[0432] In the embodiment 1, a method for synthesizing the carbazole derivative of the present application represented by Structural Formula (5), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBA1BP), will be specifically described.

[0433]

[0434] [Step 1: Synthesis of 4-bromo-diphenylamine]

[0435] A synthesis scheme of 4-bromo-diphenylamine in Step 1 is shown in the following (D-1).

[0436]

[0437] In a 1-L Erlenmeyer flask, 51 g (0.3 mol) of diphenylamine was dissolved in 700 mL of ethyl acetate, and then 54 g (0.3 mol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. After about 300 hours, the mixture solution was washed with water, and then magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the filtrate was concentrated to collect. Thus, 70 g of the target product was obtained as a dark brown oil at a yield of 94%.

[0438] [Step 2-1: Synthesis of 3-bromo-9-phenyl-9H-carbazole]

[0439] A synthesis scheme of 3-bromo-9-phenyl-9H-carbazole in Step 2-1 is shown in the following (D-2-1).

[0440]

[0441] In a 1000 mL conical flask, 24 g (100 mmol) of 9-phenyl-9H-carbazole, 18 g (100 mmol) of N-bromosuccinimide, 450 mL of toluene and 200 mL of ethyl acetate were added, and the mixture was stirred at room temperature for 45 hours. The suspension was washed with water, and then magnesium sulfate was added thereto to remove moisture. The suspension was filtered, and the obtained filtrate was concentrated and dried. Thus, 32 g of the target product 3-bromo-9-phenyl-9H-carbazole in the form of caramel was obtained at a yield of 99%.

[0442] [Step 2-2: Synthesis of 9-phenyl-9H-carbazole-3-boronic acid]

[0443] The following (D-2-2) shows a synthesis scheme of 9-phenyl-9H-carbazole-3-boronic acid in Step 2-2.

[0444]

[0445] In a 500-mL conical flask, 29 g (90 mmol) of 3-bromo-9-phenyl-9H-carbazole and 200 mL of tetrahydrofuran (THF) were stirred to be dissolved at -78°C. Then, 110 mL (69 mmol) of n-butyllithium (1.57 mol / L hexane solution) was added dropwise to the solution, and the solution was stirred at the same temperature for 2 hours. Separately, 13 mL (140 mmol) of trimethyl borate was added to the solution, and the solution was stirred at room temperature for 24 hours.

[0446] After the reaction was completed, 200 mL of hydrochloric acid (1.0 mol / L) was added to the reaction mixture, and then the mixture was stirred at room temperature for 1 hour. The mixture was washed with an aqueous sodium hydroxide solution and water in this order, and magnesium sulfate was added to remove moisture. The suspension was filtered, and the obtained filtrate was concentrated, and chloroform and hexane were added thereto. The mixture was treated with ultrasonic waves. Then, recrystallization was performed. Thus, 21 g of the target white powder 9-phenyl-9H-carbazole-3-boronic acid was obtained at a yield of 80%.

[0447] [Step 3: Synthesis of 4-(9-phenyl-9H-carbazole-3-yl)diphenylamine (abbreviation: PCBA)]

[0448] The following (D-3) shows a synthesis scheme of 4-(9-phenyl-9H-carbazole-3-yl)diphenylamine (abbreviation: PCBA) in Step 3.

[0449]

[0450] In a 500-mL three-necked flask, 6.5 g (26 mmol) of 4-bromo-N,N-diphenylaniline, 7.5 g (26 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, and 400 mg (1.3 mmol) of tris(o-tolyl)phosphine were added, and the atmosphere in the flask was replaced with nitrogen. Then, 100 mL of toluene, 50 mL of ethanol, and 14 mL of a potassium carbonate solution (0.2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, 67 mg (30 mmol) of palladium (II) acetate was added thereto.

[0451] The mixture was refluxed at 100°C for 10 hours. After refluxing, the aqueous layer of the mixture was extracted with toluene. Then, the extract and the organic layer were combined, and then washed with a saturated saline solution. After removing the moisture from the organic layer with magnesium sulfate, the mixture was naturally filtered, and the obtained filtrate was concentrated to obtain an oily light brown substance. The oily substance was purified by silica gel column chromatography (developing solvent, hexane:toluene = 4:6). After purification, the obtained white solid was recrystallized with dichloromethane / hexane to obtain 4.9 g of the target white solid at a yield of 45%.

[0452] [Step 4: Synthesis of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)diphenylamine (abbreviation: PCBA1BP)]

[0453] The following (D-4) shows a synthesis scheme of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)diphenylamine (abbreviation: PCBA1BP) in Step 4.

[0454]

[0455] In a 100-mL three-necked flask, 2.0 g (4.9 mmol) of 4-(9-phenyl-9H-carbazol-3-yl)diphenylamine, 1.1 g (4.9 mmol) of 4-bromobiphenyl, and 2.0 g (20 mmol) of sodium tert-butoxide were added, and the atmosphere in the flask was replaced with nitrogen. Then, 50 mL of toluene and 0.30 mL of tri(tert-butyl)phosphine (10% (w / v) hexane solution) were added to the mixture.

[0456] The mixture was degassed under low pressure with stirring. After degassing, 0.10 g of palladium (0) bis(dibenzylideneacetone) was added thereto. Subsequently, the mixture was stirred at 80°C for 5 hours to allow the reaction. After the reaction, toluene was added to the reaction mixture, and the suspension was sequentially filtered through celite, alumina, and Florisil by suction filtration to obtain a filtrate. The obtained filtrate was sequentially washed with a saturated sodium carbonate solution and a saturated saline solution. Magnesium sulfate was added to the organic layer, and the organic layer was dried. After drying, the mixture was suction-filtered to remove the magnesium sulfate; thus, a filtrate was obtained.

[0457] ​​​​​​​The obtained filtrate was concentrated and purified by silica gel column chromatography. Elution was performed sequentially with a toluene:hexane mixture of 1:9 as the developing solvent and a toluene:hexane mixture of 3:7 as the second developing solvent. The resulting fraction was concentrated, and the solid was recrystallized from the solid by a mixture of chloroform and hexane to give 2.3 g of a white powder, in 84% yield.

[0458] The obtained 1.2 g white solid was purified by train sublimation. The purification process was carried out under reduced pressure of 7.0 Pa, with an argon flow rate of 3 mL / min, at 280 °C for 20 hours. This yielded 1.1 g of white solid, with a yield of 89%.

[0459] By nuclear magnetic resonance (NMR) 1 The compound obtained in step 4 above was measured by 1H NMR. The measurement results are described below. FIG. 10A and 10B Display in 1 1H NMR spectrum. The measurement results show that the carbazole derivative of the present invention, 4-phenyl-4′-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), represented by the above structural formula (5), was obtained.

[0460] 1 H NMR (DMSO-d, 300MHz): δ (ppm) = 7.05-7.20 (m, 7H), 7.28-7.78 (m, 21H), 8.34 (d, J = 7.8Hz, 1H), 8.57 (s, 1H).

[0461] in addition, FIG. 11A The absorption spectrum of a toluene solution containing PCBA1BP (abbreviation) is shown. Additionally, FIG. 11B The absorption spectrum of the PCBA1BP (abbreviation) thin film is shown. Measurements were taken using a UV-Vis spectrophotometer (V-550, manufactured by JASCO Corporation). The spectrum of the solution was measured in a quartz cell. The thin film sample was prepared by evaporating PCBA1BP (abbreviation) vapor onto a quartz substrate. FIG. 11A The solution absorption spectrum is displayed by subtracting the quartz cell absorption from the absorption of the sample being tested. FIG. 11B The thin film absorption spectrum is displayed by subtracting the quartz matrix absorption from the absorption of the sample being tested.

[0462] exist FIG. 11A and 11B In the diagram, the horizontal axis represents wavelength (nm), and the vertical axis represents absorption intensity (any unit). In the case of toluene solution, an absorption peak is observed at approximately 335 nm; in the case of a thin film, an absorption peak is observed at approximately 341 nm. Additionally,FIG. 11A The emission spectrum of a toluene solution of PCBA1BP (abbreviation) is also shown (excitation wavelength: 346 nm). In addition, FIG. 11B The film emission spectrum of PCBA1BP (abbreviation) is also shown (excitation wavelength: 386 nm). In FIG. 11A and 11B In each of Figs. 16, 17, 18, and 19, the horizontal axis represents wavelength (nm), and the vertical axis represents light emission intensity (arbitrary unit). In the case of the toluene solution, the maximum emission wavelength was 391 nm (excitation wavelength: 346 nm); in the case of the film, the maximum emission wavelength was 416 nm (excitation wavelength: 386 nm).

[0463] The oxidation-reduction reaction characteristics of PCBA1BP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Measurement was performed with an electrochemical analyzer (ALS type 600A or 600C, manufactured by BAS Inc.).

[0464] As the solution for CV measurement, tetra-n-butylammonium perchlorate (n-Bu4NClO4, product of Tokyo Chemical Industry Co., Ltd., catalog number T0836) was dissolved in dehydrated dimethylformamide (DMF) (produced by Aldrich, 99.8%, catalog number: 22705-6) as a solvent to make the concentration 100 mmol / L. In addition, the object to be measured was also dissolved in the solvent to make the concentration 2 mmol / L. A platinum electrode (PTE platinum electrode, manufactured by BAS Inc.) was used as the working electrode, another platinum electrode (Pt counter electrode for VC-3 (5 cm), produced by BAS Inc.) was used as the auxiliary electrode, and an Ag / Ag + electrode (RE7 reference electrode for non-aqueous solvent, manufactured by BAS Inc.) was used as the reference electrode. Note that measurement was performed at room temperature (20°C to 25°C). In addition, the scan rate for CV measurement was 0.1 V / sec.

[0465] (Calculation of potential energy of reference electrode with respect to vacuum level)

[0466] First, the potential energy (eV) of the reference electrode (Ag / Ag + electrode) with respect to the vacuum level for Embodiment 1 was calculated. That is, the potential energy of the Ag / Ag +The Fermi level of the electrode. The redox potential of ferrocene in methanol is known to be +0.610 V relative to the standard hydrogen electrode [relative to SHE] (see: Christian R. Goldsmith et al., J. Am. Chem. Soc., Vol. 124, No. 1, pp. 83-96, 2002). On the other hand, the redox potential of ferrocene in methanol, measured by the reference electrode used in Embodiment 1, was found to be +0.11 V [relative to Ag / Ag]. + Therefore, it was found that the potential energy of the reference electrode used in embodiment 1 was 0.50 eV less than that of the standard hydrogen electrode.

[0467] Here, it is also known that the potential energy of the standard hydrogen electrode relative to the vacuum level is -4.44 eV (see: Toshihiro Ohnishi and Tamami Koyama, Macromolecular EL material, Kyoritsu Shuppan, pp. 64-67). As described above, the potential energy of the reference electrode relative to the vacuum level used in Embodiment 1 is calculated to be -4.44 -0.50 = -4.94 [eV].

[0468] FIG. 41 The CV measurement results for the oxidation reaction characteristics are shown. Note that the oxidation reaction characteristics were measured by sequentially scanning the working electrode potential relative to the reference electrode in the ranges of (1) 0.07V-1.00V and (2) 1.00V-0.07V.

[0469] First, describe in detail how the HOMO level of PCBA1BP (abbreviation) is calculated using CV measurement. For example... FIG. 41 As shown, the oxidation peak potential E pa It is 0.536V. Additionally, the reduction peak potential E... pc It is 0.446V. Therefore, the half-wave potential (E) can be calculated. pc With E pa The intermediate potential between them is 0.49V. This shows that 0.49V of electrical energy [relative to Ag / Ag] can be transmitted. + Oxidation of PCBA1BP (abbreviation) corresponds to the HOMO level.

[0470] Here, as described above, the potential energy of the reference electrode relative to the vacuum level used in Embodiment 1 is -4.94 [eV]. Therefore, the HOMO level of PCBA1BP (abbreviation) is found to be -4.94 - 0.49 = -5.43 [eV]. Furthermore, even after 100 cycles, the oxidation peak still has a similar value. Therefore, the redox repetition between the oxidized and neutral states is found to be a favorable characteristic.

[0471] [Embodiment 2]

[0472] In Embodiment 2, a method for synthesizing the carbazole derivative of the present application represented by Structural Formula (6), 4,4'-diphenyl-4"-(9-phenyl-9-H-carbazol-3-yl)triphenylamine (abbreviation: PCBBBi1BP), will be specifically described.

[0473]

[0474] [Step 1-1: Synthesis of 4-phenyl-diphenylamine]

[0475] The following (E-1-1) shows a synthesis scheme of 4-phenyl-diphenylamine in Step 1-1.

[0476]

[0477] In a three-necked flask, 5.2 g (2.5 mmol) of tri-tert-butylphosphine (10% (w / v) hexane solution) was added to a suspension of 20.0 g (85.8 mmol) of 4-bromobiphenyl, 16.0 g (172 mmol) of aniline, 0.19 g (0.86 mmol) of palladium (II) acetate, and 23.7 g (172 mmol) of potassium carbonate in anhydrous xylene (150 mL), and the mixture was refluxed under a nitrogen atmosphere at 120°C for 10 hours. After completion of the reaction, the reaction mixture was washed with water, and the organic layer and the aqueous layer were separated, and the aqueous layer was extracted with toluene.

[0478] The toluene layer obtained above was combined with the organic layer above, and then washed with a saturated saline solution. Then, magnesium sulfate was added thereto, and the organic layer was freed from water. The mixture was suction-filtered, and the obtained filtrate was concentrated. The obtained residue was purified by silica gel column chromatography (developing solvent: toluene). The obtained solution was concentrated, thereby obtaining 13.5 g of 4-phenyl-diphenylamine as a white solid at a yield of 64%.

[0479] [Step 1-2: Synthesis of 4,4'-diphenyltriphenylamine]

[0480] The following (E-1-2) shows a synthesis scheme of 4,4'-diphenyltriphenylamine in Step 1-2

[0481]

[0482] In a 100-mL three-necked flask, 3.7 g (15 mmol) of 4-phenyl-diphenylamine, 3.5 g (15 mmol) of 4-bromobiphenyl, 2.5 g (25 mmol) of sodium tert-butoxide, and 10 mg (0.02 mmol) of bis(dibenzylideneacetone) palladium(0) were added, and the atmosphere in the flask was replaced with nitrogen. Then, 40 mL of anhydrous xylene was added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, 0.2 mL (60 mmol) of tri(tert-butyl)phosphine (10% (wt) hexane solution) was added thereto.

[0483] Then, the mixture was stirred at 120°C for 5 hours to allow the reaction. After the reaction, toluene was added to the reaction mixture, and the mixture was filtered through diatomaceous earth, alumina, and Florisil in this order, and the suspension was suction-filtered to obtain a filtrate. The obtained filtrate was washed with saturated sodium carbonate solution and saturated brine solution in this order. Magnesium sulfate was added to the obtained organic layer to remove moisture. The mixture was filtered through diatomaceous earth, alumina, and Florisil in this order, and the mixture was suction-filtered to obtain a filtrate. Acetone and methanol were added to the obtained residue, and the residue was treated with ultrasonic waves, and then recrystallized to obtain 5.4 g of a white powdery solid, with a yield of 92%.

[0484] [Step 1': Synthesis of 4,4'-diphenyltriphenylamine]

[0485] In addition to Step 1-1 and Step 1-2 described above, 4,4'-diphenyltriphenylamine can also be synthesized using the synthesis method shown in Step 1'. Note that the following (E-1') shows a flow of synthesis of 4,4'-diphenyltriphenylamine in Step 1'.

[0486]

[0487] In a 200-mL three-necked flask, 1.9 g (20 mmol) of aniline, 9.3 g (40 mmol) of 4-bromo biphenyl, 4.5 g (45 mmol) of sodium tert-butoxide, 0.4 g (2.0 mmol) of palladium (II) acetate, and 1.1 g (2.0 mmol) of 1,1-bis(diphenylphosphino) ferrocene (abbreviation: DPPF) were added, and the atmosphere in the flask was replaced with nitrogen. Then, 70 mL of anhydrous xylene was added to the mixture. The mixture was degassed under low pressure with stirring, and the mixture was stirred at 110°C for 3 hours to allow the reaction. After the reaction, toluene was added to the reaction mixture, and the suspension was sequentially passed through celite, alumina, and Florisil by suction filtration to obtain a filtrate. The obtained filtrate was sequentially washed with a saturated sodium carbonate solution and a saturated brine solution. Magnesium sulfate was added to the obtained organic layer to remove moisture. The mixture was sequentially passed through celite, alumina, and Florisil by suction filtration, and the obtained filtrate was concentrated. Acetone and hexane were added to the obtained residue, and the residue was recrystallized with ultrasonic treatment to obtain 5.4 g of a white powdery solid at a yield of 67%.

[0488] [Step 2: Synthesis of 4-bromo-4',4"-diphenyltriphenylamine]

[0489] 4-bromo-4',4"-diphenyltriphenylamine was synthesized from 4,4'-diphenyltriphenylamine synthesized by the synthesis method shown in Step 1-1 and Step 1-2 or Step 1' above. Note that the following (E-2) shows a synthesis flow of 4-bromo-4',4"-diphenyltriphenylamine shown in Step 2.

[0490]

[0491] In a conical flask, 4.0 g (10 mmol) of 4,4'-diphenyltriphenylamine was dissolved in a 50 mL toluene and 50 mL ethyl acetate mixed solvent, and N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 120 hours. After the completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the obtained filtrate was concentrated and recrystallized. Thus, 4.5 g of the target white powder was obtained at a yield of 95%.

[0492] [Step 3: Synthesis of 4,4'-diphenyl-4"-(9-phenyl-9-H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP)]

[0493] The following (E-3) shows a synthesis flow of 4,4'-diphenyl-4"-(9-phenyl-9-H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP) in Step 3.

[0494] The following (E-3) shows a synthesis flow of 4,4'-diphenyl-4"-(9-phenyl-9-H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP) in Step 3.

[0495] In a 100-mL three-necked flask, 1.5 g (3.1 mmol) of 4-bromo-4',4"-diphenyltriphenylamine, 0.9 g (3.1 mmol) of 9-phenyl-9H-carbazole-3-boric acid, 50 mg (0.023 mmol) of palladium(II) acetate, and 0.050 g (0.17 mmol) of tris(o-tolyl)phosphine were added, and the atmosphere in the flask was purged with nitrogen. Note that since the synthesis method of 9-phenyl-9H-carbazole-3-boric acid is similar to that described in Example 1, and its description is cited therein, the method description is omitted here. 30 mL of dimethyl ethylene glycol (DME) and 15 mL of potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassed, the mixture was stirred at 90 °C for 5 hours to allow the reaction to proceed.

[0496] After the reaction, ethyl acetate was added to the reaction mixture, and the suspension was washed with saturated sodium bicarbonate solution and saturated salt solution. Magnesium sulfate was added to the organic layer, and the organic layer was dried. After drying, the mixture was filtered to remove the magnesium sulfate, thus obtaining a filtrate. The obtained filtrate was concentrated, and toluene was added to the obtained solid to dissolve the mixture. Then, the solution was filtered sequentially through diatomaceous earth, alumina, and Florisil to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. Elution was performed sequentially with a toluene:hexane = 1:9 mixed solvent as the developing solvent and a toluene:hexane = 3:7 mixed solvent as another developing solvent, followed by silica gel column chromatography.

[0497] The obtained fraction was concentrated, and the resulting solid was recrystallized from a mixed solvent of dichloromethane and hexane to give 1.3 g of the target white solid, with a yield of 66%. 1.1 g of the obtained white solid was purified by sublimation. Sublimation purification was carried out at 305 °C and 7.0 Pa under reduced pressure for 15 hours at an argon flow rate of 4 mL / min. This yielded 840 mg of white solid, with a yield of 76%.

[0498] By nuclear magnetic resonance (NMR) 1 The compound obtained in step 4 above was measured by 1H NMR. The measurement results are described below. FIG. 12A and 12B Display in 1 1H NMR spectrum. The measurement results show that the carbazole derivative of the present invention, 4,4'-diphenyl-4"-(9-phenyl-9-H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), represented by the above structural formula (6), was obtained.

[0499] 1H NMR (CDC13, 300 MHz): δ (ppm) = 7.25-7.69 (m, 32H), 8.19 (d, J = 7.3 Hz, IH), 8.35 (s, IH).

[0500] In addition, FIG. 13A In addition, FIG. 13B In addition, FIG. 13A In addition, FIG. 13B In addition, FIG. 13A In addition, 13B In addition, FIG. 13A In addition, FIG. 13B In addition, FIG. 13A In addition, 13B In addition,

[0501] The oxidation-reduction reaction characteristics of PCBBi1BP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the method description was omitted.

[0502] FIG. 42 The CV measurement results for the oxidation reaction characteristics are shown. As shown in FIG. 42 the oxidation peak potential E pa was 0.521 V, and the reduction peak potential E pc was +0.431 V. Thus, the half-wave potential (E pc and E paThe oxidation potential (the potential between the intermediate potential and the anodic potential) was +0.48 V. According to a calculation similar to that of Embodiment 1, the HOMO level of PCBBi1BP (abbreviation) was found to be -5.42 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0503] The HOMO level of PCBBi1BP (abbreviation) was -5.34 eV, as a result of measurement of a thin film with a spectroscopic ellipsometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure. The Tauc plot of the absorption spectrum of the thin film showed that the absorption edge was 3.15 eV. Thus, the energy gap in the solid state was estimated to be 3.15 eV, indicating that the LUMO level of PCBBi1BP (abbreviation) was -2.19 eV.

[0504] In addition, the glass transition temperature of PCBBi1BP (abbreviation) was detected with a differential scanning calorimeter (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement result, the glass transition temperature was found to be 123°C. In this way, PCBBi1BP (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; thus, PCBBi1BP (abbreviation) was found to be a substance that is difficult to crystallize.

[0505] [Embodiment 3]

[0506] In Embodiment 3, a method for synthesizing a carbazole derivative represented by Structural Formula (7), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-fluorene-2-amine (abbreviation: PCBAF), of the present application will be specifically described.

[0507]

[0508] [Step 1: Synthesis of 2-bromo-9,9-dimethylfluorene]

[0509] The following (F-1) shows a synthesis scheme of 2-bromo-9,9-dimethylfluorene in Step 1.

[0510]

[0511] In a 500-mL Erlenmeyer flask, 12.5 g (51 mmol) of 2-bromofluorene, 8.5 g (51 mmol) of potassium iodide, 14.3 g (0.50 mol) of potassium hydroxide, and 250 mL of dimethyl sulfoxide were stirred for 30 minutes. Then, 10 mL of methyl iodide was gradually added to the mixture. The mixture was stirred at room temperature for 48 hours. After the reaction, 400 mL of chloroform was added to the reaction solution, and the mixture was stirred. The solution was washed with IN hydrochloric acid, a saturated sodium carbonate solution, and a saturated brine solution in this order. Magnesium sulfate was added to the resulting organic layer to remove moisture.

[0512] The mixture was suction-filtered and concentrated. Then, the residue was purified by silica gel column chromatography. The silica gel column chromatography was performed by elution with hexane as a developing agent, and a mixed solvent of ethyl acetate:hexane = 1:5 as another developing agent in this order. The corresponding fraction was concentrated and dried to obtain 12 g of a brown oily substance at a yield of 97%.

[0513] [Step 2: Synthesis of 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-fluoren-2-amine (abbreviation: PCBAF)]

[0514] The following (F-2) shows a synthesis scheme of 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-fluoren-2-amine (abbreviation: PCBAF) in Step 2.

[0515]

[0516] In a 100-mL three-necked flask, 2.0 g (4.9 mmol) of 4-(9-phenyl-9H-carbazol-3-yl)diphenylamine (abbreviation: PCBA), 1.3 g (4.9 mmol) of 2-bromo-9,9-dimethylfluorene, and 2.0 g (20 mmol) of sodium tert-butoxide were placed, and the atmosphere in the flask was replaced with nitrogen. Note that since the synthesis method of PCBA (abbreviation) is similar to the method described in Embodiment 2, the description thereof is referred to; thus, the description is omitted here. Then, 50 mL of toluene and 0.30 mL of tri(tert-butyl)phosphine (10 wt% hexane solution) were added to the mixture. The mixture was degassed with stirring under low pressure. After the degassing, 0.10 g of bis(dibenzylideneacetone) palladium(0) was added thereto. Then, the mixture was stirred at 80°C for 5 hours to allow the reaction. After the reaction, toluene was added to the reaction mixture, and the suspension was passed through celite, alumina, and Florisil in this order by suction filtration to obtain a filtrate.

[0517] The obtained filtrate was concentrated and purified by silica gel column chromatography. The silica gel column chromatography was performed by elution with toluene:hexane = 1 :9 mixed solvent as a developing agent and toluene:hexane = 3 :7 mixed solvent as another developing agent, successively. The obtained fraction was concentrated, and the obtained solid was recrystallized with a chloroform and hexane mixed solvent to obtain 1.3 g of the target compound at a yield of 44%.

[0518] The obtained 1.3 g of light yellow solid was purified by sublimation. The sublimation purification was performed at 270°C under a reduced pressure of 7.0 Pa at an argon gas flow rate of 3 mL / min for 20 hours. Thus, 1.0 g of light yellow solid was obtained at a yield of 77%.

[0519] The compound obtained by the above Step 2 was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 14A and 14B The 1H NMR spectrum is shown in 1 It was found from the measurement results that the carbazole derivative of the present application represented by the above structural formula (7), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-fluorene-2-amine (abbreviation: PCBAF), was obtained.

[0520] 1 1H NMR (DMSO-d6, 300 MHz): δ (ppm) = 1.39 (s, 6H) 6.98-7.82 (m, 26H), 8.35 (d, J = 6.8 Hz, IH), 8.57 (s, IH).

[0521] In addition, FIG. 15A The absorption spectrum of a toluene solution of PCBAF (abbreviation) is shown. In addition, FIG. 15B The thin film absorption spectrum of PCBAF (abbreviation) is shown. The measurement was performed with a UV-Vis spectrophotometer (V-550, manufactured by JASCO Corporation). The spectrum of the solution was measured in a quartz cell. The thin film sample was prepared by vapor deposition of PCBAF (abbreviation) on a quartz substrate. FIG. 15A The absorption spectrum of the solution is shown by subtracting the absorption of the quartz cell from the absorption of the measured sample; FIG. 15B The thin film absorption spectrum is shown by subtracting the absorption of the quartz substrate from the absorption of the measured sample, in FIG. 15A and 15B The horizontal axis represents wavelength (nm) and the vertical axis represents absorption intensity (arbitrary unit). In the case of the toluene solution, an absorption peak was observed at about 339 nm; in the case of the thin film, an absorption peak was observed at about 345 nm. In addition, FIG. 15AThe emission spectrum (excitation wavelength: 347 nm) of a toluene solution of PCBAF (abbreviation) is shown. In addition, FIG. 15B The thin film emission spectrum (excitation wavelength: 370 nm) of PCBAF (abbreviation) is shown. In the case of a toluene solution, the maximum emission wavelength is 394 nm (excitation wavelength: 347 nm); in the case of a thin film, the maximum emission wavelength is 404 nm (excitation wavelength: 370 nm). FIG. 15A and 15B In each of Figs. 11, 12, and 13, the horizontal axis represents wavelength (nm), and the vertical axis represents light emission intensity (arbitrary units). In the case of a toluene solution, the maximum emission wavelength is 394 nm (excitation wavelength: 347 nm); in the case of a thin film, the maximum emission wavelength is 404 nm (excitation wavelength: 370 nm).

[0522] The oxidation-reduction reaction characteristics of PCBAF (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method is similar to that of Embodiment 1, the method description is omitted.

[0523] FIG. 43 The CV measurement results for the oxidation reaction characteristics are shown. As shown in FIG. 43 , the oxidation peak potential E pa readable was 0.481 V, and the reduction peak potential E pc readable was +0.393 V. Thus, the intermediate potential between E pc and E pa , the half-wave potential, was found to be +0.44 V. According to a calculation similar to that of Embodiment 1, the HOMO level of PCBAF (abbreviation) was found to be -5.38 [eV]. In addition, even after 100 cycles, the oxidation peak had a similar value. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0524] [Embodiment 4]

[0525] In Embodiment 4, the synthesis method of the carbazole derivative of the present application represented by structural formula (8), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF), will be described in detail.

[0526]

[0527] [Step 1-1: Synthesis of 9-(biphenyl-2-yl)-2-bromofluoren-9-ol]

[0528] The following (G-1-1) shows the synthesis scheme of 9-(biphenyl-2-yl)-2-bromofluoren-9-ol in Step 1-1.

[0529]

[0530] In a 100-mL three-necked flask connected to a dropping funnel and a Dimroth condenser, 1.26 g (0.052 mol) of magnesium was added, and the flask was evacuated. The magnesium was activated by heating and stirring for 30 minutes. After cooling to room temperature, the flask was placed under a stream of nitrogen. Then, 5 mL of diethyl ether and a few drops of dibromoethane were added thereto, and 11.65 g (0.050 mol) of 2-bromobiphenyl dissolved in 15 mL of diethyl ether was slowly dropped from the dropping funnel into the mixture. After the dropping was completed, the mixture was refluxed for 3 hours to prepare a Grignard reagent.

[0531] In a 200-mL three-necked flask connected to a dropping funnel and a Dimroth condenser, 11.7 g (0.045 mol) of 2-bromo-9-fluorenone and 40 mL of diethyl ether were added. The Grignard reagent synthesized was slowly dropped from the dropping funnel into the reaction solution. After the dropping was completed, the mixture was refluxed for 2 hours and then stirred at room temperature overnight. After the reaction was completed, the solution was washed twice with a saturated ammonium chloride solution, and separated into an aqueous layer and an organic layer. The obtained aqueous layer was extracted twice with ethyl acetate, and the ethyl acetate solution and the obtained organic layer were washed with a saturated brine solution. After the water was removed with magnesium sulfate, the solution was suction-filtered, and concentrated to obtain 18.76 g of 9-(biphenyl-2-yl)-2-bromo-9-fluorenol as a solid, with a yield of 90%.

[0532] [Step 1-2: Synthesis of 2-bromo-spiro-9,9'-bifluorene]

[0533] The following (G-1-2) shows a synthesis scheme of 2-bromo-spiro-9,9'-bifluorene in Step 1-2

[0534]

[0535] In a 200-mL three-necked flask, 18.76 g (0.045 mol) of 9-(biphenyl-2-yl)-2-bromo-9-fluorenol synthesized was added, and 100 mL of glacial acetic acid was added thereto, and a few drops of concentrated hydrochloric acid were added, and the mixture was refluxed for 2 hours. After the reaction was completed, the precipitate was collected by suction filtration, and the precipitate was filtered and washed with a saturated sodium bicarbonate solution and water. The obtained brown solid was recrystallized with ethanol to obtain 10.24 g of a light brown powder as a solid, with a yield of 57%.

[0536] [Step 2: Synthesis of N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF)]

[0537] The following (G-2) shows a synthesis scheme of N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF) in Step 2

[0538]

[0539] In a 100-mL three-necked flask, 2.0 g (4.9 mmol) of 4-(9-phenyl-9H-carbazol-3-yl)diphenylamine (abbreviation: PCBA), 1.9 g (4.9 mmol) of 2-bromo-spiro-9,9'-bifluorene, and 2.0 g (20 mmol) of sodium tert-butoxide were placed, and the atmosphere in the flask was replaced with nitrogen. Then, 50 mL of toluene and 0.30 mL of tri(tert-butyl)phosphine (10% by weight hexane solution) were added to the mixture. The mixture was degassed with stirring at a low pressure. After degassing, 0.10 g of bis(dibenzylideneacetone) palladium(0) was added thereto.

[0540] Then, the mixture was stirred at 80°C for 5 hours to allow the reaction. After the reaction, toluene was added to the reaction mixture, and the suspension was sequentially passed through celite, alumina, and Florisil by suction filtration to obtain a filtrate. The obtained filtrate was washed with a saturated sodium carbonate solution and a saturated saline solution in this order. After magnesium sulfate was added to the organic layer to remove water, the mixture was suction-filtered to remove the magnesium sulfate, and a filtrate was obtained. The obtained filtrate was concentrated, and the obtained solid was recrystallized from a chloroform-hexane mixed solvent to obtain 3.4 g of a white powdery solid at a yield of 94%. The obtained 2.3 g of white solid was purified by sublimation. Sublimation purification was performed at 310°C for 20 hours under a reduced pressure of 7.0 Pa at an argon flow rate of 3 mL / min. Thus, 1.7 g of a white solid was obtained at a yield of 74%.

[0541] The compound obtained in Step 2 above was measured by nuclear magnetic resonance (1H NMR). 1 The measurement results are described below, FIG. 16A and 16B show 1 the 1H NMR spectrum. It was found from the measurement results that the carbazole derivative of the present application represented by the above structural formula (8), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF), was obtained.

[0542] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 6.61-6.70 (m, 2H), 6.83 (d, J = 8.3 Hz, 2H), 6.88-7.79 (m, 30H), 8.16 (d, J = 8.3 Hz, 1H), 8.26 (s, 1H).

[0543] In addition, FIG. 17A shows the absorption spectrum of a toluene solution of PCBASF (abbreviation). In addition, FIG. 17BAbsorption spectra of a thin film of PCBASF (abbreviation) are shown. The measurement was made with a UV-visible spectrophotometer (V-550, manufactured by JASCO Corporation). The spectrum of a solution was measured in a quartz cell. The thin film sample was prepared by evaporating a vapor of PCBASF (abbreviation) on a quartz substrate. FIG. 17A Absorption spectra of a solution are shown, obtained by subtracting the absorption of the quartz cell from the absorption of the sample being measured; FIG. 17B Absorption spectra of a thin film are shown, obtained by subtracting the absorption of the quartz substrate from the absorption of the sample being measured. In FIG. 17A and 17B , the horizontal axis represents wavelength (nm), and the vertical axis represents absorption intensity (arbitrary units). In the case of a toluene solution, an absorption peak was observed at about 338 nm; in the case of a thin film, an absorption peak was observed at about 345 nm. In addition, FIG. 17A Emission spectra of a toluene solution of PCBASF (abbreviation) are also shown (excitation wavelength: 352 nm). In addition, FIG. 17B Emission spectra of a thin film of PCBASF (abbreviation) are also shown (excitation wavelength: 371 nm). In FIG. 17A and 17B , the horizontal axis represents wavelength (nm), and the vertical axis represents light emission intensity (arbitrary units). In the case of a toluene solution, the maximum emission wavelength was 396 nm (excitation wavelength: 352 nm), and in the case of a thin film, the maximum emission wavelength was 427 nm (excitation wavelength: 371 nm).

[0544] The oxidation-reduction reaction characteristics of PCBASF (abbreviation) were examined by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted.

[0545] FIG. 44 CV measurement results for the oxidation reaction characteristics are shown. As shown in FIG. 44 , the oxidation peak potential E pa was 0.52 V, and the reduction peak potential E pc was +0.428 V. Thus, the intermediate potential between E pc and E pa was calculated to be +0.47 V. According to a calculation similar to that of Embodiment 1, the HOMO level of PCBASF (abbreviation) was found to be = -5.41 [eV]. In addition, even after 100 cycles, the oxidation peak had a similar value. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0546] [Embodiment 5]

[0547] In Embodiment 5, a method for producing light emitting elements 2, 3, 4, and 5 formed using the carbazole derivatives of the present application synthesized in Embodiments 1 to 4, and the results of measuring the characteristics of the elements will be described. The light emitting element 2 was formed using 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP); the light emitting element 3 was formed using 4,4'-diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), the light emitting element 4 was formed using 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBAF); and the light emitting element 5 was formed using N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spiro-9H-fluorene-2-amine (abbreviation: PCBASF).

[0548] Note that, FIG. 18 Each of the element structures of the light emitting elements in Embodiment 5 is shown in which the hole-transport layer 1512 is formed using the above carbazole derivatives of the present application. In addition, the light emitting element 1, which is a comparative light emitting element, is formed using 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) for the hole-transport layer 1512. In order to make the conditions for comparison of the light emitting element 1 with each of the light emitting elements 2 to 5 the same, the light emitting element 1 is formed on the same substrate as the light emitting elements 2 to 5, and the light emitting element 1 is compared with the light emitting elements 2 to 5. The structural formulas of the organic compounds used in Embodiment 5 are shown below.

[0549]

[0550] First, an indium tin oxide containing silicon oxide was deposited by a sputtering method on a substrate 1501 serving as a glass substrate to form a first electrode 1502. The thickness of the first electrode 1502 was set to 110 nm, and the area was set to 2 mm x 2 mm.

[0551] Then, an EL layer 1503 was formed in which a plurality of layers were stacked over the first electrode 1502. In Embodiment 5, the EL layer 1503 has a structure in which a first layer 1511 serving as a hole-injection layer, a second layer 1512 serving as a hole-transport layer, a third layer 1513 serving as a light emitting layer, a fourth layer 1514 serving as an electron-transport layer, and a fifth layer 1515 serving as an electron-injection layer were stacked in this order.

[0552] The substrate having the first electrode 1502 was fixed to a substrate holder, was provided in a vacuum evaporation apparatus in such a manner that the surface of the first electrode 1502 faced downward, and then the pressure was reduced to about 10 -4Pa. Then, 4,4'-bis[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) and molybdenum (VI) oxide are co-evaporated on the first electrode 1502, whereby a first layer 1511 which is a hole-injection layer is formed. The evaporation rate is controlled so that the thickness of the first layer as the hole-injection layer can be 50 nm and the weight ratio of NPB to molybdenum (VI) oxide can be 4: 1 (= NPB: molybdenum oxide). Note that the co-evaporation method is an evaporation method in which evaporation is performed at the same time with a plurality of evaporation sources in one treatment chamber.

[0553] Then, a hole-transport material is deposited on the first layer 1511 by an evaporation method with resistive heating so that the thickness is 10 nm, whereby a second layer 1512 which is a hole-transport layer is formed. Note that 4,4'-bis[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) is used in the case of forming the light-emitting element 1, 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP) is used in the case of forming the light-emitting element 2, 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP) is used in the case of forming the light-emitting element 3, 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-fluorene-2-amine (abbreviation: PCBAF) is used in the case of forming the light-emitting element 4, and N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF) is used in the case of forming the light-emitting element 5.

[0554] Then, a third layer 1513 which is a light-emitting layer is formed on the second layer 1512 by an evaporation method with resistive heating. The third layer 1513 is formed by co-evaporating 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA) and 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA) to a thickness of 30 nm. Here, the evaporation rate is controlled so that the weight ratio of CzPA to PCBAPA can be 1:0.10 (= CzPA:PCBAPA).

[0555] In addition, tris(8-hydroxyquinolinate)aluminum (III) (abbreviation: AIq) is deposited on the third layer 1513 by an evaporation method with resistive heating to a thickness of 10 nm. Then, a fourth layer 1514 which is an electron-transport layer is formed by depositing bathophenanthroline (abbreviation: BPhen) on the third layer 1513 to a thickness of 20 nm.

[0556] Then, a fifth layer 1515 as an electron-injection layer was formed by depositing lithium fluoride (LiF) on the fourth layer 1514 to a thickness of 1 nm.

[0557] Finally, a second electrode 1504 was formed by depositing aluminum to a thickness of 200 nm by an evaporation method using resistance heating, and a light-emitting element 1-5 was formed.

[0558] The light-emitting element 1-5 obtained by the above method was put in a glove box having a nitrogen atmosphere so that the light-emitting element was sealed but not exposed to the atmosphere. Then, the operation characteristics of the light-emitting element were measured. Note that the measurement was performed at room temperature (at 25 °C under normal pressure).

[0559] FIG. 19 The relationship between the current density and the luminance characteristics of the light-emitting elements 1 and 2 was shown. FIG. 20 The relationship between the voltage and the luminance characteristics of the light-emitting elements 1 and 2 was shown. FIG. 21 The relationship between the luminance and the current efficiency characteristics of the light-emitting elements 1 and 2 was shown. FIG. 22 The relationship between the voltage and the current characteristics of the light-emitting elements 1 and 2 was shown.

[0560] When the excitation voltage of the light-emitting element 2 was 3.4 V, the luminance and the current value were 1277 cd / m 2 and 0.79 mA, respectively. It was found that the light-emitting element 2 using PCBA1BP (abbreviation) for the second layer 1512 showed higher luminance even when compared with the light-emitting element 1 using NPB for the second layer 1512. In addition, it was also found that the current efficiency was high in terms of current density or luminance.

[0561] In addition, in the light-emitting element 2, the emission wavelength from the hole-transport material was not observed in the emission spectrum shown in FIG. 6B. FIG. 23 Thus, it was found that an advantageous carrier balance was achieved in the structure of the light-emitting element 2 using the PCBA1BP (abbreviation) of the present application.

[0562] FIG. 24 The results of an uninterrupted lighting test in which the light-emitting element 2 was continuously lit by constant current driving, with the initial luminance set to 1000 cd / m 2 (the vertical axis indicates the relative luminance, assuming that 1000 cd / m 2 is 100 %). FIG. 24 The results shown in FIG. 6C show that the light-emitting element 2 showed 92 % of the initial luminance even after 160 hours, and it was found that the lifetime was longer than that of the light-emitting element 1. Thus, a light-emitting element with a long lifetime can be obtained by applying the PCBA1BP (abbreviation) of the present application.

[0563] FIG. 25 This shows the relationship between the current density and brightness characteristics of light-emitting elements 1 and 3. FIG. 26 This displays the relationship between the voltage and brightness characteristics of light-emitting elements 1 and 3. FIG. 27 This displays the relationship between the brightness and current efficiency of light-emitting elements 1 and 3. FIG. 28 This displays the relationship between the voltage and current characteristics of light-emitting elements 1 and 3.

[0564] When the driving voltage of the light-emitting element 3 is 3.4V, the brightness and current values ​​are 1328 cd / m². 2 And 0.78mA. It was found that even when comparing light-emitting element 3 with light-emitting element 1 using NPB for the second layer 1512, light-emitting element 3 using PCBB1BP (abbreviation) for the second layer 1512 showed higher brightness. In addition, it was found that the current efficiency was high when measured by current density or luminance.

[0565] In addition, in the light-emitting element 3, by FIG. 29 The emission spectrum shown exhibits emission wavelengths originating from the blue luminescent material of PCBAPA, but no emission wavelengths originating from the hole-transport material were observed. Therefore, a favorable carrier balance is found in the structure of the luminescent element 3 using the PCBAPA (abbreviation) of the present invention.

[0566] FIG. 30 This shows the relationship between the current density and brightness characteristics of light-emitting elements 1 and 4. FIG. 31 This displays the relationship between the voltage and brightness characteristics of light-emitting elements 1 and 4. FIG. 32 This shows the relationship between the brightness and current efficiency of light-emitting elements 1 and 4. FIG. 33 This displays the relationship between the voltage and current characteristics of light-emitting elements 1 and 4.

[0567] When the driving voltage of the light-emitting element 4 is 3.8V, the brightness and current values ​​are 1328 cd / m². 2 And 1.08mA. It was found that even when the light-emitting element 4 was compared with the light-emitting element 1 which used NPB for the second layer 1512, the light-emitting element 4 which used PCBAF (abbreviation) for the second layer 1512 showed higher brightness.

[0568] Additionally, in the light-emitting element 4, from FIG. 34 The emission spectrum shown shows emission wavelengths originating from the blue luminescent material of PCBAPA, but no emission wavelengths originating from the hole-transport material were observed. Therefore, a favorable carrier balance was found in the structure of the luminescent element 4 using the PCBAF (abbreviation) of the present invention.

[0569] FIG. 35The results of the continuous lighting test, in which the light emitting element 4 was continuously lit by constant current drive with the initial luminance set to 1000 cd / m 2 (the vertical axis indicates relative luminance, assuming 1000 cd / m 2 is 100%). FIG. 35 The results show that even after 160 hours, the light emitting element 4 showed 92% of the initial luminance, and the lifetime was found to be longer than that of the light emitting element 1. Thus, a light emitting element with a long lifetime can be obtained by applying the PCBAF (abbreviation) of the present application.

[0570] FIG. 36 The relationship between the current density and luminance characteristics of the light emitting elements 1 and 5 was shown. FIG. 37 The relationship between the voltage and luminance characteristics of the light emitting elements 1 and 5 was shown. FIG. 38 The relationship between the luminance and current efficiency of the light emitting elements 1 and 5 was shown. FIG. 39 The relationship between the voltage and current characteristics of the light emitting elements 1 and 5 was shown.

[0571] When the driving voltage of the light emitting element 5 was 3.8 V, the luminance and current values were 1398 cd / m 2 and 1.11 mA, respectively. It was found that even when the light emitting element 5 was compared with the light emitting element 1 using NPB for the second layer 1512, the light emitting element 5 using the PCBASF (abbreviation) for the second layer 1512 showed higher luminance. In addition, it was found that the current efficiency was high in terms of current density or luminance.

[0572] In addition, in the light emitting element 5, the emission wavelength originating from the PCBAPA blue light emitting material was observed from the emission spectrum shown in FIG. 40 but the emission wavelength originating from the hole-transporting material was not observed. Thus, it was found that an advantageous carrier balance was achieved in the structure of the light emitting element 5 using the PCBASF (abbreviation) of the present application.

[0573] As described above, it was found that the light emitting elements 2 to 5 formed using the carbazole derivatives of the present application showed the same level of efficiency as the light emitting element 1. Thus, it was found that a light emitting element with high efficiency can be obtained by applying the present application.

[0574] In addition, as another structure of the light emitting element 1 shown in Embodiment 5, the PCBAlBP (abbreviation) was used instead of NPB (abbreviation) used when forming the first layer 1511, co-evaporated with molybdenum (VI) oxide, to form the first layer 1511. Due to the efficiency of this light emitting element 1, the luminance was about 1000 cd / m 2The driving voltage and reliability at the desired brightness are obtained at advantageous values ​​comparable to those of the light-emitting element 8. In embodiment 10, the light-emitting element 8 is formed using a co-evaporated film of NPB and molybdenum oxide (VI) for the hole-injection layer and PCBiNB (abbreviation) for the hole-transport layer. When the driving voltage of the light-emitting element 1 is 3.8V, the brightness and current values ​​are 949 cd / m². 2 With an initial current of 0.65mA, after 1500 hours of driving, the light-emitting element 1 displays 64% of its initial brightness.

[0575] Based on this description, PCBA1BP (abbreviation) was found to be an advantageous material, as it is also a hole-injection material. Furthermore, it was discovered that advantageous properties can also be obtained by using a co-evaporation film containing molybdenum oxide (VI) for the hole-injection layer.

[0576] Alternatively, as an alternative structure for the light-emitting element 2 shown in embodiment 5, PCBA1BP (abbreviation) is used instead of NPB (abbreviation) in forming the first layer 1511, and is co-evaporated with molybdenum oxide (VI) to form the first layer 1511. The efficiency of this light-emitting element 2 is approximately 1000 cd / m². 2 The driving voltage and reliability at the desired brightness are obtained at advantageous values ​​equivalent to those of the light-emitting element 8. In embodiment 10, the light-emitting element 8 is formed by using a co-evaporation film of NPB and molybdenum oxide (VI) for the hole-injection layer and PCBiNB (abbreviation) for the hole-transport layer. When the driving voltage of the light-emitting element 2 is 3.6V, the brightness and current values ​​are 843 cd / m². 2 With an initial voltage of 0.53mA, after 1500 hours of driving, the light-emitting element 2 displays 65% of its initial brightness.

[0577] Based on this description, PCBA1BP (abbreviation) is found to be an advantageous material that can be used simultaneously as a first layer 1511 as a hole-injection layer and a second layer 1512 as a hole-transport layer. Therefore, components can be easily fabricated, and material utilization efficiency can be improved.

[0578] [Implementation Plan 6]

[0579] In embodiment 6, the method for synthesizing the carbazole derivative (biphenyl-4-yl)(phenyl)[4'-(9-phenyl-9H-carbazole-3-yl)biphenyl-4-yl]amine (abbreviation: PCTA1BP) of the present invention, represented by structural formula (15), will be specifically described.

[0580]

[0581] [Step 1: Synthesis of 4-[N-(biphenyl-4-yl)-N-phenyl]aminophenylboronic acid]

[0582] The following (H-1) shows a synthetic scheme of 4-[N-(diphenyl-4-yl)-N- phenyl]aminophenylboronic acid in Step 1.

[0583]

[0584] In a 300-mL three-necked flask, 7.0 g (18 mmol) of 4-bromo-4'-phenyltriphenylamine was added, and the atmosphere in the flask was replaced with nitrogen gas. Then, 80 mL of tetrahydrofuran (abbreviation: THF) was added thereto, and the mixture was stirred at -78°C for 10 minutes. Then, 13 mL (21 mmol) of n-butyllithium hexane solution (1.63 mol / L) was added dropwise to the solution by means of a syringe, and the solution was stirred at -78°C for 1 hour. After stirring, 3.5 mL (31 mmol) of trimethyl borate was added to the reaction mixture, and the mixture was stirred at -78°C for 1 hour and then at room temperature for 24 hours. After the reaction, 100 mL of 1M dilute hydrochloric acid was added to the reaction solution, and the mixture was stirred at room temperature for 1 hour. After stirring, the solution was extracted with ethyl acetate, and the organic layer was washed with a saturated saline solution. After washing, magnesium sulfate was added to the organic layer, and the organic layer was dried. After drying, the magnesium sulfate was removed by suction filtration to obtain a filtrate. The obtained filtrate was concentrated, recrystallized with a chloroform and hexane mixed solvent, and 3.6 g of the target product was obtained with a yield of 56%.

[0585] [Step 2: Synthesis of (diphenyl-4-yl)(phenyl)[4'-(9-phenyl-9H-carbazol-3-yl)diphenyl-4- yl]amine (abbreviation: PCTA1BP)]

[0586] The following (H-2) shows a synthetic scheme of (diphenyl-4-yl)(phenyl)[4'-(9-phenyl-9H-carbazol-3-yl)diphenyl-4-yl]amine in Step 2.

[0587]

[0588] In a 100-mL three-necked flask, 2.2 g (5.5 mmol) of 4-[N-(diphenyl-4-yl)-N- phenyl]aminophenylboronic acid, 2.0 g (5.5 mmol) of 3-(4-bromophenyl)-9-phenyl-9H- carbazole, 10 mg (0.045 mmol) of palladium (II) acetate, and 0.69 g (0.23 mmol) of tris(o-tolyl)phosphine were added, and 10 mL of a potassium carbonate solution (2.0 mol / L) and 20 mL of ethylene glycol dimethyl ether (abbreviation: DME) were added thereto. The mixture was degassed under low pressure with stirring, and the atmosphere in the flask was replaced with nitrogen gas. The mixture was stirred at 90°C for 5 hours. After stirring, toluene was added to the reaction mixture, and the mixture was heated at 90°C.

[0589] After heating, the suspension was separated into an organic layer and an aqueous layer. After separation, the organic layer was washed with a saturated sodium bicarbonate solution and a saturated brine solution. Magnesium sulfate was added to the organic layer, and the organic layer was dried. The mixture was passed through diatomaceous earth, alumina, and Florisil in this order by suction filtration to obtain a filtrate. The obtained filtrate was concentrated to obtain a solid. The obtained filtrate was dissolved and purified by silica gel column chromatography. The silica gel column chromatography was performed by elution with a toluene:hexane = 1:9 mixed solvent as a developing agent, and a toluene:hexane = 2:3 mixed solvent as another developing agent in this order. The obtained fraction was concentrated, and the obtained solid was dissolved in chloroform and purified by high performance liquid chromatography (HPLC) (developing agent, chloroform). The obtained fraction was concentrated, and the obtained solid was recrystallized with a chloroform and hexane mixed solvent to obtain 1.7 g of the target white solid at a yield of 48%.

[0590] The obtained 1.0 g of the white solid was purified by sublimation. Purification by sublimation was performed at 300°C under a reduced pressure of 7.0 Pa at an argon gas flow rate of 4 mL / min for 15 hours. Thus, 0.62 g of a white solid was obtained at a yield of 62%.

[0591] The compound obtained in Step 2 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below. FIG. 45A and 45B showed 1 H NMR spectra. It was found from the measurement results that the carbazole derivative PCTA1BP (abbreviation) of the present application represented by the above structural formula (15) was obtained.

[0592] 1 H NMR (CDC13, 300 MHz): δ (ppm) = 7.02 - 7.79 (m, 32H), 8.19 (d, J = 7.3 Hz, IH), 8.39 (s, IH).

[0593] In addition, the absorption spectrum of PCTA1BP (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 349 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 357 nm.

[0594] In addition, the emission spectrum of PCTA1BP (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 405 nm (excitation wavelength: 320 nm); in the case of a thin film, the maximum emission wavelength was 420 nm (excitation wavelength: 284 nm). Since the measurement method of the absorption spectrum and the emission spectrum was similar to that of Embodiment 1, the description is omitted.

[0595] The results of the thin film measurement by the photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure showed that the HOMO level of PCTA1BP (abbreviation) was -5.49 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.10 eV. Therefore, the energy gap in the solid state was estimated to be 3.10 eV, which indicates that the LUMO level of PCTA1BP (abbreviation) was -2.39 eV.

[0596] The oxidation-reduction reaction characteristics of PCTA1BP (abbreviation) were examined by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted. According to the calculation similar to Embodiment 1, the HOMO level of PCTA1BP (abbreviation) was found to be -5.48 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Therefore, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0597] In addition, the glass transition temperature of PCTA1BP (abbreviation) was examined by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 118°C. In this way, PCTA1BP (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; therefore, PCTA1BP (abbreviation) was found to be a substance that is difficult to crystallize.

[0598] Note that the efficiency of the light-emitting element formed using PCTA1BP (abbreviation) was about 1000 cd / m2at a luminance of about 1000 cd / m2 2 The driving voltage and reliability at a luminance, PCTA1BP (abbreviation) was synthesized for a hole-transporting layer in Embodiment 6 in a manner similar to Embodiment 5; therefore, favorable values equivalent to those of the light-emitting element 8 were obtained, which was formed using PCBBiNB in Embodiment 10. When the driving voltage of this light-emitting element was 3.6 V, the luminance and current values were 1044 cd / m2and 0.67 mA, respectively, and the light-emitting element showed an initial luminance of 52 % after driving for 1100 hours. 2

[0599] [Embodiment 7]

[0600] In Embodiment 7, a method for synthesizing a carbazole derivative, bis(biphenyl-4-yl)[4'-(9-phenyl-9H-carbazol-3-yl)biphenyl-4-yl]amine (abbreviation: PCTBi1BP) represented by Structural Formula (190), will be described in detail.

[0601]

[0602] ​[Step 1: Synthesis of 4-[bis(diphenyl-4-yl)amino]phenylboronic acid]

[0603] The following (I-1) shows a synthesis scheme of 4-[bis(diphenyl-4-yl)amino]phenylboronic acid in Step 1.

[0604]

[0605] In a 300-mL three-necked flask, 6.0 g (13 mmol) of 4-bromo-4',4"-diphenyltriphenylamine was added, and the atmosphere in the flask was replaced with nitrogen gas. Then, 80 mL of tetrahydrofuran (abbreviation: THF) was added thereto, and the mixture was stirred at -78°C for 10 minutes. Then, 10 mL of n-butyllithium hexane solution (1.63 mol / L) was added dropwise to the solution by a syringe, and the solution was stirred at -78°C for 1 hour. After stirring, 2.8 mL (25 mmol) of trimethyl borate was added to the reaction mixture, and the mixture was stirred at -78°C for 1 hour and then at room temperature for 24 hours. After stirring, about 50 mL of dilute hydrochloric acid was added to the reaction mixture, and the mixture was stirred at room temperature for 30 minutes. After stirring, ethyl acetate was added to the mixture, and extraction was performed. After extraction, the organic layer was washed with a saturated saline solution. Then, magnesium sulfate was added to the organic layer, and the organic layer was dried. After drying, the mixture was suction-filtered to obtain a filtrate. The obtained filtrate was concentrated, recrystallized with a chloroform and hexane mixed solvent, and 4.8 g of the target white powdery solid was obtained with a yield of 86%.

[0606] [Step 2: Synthesis of bis(diphenyl-4-yl)[4'-(9-phenyl-9H-carbazol-3-yl)diphenyl-4-yl]amine (abbreviation: PCTBi1BP)]

[0607] The following (I-2) shows a synthesis scheme of bis(diphenyl-4-yl)[4'-(9-phenyl-9H-carbazol-3-yl)diphenyl-4-yl]amine in Step 2.

[0608]

[0609] In a 100-mL three-necked flask, 2.0 g (4.5 mmol) of 4-[bis(diphenyl-4-yl)amino]phenylboronic acid, 1.8 g (4.5 mmol) of 3-(4-bromophenyl)-9-phenyl-9H-carbazole, 10 mg (0.045 mmol) of palladium (II) acetate, and 0.69 g (0.23 mmol) of tris(o-tolyl)phosphine were added, and 10 mL of a potassium carbonate solution (2.0 mol / L) and 20 mL of ethylene glycol dimethyl ether (abbreviation: DME) were added thereto. The mixture was degassed under low pressure with stirring, and the atmosphere in the flask was replaced with nitrogen gas. The mixture was stirred at 90°C for 5 hours. After stirring, toluene was added to the reaction mixture, and the mixture was heated at 90°C.

[0610] After heating, the suspension was separated into an organic layer and an aqueous layer. After separation, the organic layer was washed with a saturated sodium bicarbonate solution and a saturated brine solution. Magnesium sulfate was added to the organic layer, and the organic layer was dried. The mixture was filtered sequentially through diatomaceous earth, alumina, and Florisil to obtain a filtrate. The filtrate was concentrated to obtain a solid. The filtrate was dissolved in toluene and purified by silica gel column chromatography. Elution with toluene as the developing solvent was performed by silica gel column chromatography. The resulting fraction was concentrated, and the solid was recrystallized from a mixture of toluene and hexane to give 2.4 g of the target white solid, in 74% yield.

[0611] The obtained white solid was purified by sublimation. Sublimation purification was carried out under reduced pressure of 7.0 Pa, with an argon flow rate of 3 mL / min, at 340 °C for 20 hours. This yielded 0.70 g of white solid, with a theoretical yield of 1.5 g, representing a yield of 46%.

[0612] By nuclear magnetic resonance (NMR) 1 The compound obtained in step 2 above was measured by ¹H NMR. The measurement results are described below. FIG. 46A and 46B Display in 1 1H NMR spectrum. The measurement results show that the carbazole derivative PCTBi1BP (abbreviation) of this invention, represented by the above structural formula (190), is obtained.

[0613] 1 H NMR (CDCl3, 300MHz): δ (ppm) = 7.18-7.83 (m, 36H), 8.21 (d, J = 7.3Hz, 1H), 8.40 (s, 1H).

[0614] In addition, the absorption spectrum of PCTBi1BP (abbreviation) (measurement range: 200nm-800nm) was measured. In the case of toluene solution, an absorption peak on the long wavelength side was observed at approximately 350nm; in the case of thin film, an absorption peak on the long wavelength side was observed at approximately 357nm.

[0615] In addition, the emission spectrum of PCTBi1BP (abbreviation) was measured (measurement range: 370nm-550nm). In the case of toluene solution, the maximum emission wavelength was 410nm (excitation wavelength: 320nm); in the case of thin film, the maximum emission wavelength was 447nm (excitation wavelength: 340nm). Since the measurement methods for absorption and emission spectra are similar to those in Embodiment 1, descriptions are omitted.

[0616] The results of measuring the thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure showed that the HOMO level of PCTBi1BP (abbreviation) was -5.50 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.14 eV. Therefore, the energy gap in the solid state was estimated to be 3.14 eV, which indicates that the LUMO level of PCTBi1BP (abbreviation) was -2.36 eV.

[0617] The oxidation-reduction reaction characteristics of PCTBi1BP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted.

[0618] According to a calculation similar to that of Embodiment 1, the HOMO level of PCTBi1BP (abbreviation) was found to be = -5.46 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Therefore, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0619] In addition, the glass transition temperature of PCTBi1BP (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 133°C. In this way, PCTBi1BP (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; therefore, PCTBi1BP (abbreviation) was found to be a substance that is difficult to crystallize.

[0620] Note that the efficiency of the light-emitting element formed using PCTBi1BP (abbreviation) was approximately 1000 cd / m2at a luminance of about 1000 cd / m2 2 the driving voltage and the reliability at a luminance, PCTBi1BP (abbreviation) was synthesized for a hole-transport layer in Embodiment 7 in a manner similar to that of Embodiment 5; favorable values equivalent to those of light-emitting element 8, which was formed using PCBBiNP in Embodiment 10, were obtained. When the driving voltage of the light-emitting element was 3.6 V, the luminance and current values were 873 cd / m2and 0.56 mA, respectively, and the light-emitting element showed 80 % of the initial luminance after driving for 110 hours. 2

[0621] [Embodiment 8]

[0622] In Embodiment 8, a method for synthesizing a carbazole derivative represented by Structural Formula (343), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBANB), of the present application will be described specifically.

[0623] ​

[0624] [Step 1: Synthesis of 3-(4-bromophenyl)-9-phenyl-9H-carbazole]

[0625] The following (J-1) shows a synthesis scheme of 3-(4-bromophenyl)-9-phenyl-9H- carbazole in Step 1.

[0626]

[0627] In a 200-mL three-necked flask, 3.7 g (9.9 mmol) of 3-iodo-9-phenyl-9H-carbazole, 2.0 g (9.9 mmol) of 4-bromophenylboronic acid, and 0.61 g (2.0 mmol) of tris(o-tolyl)phosphine were added, and 50 mL of ethyleneglycol dimethyl ether (abbreviation: DME) and 10 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring, and after degassing, the atmosphere in the flask was replaced with nitrogen.

[0628] Then, 0.11 g (0.50 mmol) of palladium (II) acetate was added to the mixture. The mixture was stirred at 80°C for 9.5 hours. After stirring, the mixture was cooled to room temperature, and then washed with water twice. The resulting aqueous layer was extracted with toluene twice. Then, the extract and the organic layer were combined, and then washed with a saturated saline solution. The organic layer was dried with magnesium sulfate, the mixture was naturally filtered, and then the filtrate was concentrated.

[0629] The resulting oily substance was dissolved in about 20 mL of toluene, and the solution was passed through diatomaceous earth, aluminum oxide, and Florisil in this order by suction filtration. The resulting filtrate was concentrated, and the resulting solid was purified by silica gel column chromatography (developing agent, toluene:hexane = 1:4) to obtain 1.9 g of the target white powdery solid at a yield of 49%.

[0630] [Step 2: Synthesis of 4-(1-naphthyl)diphenylamine]

[0631] The following (J-2) shows a synthesis scheme of 4-(1-naphthyl)diphenylamine in Step 2.

[0632]

[0633] In a 200-mL three-necked flask, 12 g (50 mmol) of 4-bromodiphenylamine, 8.6 g (50 mmol) of 1-naphthylboronic acid, 22 mg (0.1 mmol) of palladium (II) acetate, and 60 mg (0.2 mmol) of tris(o-tolyl)phosphine were added, and 50 mL of toluene, 20 mL of ethanol, and 35 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 2 hours under a nitrogen atmosphere to allow the reaction.

[0634] After the reaction, 100 mL of toluene was added to the reaction mixture, and the suspension was sequentially passed through Florisil and celite filters. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane:ethyl acetate = 1 :8: 1). The resulting fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 3.0 g of the target white powder at a yield of 20%.

[0635] [Step 3: Synthesis of 4-(l-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBANB)]

[0636] The following (J-3) shows a synthesis scheme of 4-(l-naphthyl)-4'-(9-phenyl-9H- carbazol-3-yl)-triphenylamine in Step 3.

[0637]

[0638] In a 50-mL three-necked flask, 1.2 g (3.0 mmol) of 3-(4-bromophenyl)-9-phenyl-9H- carbazole, 0.9 g (3.0 mmol) of 4-(l-naphthyl)diphenylamine, 0.5 g (5.0 mmol) of sodium tert-butoxide, and 6.0 mg (0.01 mmol) of bis(dibenzylideneacetone) palladium(0) were added, and 15 mL of anhydrous toluene was added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, 0.06 mL (0.03 mmol) of tri(tert-butyl)phosphine (10% by weight of a hexane solution) was added thereto. The mixture was stirred at 120°C for 4.5 hours under a nitrogen atmosphere to allow the reaction.

[0639] After the reaction, 250 mL of toluene was added to the reaction mixture, and the suspension was sequentially passed through Florisil, silica gel, alumina, and celite filters. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.5 g of the target white powder at a yield of 82%.

[0640] The Rf value of the target substance was 0.34 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1 : 10); that of 3-(4-bromophenyl)-9-phenyl-9H- carbazole was 0.46; and that of 4-(l-naphthyl)diphenylamine was 0.25.

[0641] The target substance was identified by nuclear magnetic resonance method (1H-NMR) as follows. 1The compound obtained by the above Step 3 was measured by H NMR. The measurement results are described below, in FIG. 47A and 47B are shown in 1 H NMR chart. From the measurement results, the carbazole derivative PCBANB (abbreviation) of the present application represented by the above structural formula (343) was obtained.

[0642] 1 H NMR (CDC13, 300 MHz): δ (ppm) = 7.07 (t, J = 6.6 Hz, IH), 7.25-7.67 (m, 26H), 7.84 (d, J = 7.8 Hz, IH), 7.89-7.92 (m, IH), 8.03-8.07 (m, IH), 8.18 (d, J = 7.8 Hz, IH), 8.35 (d, J = 0.9 Hz, IH).

[0643] In addition, the absorption spectrum of PCBANB (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 335 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 341 nm.

[0644] In addition, the emission spectrum of PCBANB (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 410 nm (excitation wavelength: 345 nm); in the case of a thin film, the maximum emission wavelength was 433 nm (excitation wavelength: 341 nm).

[0645] Since the measurement methods of the absorption spectrum and the emission spectrum were similar to those of Embodiment 1, the description is omitted.

[0646] The results of measurement of a thin film by a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBANB (abbreviation) was -5.44 eV. The Tauc chart of the thin film absorption spectrum showed that the absorption limit was 3.25 eV. Therefore, the energy gap in the solid state was estimated to be 3.25 eV, which indicates that the LUMO level of PCBANB (abbreviation) was -2.19 eV.

[0647] The oxidation-reduction reaction characteristics of PCBANB (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted.

[0648] The HOMO level of PCBANB (abbreviation) was found to be -5.44 [eV] by a calculation similar to that of Embodiment 1. In addition, the oxidation peak had a similar value even after 100 cycles. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0649] In addition, the glass transition temperature of PCBANB (abbreviation) was measured by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 115°C. In this way, PCBANB (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; thus, PCBANB (abbreviation) was found to be a substance that is difficult to crystallize.

[0650] In addition, FIGS. 56-59 The measurement results showing the element characteristics of the light-emitting element 6 formed with the inventive carbazole derivative PCBANB (abbreviation) for the hole-transport layer were shown, which was synthesized in Embodiment 8 in a manner similar to that of Embodiment 5. It was found that the inventive hole-transport material for the light-emitting element 6 also showed higher luminance even when compared with NPB of the light-emitting element 1. Note that the light-emitting element 1 was formed in a manner similar to that of Embodiment 5 with 4,4'-bis[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) for the hole-transport layer 151, which was a comparative light-emitting element.

[0651] In addition, in the light-emitting element 6, the hole-transport material was used as the hole-transport layer 152, and the light-emitting material was used as the light-emitting layer 153. FIG. 59 The emission wavelength from the PCBAPA blue light-emitting material was observed in the emission spectrum shown in FIG. 6B, but the emission wavelength from the hole-transport material was not observed. Thus, the inventive hole-transport material was found to achieve a favorable carrier balance in the light-emitting element 6 structure.

[0652] FIG. 60 The results of the continuous lighting test in which the light-emitting element 6 was continuously lit by constant current driving with the initial luminance set to 1000 cd / m 2 (the vertical axis indicates the relative luminance, assuming 1000 cd / m 2 = 100%). It was found from the results in FIG. 6C that the lifetime of the light-emitting element 6 was longer than that of the light-emitting element 1. Thus, a light-emitting element with a long lifetime can be obtained by applying the present invention. FIG. 60

[0653] [Embodiment 9]

[0654] ​In Embodiment 9, a method for synthesizing the inventive carbazole derivative 4,4'-di(l-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)-triphenylamine (abbreviation: PCBNBB) represented by Formula (229) will be specifically described.

[0655]

[0656] [Step 1: Synthesis of 4,4'-dibromo triphenylamine]

[0657] The following (K-1) shows a synthesis scheme of 4,4'-dibromo triphenylamine in Step 1.

[0658]

[0659] In a 500-mL conical flask, 12 g (50 mmol) of triphenylamine was dissolved in 250 mL of a mixed solvent of ethyl acetate, and 18 g (100 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 24 hours. After the completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the obtained filtrate was concentrated and dried to obtain 20 g of the target white solid at a yield of 99%.

[0660] [Step 2: Synthesis of 4,4'-di(l-naphthyl) triphenylamine]

[0661] The following (K-2) shows a synthesis scheme of 4,4'-di(l-naphthyl) triphenylamine in Step 2.

[0662]

[0663] In a 100-mL three-necked flask, 6.0 g (15 mmol) of 4,4'-dibromo triphenylamine, 5.2 g (30 mmol) of 1-naphthaleneboronic acid, 2.0 mg (0.01 mmol) of palladium (II) acetate, and 6.0 mg (0.02 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 20 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 4.5 hours under a nitrogen atmosphere to allow the reaction.

[0664] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 6.4 g of a target white powder at a yield of 86%.

[0665] The Rf value of the target was 0.53, and the Rf value of 4,4'-dibromo triphenylamine was 0.69, by thin layer chromatography (TLC) on silica gel (developing solvent, ethyl acetate:hexane = 1:10).

[0666] [Step 3: Synthesis of 4-bromo-4',4"-di(1-naphthyl)triphenylamine]

[0667] The following (K-3) shows a synthesis scheme of 4-bromo-4',4"-di(1-naphthyl)triphenylamine in Step 3.

[0668]

[0669] In a 300-mL conical flask, 6.4 g (13 mmol) of 4,4'-di(1-naphthyl)triphenylamine was dissolved in 150 mL of ethyl acetate, and then 2.3 g (13 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 24 hours. After the completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the resulting filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized, and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:5). Thus, 1.6 g of a target white powder was obtained at a yield of 22%.

[0670] [Step 4: Synthesis of 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB)]

[0671] The following (K-4) shows a synthesis scheme of 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)-triphenylamine in Step 4.

[0672]

[0673] In a 50-mL three-necked flask, 1.4 g (2.5 mmol) of 4-bromo-4',4"-di(l-naphthyl)triphenylamine, 0.7 g (2.5 mmol) of 9-phenyl-9H-carbazol-3-yl-boronic acid, 4.0 mg (0.02 mmol) of palladium (II) acetate, 6.0 mg (0.02 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 2.5 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 6.5 hours under a nitrogen atmosphere, and the reaction was completed.

[0674] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 0.4 g of a white powder of the target compound at a yield of 22%.

[0675] The compound obtained by Step 4 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 48A and 48B showed 1 the 1H NMR spectrum. It was found from the measurement results that the carbazole derivative PCBNBB (abbreviation) of the present invention represented by the above structural formula (229) was obtained.

[0676] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 7.28-7.72 (m, 30H), 7.85 (d, J = 7.8 Hz, 2H), 7.90-7.93 (m, 2H), 8.06-8.09 (m, 2H), 8.19 (d, J = 7.5 Hz, IH), 8.38 (d, J = 1.5 Hz, IH).

[0677] In addition, the absorption spectrum (measurement range: 200 nm to 800 nm) of PCBNBB (abbreviation) was measured. In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 345 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 355 nm.

[0678] Further, the emission spectrum (abbreviation) of PCBNBB was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 413 nm (excitation wavelength: 355 nm); in the case of a thin film, the maximum emission wavelength was 428 nm (excitation wavelength: 370 nm).

[0679] Since the measurement method of the absorption spectrum and the emission spectrum is similar to that of Embodiment 1, the description is omitted.

[0680] The thin film results measured with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBNBB (abbreviation) was -5.46 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.15 eV. Therefore, the energy gap in the solid state was estimated to be 3.15 eV, which indicates that the LUMO level of PCBNBB (abbreviation) was -2.31 eV.

[0681] The oxidation-reduction reaction characteristics of PCBNBB (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method is similar to that of Embodiment 1, the description is omitted. According to calculations similar to those of Embodiment 1, it was found that the HOMO level of PCBNBB (abbreviation) = -5.43 [eV]. Further, the oxidation peak had a similar value even after 100 cycles. Therefore, it was found that the redox repetition between the oxidized state and the neutral state had favorable characteristics.

[0682] Further, the glass transition temperature of PCBNBB (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, it was found that the glass transition temperature was 136°C. In this way, PCBNBB (abbreviation) has a high glass transition temperature and favorable heat resistance. Further, there was no crystallization peak; therefore, it was found that PCBNBB (abbreviation) is a substance that is difficult to crystallize.

[0683] Further, FIGS. 56-59 The measurement results showing the element characteristics of the light-emitting element 7 formed with the carbazole derivative PCBNBB (abbreviation) of the present application for the hole-transport layer, which was synthesized in Embodiment 9 in a manner similar to that of Embodiment 5, were shown. It was found that the hole-transport material of the present application for the light-emitting element 7 also showed higher luminance even when compared with NPB of the light-emitting element 1. Note that the light-emitting element 1 was formed in a manner similar to that of Embodiment 5 with 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) for the hole-transport layer 151, as a comparative light-emitting element.

[0684] In addition, in the light-emitting element 7, emission wavelengths from the PCBAPA blue light-emitting material are observed in the emission spectrum shown in FIG. 13, but emission wavelengths from the hole-transport material are not observed. Therefore, it was found that the hole-transport material of the present application achieves a favorable carrier balance in the structure of the light-emitting element 7. FIG. 59

[0685] FIG. 60 The results of an uninterrupted lighting test, in which the light-emitting element 7 was continuously lit by driving with a constant current, are shown in FIG. 14, where the initial luminance was set to 1000 cd / m2. 2 (The vertical axis indicates the relative luminance, assuming 1000 cd / m2 2 = 100 %). From the results in FIG. 14, it was found that the light-emitting element 7 has a longer lifetime than the light-emitting element 1. FIG. 60

[0686] [Embodiment 10]

[0687] In Embodiment 10, a method for synthesizing the carbazole derivative 4-(1-naphthyl)-4'-phenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBiNB) represented by Structural Formula (220) will be described specifically.

[0688]

[0689] [Step 1: Synthesis of 4-phenyltriphenylamine]

[0690] The following (L-1) shows a synthetic scheme of 4-phenyltriphenylamine in Step 1.

[0691]

[0692] In a 300-mL three-necked flask, 9.3 g (40 mmol) of 4-bromophenyl, 6.8 g (40 mmol) of diphenylamine, 5.0 g (50 mol) of sodium tert-butoxide, and 10 mg of bis(dibenzylideneacetone) palladium (0) were added, and the atmosphere in the flask was replaced with nitrogen. Then, 100 mL of xylene and 0.6 mL of tri(tert-butyl)phosphine (10 % by weight in hexane) were added to the mixture.

[0693] ​​The mixture was degassed under stirring at low pressure. After replacing the atmosphere with nitrogen, the mixture was stirred at 130°C for 3.5 hours. After stirring, 250 mL of toluene was added to the reaction mixture, and the suspension was filtered through diatomite, alumina and Florisil in this order. The resulting filtrate was washed with water, dried, and magnesium sulfate was added thereto. The mixture was filtered through diatomite, alumina and Florisil in this order to obtain a filtrate. The resulting filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 11 g of the target white powder at a yield of 89%.

[0694] [Step 2: Synthesis of 4-bromo-4'-phenyltriphenylamine]

[0695] The following (L-2) shows a flow of the synthesis of 4-bromo-4'-phenyltriphenylamine in Step 2.

[0696]

[0697] In a 500-mL conical flask, 6.4 g (20 mmol) of 4-phenyltriphenylamine, 250 mL of ethyl acetate and 150 mL of toluene were added, and the mixture was stirred, and then 3.6 g (20 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred for 27.5 hours. After the resulting suspension was washed with water, the moisture was removed by magnesium sulfate. The suspension was concentrated and dried to obtain 7.7 g of the target white powder at a yield of 96%.

[0698] [Step 3: Synthesis of 4-(1-naphthyl)-4'-phenyltriphenylamine]

[0699] The following (L-3) shows a flow of the synthesis of 4-(1-naphthyl)-4'-phenyltriphenylamine in Step 3.

[0700]

[0701] In a 100-mL three-necked flask, 8.0 g (20 mmol) of 4-bromo-4'-phenyltriphenylamine, 3.4 g (20 mmol) of 1-naphthaleneboronic acid, 44 mg (0.2 mmol) of palladium (II) acetate and 60 mg (0.4 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 10 mL of ethanol and 15 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under stirring at low pressure. After degassing, the mixture was stirred at 90°C for 6.5 hours under a nitrogen atmosphere to allow the reaction.

[0702] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 8.6 g of a target white powder at a yield of 97%.

[0703] The Rf value of the target was 0.43, and the Rf value of 4-bromo-4'-phenyltriphenylamine was 0.50, by thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10) development.

[0704] [Step 4: Synthesis of 4-bromo-4'-(1-naphthyl)-4"-phenyl-triphenylamine]

[0705] The following (L-4) shows a synthesis scheme of 4-bromo-4'-(1-naphthyl)-4"-phenyl-triphenylamine in Step 4.

[0706]

[0707] In a 300-mL conical flask, 8.6 g (19 mmol) of 4-(1-naphthyl)-4'-phenyltriphenylamine was dissolved in 150 mL of ethyl acetate, and then 3.4 g (19 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture solution was stirred at room temperature for 24 hours. After the completion of the reaction, the mixture solution was washed with water, and then magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 8.1 g of a target white powder at a yield of 80%.

[0708] [Step 5: Synthesis of 4-(1-naphthyl)-4'-phenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBiNB)]

[0709] The following (L-5) shows a synthesis scheme of 4-(1-naphthyl)-4'-phenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine in Step 5.

[0710]

[0711] In a 50-mL three-necked flask, 1.6 g (3.0 mmol) of 4-bromo-4'- (1-naphthyl) -4"-phenyl-triphenylamine, 0.9 g (30 mmol) of 9-phenyl-9H- carbazole-3-yl-boronic acid, 12 mg (0.06 mmol) of palladium (II) acetate, and 36 mg (0.12 mmol) of tri (o-tolyl) phosphine were added, and 15 mL of toluene, 15 mL of ethanol, and 3 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 2 hours under a nitrogen atmosphere, and the reaction was completed.

[0712] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 0.9 g of a white powder of the target compound at a yield of 44%.

[0713] The Rf value of the target compound was 0.26, and the Rf value of 4-bromo-4'- (1-naphthyl) -4"-phenyl-triphenylamine was 0.45, by thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10).

[0714] The compound obtained by Step 5 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 49A and 49B showed 1 H NMR spectra. It was found from the measurement results that the carbazole derivative PCBBiNB (abbreviation) of the present application represented by the above structural formula (220) was obtained.

[0715] 1 H NMR (CDCI3, 300 MHz): δ (ppm) = 7.27-7.69 (m, 31H), 7.84 (d, J = 7.8 Hz, IH), 7.89-7.92 (m, IH), 8.04-8.08 (m, IH), 8.18 (d, J = 7.8 Hz, IH), 8.36 (d, J = 1.5 Hz, IH).

[0716] In addition, the absorption spectrum of PCBBiNB (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 342 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 351 nm.

[0717] In addition, the emission spectrum of PCBBiNB (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 409 nm (excitation wavelength: 355 nm); in the case of a thin film, the maximum emission wavelength was 433 nm (excitation wavelength: 336 nm).

[0718] Since the measurement method of the absorption spectrum and the emission spectrum was similar to that of Embodiment 1, the description is omitted.

[0719] The results of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBBiNB (abbreviation) was -5.35 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.18 eV. Therefore, the energy gap in the solid state was estimated to be 3.18 eV, which indicates that the LUMO level of PCBBiNB (abbreviation) was -2.17 eV.

[0720] The oxidation-reduction reaction characteristics of PCBBiNB (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted.

[0721] According to a calculation similar to that of Embodiment 1, it was found that the HOMO level of PCBBiNB (abbreviation) = -5.42 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Therefore, it was found that the redox repetition between the oxidized state and the neutral state had favorable characteristics.

[0722] In addition, the glass transition temperature of PCBBiNB (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, it was found that the glass transition temperature was 143°C. In this way, PCBBiNB (abbreviation) had a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; therefore, it was found that PCBBiNB (abbreviation) was a substance that was difficult to crystallize.

[0723] In addition, FIGS. 56-59The results of the measurement of the element characteristics of the light-emitting element 8, which was formed using the carbazole derivative of the present application, PCBBiNB (abbreviation), for the hole-transporting layer, were shown. In Embodiment 10, PCBBiNB was synthesized in a manner similar to that of Embodiment 5. It was found that the hole-transporting material of the present application for the light-emitting element 8 showed higher luminance even when compared with NPB for the light-emitting element 1. Note that the light-emitting element 1 was formed in a manner similar to that of Embodiment 5 using 4,4'-bis[N-(l-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB) for the hole-transporting layer 151, as a comparative light-emitting element.

[0724] In addition, in the light-emitting element 8, the hole-transporting material of the present application was used for the hole-transporting layer 151, and the light-emitting material of the present application, PCBAPA (abbreviation), was used for the light-emitting layer 1512. Thus, the hole-transporting material of the present application and the light-emitting material of the present application were used in combination. FIG. 59 The emission wavelength from the light-emitting material of the present application, PCBAPA, was observed in the emission spectrum shown in Embodiment 10, but the emission wavelength from the hole-transporting material was not observed. Thus, it was found that the hole-transporting material of the present application achieved favorable carrier balance in the light-emitting element 8 structure.

[0725] FIG. 60 The results of the continuous lighting test, in which the light-emitting element 8 was continuously lit by constant current driving, were shown. The initial luminance was set to 1000 cd / m 2 (assuming 1000 cd / m 2 2 as 100 %). From the results in Embodiment 10, it was found that the light-emitting element 8 had a longer lifetime than the light-emitting element 1. Thus, a light-emitting element with a long lifetime can be obtained by applying the present application. FIG. 60

[0726] In addition, as another structure of the light-emitting element 8 shown in Embodiment 10, PCBBiNB (abbreviation) was used instead of NPB (abbreviation) used when the first layer 1511 was formed, and was co-evaporated with molybdenum (VI) oxide to form the first layer 1511. Since the efficiency, driving voltage at about 1000 cd / m 2 2, and reliability of such a light-emitting element 8, favorable values equivalent to those of the light-emitting element 8 were obtained. In Embodiment 10, the light-emitting element 8 was formed by using co-evaporated films of NPB for the hole-injecting layer and molybdenum (VI) oxide and PCBBiNB (abbreviation) for the hole-transporting layer. When the driving voltage of the light-emitting element 8 was 4.2 V, the luminance and current value were 1062 cd / m 2 2 and 0.75 mA, respectively, and the light-emitting element 8 showed 81 % of the initial luminance after 350 hours of driving.

[0727] ​As thus described, the PCBBiNB (abbreviation) was found to be a material favorable in that it can be used as both the first layer 1511 as a hole-injection layer and the second layer 1512 as a hole-transport layer. Thus, an element can be easily produced, and the material can be used with high efficiency.

[0728] [Embodiment 11]

[0729] In Embodiment 11, a method for synthesizing the carbazole derivative of the present application represented by Structural Formula (355) [4'-(l-naphthyl)biphenyl-4-yl](phenyl)[4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine (abbreviation: PCBANT) will be specifically described.

[0730]

[0731] [Step 1: Synthesis of 4-(4-bromophenyl)-4'-phenyl-triphenylamine]

[0732] The following (M-l) shows a synthetic scheme of 4-(4-bromophenyl)-4'-phenyl-triphenylamine in Step 1.

[0733]

[0734] In a 500-mL three-necked flask, 22 g (70 mmol) of 4,4'-dibromo biphenyl, 8.5 g (50 mmol) of diphenylamine, 1.9 g (10 mmol) of cuprous iodide (I), 2.6 g (10 mmol) of 18-crown-6-ether, 6.9 g (50 mmol) of potassium carbonate, and 50 mL of 1,3-dimethyl-3,4,5,6-tetrahydro-2(lH)pyrimidine (abbreviation: DMPU) were added, and the mixture was stirred at 180°C for 37 hours under a nitrogen atmosphere.

[0735] After the reaction, 500 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The obtained filtrate was concentrated and purified by column chromatography on silica gel (developing solvent, toluene:hexane = 1:4). The obtained fraction was concentrated, and hexane and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 5.3 g of the target white powder at a yield of 27%.

[0736] The Rf value of the target substance was 0.5, and the Rf value of 4,4'-dibromo biphenyl was 0.59 by thin layer chromatography (TLC) on silica gel (developing solvent, ethyl acetate:hexane = 1:10).

[0737] [Step 2: Synthesis of [4'-(l-naphthyl)biphenyl-4-yl]diphenylamine]

[0738] The following (M-2) shows a flow of the synthesis of [4'-(l-naphthyl)biphenyl-4-yl]diphenylamine in Step 2.

[0739]

[0740] In a 100-mL three-necked flask, 4.0 g (10 mmol) of 4-(4-bromophenyl)-4'-phenyl- triphenylamine, 1.7 g (10 mmol) of 1-naphthaleneboronic acid, 11 mg (0.05 mmol) of palladium (II) acetate, and 15 mg (0.05 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 10 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 7 hours under a nitrogen atmosphere to allow the reaction.

[0741] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through silica gel, alumina, and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially passed through silica gel, alumina, and celite to obtain a filtrate. The resulting filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 3.6 g of the target white powder at a yield of 80%.

[0742] The Rf value of the target was 0.58, and the Rf value of 4-bromophenyl-4'-phenyl- triphenylamine was 0.65, by thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10) development.

[0743] [Step 3: Synthesis of (4-bromophenyl)[4'-(l-naphthyl)biphenyl-4-yl]amine]

[0744] The following (M-3) shows a flow of the synthesis of (4-bromophenyl)[4'-(l-naphthyl)biphenyl-4-yl]amine in Step 3.

[0745]

[0746] In a 200-mL conical flask, 3.6 g (8.0 mmol) of [4'-(1-naphthyl)biphenyl-4-yl]diphenylamine was dissolved in 100 mL of ethyl acetate, and 1.4 g (8.0 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 72 hours. After the completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the obtained filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 3.9 g of the target white powder at a yield of 93%.

[0747] [Step 4: Synthesis of [4'-(1-naphthyl)biphenyl-4-yl](phenyl)[4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine (abbreviation: PCBANT)]

[0748] The following (M-4) shows a synthesis scheme of [4'-(1-naphthyl)biphenyl-4-yl](phenyl)[4-(9-phenyl-9H-carbazol-3-yl)phenyl]amine in Step 4.

[0749]

[0750] In a 100-mL three-necked flask, 1.6 g (3 mmol) of (4-bromophenyl)[4'-(1-naphthyl)biphenyl-4-yl]amine, 0.8 g (3 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, 6.0 mg (0.03 mmol) of palladium (II) acetate, and 18 mg (0.03 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 3 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 80°C for 6.5 hours under a nitrogen atmosphere to allow the reaction.

[0751] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, and celite to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The obtained fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.2 g of the target white powder at a yield of 60%.

[0752] The Rf value of the target substance developed by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10) was 0.28; and the Rf value of (4-bromophenyl)[4'-(1-naphthyl)biphenyl-4-yl]amine was 0.42.

[0753] The compound obtained by the above Step 4 was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 50A and 50B show 1 H NMR chart. From the measurement results, it was found that the carbazole derivative of the present application represented by the above structural formula (355) was obtained.

[0754] 1 1H NMR (CDC13, 300 MHZ): δ (ppm) = 7.08 (t, J = 7.5 Hz, 1H), 7.20-7.73 (m, 30H), 7.87 (d, J = 8.1 Hz, 1H), 7.92 (d, J = 7.2 Hz, 1H), 8.00 (d, J = 8.4 Hz, 1H), 8.19 (d, J = 7.8 Hz, 1H), 8.35 (d, J = 1.8 Hz, 1H).

[0755] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution (acetonitrile / methanoic acid solution, 80 / 20 vol / vol) of acetonitrile and 0.1% methanoic acid solution was used as a solvent. As a result, a main peak (mode: ES+) of molecular weight 689.30 was detected, confirming that the target PCBANT (abbreviation) was obtained.

[0756] In addition, the absorption spectrum of PCBANT (abbreviation) was measured (measurement range: 200 nm-800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 342 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 351 nm.

[0757] In addition, the emission spectrum of PCBANT (abbreviation) was measured (measurement range: 370 nm-550 nm). In the case of a toluene solution, the maximum emission wavelength was 414 nm (excitation wavelength: 355 nm); in the case of a thin film, the maximum emission wavelength was 342 nm (excitation wavelength: 365 nm). Since the measurement method of the absorption spectrum and the emission spectrum is similar to that of Embodiment 1, the description is omitted.

[0758] The results of thin film measurement by a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure showed that the HOMO level of PCBANT (abbreviation) was -5.38 eV. The Tauc plot of thin film absorption spectrum showed that the absorption limit was 3.11 eV. Therefore, the energy gap in the solid state was estimated to be 3.11 eV, which indicates that the LUMO level of PCBANT (abbreviation) was -2.27 eV.

[0759] The oxidation-reduction reaction characteristics of PCBANT (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted.

[0760] According to a calculation similar to that of Embodiment 1, the HOMO level of PCBANT (abbreviation) was found to be -5.43 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Therefore, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0761] In addition, the glass transition temperature of PCBANT (abbreviation) was detected by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 131°C. In this way, PCBANT (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; therefore, PCBANT (abbreviation) was found to be a substance that is difficult to crystallize.

[0762] Note that, due to the efficiency of the light emitting element formed using PCBANT (abbreviation), the driving voltage at about 1000 cd / m 2 the luminance and reliability, PCBANT was synthesized for the hole-transporting layer in Embodiment 11 in a manner similar to that of Embodiment 5; therefore, favorable values equivalent to those of the light emitting element 8 formed using PCBBiNB in Embodiment 10 were obtained. When the driving voltage of this light emitting element was 4.0 V, the luminance and current values were 1186 cd / m 2 and 0.73 mA, respectively, and after driving for 180 hours, the light emitting element showed 65% of the initial luminance.

[0763] [Embodiment 12]

[0764] In Embodiment 12, the synthesis method of the carbazole derivative 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl)-4'-phenyl-triphenylamine (abbreviation: BCBA1BP) represented by Structural Formula (63) will be described specifically.

[0765]

[0766] [Step 1: Synthesis of 9-(biphenyl-4-yl)-9H-carbazole]

[0767] The following (N-1) shows the synthesis process of 9-(biphenyl-4-yl)-9H-carbazole in step 1.

[0768]

[0769] In a 200-mL three-necked flask, 12 g (50 mmol) of 4-bromobiphenyl, 8.4 g (50 mmol) of carbazole, 230 mg (1 mmol) of palladium acetate (Pd(OAc)(II)), 1.8 g (3.0 mmol) of 1,1-bis(diphenylphosphino)ferrocene (DPPF), and 13 g (180 mmol) of sodium tert-butoxide were added, and the atmosphere in the flask was purged with nitrogen. Then, 80 mL of dehydrated xylene was added to the mixture. The mixture was degassed under low pressure and stirring. Under a nitrogen atmosphere, the mixture was stirred at 120 °C for 7.5 hours to allow the reaction to proceed.

[0770] After the reaction was complete, approximately 600 mL of hot toluene was added to the suspension, and the mixture was filtered twice sequentially through Florisil, alumina, and diatomaceous earth. The resulting filtrate was concentrated, and hexane was added. The mixture was recrystallized to give 14 g of the target white powder, with a yield of 87%.

[0771] [Step 2: Synthesis of 9-(biphenyl-4-yl)-3-bromo-9H-carbazole]

[0772] The following (N-2) shows the synthesis process of 9-(biphenyl-4-yl)-3-bromo-9H-carbazole in step 2.

[0773]

[0774] In a 200-mL Erlenmeyer flask, 3.1 g (10 mmol) of 9-(biphenyl-4-yl)-9H-carbazole was dissolved in 100 mL of chloroform, and then 1.8 g (10 mmol) of N-bromosuccinimide (NBS) was added to the solution. The mixture was then stirred at room temperature for 24 hours. After the reaction was complete, the mixture was washed with water, and magnesium sulfate was added to remove water. The mixture was filtered, and the filtrate was concentrated and dried to give 3.7 g of the target white powder, with a yield of 95%.

[0775] [Step 3: Synthesis of [9-(biphenyl-4-yl)-9H-carbazole-3-yl]boronic acid]

[0776] The following (N-3) shows the synthesis process of [9-(biphenyl-4-yl)-9H-carbazole-3-yl]boronic acid in step 3.

[0777]

[0778] In a 500-mL three-necked flask, 8.0 g (20 mmol) of 9-(4-biphenyl)-3-bromo-9H-carbazole was added, and the atmosphere in the flask was replaced with nitrogen gas. Then, 200 mL of tetrahydrofuran (abbreviation: THF) was added thereto to reach -78°C. Then, 16 mL (24 mmol) of n-butyllithium hexane solution (1.6 mol / L) was added dropwise to the mixture solution, and the solution was stirred for 2 hours. Then, 4.0 mL (40 mmol) of trimethyl borate was added to the reaction mixture, and the mixture was stirred for 2 hours at -78°C and then for 18 hours at room temperature. After the reaction, 50 mL of 1M dilute hydrochloric acid was added to the reaction solution, and the mixture was stirred for 3 hours. The mixture was extracted with toluene, and the resulting organic layer was washed with a saturated saline solution. After washing, magnesium sulfate was added to the organic layer to remove moisture. The suspension was filtered, and the resulting filtrate was concentrated, to which hexane was added. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 6.6 g of the target white powder at a yield of 91%.

[0779] [Step 4: Synthesis of 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl)-4'-phenyl-triphenylamine (abbreviation: BCBA1BP)]

[0780] The following (N-4) shows a synthesis scheme of 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl)-4'-phenyl-triphenylamine in Step 4.

[0781]

[0782] In a 50-mL three-necked flask, 1.2 g (3.0 mmol) of 4-bromo-4'-phenyl-triphenylamine, 1.1 g (3.0 mmol) of [9-(biphenyl-4-yl)-9H-carbazol-3-yl]boronic acid, 6.0 mg (0.03 mmol) of palladium (II) acetate, and 18 mg (0.06 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 3 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under stirring at low pressure. After degassing, the mixture was stirred at 90°C for 6.5 hours under a nitrogen atmosphere to allow the reaction.

[0783] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.5 g of the target white powder at a yield of 79%.

[0784] The Rf value of the target was 0.45, and the Rf value of 4-bromo-4'-phenyl- triphenylamine was 0.68 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10).

[0785] The compound obtained by Step 4 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 51A and 51B show 1 H NMR spectra. It was found from the measurement results that the carbazole derivative BCBA1BP (abbreviation) of the present application represented by the above structural formula (63) was obtained.

[0786] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 7.06 (t, J = 7.2 Hz, 1H), 7.20-7.72 (m, 29H), 7.83 (d, J = 8.4 Hz, 2H), 8.19 (d, J = 7.8 Hz, 1H), 8.35 (s, 1H).

[0787] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution (acetonitrile / 0.1% formic acid solution, mixing ratio of acetonitrile / formic acid solution, 80 / 20 vol / vol) was used as a solvent. As a result, a main peak of a molecular weight of 638.27 (mode: ES+) was detected, which confirmed that the target BCBA1BP (abbreviation) was obtained.

[0788] In addition, the absorption spectrum of PCBA1BP (abbreviation) (measurement range: 200 nm to 800 nm) was measured. In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 336 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 342 nm.

[0789] Further, the emission spectrum (abbreviation) of PCBA1BP was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 394 nm (excitation wavelength: 350 nm); in the case of a thin film, the maximum emission wavelength was 408 nm (excitation wavelength: 301 nm). Since the measurement method of the absorption spectrum and the emission spectrum was similar to that of Embodiment 1, the description is omitted.

[0790] The results of the thin film measurement with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBA1BP (abbreviation) was -5.48 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.19 eV. Therefore, the energy gap in the solid state was estimated to be 3.19 eV, which indicates that the LUMO level of PCBA1BP (abbreviation) was -2.29 eV.

[0791] The oxidation-reduction reaction characteristics of PCBA1BP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted.

[0792] According to a calculation similar to that of Embodiment 1, it was found that the HOMO level of PCBA1BP (abbreviation) = -5.43 [eV]. Further, the oxidation peak had a similar value even after 100 cycles. Therefore, it was found that the redox repetition between the oxidized state and the neutral state had favorable characteristics.

[0793] Further, the glass transition temperature of PCBA1BP (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, it was found that the glass transition temperature was 122°C. In this way, PCBA1BP (abbreviation) had a high glass transition temperature and favorable heat resistance. Further, there was no crystallization peak; therefore, it was found that PCBA1BP (abbreviation) was a substance that was difficult to crystallize.

[0794] Note that, due to the efficiency of the light-emitting element formed with PCBA1BP (abbreviation), the luminance at about 1000 cd / m2 2 the driving voltage and the reliability at a luminance, PCBA1BP was synthesized for the hole-transporting layer in Embodiment 12 in a manner similar to that of Embodiment 5; therefore, favorable values equivalent to those of the light-emitting element 8 formed with PCBBiNB in Embodiment 10 were obtained. When the driving voltage of this light-emitting element was 4.0 V, the luminance and current values were 1031 cd / m 2 and 0.72 mA, respectively, and after driving for 180 hours, the light-emitting element showed 89 % of the initial luminance.

[0795] [Embodiment 13]

[0796] In Embodiment 13, a method for synthesizing the carbazole derivative of the present application represented by Structural Formula (364), 4-[9-(diphenyl-4-yl)-9H-carbazol-3-yl)-4'-(1-naphthyl)triphenylamine (abbreviation: BCBANB), will be specifically described.

[0797]

[0798] [Step 1: Synthesis of 4-bromo triphenylamine]

[0799] The following (O-1) shows a synthesis scheme of 4-bromo triphenylamine in Step 1.

[0800]

[0801] To a solution of 54.0 g (220 mmol) of triphenylamine in 1.5 L of ethyl acetate was added 35.6 g (200 mmol) of N-bromosuccinimide (abbreviation: NBS). Then, the mixture was stirred for 24 hours. After the resulting suspension was concentrated to 1 L, the concentrated suspension was washed with 1 L of a 5% sodium acetate aqueous solution. After the washing, the solution was further concentrated to about 50 mL. Then, methanol was added to the concentrated solution to precipitate the solution, and the resulting precipitate was filtered and dried to obtain 46.5 g of the target white powder at a yield of 73%.

[0802] [Step 2: Synthesis of 4-(1-naphthyl)triphenylamine]

[0803] The following (O-2) shows a synthesis scheme of 4-(1-naphthyl)triphenylamine in Step 2.

[0804]

[0805] In a 20 mL three-necked flask, 9.7 g (30 mmol) of 4-bromo triphenylamine, 5.7 g (33 mmol) of 1-naphthaleneboronic acid, 67 mg (0.3 mmol) of palladium (II) acetate, and 91 g (0.3 mmol) of tris(o-tolyl)phosphine were added, and 20 mL of toluene, 20 mL of ethanol, and 20 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 2 hours under a nitrogen atmosphere to allow the reaction.

[0806] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially passed through Florisil, silica gel, and celite filters. The resulting filtrate was sequentially washed with sodium bicarbonate solution and water, and magnesium sulfate was added thereto, and the filtrate was dried. After drying, the suspension was sequentially passed through Florisil, alumina, silica gel, and celite filters to obtain a filtrate. The resulting filtrate was concentrated and dried to obtain 11 g of a target light yellow solid at a yield of 99%.

[0807] The Rf value of the target was 0.48, and the Rf value of 4-bromo triphenylamine was 0.55 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10).

[0808] The compound obtained by the above Step 2 was measured by nuclear magnetic resonance method (1H NMR). 1 It was found from the measurement result that the compound of the present application represented by the above structural formula (364) was obtained.

[0809] 1 1H NMR (CDC13, 300 MHz): δ (ppm) = 7.07 (t, J = 7.5 Hz, 1H), 7.22-7.61 (m, 21H), 7.83 (d, J = 7.8 Hz, 1H), 7.88-7.91 (m, 1H), 8.02-8.05 (m, 1H).

[0810] [Step 3: Synthesis of 4-bromo-4'-(1-naphthyl)triphenylamine]

[0811] The following (O-3) shows a flow of synthesis of 4-bromo-4'-(1-naphthyl)triphenylamine in Step 3.

[0812]

[0813] In a 500-mL recovery flask, 11 g (30 mmol) of 4-(1-naphthyl)triphenylamine was dissolved in 300 mL of ethyl acetate, and 5.3 g (30 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture solution was stirred at room temperature for 168 hours. After the completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 7.8 g of a target white powder at a yield of 43%.

[0814] [Step 4: Synthesis of 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl]-4'-(1-naphthyl)triphenylamine (abbreviation: BCBANB)]

[0815] The following (O-4) shows a flow of the synthesis of 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl]-4'-(1-naphthyl)triphenylamine in Step 4.

[0816]

[0817] In a 100-mL three-necked flask, 1.35 g (3.0 mmol) of 4-bromo-4'-(1-naphthyl)triphenylamine, 1.1 g (3.0 mmol) of [9-(biphenyl-4-yl)-9H-carbazol-3-yl]boronic acid, 6.0 mg (0.02 mmol) of palladium (II) acetate, and 9.0 mg (0.06 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 3 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 3 hours under a nitrogen atmosphere to allow the reaction.

[0818] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The obtained filtrate was concentrated and purified by column chromatography on silica gel (developing solvent, toluene:hexane = 1:4). The obtained fraction was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.0 g of the target white powder at a yield of 50%.

[0819] The Rf value of the target substance was 0.45 by thin layer chromatography (TLC) on silica gel (developing solvent, ethyl acetate:hexane = 1:10); the Rf value of 4-bromo-4'-(1-naphthyl)triphenylamine was 0.66.

[0820] The compound obtained by Step 4 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 52A and 52B showed 1 the H NMR spectrum. It was found from the measurement results that the carbazole derivative BCBANB (abbreviation) of the present invention represented by the above structural formula (364) was obtained.

[0821] 1H NMR (CDC13, 300 MHz): δ (ppm) = 7.08 (t, J = 6.9 Hz, 1H), 7.28-7.71 (m, 28H), 7.82-7.86 (m, 3H), 7.89-7.92 (m, 1H), 8.04-8.07 (m, 1H), 8.20 (d, J = 7.8 Hz, 1H), 8.37 (d, J = 1.2 Hz, 1H).

[0822] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution (acetonitrile / methanoic acid solution, 80 / 20 vol / vol) was used as a solvent. As a result, a main peak of 556.52 (mode: ES+) was detected, which confirmed that the target BCBANB (abbreviation) was obtained.

[0823] In addition, the absorption spectrum of BCBANB (abbreviation) was measured (measurement range: 200 nm-800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 335 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 344 nm.

[0824] In addition, the emission spectrum of BCBANB (abbreviation) was measured (measurement range: 370 nm-550 nm). In the case of a toluene solution, the maximum emission wavelength was 410 nm (excitation wavelength: 345 nm); in the case of a thin film, the maximum emission wavelength was 422 nm (excitation wavelength: 328 nm).

[0825] Since the measurement method of the absorption spectrum and the emission spectrum is similar to that of Embodiment 1, the description is omitted.

[0826] The results of measurement of a thin film with a spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of BCBANB (abbreviation) was -5.42 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.19 eV. Therefore, the energy gap in the solid state was estimated to be 3.19 eV, which indicates that the LUMO level of BCBANB (abbreviation) was -2.23 eV.

[0827] The oxidation-reduction reaction characteristics of BCBANB (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method is similar to that of Embodiment 1, the description is omitted.

[0828] The HOMO level of BCBANB (abbreviation) was found to be -5.45 [eV] by a calculation similar to that of Embodiment 1. In addition, the oxidation peak had a similar value even after 100 cycles. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0829] In addition, the glass transition temperature of BCBANB (abbreviation) was measured by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 1300C. In this way, BCBANB (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; thus, BCBANB (abbreviation) was found to be a substance that is difficult to crystallize.

[0830] Note that the efficiency of the light-emitting element formed using BCBANB (abbreviation) was about 1000 cd / m2at a driving voltage of 4.0 V, which is a value similar to that of the light-emitting element 8 formed using PCBBiNB in Embodiment 10. 2 The driving voltage and reliability at a luminance of 1000 cd / m2were measured in Embodiment 13 in a manner similar to Embodiment 5, in which BCBANB was synthesized for the hole-transport layer; favorable values equivalent to those of the light-emitting element 8 formed using PCBBiNB in Embodiment 10 were obtained. When the driving voltage of the light-emitting element was 4.0 V, the luminance and current values were 848 cd / m2and 0.52 mA, respectively. 2

[0831] [Embodiment 14]

[0832] In Embodiment 14, a method for synthesizing a carbazole derivative of the present application, 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl)-4'-(1-naphthyl)4"-phenyl- triphenylamine (abbreviation: BCBBiNB) represented by Structural Formula (366) will be described specifically.

[0833]

[0834] [Step 1: Synthesis of 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl)-4'-(1-naphthyl)4"-phenyl- triphenylamine (abbreviation: BCBBiNB)]

[0835] The following (P-1) shows a synthesis scheme of 4-[9-(biphenyl-4-yl)-9H-carbazol-3-yl)-4'-(1-naphthyl)4"-phenyl-triphenylamine in Step 1.

[0836]

[0837] ​In a 100-mL three-necked flask, 1.6 g (3.0 mmol) of 4-bromo-4'- (1-naphthyl)-4"-phenyl-triphenylamine, 1.1 g (3.0 mmol) of [9-(biphenyl-4-yl)- 9H-carbazol-3-yl]boronic acid, 6.0 mg (0.03 mmol) of palladium (II) acetate, and 18 mg (0.03 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 3 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 6.5 hours under a nitrogen atmosphere, and the reaction was completed.

[0838] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.4 g of the target white powder at a yield of 60%.

[0839] The Rf value of the target was 0.26 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10); and the Rf value of 4-bromo-4'- (1-naphthyl)-4"-phenyl-triphenylamine was 0.46.

[0840] The compound obtained by Step 1 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 53A and 53B showed 1 H NMR spectra. It was found from the measurement results that the carbazole derivative BCBBiNB (abbreviation) of the present application represented by the above structural formula (366) was obtained.

[0841] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 7.30-7.71 (m, 33H), 7.82-7.86 (m, 3H), 7.90-7.93 (m, 1H), 8.05-8.08 (m, 1H), 8.20 (d, J = 7.8 Hz, 1H), 8.38 (d, J = 1.5 Hz, 1H).

[0842] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution (acetonitrile / methanoic acid solution mixture ratio, 80 / 20 vol / vol) of acetonitrile and 0.1% methanoic acid solution was used as a solvent. As a result, a main peak of molecular weight 765.32 (mode: ES+) was detected, confirming that the target BCBBiNB (abbreviation) was obtained.

[0843] In addition, the absorption spectrum of BCBBiNB (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 342 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 351 nm.

[0844] In addition, the emission spectrum of BCBBiNB (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 409 nm (excitation wavelength: 355 nm); in the case of a thin film, the maximum emission wavelength was 433 nm (excitation wavelength: 336 nm).

[0845] Since the measurement method of the absorption spectrum and the emission spectrum is similar to that of Embodiment 1, the description is omitted.

[0846] The results of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of BCBBiNB (abbreviation) was -5.35 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.18 eV. Therefore, the energy gap in the solid state was estimated to be 3.18 eV, which indicates that the LUMO level of BCBBiNB (abbreviation) was -2.17 eV.

[0847] The oxidation-reduction reaction characteristics of BCBBiNB (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method is similar to that of Embodiment 1, the description is omitted.

[0848] According to a calculation similar to that of Embodiment 1, it was found that the HOMO level of BCBBiNB (abbreviation) = -5.42 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Therefore, it was found that the redox repetition between the oxidized state and the neutral state had a favorable characteristic.

[0849] Further, the glass transition temperature of BCBBiNB (abbreviation) was measured by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement result, the glass transition temperature was found to be 143°C. In this way, BCBBiNB (abbreviation) has a high glass transition temperature and favorable heat resistance. Further, there was no crystallization peak; thus, BCBBiNB (abbreviation) was found to be a substance that is difficult to crystallize.

[0850] Note that the efficiency of the light-emitting element formed using BCBBiNB (abbreviation) was about 1000 cd / m 2 the luminance and current value were 996 cd / m 2 and 0.59 mA, respectively, when the driving voltage of the light-emitting element was 4.0 V. After driving for 180 hours, the light-emitting element showed an initial luminance of 84 %.

[0851] [Embodiment 15]

[0852] In Embodiment 15, a method for synthesizing a carbazole derivative of the present application, 4-{9-[4-(1-naphthyl)phenyl]-9H-carbazol-3-yl}-4'-phenyl- triphenylamine (abbreviation: NBCBA1BP), represented by Structural Formula (386) will be described specifically.

[0853]

[0854] [Step 1: Synthesis of 9-(4-bromophenyl)-9H-carbazole]

[0855] The following (Q-1) shows a synthesis scheme of 9-(4-bromophenyl)-9H-carbazole in Step 1.

[0856]

[0857] In a 300-mL three-necked flask, 56 g (240 mmol) of 1,4-dibromobenzene, 31 g (180 mmol) of 9H-carbazole, 4.6 g (24 mmol) of cuprous iodide (I), 2.1 g (8.0 mmol) of 18-crown-6-ether, 66 g (480 mmol) of potassium carbonate, and 8 mL of 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (abbreviation: DMPU) were added, and the mixture was stirred at 180°C for 6 hours under a nitrogen atmosphere.

[0858] After the reaction, the suspension was filtered, and the filtrate was washed with dilute hydrochloric acid, saturated sodium bicarbonate solution and saturated brine solution in this order. Then, water was removed by magnesium sulfate. The suspension was filtered, and the obtained filtrate was concentrated and purified by column chromatography on silica gel (eluent, toluene:hexane = 9:1). The obtained fraction was concentrated, and chloroform and hexane were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 21 g of the target light brown flaky crystals at a yield of 35%.

[0859] [Step 2: Synthesis of 9-[4-(1-naphthyl)phenyl]-9H-carbazole]

[0860] The following (Q-2) shows a flow of the synthesis of 9-[4-(1-naphthyl)phenyl]-9H-carbazole in Step 2.

[0861]

[0862] In a 100-mL three-necked flask, 4.8 g (15 mmol) of 9-(4-bromophenyl)-9H-carbazole, 2.6 g (15 mmol) of 1-naphthaleneboronic acid, 2.0 mg (0.01 mmol) of palladium (II) acetate and 6.0 mg (0.02 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 10 mL of ethanol and 10 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 9 hours under a nitrogen atmosphere to allow the reaction.

[0863] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was filtered through Florisil and celite in this order. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove water. The suspension was filtered through Florisil, alumina, silica gel and celite in this order to obtain a filtrate. The obtained filtrate was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 5.0 g of the target white powder at a yield of 90%.

[0864] The Rf value of the target substance developed by thin layer chromatography (TLC) on silica gel (eluent, ethyl acetate:hexane = 1:10) was 0.46; and the Rf value of 9-(4-bromophenyl)-9H-carbazole was 0.54.

[0865] [Step 3: Synthesis of 3-bromo-9-[4-(1-naphthyl)phenyl]-9H-carbazole]

[0866] The following (Q-3) shows a flow of the synthesis of 3-bromo-9-[4-(1-naphthyl)phenyl]-9H-carbazole in Step 3.

[0867]

[0868] In a 300-mL flask, 5.0 g (14 mmol) of 9-[4-(1-naphthyl)phenyl]-9H-carbazole was dissolved in a mixed solvent of 50 mL of toluene and 250 mL of ethyl acetate, and 2.5 g (14 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 168 hours. After the reaction was completed, the mixture solution was filtered through Florisil and celite in this order. Then, the obtained filtrate was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the obtained filtrate was concentrated, and hexane was added thereto. Then, the mixture was treated with ultrasonic waves to obtain 6.1 g of the target white powder at a yield of 99%.

[0869] [Step 4: Synthesis of 9-[4-(1-naphthyl)phenyl]-9H-carbazole-3-boronic acid]

[0870] The following (Q-4) shows a synthesis scheme of 9-[4-(1-naphthyl)phenyl]-9H-carbazole-3-boronic acid in Step 4.

[0871]

[0872] In a 500-mL three-necked flask, 5.0 g (14 mmol) of 3-bromo-9-[4-(1-naphthyl)phenyl]-9H-carbazole was added, and the atmosphere in the flask was replaced with nitrogen. Then, 200 mL of tetrahydrofuran (abbreviation: THF) was added thereto to reach -78°C. 11 mL (17 mmol) of n-butyllithium hexane solution (1.6 mol / L) was added dropwise to the mixture solution, and the solution was stirred for 4 hours. Then, 2.7 mL (27 mmol) of trimethyl borate was added to the reaction mixture, and the mixture was stirred at -78°C for 2 hours and at room temperature for 16 hours. After the reaction, 50 mL of 1M diluted hydrochloric acid was added to the reaction solution, and the mixture was stirred for 4 hours. The mixture was extracted with toluene, and the obtained organic layer was washed with a saturated saline solution. After washing, magnesium sulfate was added to the organic layer to remove moisture. The suspension was filtered, and the obtained filtrate was concentrated, and chloroform and hexane were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 3.5 g of the target white powder at a yield of 63%.

[0873] [Step 5: Synthesis of 4-{9-[4(1-naphthyl)phenyl]-9H-carbazol-3-yl}-4'-phenyl- triphenylamine (abbreviation: NBCBA1BP)]

[0874] The following (Q-5) shows a synthesis scheme of 4-{9-[4(1-naphthyl)phenyl]-9H-carbazol-3-yl}-4'-phenyl-triphenylamine in Step 5.

[0875]

[0876] In a 50-mL three-necked flask, 1.0 g (2.5 mmol) of 4-bromo-4'-phenyl- triphenylamine, 1.0 g (2.5 mmol) of 9-[4-(l-naphthyl)phenyl]-9H-carbazole-3- boronic acid, 4.0 mg (0.02 mmol) of palladium (II) acetate, and 6.0 mg (0.02 mmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 5 mL of ethanol, and 2.5 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 13 hours under a nitrogen atmosphere to allow the reaction to proceed.

[0877] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.2 g of a target white powder at a yield of 70%.

[0878] The Rf value of the target was 0.41, and the Rf value of 4-bromo-4'-phenyl- triphenylamine was 0.62, by thin layer chromatography (TLC) on silica gel (developing solvent, ethyl acetate:hexane = 1:10).

[0879] The compound obtained by Step 5 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 54A and 54B showed 1 H NMR spectra. From the measurement results, the carbazole derivative of the present application, NBCBA1BP (abbreviation) represented by the above structural formula (386) was obtained.

[0880] 1 H NMR (CDC13, 300 MHz): δ (ppm) = 7.06 (t, J = 6.6 Hz, IH), 7.21-7.77 (m, 30H), 7.92-7.98 (m, 2H), 8.04-8.08 (m, IH), 8.22 (d, J = 7.8 Hz, IH), 8.37 (d, J = 1.5 Hz, IH).

[0881] In addition, the absorption spectrum of NBCBA1BP (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 333 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 340 nm.

[0882] In addition, the emission spectrum of NBCBA1BP (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 393 nm (excitation wavelength: 350 nm); in the case of a thin film, the maximum emission wavelength was 488 nm (excitation wavelength: 302 nm).

[0883] Since the measurement method of the absorption spectrum and the emission spectrum is similar to that of Embodiment 1, the description is omitted.

[0884] The results of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of NBCBA1BP (abbreviation) was -5.53 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption edge was 3.22 eV. Thus, the energy gap in the solid state was estimated to be 3.22 eV, which indicates that the LUMO level of NBCBA1BP (abbreviation) was -2.31 eV.

[0885] The oxidation-reduction reaction characteristics of NBCBA1BP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method is similar to that of Embodiment 1, the description is omitted.

[0886] According to a calculation similar to that of Embodiment 1, the HOMO level of NBCBA1BP (abbreviation) was found to be -5.43 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0887] In addition, the glass transition temperature of NBCBA1BP (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 132°C. In this way, NBCBA1BP (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; thus, NBCBA1BP (abbreviation) was found to be a substance that is difficult to crystallize.

[0888] Note that the efficiency of a light-emitting element formed using NBCBA1BP (abbreviation) was about 1000 cd / m2 2The driving voltage and reliability at luminance, in Embodiment 15, NBCBA1BP was synthesized for the hole-transporting layer in a similar manner to Embodiment 5; favorable values equivalent to those of the light-emitting element 8 formed with PCBBiNB in Embodiment 10 were obtained. When the driving voltage of this light-emitting element was 3.6 V, the luminance and current values were 773 cd / m2and 0.47 mA, respectively. 2 and 0.47 mA.

[0889] [Embodiment 16]

[0890] In Embodiment 16, a method for synthesizing the carbazole derivative 4-[9-(l-naphthyl)-9H-carbazol-3-yl]-4'-phenyl-triphenylamine (abbreviation: NCBA1BP) represented by Structural Formula (395) will be described specifically.

[0891]

[0892] [Step 1: Synthesis of 9-(l-naphthyl)-9H-carbazole]

[0893] The following (R-1) shows a synthetic flow of 9-(l-naphthyl)-9H-carbazole in Step 1.

[0894]

[0895] In a 500-mL three-necked flask, 21 g (100 mmol) of 1-bromonaphthalene, 17 g (100 mmol) of carbazole, 0.1 g (5.0 mmol) of cuprous iodide (I), 0.7 g (2.5 mmol) of 18-crown-6-ether, 33 g (240 mmol) of potassium carbonate, and 80 mL of 1,3-dimethyl-3,4,5,6-tetrahydro-2(lH)pyrimidine (abbreviation: DMPU) were added, and the mixture was stirred at 170°C for 6 hours under a nitrogen atmosphere. Then, 10 g (50 mmol) of 1-bromonaphthalene, 2.0 g (10 mmol) of cuprous iodide (I), and 2.6 g (10 mmol) of 18-crown-6-ether were further added to the reaction mixture, and the mixture was stirred at 170°C for 7.5 hours. Then, 10 g (50 mmol) of 1-bromonaphthalene was further added to the reaction mixture, and the mixture was stirred at 180°C for 6 hours.

[0896] After the reaction, about 200 mL of toluene and about 100 mL of hydrochloric acid (1 mol / L) were added to the reaction mixture, and the mixture was filtered through celite. The resulting filtrate was filtered through Florisil and celite. The resulting filtrate was separated into an organic layer and an aqueous layer. The organic layer was washed with hydrochloric acid (1 mol / L) and water in this order, and magnesium sulfate was added to remove moisture. The suspension was filtered through Florisil and celite. Then, the resulting filtrate was concentrated, hexane was added to the resulting oily substance, the mixture was treated with ultrasonic waves, and then recrystallized to obtain 22 g of the target white powder at a yield of 75%.

[0897] The Rf value of the target substance developed by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10) was 0.61; the Rf value of 1-bromonaphthalene was 0.74; and the Rf value of carbazole was 0.24.

[0898] [Step 2: Synthesis of 3-bromo-9-(1-naphthyl)-9H-carbazole]

[0899] The following (R-2) shows a synthesis flow of 3-bromo-9-(1-naphthyl)-9H-carbazole in Step 2.

[0900]

[0901] In a 500-mL conical flask, after 5.9 g (20 mmol) of 9-(1-naphthyl)-9H-carbazole was dissolved in a mixed solvent of 50 mL of toluene and 50 mL of ethyl acetate, 3.6 g (20 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 170 hours. After the reaction was completed, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the resulting filtrate was concentrated and dried to obtain 7.4 g of the target white powder at a yield of 99%.

[0902] The Rf value of the target substance developed by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10) was 0.43; and the Rf value of 9-(1-naphthyl)-9H-carbazole was 0.35.

[0903] [Step 3: Synthesis of 9-(1-naphthyl)-9H-carbazole-3-boronic acid]

[0904] The following (R-3) shows a synthesis flow of 9-(1-naphthyl)-9H-carbazole-3-boronic acid in Step 3.

[0905]

[0906] In a 500-mL three-necked flask, 3.7 g (10 mmol) of 9-(1-naphthyl)-9H-carbazole was added, and the atmosphere in the flask was replaced with nitrogen gas. Then, 200 mL of tetrahydrofuran (abbreviation: THF) was added thereto, and the mixture was stirred at -78°C. Then, 7 mL (13 mmol) of n-butyllithium hexane solution (1.6 mol / L) was added dropwise to the mixture solution, and the solution was stirred for 2 hours. Then, 2 mL (20 mmol) of trimethyl borate was added to the reaction mixture, and the mixture was stirred at -78°C for 3 hours and at room temperature for 16 hours. After the reaction, 50 mL of 1M dilute hydrochloric acid was added to the reaction solution, and the mixture was stirred for 4 hours. The mixture was extracted with ethyl acetate, and the obtained organic layer was washed with a saturated saline solution. After washing, magnesium sulfate was added to the organic layer to remove moisture. The suspension was filtered, and the obtained filtrate was concentrated, to which chloroform and hexane were added. The mixture was treated with ultrasonic waves, and then recrystallized, to obtain 2.6 g of the target yellow powder at a yield of 78%.

[0907] [Step 4: Synthesis of 4-[9-(1-naphthyl)-9H-carbazol-3-yl]-4'-phenyl- triphenylamine (abbreviation: NCBA1BP)]

[0908] The following (R-4) shows a synthesis scheme of 4-[9-(1-naphthyl)-9H-carbazol-3-yl]-4'-phenyl-triphenylamine (abbreviation: NCBA1BP) in Step 4.

[0909]

[0910] In a 50-mL three-necked flask, 1.2 g (3.0 mmol) of 4-bromo-4'-phenyl-triphenylamine, 1.0 g (3.0 mmol) of 9-(1-naphthyl)-9H-carbazole-3-boronic acid, 6.0 mg (0.03 mmol) of palladium (II) acetate, and 0.03 mg (18 mmol) of tri(o-tolyl)phosphine were added, and 15 mL of toluene, 5 mL of ethanol, and 3 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under stirring at low pressure. After degassing, the mixture was stirred at 90°C for 6.5 hours under a nitrogen atmosphere, and the reaction was completed.

[0911] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated. Purification was performed by silica gel column chromatography (developing solvent, toluene:hexane = 1:3). The resulting fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 0.5 g of the target white powder at a yield of 25%.

[0912] The Rf value of the target by thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10) was 0.34; and the Rf value of 4-bromo-4'-phenyl- triphenylamine was 0.54.

[0913] The compound obtained by Step 4 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 55A and 55B showed 1 the H NMR spectrum. From the measurement results, the carbazole derivative NCBA1BP (abbreviation) of the present application represented by the above structural formula (395) was obtained.

[0914] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 7.00-7.07 (m, 3H), 7.19-8.00 (m, 25H), 8.03-8.07 (m, 2H), 8.22-8.25 (m, 1H), 8.40 (d, J = 1.5, 1H).

[0915] In addition, the absorption spectrum of NCBA1BP (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 333 nm; and in the case of a thin film, an absorption peak on the long wavelength side was observed at about 340 nm.

[0916] In addition, the emission spectrum of NCBA1BP (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 392 nm (excitation wavelength: 345 nm); and in the case of a thin film, the maximum emission wavelength was 426 nm (excitation wavelength: 328 nm). Since the measurement method of the absorption spectrum and the emission spectrum was similar to that of Embodiment 1, the description is omitted.

[0917] The results of thin film measurement by a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure showed that the HOMO level of NCBA1BP (abbreviation) was -5.44 eV. The Tauc plot of thin film absorption spectrum showed that the absorption limit was 3.19 eV. Therefore, the energy gap in the solid state was estimated to be 3.19 eV, which indicates that the LUMO level of NCBA1BP (abbreviation) was -2.25 eV.

[0918] The oxidation-reduction reaction characteristics of NCBA1BP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description was omitted. According to calculation similar to Embodiment 1, it was found that the HOMO level of NCBA1BP (abbreviation) = -5.43 [eV]. In addition, the oxidation peak had a similar value even after 100 cycles. Therefore, it was found that the redox repetition between the oxidized state and the neutral state had favorable characteristics.

[0919] In addition, the glass transition temperature of NCBA1BP (abbreviation) was detected by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, it was found that the glass transition temperature was 128°C. In this way, NCBA1BP (abbreviation) had a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; therefore, it was found that NCBA1BP (abbreviation) was a substance that was difficult to crystallize.

[0920] Note that the efficiency of the light-emitting element formed using NCBA1BP (abbreviation) was 4.0% at a luminance of about 1000 cd / m2 2 The driving voltage and reliability at a luminance, in Embodiment 16, NCBA1BP was synthesized for a hole-transport layer in a manner similar to Embodiment 5; favorable values equivalent to those of the light-emitting element 8 formed using PCBBiNB in Embodiment 10 were obtained. When the driving voltage of the light-emitting element was 4.0 V, the luminance and current values were 1198 cd / m2 2 and 0.82 mA, respectively.

[0921] [Embodiment 17]

[0922] In Embodiment 17, the synthesis method of the carbazole derivative 4,4'-diphenyl-4"-(6,9-diphenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BPIII) represented by Structural Formula (422) will be described specifically.

[0923]

[0924] [Step 1: Synthesis of 3-bromo-6,9-diphenyl-9H-carbazole]

[0925] The following (S-1) shows a synthetic scheme of 3-bromo-6,9-diphenyl-9H-carbazole in Step 1.

[0926]

[0927] In a 300-mL Erlenmeyer flask, 4.8 g (15 mmol) of 3,9-diphenyl-9H-carbazole was added, and 250 mL of a mixed solvent (ethyl acetate:toluene = 4:1) was added to the solution. Then, the mixture was stirred for 30 minutes. Then, 2.7 g (15 mmol) of N-bromosuccinimide (abbreviation: NBS) was gradually added to the solution, and the solution was stirred for 48 hours.

[0928] After stirring, the mixture was washed with saturated sodium bicarbonate solution and saturated brine solution in this order. After washing, the water content of the obtained organic layer was removed by magnesium sulfate. Then, the mixture was suction-filtered to remove the magnesium sulfate, and a filtrate was obtained. The obtained filtrate was concentrated, and a small amount of ethanol was added to the obtained oily substance. Then, the mixture was treated with ultrasonic waves to precipitate solids. The precipitated solids were collected by suction filtration, and 5.4 g of white powdery solids were obtained at a yield of 90%.

[0929] [Step 2: Synthesis of 4,4'-diphenyl-4"-(6,9-diphenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BPIII)]

[0930] The following (S-2) shows a synthetic scheme of 4,4'-diphenyl-4"-(6,9-diphenyl-9H-carbazol-3-yl)triphenylamine in Step 2.

[0931]

[0932] In a 100-mL three-necked flask, 1.7 g (3.8 mmol) of N,N-bis(diphenyl-4-yl)aminophenyl-4-boronic acid, 1.5 g (3.8 mmol) of 3-bromo-6,9-diphenyl-9H-carbazole, 8.4 mg (0.038 mmol) of palladium (II) acetate, and 0.080 mg (0.26 mmol) of tri(o-tolyl)phosphine were added. Then, 10 mL of toluene, 2 mL of ethanol, and 10 mL of a 2M potassium carbonate solution were added to the mixture. After the mixture was degassed at low pressure, the atmosphere in the flask was replaced with nitrogen. The mixture was stirred at 100°C for 3 hours.

[0933] After stirring, toluene was added to the reaction mixture, and the mixture was heated at 50°C while stirring. After allowing the temperature of the suspension to drop to room temperature, the suspension was separated into an organic layer and an aqueous layer. The resulting organic layer was washed with a saturated sodium carbonate solution and a saturated brine solution in this order. After the washing, magnesium sulfate was added to the resulting organic layer to remove moisture. The mixture was suction-filtered to obtain a filtrate. The resulting filtrate was passed through celite (Wako Pure Chemical Industries, Ltd., Catalog No. 531-16855), Florisil (Wako Pure Chemical Industries, Ltd., Catalog No. 540-00135), and alumina by suction-filtration to obtain a filtrate. The resulting filtrate was concentrated and purified by silica gel column chromatography. The silica gel column chromatography was performed by using a toluene:hexane = 1:4 mixed solvent as a developing agent, and then using a toluene:hexane = 1:1 mixed solvent as another developing agent in this order. The resulting fraction was concentrated to obtain a solid, which was recrystallized from a chloroform and hexane mixed solvent to obtain 2.3 g of a white powdery solid at a yield of 87%.

[0934] The resulting 2.3 g of white solid was purified by sublimation. The purification by sublimation was performed at 320°C for 18 hours under a reduced pressure of 7.0 Pa at an argon gas flow rate of 4 mL / min. 1.8 g of a white solid was obtained at a yield of 78%.

[0935] The compound obtained in Step 2 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below. FIG. 61A and 61B show 1 H NMR spectra. It was found from the measurement results that the carbazole derivative PCBBi1BP III (abbreviation) of the present application represented by the above structural formula (422) was obtained.

[0936] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 7.22-7.77 (m, 36H), 8.38-8.42 (m, 2H).

[0937] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution (acetonitrile and 0.1% formic acid solution, mixing ratio of acetonitrile and formic acid solution, 80 / 20 vol / vol) was used as a solvent. Thus, a main peak (mode: ES+) of a molecular weight of 714.30 was detected, which confirmed that the target PCBBi1BP III (abbreviation) was obtained.

[0938] Further, various physical properties of PCBBi1BP III (abbreviation) were measured as follows.

[0939] Further, an absorption spectrum of PCBBi1BP III (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 348 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 352 nm. Further, an emission spectrum of PCBBi1BP III (abbreviation) was measured (measurement range: 390 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 397 nm (excitation wavelength: 358 nm); in the case of a thin film, the maximum emission wavelength was 439 nm (excitation wavelength: 369 nm).

[0940] The results of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBBi1BP III (abbreviation) was -5.46 eV. A Tauc plot of a thin film absorption spectrum showed that the absorption edge was 3.21 eV. Thus, the energy gap in the solid state was estimated to be 3.21 eV, which indicates that the LUMO level of PCBBi1BP III (abbreviation) was -2.25 eV.

[0941] The oxidation-reduction reaction characteristics of PCBBi1BP III (abbreviation) were examined by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description is omitted. According to calculation similar to Embodiment 1, the HOMO level of PCBBi1BP III (abbreviation) was found to be -4.1 [eV]. Further, the oxidation peak had a similar value even after 100 cycles. Thus, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[0942] Further, the glass transition temperature of PCBBi1BP III (abbreviation) was examined by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 138 °C. In this way, PCBBi1BP III (abbreviation) has a high glass transition temperature and favorable heat resistance. Further, there was no crystallization peak; thus, PCBBi1BP III (abbreviation) was found to be a substance that is difficult to crystallize.

[0943] Note that the efficiency of a light-emitting element formed using PCBBi1BP III (abbreviation) was about 1000 cd / m2 2the luminance and current values were 1070 cd / m2and 0.75 mA, respectively, and the light-emitting element showed 74% of the initial luminance after driving for 360 hours. 2 and 0.75 mA, respectively, and the light-emitting element showed 74% of the initial luminance after driving for 360 hours.

[0944] [Embodiment 18]

[0945] In Embodiment 18, a method for synthesizing the carbazole derivative of the present application represented by Structural Formula (423), 3,3'-dimethyl-4"-phenyl-4-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBA1BPIV), will be described specifically.

[0946]

[0947] [Step 1: Synthesis of 3,3'-dimethyl-4"-phenyl-triphenylamine]

[0948] The following (T-1) shows a flow of the synthesis of 3,3'-dimethyl-4"-phenyl- triphenylamine in Step 1.

[0949]

[0950] In a 100-mL three-necked flask, 5.8 g (25 mmol) of 4-bromobiphenyl, 4.9 g (25 mmol) of m,m'-dimethylaniline, 3.0 g (30 mmol) of sodium tert-butoxide, and 140 mg (0.25 mmol) of bis(dibenzylideneacetone) palladium (0) were placed, and the atmosphere in the flask was replaced with nitrogen. Then, 50 mL of xylene was added to the mixture. The mixture was degassed with stirring at a low pressure. After degassing, 1.0 mL (0.5 mmol) of tri-tert-butylphosphine (10% by weight of a hexane solution) was added thereto. The mixture was stirred at 130°C for 1.5 hours under a nitrogen atmosphere, and the reaction was completed.

[0951] After the reaction, 80 mL of toluene and 420 mL of hexane were added to the reaction mixture, and the suspension was sequentially passed through Florisil, silica gel, and celite. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove water. The suspension was sequentially passed through Florisil and celite to obtain a filtrate. The obtained filtrate was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 8.5 g of the target white powder at a yield of 97%.

[0952] The compound was analyzed by nuclear magnetic resonance (NMR)1 H NMR) measurement of the compound obtained from Step 1 above.

[0953] 1 H NMR (CDC13, 300 MHz): δ (ppm) = 2.28 (s, 6H), 6.85 (d, J = 6.9, 2H), 6.91-6.95 (m, 4H), 7.09-7.18 (m, 4H), 7.29 (t, J = 7.5, 1H), 7.38-7.48 (m, 4H), 7.56-7.59 (m, 2H).

[0954] [Step 2: Synthesis of 4-bromo-3,3'-dimethyl-4"-phenyl-triphenylamine]

[0955] The following (T-2) shows a synthesis scheme of 4-bromo-3,3'-dimethyl-4"-phenyl-triphenylamine in Step 2.

[0956]

[0957] In a 200-mL conical flask, 2.5 g (24 mmol) of 3,3'-dimethyl-4"-phenyl-triphenylamine was dissolved in 200 mL of ethyl acetate, and then 4.3 g (24 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 48 hours. After the completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove moisture. The mixture solution was filtered, and the obtained filtrate was concentrated and dried to obtain 9.1 g of the target caramel-like solid with a yield of 88%.

[0958] [Step 3: Synthesis of 3,3'-dimethyl-4"-phenyl-4-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBA1BPIV)]

[0959] The following (T-3) shows a synthesis scheme of 3,3'-dimethyl-4"-phenyl-4-(9-phenyl-9H-carbazol-3-yl)-triphenylamine in Step 3.

[0960]

[0961] In a 300-mL recovery flask, 1.7 g (4.0 mmol) of 4-bromo-3,3'-dimethyl-4"-phenyl- triphenylamine, 1.4 g (5.0 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, 5.0 mg (0.02 mmol) of palladium (II) acetate, and 6.0 mg (0.02 mmol) of tri(o-tolyl)phosphine were added, and 30 mL of toluene, 5 mL of ethanol, and 3.5 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 3 hours under a nitrogen atmosphere to allow the reaction.

[0962] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil and celite. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture, and the suspension was filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and hexane and acetone were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.0 g of the target white powder at a yield of 42%.

[0963] The Rf value of the target was 0.51 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10); and the Rf value of 4-bromo-3,3'-dimethyl-4"-phenyl- triphenylamine was 0.62.

[0964] The compound obtained by Step 3 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIGS. 62A to 62C showing 1 the H NMR spectrum. It was found from the measurement results that the carbazole derivative PCBA1BPIV (abbreviation) of the present application represented by the above structural formula (423) was obtained.

[0965] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 2.26 (s, 3H), 2.30 (s, 3H), 6.86 (d, J = 7.8, 1H), 6.99-7.59 (m, 25H), 8.09-8.13 (m, 2H).

[0966] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution of acetonitrile and a 0.1% formic acid solution (mixing ratio of acetonitrile to the formic acid solution, 80 / 20 vol / vol) was used as a solvent. Thus, a main peak of a molecular weight of 591.28 (mode: ES+) was detected, and it was confirmed that the target PCBA1BPIV (abbreviation) was obtained.

[0967] In addition, various physical properties of PCBA1BPIV (abbreviation) were measured as follows.

[0968] In addition, the absorption spectrum of PCBA1BPIV (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 325 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 329 nm. In addition, the emission spectrum of PCBA1BPIV (abbreviation) was measured (measurement range: 370 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 393 nm (excitation wavelength: 330 nm); in the case of a thin film, the maximum emission wavelength was 422 nm (excitation wavelength: 357 nm).

[0969] The result of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBA1BPIV (abbreviation) was -5.57 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption limit was 3.36 eV. Thus, it was estimated that the energy gap in the solid state was 3.36 eV, indicating that the LUMO level of PCBA1BPIV (abbreviation) was -2.21 eV.

[0970] In addition, the glass transition temperature of PCBA1BPIV (abbreviation) was detected by differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement result, the glass transition temperature was found to be 105°C. In this way, PCBA1BPIV (abbreviation) has a high glass transition temperature and favorable heat resistance. In addition, there was no crystallization peak; thus, it was found that PCBA1BPIV (abbreviation) is a substance that is difficult to crystallize.

[0971] Note that the efficiency of a light-emitting element formed using PCBA1BPIV (abbreviation) was about 1000 cd / m2 2The driving voltage and reliability at luminance, in Embodiment 18, PCBA1BPIV was synthesized for the hole-transporting layer in a manner similar to Embodiment 5; favorable values equivalent to those of the light-emitting element 8 were obtained, in Embodiment 10, the light-emitting element 8 was formed using PCBBiNB. When the driving voltage of the light-emitting element was 4.0 V, the luminance and current values were 924 cd / m 2 and 0.61 mA, respectively.

[0972] [Embodiment 19]

[0973] In Embodiment 19, a method for synthesizing the carbazole derivative of the present application represented by Structural Formula (345), 4,4'-bis(2-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBNBBβ), will be described specifically.

[0974]

[0975] [Step 1: Synthesis of 4,4'-bis(2-naphthyl)-triphenylamine]

[0976] The following (U-1) shows a synthetic flow of 4,4'-bis(2-naphthyl)-triphenylamine in Step 1.

[0977]

[0978] In a 300-mL three-necked flask, 6.0 g (15 mmol) of 4,4'-dibromo- triphenylamine, 6.2 g (36 mmol) of 2-naphthylboronic acid, 16 mg (0.1 mmol) of palladium (II) acetate, and 21 mg (0.1 mmol) of tri(o-tolyl)phosphine were placed, and 50 mL of toluene, 20 mL of ethanol, and 20 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 4.5 hours under a nitrogen atmosphere to allow the reaction.

[0979] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, and celite. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially filtered through Florisil, alumina, silica gel, and celite to obtain a filtrate. The obtained filtrate was concentrated, and hexane was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 5.6 g of the target white powder at a yield of 75%.

[0980] The Rf value of the target substance was 0.53, and the Rf value of 4,4'-dibromo- triphenylamine was 0.78 by thin layer chromatography (TLC) on silica gel (developing solvent, ethyl acetate:hexane = 1:10).

[0981] [Step 2: Synthesis of 4-bromo-4',4"-di(2-naphthyl)-triphenylamine]

[0982] The following (U-2) shows a synthesis scheme of 4-bromo-4',4"-di(2-naphthyl)- triphenylamine in Step 2.

[0983]

[0984] In a 500-mL conical flask, 4.0 g (8.0 mmol) of 4,4'-di(2-naphthyl)-triphenylamine was dissolved in 200 mL of toluene and 250 mL of ethyl acetate mixed solvent, and then 1.4 g (8 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. Then, the mixture was stirred at room temperature for 96 hours. After the completion of the reaction, the solution of the mixture was washed with water, and magnesium sulfate was added thereto to remove moisture. The suspension was filtered sequentially through Florisil and celite. The obtained filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The obtained fraction was concentrated, and acetone and hexane were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 3.4 g of the target white powder at a yield of 61%.

[0985] The compound obtained by Step 2 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below.

[0986] 1 1H NMR (CDC13, 300 MHz): δ (ppm) = 7.09 (d, J = 8.4, 2H), 7.24 (d, J = 7.8, 4H), 7.40 (d, J = 8.4, 2H), 7.47-7.51 (m, 4H), 7.66 (d, J = 8.1, 4H), 7.73-7.76 (m, 2H), 7.85-7.93 (m, 6H), 8.03 (s, 2H).

[0987] [Step 3: Synthesis of 4,4'-di(2-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBBβ)]

[0988] The following (U-3) shows a synthesis scheme of 4,4'-di(2-naphthyl)-4"-(9-phenyl-9H- carbazol-3-yl)-triphenylamine in Step 3.

[0989]

[0990] In a 50-mL three-necked flask, 1.0 g (1.7 mmol) of 4-bromo-4',4"-di(2-naphthyl)- triphenylamine, 0.6 g (2.0 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, 2.2 mg (1.0 μmol) of palladium (II) acetate, and 3.0 mg (10 μmol) of tri(o-tolyl)phosphine were added, and 20 mL of toluene, 3 mL of ethanol, and 2.0 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 14 hours under a nitrogen atmosphere to allow the reaction to proceed.

[0991] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil, silica gel, alumina, and celite. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and methanol, chloroform, acetone, and hexane were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.5 g of the target light yellow powder at a yield of 95%.

[0992] The Rf value of the target substance was 0.31 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10); the Rf value of 4-bromo-4',4"-di(2-naphthyl)- triphenylamine was 0.56.

[0993] The compound obtained from Step 3 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 63A and 63B showed 1 the H NMR spectrum. From the measurement results, the carbazole derivative PCBNBBβ (abbreviation) of the present application represented by the above structural formula (345) was found to be obtained.

[0994] 1 1H NMR (CDCI3, 300 MHz): δ (ppm) = 7.29-7.90 (m, 34H), 8.03 (s, 2H), 8.16 (d, J = 7.2, IH), 8.34 (d, J = 1.5, IH).

[0995] The molecular weight of the above compound was measured by a TOF-MS detector (Waters Micromass LCT Premier, manufactured by Waters). A mixed solution (acetonitrile / methanoic acid solution mixture, mixing ratio of acetonitrile and methanoic acid solution, 80 / 20 vol / vol) containing acetonitrile and 0.1% methanoic acid solution was used as a solvent. As a result, a main peak of molecular weight 739.32 (mode ES+) was detected, confirming that the target PCBNBBβ (abbreviation) was obtained.

[0996] Further, various physical properties of PCBNBBβ (abbreviation) were measured as follows.

[0997] Further, an absorption spectrum of PCBNBBβ (abbreviation) was measured (measurement range: 200 nm to 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 357 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 366 nm. Further, an emission spectrum of PCBNBBβ (abbreviation) was measured (measurement range: 390 nm to 550 nm). In the case of a toluene solution, the maximum emission wavelength was 415 nm (excitation wavelength: 360 nm); in the case of a thin film, the maximum emission wavelength was 449 nm (excitation wavelength: 376 nm).

[0998] The results of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBNBBβ (abbreviation) was -5.36 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption edge was 3.06 eV. Thus, the energy gap in the solid state was estimated to be 3.06 eV, which indicates that the LUMO level of PCBNBBβ (abbreviation) was -2.30 eV.

[0999] The oxidation-reduction reaction characteristics of PCBNBBβ (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description was omitted. According to calculation similar to Embodiment 1, the HOMO level of PCBNBBβ (abbreviation) was found to be -5.41 [eV]. Further, the oxidation peak had a similar value even after 100 cycles. Thus, it was found that the redox repetition between the oxidized state and the neutral state had favorable characteristics.

[1000] Further, the glass transition temperature of PCBNBBβ (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 129°C. In this way, PCBNBBβ (abbreviation) had a high glass transition temperature and favorable heat resistance. Further, there was no crystallization peak; thus, it was found that PCBNBBβ (abbreviation) was a substance that was difficult to crystallize.

[1001] Note that the efficiency of a light-emitting element formed using PCBNBBβ (abbreviation) was about 1000 cd / m2 2The driving voltage and reliability under luminance, PCBNBBβ was synthesized for the hole-transporting layer in Embodiment 19 in a similar manner to Embodiment 5; favorable values equivalent to those of the light-emitting element 8 formed using PCBBiNB in Embodiment 10 were obtained. When the driving voltage of this light-emitting element was 4.4 V, the luminance and current values were 1104 cd / m 2 and 0.74 mA, respectively, and the light-emitting element showed 75 % of the initial luminance after driving for 650 hours.

[1002] [Embodiment 20]

[1003] In Embodiment 20, the synthesis method of the carbazole derivative of the present application, 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)-4"-(9-phenylfluorene-9-yl)- triphenylamine (abbreviation: PCBBiFLP) represented by Structural Formula (424) will be described specifically. Note that the above compound is a carbazole derivative represented by General Formula (1), in which R 1 is hydrogen, R 2 is phenyl, 1 is 0, m is 1, n is 0, α 2 is 1,4-phenylene, α 4 is 1,4-phenylene, Ar 1 is biphenyl-4-yl, Ar 2 is fluorene-9-yl, and the 9th position of the fluorene-9-yl group is substituted with phenyl.

[1004]

[1005] [Step 1: Synthesis of 4-bromo-4'-phenyl-diphenylamine]

[1006] The following (V-l) shows a synthesis scheme of 4-bromo-4'-phenyl-diphenylamine in Step 1.

[1007]

[1008] In a 1000-mL conical flask, 37 g (150 mmol) of 4-phenyl-diphenylamine was dissolved in 400 mL of ethyl acetate, and then 27 g (150 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to the solution. After that, the mixture was stirred at room temperature for 24 hours.

[1009] After completion of the reaction, the mixture solution was washed with water, and magnesium sulfate was added thereto to remove water. The mixture solution was sequentially passed through Florisil, silica gel, alumina, and celite, and the obtained filtrate was concentrated, and toluene and hexane were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 4.0 g of the target white powder. In addition, the filtrate obtained at the recrystallization was purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The obtained fraction was concentrated, and methanol was added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 4.5 g of the target white powder. Thus, a total of 8.5 g of the target white powder was obtained at a yield of 73%.

[1010] [Step 2: Synthesis of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)-diphenylamine]

[1011] The following (V-2) shows a synthesis scheme of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)-diphenylamine in Step 2.

[1012]

[1013] In a 200-mL three-necked flask, 16 g (50 mmol) of 4-bromo-4'-phenyl-diphenylamine, 16 g (55 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, 110 mg (0.4 mmol) of palladium (II) acetate, and 150 mg (0.4 mmol) of tri(o-tolyl)phosphine were added, and 70 mL of toluene, 5 mL of ethanol, and 23 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, the mixture was stirred at 90°C for 7.5 hours under a nitrogen atmosphere to allow the reaction.

[1014] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially passed through Florisil, silica gel, and celite. The obtained filtrate was washed with water. Then, magnesium sulfate was added to remove water. The suspension was sequentially passed through Florisil, alumina, silica gel, and celite to obtain a filtrate. The obtained filtrate was concentrated, and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The obtained fraction was concentrated, and chloroform and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 10 g of the target light yellow powder at a yield of 41%.

[1015] [Step 3: Synthesis of 9-(4-bromophenyl)-9-phenylfluorene]

[1016] The following (V-3) shows a synthesis scheme of 9-(4-bromophenyl)-9-phenylfluorene in Step 3.

[1017]

[1018] In a 100-mL three-necked flask, 1.2 g (50 mmol) of magnesium was added, and the mixture was stirred for 30 minutes to activate the magnesium under low pressure. After the flask was cooled to room temperature and made into a nitrogen atmosphere, a few drops of dibromoethane were added to confirm the formation of foam and heat generation. After 12 g (50 mmol) of 2-bromobiphenyl dissolved in 10 mL of diethyl ether was slowly added to the mixture, the mixture was stirred and refluxed for 2.5 hours to prepare a Grignard reagent.

[1019] In a 500-mL three-necked flask, 10 g (40 mmol) of 4-bromobenzophenone and 100 mL of diethyl ether were added. After the previously synthesized Grignard reagent was slowly added to the mixture, the mixture was stirred and refluxed for 9 hours.

[1020] After the reaction, the mixture was filtered to obtain a filtrate. The obtained filtrate was dissolved in 150 mL of ethyl acetate, 1N-hydrochloric acid solution was added thereto, and the mixture was stirred for 2 hours. The organic layer of the solution was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was filtered, and the obtained filtrate was concentrated to obtain a candied substance.

[1021] In a 500-mL recovery flask, the candied substance, 50 mL of glacial acetic acid, and 1.0 mL of hydrochloric acid were added, and the mixture was stirred at 130°C for 1.5 hours under a nitrogen atmosphere to react. After the reaction, the reaction mixture solution was filtered to obtain a filtrate. The obtained filtrate was washed with water, a sodium hydroxide aqueous solution, water, and methanol in this order to obtain 11 g of a target white powder at a yield of 69%.

[1022] [Step 4: Synthesis of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)-4"-(9-phenylfluorene-9-yl)- triphenylamine (abbreviation: PCBBiFLP)]

[1023] The following (V-4) shows a synthesis scheme of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)-4"-(9-phenylfluorene-9-yl)-triphenylamine in Step 4.

[1024]

[1025] In a 100-mL three-necked flask, 1.2 g (3.0 mmol) of 9-(4-bromophenyl)-9- phenylfluorene, 1.5 g (3.0 mmol) of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)- diphenylamine, 0.4 mg (4.0 mmol) of sodium tert-butoxide, and 17 mg (0.03 mmol) of bis(dibenzylideneacetone) palladium(0) were charged, and the atmosphere in the flask was replaced with nitrogen. Then, 20 mL of anhydrous xylene was added to the mixture. The mixture was degassed under low pressure with stirring. After degassing, 0.2 mL (0.1 mmol) of tri(tert-butyl)phosphine (10% (wt) hexane solution) was added thereto. The mixture was stirred at 130°C for 5.5 hours under a nitrogen atmosphere, and the reaction was completed.

[1026] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially filtered through Florisil and celite. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 1.8 g of the target white powder at a yield of 76%.

[1027] The Rf value of the target substance was 0.35, the Rf value of 9-(4-bromophenyl)-9- phenylfluorene was 0.65, and the Rf value of 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)- diphenylamine was 0.19 by silica gel thin layer chromatography (TLC) (developing solvent, ethyl acetate:hexane = 1:10).

[1028] The compound obtained by Step 4 above was measured by nuclear magnetic resonance method (1H NMR). 1 The measurement results are described below, FIG. 64A and 64B showed 1 H NMR spectra. From the measurement results, the carbazole derivative of the present application, PCBBiFLP (abbreviation) represented by the above structural formula (424) was obtained.

[1029] 1 H NMR (CDC13, 300 MHz): δ (ppm) = 7.02 (d, J = 8.7, 2H), 7.12 (d, J = 8.7, 2H), 7.17-7.64 (m, 36H), 7.77 (d, J = 6.9, 2H).

[1030] In addition, various physical properties of PCBBiFLP (abbreviation) were measured as follows.

[1031] Further, the absorption spectrum of PCBBiFLP (abbreviation) was measured (measurement range: 200 nm - 800 nm). In the case of a toluene solution, an absorption peak on the long wavelength side was observed at about 337 nm; in the case of a thin film, an absorption peak on the long wavelength side was observed at about 339 nm. Further, the emission spectrum of PCBBiFLP (abbreviation) was measured (measurement range: 390 nm - 550 nm). In the case of a toluene solution, the maximum emission wavelength was 395 nm (excitation wavelength: 343 nm); in the case of a thin film, the maximum emission wavelength was 425 nm (excitation wavelength: 361 nm).

[1032] The results of measurement of a thin film with a photoelectric spectrophotometer (AC-2, manufactured by Riken Keiki Co., Ltd.) under normal pressure indicated that the HOMO level of PCBBiFLP (abbreviation) was -5.53 eV. The Tauc plot of the thin film absorption spectrum showed that the absorption edge was 3.28 eV. Therefore, the energy gap in the solid state was estimated to be 3.28 eV, which indicates that the LUMO level of PCBBiFLP (abbreviation) was -2.25 eV.

[1033] The oxidation-reduction reaction characteristics of PCBBiFLP (abbreviation) were detected by cyclic voltammetry (CV) measurement. Since the measurement method was similar to that of Embodiment 1, the description was omitted. According to calculations similar to those of Embodiment 1, the HOMO level of PCBBiFLP (abbreviation) was found to be -5.42 [eV]. Further, the oxidation peak had a similar value even after 100 cycles. Therefore, the redox repetition between the oxidized state and the neutral state was found to have favorable characteristics.

[1034] Further, the glass transition temperature of PCBBiFLP (abbreviation) was detected with differential scanning calorimetry (Pyris 1 DSC, manufactured by Perkin Elmer Co., Ltd.). According to the measurement results, the glass transition temperature was found to be 156°C. In this way, PCBBiFLP (abbreviation) had a high glass transition temperature and favorable heat resistance. Further, there was no crystallization peak; therefore, PCBBiFLP (abbreviation) was found to be a substance that is difficult to crystallize.

[1035] Note that the efficiency of a light-emitting element formed using PCBBiFLP (abbreviation) was about 1000 cd / m 2 The driving voltage and reliability at high luminance in Embodiment 20 were synthesized in a manner similar to Embodiment 5 using PCBBiFLP (abbreviation) for the hole-transport layer; favorable values equivalent to those of the light-emitting element 8 formed using PCBBiNB in Embodiment 10 were obtained. When the driving voltage of the light-emitting element was 4.4 V, the luminance and current values were 1104 cd / m 2and 0.65 mA, the light emitting element showed 74% of the initial luminance after driving for 360 hours.

[1036] Note that the efficiency of the light emitting element formed using PCBBiFLP (abbreviation) was about 1000 cd / m 2 The driving voltage and reliability at a luminance of about 1000 cd / m 2 and 0.65 mA, the light emitting element showed 74% of the initial luminance after driving for 360 hours.

[1037] [Embodiment 21]

[1038] In Embodiment 21, a method for synthesizing the carbazole derivative 4-(l-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBANB) represented by Structural Formula (343) according to the present application will be specifically described, which is different from Embodiment 8.

[1039]

[1040] [Step 1: Synthesis of 1-(4-bromophenyl)-naphthalene]

[1041] The following (W-1) shows a synthesis scheme of 1-(4-bromophenyl)-naphthalene in Step 1.

[1042]

[1043] In a 500-mL three-necked flask, 46 g (160 mmol) of 4-bromoiodobenzene, 24 g (140 mmol) of 1-naphthaleneboronic acid, 45 mg (0.2 mmol) of palladium (II) acetate, and 60 mg (0.2 mmol) of tri(o-tolyl)phosphine were placed, and 100 mL of toluene, 20 mL of ethanol, and 11 mL of a potassium carbonate solution (2 mol / L) were added to the mixture. The mixture was degassed under stirring at low pressure. After degassing, the mixture was stirred at 90°C for 4 hours under a nitrogen atmosphere to carry out the reaction.

[1044] After the reaction, 500 mL of toluene was added to the reaction mixture, and the suspension was sequentially passed through Florisil and celite filters. The resulting filtrate was washed with water. Then, magnesium sulfate was added to remove moisture. The suspension was sequentially passed through Florisil and celite filters to obtain a filtrate. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, hexane). The resulting fraction was concentrated to obtain 25 g of the target colorless transparent liquid at a yield of 62%.

[1045] The Rf value of the target by thin layer chromatography (TLC) on silica gel (developing solvent, hexane) was 0.38; and the Rf value of 4-bromoiodobenzene was 0.57.

[1046] [Step 2: Synthesis of 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)- triphenylamine (abbreviation: PCBANB)]

[1047] The following (W-2) shows a flow of the synthesis of 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)-triphenylamine in Step 2.

[1048]

[1049] In a 100-mL three-necked flask, 2.8 g (10 mmol) of 1-(4-bromophenyl)-naphthalene, 4.1 g (10 mmol) of 4-(9-phenyl-9H-carbazol-3-yl)-diphenylamine, 1.2 g (12 mmol) of sodium tert-butoxide, and 11 mg (0.02 mmol) of bis(dibenzylideneacetone) palladium(0) were added, and the atmosphere in the flask was replaced with nitrogen. Then, 30 mL of anhydrous xylene was added to the mixture. The mixture was degassed with stirring at low pressure. After degassing, 0.1 mL (0.06 mmol) of tri(tert-butyl)phosphine (10% by weight hexane solution) was added thereto. The mixture was stirred at 110°C for 6 hours under a nitrogen atmosphere to allow the reaction.

[1050] After the reaction, 150 mL of toluene was added to the reaction mixture, and the suspension was sequentially passed through Florisil, silica gel, and celite filters. The resulting filtrate was concentrated and purified by silica gel column chromatography (developing solvent, toluene:hexane = 1:4). The resulting fraction was concentrated, and acetone and methanol were added thereto. The mixture was treated with ultrasonic waves, and then recrystallized to obtain 5.2 g of the target white powder at a yield of 85%.

[1051] Note that Florisil and Celite described in each of the above synthetic methods of the embodiments of the present application mean the use of Florisil (Wako Pure Chemical Industries, Ltd., Catalog No. 540-00135) and Celite (Wako Pure Chemical Industries, Ltd., Catalog No. 531-16855), respectively, unless otherwise specified.

[1052] This application is based on Japanese Patent Application Serial No. 2007-312509 and Japanese Patent Application Serial No. 2008-129917, filed on December 3, 2007 and May 16, 2008, respectively, with the Japan Patent Office, the entire contents of which are incorporated herein by reference.

[1053] Reference Symbol Explanation

[1054] 101:substrate, 102: first electrode, 103: EL layer, 104: second electrode, 111: first layer (hole-injection layer), 112: second layer (hole-transport layer), 113: third layer (light-emitting layer), 114: fourth layer (electron-transport layer), 115: fifth layer (electron-injection layer), 301: first electrode, 302: second electrode, 303: first EL layer, 304: second EL layer, 305: charge-generation layer, 401: excitation-circuit portion (source excitation circuit), 402: pixel portion, 404: sealing substrate, 405: sealing agent, 407: space, 408: lead wire, 409: FPC (flexible printed circuit), 410: element substrate, 411: switching TFT, 412: current control TFT, 413: first electrode, 414: insulator, 416: EL layer, 417: second electrode, 418: light-emitting element, 423: n-channel TFT, 424: p-channel TFT, 501: substrate, 502: first electrode, 503: second electrode, 504: EL layer, 505: insulating layer, 506: spacer layer, 611: housing, 612: support base, 613: display portion, 614: speaker portion, 615: video input terminal, 621: main body, 622: housing, 623: display portion, 624: keyboard, 625: external connection port, 626: pointing device, 631: main body, 632: housing, 633: display portion, 634: audio input portion, 635: audio output portion, 636: operation key, 637: external connection port, 638: antenna, 641: main body, 642: display portion, 643: housing, 644: external connection port, 645: remote control receiving portion, 646: image receiving portion, 647: battery, 648: audio input portion, 649: operation key, 650: eyepiece portion, 701: housing, 702: liquid crystal layer, 703: backlight, 704: housing, 705: excitation IC, 706: terminal, 801: housing, 802: light source, 901: illuminating device, 902: television, 1501: substrate, 1502: first electrode, 1503: EL layer, 1504: second electrode, 1511: first layer, 1512: second layer, 1513: third layer, 1514: fourth layer, 1515: fifth layer.

Claims

1. A compound represented by the general formula (9): ###0001### wherein: 1, m, and n are each independently 0 or 1. wherein, a 1 , a 2 , a 3 and a 4 each represent an arylene group having less than or equal to 13 carbon atoms, Ar 1 represents formula (3-6): Ar 2 represents an aryl group having less than or equal to 13 carbon atoms, X 3 represents a halogen group, 2. A compound represented by the general formula (11): ###0002### wherein: 1 and n are each independently 0 or 1. R 81 -R 85 , R 88 and R 89 each represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group and a diphenyl group, and R 86 and R 87 are mutually linked to form a fluorene ring.

3. A light-emitting element comprising: an anode, an EL layer over the anode, the EL layer comprising a hole-injection layer in contact with the anode, a hole-transport layer over the hole-injection layer, and a light-emitting layer over the hole-transport layer, and a cathode over the EL layer, wherein: the hole-transport layer comprises a compound represented by the formula (1): ###0003### wherein: 1, m, and n are each 0. wherein, a 1 , a 3 and a 4 each represent an arylene group having less than or equal to 13 carbon atoms, R 1 represents any of a hydrogen atom, an alkyl group having 1-6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group, R 2 represents any of an alkyl group having 1-6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group, the hole-injection layer comprises a substance having a hole-transport property and a substance having an accepting property. Ar 1 represents formula (3-6): R 81 -R 85 , R 88 and R 89 each represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group and a diphenyl group, and R 86 and R 87 are mutually linked to form a fluorene ring.

5. The light-emitting element according to claim 3, wherein: the anode comprises any of aluminum, silver, and an alloy containing aluminum.

6. The light-emitting element according to claim 3, wherein: the light-emitting layer comprises a light-emitting substance and a plurality of substances.

7. A light-emitting element comprising: an anode, an EL layer over the anode, the EL layer comprising a hole-injection layer in contact with the anode, a hole-transport layer over the hole-injection layer, and a light-emitting layer over the hole-transport layer, and a cathode over the EL layer, wherein: the hole-injection layer and the hole-transport layer each comprise a compound represented by the formula (1): ###0004### wherein: 1, m, and n are each 0. the hole-injection layer comprises the compound and a substance having an accepting property.

9. The light-emitting element according to claim 7, wherein: the anode comprises any of aluminum, silver, and an alloy containing aluminum.

10. The light-emitting element according to claim 7, wherein: the light-emitting layer comprises a light-emitting substance and a plurality of substances. Ar 2 denotes unsubstituted phenyl, Ar 1 is represented by formula (3-6): α 1 -α 4 each is represented by formula (2-1): R 1 , R 11 , R 12 , R 14 , R 15 , R 81 - R 85 , R 88 and R 89 each denote any of hydrogen and an alkyl group having 1 to 6 carbon atoms, R 2 is phenyl, R 86 and R 87 are mutually connected to form a fluorene ring, and 11. A light-emitting element comprising: an anode, a first layer over the anode, a light-emitting layer over the first layer, a second layer over the light-emitting layer, and a cathode over the light-emitting layer, wherein: the first layer comprises a compound represented by the formula (1): ###0005### wherein: 1, m, and n are each 0.

4. The light-emitting element according to claim 3, wherein the first layer comprises a substance having a hole-transport property and a substance having an accepting property.

13. The light-emitting element according to claim 11, wherein: the anode comprises any of aluminum, silver, and an alloy containing aluminum. wherein, 14. The light-emitting element according to claim 11, wherein: the light-emitting layer comprises a light-emitting substance and a plurality of substances.

15. A compound represented by the formula (1): ###0006### wherein: 1 is 0, m is 1, and n is 0. wherein, 16. A light-emitting element comprising: a pair of electrodes, and a layer comprising the compound according to claim 15.

17. A compound represented by the formula (1): ###0007### wherein: 1 and n are each 0, and m is 1.

18. A compound represented by the formula (1): ###0008### wherein: 1 is 0, m is 1, and n is 0.

19. A compound represented by the formula (1): ###0009### wherein: 1 is 0, m is 1, and n is 0.

20. An electronic device comprising: the compound according to claim 18 or claim 19.

21. An electronic device comprising: the compound according to claim 18 or claim 19, and a pair of electrodes. ​ Ar 2 denotes unsubstituted phenyl, Ar 1 is represented by formula (3-6): α 1 -α 4 each is represented by formula (2-1): R 1 , R 11 , R 12 , R 14 , R 15 , R 81 - R 85 , R 88 and R 89 each denote any of hydrogen and an alkyl group having 1-6 carbon atoms, R 2 is phenyl, R 86 and R 87 are mutually connected to form a fluorene ring, and ​ 8. The light-emitting element according to claim 7, wherein ​ ​ wherein, ​ ​ wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ Ar 2 denotes unsubstituted phenyl, Ar 1 is represented by formula (3-6): α 1 -α 4 each is represented by formula (2-1): R 1 , R 11 , R 12 , R 14 , R 15 , R 81 - R 85 , R 88 and R 89 each denote any of hydrogen and an alkyl group having 1-6 carbon atoms, R 2 is phenyl, R 86 and R 87 are mutually connected to form a fluorene ring, and ​ 12. The light-emitting element according to claim 11, wherein ​ ​ wherein ​ ​ wherein ​ ​ ​ Ar 1 represented by formula (3-1), and Ar 2 represents an aryl group having 6-13 carbon atoms forming a ring: α 1 , α 3 and α 4 each represent an unsubstituted phenylene group, and α 2 is represented by formula (2-4), R 1 represents hydrogen, R 2 represents an unsubstituted phenyl group, R 21 -R 24 , R 26 -R 29 , R 51 , R 52 , R 54 -R 56 each represents any of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a phenyl group, and ​ ​ ​ ​ ​ ​ Ar 1 is represented by formula (3-6): Ar 2 denotes unsubstituted phenyl, α 1 -α 4 each is represented by formula (2-1): R 1 , R 81 -R 85 , R 88 and R 89 each denote any of hydrogen and an alkyl group having 1 to 6 carbon atoms, R 2 is phenyl, R 11 , R 12 , R 14 , and R 15 each represent any of hydrogen, phenyl, and biphenyl, R 86 and R 87 each is alkyl having 1-6 carbon atoms, ​ ​ ​ ​ Ar 1 is represented by formula (1-1): Ar 2 represents an unsubstituted phenyl group, α 1 -α 4 each is represented by formula (2-1): R 1 represents hydrogen, R 2 represents any of an alkyl group having 1-6 carbon atoms, a substituted or unsubstituted phenyl group, and a substituted or unsubstituted biphenyl group, R 11 , R 12 , R 14 , and R 15 each represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group, R 111 - R 115 each represent any of hydrogen, an alkyl group having 1 to 6 carbon atoms, a phenyl group, and a biphenyl group, R 116 and R 117 are connected to each other to form a fluorene ring, R 118 and R 119 each represents any of hydrogen, alkyl having 1 to 6 carbon atoms, phenyl and diphenyl, and l, m and n each are 0 or 1. ​ ​ Ar 1 is represented by formula (1-1): Ar 2 denotes unsubstituted phenyl, α 1 -α 4 each is represented by formula (2-1): R 1 represents hydrogen, R 2 represents a substituted or unsubstituted phenyl group, R 11 , R 12 , R 14 and R 15 each represent hydrogen, R 111 - R 115 each represent hydrogen, R 116 and R 117 are each connected to each other to form a fluorene ring, R 118 and R 119 each represent hydrogen, and l, m and n are each 0 or 1. ​ ​ ​ ​ ​

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