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

Abstract

A new substance that can increase the lifespan and emission efficiency of a light-emitting element is provided. A carbazole compound having a structure represented by the general formula (G1) is provided. It should be noted that substituents that can deepen the HOMO level and shallow the LUMO level of the compound are used as each substituent (specifically, R<supgt;1< / supgt;, R<supgt;2< / supgt;, Ar<supgt;3< / supgt; and α<supgt;3< / supgt;) in the general formula (G1), and the bonds of the substituents in the compound are replaced by hydrogen. In addition, substituents that can widen the bandgap (Bg) and increase the T1 level of the compound are used as each substituent (specifically, R<supgt;1< / supgt;, R<supgt;2< / supgt;, Ar<supgt;3< / supgt; and α<supgt;3< / supgt;) in the general formula (G1), and the bonds of the substituents in the compound are replaced by hydrogen.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a carbazole compound and a light-emitting element using the carbazole compound. The present invention also relates to a light-emitting device, an electronic device, and a lighting device each including the light-emitting element.

[0003] 2. Description of the Related Art

[0004] In recent years, active research and development have been conducted on light-emitting elements utilizing electroluminescence (EL). In the basic structure of such a light-emitting element, a layer containing a light-emitting substance is inserted between a pair of electrodes. By applying a voltage to the element, light emission can be obtained from the light-emitting substance.

[0005] Such light-emitting elements are of the self-luminous type, and thus their advantages over liquid crystal displays are high pixel visibility and the absence of a backlight, etc. Therefore, such a light-emitting element may be suitable as a flat panel display element. At the same time, such a light-emitting element has the advantages that it can be made into a thin and light element and has an extremely fast response speed.

[0006] Moreover, since such a light-emitting element can be made into a film form, surface light emission can be easily obtained. Therefore, a large-area element utilizing surface-emitted light can be formed. This is a characteristic that is difficult to obtain with point light sources represented by incandescent lamps and LEDs or line light sources represented by fluorescent lamps. Therefore, the light-emitting element is particularly effective as a surface light source in applications such as lighting.

[0007] Light-emitting elements utilizing electroluminescence properties can be broadly classified according to whether an organic compound or an inorganic compound is used as the light-emitting substance. In the case of using an organic compound as the light-emitting substance, by applying a voltage to the light-emitting element, electrons and holes can be injected from a pair of electrodes into the layer containing the light-emitting organic compound, thereby generating a current. Then, these carriers (i.e., electrons and holes) recombine, thereby exciting the light-emitting organic compound. The light-emitting organic compound returns from the excited state to the ground state, thereby emitting light. It should be noted that the excited state of the organic compound can be a singlet excited state or a triplet excited state, and the light emitted from the singlet excited state is called fluorescence, and the light emitted from the triplet excited state is called phosphorescence.

[0008] When improving the element characteristics of such a light-emitting element, there are many problems related to substances. To solve these problems, improvements in the element structure and research and development of substances have been carried out. For example, Patent Document 1 discloses a light-emitting element in which a compound having an anthracene skeleton and a carbazole skeleton is used as a light-emitting material. However, it cannot be considered that the light-emitting element has sufficiently high reliability.

[0009] In addition, Patent Document 2 discloses a light-emitting element in which a compound used has an anthracene skeleton and a carbazole skeleton each containing a substituted or unsubstituted phenyl group, and has excellent carrier transport properties. The light-emitting element has a low driving voltage and high reliability.

[0010] [References]

[0011] [Patent Document 1] PCT International Publication WO 2005 / 113531

[0012] [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-167175 Summary of the Invention

[0013] When the compound described in Patent Document 2 is used in an element containing a phosphorescent substance, since the T1 energy level (triplet excitation energy) of the anthracene skeleton in the compound is insufficient, the excitation energy of the phosphorescent substance may be quenched, making it difficult to obtain high emission efficiency. In addition, when the compound is used in an element containing a blue fluorescent substance, although high emission efficiency can be obtained, even higher efficiency is still required.

[0014] In view of the above problems, an object of one embodiment of the present invention is to provide a new substance that can extend the life of a light-emitting element and improve emission efficiency. Specifically, an object of one embodiment of the present invention is to provide a new carbazole compound that can be used in a light-emitting element.

[0015] One embodiment of the present invention is a carbazole compound represented by the general formula (G1). [1]

[0017]

[0018] It should be noted that in the general formula (G1), R 1 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzo[9,10]phenanthryl group (triphenylenyl), and a substituent represented by the general formula (G1-1). In the general formula (G1), R 2 represents hydrogen, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and any one of a substituent represented by the general formula (G1-2). In the general formula (G1), α 3 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. In the general formula (G1), Ar 3 represents any one of a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. [2]

[0020]

[0021] It should be noted that in general formula (G1-1), Ar 1 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In general formula (G1-1), α 1 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. In general formula (G1-1), n represents 0 or 1. [3]

[0023]

[0024] It should be noted that in general formula (G1-2), Ar 2 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In general formula (G1-2), α 2 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.

[0025] In addition, R in general formula (G1) 1 can be any one of the structures represented by structural formulas (S-1) to (S-5) and general formula (G1-1). [4]

[0027]

[0028] It should be noted that in general formula (G1-1), Ar 1 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In general formula (G1-1), α 1 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. In general formula (G1-1), n represents 0 or 1.

[0029] In addition, R in general formula (G1) 2 can be any one of the structures represented by structural formulas (S-11) to (S-16) and general formula (G1-2). [5]

[0031]

[0032] It should be noted that in the general formula (G1-2), Ar 2 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In the general formula (G1-2), α 2 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.

[0033] 3 In addition, α in the general formula (G1), α 1 in the general formula (G1-1), and α 2 in the general formula (G1-2) can independently be any one of the structures represented by the structural formulas (α-1) to (α-7). [6]

[0035]

[0036] In addition, Ar 1 in the general formula (G1-1) and Ar 2 in the general formula (G1-2) can independently be any one of the structures represented by the structural formulas (Ar-1) to (Ar-10). [7]

[0038]

[0039] Furthermore, Ar 3 in the general formula (G1) can be any one of the structures represented by the structural formulas (Ar-11) to (Ar-15). [8]

[0041]

[0042] One embodiment of the present invention is a light-emitting element using the carbazole compound.

[0043] One embodiment of the present invention is a light-emitting device including the above-described light-emitting element.

[0044] One embodiment of the present invention is a lighting device including the above-described light-emitting device.

[0045] One embodiment of the present invention is an electronic device including the above-described light-emitting device.

[0046] ​It should be noted that the light-emitting devices in this specification include, in their classification, image display devices, light-emitting devices, and light sources. Moreover, the light-emitting devices include, in their classification, 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 connected to a panel, a module in which a printed circuit board is assembled at the end of the TAB tape or 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.

[0047] According to an embodiment of the present invention, a new carbazole compound can be provided. The carbazole compound has a wide band gap and can be used as a light-emitting element material. In addition, the carbazole compound has a high T1 energy level and can be used as a light-emitting element material. In addition, the carbazole compound has high carrier transport properties and can be used as a light-emitting element material.

[0048] According to an embodiment of the present invention, a light-emitting element with high emission efficiency and long life can be provided. Moreover, according to an embodiment of the present invention, highly reliable light-emitting devices, lighting devices, and electronic devices that respectively use the light-emitting element can be provided. Brief Description of the Drawings

[0049] Figure 1A and 1B Each shows a light-emitting element according to an embodiment of the present invention.

[0050] Figure 2A and 2B Each shows a light-emitting element according to an embodiment of the present invention.

[0051] Figure 3A and 3B Shows a light-emitting device according to an embodiment of the present invention.

[0052] Figure 4A and 4B Shows a light-emitting device according to an embodiment of the present invention.

[0053] Figures 5A to 5E Each shows an electronic device according to an embodiment of the present invention.

[0054] Figure 6 Shows a lighting device according to an embodiment of the present invention.

[0055] Figure 7A and 7B Is the NMR spectrum of PCPN.

[0056] Figure 8A and 8B Is the NMR spectrum of 3-(4-bromophenyl)-9-phenyl-9H-carbazole.

[0057] Figure 9 is the MS spectrum of 3-(4-bromophenyl)-9-phenyl-9H-carbazole.

[0058] Figure 10A and 10B show the absorption and emission spectra of PCPN in a toluene solution of PCPN.

[0059] Figure 11A and 11B show the absorption and emission spectra of the PCPN film.

[0060] Figure 12A and 12B is the NMR spectrum of PCPPn.

[0061] Figure 13A and 13B show the absorption and emission spectra of PCPPn in a toluene solution of PCPPn.

[0062] Figure 14A and 14B show the absorption and emission spectra of the PCPPn film.

[0063] Figure 15A and 15B is the NMR spectrum of PCzPTp.

[0064] Figure 16A and 16B show the absorption and emission spectra of PCzPTp in a toluene solution of PCzPTp.

[0065] Figure 17A and 17B is the NMR spectrum of mPCPPn.

[0066] Figure 18A and 18B show the absorption and emission spectra of mPCPPn in a toluene solution of mPCPPn.

[0067] Figure 19A and 19B show the absorption and emission spectra of the mPCPPn film.

[0068] Figure 20A and 20B is the NMR spectrum of mPCzPTp.

[0069] Figure 21A and 21B show the absorption and emission spectra of mPCzPTp in a toluene solution of mPCzPTp.

[0070] Figure 22A and 22B Show the absorption spectrum and emission spectrum of the mPCzPTp film.

[0071] Figure 23A and 23B is the NMR spectrum of NCPN.

[0072] Figure 24A and 24B Show the absorption spectrum and emission spectrum of NCPN in the toluene solution of NCPN.

[0073] Figure 25A and 25B Show the absorption spectrum and emission spectrum of the NCPN film.

[0074] Figure 26A and 26B is the NMR spectrum of NP2PC.

[0075] Figure 27A and 27B Show the absorption spectrum and emission spectrum of NP2PC in the toluene solution of NP2PC.

[0076] Figure 28A and 28B Show the absorption spectrum and emission spectrum of the NP2PC film.

[0077] Figure 29 Show the light-emitting elements of the examples.

[0078] Figure 30 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 9.

[0079] Figure 31 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 9.

[0080] Figure 32 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 9.

[0081] Figure 33 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 9.

[0082] Figure 34 Show the results of the reliability test conducted on the light-emitting element and the comparative light-emitting element in Example 9.

[0083] Figure 35 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 10.

[0084] Figure 36 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 10.

[0085] Figure 37 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 10.

[0086] Figure 38 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 10.

[0087] Figure 39 Show the results of the reliability tests conducted on the light-emitting element and the comparative light-emitting element in Example 10.

[0088] Figure 40 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 11.

[0089] Figure 41 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 11.

[0090] Figure 42 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 11.

[0091] Figure 43 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 11.

[0092] Figure 44 Show the results of the reliability tests conducted on the light-emitting element and the comparative light-emitting element in Example 11.

[0093] Figure 45 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 12.

[0094] Figure 46 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 12.

[0095] Figure 47 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 12.

[0096] Figure 48 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 12.

[0097] Figure 49 Show the results of the reliability tests conducted on the light-emitting element and the comparative light-emitting element in Example 12.

[0098] Figure 50 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 13.

[0099] Figure 51Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 13.

[0100] Figure 52 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 13.

[0101] Figure 53 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 13.

[0102] Figure 54 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 14.

[0103] Figure 55 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 14.

[0104] Figure 56 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 14.

[0105] Figure 57 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 14.

[0106] Figure 58 Show the results of the reliability tests conducted on the light-emitting element and the comparative light-emitting element in Example 14.

[0107] Figure 59 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 15.

[0108] Figure 60 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 15.

[0109] Figure 61 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 15.

[0110] Figure 62 Show the structure of the light-emitting element in the example.

[0111] Figure 63 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 16.

[0112] Figure 64 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 16.

[0113] Figure 65 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 16.

[0114] Figure 66Show the emission spectrum of the light-emitting element in Example 17.

[0115] Figure 67 Show the voltage-luminance characteristics of the light-emitting element in Example 17.

[0116] Figure 68 Show the luminance-current efficiency characteristics of the light-emitting element in Example 17.

[0117] Figure 69 Show the emission spectrum of the light-emitting element in Example 18.

[0118] Figure 70 Show the voltage-luminance characteristics of the light-emitting element in Example 18.

[0119] Figure 71 Show the luminance-current efficiency characteristics of the light-emitting element in Example 18.

[0120] Figure 72 Show the luminance-power efficiency characteristics of the light-emitting element in Example 18.

[0121] Figure 73 Show the emission spectrum of the light-emitting element in Example 19.

[0122] Figure 74 Show the voltage-luminance characteristics of the light-emitting element in Example 19.

[0123] Figure 75 Show the luminance-current efficiency characteristics of the light-emitting element in Example 19.

[0124] Figure 76 Show the luminance-power efficiency characteristics of the light-emitting element in Example 19.

[0125] Figure 77 Show the results of the reliability test on the light-emitting element in Example 19.

[0126] Figure 78 Show the emission spectra of the light-emitting element and the comparative light-emitting element in Example 20.

[0127] Figure 79 Show the voltage-luminance characteristics of the light-emitting element and the comparative light-emitting element in Example 20.

[0128] Figure 80 Show the luminance-current efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 20.

[0129] Figure 81 Show the luminance-power efficiency characteristics of the light-emitting element and the comparative light-emitting element in Example 20.

[0130] Figure 82A and82B is the NMR spectrum of Cl-PPn2.

[0131] Figure 83A and 83B is the NMR spectrum of Pn2BPPC.

[0132] Figure 84A and 84B show the absorption spectrum and emission spectrum of Pn2BPPC in a toluene solution of Pn2BPPC.

[0133] Figure 85A and 85B show the absorption spectrum and emission spectrum of a Pn2BPPC film.

[0134] Figure 86A and 86B is the NMR spectrum of PCPCl2.

[0135] Figure 87A and 87B is the NMR spectrum of Pn2PPC.

[0136] Figure 88A and 88B show the absorption spectrum and emission spectrum of Pn2PPC in a toluene solution of Pn2PPC.

[0137] Figure 89A and 89B show the absorption spectrum and emission spectrum of a Pn2PPC film. DETAILED DESCRIPTION OF THE INVENTION

[0138] The embodiments and examples of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the following description, and those skilled in the art can easily understand that various changes and improvements can be made without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited by the description of the embodiments and examples.

[0139] (Embodiment 1)

[0140] In this embodiment, a carbazole compound according to an embodiment of the present invention will be described.

[0141] A carbazole compound according to an embodiment of the present invention is a carbazole compound represented by the general formula (G1). [9]

[0143]

[0144] It should be noted that in the general formula (G1), R 1Represents any one of an alkyl group having 1 - 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, a substituted or unsubstituted benzo[9,10]phenanthryl group (triphenylenyl), and a substituent represented by the general formula (G1-1). In the general formula (G1), R 2 Represents any one of hydrogen, an alkyl group having 1 - 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituent represented by the general formula (G1-2). In the general formula (G1), α 3 Represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. In the general formula (G1), Ar 3 Represents any one of a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group.

[10]

[0146]

[0147] It should be noted that in the general formula (G1-1), Ar 1 Represents any one of an alkyl group having 1 - 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In the general formula (G1-1), α 1 Represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. In the general formula (G1-1), n represents 0 or 1.

[11]

[0149]

[0150] It should be noted that in the general formula (G1-2), Ar 2 Represents any one of an alkyl group having 1 - 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In the general formula (G1-2), α 2 Represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.

[0151] It should be noted that substituents that can make the HOMO energy level of the compound deep (large absolute value) are used as each substituent in the general formula (G1) (specifically R 1 , R 2 , Ar 3 and α 3), the bond of the substituent in the compound is replaced by hydrogen. Specifically, preferably, for a compound in which the bond of the substituent in the general formula (G1) is replaced by hydrogen, its HOMO energy level is less than or equal to -5.5 eV. Accordingly, the carbazole compound represented by the general formula (G1) in the present embodiment has a deep HOMO energy level.

[0152] In addition, a substituent that can widen the band gap (Bg) and increase the T1 energy level of the compound is used as each substituent in the general formula (G1) (specifically, R 1 , R 2 , Ar 3 and α 3 ), the bond of the substituent in the compound is replaced by hydrogen. Specifically, preferably, for a compound in which the bond of the substituent in the general formula (G1) is replaced by hydrogen, its band gap is greater than or equal to 2.7 eV (greater than or equal to the blue fluorescence energy, preferably greater than or equal to 3.0 eV), and its T1 energy level is greater than or equal to 1.8 eV (greater than or equal to the red phosphorescence energy). Accordingly, the carbazole compound represented by the general formula (G1) in the present embodiment has a wide band gap and a high T1 energy level. Therefore, when the carbazole compound of the present embodiment is used as the host material of the light-emitting layer or the layer adjacent to the light-emitting layer, the light-emitting element may be able to emit light more effectively without taking away the excitation energy from the light-emitting substance with high excitation energy. In addition, when the carbazole compound of the present embodiment is used as the light-emitting substance, short-wavelength (blue-violet to blue) light can be obtained.

[0153] Even if the material has a deep HOMO energy level, as long as the material has a wide band gap, it can maintain a shallow LUMO energy level. Therefore, when the carbazole compound of the present embodiment is used in the hole transport layer of the light-emitting element, it may be able to prevent electrons from passing through the adjacent light-emitting layer and may be able to effectively recombine the carriers in the light-emitting layer.

[0154] For the above reasons, a substituent that can make the LUMO energy level of the compound shallow (small absolute value) is used as each substituent in the general formula (G1) (specifically, R 1 , R 2 , Ar 3 and α 3 ), the bond of the substituent in the compound is replaced by hydrogen. Specifically, preferably, for a compound in which the bond of the substituent in the general formula (G1) is replaced by hydrogen, its LUMO energy level is greater than or equal to -2.5 eV.

[0155] When R 1 , R 2 , α 3 and Ar 3In the case of further having substituents, considering the HOMO energy level, LUMO energy level and band gap, the substituents are independently preferably any one of an alkyl group having 1-12 carbon atoms, a phenyl group, a biphenyl group, a naphthyl group, a phenanthryl group, and a benzo[9,10]phenanthryl group.

[0156] Specifically, Ar 3 (Ar 2 ) is part of the substituent connected to the 3-position (6-position) of the carbazole skeleton, and is preferably a fused ring such as a naphthyl group, a phenanthryl group, and a benzo[9,10]phenanthryl group, because such a fused ring has excellent carrier transport properties. Specifically, Ar 3 (Ar 2 ) is preferably a naphthyl group or a phenanthryl group. In addition, in terms of high molecular weight and improved thermophysical properties, Ar 3 (Ar 2 ) is preferably a phenanthryl group or a benzo[9,10]phenanthryl group. It should be noted that naphthalene is a bicyclic fused ring, so it has a wide band gap and a high T1 energy level. Although phenanthrene or benzo[9,10]phenanthrene is a fused ring having three or more rings, compared with anthracene having a tricyclic fused ring or tetracene having a tetracyclic fused ring, phenanthrene or benzo[9,10]phenanthrene has a wider band gap and a higher T1 energy level, because phenanthrene or benzo[9,10]phenanthrene does not have a polyacene structure (the fused ring is not linear), but has a helicene structure (the fused ring is twisted) combined with each other in its structure.

[0157] In addition, the arylene group represented by α 3 (α 2 ) is preferably located between the carbazole skeleton and Ar 3 (Ar 2 ). In this case, it is difficult to conjugate and extend from the carbazole skeleton to Ar 3 (Ar 2 ). Specifically, the arylene group is preferably bonded at the meta-position or ortho-position (for example, the 1-position and 3-position of a phenylene group, and the 1-position and 2-position of a phenylene group). In this case, the conjugate extension may be more inhibited, and the band gap may increase. When the arylene group is bonded at the para-position, excellent thermophysical properties (high Tg) and excellent carrier transport properties may be obtained. In addition, for example, using a benzene skeleton or a biphenyl skeleton, such that α 3 (α 2 ) is an arylene group having a small conjugation, thereby preventing the conjugate extension of α 3 (α 2 ) itself.

[0158] With respect to each substituent Ar 1 , Ar 2 and Ar 3The attached substituent is preferably an aryl group. In this case, the carbazole compound is soluble in solvents. Specifically, due to its excellent solubility, methyl or tert-butyl is preferred. Substituent Ar in general formula (G1) 1 , Ar 2 and Ar 3 When having substituents such as alkyl or aryl groups, the structure of the carbazole compound in the present embodiment is more steric. As a result, crystallization may not be easy, and concentration quenching caused by molecular stacking can be suppressed.

[0159] In addition, when substituent R 2 in general formula (G1) is a group different from hydrogen, substituent R 2 and substituent α 3 -Ar 3 are preferably the same. In this case, synthesis is easier. Substituent R 2 and substituent α 3 -Ar 3 are preferably the same. In this case, the molecular weight increases, improving the thermophysical properties. It should be noted that substituent R 2 is preferably hydrogen. In this case, compared with when substituent R 2 is a group different from hydrogen, the band gap is wider and the T1 energy level is higher.

[0160] Specific examples using the above substituents will be described below.

[0161] Structural formulas (S-1) to (S-5) and general formula (G1-1) etc. are shown as specific examples of the substituent represented by R 1 in general formula (G1).

[12]

[0163]

[0164] It should be noted that in general formula (G1-1), Ar 1 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In general formula (G1-1), α 1 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group. In general formula (G1-1), n represents 0 or 1.

[0165] Structural formulas (S-11) to (S-16) and general formula (G1-2) etc. are shown as specific examples of the substituent represented by R 2 in general formula (G1).

[13]

[0167]

[0168] It should be noted that in the general formula (G1-2), Ar 2 represents any one of an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group. In the general formula (G1-2), α 2 represents a substituted or unsubstituted phenylene group or a substituted or unsubstituted biphenyldiyl group.

[0169] Structural formulas (α-1) to (α-7) etc. are shown as specific examples of the substituents represented by α in the general formula (G1) 3 , α in the general formula (G1-1) 1 or α in the general formula (G1-2) 2 .

[14]

[0171]

[0172] Structural formulas (Ar-1) to (Ar-10) etc. are shown as specific examples of the substituents represented by Ar in the general formula (G1-1) 1 or Ar in the general formula (G1-2) 2 .

[15]

[0174]

[0175] Structural formulas (Ar-11) to (Ar-15) etc. are shown as specific examples of the substituents represented by Ar in the general formula (G1) 3 .

[16]

[0177]

[0178] Carbazole compounds represented by structural formulas (100)-(131), (140)-(151), (160)-(183), and (190)-(197) are shown as specific examples of the carbazole compounds represented by the general formula (G1). However, the present invention is not limited to these compounds.

[17]

[0180]

[18]

[0182]

[19]

[0184]

[20]

[0186]

[21]

[0188]

[22]

[0190]

[23]

[0192]

[24]

[0194]

[25]

[0196]

[26]

[0198]

[27]

[0200]

[28]

[0202]

[29]

[0204]

[30]

[0206]

[0207] Various reactions can be applied to the synthesis method of the carbazole compound of the present embodiment. For example, the carbazole compound of the present embodiment can be synthesized by any one of the synthesis reactions described in Synthesis Methods 1-3. It should be noted that in the synthesis schemes described below, the numbers related to the general formula (G1) are not specifically explained (i.e., R 1 , R 2 , α 3 and Ar 3 ).

[0208] <Synthesis Method 1>

[0209] First, as shown in Reaction Scheme (A-1), the carbazole compound (a3) is synthesized by the coupling of the halogenated carbazole compound (a1) and the arylboron compound (a2).

[31]

[0211]

[0212] It should be noted that X1 represents a halogen. X 1 Preferably represents highly reactive bromine, more preferably iodine. B 1 represents boric acid or dialkoxyboron

[0213] It should be noted that various reaction conditions can be used for the coupling reaction in Reaction Scheme (A-1). As one example, a synthetic method using a metal catalyst in the presence of a base can be employed

[0214] Examples of using the Suzuki-Miyaura reaction in Reaction Scheme (A-1) will be described below. A palladium catalyst can be used as the metal catalyst, and a mixture of a palladium complex and its ligand can be used as the palladium catalyst. Palladium(II) acetate, tetrakis(triphenylphosphine)palladium(0), and bis(triphenylphosphine)palladium(II) dichloride are given as examples of the palladium complex. Tri(o-tolyl)phosphine, triphenylphosphine, and tricyclohexylphosphine are given as examples of the ligand. In addition, organic bases such as sodium tert-butoxide and inorganic bases such as potassium carbonate are given as examples of substances that can be used as the base. The reaction is preferably carried out in a solution. Examples of solvents that can be used are as follows: 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, etc. However, the catalysts, ligands, bases, and solvents that can be used are not limited to these. In addition, in Reaction Scheme (A-1), an arylaluminum compound, an arylzirconium compound, an arylzinc compound, or an aryltin compound, etc. can be used instead of the arylboron compound (a2). Additionally, the reaction is preferably carried out under an inert atmosphere such as nitrogen, argon, etc

[0215] In Reaction Scheme (A-1), the halogen group X of compound (a1) is shown 1 reacting with the boron compound group B of compound (a2) 1 However, even coupling compound (a1) as the boron compound with compound (a2) as the halide (with the reaction groups X 1 and B 1 interchanged with each other) can also give the carbazole compound (a3)

[0216] Next, as shown in Reaction Scheme (A-2), the halogenated carbazole compound (a4) is synthesized by halogenating the carbazole compound (a3)

[32]

[0218]

[0219] It should be noted that X 2 represents a halogen. X 2Preferably, it represents bromine with high reactivity, and more preferably iodine.

[0220] A variety of reaction conditions can be used for the halogenation reaction in Reaction Scheme (A-2). For example, a reaction using a halogenating agent in the presence of a polar solvent can be employed. N-bromosuccinimide (abbreviation: NBS), N-iodosuccinimide (abbreviation: NIS), bromine, iodine, potassium iodide, etc. can be used as the halogenating agent. It is preferable to use a bromide as the halogenating agent, in which case the cost of synthesis is low. Additionally, when using an iodide as the halogenating reagent, the iodine-substituted part in the resulting compound (i.e., the iodide) has high reactivity. Therefore, it is preferable to conduct a reaction using the resulting compound (i.e., the iodide) as the raw material, in which case the reaction proceeds more easily.

[0221] Next, as shown in Reaction Scheme (A-3), a carbazolyl boron compound is synthesized by reacting the compound activated by reacting the halogenated carbazole compound (a4) with a metal catalyst with a boron compound.

[33]

[0223]

[0224] It should be noted that X 2 represents a halogen. X 2 Preferably, it represents bromine with high reactivity, and more preferably iodine. Additionally, B 2 represents boric acid or dialkoxyboron.

[0225] In Reaction Scheme (A-3), as an example of activating the halogenated carbazole compound (a4), a lithiation reaction with an alkyllithium reagent can be used. Examples of the alkyllithium reagent include n-butyllithium, tert-butyllithium, and methyllithium. An acid such as hydrochloric acid can be used. An ether such as diethyl ether or tetrahydrofuran (THF) can be used as the dehydrating solvent. Examples of the boron compound that can be used include trimethyl borate and triethyl borate.

[0226] Next, as shown in Reaction Scheme (A-4), a halogenated carbazole compound (a7) is obtained by coupling the carbazolyl boron compound (a5) and the diaryl dihalide compound (a6).

[34]

[0228]

[0229] It should be noted that X 3 and X 4 each represent a halogen. X 3 and X 4 each preferably represent bromine with high reactivity, and more preferably iodine. In the case of a specific reaction of B 2 and X 3 it is preferable to use the same as X 4Compared to a halogen with higher reactivity as X 3 It should be noted that among the halogens, bromine has higher reactivity than chlorine, and iodine has higher reactivity than bromine. B 2 represents boric acid or dialkoxyboron.

[0230] A variety of reaction conditions can be used for the coupling reaction in Reaction Scheme (A-4). As an example, a synthetic method using a metal catalyst in the presence of a base can be employed. Specifically, the coupling reaction can be carried out in a manner similar to Reaction Scheme (A-1); thus, the above description can be referred to.

[0231] In Reaction Scheme (A-4), the halogen group X of compound (a6) is shown 3 reacting with the boron compound group B of compound (a5) 2 However, even when compound (a5) as a boron compound and compound (a6) as a halide (the reaction groups X 3 and B 2 are mutually replaced) are coupled, the carbazole compound (a7) can be obtained. It should be noted that in this case, a halogen group with higher reactivity than the halogen group X 4 needs to be used as the halogen group X 3 to prevent the reaction between compounds (a6).

[0232] Next, as shown in Reaction Scheme (A-5), the carbazole compound represented by the general formula (G1) can be obtained by coupling the halogenated carbazole compound (a7) and the arylboron compound (a8).

[35]

[0234]

[0235] It should be noted that X 4 represents a halogen. X 4 Preferably represents bromine with high reactivity, and more preferably iodine. B 3 represents boric acid or dialkoxyboron.

[0236] A variety of reaction conditions can be used for the coupling reaction in Reaction Scheme (A-5). As an example, a synthetic method using a metal catalyst in the presence of a base can be employed. Specifically, the coupling reaction can be carried out in a manner similar to Reaction Scheme (A-1); thus, the above description can be referred to.

[0237] In Reaction Scheme (A-5), the halogen group X of compound (a7) is shown 4 reacting with the boron compound group B of compound (a8) 3Case of mutual reaction. However, even when coupling compound (a7) as a boron compound with compound (a8) as a halide (where the reactive groups X 4 and B 3 are mutually replaced), a carbazole compound represented by the general formula (G1) can be obtained.

[0238] In addition, in Reaction Schemes (A-1) to (A-5), it is shown that the substituent -R 2 binds to the 3-position of the carbazole skeleton, and then the substituent -α 3 -Ar 3 binds to the 6-position of the carbazole skeleton. However, the present invention is not limited to the above reactions. Even when the substituent -α 3 -Ar 3 is bound and then the substituent -R 2 is bound, a carbazole compound represented by the general formula (G1) can be synthesized.

[0239] It should be noted that the substituent -R 2 and the substituent -α 3 -Ar 3 preferably have the same skeleton. In this case, the reaction in which the substituent R 2 and the substituent α 3 -Ar 3 bind to the 3-position and 6-position of the carbazole skeleton simultaneously, respectively, is likely to proceed.

[0240] The synthesis method 2 described below is a synthesis method of the carbazole compound of the present embodiment, which is different from the synthesis method 1.

[0241] <Synthesis Method 2>

[0242] As shown in Reaction Scheme (B-1), a carbazole compound represented by the general formula (G1) can be synthesized by the coupling of a halogenated carbazole compound (a4) and an arylboron compound (a9).

[36]

[0244]

[0245] It should be noted that X 2 represents a halogen. X 2 preferably represents bromine with high reactivity, and more preferably iodine. B 4 represents boric acid or dialkoxyboron.

[0246] A variety of reaction conditions can be used for the coupling reaction in Reaction Scheme (B-1). As an example, a synthesis method using a metal catalyst in the presence of a base can be adopted. Specifically, the coupling reaction can be carried out in a manner similar to Reaction Scheme (A-1); therefore, the above description can be referred to.

[0247] In reaction scheme (B-1), the halogen group X of compound (a4) is shown 2 reacting with the boron compound group B of compound (a9). 4 However, even when compound (a4) as a boron compound and compound (a9) as a halide (with the reaction groups X 2 and B 4 exchanged with each other) are coupled, a carbazole compound represented by the general formula (G1) can be obtained.

[0248] In addition, in reaction scheme (B-1), the example where the substituent -R 2 binds to the 3-position of the carbazole skeleton and then the substituent -α 3 -Ar 3 binds to the 6-position of the carbazole skeleton is shown. However, the present invention is not limited to the above reaction. Even when the substituent -α 3 -Ar 3 is bound and then the substituent -R 2 is bound, a carbazole compound represented by the general formula (G1) can be synthesized.

[0249] It should be noted that the substituent -R 2 and the substituent -α 3 -Ar 3 preferably have the same skeleton, and in this case, the reaction in which the substituent -R 2 and the substituent -α 3 -Ar 3 bind to the 3-position and 6-position of the carbazole skeleton simultaneously respectively is easy to carry out.

[0250] Synthesis method 3 described below is a synthesis method of the carbazole compound of the present embodiment, which is different from synthesis method 1 and synthesis method 2.

[0251] <Synthesis method 3>

[0252] As shown in reaction scheme (C-1), a carbazole compound represented by the general formula (G1) can be synthesized by coupling a carbazole compound (a10) and an aryl halide compound (a11).

[37]

[0254]

[0255] It should be noted that X 5 represents a halogen. X 5 preferably represents bromine with high reactivity, and more preferably iodine.

[0256] In the coupling reaction of the aryl compound having a halogen group with the 9-position of carbazole shown in reaction scheme (C-1), various reaction conditions can be used for the coupling reaction. As one example, a synthesis method using a metal catalyst in the presence of a base can be used.

[0257] The following describes the case where the Buchwald-Hartwig reaction is carried out in the reaction scheme (C-1). A palladium catalyst can be used as a metal catalyst, and a mixture of a palladium complex and its ligand can be used as a palladium catalyst. Examples of palladium catalysts such as di(dibenzylideneacetone)palladium(0) and palladium acetate(II) are given. Examples of ligands such as tri-tert-butylphosphine, tri-n-hexylphosphine, tricyclohexylphosphine, 1,1-bis(diphenylphosphino)ferrocene (abbreviation: DPPF) are given. Organic bases such as sodium tert-butoxide and inorganic bases such as potassium carbonate are given as substances that can be used as bases. In addition, the reaction is preferably carried out in a solution. Toluene, xylene and benzene are given as examples of solvents that can be used. However, the catalysts, ligands, bases and solvents that can be used are not limited thereto. It should be noted that the reaction is preferably carried out under an inert atmosphere such as nitrogen and argon.

[0258] The following describes the situation of carrying out Ullmann reaction in reaction scheme (C-1). A copper catalyst can be used as a metal catalyst, and cuprous iodide (I) and copper acetate (II) are given as examples of copper catalysts. Inorganic bases such as potassium carbonate are given as examples of substances that can be used as bases. The above reaction is preferably carried out in a solution, and 1,3-dimethyl-3,4,5,6-tetrahydro-2 (1H)-pyrimidone (abbreviation: DMPU), toluene, xylene and benzene are given as examples of solvents that can be used. But usable catalysts, ligands, alkalis and solvents are not limited thereto. In addition, the reaction is preferably carried out under an inert atmosphere such as nitrogen, argon.

[0259] It should be noted that it is preferable to use a high boiling point solvent such as DMPU or xylene, because the target substance can be obtained in a shorter time and at a higher yield by the Ullmann reaction when the reaction temperature is higher than or equal to 100° C. Specifically, since the reaction temperature is more preferably higher than or equal to 150° C., DMPU is more preferable.

[0260] It should be noted that the substitution of -R can be carried out in a similar manner to reaction schemes (A-1) to (A-5) or reaction scheme (B-1). 2 and substituent-α 3 -Ar 3 The reaction of bonding at the 3-position and the 6-position of the carbazole skeleton. Therefore, the above description can be referred to in detail.

[0261] In the above-described manner, the carbazole compound of the present embodiment can be synthesized.

[0262] The carbazole compound of the present embodiment has a deep HOMO energy level (i.e., a large absolute value), and thus has excellent properties of injecting holes into the light-emitting layer. In addition, the carbazole compound of the present embodiment is electrochemically stable against oxidation. For these reasons, the carbazole compound of the present embodiment can preferably be used as a material for the hole transport layer of a light-emitting element. In addition, a composite material formed by mixing the carbazole compound (electron donor) of the present embodiment and an electron acceptor can be used as the hole injection layer of the light-emitting element. It should be noted that the electron acceptor and the electron donor can at least provide and accept electrons under the action of an electric field.

[0263] In addition, the carbazole compound of the present embodiment has a shallow LUMO energy level (i.e., a small absolute value); therefore, using the carbazole compound as the material of the hole transport layer of the light-emitting element can block the transmission of electrons to the anode. In this way, the efficiency of the light-emitting element using the carbazole compound of the present embodiment is improved.

[0264] In addition, the carbazole compound of the present embodiment has a wide band gap; thus, even when the carbazole compound is used for the hole transport layer adjacent to the light-emitting layer, the energy transfer from the light-emitting layer can be suppressed. In this way, the lifetime and efficiency of the light-emitting element using the carbazole compound of the present embodiment are improved.

[0265] In addition, the carbazole compound of the present embodiment emits fluorescence, and thus can emit short-wavelength light. In this way, by using the carbazole compound of the present embodiment as the light-emitting material, light in the blue-violet to blue range can be obtained.

[0266] In addition, the carbazole compound of the present embodiment is also preferably used as the host material of the light-emitting layer in the light-emitting element. In other words, when a light-emitting substance (hereinafter also referred to as "dopant") having a narrower band gap than the carbazole compound of the present embodiment is added to the layer formed of the carbazole compound, light can be emitted from the dopant. At this time, even when a fluorescent dopant that emits light of a shorter wavelength such as blue light is used, light can be effectively emitted from the dopant because the carbazole compound of the present embodiment has a wide band gap. In other words, the carbazole compound of the present embodiment can be used as the host material of a compound that emits fluorescence in the visible light range. In addition, when the dopant is a phosphorescent compound, a substance having a T1 energy level higher than that of the dopant is preferably used as the host material. The carbazole compound of the present embodiment has a high T1 energy level, and thus can be used as the host material of a compound that emits phosphorescence in the visible light range, and the wavelength of the phosphorescence is at least longer than that of green light.

[0267] In addition, the carbazole compound of the present embodiment has weak light absorption in the visible light range (about 380 nm to 750 nm), and when a film is formed using the carbazole compound, the transmittance of visible light is high. Thus, the carbazole compound of the present embodiment is not easily absorbent of emission energy even when used in a light-emitting element, which results in a high external quantum yield of the light-emitting element.

[0268] The present embodiment can be implemented in combination with any other embodiment according to appropriate circumstances.

[0269] (Embodiment 2)

[0270] In the present embodiment, as an embodiment of the present invention, the light-emitting element using the carbazole compound described in Embodiment 1 will be described with reference to the attached Figure 1A and 1B drawings.

[0271] In the light-emitting element of the present embodiment, an EL layer including at least a light-emitting layer is inserted between a pair of electrodes. The EL layer may have a plurality of layers in addition to the light-emitting layer. The plurality of layers are stacked in a combination of layers formed of materials having high carrier injection properties and high carrier transport properties, so that a light-emitting region is formed away from the electrodes, that is, carriers recombine in a portion away from the electrodes. For example, the plurality of layers may include a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, and the like.

[0272] In Figure 1A the light-emitting element of the present embodiment shown in the figure, an EL layer 102 is provided between a pair of electrodes, that is, a first electrode 101 and a second electrode 103. In addition, the EL layer 102 includes a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115. It should be noted that in the light-emitting element described in the present embodiment, the function of the first electrode 101 provided on the substrate 100 is to serve as an anode, and the function of the second electrode 103 is to serve as a cathode.

[0273] The substrate 100 serves as a support for the light-emitting element. For example, glass, quartz, plastic, etc. can be used as the substrate 100. A flexible substrate can be used. A flexible substrate is a substrate that can be bent (flexible). Examples of flexible substrates include plastic substrates made of polycarbonate, polyacrylate, polyethersulfone, etc. A film (constituted of polypropylene, polyester, vinyl materials, polyvinyl fluoride, vinyl chloride, etc.), or an inorganic film formed by evaporation, etc. can be used. It should be noted that other materials can be used as long as they function as a support during the production process of the light-emitting element.

[0274] For the first electrode 101, it is preferable to use a metal, alloy, conductive compound, or a mixture thereof having a high work function (specifically, a work function of 4.0 eV or more). Specific examples include indium tin oxide (ITO: indium tin oxide), indium tin oxide containing silicon or silicon oxide, indium zinc oxide (IZO: indium zinc oxide), indium oxide containing tungsten oxide and zinc oxide (IWZO), etc. The film of the conductive metal oxide is usually formed by a sputtering method, but may also be formed by a sol-gel method or other methods. For example, indium zinc oxide (IZO) can be formed by a sputtering method using a target in which 1 wt% - 20 wt% of zinc oxide is added to indium oxide. In addition, indium oxide containing tungsten oxide and zinc oxide (IWZO) can be formed by a sputtering method using a target in which 0.5 wt% - 5 wt% of tungsten oxide is added to indium oxide and 0.1 wt% - 1 wt% of zinc oxide is added to indium oxide. In addition, gold, platinum, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, metal nitride materials (such as titanium nitride), etc. are shown.

[0275] It should be noted that in the EL layer 102, when a composite material is used to form the layer in contact with the first electrode 101, the composite material is formed using an organic compound and an electron acceptor (acceptor) described below, and any material among various metals, alloys, conductive compounds, their mixtures, etc. can be used to form the first electrode 101 regardless of the work function. For example, aluminum, silver, or an aluminum alloy (such as Al-Si) can be used.

[0276] In the EL layer 102 formed on the first electrode 101, at least one of the hole injection layer 111, the hole transport layer 112, and the light-emitting layer 113 contains a carbazole compound according to an embodiment of the present invention. Known substances can be used for a part of the EL layer 102, and a low molecular compound or a high molecular compound can be used. It should be noted that the substance for forming the EL layer 102 not only has a structure formed of an organic compound, but also has a structure partially containing an inorganic compound.

[0277] The hole injection layer 111 is a layer containing a substance having a high hole injection property. As a substance having a high hole injection property, for example, metal oxides such as molybdenum oxide, titanium oxide, vanadium oxide, rhenium oxide, ruthenium oxide, chromium oxide, zirconium oxide, hafnium oxide, tantalum oxide, silver oxide, tungsten oxide, and manganese oxide can be used. Compounds based on phthalocyanine such as phthalocyanine (abbreviation: H2Pc) or copper phthalocyanine (II) (abbreviation: CuPc) can also be used.

[0278] Other examples of substances that can be used are aromatic amine compounds belonging to low-molecular organic compounds: such as 4,4',4”-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4”-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), and the like.

[0279] In addition, any high-molecular compound (for example, oligomer, dendrimer, or polymer) can also be used. Examples of high-molecular compounds are as follows: poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), or poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), and the like. A high-molecular compound added with an acid can also be used, for example, poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) or polyaniline / poly(styrenesulfonic acid) (PAni / PSS).

[0280] A composite material formed by mixing an organic compound with an electron acceptor (acceptor) can be used for the hole injection layer 111. This composite material has excellent hole injection properties and hole transport properties because the electron acceptor can generate holes in the organic compound. In this case, the organic compound is preferably a material excellent in transporting the generated holes (a substance having a high hole transport property).

[0281] As the organic compound for the composite material, various compounds can be used, for example, any one of aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and high-molecular compounds (for example, oligomers, dendrimers, and polymers). The organic compound for the composite material preferably has a high hole transport property. Specifically, it is preferable to use an organic compound having a hole mobility of 10 or more-6 cm 2 a substance of / Vs. It should be noted that any other substance can also be used as long as the hole transport property of the substance is greater than its electron transport property. Specific examples of the organic compounds that can be used in the composite material are as follows.

[0282] The carbazole compound of one embodiment of the present invention is an organic compound with high hole transport property, so it can be preferably used as a composite material. In addition, the following substances can be used as the organic compounds that can be used in the composite material, for example: aromatic amine compounds such as TDATA, MTDATA, DPAB, DNTPD, DPA3B, PCzPCA1, PCzPCA2, PCzPCN1, 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or a-NPD), and N,N′-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), and 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP); and carbazole compounds such as 4,4'-bis(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthryl)phenyl-]9H-carbazole (abbreviation: CzPA), 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), and 1,4-bis[4-(N-carbazolyl)phenyl-2,3,5,6-tetraphenylbenzene.

[0283] Any one of the following aryl hydrocarbon compounds can be used: 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-bis(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 9,10-bis[2-(1-naphthyl)phenyl]-2-tert-butylanthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, and 2,3,6,7-tetramethyl-9,10-bis(1-naphthyl)anthracene, etc.

[0284] Any one of the following aromatic compounds can be used: 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthracene, 10,10'-diphenyl-9,9'-bianthracene, 10,10'-bis(2-phenylphenyl)-9,9'-bianthracene, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthracene, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, pentacene, coronene, 4,4'-bis(2,2-diphenylethenyl)biphenyl (abbreviation: DPVBi), 9,10-bis[4-(2,2-diphenylethenyl)phenyl]anthracene (abbreviation: DPVPA), etc.

[0285] Organic compounds such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ) and chloranil, and transition metal oxides are given as examples of electron acceptors. Oxides of metals in Groups 4-8 of the periodic table can also be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferably used because they have high electron-accepting properties. Among them, molybdenum oxide is particularly preferred because it is stable in air, has low hygroscopicity, and is easy to handle.

[0286] It should be noted that the above electron acceptors and the above polymer compounds such as PVK, PVTPA, PTPDMA, or Poly-TPD can be used to form a composite material, and the composite material can be used for the hole injection layer 111.

[0287] The hole transport layer 112 is a layer containing a substance having high hole transport properties. The carbazole compound of one embodiment of the present invention is an organic compound having high hole transport properties, and thus can preferably be used as a material for the hole transport layer 112.

[0288] The light-emitting layer 113 is a layer containing a light-emitting substance. As the light-emitting substance, for example, a fluorescent compound that emits fluorescence or a phosphorescent compound that emits phosphorescence can be used.

[0289] The carbazole compound of one embodiment of the present invention is a material that exhibits blue-violet to blue fluorescence, and thus can also be used as a light-emitting substance.

[0290] In addition, blue light-emitting materials, green light-emitting materials, yellow light-emitting materials, and red light-emitting materials are given as fluorescent compounds that can be used in the light-emitting layer 113. Examples of blue light-emitting materials are as follows: N,N′-bis[4-(9H-carbazol-9-yl)phenyl]-N,N′-diphenyl-4,4′-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4′-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(10-phenyl-9-anthryl)-4′-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), etc. Examples of green light-emitting materials are as follows: N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N′,N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1′-biphenyl-2-yl)-2-anthryl]-N,N′,N′-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), N-[9,10-bis(1,1′-biphenyl-2-yl)]-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), etc. Rubrene, 5,12-bis(1,1′-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), etc. are given as examples of yellow light-emitting materials. N,N,N′,N′-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N′,N′-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), etc. are given as examples of red light-emitting materials.

[0291] Blue light-emitting materials, green light-emitting materials, yellow light-emitting materials, orange light-emitting materials, and red light-emitting materials are given as fluorescent compounds that can be used in the light-emitting layer 703. Examples of blue light-emitting materials are as follows: bis[2-(4′,6′-difluorophenyl)pyridine-N,C 2′ iridium(III) tetra(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4′,6′-difluorophenyl)pyridine-N,C 2′ iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3′,5′-bis(trifluoromethyl)phenyl]pyridine-N,C 2'Iridium(III) complex (abbreviation: Ir(CF3ppy)2(pic)) and bis[2-(4′,6′-difluorophenyl)pyridine-N,C acetylacetonato]iridium(III) 2' (abbreviation: FIr(acac)), etc. Examples of materials for green light-emitting materials are as follows: Tris(2-phenylpyridine-N,C 2' ) iridium(III) (abbreviation: Ir(ppy)3), bis(2-phenylpyridine-N,C acetylacetonato)iridium(III) 2' ) (abbreviation: Ir(ppy)2(acac)), bis(1,2-diphenyl-1H-benzimidazole)acetylacetonatoiridium(III) (abbreviation: Ir(pbi)2(acac)), bis(benzo[h]quinoline)acetylacetonatoiridium(III) (abbreviation: Ir(bzq)2(acac)), etc. Examples of materials for yellow light emission include: Bis(2,4-diphenyl-1,3-oxazole-N,C acetylacetonato)iridium(III) 2' ) (abbreviation: Ir(dpo)2(acac)), bis[2-(4′-(pentafluorophenyl)phenyl)pyridine]acetylacetonatoiridium(III) (abbreviation: Ir(p-PF-ph)2(acac)), bis(2-phenylbenzothiazole-N,C 2' ) iridium(III) (abbreviation: Ir(bt)2(acac)), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)-5-methylpyrazine]iridium(III) (abbreviation: Ir(Fdppr-Me)2(acac)), (acetylacetonato)bis{2-(4-methoxyphenyl)-3,5-dimethylpyrazine}iridium(III) (abbreviation: Ir(dmmoppr)2(acac)), etc. Examples of materials for orange light-emitting materials include: Tris(2-phenylquinoline-N,C 2′ ) iridium(III) (abbreviation: Ir(pq)3), bis(2-phenylquinoline-N,C acetylacetonato)iridium(III) 2′ ) (abbreviation: Ir(pq)2(acac)), (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)), etc. Examples of materials for red light-emitting materials include: Organometallic complexes, for example, bis[2-(2'-benzo[4,5-α]thienyl)pyridine-N,C acetylacetonato]iridium(III) 3')Iridium(III) bis(1-phenylisoquinoline-N,C acetylacetonate) (abbreviation: Ir(btp)2(acac)), 2' )Iridium(III) bis(2-phenylisoquinoline-N,C acetylacetonate) (abbreviation: Ir(piq)2(acac)), iridium(III) bis[2,3-bis(4-fluorophenyl)quinoxaline]acetylacetonate (abbreviation: Ir(Fdpq)2(acac)), iridium(III) bis(2,3,5-triphenylpyrazine)acetylacetonate (abbreviation: [Ir(tppr)2(acac)]), iridium(III) bis(2,3,5-triphenylpyrazine)bis(neopentanoylacetonate) (abbreviation: [Ir(tppr)2(dpm)]), and platinum(II) octaethyl-21H,23H-porphine (abbreviation: PtOEP). In addition, rare-earth metal complexes such as terbium(III) tris(acetylacetonate)(phenanthroline) (abbreviation: Tb(acac)3(Phen)), europium(III) tris(1,3-diphenyl-1,3-propanedionato)(phenanthroline) (abbreviation: Eu(DBM)3(Phen)), and europium(III) tris[1-(2-thienoyl)-3,3,3-trifluoroacetonate](phenanthroline) (abbreviation: Eu(TTA)3(Phen)) emit light (electron transfer between different multiplets) from rare-earth metal ions and thus can be used as phosphorescent compounds.

[0292] A polymer compound can be used as a luminescent material. Specifically, blue-light emitting materials, green-light emitting materials, and orange-to-red light emitting materials are shown. Examples of materials for blue-light emitting materials include: poly(9,9-dioctylfluorene-2,7-diyl) (abbreviation: PFO), [(9,9-dioctylfluorene-2,7-diyl)-(2,5-dimethoxybenzene-1,4-diyl)] copolymer (abbreviation: PF-DMOP), {(9,9-dioctylfluorene-2,7-diyl)-[N,N'-bis-(p-butylphenyl)-1,4-diaminobenzene]} copolymer (abbreviation: TAB-PFH), etc. Examples of materials for green-light emitting materials include: poly(p-phenylene vinylene) (abbreviation: PPV), [(9,9-dihexylfluorene-2,7-diyl)-(benzothieno[2,1,3]thiadiazole-4,7-diyl) alternating copolymer] (abbreviation: PFBT), [(9,9-dioctyl-2,7-divinylenefluorenylene)-(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene) alternating copolymer, etc. Examples of materials for orange-to-red light emission include: poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene] (abbreviation: MEH-PPV), poly(3-butylthiophene-2,5-diyl) (abbreviation: R4-PAT), {[9,9-dihexyl-2,7-bis(1-cyanovinylene)fluorenylene]-[2,5-bis(N,N'-diphenylamino)-1,4-phenylene]} alternating copolymer, {[2-methoxy-5-(2-ethylhexyloxy)-1,4-bis(1-cyanovinylenephenylene)]-[2,5-bis(N,N'-diphenylamino)-1,4-phenylene]} alternating copolymer (abbreviation: CN-PPV-DPD), etc.

[0293] It should be noted that the light-emitting layer 113 may have a structure in which the above-mentioned luminescent material (guest material) is dispersed in another material (host material). A variety of materials can be used as the host material, and it is preferable to use a material with the lowest unoccupied molecular orbital energy level (LUMO energy level) higher than that of the luminescent material and the highest occupied molecular orbital energy level (HOMO energy level) lower than that of the luminescent material.

[0294] The carbazole compound of one embodiment of the present invention has a wide bandgap (high S1 energy level), and thus can also be preferably used as the host material of the light-emitting layer 113.

[0295] In the case where the luminescent material is a phosphorescent compound, it is preferable to use a material with a T1 energy level higher than that of the luminescent material as the host material of the luminescent material.

[0296] The carbazole compound of one embodiment of the present invention has a high T1 energy level, and thus can also be preferably used as the host material of the phosphorescent material.

[0297] Specific examples of host materials that can be used in addition to the above include: tris(8-hydroxyquinoline)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenolate)aluminum(III) (abbreviation: BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolate]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolate]zinc(II) (abbreviation: ZnBTZ); heterocyclic compounds such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), bathophenanthroline (abbreviation: BPhen), and bathocuproine (BCP); fused aromatic compounds such as 9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-bis(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9′-bianthracene (abbreviation: BANT), 9,9′-(stilbene-3,3′-diyl)diphenanthrene (abbreviation: DPNS), 9,9′-(stilbene-4,4′-diyl)diphenanthrene (abbreviation: DPNS2), 3,3′,3″-(benzene-1,3,5-triyl)tripyrene (abbreviation: TPB3), 9,10-diphenylanthracene (abbreviation: DPAnth), and 6,12-dimethoxy-5,11-diphenyl Aromatic amine compounds, for example, N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), NPB (or α-NPD), TPD, DFLDPBi, BSPB, etc.

[0298] A variety of materials can be used as the host material. For example, in order to inhibit crystallization, a crystallization-inhibiting substance such as rubrene can be further added. In addition, NPB or Alq, etc. can be further added to effectively transfer energy to the guest material.

[0299] When adopting the structure in which the guest material is dispersed in the host material, crystallization of the light-emitting layer 113 can be inhibited. In addition, concentration quenching caused by the high concentration of the guest material can be inhibited.

[0300] The electron transport layer 114 is a layer containing a substance with high electron transport properties. Examples of substances with high electron transport properties include: metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as tris(8-hydroxyquinoline)aluminum (abbreviation: Alq), tris(4-methyl-8-hydroxyquinoline)aluminum (abbreviation: Almq3), bis(10-hydroxybenzo[h]-quinoline)beryllium (abbreviation: BeBq2), and bis(2-methyl-8-hydroxyquinoline)(4-phenylphenolate)aluminum (abbreviation: BAlq). Metal complexes containing an oxazolyl or thiazolyl ligand can also be used, such as bis[2-(2-hydroxyphenyl)benzoxazole]zinc (abbreviation: Zn(BOX)2) or bis[2-(2-hydroxyphenyl)benzothiazole]zinc (abbreviation: Zn(BTZ)2). In addition to metal complexes, the following substances can also be used: 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), bathocuproine (abbreviation: BCP), etc. The substances given here mainly have an electron mobility greater than or equal to 10 -6 cm 2Those substances with / V·s. It should be noted that the electron transport layer is not limited to a single layer and can be a laminate of two or more layers containing any of the above substances.

[0301] The electron injection layer 115 is a layer containing a substance with high electron injection properties. For the electron injection layer 115, an alkali metal, an alkaline earth metal, or a compound thereof can be used, such as lithium, cesium, calcium, lithium fluoride, cesium fluoride, calcium fluoride, or lithium oxide. A rare earth metal compound such as erbium fluoride can also be used. Any of the above substances can also be used to form the electron transport layer 114.

[0302] Alternatively, a composite material formed by mixing an organic compound with an electron donor (donor) can be used for the electron injection layer 115. Such a composite material has excellent electron injection properties and electron transport properties because it can generate electrons in the organic compound through the electron donor. In this case, the organic compound is preferably a material with excellent performance in transporting the generated electrons. Specifically, for example, the above materials (such as metal complexes or heteroaromatic compounds) used to form the electron transport layer 114 can be used. A substance that shows an electron-donating property to the organic compound can be used as the electron donor. Alkali metals, alkaline earth metals, or rare earth metals such as lithium, cesium, magnesium, calcium, erbium, or ytterbium are preferably used. In addition, alkali metal oxides or alkaline earth metal oxides such as lithium oxide, calcium oxide, or barium oxide are preferably used. A Lewis base such as magnesium oxide can also be used. An organic compound such as tetrathiafulvalene (abbreviation: TTF) can also be used.

[0303] It should be noted that the above hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, and electron injection layer 115 can each be formed by methods such as evaporation (e.g., vacuum evaporation), inkjet printing, or coating.

[0304] When the second electrode 103 is used as a cathode, the electrode can be formed using a metal, alloy, conductive compound, and their mixtures, etc., with a low work function (preferably, the work function is less than or equal to 3.8 eV). Specifically, any of the following materials can be used: aluminum or silver; elements belonging to Group 1 or Group 2 of the periodic table, i.e., alkali metals such as lithium or cesium, or alkaline earth metals such as magnesium, calcium, or strontium, alloys of the above metals (such as Mg - Ag or Al - Li); rare earth metals such as europium or ytterbium; or alloys of the above metals, etc.

[0305] It should be noted that in the EL layer 102, when the layer formed in contact with the second electrode 103 is formed of a composite material, various conductive materials such as Al, Ag, ITO, indium tin oxide containing silicon or silicon oxide can be used regardless of the work function, and the composite material is the one formed by mixing the above-mentioned organic compound with an electron donor.

[0306] Note that the second electrode 103 can be formed by a vacuum evaporation method or a sputtering method. In the case of using silver paste or the like, a coating method, an inkjet method, or the like can be adopted.

[0307] In the above-described light-emitting element, since a potential difference is generated between the first electrode 101 and the second electrode 103 and holes and electrons recombine in the EL layer 102, a current is generated, thereby causing light emission. Then, the emitted light is extracted through one or both of the first electrode 101 and the second electrode 103. Therefore, one or both of the first electrode 101 and the second electrode 103 are electrodes having a property of transmitting visible light.

[0308] Note that the layer structure between the first electrode 101 and the second electrode 103 is not limited to the above structure. A structure different from the above can also be adopted, as long as there is a light-emitting region where holes and electrons recombine in a portion far from the first electrode 101 and the second electrode 103 to prevent quenching caused by the proximity of the light-emitting region to the metal.

[0309] That is, there is no particular limitation on the stacking structure of the layers, and layers formed of a substance having a high electron transport property, a substance having a high hole transport property, a substance having a high electron injection property, a substance having a high hole injection property, a bipolar substance (a substance having a high electron transport property and a high hole transport property), a hole blocking substance, etc. can be freely combined with the light-emitting layer.

[0310] In Figure 1B In the shown light-emitting element, the EL layer 102 is disposed between the first electrode 101 and the second electrode 103 on the substrate 100. The EL layer 102 includes a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115. Figure 1B The light-emitting element in includes: a second electrode 103 serving as a cathode on the substrate 100; an electron injection layer 115, an electron transport layer 114, a light-emitting layer 113, a hole transport layer 112, and a hole injection layer 111, which are stacked on the second electrode 103 in the above order; and a first electrode 101 serving as an anode above the hole injection layer 111.

[0311] In addition, the HOMO energy level of the carbazole compound according to an embodiment of the present invention is deep, and its LUMO energy level is shallow. Moreover, the carbazole compound has a wide bandgap. For these reasons, the carbazole compound can be preferably used as a carrier transport layer (for example, a hole transport layer, an electron transport layer, or a hole blocking layer) adjacent to the light-emitting layer. Using the carbazole compound can obtain a high-efficiency element.

[0312] The specific manufacturing method of the light-emitting element will be described below.

[0313] The light-emitting element of the present embodiment has a structure in which an EL layer is interposed between a pair of electrodes. The electrodes (the first electrode or the second electrode) and the EL layer can be formed by a wet method such as a droplet discharge method (inkjet method), a spin coating method, or a printing method, or by a dry method such as a vacuum evaporation method, a CVD method, or a sputtering method. When using a wet method, it can be formed at normal pressure with a simple device and by a simple method, which can simplify the process and improve productivity. Different from the wet method, the dry method does not require dissolving the material and can use materials with low solubility in solution, expanding the material selection range.

[0314] All the thin films included in the light-emitting element can be formed by a wet method. In this case, the light-emitting element can be manufactured only with the equipment required for the wet method. Alternatively, the formation of the stacked layer up to the formation of the light-emitting layer can be carried out by a wet method, while the functional layer, the first electrode, etc. stacked on the light-emitting layer can be formed by a dry method. Or, the second electrode and the functional layer are formed by a dry method before forming the light-emitting layer, while the light-emitting layer, the functional layer stacked thereon, and the first electrode can be formed by a wet method. Needless to say, the present embodiment is not limited thereto, and the wet method or the dry method can be appropriately selected to form the light-emitting element according to the materials used, the required film thickness, and the interface state.

[0315] As described above, a light-emitting element can be made using the carbazole compound of an embodiment of the present invention. A light-emitting element with high luminous efficiency is obtained according to an embodiment of the present invention. Moreover, a light-emitting element with a long lifespan can be obtained.

[0316] In addition, a light-emitting device (such as an image display device) using the light-emitting element of an embodiment of the present invention prepared as described above can have low power consumption.

[0317] It should be noted that by using the light-emitting element described in the present embodiment, a passive matrix light-emitting device or an active matrix light-emitting device can be manufactured, in which the driving of the light-emitting element is controlled by a thin film transistor (TFT).

[0318] The present embodiment can be implemented in appropriate combination with any other embodiment.

[0319] (Embodiment 3)

[0320] In the present embodiment, it will be described in combination with Figure 2A and 2B a mode of a light-emitting element having a plurality of stacked light-emitting units (hereinafter referred to as a stacked type element) in the structure. The light-emitting element is a light-emitting element including a plurality of light-emitting units between a first electrode and a second electrode.

[0321] In Figure 2AIn this case, between the first electrode 301 and the second electrode 303, the first light-emitting unit 311 and the second light-emitting unit 312 are stacked together. In this embodiment, the first electrode 301 serves as the anode, and the second electrode 303 serves as the cathode. The first electrode 301 and the second electrode 303 may be the same as the electrodes in Embodiment 2. In addition, the first light-emitting unit 311 and the second light-emitting unit 312 may have the same or different structures. The first light-emitting unit 311 and the second light-emitting unit 312 may be the same as the structures in Embodiment 2, or any one of them may be different from the structure in Embodiment 2.

[0322] In addition, there is a charge generation layer 313 between the first light-emitting unit 311 and the second light-emitting unit 312. The function of the charge generation layer 313 is to inject electrons into one light-emitting unit and holes into the other light-emitting unit by applying a voltage between the first electrode 301 and the second electrode 303. In this embodiment, a voltage is applied to the first electrode 301 such that its potential is higher than that of the second electrode 303, and the charge generation layer 313 injects electrons into the first light-emitting unit 311 and holes into the second light-emitting unit 312.

[0323] It should be noted that the charge generation layer 313 preferably has the property of transmitting visible light in terms of light extraction efficiency. In addition, the charge generation layer 313 still functions even when its conductivity is less than that of the first electrode 301 or the second electrode 303.

[0324] The structure of the charge generation layer 313 may include an organic compound having a high hole transport property and an electron acceptor, or include an organic compound having a high electron transport property and an electron donor. Alternatively, these structures may be stacked. It should be noted that the electron acceptor and the electron donor can at least provide and accept electrons under the action of an electric field.

[0325] If an electron acceptor is added to an organic compound having a high hole transport property in the structure, a carbazole compound of an embodiment of the present invention may be used as the organic compound having a high hole transport property. In addition, arylamine compounds such as NPB, TPD, TDATA, MTDATA, or 4,4′-bis[N-(spiro-9,9′-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), etc. may be used. The substances mentioned here mainly have a hole mobility greater than or equal to 10 -6 cm 2 / V·s. Note that substances other than the above substances may be used as long as they are organic compounds with a hole transport property higher than the electron transport property.

[0326] Examples of electron acceptors include 7,7,8,8 - tetracyano - 2,3,5,6 - tetrafluoroquinodimethane (abbreviation: F4 - TCNQ), chloranil, etc. In addition, transition metal oxides are given. Oxides of metals in Groups 4 - 8 of the periodic table can also be used. Specifically, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide are preferably used because they have high electron - accepting properties. Among them, molybdenum oxide is particularly preferred because it is stable in air, has low hygroscopicity, and is easy to handle.

[0327] Conversely, when an electron donor is added to an organic compound having high electron - transport properties in the structure, for example, a metal complex having a quinoline skeleton or a benzoquinoline skeleton can be used as the organic compound having high electron - transport properties, such as Alq, Almq3, BeBq2, or BAlq, etc. Alternatively, a metal complex having an oxazolyl ligand or a thiazolyl ligand can be used, such as Zn(BOX)2 or Zn(BTZ)2. Alternatively, in addition to metal complexes, PBD, OXD - 7, TAZ, BPhen, BCP, etc. can be used. The substances mentioned here mainly have an electron mobility greater than or equal to 10 -6 cm 2 / V·s. Note that substances other than the above - mentioned substances can be used as long as they are organic compounds with higher electron - transport properties than hole - transport properties.

[0328] In addition, as electron donors, alkali metals, alkaline earth metals, rare earth metals, metals in Group 13 of the periodic table, or their oxides or carbonates can be used. Specifically, lithium, cesium, magnesium, calcium, ytterbium, indium, lithium oxide, cesium carbonate, etc. are preferably used. Alternatively, an organic compound such as tetrathiafulvalene can be used as an electron donor.

[0329] It should be noted that by using any of the above - mentioned materials to form the charge - generation layer 313, an increase in the driving voltage caused by the lamination of the EL layers can be suppressed.

[0330] In the present embodiment, a light - emitting element having two light - emitting units is described. One embodiment of the present invention can be similarly applied to a light - emitting element having three or more light - emitting units, as Figure 2B shown. Like the light - emitting element of the present embodiment, a plurality of light - emitting units separated by a charge - generation layer are provided between a pair of electrodes. Therefore, a light - emitting element with a long lifespan can be provided, and it can emit light with brightness while maintaining a low current density.

[0331] In addition, when the light-emitting units emit light of different colors, light emission of a desired color can be obtained from the light-emitting element as a whole. For example, in a light-emitting element including two light-emitting units, where the first light-emitting unit emits one color and the second light-emitting unit emits a complementary color, it is possible to obtain a light-emitting element that emits white light as a whole. It should be noted that "complementary color" means a color that produces an achromatic color when mixed. In other words, when light obtained from substances that emit complementary colors is mixed, white light emission can be obtained. This can also be applied to a light-emitting element including three or more light-emitting units. For example, when the first light-emitting unit emits red light, the second light-emitting unit emits green light, and the third light-emitting unit emits blue light, the entire light-emitting element can emit white light.

[0332] It should be noted that this embodiment can be freely combined with any other embodiment.

[0333] (Embodiment 4)

[0334] In this embodiment, reference is made to Figure 3A and 3B to describe a light-emitting device having a light-emitting element according to an embodiment of the present invention. Figure 3A is a top view showing the light-emitting device. Figure 3B is Figure 3A a cross-sectional view along lines A-B and C-D in

[0335] In Figure 3A reference numeral 401 indicates a drive circuit portion (source-side drive circuit), reference numeral 402 indicates a pixel portion, reference numeral 403 indicates a drive circuit portion (gate-side drive circuit), and they are shown by dashed lines. Reference numeral 404 indicates a sealing substrate, reference numeral 405 indicates a sealing material, and the portion surrounded by the sealing material 405 is a space.

[0336] It should be noted that the lead 408 is used to transmit signals, input signals to the source-side drive circuit 401 and the gate-side drive circuit 403, and receive an image signal, a clock signal, a start signal, a reset signal, etc. from a flexible printed circuit (FPC) 409, and the FPC 409 serves as an external input terminal. Although only the FPC is shown, the FPC can be connected to a printed wiring board (PWB). In the present specification, the light-emitting device includes not only the light-emitting device itself in terms of its classification, but also a light-emitting device provided with an FPC or a PWB.

[0337] Next, the cross-sectional structure will be described with reference to Figure 3B A drive circuit portion and a pixel portion are formed on the element substrate 410. Here, one pixel in the pixel portion 402 and the source-side drive circuit 401 as the drive circuit portion are shown in the figure.

[0338] Note that the CMOS circuit formed by combining the n-channel TFT 423 and the p-channel TFT 424 serves as the source-side driving circuit 401. The driving circuit may be various types of circuits formed using TFTs, such as CMOS circuits, PMOS circuits, or NMOS circuits. Although the driving circuit described in this embodiment is a driving-integrated circuit formed on a substrate, the present invention is not limited to this type, and the driving circuit may be formed outside the substrate.

[0339] The pixel portion 402 includes a plurality of pixels, which include 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. Here, the insulator 414 is formed using a positive photosensitive acrylic resin film.

[0340] To improve coverage, when providing the insulator 414, its upper end portion or lower end portion has a curved surface with a certain curvature. For example, when using a positive photosensitive acrylic resin as the material of the insulator 414, it is preferable that the insulator 414 has a curved surface with a certain radius of curvature (0.2 - 3 μm) only at the upper end portion. The insulator 414 may be formed using a negative material that is insoluble in an etchant under light irradiation or a positive photosensitive material that is soluble in an etchant under light irradiation.

[0341] An EL layer 416 and a second electrode 417 are formed on the first electrode 413. Here, it is preferable to use a material having a high work function as the material for forming the first electrode 413 (as an anode). For example, a single-layer ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 - 20 wt% zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, etc., a laminate including a titanium nitride film and a film mainly containing aluminum, a three-layer structure of a titanium nitride film, a film mainly containing aluminum, and a titanium nitride film, etc. may be used. Note that the laminated structure enables a low resistance of the wire and good ohmic contact to be obtained.

[0342] Any method may be employed, such as an evaporation method using an evaporation mask, a droplet discharge method such as an inkjet method, a printing method, and a spin coating method to form the EL layer 416. The EL layer 416 contains the carbazole compound described in Embodiment 1. In addition, another substance contained in the EL layer 416 may be a low molecular material, an oligomer, a dendritic polymer, a high molecular material, etc.

[0343] Preferably, a material with a low work function (such as Al, Mg, Li, Ca, or their alloys or compounds, such as Mg - Ag, Mg - In, or Al - Li) is used as the material for the second electrode 417, which is formed on the EL layer 416 and serves as the cathode. To allow the light generated in the EL layer 416 to transmit through the second electrode 417, the second electrode 417 can be formed of a stack of a thin metal film with a small thickness and a transparent conductive film (such as ITO, indium oxide containing 2 - 20 wt% zinc oxide, indium tin oxide containing silicon or silicon oxide, or zinc oxide (ZnO)).

[0344] The sealing substrate 404 is attached to the element substrate 410 with a sealant 405; thus, a light - emitting element 418 is provided in a space 407 surrounded by the element substrate 410, the sealing substrate 404, and the sealant 405. It should be noted that the space 407 is filled with a filler such as an inert gas (such as nitrogen or argon) or the sealing material 405.

[0345] Note that it is preferable to use an epoxy - based resin as the sealant 405. A material that is preferably as impermeable to moisture or oxygen as possible is used. In addition to a glass substrate or a quartz substrate, a plastic substrate formed of FRP (fiber - reinforced plastic), PVF (polyvinyl fluoride), polyester, acrylic material, etc. can also be used as the material for the sealing substrate 404.

[0346] As described above, an active - matrix light - emitting device having a light - emitting element according to an embodiment of the present invention can be obtained.

[0347] In addition, a light - emitting element according to an embodiment of the present invention can be used in a passive - matrix light - emitting device as well as the above - mentioned active - matrix light - emitting device. Figure 4A and 4B A perspective view and a cross - sectional view of a passive - matrix light - emitting device using a light - emitting element according to an embodiment of the present invention are shown. Figure 4A is a perspective view of the light - emitting device. Figure 4B is along Figure 4A the X - Y line in

[0348] In Figure 4A and 4BIn this case, an EL layer 504 is provided between a first electrode 502 and a second electrode 503 on a substrate 501. An end portion of the first electrode 502 is covered with an insulating layer 505. Further, a partition layer 506 is provided on the insulating layer 505. Side walls of the partition layer 506 are inclined such that a distance between one side wall and the other side wall gradually decreases in a direction toward the substrate surface. In other words, a cross section of the partition layer 506 in a narrow side direction is trapezoidal, and a length of a bottom side (a side in contact with the insulating layer 505, which is one of a pair of parallel sides of the trapezoidal cross section) is smaller than a length of a top side (a side not in contact with the insulating layer 505, which is the other of the pair of parallel sides). By providing the partition layer 506 in this manner, defects of a light-emitting element due to interference or the like can be prevented.

[0349] As described above, a passive matrix light-emitting device including a light-emitting element according to an embodiment of the present invention can be obtained.

[0350] In the light-emitting devices (active matrix light-emitting devices and passive matrix light-emitting devices) described in this embodiment, the light-emitting elements described in an embodiment of the present invention can be used, and thus, power consumption is low.

[0351] It should be noted that this embodiment can be freely combined with any other embodiment as appropriate.

[0352] (Embodiment 5)

[0353] In this embodiment, examples of various electronic devices and lighting devices using a light-emitting device according to an embodiment of the present invention will be described with reference to Figures 5A to 5E and Figure 6 Examples of electronic devices using the light-emitting device include a television device (also referred to as a TV or a television receiver), a computer display, etc., a camera such as a digital camera or a digital video camera, a digital photo frame, a mobile phone (also referred to as a portable telephone), a portable game machine, a portable information terminal, an audio playback device, a large game machine such as a pachinko machine, etc.

[0354] Specific examples of these electronic devices and lighting devices are shown. Figures 5A - 5E Examples of these electronic devices and lighting devices are shown.

[0355] Figure 5A A television device 7100 is described. In the television device 7100, a display section 7103 is incorporated in a housing 7101. The display section 7103 can display an image, and a light-emitting device can be used for the display section 7103. Further, in this document, the housing 7101 is supported by a bracket 7105.

[0356] The television device 7110 can be manipulated by the operation switch of the outer shell 7100 or an independent remote controller 7101. The channel can be adjusted and the volume can be controlled by using the control keys 7109 of the remote controller 7110, thereby controlling the image displayed on the display part 7103. A display part 7107 can be provided on the remote controller 7110 to display the display data output from the remote controller 7110.

[0357] Note that a receiver, a modem, etc. are provided for the television device 7100. General television broadcasts can be received by the receiver. In addition, when the television device 7100 is connected to a communication network by wire or wirelessly through a modem, one-way (from the sender to the receiver) or two-way (between the sender and the receiver, between the receivers, etc.) information exchange can be carried out.

[0358] Figure 5B A display computer includes a main body 7201, an outer shell 7202, a display part 7203, a keyboard 7204, an external connection port 7205, a click device 7206, etc. This computer is made using the light-emitting devices of the display part 7203.

[0359] Figure 5C A display portable game console includes two outer shells, namely an outer shell 7301 and an outer shell 7302, which are connected by a connecting member 7303, so that this portable game console can be opened or folded. A display part 7304 is incorporated in the outer shell 7301, and a display part 7305 is incorporated in the outer shell 7302. In addition, Figure 5C the shown portable game console includes a speaker part 7306, a recording medium insertion part 7307, an LED lamp 7308, an input device (control keys 7309, connection terminals 7310, a sensor 7311 (a sensor having the function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation frequency, distance, brightness, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays) or a microphone 7312), etc. It goes without saying that the structure of the portable game console is not limited to the above description, as long as the light-emitting devices can be used at least for the display part 7304 or the display part 7305, or for both at the same time, and other accessories can be included under appropriate circumstances. Figure 5C The portable game console has the following functions: reading the programs or data stored in the storage medium, displaying them on the display part, and sharing information with another portable game console through wireless communication. Figure 5C The shown portable game console has various functions and is not limited to the above functions.

[0360] Figure 5DAn example of a mobile phone is shown. The mobile phone 7400 has a display section 7402, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, etc. incorporated in a housing 7401. It should be noted that the mobile phone 7400 is made using a light-emitting device for the display section 7402.

[0361] When touching with a finger or the like Figure 5D the display section 7402 of the mobile phone 7400 shown, data can be input into the mobile phone 7400. The user can make a call and edit an email by touching the display section 7402 with a finger or the like.

[0362] The display section 7402 mainly has three screen modes. The first mode is a display mode mainly used for displaying images. The second mode is an input mode mainly used for inputting information such as text. The third mode is a display and input mode, which is a combination of the display mode and the input mode.

[0363] For example, when making a call or editing an email, the text input mode mainly used for inputting text is selected on the display section 7402 to input the text displayed on the screen. In this case, it is preferable to display a keyboard or numeric keys on almost the entire screen of the display section 7402.

[0364] When a detection device including a sensor for detecting inclination, such as a gyroscope or an acceleration sensor, is provided inside the mobile phone 7400, the direction of the mobile phone 7400 (whether the mobile phone is placed horizontally or vertically, for landscape mode or portrait mode) is detected, and the screen display of the display section 7402 can be automatically switched.

[0365] The screen mode is switched by touching the display section 7402 or operating the operation buttons 7403 of the housing 7401. Or the screen mode can be switched according to the type of image displayed on the display section 7402. For example, when the image signal displayed on the display section is a moving image data signal, the screen mode is switched to the display mode. When the signal is a text data signal, the screen mode is switched to the input mode.

[0366] In addition, in the input mode, if the optical sensor of the display section 7402 detects a signal and the touch input on the display section 7402 has not been performed for a certain period of time, the screen mode can be controlled to switch from the input mode to the display mode.

[0367] The display section 7402 can function as an image sensor. For example, the display section 7402 comes into contact with a palm or a finger to obtain images of a palm print, a fingerprint, etc., thereby performing personal identity verification. Additionally, when a backlight or a sensing light source that emits near-infrared light is provided in the display section, images of a fingerprint, a palm print, etc. can be obtained.

[0368] Figure 5E Disclosed is a desk lamp, which includes an illumination section 7501, a lampshade 7502, an adjustable arm 7503, a bracket 7504, a base 7505, and a power source 7506. This desk lamp is fabricated using a light-emitting device for the illumination section 7501. It should be noted that lamps include ceiling lamps, wall lamps, etc. in terms of their classification.

[0369] Figure 6 Examples of using the light-emitting device for indoor lighting devices are shown. Since the light-emitting device has a large area, the light-emitting device can be used as a lighting device with a large area. The light-emitting device can also be used as a scrollable lighting device 802. As Figure 6 shown, referring to Figure 5E the desk lamp 803 described above can also be used in a room where an indoor lighting device 801 is provided.

[0370] In the above manner, electronic devices and lighting devices can be fabricated using the light-emitting device. The application range of the light-emitting device is extremely wide, and the light-emitting device can be applied to various fields of electronic devices.

[0371] It should be noted that the structure described in this embodiment can be appropriately combined with any of the structures described in Embodiments 1-4.

[0372] [Example 1]

[0373] In this example, Synthesis Example 1 and Synthesis Example 2 for preparing 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN) represented by Structural Formula (100) in Embodiment 1 will be described.

[38]

[0375]

[0376] [Synthesis Example 1]

[0377] In a 200 mL three-necked flask, a mixture of 5.0 g (15.5 mmol) of 3-bromo-9-phenyl-9H-carbazole, 4.2 g (17.1 mmol) of 4-(1-naphthyl)phenylboronic acid, 38.4 mg (0.2 mmol) of palladium(II) acetate, 104 mg (0.3 mmol) of tris(2-methylphenyl)phosphine, 50 mL of toluene, 5 mL of ethanol, and 30 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 85 °C for 9 hours under a nitrogen atmosphere to carry out the reaction.

[0378] After the reaction, 500 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered by suction through Florisil (produced by Wako Pure Chemical Industries, Ltd., catalog number 540-00135), alumina (neutral, produced by Merck Ltd), and C salt (Celite) (produced by Wako Pure Chemical Industries, Ltd., catalog number 531-16855). The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:4) was used as the elution solvent for chromatography. The concentrated fraction was concentrated, and methanol was added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 6.24 g of the target substance as a white powder, with a yield of 90%. The reaction scheme of Synthesis Example 1 is shown in (F1-1).

[39]

[0380]

[0381] The Rf values of the target substance and 3-bromo-9-phenyl-9H-carbazole were 0.42 and 0.58, respectively, and these measured values were obtained by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane at a ratio of 1:10).

[0382] The compound obtained in Synthesis Example 1 was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0383] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.30 - 7.35 (m, 1H), 7.44 - 7.67 (m, 14H), 7.76 (dd, J = 8.7 Hz, 1.8 Hz, 1H), 7.84 - 7.95 (m, 4H), 8.04 (d, J = 7.8, 1H), 8.23 (d, J = 7.8, 1H), 8.46 (d, J = 1.5, 1H).

[0384] Figure 7A and 7B is 1 the \(^1\)H NMR spectrum. It should be noted that Figure 7B is Figure 7A an enlarged view in the range of 7.0 ppm to 9.0 ppm. The test results confirm that the target substance 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN) can be obtained.

[0385] <Synthesis Example 2>

[0386] In this synthesis example, a synthesis example of PCPN different from Synthesis Example 1 is described.

[0387] [Step 1: Synthesis method of 3-(4-bromophenyl)-9-phenyl-9H-carbazole]

[0388] In a 300 mL three-necked flask, a mixture of 14 g (50 mmol) of 4-bromoiodobenzene, 14 g (50 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, 110 mg (0.5 mmol) of palladium(II) acetate, 300 mg (1.0 mmol) of tris(ortho-tolyl)phosphine, 50 mL of toluene, 10 mL of ethanol, and 25 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 80 °C for 6 hours under a nitrogen atmosphere to carry out the reaction.

[0389] After the reaction, 200 mL of toluene was added to the reaction mixture solution, and the resulting suspension was filtered through Florisil and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:4) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and hexane was added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 15 g of the target substance as a white powder, with a yield of 75%. The reaction scheme for Step 1 is shown in (F1-2).

[40]

[0391]

[0392] The Rf values of the target substance and 4-bromoiodobenzene are 0.32 and 0.74, respectively, and these measured values were obtained by silica gel thin-layer chromatography (TLC) (the elution solvent is ethyl acetate and hexane at a ratio of 1:10).

[0393] The compound obtained in Step 1 was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0394] 11H NMR (CDCl3, 300 MHz): δ (ppm) = 7.24 - 7.32 (m, 1H), 7.40 - 7.64 (m, 13H), 8.17 (d, J = 7.2 Hz, 1H), 8.29 (s, 1H).

[0395] Figure 8A and 8B is 1 the 1H NMR spectrum. It should be noted that Figure 8B is Figure 8A an enlarged view in the range of 7.0 ppm to 8.5 ppm. The test results confirm that the target substance 3-(4-bromophenyl)-9-phenyl-9H-carbazole can be obtained.

[0396] The molecular weight of the above compound was measured using a GC-MS detector (ITQ1100 ion trap GC / MS system, manufactured by ThermoFisher Scientific K.K). Figure 9 This is its spectrum. The main peak with a measured molecular weight of 397.13 (mode: EI+) was obtained. The test results confirm that the target substance 3-(4-bromophenyl)-9-phenyl-9H-carbazole can be obtained.

[0397] [Step 2: Synthesis method of 3-(4-(1-naphthyl)phenyl)-9-phenyl-9H-carbazole (abbreviation: PCPN)]

[0398] In a 50 mL three-necked flask, a mixture of 2.4 g (5.0 mmol) of 3-(4-bromophenyl)-9-phenyl-9H-carbazole, 1.1 g (5.5 mmol) of naphthalene-1-boronic acid, 20 mg (0.1 mmol) of palladium(II) acetate, 36 mg (0.1 mmol) of tris(o-tolyl)phosphine, 10 mL of toluene, 1.5 mL of ethanol, and 5 mL of potassium carbonate aqueous solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 90 °C for 14 hours under a nitrogen atmosphere to carry out the reaction.

[0399] After the reaction, 200 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:4) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and acetone and methanol were added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 2.3 g of the target substance as a white powder, with a yield of 86%. The reaction scheme of Step 2 is shown in (F1-3).

[41]

[0401]

[0402] The Rf values of the target substance and 3-(4-bromophenyl)-9-phenyl-9H-carbazole were 0.57 and 0.65, respectively, and these measured values were obtained by silica gel thin layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane at a ratio of 1:10).

[0403] In addition, nuclear magnetic resonance (NMR) confirmed that the compound obtained in Synthesis Example 2 was the target substance 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN).

[0404] Figure 10A Show the absorption spectrum of PCPN in a toluene solution of PCPN, Figure 10B Show its emission spectrum. Figure 11A Show the absorption spectrum of the PCPN thin film, Figure 11B Show its emission spectrum. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics Corporation). The samples were measured in the following manner: The solution was placed in a quartz cell, and a thin film was obtained on the quartz substrate by evaporation. Figure 10A Show the absorption spectrum of PCPN in a PCPN solution, obtained by subtracting the absorption spectra of the quartz cell and the toluene placed therein. Figure 11A Show the absorption spectrum of the thin film, obtained by subtracting the absorption spectrum of the quartz substrate. In Figure 10A and 10B as well as Figure 11A and 11B the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary unit). For the case of the toluene solution, an absorption peak was observed at approximately 300 nm, and the maximum emission wavelength was 384 nm (excitation wavelength: 320 nm). For the case of the thin film, an absorption peak was observed at approximately 322 nm, and the maximum emission wavelength was 398 nm (excitation wavelength: 324 nm).

[0405] The absorption spectrum shows that the PCPN described in this example is a material with weak absorption of light in the visible range. Additionally, the emission spectrum shows that PCPN exhibits blue-violet light emission.

[0406] [Example 2]

[0407] In this example, an example of preparing 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn) represented by the structural formula (102) in Preparation Method 1 will be described.

[42]

[0409]

[0410] [Step 1: Synthesis method of 4-(9-phenyl-9H-carbazol-3-yl)phenylboronic acid]

[0411] Add 8.0 g (20 mmol) of 3-(4-bromophenyl)-9-phenyl-9H-carbazole obtained in Reaction Scheme (F1-2) to a 300 mL three-necked flask. Replace the atmosphere in the flask with nitrogen, then add 100 mL of dehydrated tetrahydrofuran (abbreviation: THF) to the flask, and lower the temperature to -78 °C. Add 3.4 mL (30 mmol) of trimethyl borate to this mixture, stir the mixture with trimethyl borate added at -78 °C for 2 hours, and stir at room temperature for 18 hours. After the reaction, add 1 M dilute hydrochloric acid to the reaction solution until the solution becomes acidic, and stir the solution with dilute hydrochloric acid added for 7 hours. Perform ethyl acetate extraction on this solution, and wash the obtained organic layer with saturated brine. After washing, add magnesium sulfate to the organic layer to remove moisture. Filter this suspension, concentrate the resulting filtrate, and add hexane thereto. Irradiate this mixture with ultrasonic waves, and then perform recrystallization to obtain 6.4 g of the target substance as a white powder, with a yield of 88%. The reaction scheme of Step 1 is shown in (F2-1).

[43]

[0413]

[0414] The Rf values of the target substance and 3-(4-bromophenyl)-9-phenyl-9H-carbazole are 0 (origin) and 0.53, respectively, and these measured values are obtained by silica gel thin-layer chromatography (TLC) (the elution solvent is ethyl acetate and hexane with a ratio of 1:10). In addition, the Rf values of the target substance and 3-(4-bromophenyl)-9-phenyl-9H-carbazole are 0.72 and 0.93, respectively, and these measured values are obtained by silica gel thin-layer chromatography (TLC) using ethyl acetate as the elution solvent.

[0415] [Step 2: Synthesis method of 3-(4-(9-phenanthryl)phenyl)-9-phenyl-9H-carbazole (abbreviation: PCPPn)]

[0416] In a 200 mL three-necked flask, a mixture of 1.5 g (5.0 mmol) of 9-phenyl-9H-carbazol-3-yl-phenyl-4-boronic acid, 3.2 g (11 mmol) of 9-bromophenanthrene, 11 mg (0.1 mmol) of palladium(II) acetate, 30 mg (0.1 mmol) of tris(o-tolyl)phosphine, 30 mL of toluene, 3 mL of ethanol, and 5 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 90 °C under a nitrogen atmosphere for 6 hours to carry out the reaction.

[0417] After the reaction, 200 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:4) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and acetone and methanol were added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 2.2 g of the target substance as a white powder, with a yield of 75%. The reaction scheme of Step 2 is shown in (F2-2).

[0418]

[0419] The Rf values of the target substance and 9-bromophenanthrene were 0.33 and 0.70, respectively, and these measured values were obtained by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane in a ratio of 1:10).

[0420] The obtained compound was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0421] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.30 - 7.35 (m, 1H), 7.43 - 7.78 (m, 16H), 7.86 - 7.93 (m, 3H), 8.01 (dd, J = 0.9 Hz, 7.8 Hz, 1H), 8.23 (d, J = 7.8 Hz, 1H), 8.47 (d, J = 1.5 Hz, 1H), 8.74 (d, J = 8.1 Hz, 1H), 8.80 (d, J = 7.8 Hz, 1H).

[0422] Figure 12A and 12B is 1 the H NMR spectrum. It should be noted that Figure 12B is Figure 12A an enlarged view in the range of 7.0 ppm to 9.0 ppm. The test results confirmed that the target substance PCPPn (abbreviation) could be obtained.

[0423] Figure 13A Show the absorption spectrum of PCPPn in a toluene solution of PCPPn, Figure 13B and show its emission spectrum. Figure 14A Show the absorption spectrum of the PCPPn thin film, Figure 14A and show its emission spectrum. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics). Measurements were performed on samples prepared as follows: The solution was placed in a quartz cell, and a thin film was obtained on a quartz substrate by evaporation. Figure 13A Show the absorption spectrum of PCPPn in a PCPPn solution, obtained by subtracting the absorption spectra of the quartz cell and the toluene placed therein. Figure 14A Show the absorption spectrum of the thin film, obtained by subtracting the absorption spectrum of the quartz substrate. In Figure 13A and 13B as well as Figure 14A and 14B the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary units). For the case of the toluene solution, an absorption peak was observed at approximately 300 nm, and the maximum emission wavelength was 383 nm (excitation wavelength: 300 nm). For the case of the thin film, an absorption peak was observed at approximately 321 nm, and the maximum emission wavelength was 410 nm (excitation wavelength: 331 nm).

[0424] The absorption spectrum shows that the PCPPn described in this example is a material with weak absorption of light in the visible range. In addition, the emission spectrum shows that PCPPn exhibits blue-violet light emission.

[0425] Furthermore, the glass transition temperature (Tg) of PCPPn was detected using a differential scanning calorimeter (DSC). The measurement results show that the glass transition temperature is 114 °C. In this way, PCPPn has a high glass transition temperature and good heat resistance. In addition, no crystallization peak was observed, indicating that PCPPn is a substance that is difficult to crystallize.

[0426] [Example 3]

[0427] In this example, an instance of preparing 9-phenyl-3-[4-(benzo[9,10]phenanthren-2-yl)phenyl]-9H-carbazole (abbreviation: PCzPTp) represented by the structural formula (105) in Embodiment 1 will be described.

[45]

[0429]

[0430] In a 100 mL three-necked flask, a mixture of 0.5 g (2.0 mmol) of 2-bromobenzo[9,10]phenanthrene, 3.3 g (9.2 mmol) of 4-(9-phenyl-9H-carbazol-3-yl)phenylboronic acid, 20 mg (0.1 mmol) of palladium(II) acetate, 60 mg (0.2 mmol) of tris(o-tolyl)phosphine, 20 mL of toluene, 2 mL of ethanol, and 7.5 mL of aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 85 °C for 16 hours under a nitrogen atmosphere to carry out the reaction.

[0431] After the reaction, 500 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, toluene was used as the elution solvent for chromatography. The concentrated fraction was added with methanol. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain the target substance as a white powder. The reaction scheme of Step 1 is shown in (F3-1).

[46]

[0433]

[0434] The Rf values of the target substance and 2-bromobenzo[9,10]phenanthrene were 0.21 and 0.46, respectively, and these measured values were obtained by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane with a ratio of 1:10).

[0435] The obtained compound was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0436] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.31 - 7.36 (m, 1H), 7.45 - 7.53 (m, 4H), 7.61 - 7.78 (m, 9H), 7.89 - 8.01 (m, 5H), 8.24 (d, J = 7.5 Hz, 1H), 8.46 (d, J = 1.5 Hz, 1H), 8.67 - 8.82 (m, 5H), 8.95 (d, J = 2.1 Hz, 1H).

[0437] Figure 15A and 15B is 1 the H NMR spectrum. It should be noted that Figure 15B is Figure 15A an enlarged view in the range of 7.0 ppm to 9.5 ppm. The test results confirmed that the target substance PCzPTp could be obtained.

[0438] Figure 16A The absorption spectrum of PCzPTp in a toluene solution of PCzPTp is shown, Figure 16B and its emission spectrum is shown. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics). The measurement was carried out with the solution placed in a quartz cell. Figure 16A The absorption spectrum of PCzPTp in a PCzPTp solution, obtained by subtracting the absorption spectra of the quartz cell and the toluene placed therein, is shown. In Figure 16A and 16B , the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary unit). For the case of the toluene solution, an absorption peak was observed at approximately 325 nm, and the maximum emission wavelength was 385 nm (excitation wavelength: 347 nm).

[0439] The absorption spectrum shows that the PCzPTp described in this example is a material with weak absorption of light in the visible range. Additionally, the emission spectrum shows that PCzPTp emits blue-violet light.

[0440] [Example 4]

[0441] In this example, an instance of preparing 3-[3-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: mPCPPn) represented by the structural formula (108) in Embodiment 1 will be described.

[47]

[0443]

[0444] [Step 1: Synthesis method of 3-(3-bromophenyl)-9-phenyl-9H-carbazole]

[0445] In a 500 mL three-necked flask, a mixture of 31 g (110 mmol) of 3-bromoiodobenzene, 29 g (100 mmol) of 9-phenyl-9H-carbazole-3-boronic acid, 22 mg (0.1 mmol) of palladium(II) acetate, 60 mg (1.2 mmol) of tris(o-tolyl)phosphine, 100 mL of toluene, 10 mL of ethanol, and 50 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 80 °C for 2.5 hours under a nitrogen atmosphere to carry out the reaction.

[0446] After the reaction, 200 mL of toluene was added to the reaction mixture solution, and the resulting suspension was filtered through Florisil and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated, and toluene and methanol were added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 22 g of the target substance as a white powder, with a yield of 54%. The reaction scheme of Step 1 is shown in (F4-1).

[48]

[0448]

[0449] The Rf values of the target substance and 3-bromoiodobenzene were 0.29 and 0.67, respectively, and these measured values were obtained by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane with a ratio of 1:10).

[0450] [Step 2: Synthesis method of 3-(3-(9-phenanthryl)phenyl)-9-phenyl-9H-carbazole (abbreviation: mPCPPn)]

[0451] In a 200 mL three-necked flask, a mixture of 3.0 g (7.5 mmol) of 3-(3-bromophenyl)-9-phenyl-9H-carbazole, 1.8 g (8.29 mmol) of 9-phenanthreneboronic acid, 19 mg (0.1 mmol) of palladium(II) acetate, 76 mg (0.2 mmol) of tris(2-methylphenyl)phosphine, 70 mL of toluene, 7 mL of ethanol, and 20 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 100 °C for 5 hours under a nitrogen atmosphere to carry out the reaction.

[0452] After the reaction, 500 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 2:3) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and hexane was added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 2.76 g of the target substance as a white powder, with a yield of 74%. The reaction scheme of Step 2 is shown in (F4-2).

[49]

[0454]

[0455] The Rf values of the target substance and 3-(3-bromophenyl)-9-phenyl-9H-carbazole were 0.25 and 0.58, respectively, and these measurements were obtained by silica gel thin layer chromatography (TLC) (the elution solvent contained ethyl acetate and hexane in a ratio of 1:10).

[0456] The resulting compound was determined by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0457] 1 1H NMR (CDCl3, 300 MHz): δ (ppm) = 7.28 - 7.32 (m, 1H), 7.42 - 7.76 (m, 15H), 7.81 - 7.84 (m, 2H), 7.92 - 7.95 (m, 2H), 8.06 (d, J = 8.1 Hz, 1H), 8.18 (d, J = 7.8 Hz, 1H), 8.44 (d, J = 1.5 Hz, 1H), 8.76 (d, J = 8.1 Hz, 1H), 8.81 (d, J = 8.7 Hz, 1H).

[0458] Figure 17A and 17B is 1 the 1H NMR spectrum. It should be noted that Figure 17B is Figure 17A an enlarged view in the range of 6.5 ppm to 9.0 ppm. The test results confirmed that the target substance mPCPPn was obtained.

[0459] Figure 18A shows the absorption spectrum of mPCPPn in a toluene solution of mPCPPn, Figure 18B showing its emission spectrum. Figure 19A shows the absorption spectrum of the mPCPPn film, Figure 19B showing its emission spectrum. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics). The samples were measured in the following manner: the solution was placed in a quartz cell, and a film was obtained on a quartz substrate by evaporation. Figure 18A shows the absorption spectrum of mPCPPn in a solution of mPCPPn, obtained by subtracting the absorption spectra of the quartz cell and toluene placed therein. Figure 19A shows the absorption spectrum of the film, obtained by subtracting the absorption spectrum of the quartz substrate. In Figure 18A and 18B and Figure 19A and 19BAmong them, the horizontal axis represents wavelength (nm), and the vertical axis represents intensity (arbitrary unit). For the toluene solution, an absorption peak is observed at approximately 298 nm, and the maximum emission wavelength is 363 nm (excitation wavelength: 311 nm). For the thin film, an absorption peak is observed at approximately 350 nm, and the maximum emission wavelength is 389 nm (excitation wavelength: 353 nm).

[0460] The absorption spectrum shows that the mPCPPn described in this example is a material with weak absorption of light in the visible range. In addition, the emission spectrum shows that mPCPPn exhibits blue-violet light emission.

[0461] Furthermore, a differential scanning calorimeter (DSC) was used to detect the glass transition temperature (Tg) of mPCPPn. The measurement results show that the glass transition temperature is 109 °C. In this way, mPCPPn has a high glass transition temperature and good heat resistance. In addition, no crystallization peak was observed, indicating that mPCPPn is a substance that is difficult to crystallize.

[0462] [Example 5]

[0463] In this example, an example of preparing 9-phenyl-3-[3-(benzo[9,10]phenanthren-2-yl)phenyl]-9H-carbazole (abbreviation: mPCzPTp) represented by the structural formula (111) in Embodiment 1 will be described.

[50]

[0465]

[0466] In a 50 mL three-necked flask, a mixture of 0.7 g (1.8 mmol) of 3-bromo-9-phenyl-9H-carbazole, 0.5 g (1.8 mmol) of benzo[9,10]phenanthrene-2-boronic acid, 4.1 mg (18 μmol) of palladium(II) acetate, 28 mg (92 μmol) of tris(ortho-tolyl)phosphine, 6.9 mL of toluene, 2.3 mL of ethanol, and 1.9 mL of aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 80 °C for 3 hours in a nitrogen atmosphere for the reaction.

[0467] After the reaction, the aqueous layer of the obtained suspension was extracted with toluene. The obtained extraction solution and suspension were washed with saturated brine, and magnesium sulfate was added to the obtained solution to absorb water. The suspension was separated by gravity filtration, and the filtrate was concentrated to obtain an oily substance. The oily substance was purified by silica gel column chromatography. First, a mixed solvent of toluene and hexane (toluene:hexane = 1:9) was used as the elution solvent, and then a mixed solvent of toluene and hexane (toluene:hexane = 1:6) was used as the elution solvent for column chromatography. The obtained fractions were concentrated to obtain an oily substance. Toluene and hexane were added to the oily substance, and the mixture was crystallized to obtain 0.9 g of the target substance in the form of a white solid, with a yield of 90%. The reaction scheme of this synthesis method is shown in (F5-1).

[51]

[0469]

[0470] The obtained compound was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0471] 1 H NMR(CDCl3,300MHz):δ(ppm)=7.30-7.54(m,5H),7.60-7.80(m,12H),8.01(dd,J=8.4Hz,1.5Hz,1H),8.14(s,1H),8.23(d,J=7.8Hz,1H),8.47(d,J=2.1Hz,1H),8.67-8.80(m,5H),8.95(d,J=1.5Hz,1H).

[0472] Figure 20A and 20B is 1 the H NMR spectrum. It should be noted that Figure 20B is Figure 20A an enlarged view in the range of 7.0 ppm to 9.0 ppm. The test results confirmed that the target substance mPCzPTp could be obtained.

[0473] Figure 21A shows the absorption spectrum of mPCzPTp in the toluene solution of mPCzPTp, Figure 21B shows its emission spectrum. Figure 22A shows the absorption spectrum of the mPCzPTp film, Figure 22B shows its emission spectrum. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics Corporation). The samples were measured in the following manner: The solution was placed in a quartz cell, and a film was obtained on the quartz substrate by evaporation. Figure 21AThe absorption spectrum of mPCzPTp in an mPCzPTp solution was obtained by subtracting the absorption spectra of the quartz cell and toluene placed therein. Figure 22A The absorption spectrum of the thin film was obtained by subtracting the absorption spectrum of the quartz substrate. In Figure 21A and 21B as well as Figure 22A and 22B the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary unit). For the case of the toluene solution, an absorption peak was observed at approximately 290 nm, and the maximum emission wavelength was 381 nm (excitation wavelength: 290 nm). For the case of the thin film, an absorption peak was observed at approximately 277 nm, and the maximum emission wavelength was 397 nm (excitation wavelength: 306 nm).

[0474] The absorption spectrum shows that mPCzPTp described in this example is a material with weak absorption of light in the visible range. In addition, the emission spectrum shows that mPCzPTp exhibits blue-violet light emission.

[0475] [Example 6]

[0476] In this example, an example of preparing 9-(1-naphthyl)-3-[4-(1-naphthyl)phenyl]-9H-carbazole (abbreviation: NCPN) represented by the structural formula (120) in Embodiment 1 will be described.

[52]

[0478]

[0479] [Step 1: Synthesis method of 3-bromo-9-(1-naphthyl)-9H-carbazole]

[0480] In a 200 mL conical flask, 5.9 g (20 mmol) of 9-(1-naphthyl)-9H-carbazole was dissolved in a mixed solvent of 50 mL of toluene and 70 mL of ethyl acetate, and then 3.6 g (20 mmol) of N-bromosuccinimide (abbreviation: NBS) was added to this solution. The mixture was stirred at room temperature for 36 hours. After the reaction was completed, the mixed solution was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered, and the resulting filtrate was concentrated and collected. As a result, 7.4 g of a white powdery target substance was obtained, and the yield was 99%. The synthesis scheme of Step 1 is shown in (F6-1).

[53]

[0482]

[0483] [Step 2: Synthesis method of 9-(1-naphthyl)-3-[4-(1-naphthyl)phenyl]-9H-carbazole (abbreviation: NCPN)]

[0484] In a 200 mL three-necked flask, a mixture of 5.0 g (13 mmol) of 3-bromo-9-(1-naphthyl)-9H-carbazole, 3.7 g (15 mmol) of 4-(1-naphthyl)phenylboronic acid, 34 mg (0.2 mmol) of palladium(II) acetate, 91 mg (0.3 mmol) of tris(2-methylphenyl)phosphine, 50 mL of toluene, 5 mL of ethanol, and 30 mL of aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 100 °C under a nitrogen atmosphere for 1 hour to carry out the reaction. In addition, 334 mg (1.35 mmol) of 4-(1-naphthyl)phenylboronic acid, 15.0 mg (0.07 mmol) of palladium(II) acetate, and 45 mg (0.15 mmol) of tris(2-methylphenyl)phosphine were added, and the mixture was heated and stirred at 100 °C under a nitrogen atmosphere for 6 hours to carry out the reaction.

[0485] After the reaction, 500 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:4) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and hexane was added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 5.4 g of the target substance as a white powder, with a yield of 82%. The reaction scheme of Step 2 is shown in (F6-2).

[54]

[0487]

[0488] The Rf values of the target substance and 3-bromo-9-(1-naphthyl)-9H-carbazole were 0.25 and 0.53, respectively, and these measured values were obtained by silica gel thin-layer chromatography (TLC) (the elution solvent contained ethyl acetate and hexane in a ratio of 1:10).

[0489] The obtained compound was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0490] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.04 (dd, J = 6.3 Hz, 1.5 Hz, 1H), 7.11 (d, J = 8.4 Hz, 1H), 7.30 - 7.70 (m, 14H), 7.83 - 7.94 (m, 4H), 8.02 - 8.07 (m, 3H), 8.28 (dd, J = 6.3 Hz, 2.4 Hz, 1H), 8.52 (d, J = 1.5 Hz, 1H).

[0491] Figure 23A and 23B is 1 the ¹H NMR spectrum. It should be noted that Figure 23B is Figure 23A an enlarged view in the range of 6.0 ppm to 9.0 ppm. The test results confirm that the target substance NCPN can be obtained.

[0492] Figure 24A shows the absorption spectrum of NCPN in a toluene solution of NCPN, Figure 24B showing its emission spectrum. Figure 25A shows the absorption spectrum of the NCPN film, Figure 25B showing its emission spectrum. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics). Measurements were made on samples prepared as follows: The solution was placed in a quartz cell, and a film was obtained on a quartz substrate by evaporation. Figure 24A shows the absorption spectrum of NCPN in the NCPN solution, obtained by subtracting the absorption spectra of the quartz cell and the toluene placed therein. Figure 25A shows the absorption spectrum of the film, obtained by subtracting the absorption spectrum of the quartz substrate. In Figure 24A and 24B and Figure 25A and 25B the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary unit). For the case of the toluene solution, an absorption peak was observed at approximately 300 nm, and the maximum emission wavelength was 388 nm (excitation wavelength: 300 nm). For the case of the film, an absorption peak was observed at approximately 322 nm, and the maximum emission wavelength was 397 nm (excitation wavelength: 328 nm).

[0493] The absorption spectrum shows that the NCPN described in this example is a material with weak absorption of light in the visible range. In addition, the emission spectrum shows that NCPN exhibits blue-violet light emission.

[0494] [Example 7]

[0495] In this example, an example of preparing 3,6-di-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: NP2PC) represented by the structural formula (112) in Preparation Method 1 will be described.

[55]

[0497]

[0498] In a 200 mL three-necked flask, a mixture of 2.0 g (5.0 mmol) of 3,6-dibromo-9-phenyl-9H-carbazole, 2.7 g (11 mmol) of 4-(1-naphthyl)phenylboronic acid, 100 mg (0.5 mmol) of palladium(II) acetate, 41 mg (0.1 mmol) of tris(o-tolyl)phosphine, 20 mL of toluene, 2 mL of ethanol, and 30 mL of aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 85 °C for 13 hours under a nitrogen atmosphere to carry out the reaction.

[0499] After the reaction, 150 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:4) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and acetone and methanol were added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 2.2 g of a white powdery target substance with a yield of 69%. The reaction scheme of this method is shown in (F7-1).

[56]

[0501]

[0502] The Rf values of the target substance and 3,6-dibromo-9-phenyl-9H-carbazole were 0.25 and 0.58, respectively, and these measured values were obtained by silica gel thin layer chromatography (TLC) (the elution solvent contained ethyl acetate and hexane in a ratio of 1:10).

[0503] The obtained compound was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0504] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.45 - 7.68 (m, 19H), 8.02 (dd, J = 2.1 Hz, 9.0 Hz, 2H), 7.87 - 7.95 (m, 8H), 8.05 (d, J = 7.8 Hz, 2H), 8.55 (d, J = 1.5 Hz, 2H).

[0505] Figure 26A and 26B is 1 the H NMR spectrum. It should be noted that Figure 26B is Figure 26A an enlarged view in the range of 7.0 ppm to 9.0 ppm. The test results confirmed that the target substance NP2PC could be obtained.

[0506] Figure 27A Show the absorption spectrum of NP2PC in a toluene solution of NP2PC, Figure 27B and show its emission spectrum. Figure 28A Show the absorption spectrum of the NP2PC film, Figure 28B and show its emission spectrum. The absorption spectrum was measured using a UV-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics). The measurements were performed on samples prepared as follows: The solution was placed in a quartz cell, and the film was obtained on a quartz substrate by evaporation. Figure 27A Show the absorption spectrum of NP2PC in the NP2PC solution, obtained by subtracting the absorption spectra of the quartz cell and the toluene placed therein. Figure 28A Show the absorption spectrum of the film, obtained by subtracting the absorption spectrum of the quartz substrate. In Figure 27A and 27B as well as Figure 28A and 28B and

[0507] The absorption spectrum shows that the NP2PC described in this example is a material that weakly absorbs light in the visible range. Additionally, the emission spectrum shows that NP2PC exhibits emission of blue-violet light.

[0508] Furthermore, its thermophysical properties were detected using a differential scanning calorimeter (DSC). The measurement results showed that the melting point was 269 °C. Additionally, no glass transition and crystallization peaks were observed; thus, it was found that NP2PC is a substance that is difficult to crystallize.

[0509] [Example 8]

[0510] In this example, the measurement results of the highest occupied molecular orbital (HOMO) energy level, the lowest unoccupied molecular orbital (LUMO) energy level, and the bandgap (Bg) of each carbazole compound synthesized in Examples 1, 2, and 4 - 7 according to an embodiment of the present invention in the film state will be described.

[0511] It should be noted that the tests conducted in this embodiment are as described below. The ionization potential value measured in air using a photoelectron spectrometer (AC-2, manufactured by Riken Keiki Co., Ltd.) is converted to a negative value to obtain the HOMO energy level value. The LUMO energy level value is obtained as follows: Assuming direct transition, using the data on the absorption spectrum of the thin film described in each embodiment, the absorption edge is obtained from the Tauc curve, and this absorption edge is regarded as the optical energy gap and added to the HOMO energy level value.

[0512] Table 1 shows the HOMO energy levels and LUMO energy levels of PCPN, PCPPn, mPCPPn, mPCzPTp, NCPN, and NP2PC obtained through this test.

[0513] [Table 1]

[0514] Abbreviation HOMO energy level LUMO energy level Band gap PCPN -5.77 -2.29 3.48 PCPPn -5.78 -2.25 3.53 mPCPPn -5.69 -2.37 3.32 mPCzPTp -5.70 -2.41 3.29 NCPN -5.83 -2.37 3.46 NP2PC -5.74 -2.36 3.38

[0515] Table 1 confirms that various carbazole compounds PCPN, PCPPn, mPCPPn, mPCzPTp, NCPN, and NP2PC according to an embodiment of the present invention have relatively deep HOMO energy levels, shallow LUMO energy levels, and wide band gaps.

[0516] [Example 9]

[0517] In this embodiment, various manufacturing methods of the light-emitting elements each constituting an embodiment of the present invention, the test results of the element characteristics, and the test results of the comparative light-emitting elements will be described.

[0518] Hereinafter, reference will be made to Figure 29 Describe the manufacturing methods of the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1. In addition, the structural formulas of the organic compounds used in this embodiment are as shown below.

[57]

[0520]

[0521] (Light-emitting element 1)

[0522] First, indium tin oxide containing silicon oxide (ITSO) is deposited on the glass substrate 1100 by sputtering to form the first electrode 1101. The thickness of the first electrode 1101 is 110 nanometers. The electrode area is 2 mm × 2 mm. In this embodiment, the first electrode 1101 is used as the anode.

[0523] Then, the substrate 1100 provided with the first electrode 1101 is fixed to the substrate jig of the vacuum evaporation equipment, with the surface where the first electrode 1101 is located facing downward. Then, the pressure of the vacuum evaporation equipment is reduced to about 10 -4Pa. Subsequently, 3-(4-(1-naphthyl)phenyl)-9-phenyl-9H-carbazole (abbreviation: PCPN) synthesized in Example 1 and molybdenum(VI) oxide were co-evaporated onto the first electrode 1101 to form a hole injection layer 1111. The thickness of the hole injection layer 1111 was 50 nm. The weight ratio of PCPN to molybdenum(VI) oxide was adjusted to 4:2 (= PCPN: molybdenum(VI) oxide). It should be noted that the co-evaporation method is a vapor deposition method in which vapor deposition is carried out simultaneously from multiple evaporation sources in one processing chamber.

[0524] Then, PCPN with a thickness of 10 nm was deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0525] In addition, by co-depositing 9-[4-(N-carbazolyl)phenyl]-10-phenylanthracene (abbreviation: CzPA) and N,N′-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-N,N′-diphenylpyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), a light-emitting layer 1113 was formed on the hole transport layer 1112. The weight ratio of CzPA to 1,6FLPAPrn was adjusted to 1:0.05 (= CzPA: 1,6FLPAPrn). The thickness of the light-emitting layer 113 was 30 nm.

[0526] Then, CzPA with a thickness of 10 nm was deposited on the light-emitting layer 1113 to form a first electron transport layer 1114a.

[0527] Then, bathophenanthroline (abbreviation: BPhen) with a thickness of 15 nm was deposited on the first electron transport layer 1114a to form a second electron transport layer 1114b.

[0528] In addition, a lithium fluoride (LiF) film with a thickness of 1 nm was formed on the second electron transport layer 1114b by evaporation to form an electron injection layer 1115.

[0529] Finally, an aluminum film with a thickness of 200 nm was formed by an evaporation method to form a second electrode 1103, and the function of this electrode was to act as a cathode. Thus, the light-emitting element 1 of this embodiment was fabricated.

[0530] It should be noted that in the above evaporation process, the resistance heating method was used for evaporation.

[0531] (Light-emitting element 2)

[0532] The light-emitting element 2 was formed in a similar manner to the light-emitting element 1 except for the hole injection layer 1111 and the hole transport layer 1112.

[0533] In the light-emitting element 2, 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn) synthesized in Example 2 and molybdenum(VI) oxide were co-evaporated on the first electrode 1101 to form a hole injection layer 1111. The thickness of the hole injection layer 1111 was 50 nm. The weight ratio of PCPPn to molybdenum(VI) oxide was adjusted to 4:2 (= PCPPn: molybdenum oxide).

[0534] Then, PCPPn with a thickness of 10 nm was deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0535] (Comparative light-emitting element 1)

[0536] Comparative light-emitting element 1 was formed in a manner similar to that of light-emitting element 1, except for the hole injection layer 1111 and the hole transport layer 1112.

[0537] In Comparative light-emitting element 1, 9-[4-(9-phenylcarbazol-3-yl)phenyl]-10-phenylanthracene (abbreviation: PCzPA) and molybdenum(VI) oxide were co-evaporated on the first electrode 1101 to form a hole injection layer 1111. The thickness of the hole injection layer 1111 was 50 nm. The weight ratio of PCzPA to molybdenum(VI) oxide was adjusted to 4:2 (= PCzPA: molybdenum oxide).

[0538] Then, PCzPA with a thickness of 10 nm was deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0539] Table 2 shows the element structures of the above-prepared light-emitting element 1, light-emitting element 2, and Comparative light-emitting element 1.

[0540] [Table 2]

[0541]

[0542]

[0543] *All mixing ratios are expressed as weight ratios.

[0544] The light-emitting element 1, light-emitting element 2, and Comparative light-emitting element 1 were sealed in a glove box with a nitrogen atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was carried out at room temperature (the atmosphere was maintained at 25 °C).

[0545] It should be noted that the light-emitting element 1, light-emitting element 2, and Comparative light-emitting element 1 were formed on the same substrate. In addition, among the above three light-emitting elements, except for the hole injection layer and the hole transport layer, each component was formed simultaneously, and the operating characteristics of the three light-emitting elements were measured simultaneously.

[0546] Table 3 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1 at a luminance of about 1000 cd / m 2 respectively.

[0547] [Table 3]

[0548]

[0549] Figure 30 shows the emission spectra of the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1. In Figure 30 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 31 , Figure 32 and Figure 33 show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1 respectively. In Figure 31 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 32 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In Figure 33 , the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0550] As Figure 30 shows, the emission spectra of the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1 all have peaks at around 470 nm. The CIE color coordinates in Table 3 also show that the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1 exhibit blue light emission derived from 1,6FLPAPrn, and all the elements have good carrier balance.

[0551] In addition, Figures 31 - 33 and Table 3 show that the light-emitting element 1 and the light-emitting element 2 can be driven at the same low voltage as the comparative light-emitting element 1, and the efficiencies of the light-emitting element 1 and the light-emitting element 2 are higher than those of the comparative light-emitting element 1.

[0552] The reasons for the above phenomena may be as follows. The bandgap of PCzPA used in the light-emitting element 1 is 2.92 eV. When PCzPA used for the hole transport layer contacts the light-emitting layer, energy transfer from the light-emitting layer (exciton transfer generated in the light-emitting layer) occurs. On the contrary, in this embodiment, the bandgaps of PCPN used for the hole injection layer and the hole transport layer in the light-emitting element 1 and PCPPn used for the hole injection layer and the hole transport layer in the light-emitting element 2 are large, being 3.48 eV and 3.53 eV respectively, which hinders the occurrence of energy transfer in the light-emitting layer.

[0553] The LUMO energy level of PCzPA is -2.77 eV, and carrier loss may occur due to electron leakage in the light-emitting layer. On the contrary, the LUMO energy levels of PCPN and PCPPn are shallow, being -2.29 eV and -2.25 eV respectively, which can prevent the occurrence of electron leakage in each light-emitting layer. Therefore, the light-emitting element 1 and the light-emitting element 2 can achieve high efficiency. In addition, the HOMO energy level of PCzPA is -5.69 eV, which is close to the HOMO energy level of -5.70 eV of the host material CzPA adjacent to the light-emitting layer; thus, excellent hole injection performance is obtained. At the same time, the HOMO energy levels of PCPN and PCPPn are deep, being -5.77 eV and -5.78 eV respectively; thus, excellent hole injection performance is obtained. In addition, both the light-emitting element 1 and the light-emitting element 2 can be driven at the same low voltage as the comparative light-emitting element 1, and thus have excellent carrier transport ability.

[0554] Note that PCzPA is a material with good hole transport properties and long lifetime.

[0555] In addition, reliability tests were performed on the fabricated light-emitting element 1, light-emitting element 2, and comparative light-emitting element 1. In the reliability test, the initial brightness was set to 5000 cd / m2, and these elements were driven under the condition of a constant current density, and the brightness was measured at regular intervals. The results of the reliability test are shown in Figure 34 In Figure 34 the horizontal axis represents the current time (hours), and the vertical axis represents the ratio of the brightness at each time point to the initial brightness, that is, the normalized brightness (%).

[0556] According to Figure 34 , the light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1 are all not prone to brightness reduction over time, and each element has a long lifetime. The light-emitting element 1, the light-emitting element 2, and the comparative light-emitting element 1 still maintain 52% of the initial brightness even after working for 210 hours.

[0557] As described above, the carbazole compound according to an embodiment of the present invention is used for a hole injection layer and a hole transport layer, thereby obtaining an element having high emission efficiency. The reason for the above phenomenon may be as follows: The LUMO energy level of the carbazole compound according to an embodiment of the present invention is shallow enough to suppress the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its band gap is wide enough to suppress the efficiency reduction caused by the exciton energy transfer.

[0558] It is also shown that when the carbazole compound according to an embodiment of the present invention is used for a hole injection layer and a hole transport layer, a light-emitting element having a low driving voltage can be produced.

[0559] It is also shown that when the carbazole compound according to an embodiment of the present invention is used for a hole injection layer and a hole transport layer, a light-emitting element having a long lifetime can be produced.

[0560] [Example 10]

[0561] In this embodiment, various manufacturing methods of the light-emitting elements each constituting an embodiment of the present invention and the test results of the element characteristics, as well as the test results of the comparative light-emitting elements, will be described.

[0562] The manufacturing methods of the light-emitting element 3, the light-emitting element 4, and the comparative light-emitting element 2 will be described below. It should be noted that the element structure of the light-emitting element obtained in this embodiment is similar to Figure 29 the structure shown. In addition, the organic compounds used in this embodiment are similar to those in Example 9; therefore, the description of the organic compounds is omitted.

[0563] (Light-emitting element 3)

[0564] The light-emitting element 3 is manufactured in a similar manner to the light-emitting element 1 in Example 9, except for the hole injection layer 1111 and the hole transport layer 1112.

[0565] In the light-emitting element 3, a molybdenum(VI) oxide film having a thickness of 10 nm is formed on the first electrode 1101 by evaporation to form the hole injection layer 1111.

[0566] Then, the PCPN synthesized in Example 1 having a thickness of 30 nm is deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0567] (Light-emitting element 4)

[0568] The light-emitting element 4 is manufactured in a similar manner to the light-emitting element 3, except for the hole transport layer 1112.

[0569] In the light-emitting element 4, the PCPPn synthesized in Example 2 having a thickness of 30 nm is deposited to form the hole transport layer 1112.

[0570] (Comparative Light-Emitting Element 2)

[0571] The Comparative Light-Emitting Element 2 is fabricated in a manner similar to that of the Light-Emitting Element 3, except for the hole transport layer 1112.

[0572] In the Comparative Light-Emitting Element 2, PCzPA with a thickness of 30 nm is deposited to form the hole transport layer 1112.

[0573] Table 4 shows the element structures of the Light-Emitting Element 3, the Light-Emitting Element 4, and the Comparative Light-Emitting Element 2 fabricated above.

[0574] [Table 4]

[0575]

[0576] *All mixing ratios are expressed as weight ratios.

[0577] The Light-Emitting Element 3, the Light-Emitting Element 4, and the Comparative Light-Emitting Element 2 are sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements are measured. Note that the measurement is carried out at room temperature (the atmosphere is maintained at 25 °C).

[0578] It should be noted that the Light-Emitting Element 3, the Light-Emitting Element 4, and the Comparative Light-Emitting Element 2 are formed on the same substrate. In addition, among the above three light-emitting elements, except for the hole transport layer, each component is formed simultaneously, and the operating characteristics of the three light-emitting elements are measured simultaneously.

[0579] Table 5 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the Light-Emitting Element 3, the Light-Emitting Element 4, and the Comparative Light-Emitting Element 2 at a luminance of approximately 1000 cd / m 2 .

[0580] [Table 5]

[0581]

[0582]

[0583] Figure 35 shows the emission spectra of the Light-Emitting Element 3, the Light-Emitting Element 4, and the Comparative Light-Emitting Element 2. In Figure 35 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 36 , Figure 37 and Figure 38The voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting element 3, the light-emitting element 4, and the comparative light-emitting element 2 are respectively shown. In Figure 36 , the vertical axis represents luminance (cd / m 2 ), and the horizontal axis represents voltage (V). In Figure 37 , the vertical axis represents current efficiency (cd / A), and the horizontal axis represents luminance (cd / m 2 ). In Figure 38 , the vertical axis represents power efficiency (lm / W), and the horizontal axis represents luminance (cd / m 2 ).

[0584] As Figure 35 shows, the emission spectra of the light-emitting element 3, the light-emitting element 4, and the comparative light-emitting element 2 all have peaks at around 470 nm. The CIE color coordinates in Table 5 also show that the light-emitting element 3, the light-emitting element 4, and the comparative light-emitting element 2 exhibit blue light emission derived from 1,6FLPAPrn, and all the elements have good carrier balance.

[0585] In addition, Figure 36 , Figure 37 , Figure 38 , and Table 5 show that the efficiencies of the light-emitting element 3 and the light-emitting element 4 are higher than those of the comparative light-emitting element 2. The reasons for the above phenomena may be as follows: In this embodiment, the band gaps of PCPN used for the hole transport layer of the light-emitting element 3 and PCPPn used for the hole transport layer of the light-emitting element 4 are wider than the band gap of PCzPA used for the comparative light-emitting element 2; energy transfer in the light-emitting layer is not likely to occur; the LUMO energy levels of PCPN and PCPPn are low enough to suppress electron leakage.

[0586] In addition, reliability tests are performed on the fabricated light-emitting element 3, light-emitting element 4, and comparative light-emitting element 2. In the reliability test, the initial luminance is set to 5000 cd / m 2 , and these elements are operated under the condition of constant current density, and the luminance is measured at regular intervals. The results of the reliability test are shown in Figure 39 . In Figure 39 , the horizontal axis represents current time (hours), and the vertical axis represents the ratio of the luminance at each time point to the initial luminance, that is, the normalized luminance (%).

[0587] According to Figure 39 , the light-emitting element 3, the light-emitting element 4, and the comparative light-emitting element 2 are all not likely to have a decrease in luminance over time, and the lifetimes of the respective elements are long. The light-emitting element 3, the light-emitting element 4, and the comparative light-emitting element 2 still maintain 60%, 56%, and 54% of the initial luminance even after being driven for 150 hours.

[0588] In this embodiment, a monolayer film of molybdenum oxide is used for the hole injection layer. The driving voltage of all components in this embodiment is slightly higher than that in Embodiment 9, in which a mixed material of a carbazole compound and molybdenum oxide according to an embodiment of the present invention is used for the hole injection layer. This indicates that when a mixed material of a carbazole compound and molybdenum oxide according to an embodiment of the present invention is used for the hole injection layer, an element with excellent hole injection properties can be obtained.

[0589] As described above, a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, thereby obtaining an element with high emission efficiency. The reasons for the above phenomena may be as follows: the LUMO energy level of a carbazole compound according to an embodiment of the present invention is shallow enough to inhibit the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its bandgap is wide enough to inhibit the efficiency reduction caused by exciton energy transfer.

[0590] It is also shown that when a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a long lifetime can be obtained.

[0591] It is also shown that good performance can be obtained even in a light-emitting element in which a hole injection layer is formed of a single layer of molybdenum oxide. It should be noted that the hole injection layer is preferably formed of a composite material, and in this case, short circuit of the light-emitting element due to the quality of the anode film can be prevented.

[0592] [Embodiment 11]

[0593] In this embodiment, the manufacturing method of a light-emitting element according to an embodiment of the present invention and the test results of the element characteristics, as well as the test results of the comparative light-emitting element, will be described.

[0594] The manufacturing methods of the light-emitting element 5 and the comparative light-emitting element 3 will be described below. It should be noted that the element structure of the light-emitting element obtained in this embodiment is similar to the structure Figure 29 shown. In addition, the organic compounds used in this embodiment are similar to those in Embodiment 9; therefore, the description of the organic compounds is omitted.

[0595] (Light-emitting element 5)

[0596] The light-emitting element 5 is manufactured in a similar manner to the light-emitting element 1 in Embodiment 9, except for the hole injection layer 1111 and the hole transport layer 1112.

[0597] In the light-emitting element 5, 9-(1-naphthyl)-3-[4-(1-naphthyl)phenyl]-9H-carbazole (abbreviation: NCPN) synthesized in Example 6 and molybdenum(VI) oxide were co-evaporated on the first electrode 1101 to form a hole injection layer 1111. The thickness of the hole injection layer 1111 was 50 nm. The weight ratio of NCPN to molybdenum(VI) oxide was adjusted to 4:2 (= NCPN: molybdenum(VI) oxide).

[0598] Then, NCPN with a thickness of 10 nm was deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0599] (Comparative light-emitting element 3)

[0600] Comparative light-emitting element 3 was fabricated in a manner similar to that of Comparative light-emitting element 1 in Example 9.

[0601] Table 6 shows the element structures of the light-emitting element 5 and Comparative light-emitting element 3 obtained as described above.

[0602] [Table 6]

[0603]

[0604]

[0605] *All mixing ratios are expressed as weight ratios.

[0606] The light-emitting element 5 and Comparative light-emitting element 3 were sealed in a glove box with a nitrogen atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was carried out at room temperature (the atmosphere was maintained at 25 °C).

[0607] It should be noted that the light-emitting element 5 and Comparative light-emitting element 3 were formed on the same substrate. In addition, in the above two light-emitting elements, except for the hole injection layer and the hole transport layer, each component was formed simultaneously, and the operating characteristics of the two light-emitting elements were measured simultaneously.

[0608] Table 7 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 5 and Comparative light-emitting element 3 at a luminance of approximately 1000 cd / m 2 .

[0609] [Table 7]

[0610]

[0611] Figure 40The emission spectra of the light-emitting element 5 and the comparative light-emitting element 3 are shown. In Figure 40 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 41 , Figure 42 and Figure 43 show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting element 5 and the comparative light-emitting element 3, respectively. In Figure 41 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 42 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In Figure 43 , the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0612] As Figure 40 shows, both the emission spectra of the light-emitting element 5 and the comparative light-emitting element 3 have peaks at around 470 nm. The CIE color coordinates in Table 7 also show that the light-emitting element 5 and the comparative light-emitting element 3 exhibit blue light emission derived from 1,6FLPAPrn, and all the elements have good carrier balance.

[0613] In addition, Figure 41 , Figure 42 , Figure 43 and Table 7 show that the efficiency of the light-emitting element 5 is higher than that of the comparative light-emitting element 3. The reasons for the above phenomena may be as follows: In this embodiment, the bandgap of NCPN in the hole injection layer and the hole transport layer for the light-emitting element 5 is wider than the bandgap of PCzPA for the comparative light-emitting element 3; energy transfer in the light-emitting layer is not likely to occur; the LUMO energy level of NCPN is shallow enough to prevent electrons from passing through the light-emitting layer.

[0614] In addition, Figures 41 - 43 and Table 7 show that the light-emitting element 5 and the comparative light-emitting element 3 can be driven at low voltages.

[0615] In addition, the fabricated light-emitting element 5 and the comparative light-emitting element 3 are subjected to a reliability test. In the reliability test, the initial luminance is set to 5000 cd / m 2 , and these elements are operated under the condition of a constant current density, and the luminance is measured at regular intervals. The results of the reliability test are shown in Figure 44 . In Figure 44 , the horizontal axis represents the current time (hours), and the vertical axis represents the ratio of the luminance at each time point to the initial luminance, i.e., the normalized luminance (%).

[0616] According to Figure 44, both the light-emitting element 5 and the comparative light-emitting element 3 are not prone to brightness reduction over time, and each element has a long lifespan. Even after being driven for 130 hours, the light-emitting element 5 and the comparative light-emitting element 3 still maintain 62% and 57% of their initial brightness respectively.

[0617] As described above, the carbazole compound of one embodiment of the present invention is used in the hole injection layer and the hole transport layer, thereby obtaining an element with high emission efficiency. The reasons for the above phenomena may be as follows: The LUMO energy level of the carbazole compound of one embodiment of the present invention is shallow enough to inhibit the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its bandgap is wide enough to inhibit the efficiency reduction caused by exciton energy transfer.

[0618] In addition, it is shown that when the carbazole compound of one embodiment of the present invention is used in the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be obtained.

[0619] In addition, it is also shown that when the carbazole compound of one embodiment of the present invention is used in the hole injection layer and the hole transport layer, a light-emitting element with a long lifespan can be obtained.

[0620] [Example 12]

[0621] In this example, the manufacturing method of the light-emitting element constituting one embodiment of the present invention, the test results of the element characteristics, and the test results of the comparative light-emitting element will be described.

[0622] The manufacturing methods of the light-emitting element 6 and the comparative light-emitting element 4 will be described below. It should be noted that the element structure of the light-emitting element obtained in this example is similar to the Figure 29 structure shown. In addition, the organic compounds used in this example are similar to those in Example 9; therefore, the description of the organic compounds is omitted.

[0623] (Light-emitting element 6)

[0624] The light-emitting element 6 is fabricated in a similar manner to the light-emitting element 1 in Example 9, except for the hole injection layer 1111 and the hole transport layer 1112.

[0625] In the light-emitting element 6, 3,6-di-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: NP2PC) synthesized in Example 7 and molybdenum(VI) oxide are co-evaporated on the first electrode 1101 to form the hole injection layer 1111. The thickness of the hole injection layer 1111 is 50 nm. The weight ratio of NP2PC to molybdenum(VI) oxide is adjusted to 4:2 (=NP2PC:molybdenum oxide).

[0626] Then, NP2PC with a thickness of 10 nm was deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0627] (Comparative light-emitting element 4)

[0628] Comparative light-emitting element 4 was fabricated in a manner similar to that of comparative light-emitting element 1 in Example 9.

[0629] Table 8 shows the element structures of the light-emitting element 6 and comparative light-emitting element 4 obtained as described above.

[0630] [Table 8]

[0631]

[0632] *All mixing ratios are expressed as weight ratios.

[0633] The light-emitting element 6 and comparative light-emitting element 4 were sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was carried out at room temperature (the atmosphere was maintained at 25 °C).

[0634] It should be noted that the light-emitting element 6 and comparative light-emitting element 4 were formed on the same substrate. In addition, among the above two light-emitting elements, except for the hole injection layer and hole transport layer, each component was formed simultaneously, and the operating characteristics of the two light-emitting elements were measured simultaneously.

[0635] Table 9 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), brightness (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 6 and comparative light-emitting element 4 at a brightness of approximately 1000 cd / m 2 .

[0636] [Table 9]

[0637]

[0638] Figure 45 shows the emission spectra of the light-emitting element 6 and comparative light-emitting element 4. In Figure 45 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 46 , Figure 47 and Figure 48 show the voltage-brightness characteristics, brightness-current efficiency characteristics, and brightness-power efficiency characteristics of the light-emitting element 6 and comparative light-emitting element 4, respectively. In Figure 46 , the vertical axis represents the brightness (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 47In [Figure 0], the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In Figure 48 [Figure 1], the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0639] As Figure 45 shown, both the emission spectra of the light-emitting element 6 and the comparative light-emitting element 4 have peaks at around 470 nm. The CIE color coordinates in Table 9 also show that the light-emitting element 6 and the comparative light-emitting element 4 exhibit blue light emission derived from 1,6FLPAPrn, and all the elements have good carrier balance.

[0640] In addition, Figure 46 , Figure 47 , Figure 48 and Table 9 show that the efficiency of the light-emitting element 6 is higher than that of the comparative light-emitting element 4. The reasons for the above phenomena may be as follows: In this embodiment, the bandgap of NP2PC for the hole injection layer and the hole transport layer of the light-emitting element 6 is wider than the bandgap of PCzPA for the comparative light-emitting element 4; energy transfer in the light-emitting layer is not likely to occur; the LUMO energy level of NP2PC is shallow enough to prevent electrons from passing through the light-emitting layer.

[0641] In addition, Figures 46 - 48 and Table 9 show that the light-emitting element 6 and the comparative light-emitting element 4 can be driven at a low voltage.

[0642] In addition, reliability tests were performed on the fabricated light-emitting element 6 and the comparative light-emitting element 4. In the reliability test, the initial luminance was set to 5000 cd / m2, and these elements were operated under the condition of a constant current density, and the luminance was measured at regular intervals. The results of the reliability test are shown in Figure 49 [Figure 2]. In Figure 49 [Figure 2], the horizontal axis represents the current time (hours), and the vertical axis represents the ratio of the luminance at each time point to the initial luminance, that is, the normalized luminance (%).

[0643] According to Figure 49 [Figure 2], neither the light-emitting element 6 nor the comparative light-emitting element 4 is likely to experience a decrease in luminance over time, and the lifetime of each element is long. The light-emitting element 6 and the comparative light-emitting element 4 still maintain 63% and 57% of the initial luminance even after being driven for 130 hours.

[0644] As described above, a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, thereby fabricating an element with high emission efficiency. The reasons for the above phenomena may be as follows: The LUMO energy level of the carbazole compound according to an embodiment of the present invention is shallow enough to inhibit the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its bandgap is wide enough to inhibit the efficiency reduction caused by exciton energy transfer.

[0645] It is also shown that when the carbazole compound of an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be produced.

[0646] It is also shown that when the carbazole compound of an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a long lifespan can be produced.

[0647] [Example 13]

[0648] In this example, the manufacturing method of the light-emitting element constituting an embodiment of the present invention and the test results of the element characteristics, as well as the test results of the comparative light-emitting element, will be described.

[0649] The manufacturing methods of the light-emitting element 7 and the comparative light-emitting element 5 will be described below. It should be noted that the element structure of the light-emitting element obtained in this example is similar to ​ the structure shown. In addition, the organic compounds used in this example are similar to those in Example 9; therefore, the description of the organic compounds is omitted.

[0650] (Light-emitting element 7)

[0651] The light-emitting element 7 is fabricated in a similar manner to the light-emitting element 1 in Example 9, except for the hole injection layer 1111 and the hole transport layer 1112.

[0652] In the light-emitting element 7, 3-[3-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: mPCPPn) synthesized in Example 4 and molybdenum(VI) oxide are co-evaporated on the first electrode 1101 to form the hole injection layer 1111. The thickness of the hole injection layer 1111 is 50 nm. The weight ratio of mPCPPn to molybdenum(VI) oxide is adjusted to 4:2 (= mPCPPn: molybdenum oxide).

[0653] Then, mPCPPn with a thickness of 10 nm is deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0654] (Comparative light-emitting element 5)

[0655] The comparative light-emitting element 5 is fabricated in a similar manner to the comparative light-emitting element 1 in Example 9.

[0656] Table 10 shows the element structures of the light-emitting element 7 and the comparative light-emitting element 5 obtained as described above.

[0657] [Table 10]

[0658]

[0659] *All mixing ratios are by weight.

[0660] The light-emitting element 7 and the comparative light-emitting element 5 were sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was carried out at room temperature (the atmosphere was maintained at 25 °C).

[0661] It should be noted that the light-emitting element 7 and the comparative light-emitting element 5 were formed on the same substrate. In addition, among the above two light-emitting elements, except for the hole injection layer and the hole transport layer, each component was formed simultaneously, and the operating characteristics of the two light-emitting elements were measured simultaneously.

[0662] Table 11 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 7 and the comparative light-emitting element 5 at a luminance of approximately 1000 cd / m 2 ).

[0663] [Table 11]

[0664]

[0665]

[0666] ​ shows the emission spectra of the light-emitting element 7 and the comparative light-emitting element 5. In ​ , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). ​ , ​ and ​ show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting element 7 and the comparative light-emitting element 5, respectively. In ​ , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In ​ , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In ​ , the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0667] As ​ shows, both the emission spectra of the light-emitting element 7 and the comparative light-emitting element 5 have peaks at around 470 nm. The CIE color coordinates in Table 11 also show that the light-emitting element 7 and the comparative light-emitting element 5 exhibit blue light emission originating from 1,6FLPAPrn, and all the elements have good carrier balance.

[0668] In addition, ​ , ​ and Table 7 show that the efficiency of the light-emitting element 7 is higher than that of the comparative light-emitting element 5. The reasons for the above phenomenon may be as follows: In this embodiment, the band gap of mPCPPn in the hole injection layer and the hole transport layer for the light-emitting element 7 is wider than that of PCzPA for the comparative light-emitting element 5; energy transfer in the light-emitting layer is not likely to occur; the LUMO energy level of mPCPPn is shallow enough to prevent electrons from passing through the light-emitting layer.

[0669] In addition, ​ , ​ , ​ and Table 11 show that the light-emitting element 7 and the comparative light-emitting element 5 can be driven at a low voltage.

[0670] As described above, a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, thereby obtaining an element with high emission efficiency. The reasons for the above phenomenon may be as follows: The LUMO energy level of the carbazole compound according to an embodiment of the present invention is shallow enough to suppress the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its band gap is wide enough to suppress the efficiency reduction caused by exciton energy transfer.

[0671] It is also shown that when a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be obtained.

[0672] [Example 14]

[0673] In this embodiment, the manufacturing method of the light-emitting element constituting an embodiment of the present invention and the test results of the element characteristics, as well as the test results of the comparative light-emitting element, will be described.

[0674] The manufacturing methods of the light-emitting element 8 and the comparative light-emitting element 6 will be described below. It should be noted that the element structure of the light-emitting element obtained in this embodiment is similar to the structure ​ shown. The structural formulas of the organic compounds used in this embodiment are as follows. It should be noted that the organic compounds whose structural formulas have been shown are omitted.

[58]

[0676]

[0677] (Light-emitting element 8)

[0678] The light-emitting element 8 is manufactured in a similar manner to the light-emitting element 7 in Example 13, except for the first electron transport layer 1114a.

[0679] In the light-emitting element 8, tris(8-hydroxyquinoline)aluminum(III) (abbreviation: Alq) is deposited on the light-emitting layer 1113 to a thickness of 10 nm to form a first electron transport layer 1114a.

[0680] (Comparative light-emitting element 6)

[0681] The comparative light-emitting element 6 is fabricated in a manner similar to that of the comparative light-emitting element 1 in Example 9, except for the first electron transport layer 1114a.

[0682] In the light-emitting element 6, Alq is deposited on the light-emitting layer 1113 to a thickness of 10 nm to form a first electron transport layer 1114a.

[0683] Table 12 shows the element structures of the light-emitting element 8 and the comparative light-emitting element 6 obtained as described above.

[0684] [Table 12]

[0685]

[0686]

[0687] *All mixing ratios are expressed as weight ratios.

[0688] The light-emitting element 8 and the comparative light-emitting element 6 are sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements are measured. Note that the measurement is performed at room temperature (the atmosphere is maintained at 25 °C).

[0689] It should be noted that the light-emitting element 8 and the comparative light-emitting element 6 are formed on the same substrate. In addition, in the above two light-emitting elements, except for the hole injection layer and the hole transport layer, each component is formed simultaneously, and the operating characteristics of the two light-emitting elements are measured simultaneously.

[0690] Table 13 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), brightness (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 8 and the comparative light-emitting element 6 at a brightness of approximately 1000 cd / m 2 .

[0691] [Table 13]

[0692]

[0693] ​ Shows the emission spectra of the light-emitting element 8 and the comparative light-emitting element 6. In ​ , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit).Figure 55 , Figure 56 and Figure 57 respectively show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting element 8 and the comparative light-emitting element 6. In Figure 55 , the vertical axis represents luminance (cd / m 2 ), and the horizontal axis represents voltage (V). In Figure 56 , the vertical axis represents current efficiency (cd / A), and the horizontal axis represents luminance (cd / m 2 ). In Figure 57 , the vertical axis represents power efficiency (lm / W), and the horizontal axis represents luminance (cd / m 2 ).

[0694] As Figure 54 shown, both the light-emitting element 8 and the comparative light-emitting element 6 have peaks at around 470 nm in their emission spectra. The CIE color coordinates in Table 13 also show that the light-emitting element 8 and the comparative light-emitting element 6 exhibit blue light emission derived from 1,6FLPAPrn, and all the elements have good carrier balance.

[0695] In addition, Figure 55 , Figure 56 , Figure 57 and Table 13 show that the efficiency of the light-emitting element 8 is higher than that of the comparative light-emitting element 6. The reasons for the above phenomena may be as follows: In this embodiment, the bandgap of mPCPPn in the hole injection layer and hole transport layer for the light-emitting element 8 is wider than the bandgap of PCzPA for the comparative light-emitting element 6; energy transfer in the light-emitting layer is not likely to occur; the LUMO energy level of mPCPPn is shallow enough to prevent electrons from passing through the light-emitting layer.

[0696] In addition, Figure 55 , Figure 56 and Table 13 show that the light-emitting element 8 and the comparative light-emitting element 6 can be driven at low voltages.

[0697] In addition, the fabricated light-emitting element 8 and comparative light-emitting element 6 are subjected to a reliability test. In the reliability test, the initial luminance is set to 5000 cd / m2, and these elements are operated under a constant current density condition, and the luminance is measured at regular intervals. The results of the reliability test are shown in Figure 58 . In Figure 58 , the horizontal axis represents current time (hours), and the vertical axis represents the ratio of the luminance at each time point to the initial luminance, that is, the normalized luminance (%).

[0698] According to Figure 58 , neither the light-emitting element 8 nor the comparative light-emitting element 6 is likely to experience a decrease in luminance over time, and the lifespan of each element is long. The light-emitting element 8 and the comparative light-emitting element 6 still maintain 83% and 81% of their initial luminance even after being driven for 70 hours.

[0699] As described above, the carbazole compound of an embodiment of the present invention is used for the hole injection layer and the hole transport layer, thereby fabricating an element with high emission efficiency. The reasons for the above phenomena may be as follows: The LUMO energy level of the carbazole compound of an embodiment of the present invention is shallow enough to suppress the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its bandgap is wide enough to suppress the efficiency reduction caused by the exciton energy transfer.

[0700] It is also shown that when the carbazole compound of an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be fabricated.

[0701] It is further shown that when the carbazole compound of an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a long lifespan can be fabricated.

[0702] [Example 15]

[0703] In this example, the manufacturing method of the light-emitting element constituting an embodiment of the present invention, the test results of the element characteristics, and the test results of the comparative light-emitting element will be described.

[0704] The manufacturing methods of the light-emitting element 9 and the comparative light-emitting element 7 will be described below. It should be noted that the element structure of the light-emitting element fabricated in this example is similar to Figure 29 the structure shown. The structural formulas of the organic compounds used in this example are shown below. It should be noted that the organic compounds whose structural formulas have been shown are omitted.

[59]

[0706]

[0707] (Light-emitting element 9)

[0708] The light-emitting element 9 is fabricated in a manner similar to that of the light-emitting element 1 in Example 9, except for the hole injection layer 1111, the hole transport layer 1112, the light-emitting layer 1113, and the first electron transport layer 1114a.

[0709] In the light-emitting element 9, 9-phenyl-3-[3-(benzo[9,10]phenanthren-2-yl)phenyl]-9H-carbazole (abbreviation: mPCzPTp) synthesized in Example 5 and molybdenum(VI) oxide are co-evaporated on the first electrode 1101 to form the hole injection layer 1111. The thickness of the hole injection layer 1111 is 50 nm. The weight ratio of mPCzPTp to molybdenum(VI) oxide is adjusted to 4:2 (= mPCzPTp: molybdenum(VI) oxide).

[0710] Then, mPCzPTp with a thickness of 10 nm was deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0711] In addition, 4-[3-(benzo[9,10]phenanthren-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II) and tris(2-phenylpyridine-N,C 2′ )iridium(III) (abbreviation: Ir(ppy)3) were co-evaporated on the hole transport layer 1112 to form the light-emitting layer 1113. The weight ratio of mDBTPTp-II to Ir(ppy)3 was adjusted to 1:0.06 (= mDBTPTp-II:Ir(ppy)3). The thickness of the light-emitting layer 113 was 40 nm.

[0712] Then, Alq with a thickness of 15 nm was deposited on the light-emitting layer 1113 to form the first electron transport layer 1114a.

[0713] (Comparative light-emitting element 7)

[0714] Comparative light-emitting element 7 was fabricated in a similar manner to Comparative light-emitting element 1 in Example 9, except for the light-emitting layer 1113 and the first electron transport layer 1114a.

[0715] In Comparative light-emitting element 7, the structures of the light-emitting layer 1113 and the first electron transport layer 1114a were similar to those of the above-described light-emitting element 9.

[0716] Table 14 shows the element structures of the light-emitting element 9 and the Comparative light-emitting element 7 obtained as described above.

[0717] [Table 14]

[0718]

[0719]

[0720] *All mixing ratios are expressed as weight ratios.

[0721] The light-emitting element 9 and the Comparative light-emitting element 7 were sealed in a glove box with a nitrogen atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was carried out at room temperature (the atmosphere was maintained at 25 °C).

[0722] It should be noted that the light-emitting element 9 and the Comparative light-emitting element 7 were formed on the same substrate. In addition, in the above two light-emitting elements, except for the hole injection layer and the hole transport layer, each component was formed simultaneously, and the operating characteristics of the two light-emitting elements were measured simultaneously.

[0723] Table 15 shows the light-emitting element 9 and the Comparative light-emitting element 7 at a brightness of approximately 1000 cd / m 2Voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) at

[0724] [Table 15]

[0725] Light-emitting element 9 Comparative light-emitting element 7 Voltage (V) 7.0 7.0 <![CDATA[Current density (mA / cm 2 )]]> 2.1 3.5 Color coordinates (x, y) (0.36,0.61) (0.36,0.61) <![CDATA[Brightness (cd / m 2 )]]> 990 910 Current efficiency (cd / A) 47 26 Power efficiency (lm / W) 21 12 External quantum efficiency (%) 14 8.0

[0726] Figure 59 The emission spectra of the light-emitting element 9 and the comparative light-emitting element 7 are shown. In Figure 59 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 60 and Figure 61 show the voltage-luminance characteristics and luminance-power efficiency characteristics of the light-emitting element 9 and the comparative light-emitting element 7, respectively. In Figure 60 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 61 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ).

[0727] As Figure 59 shown, both the emission spectra of the light-emitting element 9 and the comparative light-emitting element 7 have peaks around 520 nm. The CIE color coordinates in Table 15 also show that the light-emitting element 9 and the comparative light-emitting element 7 exhibit green phosphorescence emission from Ir(ppy)3, and all the elements have good carrier balance.

[0728] In addition, Figure 60 , Figure 61 and Table 15 show that the efficiency of the light-emitting element 9 is higher than that of the comparative light-emitting element 7. The reasons for the above phenomena may be as follows: In this embodiment, the bandgap of mPCzPTp for the hole injection layer and the hole transport layer of the light-emitting element 9 is wider than the bandgap of PCzPA for the comparative light-emitting element 7; energy transfer in the light-emitting layer is not likely to occur; the LUMO energy level of mPCzPTp is shallow enough to prevent electrons from passing through the light-emitting layer.

[0729] In addition, Figure 60 , Figure 61 and Table 15 show that the light-emitting element 9 and the comparative light-emitting element 7 can be driven at low voltages.

[0730] As described above, the carbazole compound of one embodiment of the present invention is used for the hole injection layer and the hole transport layer, thereby obtaining an element with high emission efficiency. The reasons for the above phenomena may be as follows: The LUMO energy level of the carbazole compound of one embodiment of the present invention is shallow enough to inhibit the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its band gap is wide enough to inhibit the efficiency reduction caused by exciton energy transfer.

[0731] It is also shown that when the carbazole compound of one embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be obtained.

[0732] [Example 16]

[0733] In this example, the manufacturing method of the light-emitting element constituting one embodiment of the present invention, the test results of the element characteristics, and the test results of the comparative light-emitting element will be described.

[0734] The manufacturing methods of the light-emitting element 10 and the comparative light-emitting element 8 will be described below. The element structure of the light-emitting element obtained in this example is as Figure 62 shown. It should be noted that the organic compounds used in this example are similar to those in the above examples; therefore, the description of the organic compounds is omitted.

[0735] (Light-emitting element 10)

[0736] The light-emitting element 10 is manufactured in a similar manner to the light-emitting element 9 in Example 15, except for the light-emitting layer 1113.

[0737] In the light-emitting element 10, the first light-emitting layer 1113a and the second light-emitting layer 1113b are sequentially stacked on the first electrode 1101 to form the light-emitting layer 1113.

[0738] The first light-emitting layer 1113a is formed by co-evaporation of mPCzPTp synthesized in Example 5 and tris(2-phenylpyridine-N,C 2′ )iridium(III) (abbreviation: Ir(ppy)3). At this time, the weight ratio of mPCzPTp to Ir(ppy)3 is adjusted to 1:0.06 (= mPCzPTp:Ir(ppy)3). The thickness of the first light-emitting layer 1113a is 20 nm.

[0739] Next, 4-[3-(benzo[9,10]phenanthren-2-yl)phenyl]dibenzothiophene (abbreviation: mDBTPTp-II) and Ir(ppy)3 were co-evaporated on the first light-emitting layer 1113a to form the second light-emitting layer 1113b. The weight ratio of mDBTPTp-II to Ir(ppy)3 was adjusted to 1:0.06 (= mDBTPTp-II:Ir(ppy)3). The thickness of the second light-emitting layer 1113b was 20 nm.

[0740] (Comparative light-emitting element 8)

[0741] The comparative light-emitting element 8 was fabricated in a manner similar to the comparative light-emitting element 7 in Example 15, except for the light-emitting layer 1113.

[0742] In the comparative light-emitting element 8, the structure of the light-emitting layer 1113 was similar to that of the above-described light-emitting element 10.

[0743] Table 16 shows the element structures of the light-emitting element 10 and the comparative light-emitting element 8 obtained as described above.

[0744] [Table 16]

[0745]

[0746] *All mixing ratios are expressed as weight ratios.

[0747] The light-emitting element 10 and the comparative light-emitting element 8 were sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was performed at room temperature (the atmosphere was maintained at 25 °C).

[0748] It should be noted that the light-emitting element 10 and the comparative light-emitting element 8 were formed on the same substrate. In addition, in the above two light-emitting elements, except for the hole injection layer and the hole transport layer, each component was formed simultaneously, and the operating characteristics of the two light-emitting elements were measured simultaneously.

[0749] Table 17 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 10 and the comparative light-emitting element 8 at a luminance of approximately 1000 cd / m 2 .

[0750] [Table 17]

[0751] Light-emitting element 10 Comparative light-emitting element 8 Voltage (V) 6.8 6.8 <![CDATA[Current density (mA / cm 2 )]]> 2.4 3.9 Color coordinates (x, y) (0.34,0.61) (0.33,0.61) <![CDATA[Brightness (cd / m 2 )]]> 1100 1100 Current efficiency (cd / A) 47 28 Power efficiency (lm / W) 22 13 External quantum efficiency (%) 14 8.3

[0752] Figure 63 The emission spectra of the light-emitting element 10 and the comparative light-emitting element 8 are shown. AtFigure 63 In this figure, the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (in arbitrary units). Figure 64 and Figure 65 respectively show the voltage-luminance characteristics and luminance-power efficiency characteristics of the light-emitting element 10 and the comparative light-emitting element 8. In Figure 64 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 65 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ).

[0753] As Figure 63 shown, both the emission spectra of the light-emitting element 10 and the comparative light-emitting element 8 have peaks at around 515 nm. The CIE color coordinates in Table 17 also show that the light-emitting element 10 and the comparative light-emitting element 8 exhibit green phosphorescent emission derived from Ir(ppy)3, and all the elements have good carrier balance. In addition, in the light-emitting element 10 and the comparative light-emitting element 8, a carbazole compound according to an embodiment of the present invention is used as the host material of the phosphorescent compound emitting green light, and it is confirmed that the T1 energy level of the carbazole compound according to an embodiment of the present invention is high enough (higher than the T1 energy level of at least one phosphorescent compound emitting green light).

[0754] In addition, Figure 64 , Figure 65 and Table 17 show that the efficiency of the light-emitting element 10 is higher than that of the comparative light-emitting element 8. The reasons for the above phenomena may be as follows: the bandgap of mPCzPTp used for the hole injection layer and the hole transport layer of the light-emitting element 10 in this embodiment is wider than the bandgap of PCzPA used for the comparative light-emitting element 8; the energy transfer in the light-emitting layer is not likely to occur; the LUMO energy level of mPCzPTp is shallow enough to prevent electrons from passing through the light-emitting layer.

[0755] In addition, Figure 64 , Figure 65 and Table 17 show that the light-emitting element 10 and the comparative light-emitting element 8 can be driven at a low voltage.

[0756] As described above, a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, thereby obtaining an element with high emission efficiency. The reasons for the above phenomena may be as follows: the LUMO energy level of the carbazole compound according to an embodiment of the present invention is shallow enough to suppress the leakage of electrons from the light-emitting layer; its HOMO energy level is deep enough to have excellent performance in injecting holes into the light-emitting layer; its bandgap is wide enough to suppress the efficiency reduction caused by exciton energy transfer.

[0757] It is also shown that when a carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be obtained.

[0758] The carbazole compound of an embodiment of the present invention has a wide bandgap and can thus also be preferably used as a host material for a phosphorescent material.

[0759] [Example 17]

[0760] In this example, the manufacturing method of a light-emitting element constituting an embodiment of the present invention and the test results of the element characteristics thereof will be described.

[0761] The manufacturing method of the light-emitting element 11 of this example will be described below. Figure 29 The element structure of the light-emitting element manufactured in this example is shown. The structural formulas of the organic compounds used in this example are as shown below. It should be noted that the description of the structural formulas already shown in the above examples is omitted.

[60]

[0763]

[0764] (Light-emitting element 11)

[0765] In the light-emitting element 11, the first electrode 1101, the electron injection layer 1115, and the second electrode 1103 are formed in a manner similar to that of the light-emitting element 1 in Example 9.

[0766] In the light-emitting element 11, 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) and molybdenum(VI) oxide are co-evaporated on the first electrode 1101 to form a hole injection layer 1111. The thickness of the hole injection layer 1111 is 50 nm. The weight ratio of BPAFLP to molybdenum(VI) oxide is adjusted to 4:2 (=BPAFLP: molybdenum(VI) oxide). It should be noted that the co-evaporation method is a vapor deposition method in which vapor deposition is performed simultaneously from a plurality of evaporation sources in one processing chamber.

[0767] Then, BPAFLP with a thickness of 10 nm is deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0768] The first light-emitting layer 1113 is formed by co-evaporating mPCzPTp synthesized in Example 5 and tris(2-phenylpyridine-N,C 2′ )iridium(III) (abbreviation: Ir(ppy)3). The weight ratio of mPCzPTp to Ir(ppy)3 is adjusted to 1:0.08 (=mPCzPTp: Ir(ppy)3). The thickness of the light-emitting layer 113 is 40 nm.

[0769] Next, a first electron transport layer 1114a is formed on the light-emitting layer 1113 by evaporating mPCzPTp. The thickness of the first electron transport layer 1114a is 10 nm.

[0770] Then, bathophenanthroline (abbreviation: BPhen) with a thickness of 20 nm was deposited on the first electron transport layer 1114a to form the second electron transport layer 1114b.

[0771] Table 18 shows the element structure of the light-emitting element 11 formed as described above.

[0772] [Table 18]

[0773]

[0774] *All mixing ratios are expressed as weight ratios.

[0775] The light-emitting element 11 was sealed in a glove box containing a nitrogen atmosphere to avoid contact with air. Then, the operating characteristics of the light-emitting element were measured. Note that the measurement was performed at room temperature (the atmosphere was maintained at 25 °C).

[0776] Table 19 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting element 11 at a luminance of approximately 1000 cd / m 2 .

[0777] [Table 19]

[0778] Light-emitting element 11 Voltage (V) 5.2 <![CDATA[Current density (mA / cm 2 )]]> 1.7 Color coordinates (x, y) (0.33,0.61) <![CDATA[Brightness (cd / m 2 )]]> 870 Current efficiency (cd / A) 52 Power efficiency (lm / W) 32 External quantum efficiency (%) 15

[0779] Figure 66 shows the emission spectrum of the light-emitting element 11. In Figure 66 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 67 and Figure 68 show the voltage-luminance characteristic and luminance-power efficiency characteristic of the light-emitting element 11, respectively. In Figure 67 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 68 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ).

[0780] According to Figure 66, the emission spectrum of the light-emitting element 11 has a peak at around 515 nm. The CIE color coordinates in Table 19 also show that the light-emitting element 11 exhibits green phosphorescent emission derived from Ir(ppy)3, and all the elements have good carrier balance. In addition, in the light-emitting element 11, a carbazole compound according to an embodiment of the present invention is used as the host material of the phosphorescent compound emitting green light, and it is confirmed that the T1 energy level of the carbazole compound according to an embodiment of the present invention is high enough (higher than the T1 energy level of at least one phosphorescent compound emitting green light).

[0781] In addition, in the light-emitting element 11 of this embodiment, a carbazole compound according to an embodiment of the present invention is used as the electron transport material, and it is confirmed that the carbazole compound according to an embodiment of the present invention is a material with excellent electron transport properties.

[0782] In addition, Figure 67 、 Figure 68 and Table 19 show that the light-emitting element 11 has high efficiency.

[0783] As described above, by using a carbazole compound according to an embodiment of the present invention as the material of the light-emitting element, the light-emitting element can have high efficiency. The carbazole compound according to an embodiment of the present invention has a wide bandgap, and thus can also be preferably used as the host material of the phosphorescent material.

[0784] [Example 18]

[0785] In this embodiment, the manufacturing method of the light-emitting element constituting an embodiment of the present invention and the test results of its element characteristics will be described.

[0786] The manufacturing methods of the light-emitting element 12 and the light-emitting element 13 will be described below. It should be noted that the element structure of the light-emitting element obtained in this embodiment is similar to that Figure 29 shown. The structural formulas of the organic compounds used in this embodiment are shown below. It should be noted that the description of the organic compounds whose structural formulas have been shown is omitted.

[61]

[0788]

[0789] (Light-emitting element 12)

[0790] In the light-emitting element 12, the first electrode 1101, the electron injection layer 1115, and the second electrode 1103 are formed in a manner similar to that of the light-emitting element 1 in Example 9.

[0791] In the light-emitting element 12, 3-(4-(1-naphthyl)phenyl)-9-phenyl-9H-carbazole (abbreviation: PCPN) synthesized in Example 1 and molybdenum(VI) oxide were co-evaporated on the first electrode 1101 to form a hole injection layer 1111. The thickness of the hole injection layer 1111 was 40 nm. The weight ratio of PCPN to molybdenum(VI) oxide was adjusted to 4:2 (=PCPN:molybdenum(VI) oxide). It should be noted that the co-evaporation method is a vapor deposition method in which vapor deposition is carried out simultaneously from a plurality of evaporation sources in one processing chamber.

[0792] Then, PCPN with a thickness of 20 nm was deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0793] The light-emitting layer 1113 was formed by co-evaporating 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II) and iridium(III) bis(3,5-dimethyl-2-phenylpyrazinato)acetylacetonate (abbreviation: Ir(mppr-Me)2dpm). The weight ratio of 2mDBTPDBq-III to Ir(mppr-Me)2dpm was adjusted to 1:0.05 (=2mDBTPDBq-II:Ir(mppr-Me)2dpm). The thickness of the light-emitting layer 113 was 30 nm.

[0794] Next, a first electron transport layer 1114a was formed on the light-emitting layer 1113 by evaporating 2mDBTPDBq-II. The thickness of the first electron transport layer 1114a was 10 nm.

[0795] Then, bathophenanthroline (abbreviation: BPhen) with a thickness of 20 nm was deposited on the first electron transport layer 1114a to form a second electron transport layer 1114b.

[0796] (Light-emitting element 13)

[0797] The light-emitting element 13 was fabricated in a manner similar to the above-described light-emitting element 12 except for the light-emitting layer 1113.

[0798] In the light-emitting element 13, the light-emitting layer 1113 was formed by co-evaporating 2mDBTPDBq-II, PCPN, and Ir(mppr-Me)2dpm. The weight ratio of 2mDBTPDBq-II to PCPN and Ir(mppr-Me)2dpm was adjusted to 0.7:0.3:0.05 (=2mDBTPDBq-II:PCPN:Ir(mppr-Me)2dpm). The thickness of the light-emitting layer 113 was 30 nm.

[0799] Table 20 shows the element structures of the light-emitting elements 12 and 13 obtained as described above.

[0800] [Table 20]

[0801]

[0802] *All mixing ratios are by weight.

[0803] The light-emitting elements 12 and 13 are sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements are measured. Note that the measurement is carried out at room temperature (the atmosphere is maintained at 25 °C).

[0804] It should be noted that the light-emitting elements 12 and 13 are formed on the same substrate. In addition, among the above two light-emitting elements, except for the light-emitting layer 1113, each component is formed simultaneously, and the operating characteristics of the two light-emitting elements are measured simultaneously.

[0805] Table 21 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting elements 12 and 13 at a luminance of approximately 1000 cd / m 2 .

[0806] [Table 21]

[0807]

[0808]

[0809] Figure 69 shows the emission spectra of the light-emitting elements 12 and 13. In Figure 69 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 70 , Figure 71 and Figure 72 show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting elements 12 and 13, respectively. In Figure 70 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 71 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In Figure 72 , the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0810] As Figure 69As shown, both the emission spectra of light-emitting element 12 and light-emitting element 13 have peaks around 580 nm. The CIE color coordinates in Table 21 also show that light-emitting element 12 and light-emitting element 13 exhibit orange phosphorescent emission derived from Ir(mppr-Me)2dpm, and all the elements have good carrier balance. In addition, in light-emitting element 13 of this embodiment, a carbazole compound according to an embodiment of the present invention is used as the host material of the phosphorescent compound emitting orange light, and it is confirmed that the T1 energy level of the carbazole compound according to an embodiment of the present invention is high enough (higher than the T1 energy level of at least one phosphorescent compound emitting orange light). Additionally, it is found that the elements can all be driven at low voltages.

[0811] In addition, Figure 70 、 Figure 71 、 Figure 72 and Table 21 show that light-emitting element 12 and light-emitting element 13 have high efficiency.

[0812] As described above, using a carbazole compound according to an embodiment of the present invention as the material of the light-emitting element, the light-emitting element can have high efficiency. The carbazole compound according to an embodiment of the present invention has a wide bandgap, and thus can also be preferably used as the host material of the phosphorescent material.

[0813] It is also shown that when the carbazole compound according to an embodiment of the present invention is used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage can be fabricated.

[0814] (Reference Example)

[0815] Examples of the synthesis methods of the materials for the light-emitting elements in this embodiment will be described below.

[0816] <Synthesis Example of 2mDBTPDBq-II>

[0817] The synthesis method of 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II) will be described. Its synthesis scheme is shown in (R-1).

[62]

[0819]

[0820] 5.3 g (20 mmol) of 2-chlorodibenz[f,h]quinoxaline, 6.1 g (20 mmol) of 3-(dibenzothiophen-4-yl)phenylboronic acid, 460 mg (0.4 mmol) of tetrakis(triphenylphosphine)palladium(0), 300 mL of toluene, 20 mL of ethanol, and 20 mL of 2 M aqueous potassium carbonate solution were added to a 2 L three-necked flask. The mixture was stirred and degassed under reduced pressure, and the atmosphere in the flask was replaced with nitrogen. The mixture was stirred at 100 °C for 7.5 h under a nitrogen stream. After cooling to room temperature, the obtained mixture was filtered to obtain a white solid. The solid obtained by filtration was washed thoroughly with water and ethanol in sequence, and then dried. The obtained solid was dissolved in 600 mL of hot toluene, and then filtered through C salt and Florisil to obtain a transparent colorless filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. The chromatography was carried out at about 40 °C using toluene as the eluent. Acetone and ethanol were added to the solid obtained at this time, and then ultrasonic irradiation was carried out. Then, the formed suspended solid was filtered, and the obtained solid was dried to obtain 7.85 g of the target substance as a white powder, with a yield of 80%.

[0821] The above-mentioned target substance is relatively easily soluble in hot toluene, but it is prone to precipitation when cooled. In addition, the substance is not easily soluble in other organic solvents such as acetone and ethanol. Therefore, through the above simple method, high-yield synthesis can be achieved by utilizing different solubilities. Specifically, after the reaction is completed, the mixture returns to room temperature, and the precipitated solid is collected by filtration, so that most of the impurities can be easily removed. In addition, through column chromatography using hot toluene as the eluent, the generated substance (which is prone to precipitation) can be easily purified.

[0822] The 4.0 g of the obtained white powder was sublimated and purified by the train sublimation method. In the sublimation purification, the white powder was heated at 300 °C under a pressure of 5.0 Pa and an argon gas flow rate of 5 mL / min. After sublimation purification, 3.5 g of the target substance as a white powder was obtained, with a yield of 88%.

[0823] Nuclear magnetic resonance (NMR) method determined that the compound was 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), which was the target substance.

[0824] The obtained substance's 1 1H NMR data are as follows:

[0825] 11H NMR (CDCl3, 300 MHz): δ (ppm) = 7.45 - 7.52 (m, 2H), 7.59 - 7.65 (m, 2H), 7.71 - 7.91 (m, 7H), 8.20 - 8.25 (m, 2H), 8.41 (d, J = 7.8 Hz, 1H), 8.65 (d, J = 7.5 Hz, 2H), 8.77 - 8.78 (m, 1H), 9.23 (dd, J = 7.2 Hz, 1.5 Hz, 1H), 9.42 (dd, J = 7.8 Hz, 1.5 Hz, 1H), 9.48 (s, 1H).

[0826] <Synthesis method of Ir(mppr-Me)2dpm>

[0827] The synthesis method of bis(neopentanoylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: Ir(mppr-Me)2dpm) will be described below. The synthesis scheme is shown in (R-2).

[63]

[0829]

[0830] First, 20 mL of 2-ethoxyethanol, 1.55 g of the binuclear complex di-μ-chloro-bis[bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III)] (abbreviation: [Ir(mppr-Me)2Cl]2), 0.8 mL of neopentanoylacetone, and 1.38 g of sodium carbonate were mixed. The mixture was irradiated with microwave for 30 minutes under argon bubbling to carry out the reaction. After the reaction, the reaction solution was cooled to room temperature, and water was added thereto. The mixed solution was separated into an organic layer and an aqueous layer, and the aqueous layer was extracted with dichloromethane. The organic layer was combined with the extract, the mixture was washed with water, and then dried over anhydrous magnesium sulfate. Thereafter, the mixture was subjected to gravity filtration, and the filtrate was concentrated to dryness and solidified. The solid was recrystallized from a mixed solvent of dichloromethane and ethanol to obtain a red powder with a yield of 67%. It should be noted that microwave irradiation was carried out using a microwave synthesis system (Discover, manufactured by CEM Corporation).

[0831] It should be noted that the nuclear magnetic resonance (NMR) method confirmed that the mixture was the organometallic complex [Ir(mppr-Me)2dpm], which was the target substance.

[0832] The 1 1H NMR data of the obtained compound are as follows:

[0833] 11H NMR. δ(CDCl3): 0.90 (s, 1H), 2.59 (s, 6H), 3.04 (s, 6H), 5.49 (s, 1H), 6.32 (dd, 2H), 6.70 (dt, 2H), 6.88 (dt, 2H), 7.86 (d, 2H), 8.19 (s, 2H).

[0834] [Example 19]

[0835] In this example, the manufacturing method of a light-emitting element constituting one embodiment of the present invention and the test results of the element characteristics will be described.

[0836] The manufacturing method of the light-emitting elements 14 - 17 will be described below. It should be noted that the element structure of the light-emitting element obtained in this example is the same as Figure 29 shown. The structural formulas of the organic compounds used in this example are shown below. It should be noted that the description of the organic compounds whose structural formulas have been shown is omitted.

[64]

[0838]

[0839] (Light-emitting element 14)

[0840] The light-emitting element 14 is fabricated in a manner similar to the light-emitting element 12 in Example 18, except for the light-emitting layer 1113.

[0841] In the light-emitting element 14, the light-emitting layer 1113 is formed by co-evaporation of 2-[3-(dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 4,4′-bis(1-naphthyl)-4″-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), and iridium(III) bis(3,5-dimethyl-2-phenylpyrazine)(dineopentanoylmethane) (abbreviation: Ir(mppr-Me)2dpm). The weight ratio of 2mDBTPDBq-II to PCBNBB and Ir(mppr-Me)2dpm is adjusted to 0.8:0.2:0.05 (= 2mDBTPDBq-II:PCBNBB:Ir(mppr-Me)2dpm). The thickness of the light-emitting layer 113 is 40 nm.

[0842] (Light-emitting element 15)

[0843] The light-emitting element 15 is fabricated in a manner similar to the above-described light-emitting element 14, except for the hole injection layer 1111 and the hole transport layer 1112.

[0844] In the light-emitting element 15, 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn) synthesized in Example 2 and molybdenum(VI) oxide were co-evaporated to form a hole injection layer 1111 on the first electrode 1101. The thickness of the hole transport layer 1111 was 40 nm. The weight ratio of PCPPn to molybdenum(VI) oxide was adjusted to 4:2 (=PCPPn: molybdenum(VI) oxide).

[0845] Then, PCPPn with a thickness of 20 nm was deposited on the hole injection layer 1111 to form a hole transport layer 1112.

[0846] (Light-emitting element 16)

[0847] The light-emitting element 16 was fabricated in a similar manner to the above-described light-emitting element 14, except for the hole injection layer 1111.

[0848] In the light-emitting element 16, 9-[4-(9-phenylcarbazol-3-yl)phenyl]-10-phenylanthracene (abbreviation: PCzPA) and molybdenum(VI) oxide were co-evaporated to form a hole injection layer 1111 on the first electrode 1101. The thickness of the hole injection layer 1111 was 40 nm. The weight ratio of PCzPA to molybdenum(VI) oxide was adjusted to 4:2 (=PCzPA: molybdenum).

[0849] (Light-emitting element 17)

[0850] The light-emitting element 17 was fabricated in a similar manner to the above-described light-emitting element 15, except for the hole injection layer 1111. The hole injection layer 1111 of the light-emitting element 17 was fabricated in a similar manner to the above-described light-emitting element 16.

[0851] Table 22 shows the element structures of the light-emitting elements 14 - 17 formed as described above.

[0852] [Table 22]

[0853]

[0854]

[0855] *All mixing ratios represent weight ratios.

[0856] The light-emitting elements 14 - 17 were sealed in a glove box containing a nitrogen atmosphere to avoid contact with air. Then, the operating characteristics of these elements were measured. Note that the measurement was performed at room temperature (the atmosphere was maintained at 25 °C).

[0857] Note that the light-emitting elements 14-17 are formed on the same substrate. In addition, among the above four light-emitting elements, components other than the hole injection layer 1111 and the hole transport layer 1112 are formed simultaneously, and the operating characteristics of the four light-emitting elements are measured simultaneously.

[0858] Table 23 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting elements 14-17 at a luminance of about 1000 cd / m 2 ).

[0859] [Table 23]

[0860] Light-emitting element 14 Light-emitting element 15 Light-emitting element 16 Light-emitting element 17 Voltage (V) 2.8 2.9 2.8 2.9 <![CDATA[Current density (mA / cm 2 )]]> 1.5 1.8 1.5 1.9 Color coordinates (x, y) (0.52,0.47) (0.52,0.47) (0.52,0.47) (0.52,0.47) <![CDATA[Brightness (cd / m 2 )]]> 1050 1200 980 1200 Current efficiency (cd / A) 68 68 65 66 Power efficiency (lm / W) 77 74 73 71 External quantum efficiency (%) 24 24 23 23

[0861] Figure 73 shows the emission spectra of the light-emitting elements 14-17. In Figure 73 , the horizontal axis represents the wavelength (nm), and the vertical axis represents the emission intensity (arbitrary unit). Figure 74 , Figure 75 and Figure 76 show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting elements 14-17, respectively. In Figure 74 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 75 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In Figure 76 , the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0862] As Figure 73 shows, the light-emitting elements 14-17 have a peak at around 580 nm. The CIE color coordinates in Table 23 also show that the light-emitting elements 14-17 exhibit orange phosphorescent emission derived from Ir(mppr-Me)2dpm, and all the elements have good carrier balance.

[0863] In addition, Figure 74 , Figure 75 , Figure 76 and Table 23 show that the light-emitting elements 14-17 have high efficiency.

[0864] In addition, it was also found that the light-emitting elements 14 and 15, which respectively used the layer containing the carbazole compound of an embodiment of the present invention for the hole injection layer 1111, had higher efficiency than the light-emitting elements 16 and 17. Additionally, it was found that the light-emitting elements 14 and 15 could be driven at the same low voltage as the comparative light-emitting elements 16 and 17.

[0865] In addition, reliability tests were performed on the fabricated light-emitting elements 14 - 17. In the reliability test, the initial brightness was set to 5000 cd / m2, and these elements were operated under the condition of a constant current density, and the brightness was measured at regular intervals. The results of the reliability test are shown in Figure 77 In Figure 77 the horizontal axis represents the current time (hours), and the vertical axis represents the ratio of the brightness at each time point to the initial brightness, that is, the normalized brightness (%).

[0866] According to Figure 77 , the light-emitting elements 14 - 17 were all not prone to brightness reduction over time, and each element had a long lifespan. Even after being driven for 190 hours, the light-emitting elements 14, 15, 16, and 17 still maintained 87%, 83%, 81%, and 79% of their initial brightness, respectively.

[0867] As described above, using the carbazole compound of an embodiment of the present invention as the material of the light-emitting element enables the light-emitting element to have high efficiency.

[0868] In addition, it was shown that when the carbazole compound of an embodiment of the present invention was used for the hole injection layer and the hole transport layer, a light-emitting element with a low driving voltage could be fabricated.

[0869] In addition, it was also shown that when the carbazole compound of an embodiment of the present invention was used for the hole injection layer and the hole transport layer, a light-emitting element with a long lifespan could be fabricated.

[0870] [Example 20]

[0871] In this example, various manufacturing methods of the light-emitting elements that respectively constitute an embodiment of the present invention and the test results of the element characteristics, as well as the test results of the comparative light-emitting elements, will be described.

[0872] The manufacturing methods of the light-emitting element 18, the light-emitting element 19, and the comparative light-emitting element 9 in this example will be described below. It should be noted that the element structure of the light-emitting element fabricated in this example is similar to that shown in Figure 62 . In addition, the structural formulas of the organic compounds used in this example have been shown; therefore, the description thereof is omitted.

[0873] (Light-emitting element 18)

[0874] The light-emitting element 18 is fabricated in a manner similar to the light-emitting element 8 in the above-described Embodiment 14, except for the hole injection layer 1111, the hole transport layer 1112, and the light-emitting layer 1113.

[0875] In the light-emitting element 18, the PCPN synthesized in Embodiment 1 and molybdenum(VI) oxide are co-evaporated to form the hole injection layer 1111 on the first electrode 1101. The thickness of the hole injection layer 1111 is 50 nm. The weight ratio of PCPN to molybdenum(VI) oxide is adjusted to 4:2 (= PCPN: molybdenum(VI) oxide).

[0876] Then, 10 nm of PCPN is deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0877] In the light-emitting element 18, the first light-emitting layer 1113a and the second light-emitting layer 1113b are sequentially stacked on the first electrode 1101 to form the light-emitting layer 1113.

[0878] The first light-emitting layer 1113a is formed by co-evaporating PCPN and 1,6FLPAPrn. The weight ratio of PCPN to 1,6FLPAPrn is adjusted to 1:0.05 (= PCPN: 1,6FLPAPrn). The thickness of the first light-emitting layer 1113a is 10 nm.

[0879] The second light-emitting layer 1113b is formed by co-evaporating CzPA and 1,6FLPAPrn. The weight ratio of CzPA to 1,6FLPAPrn is adjusted to 1:0.05 (= CzPA: 1,6FLPAPrn). The thickness of the second light-emitting layer 1113b is 25 nm.

[0880] (Light-emitting element 19)

[0881] The light-emitting element 19 is fabricated in a manner similar to the above-described light-emitting element 18, except for the hole injection layer 1111, the hole transport layer 1112, and the first light-emitting layer 1113a.

[0882] In the light-emitting element 19, the PCPPn synthesized in Embodiment 2 and molybdenum(VI) oxide are co-evaporated to form the hole injection layer 1111 on the first electrode 1101. The thickness of the hole injection layer 111 is 50 nm. The weight ratio of PCPPn to molybdenum(VI) oxide is adjusted to 4:2 (= PCPPn: molybdenum(VI) oxide).

[0883] Then, 10 nm of PCPPn is deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0884] In the light-emitting element 19, the first light-emitting layer 1113a is formed by co-evaporation of PCPPn and 1,6FLPAPrn. The weight ratio of PCPPn to 1,6FLPAPrn is adjusted to 1:0.05 (=PCPPn:1,6FLPAPrn). The thickness of the first light-emitting layer 1113a is 10 nm.

[0885] (Comparative light-emitting element 9)

[0886] The comparative light-emitting element 9 is fabricated in a manner similar to that of the light-emitting element 18, except for the hole injection layer 1111, the hole transport layer 1112, and the first light-emitting layer 1113a.

[0887] In the comparative light-emitting element 9, PCzPA and molybdenum(VI) oxide are co-evaporated on the first electrode 1101 to form the hole injection layer 1111. The thickness of the hole injection layer 1111 is 50 nm. The weight ratio of PCzPA to molybdenum(VI) oxide is adjusted to 4:2 (=PCzPA:molybdenum(VI) oxide).

[0888] Then, PCzPA with a thickness of 10 nm is deposited on the hole injection layer 1111 to form the hole transport layer 1112.

[0889] In the comparative light-emitting element 9, the first light-emitting layer 1113a is formed by co-evaporation of PCzPA and 1,6FLPAPrn. The weight ratio of PCzPA to 1,6FLPAPrn is adjusted to 1:0.05 (=PCzPA:1,6FLPAPrn). The thickness of the first light-emitting layer 1113a is 10 nm.

[0890] Table 24 shows the device structures of the light-emitting elements 18 and 19 and the comparative light-emitting element 9 obtained as described above.

[0891] [Table 24]

[0892]

[0893] *All mixing ratios represent weight ratios.

[0894] The light-emitting elements 18 and 19 and the comparative light-emitting element 9 are sealed in a glove box with a nitrogen-containing atmosphere to avoid contact with air. Then, the operating characteristics of these elements are measured. Note that the measurement is carried out at room temperature (the atmosphere is maintained at 25 °C).

[0895] It should be noted that the light-emitting elements 18, 19, and the comparative light-emitting element 9 are formed on the same substrate. In addition, among the above three light-emitting elements, the components other than the hole injection layer 1111, the hole transport layer 1112, and the first light-emitting layer 1113a are formed simultaneously, and the operating characteristics of the three light-emitting elements are measured simultaneously.

[0896] Table 25 shows the voltage (V), current density (mA / cm 2 ), CIE color coordinates (x, y), luminance (cd / m 2 ), current efficiency (cd / A), power efficiency (lm / W), and external quantum efficiency (%) of the light-emitting elements 18 and 19 and the comparative light-emitting element 9 at a luminance of about 1000 cd / m 2 ).

[0897] [Table 25]

[0898]

[0899]

[0900] Figure 78 shows the emission spectra of the light-emitting elements 18 and 19 and the comparative light-emitting element 9. In Figure 78 , the horizontal axis represents the wavelength (nm) and the vertical axis represents the emission intensity (arbitrary unit). Figure 79 , Figure 80 and Figure 81 show the voltage-luminance characteristics, luminance-current efficiency characteristics, and luminance-power efficiency characteristics of the light-emitting elements 18 and 19 and the comparative light-emitting element 9, respectively. In Figure 79 , the vertical axis represents the luminance (cd / m 2 ), and the horizontal axis represents the voltage (V). In Figure 80 , the vertical axis represents the current efficiency (cd / A), and the horizontal axis represents the luminance (cd / m 2 ). In Figure 81 , the vertical axis represents the power efficiency (lm / W), and the horizontal axis represents the luminance (cd / m 2 ).

[0901] As Figure 78 shows, the emission spectra of the light-emitting elements 18 and 19 and the comparative light-emitting element 9 all have peaks at around 470 nm. The CIE color coordinates in Table 25 also show that the light-emitting elements 18 and 19 and the comparative light-emitting element 9 exhibit blue light emission derived from 1,6FLPAPrn, and all the elements have good carrier balance. In addition, in the light-emitting elements 18 and 19, a carbazole compound according to an embodiment of the present invention is used as the host material of the fluorescent compound that emits blue fluorescence, and it is confirmed that the S1 energy level of the carbazole compound according to an embodiment of the present invention is high enough (higher than the S1 energy level of at least one fluorescent compound that emits blue light).

[0902] Specifically, the carbazole compounds according to an embodiment of the present invention are used for the first light-emitting layer 1113a in the light-emitting elements 18 and 19, respectively, and the efficiency is higher than that of the comparative light-emitting element 9. This indicates that the S1 energy level of the carbazole compound according to an embodiment of the present invention is high enough.

[0903] In addition, Figure 79 , Figure 80 , Figure 81 and Table 25 show that the light-emitting elements 18 and 19 can be driven at the same low voltage as the comparative light-emitting element 9, and the light-emitting elements 18 and 19 have higher efficiency than the comparative light-emitting element 9. The reasons for the above phenomena may be as follows. In the present embodiment, the band gap of the carbazole compound of one embodiment of the present invention used in the light-emitting elements 18 and 19 is wider than that of PCzPA used in the comparative light-emitting element 9; therefore, when the carbazole compound is used as the material of the hole transport layer in contact with the light-emitting layer, the transfer of energy from the light-emitting layer can be effectively suppressed. The LUMO level (absolute value) of the carbazole compound of one embodiment of the present invention used in the light-emitting elements 18 and 19 in the present embodiment is shallower (smaller) than the LUMO level of PCzPA used in the comparative light-emitting element 9; therefore, the carrier loss caused by the leakage of electrons from the light-emitting layer can be suppressed. In addition, in the present embodiment, the HOMO level (absolute value) of the carbazole compound of one embodiment of the present invention used in the light-emitting elements 18 and 19 is deeper (larger) than the HOMO level of PCzPA used in the comparative light-emitting element 9; therefore, holes can be effectively injected into the light-emitting layer.

[0904] In addition, it is found that all the light-emitting elements can be driven at the same low voltage as the comparative light-emitting element, and all the light-emitting elements have good carrier transport properties. This indicates that the carrier transport properties of the carbazole compound of one embodiment of the present invention are excellent.

[0905] As described above, when the carbazole compound of one embodiment of the present invention is used as the material of the light-emitting element, the light-emitting element can have high efficiency. In addition, the carbazole compound of one embodiment of the present invention can be used as the host material of the blue fluorescent material.

[0906] [Example 21]

[0907] In the present embodiment, an example of preparing the carbazole compound 9-phenyl-9H-3-{4-[3,5-bis(phenanthren-9-yl)phenyl]phenyl}carbazole (abbreviation: Pn2BPPC) of one embodiment of the present invention will be described. In the general formula (G1), R 1 is phenyl, R 2 is hydrogen, α 3 is a biphenyldiyl having a phenanthryl group as a substituent, and Ar 3 is a phenanthryl group.

[65]

[0909]

[0910] [Step 1: Synthesis method of 9-[3-chloro-5-(phenanthren-9-yl)phenyl]phenanthrene (abbreviation: Cl-PPn2)]

[0911] In a 200 mL three-necked flask, a mixture of 2.90 g (10.7 mmol) of 1,3-dibromo-5-chlorobenzene, 5.0 g (22.5 mmol) of 9-phenanthreneboronic acid, 50.6 mg (0.23 mmol) of palladium(II) acetate, 207 mg (0.68 mmol) of tris(o-tolyl)phosphine, 70 mL of toluene, 7 mL of ethanol, and 20 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 85 °C for 6 hours in a nitrogen atmosphere to carry out the reaction. Additionally, 50.6 mg (0.23 mmol) of palladium(II) acetate and 207 mg (0.68 mmol) of tris(o-tolyl)phosphine were added to the mixture, and the mixture was heated and stirred at 85 °C for 7.5 hours in a nitrogen atmosphere, and then heated and stirred at 110 °C for 7.5 hours to carry out the reaction.

[0912] After the reaction, 300 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through Florisil (produced by Wacker Chemie AG, catalog number 540-00135), alumina (neutral, produced by Merck & Co., Inc.), and C salt (produced by Wacker Chemie AG, catalog number 531-16855). The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:5) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and toluene and hexane were added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 3.11 g of the target substance as a white powder, with a yield of 63%. The reaction scheme of this synthesis method is shown in (F8-1).

[66]

[0914]

[0915] The Rf value of the target substance was 0.25, measured by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane in a ratio of 1:10).

[0916] The compound obtained in Step 1 was measured by nuclear magnetic resonance (NMR) method. The measurement data are shown below.

[0917] 11H NMR (CDCl3, 300 MHz): δ (ppm) = 7.59 - 7.73 (m, 11H), 7.79 (s, 2H), 7.92 (d, J = 7.81 Hz, 2H), 8.06 (d, J = 8.30 Hz, 2H), 8.73 (d, J = 8.30 Hz, 2H), 8.79 (d, J = 8.30 Hz, 2H).

[0918] Figure 82A and 82B is 1 1H NMR spectrum. It should be noted that Figure 82B is Figure 82A an enlarged view in the range of 7.00 ppm to 9.00 ppm. The test results confirm that the target substance 9-[3-chloro-5-(phenanthren-9-yl)phenyl]phenanthrene (abbreviation: Cl-PPn2) can be obtained.

[0919] [Step 2: Synthesis method of 9-phenyl-9H-3-{4-[3,5-bis(phenanthren-9-yl)phenyl]phenyl}carbazole (abbreviation: Pn2BPPC)]

[0920] In a 200 mL three-necked flask, a mixture of 1.04 g (2.87 mmol) of 9-[3-chloro-5-(phenanthren-9-yl)phenyl]phenanthrene, 2.00 g (4.31 mmol) of 3-(9-phenyl-9H-carbazol-3-yl)phenyl-4-boronic acid, 49.5 mg (0.09 mmol) of bis(dibenzylideneacetone)palladium(0), 91.8 mg (0.24 mmol) of 2'-(dicyclohexylphosphino)acetophenone ethylene ketal, 1.31 g (8.61 mmol) of cesium fluoride(I) and 30 ml of xylene was heated and stirred at 150 °C for 12 hours under a nitrogen atmosphere to carry out the reaction.

[0921] After the reaction, 500 mL of toluene was added to the reaction mixture solution, and the mixture solution was filtered through alumina (neutral, produced by Merck) and C salt (produced by Wacker Chemie AG, catalog number 531-16855). The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:5) was used as the elution solvent for chromatography. The concentrated fraction was obtained, and hexane was added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 1.9 g of the target substance as a white powder, with a yield of 89%. The reaction scheme of this synthesis method is shown in (F8-2).

[67]

[0923]

[0924] The Rf value of the target substance was 0.29, measured by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane with a ratio of 1:10).

[0925] The compound obtained in Step 2 above was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0926] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.43 (d, J = 3.4 Hz, 2H), 7.46 - 7.50 (m, 2H), 7.60 - 7.99 (m, 25H), 8.19 - 8.23 (m, 3H), 8.41 (d, J = 0.98 Hz, 1H), 8.76 (d, J = 8.30 Hz, 2H), 8.82 (d, J = 7.32 Hz, 2H).

[0927] Figure 83A and 83B is 1 the H NMR spectrum. It should be noted that Figure 83B is Figure 83A an enlarged view in the range of 7.00 ppm to 9.00 ppm. The test results confirmed that the target substance 9-phenyl-9H-3-{4-[3,5-bis(phenanthren-9-yl)phenyl]phenyl}carbazole (abbreviation: Pn2BPPC) could be obtained.

[0928] It should be noted that although in this example, the phenanthrene compound contains chlorine as the reaction group for coupling with the carbazole compound described in this example, it is not limited thereto, and a phenanthrene compound containing iodine or bromine as the reaction group can also be used. For example, the phenanthrene compound that can be used in Step 2 can be represented by the general formula (I1). It should be noted that when the phenanthrene compound represented by the general formula (I1) contains bromine or iodine as the reaction group, Pn2BPPC (abbreviation) can be synthesized in a similar manner to Step 2 above. In Step 1, when phenanthrene-9-boronic acid and trihalobenzene react specifically in a ratio of 2:1, it is preferred that the reaction activity of the halogen reacting with boric acid is higher than the halogen represented by X. Therefore, when X bonded to benzene is chlorine, the halogens at the 3-position and 5-position are preferably bromine or iodine. When X bonded to benzene is bromine, the halogens at the 3-position and 5-position are preferably iodine.

[68]

[0930]

[0931] It should be noted that in the general formula (I1), X represents chlorine, bromine or iodine.

[0932] Figure 84A shows the absorption spectrum of Pn2BPPC in a toluene solution of Pn2BPPC, Figure 84B showing its emission spectrum.Figure 85A The absorption spectrum of the Pn2BPPC thin film is shown, Figure 85B and its emission spectrum is shown. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics). Measurements were performed on samples prepared as follows: The solution was placed in a quartz cell, and a thin film was obtained on a quartz substrate by evaporation. Figure 84A The absorption spectrum of Pn2BPPC in a Pn2BPPC solution is shown, obtained by subtracting the absorption spectra of the quartz cell and toluene placed therein. Figure 85A The absorption spectrum of the thin film is shown, obtained by subtracting the absorption spectrum of the quartz substrate. At Figure 84A and 84B as well as Figure 85A and 85B the horizontal axis represents the wavelength (nm), and the vertical axis represents the intensity (arbitrary unit). For the case of the toluene solution, an absorption peak was observed at approximately 303 nm, and the maximum emission wavelength was 388 nm (excitation wavelength: 340 nm). For the case of the thin film, an absorption peak was observed at approximately 306 nm, and the maximum emission wavelength was 417 nm (excitation wavelength: 306 nm).

[0933] The absorption spectrum shows that the Pn2BPPC described in this example is a material with weak absorption of light in the visible range. In addition, the emission spectrum shows that Pn2BPPC exhibits blue-violet light emission.

[0934] In this example, Pn2BPPC (abbreviation) in the general formula (G1) is preferred for the following reasons: α 3 The biphenyl group of

[0935] [Example 22]

[0936] In this example, an example of 9-phenyl-9H-3-[3,5-bis(phenanthren-9-yl)phenyl]carbazole (abbreviation: Pn2PPC) represented by the structural formula (197) in Embodiment 1 will be described.

[69]

[0938]

[0939] [Step 1: Synthesis method of 3-(3,5-dichlorophenyl)-9-phenyl-9H-carbazole (abbreviation: PCPCl2)]

[0940] In a 200 mL three-necked flask, a mixture of 5.0 g (22.1 mmol) of 3-(9-phenyl-9H-carbazole)boronic acid, 7.63 g (26.6 mmol) of 1-bromo-3,5-dichlorobenzene, 58.4 mg (0.26 mmol) of palladium(II) acetate, 237 mg (0.78 mmol) of tris(o-tolyl)phosphine, 98 mL of toluene, 10 mL of ethanol, and 32 mL of an aqueous potassium carbonate solution (2 mol / L) was stirred and degassed under reduced pressure, and then heated and stirred at 80 °C for 7 hours under a nitrogen atmosphere to carry out the reaction.

[0941] After the reaction, 500 mL of toluene was added to the reaction solution, and the organic layer of the mixture solution was filtered through Florisil, alumina, and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:10) was used as the elution solvent for chromatography. The obtained fraction was concentrated, and toluene and hexane were added thereto. The mixture was irradiated with ultrasonic waves and then recrystallized to obtain 9.09 g of a white powdery target substance with a yield of 100%. The reaction scheme of this synthesis method is shown in (F9-1).

[70]

[0943]

[0944] The Rf value of the target substance was 0.43, measured by silica gel thin-layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane in a ratio of 1:10).

[0945] The compound obtained in Step 1 was measured by nuclear magnetic resonance (NMR). The measurement data are shown below.

[0946] 1 H NMR (CDCl3, 300 MHz): δ (ppm) = 7.26 - 7.34 (m, 2H), 7.40 - 7.53 (m, 4H), 7.57 - 7.67 (m, 7H), 8.20 (d, J = 7.81 Hz, 1H), 8.31 (d, J = 0.98 Hz, 1H).

[0947] Figure 86A and 86B is 1 the H NMR spectrum. It should be noted that Figure 86B is Figure 86A an enlarged view in the range of 7.00 ppm to 8.50 ppm. The test results confirmed that the target substance 3-(3,5-dichlorophenyl)-9-phenyl-9H-carbazole (abbreviation: PCPCl2) could be obtained.

[0948] [Step 2: Synthesis method of 9-phenyl-9H-3-[3,5-bis(phenanthren-9-yl)phenyl]carbazole (abbreviation: Pn2PPC)]

[0949] In a 200 mL three-necked flask, a mixture of 4.29 g (19.3 mmol) of 9-phenanthreneboronic acid, 3.0 g (7.73 mmol) of 3-(3,5-dichlorophenyl)-9-phenyl-9H-carbazole, 86.3 mg (0.15 mmol) of bis(dibenzylideneacetone)palladium(0), 166 mg (0.46 mmol) of 2'-(dicyclohexylphosphino)acetophenone ethylene ketal, 6.98 g (46 mmol) of cesium fluoride(I), and 30 mL of xylene was heated and stirred at 120 °C for 10 hours under a nitrogen atmosphere to carry out the reaction. Then, 858 mg (3.87 mmol) of 9-phenanthreneboronic acid, 86.3 mg (0.15 mmol) of bis(dibenzylideneacetone)palladium(0), and 166 mg (0.46 mmol) of 2'-(dicyclohexylphosphino)acetophenone ethylene ketal were added to the mixture, and the mixture was heated and stirred at 120 °C for 8 hours under a nitrogen atmosphere to carry out the reaction.

[0950] After the reaction, 500 mL of toluene was added to the reaction mixture solution, and the organic layer of the mixture solution was filtered through alumina and C salt. The obtained filtrate was washed with water, and magnesium sulfate was added thereto to absorb moisture. The suspension was filtered to obtain a filtrate. The obtained filtrate was concentrated and purified by silica gel column chromatography. At this time, a mixed solvent of toluene and hexane (toluene:hexane = 1:5) was used as the elution solvent for chromatography. The obtained fraction was concentrated to obtain 0.93 g of the target substance as a white powder, and the yield was 18%. The reaction scheme of this synthesis method is shown in (F9-2).

[71]

[0952]

[0953] The Rf value of the target substance was 0.18, measured by silica gel thin layer chromatography (TLC) (the elution solvent was ethyl acetate and hexane in a ratio of 1:10).

[0954] The compound obtained in Step 2 was measured by nuclear magnetic resonance (NMR) method. The measurement data are shown below.

[0955] 11H NMR (CDCl3, 300 MHz): δ (ppm) = 7.41 - 7.643 (d, J = 3.4 Hz, 2H), 7.48 - 7.51 (d, J = 8.30 Hz, 2H), 7.60 - 8.05 (m, 20H), 8.15 - 8.18 (d, J = 9.3 Hz, 2H), 8.41 (d, J = 0.98 Hz, 1H), 8.79 (dd, J = 8.3 Hz, 18.6 Hz, 4H).

[0956] Figure 87A and 87B is 1 1H NMR spectrum. It should be noted that Figure 87B is Figure 87A an enlarged view in the range of 7.00 ppm to 9.00 ppm. The test results confirm that the target substance 9-phenyl-9H-3-[3,5-bis(phenanthren-9-yl)phenyl]carbazole (abbreviation: Pn2PPC) can be obtained.

[0957] It should be noted that although in this example, the carbazole compound contains chlorine as the reaction group for coupling with the phenanthrene compound described in this example, it is not limited thereto, and a carbazole compound containing iodine or bromine as the reaction group can also be used. For example, the carbazole compound that can be used in step 2 can be represented by general formula (I2). It should be noted that when the carbazole compound represented by general formula (I2) contains bromine or iodine as the reaction group, Pn2BPPC can be synthesized in a manner similar to step 2 above. In step 1, when 9-phenyl-9H-carbazol-3-ylboronic acid reacts with trihalobenzene specifically in a ratio of 1:1, it is preferred that the reaction activity of the halogen reacting with boric acid is higher than the halogen represented by X. Therefore, when X is bonded to benzene at the 1-position and 3-position respectively, the halogen at the 5-position is preferably bromine or iodine. When X bonded to benzene is bromine, the halogen at the 5-position is preferably iodine.

[72]

[0959]

[0960] It should be noted that in general formula (I2), X represents chlorine, bromine or iodine.

[0961] Figure 88A shows the absorption spectrum of Pn2PPC in the toluene solution of Pn2PPC, Figure 88B shows its emission spectrum. Figure 89A shows the absorption spectrum of the Pn2PPC thin film, Figure 89BThe emission spectrum thereof was shown. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics K.K.). Measurements were made on samples prepared as follows: The solution was placed in a quartz cell, and a thin film was obtained on a quartz substrate by evaporation. Figure 88A The absorption spectrum of Pn2PPC in the Pn2PPC solution was shown, obtained by subtracting the absorption spectra of the quartz cell and toluene placed therein. Figure 89A The absorption spectrum of the thin film was shown, obtained by subtracting the absorption spectrum of the quartz substrate. At Figure 88A and 88B as well as Figure 89A and 89B In and, the horizontal axis represents wavelength (nm), and the vertical axis represents intensity (arbitrary unit). For the case of the toluene solution, an absorption peak was observed at approximately 298 nm, and the maximum emission wavelength was 381 nm (excitation wavelength: 311 nm). For the case of the thin film, an absorption peak was observed at approximately 303 nm, and the maximum emission wavelength was 409 nm (excitation wavelength: 304 nm).

[0962] The absorption spectrum shows that the Pn2PPC described in this example is a material having weak absorption of light in the visible range. In addition, the emission spectrum shows that Pn2PPC exhibits emission of blue-violet light.

[0963] This application is based on Japanese Patent Application No. 2010-215856 filed with the Japan Patent Office on September 27, 2010, the entire content of which is incorporated herein by reference.

Claims

1. An organic compound represented by the general formula (G1): wherein R 1 represents a substituted or unsubstituted naphthyl group, wherein R 2 represents any one of hydrogen, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituent represented by the general formula (G1-2); wherein α 3 represents an unsubstituted phenylene or an unsubstituted biphenylylene, where α 2 is the same as α 3 and wherein Ar 3 represents any one of a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group, wherein Ar 2 is the same as Ar 3 and Among them, in the case of R 1 , R 2 and Ar 3 in the case of having substituents, the substituents are respectively any one of an alkyl group having 1 to 12 carbon atoms, an unsubstituted phenyl group, an unsubstituted biphenyl group, an unsubstituted naphthyl group, an unsubstituted phenanthryl group, and an unsubstituted benzo[9,10]phenanthryl group.

2. An organic compound represented by the general formula (G1): wherein R 1 represents 2-naphthyl, wherein R 2 represents any one of hydrogen, an alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted phenyl group, a substituted or unsubstituted biphenyl group, and a substituent represented by the general formula (G1-2); where α 3 represents an unsubstituted phenylene or an unsubstituted biphenylylene, where α 2 is the same as α 3 and wherein Ar 3 represents any one of a substituted or unsubstituted naphthyl group, a substituted or unsubstituted phenanthryl group, and a substituted or unsubstituted benzo[9,10]phenanthryl group, wherein Ar 2 is the same as Ar 3 and Among them, in R 2 and Ar 3 in the case of having substituents, the substituents are respectively any one of an alkyl group having 1 to 12 carbon atoms, an unsubstituted phenyl group, an unsubstituted biphenyl group, an unsubstituted naphthyl group, an unsubstituted phenanthryl group, and an unsubstituted benzo[9,10]phenanthryl group.

3. The organic compound according to claim 1 or 2, wherein R 2 is represented by the general formula (G1-2), and wherein the substituent R 2 and the substituent α 3 -Ar 3 are the same.

4. The organic compound according to claim 1 or 2, wherein R 2 is represented by the general formula (G1-2), wherein Ar 2 and Ar 3 are the same, and wherein Ar 2 and Ar 3 represent a substituted or unsubstituted naphthyl group.

5. An organic compound represented by the general formula (G1): wherein R 1 represents a substituted or unsubstituted naphthyl group, wherein R 2 represents a substituent represented by the general formula (G1-2); where α 3 represents an unsubstituted phenylene or an unsubstituted biphenylylene, where α 2 is the same as α 3 and wherein Ar 3 and Ar 2 represent unsubstituted naphthyl groups, and Among them, in the case of R 1 when having a substituent, the substituent is any one of an alkyl group having 1 to 12 carbon atoms, an unsubstituted phenyl group, an unsubstituted biphenyl group, an unsubstituted naphthyl group, an unsubstituted phenanthryl group, and an unsubstituted benzo[9,10]phenanthryl group.

6. An organic compound represented by the general formula (G1): wherein R 1 represents 2-naphthyl, wherein R 2 represents a substituent represented by the general formula (G1-2); wherein α 3 represents an unsubstituted phenylene or an unsubstituted biphenyldiyl, wherein α 2 is the same as α 3 ​ wherein Ar 3 and Ar 2 represent unsubstituted naphthyl groups.

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