Hole transport material, organic compound, light-emitting element and light-emitting device

Abstract

A hole transport material comprising an organic compound, wherein the organic compound is represented by the general formula (G1), where R 1 to R 8 independently represent hydrogen, a hydrocarbon group with 1 to 6 carbon atoms, a cyclic hydrocarbon group with 3 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group with 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group with 6 to 60 carbon atoms. where R 2 no amino group; where one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group with 3 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group with 1 to 6 carbon atoms, a hydrocarbon group with 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group with 6 to 60 carbon atoms, where Ar 1 and Ar 2 independently represent a substituted or unsubstituted aromatic hydrocarbon group with 6 to 60 carbon atoms or a group represented by the general formula (g2), where Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton where R 11 to R 18independently represent hydrogen, a hydrocarbon group with 1 to 6 carbon atoms, a cyclic hydrocarbon group with 3 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group with 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group with 6 to 60 carbon atoms, and where one of Z 1 and Z 2 bonded to a nitrogen atom in the general formula (g1) and the other being hydrogen, a cyclic hydrocarbon group with 3 to 6 carbon atoms, an alkoxy group with 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group with 1 to 6 carbon atoms, a hydrocarbon group with 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group with 6 to 60 carbon atoms.

Description

Technical area

[0001] An embodiment of the present invention relates to a hole transport material, an organic compound, a light-emitting element and a light-emitting device. State of the art

[0002] Light-emitting elements (organic EL elements) comprising organic compounds and utilizing electroluminescence (EL) have been increasingly used in practice. The basic structure of such a light-emitting element consists of an organic compound layer containing a light-emitting material (an EL layer) sandwiched between a pair of electrodes. Charge carriers are injected by applying a voltage to the element, and light emission can be obtained from the light-emitting material by utilizing the recombination energy of the charge carriers.

[0003] The light-emitting elements are self-luminous elements, and therefore, when used as pixels in a display, they offer advantages over liquid crystal displays, for example, such as high visibility and no need for backlighting, and they are suitable for flat-panel display elements. Another major advantage is that a display incorporating such light-emitting elements can also be manufactured as a thin and lightweight display. Furthermore, a very fast response time is also a feature.

[0004] In such light-emitting elements, light-emitting layers can be successively formed in a two-dimensional shape, thus achieving planar light emission. This feature is difficult to achieve with point light sources, such as incandescent lamps and LEDs, or linear light sources, such as fluorescent lamps. Consequently, these light-emitting elements also have great potential as planar light sources used in lighting devices and the like.

[0005] As described above, displays or lighting devices comprising light-emitting elements can be suitably used for a variety of electronic devices, and research and development of light-emitting elements has progressed with regard to higher efficiency or longer life.

[0006] An organic compound with an acceptor property is a material for a hole-injection layer used to promote the injection of charge carriers, especially holes, into an EL layer. The organic compound with an acceptor property can be easily deposited by evaporation, making it suitable for mass production and widely used. However, hole injection into an EL layer is difficult when the LUMO level of the organic compound with an acceptor property is far from the HOMO level of an organic compound contained in a hole-transport layer.In contrast, when the HOMO level of the organic compound contained in the hole-transporting layer is increased to be closer to the LUMO level of the organic compound having an acceptor property, the difference between the HOMO level of the light-emitting layer and the HOMO level of the organic compound contained in the hole-transporting layer is large, which makes it difficult to inject holes from the hole-transporting layer into a host material in the light-emitting layer even if holes can be injected into the EL layer.

[0007] In a structure disclosed in Patent Document 1, a hole-transport material whose HOMO level is between the HOMO level of a first hole-injection layer and the HOMO level of a host material is provided between a light-emitting layer and a first hole-transport layer in contact with the hole-injection layer. Other examples of hole-transport materials are disclosed in Patent Documents 2 to 11.

[0008] Although the properties of light-emitting elements have improved remarkably, the increased demands on some properties, including efficiency and durability, have not yet been satisfied. [References][Patent Documents] [Patent Document 1] WO 2011 / 065 136 A1 [Patent document 2] KR 10 2015 0 016 896 A [Patent document 3] EP 2 332 931 A2 [Patent document 4] EP 2 295 421 A1 [Patent document 5] KR 10 1 579 490 B1 [Patent document 6] EP 2 468 725 A1 [Patent Document 7] US 2014 / 0 183 500 A1 [Patent Document 8] US 2004 / 0 265 630 A1 [Patent Document 9] US 2004 / 0 021 136 A1 [Patent document 10] WO 2015 / 194 791 A2 [Patent Document 11] CN 1 04 761 535 A Revelation of the invention

[0009] In view of the foregoing, an object of an embodiment of the present invention is to provide a novel light-emitting element. Another object of an embodiment of the present invention is to provide a light-emitting element with a long lifetime. Another object of an embodiment of the present invention is to provide a light-emitting element with high emission efficiency. Another object of an embodiment of the present invention is to provide a novel organic compound. Another object of an embodiment of the present invention is to provide a novel organic compound having a hole-transport property. Another object of an embodiment of the present invention is to provide a novel hole-transport material.

[0010] Another object of an embodiment of the present invention is to provide a highly reliable light-emitting device. Another object of an embodiment of the present invention is to provide a light-emitting device that has low power consumption.

[0011] In the present invention, only one of the objects described above needs to be achieved.

[0012] One embodiment of the present invention is a hole transport material comprising an organic compound, wherein the organic compound is represented by the general formula (G1),wherein R 1 to R 8independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where R 2 is not an amino group; wherein one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, wherein Ar 1 and Ar 2 independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms or a group represented by the general formula (g2), wherein Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton, where R 11 to R 18independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and where one of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms.

[0013] Another embodiment of the present invention is an organic compound represented by the general formula (G1).

[0014] It should be noted that R 1 to R 8 in the general formula (G1) independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where R 2is not an amino group. One of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms.

[0015] It should be noted that Ar 1 and Ar 2in the general formula (g1) independently represent an unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted aromatic hydrocarbon group having 6 to 60 carbon atoms substituted by a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a dibenzofuranyl group or a benzonaphthofuranyl group, or a group represented by the general formula (g2), wherein Ar 1 and Ar 2 do not include a dibenzothiophene skeleton.

[0026]

[0016] It should be noted that R 11 to R 18in the general formula (g2) independently represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. One of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms.

[0017] Another embodiment of the present invention is an organic compound represented by the general formula (G1), wherein R 1 to R 8 independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and wherein one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, wherein Ar 1 and Ar 2 independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms or a group represented by the general formula (g2), wherein Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton, where R 11 to R 18independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where one of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and wherein the organic compound does not have two or more substituted or unsubstituted amine skeletons.

[0018] A further embodiment of the present invention is the organic compound having one of the above structures, wherein in the case where Ar 1 and Ar 2 each are an aromatic hydrocarbon group having 6 to 60 carbon atoms and comprise a substituent, the substituent comprising a benzonaphthofuranyl group and a dinaphthofuranyl group.

[0019] Another embodiment of the present invention is a light-emitting element comprising an anode, a cathode, and an EL layer. The EL layer is positioned between the anode and the cathode. The EL layer comprises the organic compound having one of the above structures.

[0020] Another embodiment of the present invention is a light-emitting element comprising an anode, a cathode, and an EL layer. The EL layer is positioned between the anode and the cathode and includes a light-emitting layer. The light-emitting layer comprises the organic compound having one of the above structures.

[0021] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the light-emitting layer further comprises a light-emitting material.

[0022] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the light-emitting layer further comprises a material having an electron-transport property.

[0023] Another embodiment of the present invention is a light-emitting element comprising an anode, a cathode, and an EL layer. The EL layer is positioned between the anode and the cathode. The EL layer comprises a light-emitting layer and a hole-transport layer. The hole-transport layer is positioned between the light-emitting layer and the anode. The hole-transport layer comprises the organic compound having one of the above structures.

[0024] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the EL layer further comprises a hole injection layer, the hole injection layer is in contact with the anode and the hole transport layer, and the hole injection layer comprises an organic compound having an acceptor property.

[0025] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the organic compound having an acceptor property is 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene.

[0026] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the hole-transport layer comprises a first layer, a second layer, and a third layer, the first layer is positioned between the hole-injection layer and the second layer, the third layer is positioned between the second layer and the light-emitting layer, the first layer is in contact with the hole-injection layer, the third layer is in contact with the light-emitting layer, the first layer comprises a first hole-transport material, the second layer comprises the organic compound, the third layer comprises a third hole-transport material, the light-emitting layer comprises a host material and a light-emitting material, the HOMO level of the organic compound is lower than the HOMO level of the first hole-transport material,the HOMO level of the host material is lower than the HOMO level of the organic compound, and the difference between the HOMO level of the organic compound and the HOMO level of the third hole-transporting material is less than or equal to 0.3 eV.

[0027] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the HOMO level of the first hole transport material is greater than or equal to -5.4 eV.

[0028] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the difference between the HOMO level of the first hole transport material and the HOMO level of the organic compound is less than or equal to 0.3 eV.

[0029] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the difference between the HOMO level of the organic compound and the HOMO level of the third hole transport material is less than or equal to 0.2 eV.

[0030] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the difference between the HOMO level of the first hole transport material and the HOMO level of the organic compound is less than or equal to 0.2 eV.

[0031] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the HOMO level of the light-emitting material is higher than the HOMO level of the host material.

[0032] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the HOMO level of the third hole transport material is lower than or equal to the HOMO level of the host material.

[0033] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the light-emitting material is a fluorescent substance.

[0034] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the light-emitting material emits blue fluorescence.

[0035] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the light-emitting material is a condensed aromatic diamine compound.

[0036] Another embodiment of the present invention is the light-emitting element having any of the above structures, wherein the light-emitting material is a diaminopyrene compound.

[0037] Another embodiment of the present invention is a light-emitting device comprising the light-emitting element having any of the above structures and a transistor or a substrate.

[0038] Note that the light-emitting device in this specification includes an image display device using a light-emitting element. The light-emitting device may include a module in which a light-emitting element is provided with a connector such as an anisotropic conductive film or a tape carrier package (TCP), a module in which a printed circuit board is provided at the end of a TCP, and a module in which an integrated circuit (IC) is directly mounted on a light-emitting element by a chip-on-glass (COG) method. The light-emitting device may also be included in a lighting device or the like.

[0039] According to one embodiment of the present invention, a novel light-emitting element can be provided. A light-emitting element with a long lifetime can be provided. A light-emitting element with high emission efficiency can be provided. A novel organic compound can be provided. A novel organic compound with a hole-transport property can be provided. A novel hole-transport material can be provided.

[0040] According to another embodiment of the present invention, a highly reliable light-emitting device can be provided. A light-emitting device with low power consumption can be provided.

[0041] It should be noted that the description of these effects does not preclude the existence of further effects. It is unnecessary to achieve all of the effects listed above in one embodiment of the present invention. Further effects will become apparent from and can be derived from the explanation of the description, the drawings, the claims, and the like. Short description of the drawings Fig. 1A to Fig. 1C are schematic views of light-emitting elements. Fig. 2A and Fig. 2B are conceptual diagrams of an active matrix light-emitting device. Fig. 3A and Fig. 3B are conceptual diagrams of an active matrix light-emitting device. Fig. Figure 4 is a conceptual diagram of an active matrix light-emitting device. Fig. 5A and Fig. 5B are conceptual diagrams of a passive matrix light-emitting device. Fig. 6A and Fig. 6B represent a lighting device. Fig. 7A to Fig. 7D represent electronic devices. Fig. 8 represents a light source device. Fig. 9 represents a lighting device. Fig. 10 represents a lighting device. Fig. 11 illustrates display devices and lighting devices in a vehicle. Fig. 12A to Fig. 12C represents an electronic device. Fig. 13A to Fig. 13C represent an electronic device. Fig. 14A and Fig. Show 14B 1 H NMR diagrams of BnfABP. Fig. Figure 15 shows an absorption spectrum and an emission spectrum of a solution of BnfABP. Fig. Figure 16 shows an absorption spectrum and an emission spectrum of a thin film of BnfABP. Fig. 17A and Fig. Show 17B 1 H NMR diagrams of BBABnf. Fig. Figure 18 shows an absorption spectrum and an emission spectrum of a solution of BBABnf. Fig. Figure 19 shows an absorption spectrum and an emission spectrum of a thin film of BBABnf. Fig. Figure 20 shows the luminance-current density characteristics of a light-emitting element 1. Fig. Figure 21 shows the power efficiency-luminance characteristics of the light-emitting element 1. Fig. Figure 22 shows the luminance-voltage characteristics of the light-emitting element 1. Fig. Figure 23 shows the current-voltage characteristics of the light-emitting element 1. Fig. Figure 24 shows the external quantum efficiency-luminance characteristics of the light-emitting element 1. Fig. 25 shows an emission spectrum of the light-emitting element 1. Fig. Figure 26 shows the time dependence of the normalized luminance of the light-emitting element 1. Fig. Figure 27 shows the luminance-current density characteristics of the light-emitting elements 2 and 3. Fig. Figure 28 shows the power efficiency-luminance characteristics of the light-emitting elements 2 and 3. Fig. Figure 29 shows the luminance-voltage characteristics of the light-emitting elements 2 and 3. Fig. Figure 30 shows the current-voltage characteristics of the light-emitting elements 2 and 3. Fig. Figure 31 shows the external quantum efficiency-luminance characteristics of the light-emitting elements 2 and 3. Fig. 32 shows emission spectra of the light-emitting elements 2 and 3. Fig. Figure 33 shows the time dependence of the normalized luminance of the light-emitting elements 2 and 3. Fig. 34A to Fig. 34D are cross-sectional views illustrating a method of manufacturing an EL layer. Fig. Figure 35 is a conceptual diagram illustrating a droplet ejector. Fig. 36A and Fig. Show 36B 1 H-NMR diagrams of BBABnf(6). Fig. Figure 37 shows an absorption spectrum and an emission spectrum of a solution of BBABnf(6). Fig. Figure 38 shows an absorption spectrum and an emission spectrum of a thin film of BBABnf(6). Fig. 39A and Fig. 39B show 1 H NMR diagrams of BBABnf(8). Fig. Figure 40 shows an absorption spectrum and an emission spectrum of a solution of BBABnf(8). Fig. Figure 41 shows an absorption spectrum and an emission spectrum of a thin film of BBABnf(8). Fig. Figure 42 shows the luminance-current density characteristics of the light-emitting elements 4 and 5. Fig. Figure 43 shows the power efficiency-luminance characteristics of the light-emitting elements 4 and 5. Fig. Figure 44 shows the luminance-voltage characteristics of the light-emitting elements 4 and 5. Fig. Figure 45 shows the current-voltage characteristics of the light-emitting elements 4 and 5. Fig. Figure 46 shows the external quantum efficiency-luminance characteristics of the light-emitting elements 4 and 5. Fig. Figure 47 shows emission spectra of the light-emitting elements 4 and 5. Fig. Figure 48 shows the time dependence of the normalized luminance of the light-emitting elements 4 and 5. Fig. Figure 49 shows the luminance-current density characteristics of the light-emitting elements 6 and 7. Fig. Figure 50 shows the power efficiency-luminance characteristics of the light-emitting elements 6 and 7. Fig. 51 shows the luminance-voltage characteristics of the light-emitting elements 6 and 7. Fig. 52 shows the current-voltage characteristics of the light-emitting elements 6 and 7. Fig. Figure 53 shows the external quantum efficiency-luminance characteristics of the light-emitting elements 6 and 7. Fig. Figure 54 shows emission spectra of the light-emitting elements 6 and 7. Fig. Figure 55 shows the luminance-current density characteristics of a light-emitting element 8. Fig. 56 shows the power efficiency-luminance characteristics of the light-emitting element 8. Fig. 57 shows the luminance-voltage characteristics of the light-emitting element 8. Fig. 58 shows the current-voltage characteristics of the light-emitting element 8. Fig. Figure 59 shows the external quantum efficiency-luminance characteristics of the light-emitting element 8. Fig. 60 shows an emission spectrum of the light-emitting element 8. Fig. 61 shows the time dependence of the normalized luminance of the light-emitting element 8. Best mode for carrying out the invention

[0042] Embodiments of the present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following description, and it will be understood by those skilled in the art that the modes and details can be changed in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the contents of the following embodiments. (Embodiment 1)

[0043] The lifetime of a light-emitting element comprising an organic material is, in some cases, particularly influenced by the properties of a hole-transporting material. In particular, the transport properties of the hole-transporting material have a significant influence on the lifetime, which varies significantly depending on the type of hole-transporting material.

[0044] The inventors of the present invention have found that a hole transport material comprising an organic compound having a substituted or unsubstituted benzonaphthofuran skeleton and a substituted or unsubstituted amine skeleton has a suitable transport property and contributes to an increase in the lifetime of a light-emitting element comprising the hole transport material.

[0045] In particular, the hole transport material comprises an organic compound, represented by the general formula (G1), where R 1 to R 8 independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where R 2 is not an amino group; wherein one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, wherein Ar 1 and Ar 2 independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms or a group represented by the general formula (g2), wherein Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton, where R 11 to R 18independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and where one of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms.

[0046] A light-emitting element that uses the hole-transport material for an EL layer can have a long lifetime.

[0047] Fig. 1A to Fig. 1C illustrate light-emitting elements of one embodiment of the present invention. The light-emitting elements of one embodiment of the present invention each include an anode 101, a cathode 102, and an EL layer 103 using the above-mentioned hole-transport material comprising the organic compound.

[0048] The EL layer 103 includes a light-emitting layer 113 and may also include a hole-transport layer 112. The light-emitting layer 113 includes a light-emitting material and a host material, and light is emitted from the light-emitting material in the light-emitting element of one embodiment of the present invention. The hole-transport material of one embodiment of the present invention may be included in the light-emitting layer 113 and / or the hole-transport layer 112.

[0049] It should be noted that Fig. 1A to Fig. 1C may additionally illustrate a hole injection layer 111, an electron transport layer 114, and an electron injection layer 115; however, the structure of the light-emitting element is not limited thereto.

[0050] The hole-transport material can also be used as a host material. Furthermore, the hole-transport material and an electron-transport material can be co-evaporated to form an exciplex. The exciplex, with a suitable emission wavelength, enables efficient energy transfer to the light-emitting material, resulting in a light-emitting element with high efficiency and a long lifetime.

[0051] The above hole-transport material has a good hole-transport property and is thus suitable for the hole-transport layer 112. In particular, the hole-transport material is preferably used in the case where the hole-injection layer 111 is provided between the hole-transport layer 112 and the anode 101 and comprises an organic compound having an acceptor property that promotes the injection of holes from the electrode.

[0052] In the case where hole injection is performed using the organic compound having an acceptor property, a compound contained in the hole-transport layer 112 in contact with the hole-injection layer 111 is preferably a hole-transport material having a relatively shallow HOMO level to promote the extraction of electrons by the organic compound having an acceptor property. However, holes cannot be easily injected into the light-emitting layer 113 from the hole-transport material having a relatively shallow HOMO level, and if the light-emitting layer 113 is formed in contact with the hole-transport layer 112 composed of the hole-transport material having a relatively shallow HOMO level, charge carriers are accumulated at their interface, resulting in a reduction in the lifetime and efficiency of the light-emitting element.Thus, a layer containing the organic compound of one embodiment of the present invention is provided between the light-emitting layer 113 and the hole-transporting material having a relatively flat HOMO level, in which case holes can be easily injected into the light-emitting layer and the lifetime and efficiency of the light-emitting element can be improved.

[0053] That is, the hole-transport layer 112 includes a first hole-transport layer 112-1 and a second hole-transport layer 112-2 from the hole-injection layer 111 side. The first hole-transport layer 112-1 contains a first hole-transport material, while the second hole-transport layer 112-2 contains the hole-transport material of one embodiment of the present invention. The HOMO level of the hole-transport material of one embodiment of the present invention is deeper than the HOMO level of the first hole-transport material, resulting in a light-emitting element with a long lifetime and high efficiency. Note that the HOMO level of the first hole-transport material is preferably greater than or equal to -5.4 eV, in which case electrons can be easily extracted from the organic compound having an acceptor property.

[0054] The difference between the HOMO level of the first hole transport material and the HOMO level of the hole transport material of the present invention is preferably less than or equal to 0.3 eV, more preferably less than or equal to 0.2 eV, in which case holes can be easily injected from the first hole transport layer 112-1 into the second hole transport layer 112-2.

[0055] The hole-transport layer 112 may further comprise a third hole-transport layer 112-3 between the second hole-transport layer 112-2 and the light-emitting layer, and the third hole-transport layer 112-3 may contain a third hole-transport material. In this case, the HOMO level of the third hole-transport material is preferably lower than the HOMO level of the hole-transport material of an embodiment of the present invention contained in the second hole-transport layer 112-2, and the difference in the HOMO level is preferably less than or equal to 0.3 eV, more preferably less than or equal to 0.2 eV.

[0056] The HOMO level of the third hole transport material is preferably lower than or equal to the HOMO level of the host material, in which case holes are transported appropriately to the light-emitting layer to increase the lifetime and efficiency.

[0057] It should be noted that in the case where the HOMO level of the light-emitting material is shallower (higher) than the HOMO level of the host material, the proportion of holes injected into the light-emitting material increases depending on the position of the HOMO level of the hole-transport layer, and further, the holes are trapped in the light-emitting material, which may lead to a reduced lifetime due to an unevenly distributed light-emitting region. The light-emitting element structure of the present invention is preferably applied in such a case, for example, to a blue fluorescent element.In particular, the structure of the present invention can be preferably used for an aromatic diamine compound emitting excellent blue fluorescence, more preferably for a pyrenediamine compound and the like, resulting in obtaining a light-emitting element having excellent lifetime, efficiency and chromaticity.

[0058] Next, examples of specific structures and materials of the aforementioned light-emitting element will be described. As described above, the light-emitting element of one embodiment of the present invention includes the EL layer 103 positioned between the pair of electrodes (the anode 101 and the cathode 102) and having a plurality of layers. In the EL layer 103, at least the hole-injection layer 111, the hole-transport layer 112, and the light-emitting layer 113 are provided from the anode 101 side.

[0059] There is no particular limitation on other layers included in the EL layer 103, and various layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a charge blocking layer, an exciton blocking layer, and a charge generation layer may be used.

[0060] The anode 101 is preferably formed using a metal, an alloy, or a conductive compound with a high work function (particularly, a work function of 4.0 eV or more), a mixture thereof, or the like. Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide, indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). Such conductive metal oxide films are generally formed by a sputtering method, but may also be formed by using a sol-gel method or the like. In one example of the formation method, indium oxide-zinc oxide is deposited by a sputtering method using a target obtained by adding 1 wt% to 20 wt% of zinc oxide to indium oxide.Furthermore, an indium oxide film containing tungsten oxide and zinc oxide (IWZO) can be formed by a sputtering method using a target in which 0.5 wt% to 5 wt% of tungsten oxide and 0.1 wt% to 1 wt% of zinc oxide are added to indium oxide. Alternatively, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), a nitride of a metal material (e.g., titanium nitride), or the like can be used. Graphene can also be used. Note that when a composite material described below is used for a layer in contact with the anode 101 in the EL layer 103, an electrode material can be selected without considering its work function.

[0061] Two types of multilayer structure of the EL layer 103 are described: the structure shown in Fig. 1A and includes the electron transport layer 114 and the electron injection layer 115 in addition to the hole injection layer 111, the hole transport layer 112 and the light emitting layer 113; and the structure shown in Fig. 1B and includes the electron-transport layer 114, the electron-injection layer 115, and a charge-generation layer 116 in addition to the hole-injection layer 111, the hole-transport layer 112, and the light-emitting layer 113. Materials for forming each layer will be described in detail below.

[0062] The hole-injection layer 111 contains a substance having an acceptor property. The structure of one embodiment of the present invention is preferably used in the case where an organic compound having an acceptor property is used. As the organic compound having an acceptor property, a compound containing an electron-withdrawing group (a halogen group or a cyano group) such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, or 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN) can be used. The organic compound having an acceptor property is preferably a compound in which electron-withdrawing groups are bonded to a condensed aromatic ring containing a plurality of heteroatoms, such as HAT-CN, because it is thermally stable.The organic compound with an acceptor property can extract electrons from a neighboring hole transport layer (or hole transport material) by applying an electric field.

[0063] In the case where the organic compound having an acceptor property is not used for the hole-injection layer 111, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, or the like can be used as a substance having an acceptor property. Alternatively, the hole-injection layer 111 can be formed using a phthalocyanine-based compound such as phthalocyanine (abbreviation: H2Pc) or copper phthalocyanine (abbreviation: CuPc), an aromatic amine compound such as phthalocyanine (abbreviation: CuPc), or a phthalocyanine-based compound such as phthalocyanine (abbreviation: H2Pc). B. 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) or N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1, 1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), or a high molecular weight compound, such as B. poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS).

[0064] Alternatively, a composite material in which a substance with a hole-transporting property contains an acceptor substance can be used for the hole-injection layer 111. By using a composite material in which a substance with a hole-transporting property contains an acceptor substance, a material for forming an electrode can be selected without considering its work function. In other words, in addition to a material with a high work function, a material with a low work function can also be used for the anode 101. Examples of the acceptor substance include an organic compound with an acceptor property, such as 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, or 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), and a transition metal oxide. Alternatively, an oxide of a metal from groups 4 to 8 of the periodic table can be used.As the oxide of a metal from Groups 4 to 8 of the Periodic Table, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, rhenium oxide, or the like are preferred due to their high electron-accepting property. Among these, molybdenum oxide is particularly preferred because of its stability in air, low hygroscopicity, and ease of handling.

[0065] As a substance with a hole-transporting property used for the composite material, various organic compounds, such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and high-molecular compounds (e.g., oligomers, dendrimers, or polymers), can be used. It should be noted that the substance with a hole-transporting property used for the composite material is preferably a substance with a hole mobility of 10 -6 cm 2 / Vs or higher. The organic compounds that can be used as a substance having a hole-transporting property in the composite material are specifically indicated below.

[0066] Examples of the aromatic amine compounds that can be used for the composite material include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD) and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B).Specific examples of the carbazole derivatives include 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenylanthracen-9-yl)phenyl]-9H-carbazole (abbreviation: CzPA) and 1,4-Bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert-butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-Tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-Bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-blanthryl, anthracene, tetracene, rubrene, perylene and 2,5,8,11-Tetra(tert-butyl)perylene. Pentacene, coronene, or the like can also be used.The aromatic hydrocarbon may have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA). Note that the organic compound of one embodiment of the present invention can also be used. In this case, F6-TCNNQ is preferably used as the acceptor substance.

[0067] A high molecular weight compound such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N'-(4-{N-[4-(-4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA) or poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: poly-TPD) can also be used.

[0068] By providing a hole injection layer, a high hole injection property can be achieved, resulting in a light-emitting element being able to be driven at a low voltage.

[0069] It should be noted that the hole-injection layer can be formed solely from the above-described acceptor material or from a combination of the above-described acceptor material and another material. In this case, the acceptor material extracts electrons from the hole-transport layer, allowing holes to be injected into the hole-transport layer. The acceptor material transports the extracted electrons to the anode.

[0070] By providing the hole-injection layer 111, a high hole-injection property can be achieved, resulting in the ability to drive a light-emitting element at a low voltage. Furthermore, the organic compound with an acceptor property is easy to use because it is easily deposited by vapor deposition.

[0071] The hole transport layer 112 contains a hole transport material. The hole transport material preferably has a hole mobility of 1 × 10 -6 cm 2 / Vs or higher. The hole-transport layer 112 preferably comprises the hole-transport material of one embodiment of the present invention, in which case a light-emitting element with a long lifetime and high efficiency can be provided.

[0072] Specifically, when the organic compound having an acceptor property is used for the hole injection layer 111, at least the hole injection layer 111 is composed of two layers, that is, a first and a second hole transport layer, a first hole transport material having a relatively flat HOMO level is used for the first hole injection layer, and the hole transport material of one embodiment of the present invention is used for the second hole transport layer; as a result, a light-emitting element having a long lifetime and high efficiency can be provided.

[0073] Although the difference between the LUMO level of the organic compound with an acceptor property and the HOMO level of the first hole-transporting material is not particularly limited because it depends on the strength of the acceptor property of the organic compound with an acceptor property, holes can be injected when the difference between the levels is less than or equal to approximately 1 eV. Since the LUMO level of HAT-CN is calculated to be -4.41 eV by cyclic voltammetry measurement, in the case where HAT-CN is used as the organic compound with an acceptor property, the HOMO level of the first hole-transporting material is preferably greater than or equal to -5.4 eV. Note that if the HOMO level of the first hole-transporting material is too high, the hole-injection property for the second hole-transporting material deteriorates.Furthermore, using a material with a HOMO level higher than -5 eV as the first hole-transport material results in a disadvantage, since the work function of an anode, such as ITO, is approximately -5 eV. Therefore, the HOMO level of the first hole-transport material is preferably less than or equal to -5.0 eV.

[0074] A third hole-transport layer may be formed between the second hole-transport layer and the light-emitting layer. The third hole-transport layer comprises a third hole-transport material.

[0075] The first to third hole-transport layers have been described above and will not be described again. Note that the hole-transport material contained in each hole-transport layer can be selected from the aforementioned materials having hole-transport properties or other materials having hole-transport properties so that the layers have an appropriate relationship with each other.

[0076] The light-emitting layer 113 includes the host material and the light-emitting material. Fluorescent materials, phosphorescent materials, substances exhibiting thermally activated delayed fluorescence (TADF), or other light-emitting materials can be used as the light-emitting material. Furthermore, the light-emitting layer 113 can be a single layer or comprise a plurality of layers containing different light-emitting materials. Note that one embodiment of the present invention is more preferably used in the case where the light-emitting layer 113 emits fluorescence, particularly blue fluorescence.

[0077] Examples of the material that can be used as the fluorescent substance in the light-emitting layer 113 are described below. Fluorescent substances other than those listed below may also be used.

[0078] Examples of the fluorescent substance include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]-pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-Bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-Diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), Perylene, 2,5,8,11-Tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N'-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N,N-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-Octaphenyldibenzo[g,p]chrysen-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-Bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-Diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-Bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-Bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-Triphenylanthracene-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-Diphenylquinacridone (abbreviation: DPQd), Rubrene, 5,12-Bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT),2-(2-{2-[4-(Dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-Methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-Tetrakis(4-methylphenyl)tetracen-5,11-diamine (abbreviation: p-mPhTD), 7,14-Diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-Isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]chino lizin-9-yl)ethenyl]-4H-pyran-4-ylidene} propandinitrile (abbreviation: DCJTI), 2-{2-tert-Butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinol izin-9-yl)ethenyl]-4H-pyran-4-ylidene} propandinitrile (abbreviation: DCJTB), 2-(2,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-Bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]c hinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene} propanedinitrile (abbreviation: BisDCJTM) and N,N'-Diphenyl-N,N'-(1,6-pyrenediyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03). Condensed aromatic diamine compounds, typically pyrenediamine compounds, such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are particularly preferred due to their high hole-trapping properties, high emission efficiency, and high reliability.

[0079] Examples of the material that can be used as the phosphorescent substance in the light-emitting layer 113 are as follows.

[0080] The examples include organometallic iridium complexes with 4H-triazole frameworks, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]) and tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]); organometallic iridium complexes with 1H-triazole frameworks, such as B. Tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]) and Tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]); organometallic iridium complexes with imidazole frameworks, such asfac-Tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]); and organometallic iridium complexes in which a phenylpyridine derivative with an electron-withdrawing group is a ligand, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C. 2' ]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' ]iridium(III) picolinate (abbreviation: Flrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2'} iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]) and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' ]iridium(III) acetylacetonate (abbreviation: Flr(acac)). These are compounds that emit blue phosphorescence and exhibit an emission peak between 440 nm and 520 nm.

[0081] Further examples include organometallic iridium complexes with pyrimidine frameworks, such as: B. Tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), Tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (Acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (Acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (Acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (Acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]) and (Acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]); organometallic iridium complexes with pyrazine frameworks, such as(Acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]); organometallic iridium complexes with pyridine frameworks, such as tris(2-phenylpyridinato-N,C 2' )iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2' )iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2' )iridium(III) (abbreviation: [Ir(pq)3]) and bis(2-phenylquinolinato-N,C 2'iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]); and rare earth metal complexes, such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). These are mainly compounds that emit green phosphorescence and exhibit an emission peak at 500 nm to 600 nm. It should be noted that organometallic iridium complexes with pyrimidine frameworks exhibit very high reliability and emission efficiency and are therefore particularly preferred.

[0082] Further examples include organometallic iridium complexes with pyrimidine frameworks, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]) and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]); organometallic iridium complexes with pyrazine frameworks, such as B. (Acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]) and (Acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]); organometallic iridium complexes with pyridine frameworks, such as tris(1-phenylisoquinolinato-N,C 2' )iridium(III) (abbreviation: [Ir(piq)3]) and bis(1-phenylisoquinolinato-N,C 2')iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]); platinum complexes, such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: PtOEP); and rare earth metal complexes, such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]). These are compounds that emit red phosphorescence and exhibit an emission peak at 600 nm to 700 nm. Furthermore, organometallic iridium complexes with pyrazine frameworks can emit red light with favorable chromaticity (color type).

[0083] In addition to the above phosphorescent compounds, known phosphorescent materials can also be selected and used.

[0084] Examples of the TADF material include a fullerene, a derivative thereof, acridine, a derivative thereof, an eosin derivative, and a metal-containing porphyrin, such as a porphyrin containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of the metal-containing porphyrin include a protoporphyrin-tin fluoride complex (SnF2(Proto IX)), a mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), a hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), a coproporphyrin-tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), an octaethylporphyrin-tin fluoride complex (SnF2(OEP)), an etioporphyrin-tin fluoride complex (SnF2(Etio I)), and an octaethylporphyrin-platinum chloride complex (PtCl2(OEP)), which are represented by the following structural formulas.

[0085] Alternatively, a heterocyclic compound comprising both a π-electron-rich heteroaromatic ring and a π-electron-poor heteroaromatic ring, such as B. 2-(Biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-Diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 9-[4-(4,6-Diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzPTzn), 2-[4-(10H-Phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-Phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS) or 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), which are represented by the following structural formulas, can be used.The heterocyclic compound is preferred because it has the π-electron-rich heteroaromatic ring and the π-electron-poor heteroaromatic ring; therefore, the electron-transport property and the hole-transport property are high. Note that a substance in which the π-electron-rich heteroaromatic ring is directly bonded to the π-electron-poor heteroaromatic ring is particularly preferred because both the donor property of the π-electron-rich heteroaromatic ring and the acceptor property of the π-electron-poor heteroaromatic ring are increased, and the energy difference between the S1 level and the T1 level becomes small, whereby thermally activated delayed fluorescence can be obtained with high efficiency. Note that an aromatic ring to which an electron-withdrawing group, such as phenyl group, is attached is preferable. B. a cyano group, can be used instead of the π-electron-deficient heteroaromatic ring.

[0086] Various charge transport materials can be used as the host material of the light-emitting layer, such as materials with an electron transport property and materials with a hole transport property.

[0087] The following are examples of materials with a hole transport property: Compounds with aromatic amine frameworks, such as4,4'-Bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-Bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-Bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-Phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-Phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-Diphenyl-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-Di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-Dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF) and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF); compounds with carbazole skeletons, such as1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP) and 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP); compounds with thiophene scaffolds, such as B. 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV); and compounds with furan skeletons, such as 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl} dibenzofuran (abbreviation: mmDBFFLBi-II).Among the above materials, the compounds with aromatic amine frameworks and the compounds with carbazole frameworks are preferred because these compounds are highly reliable, have high hole transport property, and contribute to a reduction in the driving voltage.

[0088] The following are examples of materials with electron transport properties: metal complexes, such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ); heterocyclic compounds with polyazole backbones, such as2-(4-Biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI) and 2-[3-(Dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II); heterocyclic compounds with diazine skeletons, such as2-[3-(Dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm) and 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II); and heterocyclic compounds with pyridine skeletons, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB). Among the above materials, heterocyclic compounds with diazine skeletons and heterocyclic compounds with pyridine skeletons are very reliable and preferred.In particular, heterocyclic compounds with diazine scaffolds (pyrimidine scaffolds or pyrazine scaffolds) exhibit high electron transport properties and contribute to a reduction in the drive voltage.

[0089] In the case where a fluorescent substance is used as a light-emitting material, a material having an anthracene skeleton is preferably used as the host material. Using a substance having an anthracene skeleton as the host material for the fluorescent substance makes it possible to obtain a light-emitting layer having high emission efficiency and high durability. Most materials having an anthracene skeleton have a low HOMO level; thus, such a material can be preferably used in an embodiment of the present invention. Among the substances having an anthracene skeleton, a substance having a diphenylanthracene skeleton, particularly a substance having a 9,10-diphenylanthracene skeleton, is chemically stable and is thus preferably used as the host material.The host material preferably has a carbazole framework because the hole injection and transport properties are enhanced; more preferably, the host material has a benzocarbazole framework in which a benzene ring is further condensed to carbazole, because the HOMO level thereof is approximately 0.1 eV shallower than that of carbazole, thus allowing holes to easily penetrate the host material. Specifically, the host material preferably comprises a dibenzocarbazole framework because the HOMO level thereof is approximately 0.1 eV shallower than that of carbazole, thus allowing holes to easily penetrate the host material, improving the hole transport property, and increasing heat resistance. Therefore, a substance having both a 9,10-diphenylanthracene framework and a carbazole framework (or a benzocarbazole or dibenzocarbazole framework) is further preferable as the host material.It should be noted that in view of the hole injection and hole transport properties described above, a benzofluorene framework or a dibenzofluorene framework may be used instead of a carbazole framework. Examples of such a substance include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA) and 9-Phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA). In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices due to their excellent properties.

[0090] It should be noted that the light-emitting element of one embodiment of the present invention is particularly preferably used as a light-emitting element that emits blue fluorescence.

[0091] Note that the host material may be a mixture of several types of substances. In the case of using a mixed host material, it is preferable to mix a material having an electron-transport property with a material having a hole-transport property. By mixing the material having an electron-transport property with the material having a hole-transport property, the transport property of the light-emitting layer 113 can be easily adjusted, and a recombination range can be easily controlled. The ratio of the material having a hole-transport property to the material having an electron-transport property can be 1:9 to 9:1.

[0092] An exciplex can be formed by these mixed materials. The combination of these materials is preferably selected to form an exciplex that emits light at a wavelength that overlaps with that of the lowest energy absorption band of the light-emitting material. In this case, energy is easily transferred, light emission can be achieved efficiently, and the driving voltage is reduced.

[0093] The electron-transport layer 114 is a layer containing a substance with electron-transport properties. As the substance with electron-transport properties, one of the substances with electron-transport properties listed above that can be used as a host material can be used.

[0094] For the electron injection layer 115 between the electron transport layer 114 and the cathode 102, a layer containing an alkali metal, an alkaline earth metal, or a compound thereof, such as lithium fluoride (LiF), cesium fluoride (CsF), or calcium fluoride (CaF2), can be used. For example, an electride or a layer formed using a substance with an electron transport property and containing an alkali metal, an alkaline earth metal, or a compound thereof can be used as the electron injection layer 115. Examples of the electride include a substance in which electrons are added at a high concentration to calcium oxide-alumina.

[0095] Instead of the electron injection layer 115, the charge generation layer 116 may be provided ( Fig. 1B). The charge generation layer 116 denotes a layer capable of injecting holes into a layer in contact with the cathode side of the charge generation layer 116 and electrons into a layer in contact with its anode side upon application of a potential. The charge generation layer 116 includes at least one p-type layer 117. The p-type layer 117 is preferably formed using one of the composite materials cited above as examples of materials that can be used for the hole injection layer 111. The p-type layer 117 can be formed by superposing a film containing the above-described acceptor material as a material contained in the composite material and a film containing a hole-transport material.When a potential is applied to the p-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the cathode 102, which serves as the cathode; in this way, the light-emitting element operates.

[0096] It should be noted that the charge generation layer 116 preferably includes, in addition to the p-type layer 117, an electron relay layer 118 and / or an electron injection buffer layer 119.

[0097] The electron relay layer 118 contains at least the substance having an electron-transport property and has a function of preventing interaction between the electron injection buffer layer 119 and the p-type layer 117 and a function of smoothly transferring electrons. The LUMO level of the substance having an electron-transport property contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor substance in the p-type layer 117 and the LUMO level of a substance in a layer of the electron-transport layer 114 that is in contact with the charge generation layer 116. As a concrete value of the energy level, the LUMO level of the substance having an electron transport property contained in the electron relay layer 118 is preferably higher than or equal to -5.0 eV, more preferably higher than or equal to -5.0 eV and lower than or equal to -3.0 eV.It should be noted that as a substance having an electron-transport property in the electron-transmitting layer 118, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0098] A substance with a high electron injection property can be used for the electron injection buffer layer 119. For example, an alkali metal, an alkaline earth metal, a rare earth metal, or a compound thereof (e.g., an alkali metal compound (including an oxide such as lithium oxide, a halide, and a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, and a carbonate), or a rare earth metal compound (including an oxide, a halide, and a carbonate)) can be used.

[0099] In the case where the electron injection buffer layer 119 contains the substance having an electron transport property and a donor substance, an organic compound such as tetrathianaphthacene (abbreviation: TTN), nickelocene, or decamethylnickelocene can be used as the donor substance, and an alkali metal, an alkaline earth metal, a rare earth metal, and a compound of the above metal (e.g., an alkali metal compound (including an oxide such as lithium oxide, a halide, and a carbonate such as lithium carbonate or cesium carbonate), an alkaline earth metal compound (including an oxide, a halide, and a carbonate), and a rare earth metal compound (including an oxide, a halide, and a carbonate)).Note that, as a substance having an electron-transport property, a material similar to the above-described material used for the electron-transport layer 114 may be used.

[0100] For the cathode 102, for example, metals, alloys, electrically conductive compounds, and mixtures thereof that have a low work function (particularly, a work function of 3.8 eV or less) can be used. Specific examples of such a cathode material include elements belonging to Group 1 or 2 of the Periodic Table, such as alkali metals (e.g., lithium (Li) and cesium (Cs)), magnesium (Mg), calcium (Ca), and strontium (Sr), alloys thereof (e.g., MgAg and AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys thereof. However, when the electron injection layer is provided between the cathode 102 and the electron transport layer, various conductive materials such as silicon dioxide (SiO) and lithium hydroxide (LiH) can be used for the cathode 102. B. Al, Ag, ITO or indium oxide-tin oxide containing silicon or silicon oxide can be used regardless of the work function.Films of these conductive materials can be formed by a dry process such as a vacuum evaporation process or a sputtering process, an inkjet process, a spin-coating process, or the like. Furthermore, the films can be formed by a wet process using a sol-gel process or by a wet process using a paste of a metal material.

[0101] Various methods can be used to form the EL layer 103, regardless of whether it is a dry process or a wet process. For example, a vacuum evaporation method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method, or a spin-coating method can be used.

[0102] The electrodes or layers described above can be formed by different methods.

[0103] The structure of the layers provided between the anode 101 and the cathode 102 is not limited to the structure described above. Preferably, a light-emitting region where holes and electrons recombine is located away from the anode 101 and the cathode 102, so that quenching due to the proximity between the light-emitting region and a metal used for electrodes and charge injection layers can be prevented.

[0104] Further, in order to suppress energy transfer from an exciton generated in the light-emitting layer, it is preferable that the hole transport layer and the electron transport layer in contact with the light-emitting layer 113, particularly a carrier transport layer closer to the recombination region in the light-emitting layer 113, be formed using a material having a larger band gap than the light-emitting material of the light-emitting layer or the light-emitting material contained in the light-emitting layer.

[0105] Next, an embodiment of a light-emitting element having a structure in which a plurality of light-emitting units are stacked one on top of the other (this type of light-emitting element is also called a multi-layer element or a tandem element) will be described with reference to Fig. 1C. In this light-emitting element, a plurality of light-emitting units are provided between an anode and a cathode. Each light-emitting unit has substantially the same structure as the EL layer 103 shown in Fig. 1A. In other words, the light-emitting element that is Fig. 1C is a light-emitting element comprising a plurality of light-emitting units; each of the light-emitting elements shown in Fig. 1A and Fig. 1B is a light-emitting element comprising a single light-emitting unit.

[0106] In Fig. 1C, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between an anode 501 and a cathode 502, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 correspond to the anode 101 and the cathode 102, respectively, in Fig. 1A, and the materials used in the description of the Fig. 1A may be used. Furthermore, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures.

[0107] The charge generation layer 513 has a function of injecting electrons into one of the light-emitting units and injecting holes into the other of the light-emitting units when a voltage is applied between the anode 501 and the cathode 502. That is, in Fig. 1C, the charge generation layer 513 injects electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512 when a voltage is applied such that the potential of the anode is higher than the potential of the cathode.

[0108] The charge generation layer 513 preferably has a structure similar to that of the Fig. 1B. Since the composite material of an organic compound and a metal oxide is superior in terms of charge injection property and charge transport property, low-voltage driving or low-current driving can be achieved. Note that when a surface of a light-emitting unit on the anode side is in contact with the charge generation layer 513, the charge generation layer 513 can also serve as a hole injection layer of the light-emitting unit; therefore, a hole injection layer does not necessarily need to be formed in the light-emitting unit.

[0109] In the case where the electron injection buffer layer 119 is provided, the electron injection buffer layer 119 serves as an electron injection layer in the light-emitting unit on the anode side; therefore, the light-emitting unit on the anode side does not necessarily need an electron injection layer.

[0110] The light-emitting element, which has two light-emitting units, is identified by Fig. 1C; however, the present invention can be equally applied to a light-emitting element in which three or more light-emitting units are stacked. When a plurality of light-emitting units divided by the charge generation layer 513 are arranged between a pair of electrodes, as in the light-emitting element of this embodiment, it is possible to provide an element with a long lifetime that can emit light with high luminance while keeping the current density low. In addition, a light-emitting device that consumes little power and can be driven at a low voltage can be manufactured.

[0111] Furthermore, when the emission colors of the light-emitting units differ from each other, light emission of a desired color can be obtained from the light-emitting element as a whole. For example, in a light-emitting element having two light-emitting units, the emission colors of the first light-emitting unit may be red and green, and the emission color of the second light-emitting unit may be blue, so that the light-emitting element can emit white light as a whole.

[0112] The above-described electrodes and layers, such as the EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer, can be deposited by a method such as an evaporation method (including a vacuum evaporation method), a droplet ejection method (also referred to as an inkjet method), a coating method, or a gravure printing method. A low-molecular material, a medium-molecular material (including an oligomer and a dendrimer), or a high-molecular material can be included in the layers and electrodes.

[0113] Here, a method of forming an EL layer 786 by a droplet ejection method is described based on Fig. 34A to Fig. 34D described. Fig. 34A to Fig. 34D are cross-sectional views illustrating the process of forming the EL layer 786.

[0114] First, a conductive film 772 is formed over an insulating planarization film 770, and an insulating film 730 is formed to cover a part of the conductive film 772 (see Fig. 34A).

[0115] Then, a droplet 784 is ejected from a droplet ejector 783 onto an exposed portion of the conductive film 772, which is an opening of the insulating film 730, so that a layer 785 containing a composition is formed. The droplet 784 is a composition containing a solvent and is attached to the conductive film 772 (see Fig. 34B).

[0116] It should be noted that the step of ejecting the droplet 784 may be performed under reduced pressure.

[0117] Next, the solvent is removed from the composition-containing layer 785, and the resulting layer is solidified to form the EL layer 786 (see Fig. 34C).

[0118] The solvent can be removed by drying or heating.

[0119] Next, a conductive film 788 is formed over the EL layer 786; thus, a light-emitting element 782 is formed (see Fig. 34D).

[0120] When the EL layer 786 is formed by a droplet ejection method as described above, the composition can be selectively ejected; thus, the loss of material can be reduced. Furthermore, no lithography process or the like is required for forming, which simplifies the process and reduces costs.

[0121] The droplet ejection method described above is a general term for a means for ejecting droplets, such as a nozzle having an orifice for ejecting a composition or a head having one nozzle or a plurality of nozzles.

[0122] Next, a droplet ejector used for the droplet ejection method is described by Fig. 35 described. Fig. 35 is a conceptual diagram illustrating a droplet ejector 1400.

[0123] The droplet ejection device 1400 includes a droplet ejection means 1403. The droplet ejection means 1403 is further equipped with a head 1405, a head 1412, and a head 1416.

[0124] The heads 1405, 1412 and 1416 are connected to a control means 1407 controlled by a computer 1410; accordingly, a pre-programmed pattern can be drawn.

[0125] The drawing can be performed at a time, for example, based on a mark 1411 formed over a substrate 1402. Alternatively, the reference point can be determined based on an outer edge of the substrate 1402. Here, the mark 1411 is captured by an imaging means 1404 and converted into a digital signal by an image processing means 1409. The digital signal is recognized by the computer 1410, and then a control signal is generated and transmitted to the control means 1407.

[0126] An image sensor or the like can be used for the imaging means 1404, using a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Note that information about a pattern to be formed over the substrate 1402 is stored in a storage medium 1408, and a control signal based on the information is transmitted to the control means 1407, so that the heads 1405, 1412, and 1416 of the droplet ejection means 1403 can each be controlled separately. A material to be ejected is supplied to the heads 1405, 1412, and 1416 from the material supply sources 1413, 1414, and 1415, respectively, through pipes.

[0127] In the head 1405, a space to be filled with a liquid material, represented by a dashed line 1406, and a nozzle serving as an ejection opening are provided. Although not shown, the internal structures of the heads 1412 and 1416 are similar to the internal structure of the head 1405. If the heads 1405 and 1412 have different nozzle sizes, different materials with different widths can be ejected simultaneously. Each head can eject a plurality of light-emitting materials for drawing. In the case of drawing over a large area, the same material can be ejected from a plurality of nozzles simultaneously to improve throughput. When a large substrate is used, the heads 1405, 1412, and 1416 can eject the substrate in the directions indicated by the arrows X, Y, and Z in Fig. 35 directions, and the area in which a pattern is drawn can be freely set. Therefore, a plurality of identical patterns can be drawn over a substrate.

[0128] The composition ejection step may be performed under reduced pressure. A substrate may also be heated when the composition is ejected. After the composition is ejected, drying and / or baking are performed. Both drying and baking are heat treatments; however, they differ in purpose, temperature, and time. The drying step and the baking step are each performed under normal pressure or reduced pressure, by laser light irradiation, rapid thermal annealing, heating using a heating furnace, or the like. Note that there is no particular limitation on the timing and number of heat treatments. The temperature for adequately performing the drying and baking steps depends on the materials of the substrate and the properties of the composition.

[0129] In the above manner, the EL layer 786 can be formed with the droplet ejection device.

[0130] In the case where the EL layer 786 is formed with the droplet ejection device, a hole-transporting layer can be formed by a wet method using a composition in which the hole-transporting material of the present invention is dissolved in a solvent. In this case, the following various organic solvents can be used to form a coating composition: benzene, toluene, xylene, mesitylene, tetrahydrofuran, dioxane, ethanol, methanol, n-propanol, isopropanol, n-butanol, t-butanol, acetonitrile, dimethyl sulfoxide, dimethylformamide, chloroform, methylene chloride, carbon tetrachloride, ethyl acetate, hexane, cyclohexane, and the like. In particular, low-polar benzene derivatives such as benzene derivatives are preferably used.Benzene, toluene, xylene, and mesitylene are used because a solution with an appropriate concentration can be obtained and deterioration of the hole-transporting material of the present invention contained in the ink due to oxidation or the like can be prevented. Furthermore, in order to obtain a uniform film or a film with a uniform thickness, a solvent having a boiling point of 100°C or higher is preferably used, and toluene, xylene, or mesitylene is more preferably used.

[0131] It should be noted that the above structure may be appropriately combined with any of the structures of this embodiment and the other embodiments. (Embodiment 2)

[0132] In this embodiment, an organic compound of one embodiment of the present invention is described.

[0133] Some of the organic compounds described in Embodiment 1 that can be used as the second hole-transport material are novel compounds and thus embodiments of the present invention. The organic compound of one embodiment of the present invention is described below.

[0134] The organic compound of one embodiment of the present invention is represented by the general formula (G1).

[0135] It should be noted that R 1 to R 8in the general formula (G1) independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where R 2 is not an amino group or wherein the organic compound does not have two or more substituted or unsubstituted amine skeletons.

[0136] Specific examples for R 1 to R 8 in the general formula (G1) are represented by formulas (1-1) to (1-40). In the case where R 1 to R 8each represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, aromatic hydrocarbons in a skeleton of a substituent are represented by the formulas (2-1) to (2-13). Note that there is no limitation on the substitution site of the aromatic hydrocarbon represented by the formulas (2-1) to (2-13), and a plurality of aromatic hydrocarbon groups may be bonded to each other to form a skeleton.

[0137] It should be noted that in the case where R 1 to R 8are each an aromatic hydrocarbon group comprising a substituent, the substituent may be a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a dibenzofuranyl group, or a benzonaphthofuranyl group. In the case where R 1 to R 8are each an aromatic hydrocarbon group comprising a substituent, and the substituent is a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen or a haloalkyl group having 1 to 6 carbon atoms, are specific structural examples of R 1 to R 8 the same as those represented by formulas (1-1) to (1-40) used above as specific examples of R 1 to R 8 have been shown.

[0138] In the case where R 1 to R 8are each an aromatic hydrocarbon group comprising a substituent, and the substituent is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a dibenzofuranyl group or a benzonaphthofuranyl group, specific structural examples of R 1 to R 8 represented by formulas (1-41) to (1-81). For all substituents represented by formulas (1-41) to (1-81), there is no restriction regarding the site of substitution.

[0139] One of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. Specific examples are the same as those for the substituents R 1 to R 8 .

[0140] It should be noted that Ar 1 and Ar 2 in the general formula (g1) do not comprise a dibenzothiophene skeleton. In the case that R 2 is not an amino group, Ar 1 and Ar 2independently represent an unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted aromatic hydrocarbon group having 6 to 60 carbon atoms substituted by a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a dibenzofuranyl group or a benzonaphthofuranyl group, or a group represented by the general formula (g2). In the case where the organic compound does not have two or more substituted or unsubstituted amine skeletons, Ar 1 and Ar 2independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms or a group represented by the general formula (g2).

[0170]

[0141] It should be noted that R 11 to R 18 in the general formula (g2) independently represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. One of Z 1 and Z 2is bonded to a nitrogen atom in the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. It should be noted that specific examples of R 11 to R 18 in the group represented by the general formula (g2) are the same as those for R 1 to R 8 in the organic compound represented by the general formula (G1). Furthermore, specific examples of one of Z 1 and Z 2which is not bonded to a nitrogen atom in the group represented by the general formula (g1) are the same as those for one of A and B in the organic compound represented by the general formula (g1) which is not represented by the general formula (g1). That is, one of Z 1 and Z 2 which is not bonded to a nitrogen atom in the group represented by the general formula (g1), represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. It should be noted that specific examples thereof are the same as those for the above substituents R1 to R 8 are.

[0142] Specific skeleton examples of the aromatic hydrocarbon group with 6 to 60 carbon atoms, known as Ar 1 and Ar 2 The substituents that can be used in the general formula (g1) are the skeletons represented by the structural formulas (2-1) to (2-13). Note that there is no restriction on the site of substitution, and each group can consist of a variety of skeletons.

[0143] It should be noted that in the case where Ar 1 and Ar 2in the general formula (g1) are each an aromatic hydrocarbon group comprising a substituent, the substituent may be a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a dibenzofuranyl group or a benzonaphthofuranyl group. In the case where Ar 1 and Ar 2are each an aromatic hydrocarbon group comprising a substituent, and the substituent is a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen or a haloalkyl group having 1 to 6 carbon atoms, are specific structural examples of Ar 1 and Ar 2 the same as those represented by formulas (1-1) to (1-40) used above as specific examples of R 1 to R 8 have been shown in the general formula (G1).

[0144] In the case where Ar 1 and Ar 2in the general formula (g1) are each an aromatic hydrocarbon group comprising a substituent, and the substituent is a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a dibenzofuranyl group or a benzonaphthofuranyl group, specific examples of Ar 1 and Ar 2 represented by formulas (1-41) to (1-117). For all substituents represented by formulas (1-41) to (1-117), there is no restriction on the site of substitution.

[0145] Specific examples of the substituents represented by formula (g2) are as follows.

[0146] Another embodiment of the present invention is the organic compound in which the group represented by the general formula (g1) is a group represented by the general formula (g3).

[0147] It should be noted that Ar 3 and Ar 4 in the general formula (g3) independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted benzonaphthofuranyl group, or a substituted or unsubstituted dinaphthofuranyl group. Ar 3 and Ar 4 are the same as Ar 1 and Ar 2 in the general formula (g1). It should be noted that the sum of the carbon atoms of Ar 3 and Ar 5 is less than or equal to 60 and the sum of the carbon atoms of Ar 4 and Ar 6is less than or equal to 60.

[0148] Ar 5 and Ar 6 independently represent a substituted or unsubstituted divalent aromatic hydrocarbon group having 6 to 54 carbon atoms, and n and m independently represent 0 to 2. It should be noted that the sum of the carbon atoms of Ar 3 and Ar 5 less than or equal to 60 and the sum of the carbon atoms of Ar 4 and Ar 6 is less than or equal to 60. Specific examples of Ar 5 and Ar 6 are divalent groups with skeletons represented by the structural formulas (2-1) to (2-13).

[0149] In the organic compound with the above structure, Ar 3 and Ar 4each represent a substituted or unsubstituted phenyl group, a substituted or unsubstituted naphthyl group, a substituted or unsubstituted anthracenyl group, or a substituted or unsubstituted pyrenyl group, which enables the transport layer to exhibit high heat resistance, good film quality, and favorable hole transport properties. In particular, Ar 3 and Ar 4 each preferably represents a phenyl group, since the layer can be deposited efficiently with favorable hole transport properties.

[0150] In the organic compound with the above structure, Ar 5 and Ar 6each represent a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthylene group, a substituted or unsubstituted anthracenylene group, or a substituted or unsubstituted pyrenylene group, which enables the transport layer to exhibit high heat resistance, good film quality, and favorable hole transport properties. In particular, Ar 5 and Ar 6 each preferably represents a phenylene group, since the layer can be deposited efficiently with favorable hole transport properties.

[0151] In the organic compound having the above structure, it is particularly preferable that one of n and m is 1 and the other is 0, in which case a high-quality film having favorable hole transport properties is obtained.

[0152] Specific examples of the organic compound having the above structure are shown below.

[0153] The above organic compounds can be synthesized by the synthesis schemes (a-1), (a-2), (b-1) and (b-2) shown below.

[0154] A synthesis method of the organic compound represented by the general formula (G1) is described. R 1 to R 8in the general formula (G1), independently of one another, represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. One of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms.

[0155] It should be noted that Ar 1 and Ar 2 in the general formula (g1) independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. In the case where Ar 1 and Ar 2 each comprise a substituent, the substituent comprises a benzonaphthofuranyl group and a dinaphthofuranyl group.

[0156] Thus, general formula (G1) can be represented by general formula (G1-a) or (G1-b). Various reactions can be used in the synthesis method of the organic compounds represented by general formulas (G1-a) and (G1-b). Note that the synthesis method of the organic compounds represented by general formulas (G1-a) and (G1-b) of one embodiment of the present invention is not limited to the following synthesis method. <Syntheseverfahren der durch die allgemeine Formel (G1-a) dargestellten organischen Verbindung>

[0157] The organic compound of one embodiment of the present invention represented by the general formula (G1-a) can be synthesized by the synthesis scheme (a-1) or (a-2) shown below.

[0158] That is, a benzonaphthofuran compound (Compound 1) is coupled with diarylamine (Compound 2), thereby yielding a benzonaphthofuranylamino compound (G1-a). Alternatively, a benzonaphthofuranylamine compound (Compound 3) is coupled with a compound having an aryl skeleton (Compound 4), thereby yielding a benzonaphthofuranylamino compound (G1-a). Synthesis Schemes (a-1) and (a-2) are shown below.

[0159] R 1 to R 8in the synthesis schemes (a-1) and (a-2) independently represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. A represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. Ar 1 and Ar 2independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. In the case where Ar 1 and Ar 2 each comprise a substituent, the substituent comprises a benzonaphthofuranyl group and a dinaphthofuranyl group, but no amino group.

[0160] X 1 and X 4 independently represent chlorine, bromine, iodine or a triflate group, and X 2 and X 3 independently represent hydrogen, an organotin group or the like.

[0161] In the case where the Buchwald-Hartwig reaction using a palladium catalyst is used in the synthesis schemes (a-1) and (a-2), a palladium compound such as bis(dibenzylideneacetone)palladium(0), palladium(II) acetate, [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride, tetrakis(triphenylphosphine)palladium(0) or allylpalladium(II) chloride (dimer) and a ligand such as phenyl palladium(II) chloride can be used. B. Tri(tert-butyl)phosphine, tri(n-hexyl)phosphine, tricyclohexylphosphine, di(1-adamantyl)-n-butylphosphine, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, tri(ortho-tolyl)phosphine, or (S)-6,6'-dimethoxybiphenyl-2,2'-diyl)bis(diisopropylphosphine) (abbreviation: cBRIDP (registered trademark)) can be used. An organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, cesium carbonate, or sodium carbonate, or the like, can be used in the reaction.Toluene, xylene, benzene, tetrahydrofuran, dioxane, or the like can be used as solvents in the reaction. The reagents that can be used in the reaction are not limited to the above reagents.

[0162] In the case where in the synthesis schemes (a-1), (a-2) and (b-1) the Ullmann reaction is carried out using copper or a copper compound, X 1 and X 4 independently represent chlorine, bromine or iodine and represent X 2 and X 3Hydrogen represents hydrogen. Copper or a copper compound can be used for the reaction. Examples of the base used include an inorganic base such as potassium carbonate. Examples of the solvent used for the reaction include 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (DMPU), toluene, xylene, and benzene. In the Ullmann reaction, the target product can be obtained in a shorter time and in a higher yield when the reaction temperature is 100°C or higher; therefore, DMPU or xylene, which have a high boiling point, is preferably used. A reaction temperature of 150°C or higher is further preferred, and accordingly, DMPU is more preferably used. The reagents used for the reaction are not limited to the above reagents. <Syntheseverfahren der durch die allgemeine Formel (G1-b) dargestellten organischen Verbindung>

[0163] The organic compound of the present invention represented by the general formula (G1-b) can be synthesized by the synthesis scheme (b-1) or (b-2) shown below.

[0164] That is, a benzonaphthofuran compound (compound 5) is coupled with diarylamine (compound 6), thereby yielding a benzonaphthofuranylamino compound (G1-b). Alternatively, benzonaphthofuranylamine (compound 7) is coupled with a compound having an aryl skeleton (compound 8), thereby yielding a benzonaphthofuranylamino compound (G1-b). Synthesis Schemes (b-1) and (b-2) are shown below.

[0165] R 1 to R 8in the synthesis schemes (b-1) and (b-2) independently represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. A represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. Ar 1 and Ar 2independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. In the case where Ar 1 and Ar 2 each comprise a substituent, the substituent comprises a benzonaphthofuranyl group and a dinaphthofuranyl group, but no amino group.

[0166] X 1 and X 4 independently represent chlorine, bromine, iodine or a triflate group, and X 2 and X 3 independently represent hydrogen, an organotin group or the like.

[0167] In the case where the Buchwald-Hartwig reaction using a palladium catalyst is used in the synthesis schemes (b-1) and (b-2), a palladium compound such as bis(dibenzylideneacetone)palladium(0), palladium(II) acetate, [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride, tetrakis(triphenylphosphine)palladium(0) or allylpalladium(II) chloride (dimer) and a ligand such as phenyl palladium(II) chloride can be used. B. Tri(tert-butyl)phosphine, tri(n-hexyl)phosphine, tricyclohexylphosphine, di(1-adamantyl)-n-butylphosphine, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, tri(ortho-tolyl)phosphine, or (S)-6,6'-dimethoxybiphenyl-2,2'-diyl)bis(diisopropylphosphine) (abbreviation: cBRIDP (registered trademark)) can be used. An organic base such as sodium tert-butoxide, an inorganic base such as potassium carbonate, cesium carbonate, or sodium carbonate, or the like, can be used in the reaction.Toluene, xylene, benzene, tetrahydrofuran, dioxane, or the like can be used as solvents in the reaction. The reagents that can be used in the reaction are not limited to the above reagents.

[0168] In the case where in the synthesis schemes (b-1) and (b-2) the Ullmann reaction is carried out using copper or a copper compound, X 1 and X 4 independently represent chlorine, bromine or iodine and represent X 2 and X 3Hydrogen represents hydrogen. Copper or a copper compound can be used for the reaction. Examples of the base used include an inorganic base such as potassium carbonate. Examples of the solvent used for the reaction include 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)pyrimidinone (DMPU), toluene, xylene, and benzene. In the Ullmann reaction, the target product can be obtained in a shorter time and in a higher yield when the reaction temperature is 100°C or higher; therefore, DMPU or xylene, which have a high boiling point, is preferably used. A reaction temperature of 150°C or higher is further preferred, and accordingly, DMPU is more preferably used. The reagents used for the reaction are not limited to the above reagents. (Embodiment 3)

[0169] In this embodiment, a light-emitting device including the light-emitting element described in Embodiment 1 will be described.

[0170] In this embodiment, the light-emitting device manufactured using the light-emitting element described in Embodiment 1 is described by Fig. 2A and Fig. 2B. It should be noted that Fig. 2A is a plan view of the light emitting device and Fig. 2B is a cross-sectional view along lines AB and CD of the Fig. 2A. This light-emitting device includes a driving circuit section (a source line driving circuit) 601, a pixel section 602, and a driving circuit section (a gate line driving circuit) 603, which control the light emission of a light-emitting element and are shown with dashed lines. Reference numeral 604 denotes a sealing substrate; 605, a sealing material; and 607, a space surrounded by the sealing material 605.

[0171] Reference numeral 608 denotes a line for transmitting signals to be input to the source line driver circuit 601 and the gate line driver circuit 603, and for receiving signals such as a video signal, a clock signal, a start signal, and a reset signal from a flexible printed circuit (FPC) 609 serving as an external input terminal. Although only the FPC is illustrated here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes, within its category, not only the light-emitting device itself but also the light-emitting device provided with the FPC or the PWB.

[0172] Next, a cross-sectional structure is created based on Fig. 2B. The driver circuit portions and the pixel portion are formed over an element substrate 610; Fig. 2B shows the source line driver circuit 601, which is a driver circuit portion, and a pixel of the pixel portion 602.

[0173] The element substrate 610 may be a substrate comprising glass, quartz, an organic resin, a metal, an alloy, or a semiconductor, or a plastic substrate formed from a fiber reinforced plastic (FRP), poly(vinyl fluoride) (PVF), polyester, or acrylic.

[0174] The structure of the transistors used in the pixels and driver circuits is not particularly limited. For example, inverted-staggered transistors or staggered transistors can be used. Furthermore, top-gate transistors or bottom-gate transistors can be used. A semiconductor material used for the transistors is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, or the like can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, can also be used.

[0175] There is no particular restriction on the crystallinity of a semiconductor material used for transistors, and an amorphous semiconductor or a semiconductor with crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single-crystal semiconductor, or a semiconductor partially containing crystal regions) can be used. Preferably, a semiconductor with crystallinity is used, in which case, deterioration of transistor characteristics can be suppressed.

[0176] Here, an oxide semiconductor is preferably used for semiconductor devices such as the transistors provided in pixels and driver circuits, and the transistors used for touch sensors described later, and the like. Specifically, an oxide semiconductor having a larger band gap than silicon is preferably used. By using an oxide semiconductor having a larger band gap than silicon, the off-state current of the transistors can be reduced.

[0177] The oxide semiconductor preferably contains at least one of indium (In) and zinc (Zn). The oxide semiconductor more preferably contains an oxide represented by an In-M-Zn-based oxide (M represents a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0178] In particular, as the semiconductor layer, it is preferable to use an oxide semiconductor film which includes a plurality of crystal parts whose c-axes are oriented perpendicular to a surface on which the semiconductor layer is formed or the top surface of the semiconductor layer, and in which the adjacent crystal parts have no grain boundary.

[0179] The use of such materials for the semiconductor layer makes it possible to provide a highly reliable transistor in which changes in electrical properties are suppressed.

[0180] Thanks to the transistor's low off-state current, a charge accumulated in a capacitor via a transistor comprising the semiconductor layer described above can be retained for a long time. When such a transistor is used in a pixel, the operation of a driver circuit can be interrupted while maintaining a grayscale of an image displayed in each display area. As a result, an electronic device with very low power consumption can be obtained.

[0181] To stabilize the characteristics of the transistor, a base film is preferably provided. The base film can be formed to have a single-layer structure or a multi-layer structure using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The base film can be formed by a sputtering method, a chemical vapor deposition (CVD) method (e.g., a plasma CVD method, a thermal CVD method, or a metal organic CVD (MOCVD) method), an atomic layer deposition (ALD) method, a coating method, a printing method, or the like. Note that the base film is not necessarily provided.

[0182] Note that an FET 623 is illustrated as a transistor formed in the driver circuit section 601. Furthermore, the driver circuit may be formed using any of various circuits, such as a CMOS circuit, a PMOS circuit, or an NMOS circuit. Although a driver-integrated type in which the driver circuit is formed over the substrate is described in this embodiment, the driver circuit is not necessarily formed over the substrate, and the driver circuit may be formed outside the substrate rather than over the substrate.

[0183] Pixel section 602 includes a plurality of pixels including a switching FET 611, a current-controlling FET 612, and an anode 613 electrically connected to a drain of current-controlling FET 612. An embodiment of the present invention is not limited to this structure. Pixel section 602 may include three or more FETs and a capacitor in combination.

[0184] It should be noted that here, in order to cover an end portion of the anode 613, an insulator 614 is formed using a positive photosensitive acrylic resin film.

[0185] To improve coverage with an EL layer or the like to be formed later, the insulator 614 is formed to have a curved surface with a curvature at its upper or lower end portion. For example, in the case where a positive photosensitive acrylic is used for a material of the insulator 614, preferably only the upper end portion of the insulator 614 has a curved surface with a radius of curvature (0.2 μm to 3 μm). Either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0186] An EL layer 616 and a cathode 617 are formed over the anode 613. Here, a material having a high work function is preferably used as the material used for the anode 613. For example, a single-layer film of an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 wt% to 20 wt% zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, or the like; a stacked film of a titanium nitride film and a film containing aluminum as its main component; a stacked film of three layers of a titanium nitride film, a film containing aluminum as its main component, and a titanium nitride film; or the like can be used. The multilayer structure enables low conduction resistance and good ohmic contact.

[0187] The EL layer 616 is formed by one of various methods, such as an evaporation method using an evaporation mask, an inkjet method, and a spin coating method. The EL layer 616 has the structure described in Embodiment 1. As another material included in the EL layer 616, a low-molecular compound or a high-molecular compound (including an oligomer or a dendrimer) can be used.

[0188] As the material used for the cathode 617 formed over the EL layer 616, a material with a low work function (e.g., Al, Mg, Li, Ca, or an alloy or compound thereof, such as MgAg, Mgln, or AlLi) is preferably used. In the case where light generated in the EL layer 616 is transmitted through the cathode 617, a stacked arrangement of a thin metal film and a transparent conductive film (e.g., ITO, indium oxide containing 2 wt% to 20 wt% zinc oxide, indium tin oxide containing silicon, or zinc oxide (ZnO)) is preferably used for the cathode 617.

[0189] Note that the light-emitting element is formed with the anode 613, the EL layer 616, and the cathode 617. The light-emitting element is the light-emitting element described in Embodiment 1. In the light-emitting device of this embodiment, the pixel section including a plurality of light-emitting elements may include both the light-emitting element described in Embodiment 1 and a light-emitting element having a different structure.

[0190] The sealing substrate 604 is attached to the element substrate 610 with the sealing material 605 such that the light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The space 607 may be filled with a filler, or may be filled with an inert gas (such as nitrogen or argon) or the sealing material. It is preferable that the sealing substrate be provided with a recessed portion and a desiccant be provided in the recessed portion, in which case deterioration due to the influence of moisture can be suppressed.

[0191] An epoxy-based resin or a glass frit is preferably used for the sealing material 605. Such a material should preferably allow as little moisture or oxygen permeation as possible. A glass substrate, a quartz substrate, or a plastic substrate made of fiber-reinforced plastic (FRP), poly(vinyl fluoride) (PVF), polyester, or acrylic can be used as the sealing substrate 604.

[0192] Although in Fig. 2A and Fig. 2B, a protective film may be provided over the cathode. An organic resin film or an inorganic insulating film may be formed as the protective film. The protective film may be formed to cover an exposed portion of the sealing material 605. The protective film may be provided to cover surfaces and side surfaces of the pair of substrates and exposed side surfaces of a sealing layer, an insulating layer, and the like.

[0193] The protective film can be formed using a material that does not easily transmit contaminants such as water. Thus, the diffusion of contaminants such as water from the outside to the inside can be effectively prevented.

[0194] As the material for the protective film, an oxide, a nitride, a fluoride, a sulfide, a ternary compound, a metal, a polymer or the like can be used. For example, the material may include alumina, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, gallium nitride, a nitride containing titanium and aluminum, an oxide containing titanium and aluminum, an oxide containing aluminum and zinc, a sulfide containing manganese and zinc, a sulfide containing cerium and strontium, an oxide containing erbium and aluminum, an oxide containing yttrium and zirconium, or the like.

[0195] The protective film is preferably formed using a deposition method with favorable step coverage. One such method is an atomic layer deposition (ALD) method. A material that can be deposited by an ALD method is preferably used for the protective film. A dense protective film with reduced defects, such as cracks or pinholes, or with a uniform thickness can be formed by an ALD method. Furthermore, damage caused by a process element during formation of the protective film can be reduced.

[0196] Using an ALD process, a uniform protective film with few defects can be formed, for example, even on a surface with a complex irregular shape or on the top, side, and bottom surfaces of a touchscreen.

[0197] The light-emitting device manufactured by using the light-emitting element described in Embodiment 1 can be obtained as described above.

[0198] The light-emitting device of this embodiment is manufactured using the light-emitting element described in Embodiment 1 and can therefore have advantageous characteristics. In particular, since the light-emitting element described in Embodiment 1 has a long lifetime, the light-emitting device can have high reliability. Since the light-emitting device using the light-emitting element described in Embodiment 1 has high emission efficiency, the light-emitting device can achieve low power consumption.

[0199] Fig. 3A and Fig. 3B each illustrates an example of a light-emitting device in which a full-color display is achieved by forming a light-emitting element having white light emission and using color layers (color filters) and the like. Fig. 3A illustrates a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, a pixel portion 1040, a driving circuit portion 1041, anodes 1024W, 1024R, 1024G, and 1024B of light-emitting elements, a partition wall 1025, an EL layer 1028, a cathode 1029 of the light-emitting elements, a sealing substrate 1031, a sealing material 1032, and the like.

[0200] In Fig. 3A, color layers (a red color layer 1034R, a green color layer 1034G, and a blue color layer 1034B) are attached to a transparent base material 1033. A black matrix 1035 may be additionally provided. The transparent base material 1033, which is provided with the color layers and the black matrix, is aligned with and attached to the substrate 1001. Note that the color layers and the black matrix 1035 are covered with a covering layer 1036. In Fig. 3A, the light emitted from one part of the light-emitting layer does not pass through the color layers, while the light emitted from the other part of the light-emitting layer does pass through the color layers. Since the light that does not pass through the color layers is white, and the light that passes through one of the color layers is red, blue, or green, an image can be displayed using pixels of the four colors.

[0201] Fig. 3B illustrates an example in which the color layers (the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B) are provided between the gate insulating film 1003 and the first interlayer insulating film 1020. As in the structure, the color layers may be provided between the substrate 1001 and the sealing substrate 1031.

[0202] The light-emitting device described above is a light-emitting device having a structure in which light is extracted from the side of the substrate 1001 on which the FETs are formed (a bottom-emission structure), but it may be a light-emitting device having a structure in which light is extracted from the side of the sealing substrate 1031 (a top-emission structure). Fig. 4 is a cross-sectional view of a light-emitting device with a top-emission structure. In this case, a substrate that does not transmit light can be used as the substrate 1001. The process up to the step of forming a connection electrode connecting the FET and the anode of the light-emitting element is performed in a similar manner to that of the light-emitting device with a bottom-emission structure. A third interlayer insulating film 1037 is then formed to cover an electrode 1022. This insulating film may have a planarization function. The third interlayer insulating film 1037 may be formed using a material similar to that of the second interlayer insulating film, or alternatively, using another known material.

[0203] The anodes 1024W, 1024R, 1024G and 1024B of the light-emitting elements each serve as anode, but they can also serve as cathode. In the case of a Fig. In the light-emitting device with a top-emission structure shown in Figure 4, the anodes are preferably further reflective electrodes. The EL layer 1028 is formed to have a structure similar to the structure of the EL layer 103 described in Embodiment 1, with which white light emission can be achieved.

[0204] In the case of a top issue structure as in Fig. 4, sealing can be performed using the sealing substrate 1031 on which the color layers (the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B) are provided. The sealing substrate 1031 can be provided with the black matrix 1035 sandwiched between pixels. The color layers (the red color layer 1034R, the green color layer 1034G, and the blue color layer 1034B) and the black matrix can be covered with the covering layer 1036. Note that a light-transmitting substrate is used as the sealing substrate 1031. Although an example is shown here in which a full-color display is performed using four colors, namely red, green, blue, and white, there is no particular limitation, and a full-color display may be performed using four colors, namely red, yellow, green, and blue, or using three colors, namely red, green, and blue.

[0205] A microcavity structure can be advantageously used in the light-emitting device with a top-emission structure. A light-emitting element with a microcavity structure is formed using a reflective electrode as the anode and a semi-transparent and semi-reflective electrode as the cathode. The light-emitting element with a microcavity structure includes at least one EL layer between the reflective electrode and the semi-transparent and semi-reflective electrode, which includes at least one light-emitting layer serving as the light-emitting region.

[0206] It should be noted that the reflective electrode should have a visible light reflectivity of 40% to 100%, preferably 70% to 100% and a resistivity of 1 × 10 -2Ωcm or lower. In addition, the semi-transparent and semi-reflective electrode has a visible light reflectivity of 20% to 80%, preferably 40% to 70%, and a resistivity of 1 × 10 -2 Ωcm or lower.

[0207] Light emitted from the light-emitting layer to the EL layer is reflected by the reflective electrode and the semi-transparent and semi-reflective electrode and resonated.

[0208] In the light-emitting element, the optical path length between the reflective electrode and the semi-transparent and semi-reflective electrode can be changed by changing the thickness of the transparent conductive film, the composite material, the charge-transport material, and the like. In this way, light with a wavelength that resonates between the reflective electrode and the semi-transparent and semi-reflective electrode can be amplified, while light with a wavelength that does not resonate between them can be attenuated.

[0209] It should be noted that light reflected back from the reflective electrode (first reflected light) significantly interferes with the light directly entering the semi-transparent and semi-reflective electrode from the light-emitting layer (first incident light). For this reason, the optical path length between the reflective electrode and the light-emitting layer is preferably set to (2n-1)λ / 4 (n is a natural number of 1 or greater, and λ is a wavelength of the color to be amplified). By adjusting the optical path length, the phases of the first reflected light and the first incident light can be aligned, and light emitted from the light-emitting layer can be further amplified.

[0210] Note that in the above structure, the EL layer may include a plurality of light-emitting layers or a single light-emitting layer. The above-described tandem light-emitting element may be combined with a plurality of EL layers; for example, a light-emitting element may have a structure in which a plurality of EL layers are provided, a charge generation layer is provided between the EL layers, and each EL layer includes a plurality of light-emitting layers or a single light-emitting layer.

[0211] With the microcavity structure, the emission intensity at a specific wavelength can be increased in the forward direction, thereby reducing power consumption. Note that in the case of a light-emitting device that displays images with subpixels of four colors, namely red, yellow, green, and blue, the light-emitting device can exhibit advantageous properties because the luminance can be increased thanks to the yellow light emission, and each subpixel can have a microcavity structure suitable for wavelengths of the corresponding color.

[0212] The light-emitting device of this embodiment is manufactured using the light-emitting element described in Embodiment 1 and can therefore exhibit advantageous characteristics. In particular, since the light-emitting element described in Embodiment 1 has a long lifetime, the light-emitting device can exhibit high reliability. Since the light-emitting device using the light-emitting element described in Embodiment 1 has high emission efficiency, the light-emitting device can achieve low power consumption.

[0213] The active matrix light-emitting device has been described above, whereas a passive matrix light-emitting device will be described below. Fig. 5A and Fig. 5B illustrate a passive matrix light-emitting device fabricated using the present invention. It should be noted that Fig. 5A is a perspective view of the light emitting device and Fig. 5B is a cross-sectional view along the line XY in Fig. 5A is. In Fig. 5A and Fig. 5B, an EL layer 955 is provided between an electrode 952 and an electrode 956 above a substrate 951. An end portion of the electrode 952 is covered with an insulating layer 953. A separating layer 954 is disposed above the insulating layer 953. The sidewalls of the separating layer 954 are tapered so that the distance between both sidewalls gradually decreases toward the surface of the substrate. In other words, a cross-section taken along the short side direction of the separating layer 954 is trapezoidal, and the lower side (a side of the trapezoid that is parallel to the surface of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (a side of the trapezoid that is parallel to the surface of the insulating layer 953 and not in contact with the insulating layer 953).The separation layer 954 thus provided can prevent defects in the light-emitting element due to static electricity or the like. The passive matrix light-emitting device also includes the light-emitting element described in Embodiment 1; thus, the light-emitting device can have high reliability or low power consumption.

[0214] Since many microfine light-emitting elements in a matrix can be separately controlled in the light-emitting device described above, the light-emitting device can be suitably used as a display device for displaying images.

[0215] This embodiment can be freely combined with one of the other embodiments. (Embodiment 4)

[0216] In this embodiment, an example in which the light-emitting element described in Embodiment 1 is used for a lighting device will be described with reference to Fig. 6A and Fig. 6B. Fig. 6B is a plan view of the lighting device, and Fig. 6A is a cross-sectional view taken along the line ef in Fig. 6B.

[0217] In the lighting device of this embodiment, an anode 401 is formed over a substrate 400, which serves as a support and has a light-transmitting property. The anode 401 corresponds to the anode 101 of Embodiment 1. When light is extracted via the anode 401 side, the anode 401 is formed using a material with a light-transmitting property.

[0218] A contact pad 412 for applying a voltage to a cathode 404 is provided above the substrate 400.

[0219] An EL layer 403 is formed over the anode 401. The structure of the EL layer 403 corresponds, for example, to the structure of the EL layer 103 of Embodiment 1 or the structure in which the light-emitting units 511 and 512 and the charge generation layer 513 are combined. Refer to the descriptions regarding the structure.

[0220] The cathode 404 is formed to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 of Embodiment 1. The cathode 404 is formed using a material with a high reflectance when light is extracted from the anode 401 side. The cathode 404 is connected to the pad 412, thereby applying a voltage.

[0221] As described above, the lighting device described in this embodiment includes a light-emitting element including the anode 401, the EL layer 403, and the cathode 404. Since the light-emitting element is a light-emitting element with high emission efficiency, the lighting device of this embodiment can be a low-power lighting device.

[0222] The substrate 400 provided with the light-emitting element having the above structure is fixed to a sealing substrate 407 with the sealing materials 405 and 406, and sealing is performed, thereby completing the lighting device. It is possible to use only the sealing material 405 or the sealing material 406. The inner sealing material 406 (not shown) Fig. 6B) can be mixed with a desiccant, which allows the adsorption of moisture and leads to increased reliability.

[0223] If portions of the contact pad 412 and the anode 401 extend outside the sealing materials 405 and 406, the protruding portions can serve as external input terminals. An IC chip 420 equipped with a converter or the like can be arranged over the external input terminals.

[0224] The lighting device described in this embodiment includes the light-emitting element described in Embodiment 1 as the EL element; thus, the light-emitting device can have high reliability. Furthermore, the light-emitting device can consume less power. (Embodiment 5)

[0225] In this embodiment, examples of electronic devices each including the light-emitting element described in Embodiment 1 are described. The light-emitting element described in Embodiment 1 has a long lifetime and high reliability. As a result, the electronic devices described in this embodiment can each have a light-emitting portion with high reliability.

[0226] Examples of electronic devices to which the above light-emitting element is applied include televisions (also referred to as TVs or television receivers), monitors for computers and the like, cameras such as digital cameras and digital video cameras, digital photo frames, mobile phones (also referred to as cellular phones or portable telephones), portable game consoles, portable information terminals, audio playback devices, large-scale gaming machines such as pinball machines, and the like. Specific examples of these electronic devices are given below.

[0227] Fig. 7A illustrates an example of a television set. In the television set, a display section 7103 is installed in a cabinet 7101. Here, the cabinet 7101 is supported by a stand 7105. Images can be displayed on the display section 7103, and in the display section 7103, the light-emitting elements described in Embodiment 1 are arranged in a matrix.

[0228] The television can be operated using a control switch on the housing 7101 or a separate remote control 7110. The control buttons 7109 of the remote control 7110 can be used to control the channels and volume, and to control the images displayed on the display section 7103. The remote control 7110 can be provided with a display section 7107 to display the data output from the remote control 7110.

[0229] It should be noted that the television is equipped with a receiver, a modem, and the like. Using the receiver, general television broadcasting can be received. Furthermore, if the television is connected to a communications network wirelessly or wired via the modem, one-way (from a transmitter to a receiver) or two-way (between a transmitter and a receiver, or between receivers) information communication can be achieved.

[0230] Fig. Figure 7B1 illustrates a computer including a main body 7201, a housing 7202, a display section 7203, a keyboard 7204, an external connection terminal 7205, a pointing device 7206, and the like. Note that this computer is manufactured by arranging the light-emitting elements described in Embodiment 1 in a matrix in the display section 7203. The computer in Fig. 7B1 can be a Fig. 7B2. The computer in Fig. 7B2 is provided with a second display section 7210 instead of the keyboard 7204 and the pointing device 7206. The second display section 7210 includes a touchscreen, and input can be performed by controlling images displayed on the second display section 7210 with a finger or an associated stylus. The second display section 7210 can also display images other than the input display. The display section 7203 can also include a touchscreen. By connecting the two displays with a hinge, problems can be prevented; for example, the displays can be prevented from cracking or being damaged while storing or carrying the computer.

[0231] Fig. Figure 7C illustrates a portable game console having two housings, a housing 7301 and a housing 7302, which are connected via a hinge part 7303 so that the portable game console can be opened or closed. The housing 7301 includes a display section 7304 in which the light-emitting elements described in Embodiment 1 are arranged in a matrix, and the housing 7302 includes a display section 7305. In addition, the portable game console in Fig. 7C, a speaker section 7306, a recording medium insertion section 7307, an LED lamp 7308, input means (an operation button 7309, a connection terminal 7310, a sensor 7311 (a sensor having a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays) and a microphone 7312), and the like.Of course, the structure of the portable game console is not limited to the above, as long as the display section in which the light-emitting elements described in Embodiment 1 are arranged in a matrix is ​​used as the display section 7304 and / or the display section 7305, and the structure may include other accessories as necessary. The portable game console in . Fig. 7C has a function for reading a program or data stored in a storage medium to display it on the display section, and a function for sharing information with another portable game console via wireless communication. It should be noted that functions of the portable game console in Fig. 7C are not limited to this, and the portable game console can have various functions.

[0232] Fig. 7D illustrates an example of a portable information terminal. A mobile phone 7400 is provided with a display section 7402 installed in a case 7401, operation buttons 7403, an external connection terminal 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone 7400 includes the display section 7402 in which the light-emitting elements described in Embodiment 1 are arranged in a matrix.

[0233] When the display section 7402 of the portable information terminal in Fig. 7D is touched with a finger or the like, data can be input into the portable information terminal. In this case, operations such as making a call and writing an email can be performed by touching the display section 7402 with a finger or the like.

[0234] There are mainly three screen modes of the display section 7402. The first mode is a display mode, which mainly displays images. The second mode is an input mode, which mainly inputs information such as characters. The third mode is a display and input mode, which combines two modes: display mode and input mode.

[0235] For example, when making a call or composing an email, a text input mode is selected for the display section 7402 so that characters displayed on a screen can be input. In this case, it is preferable that a keyboard or a numeric keypad be displayed on almost the entire screen of the display section 7402.

[0236] When a detecting device including a sensor for detecting inclination, such as a gyroscope or an acceleration sensor, is provided within the portable information terminal, a display on the screen of the display section 7402 can be automatically changed in its direction by determining the orientation of the portable information terminal (depending on whether the portable information terminal is placed horizontally or vertically).

[0237] The screen modes are switched by touching the display section 7402 or by operating the control buttons 7403 of the body 7401. The screen modes can be switched depending on the type of images displayed on the display section 7402. For example, if a signal of an image displayed on the display section is a moving image data signal, the screen mode is switched to the display mode. If the signal is a text data signal, the screen mode is switched to the input mode.

[0238] Moreover, in the input mode, when a signal detected by an optical sensor in the display section 7402 is detected and the input by touching the display section 7402 is not performed within a certain period of time, the screen mode can be controlled to switch from the input mode to the display mode.

[0239] The display section 7402 can serve as an image sensor. For example, an image of a palm print, a fingerprint, or the like can be captured by touching the display section 7402 with the palm or finger, thereby performing personal authentication. Furthermore, an image of a finger vein or a palm vein can be captured by providing a backlight or a scanning light source that emits light in the near-infrared range in the display section.

[0240] It should be noted that the structure shown in this embodiment can be appropriately combined with any of the structures of Embodiments 1 to 4.

[0241] As described above, the application range of the light-emitting device using the light-emitting element described in Embodiment 1 is broad, so this light-emitting device can be applied to electronic devices in various fields. By using the light-emitting element described in Embodiment 1, an electronic device with high reliability can be obtained.

[0242] Fig. Figure 8 shows an example of a liquid crystal display device in which the light-emitting element shown in Embodiment 1 is used for a backlight. The liquid crystal display device in Fig. 8 includes a package 901, a liquid crystal layer 902, a backlight unit 903, and a case 904. The liquid crystal layer 902 is connected to a driver IC 905. The light-emitting element described in Embodiment 1 is used for the backlight unit 903, to which a current is supplied via a terminal 906.

[0243] The light-emitting element described in Embodiment 1 is used for the backlight of the liquid crystal display device; therefore, the backlight can have reduced power consumption. In addition, the use of the light-emitting element described in Embodiment 1 enables the manufacture of a planar emission illumination device and further enables the manufacture of a large-area planar emission illumination device; therefore, the backlight can be a large-area backlight, and the liquid crystal display device can also be a large-area device. In addition, the light-emitting device incorporating the light-emitting element described in Embodiment 1 can be thinner than a conventional light-emitting device; accordingly, the display device can also be thinner.

[0244] Fig. Fig. 9 shows an example in which the light-emitting element described in Embodiment 1 is used for a table lamp, which is a lighting device. The table lamp in Fig. 9 includes a housing 2001 and a light source 2002, and the lighting device described in Embodiment 4 can be used for the light source 2002.

[0245] Fig. 10 illustrates an example in which the light-emitting element described in Embodiment 1 is applied to an indoor lighting device 3001. Since the light-emitting element described in Embodiment 1 has high reliability, the lighting device can have high reliability. Furthermore, since the light-emitting element described in Embodiment 1 can have a large area, the light-emitting element can be applied to a large-area lighting device. Furthermore, since the light-emitting element described in Embodiment 1 is thin, the light-emitting element can be applied to a lighting device with a reduced thickness.

[0246] The light-emitting element described in Embodiment 1 can also be used for a car windshield or a car dashboard. Fig. 11 illustrates an embodiment in which the light-emitting element described in Embodiment 1 is applied to a car windshield and a car instrument panel. Display regions 5000 to 5005 each include the light-emitting element described in Embodiment 1.

[0247] The display portion 5000 and the display portion 5001 are display devices provided in the car windshield, incorporating the light-emitting elements described in Embodiment 1. The light-emitting elements described in Embodiment 1 can be formed into a so-called see-through display device through which the opposite side can be seen by including an anode and a cathode composed of electrodes with light transmittance. Such see-through display devices can even be provided in the car windshield without obstructing the view.It should be noted that in the case where a driving transistor or the like is provided, it is preferable to use a transistor having a light transmitting property, such as an organic transistor using an organic semiconductor material or a transistor using an oxide semiconductor.

[0248] The display portion 5002 is a display device provided in a pillar portion in which the light-emitting element described in Embodiment 1 is installed. The display portion 5002 can supplement the view obstructed by the pillar by displaying an image captured by an imaging unit in the body. The display portion 5003 in the instrument panel can similarly supplement the view obstructed by the body by displaying an image captured by an imaging unit outside the body, resulting in the elimination of blind spots and the improvement of safety. Displaying a supplementary image for the area that a driver cannot see allows the driver to easily and conveniently determine safety.

[0249] Display areas 5004 and 5005 can provide various types of information, such as navigation data, a speedometer, a tachometer, a mileage reading, a fuel gauge, a gearshift indicator, and an air conditioning setting. The content or layout of the display can be freely changed by a user as appropriate. Note that such information can also be displayed by display areas 5000 to 5003. Display areas 5000 to 5005 can also be used as lighting devices.

[0250] Fig. 12A and Fig. 12B illustrates an example of a foldable tablet computer. Fig. 12A illustrates the tablet computer unfolded. The tablet computer includes a case 9630, a display section 9631a, a display section 9631b, a display mode switch 9034, a power switch 9035, a power-saving mode switch 9036, a clasp 9033, and an operation switch 9038. Note that in the tablet computer, the display section 9631a and / or the display section 9631b are formed using a light-emitting device including the light-emitting element described in Embodiment 1.

[0251] Part of the display section 9631a may be a touchscreen area 9632a, and data can be input when a displayed operation button 9637 is touched. Although only half of the display section 9631a has a display function and the other half has a touchscreen function, an embodiment of the present invention is not limited to this structure. The entire display section 9631a may have a touchscreen function. For example, a keyboard may be displayed on the entire area of ​​the display section 9631a, so that the display section 9631a is used as a touchscreen, and the display section 9631b may be used as a display screen.

[0252] As with the display section 9631a, a part of the display section 9631b may be a touchscreen area 9632b. When a keyboard display / hide button 9639 on the touchscreen is touched with a finger, a stylus, or the like, the keyboard may be displayed on the display section 9631b.

[0253] A touch input can be performed in the touchscreen area 9632a and the touchscreen area 9632b at the same time.

[0254] For example, the display mode switch 9034 can switch the display between portrait mode, landscape mode, and the like, and between monochrome display and color display. The power saving mode switch 9036 can control the display luminance according to the amount of external light detected by an optical sensor in the tablet computer when using the tablet computer. In addition to the optical sensor, another sensing device, such as a sensor for detecting inclination, such as a gyroscope sensor or an acceleration sensor, can be built into the tablet computer.

[0255] Although Fig. While FIG. 12A illustrates an example in which the display section 9631a and the display section 9631b have the same display area, an embodiment of the present invention is not limited to this example. The display section 9631a and the display section 9631b may have different display areas and different display qualities. For example, higher-resolution images may be displayed on one of the display sections 9631a and 9631b.

[0256] Fig. Figure 12B illustrates the tablet computer folded. The tablet computer of this embodiment includes the case 9630, a solar cell 9633, a charge and discharge control circuit 9634, a battery 9635, and a DC-DC converter 9636. Fig. 12B shows a structure including the battery 9635 and the DC-DC converter 9636 as an example of the charge and discharge control circuit 9634.

[0257] Since the tablet computer is foldable, the case 9630 can be closed when the tablet computer is not in use. As a result, the display section 9631a and the display section 9631b can be protected, thereby providing a tablet computer with high durability and high reliability for long-term use.

[0258] The tablet computer in Fig. 12A and Fig. 12B may have other functions such as a function of displaying various types of data (e.g., a still image, a moving image, and a text image), a function of displaying a calendar, a date, a time, or the like on the display portion, a touch input function of operating or editing the data displayed on the display portion by touch input, and a function of controlling processing by various types of software (programs).

[0259] The solar cell 9633, provided on one surface of the tablet computer, can supply power to the touchscreen, the display section, a video signal processing section, or the like. Note that a structure in which the solar cell 9633 is disposed on one or both surfaces of the case 9630 is preferable because the battery 9635 can be charged efficiently.

[0260] The structure and operation of the charge and discharge control circuit 9634 shown in Fig. 12B, are described with reference to a block diagram in Fig. 12C described. Fig. 12C illustrates the solar cell 9633, the battery 9635, the DC-DC converter 9636, a converter 9638, switches SW1 to SW3, and a display section 9631. The battery 9635, the DC-DC converter 9636, the converter 9638, and the switches SW1 to SW3 correspond to the charge and discharge control circuit 9634 in Fig. 12B.

[0261] First, an example of operation in the case where power is generated by the solar cell 9633 using external light will be described. The voltage of the power generated by the solar cell is increased or decreased by the DC-DC converter 9636 to obtain a voltage for charging the battery 9635. Then, when the power of the solar cell 9633 is used to operate the display section 9631, the switch SW1 is turned on, and the voltage of the power is increased or decreased by the converter 9638 to become a voltage required by the display section 9631. When no images are displayed on the display section 9631, the switch SW1 is turned off, and the switch SW2 is turned on to charge the battery 9635.

[0262] Although the solar cell 9633 is described as an example of a power generation means, there is no particular limitation on the power generation means, and the battery 9635 can be charged by another power generation means, such as a piezoelectric element or a thermoelectric conversion element (Peltier element). The battery 9635 can be charged by a non-contact power transmission module that can perform charging by wirelessly (contactlessly) transmitting and receiving power, or one of the other charging means can be used in combination therewith, and the power generation means is not necessarily provided.

[0263] An embodiment of the present invention is not limited to the tablet computer with the Fig. 12A to Fig. 12C as long as the display section 9631 is included.

[0264] Fig. 13A to Fig. 13C illustrate a foldable portable information terminal 9310. Fig. 13A illustrates the portable information terminal 9310 being opened. Fig. 13B illustrates the portable information terminal 9310 during opening or folding. Fig. Figure 13C illustrates the portable information terminal 9310 folded. The portable information terminal 9310 is very easy to carry when folded. When the portable information terminal 9310 is unfolded, a seamless, large display area is highly searchable.

[0265] A display screen 9311 is supported by three housings 9315 connected to each other by hinges 9313. The display screen 9311 may be a touchscreen (an input / output device) incorporating a touch sensor (an input device). The portable information terminal 9310 can be reversibly changed in shape from an unfolded state to a folded state by bending the display screen 9311 using the hinges 9313 at a junction between two housings 9315. The light-emitting device of one embodiment of the present invention can be used for the display screen 9311. A display area 9312 in the display screen 9311 includes a display area positioned on a side surface of the folded portable information terminal 9310.On the display area 9312, information icons, frequently used applications, program shortcuts, and the like can be displayed, and confirmation of information and starting of an application can be easily performed.

[0266] It should be noted that an organic compound having a substituted or unsubstituted benzonaphthofuran skeleton and a substituted or unsubstituted amine skeleton, which is an embodiment of the present invention, can be used for an organic thin-film solar cell. Specifically, the compound has a charge-transporting property and can therefore be used for a charge-transporting layer or a charge-injecting layer. Furthermore, a film composed of a mixture of the compound and an acceptor substance can be used as a charge-generating layer. Furthermore, the compound can be excited by light and can therefore be used for a power-generating layer. [Example 1]<<Synthesebeispiel 1> >

[0267] This synthesis example specifically demonstrates an example for synthesizing N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), which is the organic compound of one embodiment of the present invention, represented by structural formula (142) in the embodiment. The structural formula of BnfABP is as follows. <Schritt 1: Synthese von 6-Jodbenzo[b]naphtho[1,2-d]furan>

[0268] 8.5 g (39 mmol) of benzo[b]naphtho[1,2-d]furan was added to a 500 mL three-necked flask, and the air in the flask was replaced with nitrogen. Then, 195 mL of tetrahydrofuran (THF) was added. After this solution was cooled to -75 °C, 25 mL (40 mmol) of n-butyllithium (a 1.59 mol / L n-hexane solution) was added dropwise to this solution. After the dropwise addition, the resulting solution was stirred at room temperature for 1 hour. After a predetermined period of time, the resulting solution was cooled to -75 °C. Then, a solution in which 10 g (40 mmol) of iodine was dissolved in 40 mL of THF was added dropwise to this solution. After the dropwise addition, the resulting solution was stirred for 17 hours while the temperature of the solution was returned to room temperature. Next, an aqueous sodium thiosulfate solution was added to the mixture, and the resulting mixture was stirred for 1 hour.Subsequently, the organic layer of the mixture was washed with water and dried with magnesium sulfate. After drying, the mixture was gravity filtered to obtain a solution. The obtained solution was suction filtered through Florisil (catalog number 066-05265, manufactured by Wako Pure Chemical Industries, Ltd.) and Celite (catalog number 537-02305, manufactured by Wako Pure Chemical Industries, Ltd.) to obtain a filtrate. The obtained filtrate was concentrated to obtain a solid. The obtained solid was recrystallized from toluene to obtain 6.0 g (18 mmol) of the white powder of the target substance in a yield of 45%. A synthesis scheme (a-1) of step 1 is shown below. <Schritt 2: Synthese von 6-Phenylbenzo[b]naphtho[1,2-d]furan>

[0269] In a 200 mL three-necked flask, 6.0 g (18 mmol) of 6-iodobenzo[b]naphtho[1,2-d]furan, 2.4 g (19 mmol) of phenylboronic acid, 70 mL of toluene, 20 mL of ethanol, and 22 mL of an aqueous potassium carbonate solution (2.0 mol / L) were added. This mixture was degassed by stirring while reducing the pressure. After degassing, the air in the flask was replaced with nitrogen, and then 480 mg (0.42 mmol) of tetrakis(triphenylphosphine)palladium(0) was added to the mixture. The resulting mixture was stirred at 90 °C under a nitrogen stream for 12 hours. After a predetermined period of time, water was added to the mixture, and an aqueous layer was subjected to extraction with toluene. The extracted solution and an organic layer were combined, and the mixture was washed with water and then dried with magnesium sulfate. The mixture was gravity filtered to obtain a filtrate.The obtained filtrate was concentrated to obtain a solid, and the obtained solid was dissolved in toluene. The obtained solution was suction-filtered through Celite (catalog number 531-16855, manufactured by Wako Pure Chemical Industries, Ltd.), Florisil (catalog number 540-00135, manufactured by Wako Pure Chemical Industries, Ltd.), and alumina to obtain a filtrate. The obtained filtrate was concentrated to obtain a solid. The obtained solid was recrystallized from toluene to obtain 4.9 g (17 mmol) of the white solid of the target substance in a yield of 93%. A synthesis scheme (b-1) of step 2 is shown below. <Schritt 3: Synthese von 8-Jod-6-phenylbenzo[b]naphtho[1,2,d]furan>

[0270] 4.9 g (17 mmol) of 6-phenylbenzo[b]naphtho[1,2-d]furan was added to a 300 mL three-necked flask, and the air in the flask was replaced with nitrogen. 87 mL of tetrahydrofuran (THF) was then added. The resulting solution was cooled to -75 °C. Then, 11 mL (18 mmol) of n-butyllithium (a 1.59 mol / L n-hexane solution) was added dropwise to the solution. After the addition, the resulting solution was stirred at room temperature for 1 hour. After a predetermined period of time, the resulting solution was cooled to -75 °C. A solution in which 4.6 g (18 mmol) of iodine was dissolved in 18 mL of THF was added dropwise to the resulting solution. The resulting solution was stirred for 17 hours while the temperature of the solution was returned to room temperature. After stirring, an aqueous sodium thiosulfate solution was added to the mixture, and the resulting mixture was stirred for 1 hour.Subsequently, an organic layer of the mixture was washed with water and dried with magnesium sulfate. The mixture was gravity filtered to obtain a filtrate. The obtained filtrate was suction filtered through Celite (catalog number 531-16855, manufactured by Wako Pure Chemical Industries, Ltd.), Florisil (catalog number 540-00135, manufactured by Wako Pure Chemical Industries, Ltd.), and alumina to obtain a filtrate. The obtained filtrate was concentrated to obtain a solid. The obtained solid was recrystallized from toluene to obtain 3.7 g (8.8 mmol) of the white solid of the target substance in a yield of 53%. A synthesis scheme (c-1) of step 3 is shown below. <Schritt 4: Synthese von 6,N-Diphenylbenzo[b]naphtho[1,2-d]furan-8-amin>

[0271] In a 200 mL three-necked flask, 5.0 g (12 mmol) of 8-iodo-6-phenylbenzo[b]naphtho[1,2-d]furan, synthesized in step 3, and 2.9 g (30 mmol) of sodium tert-butoxide were added. The air in the flask was replaced with nitrogen. Then, 60 mL of toluene, 1.4 g (13 mmol) of aniline, and 0.4 mL of tri(tert-butyl)phosphine (10 wt% hexane solution) were added. After this mixture was degassed under reduced pressure, the temperature was adjusted to 60 °C under a nitrogen stream, 60 mg (0.1 mmol) of bis(dibenzylideneacetone)palladium(0) was added, and this mixture was stirred at 60 °C for 40 minutes. After stirring, the resulting mixture was washed with water and a saturated aqueous sodium chloride solution, and the organic layer was dried with magnesium sulfate. After the magnesium sulfate was removed by gravity filtration, the resulting filtrate was concentrated to obtain a white solid.This solid was purified by silica gel column chromatography (eluent was a mixed solvent of toluene:hexane = 1:2) to obtain 3.5 g of the white solid of the target compound in a yield of 77%. A synthesis scheme (d-1) of step 4 is shown below.

[0272] Below are 1 H-NMR data of the obtained white solid are shown. 1 H-NMR (chloroform-d, 500 MHz): δ = 6.23 (s, 1H), 7.04 (t, J = 7.5 Hz, 1H), 7.24-7.26 (m, 2H), 7.34-7.41 (m, 4H), 7.47 (t, J = 8.0 Hz, 1H), 7.54-7.60 (m, 3H), 7.74 (t, J = 7.5 Hz, 1H), 7.95 (d, J = 6.5 Hz, 2H), 7.99 (dd, J1 = 1.5 Hz, J2 = 7.0 Hz, 1H), 8.03 (s, 1H), 8.08 (d, J = 8.0 Hz, 1H), 8.66 (d, J = 9.0 Hz, 1H) <Schritt 5: Synthese von N-4-Biphenyl-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amin>

[0273] To a 200 mL three-necked flask, 1.3 g (5.0 mmol) of 4-bromobiphenyl, 1.9 g (5.0 mmol) of 6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine, synthesized in step 4, 0.14 g (0.30 mmol) of 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (abbreviation: X-Phos), and 1.5 g (15 mmol) of sodium tert-butoxide were added. The air in the flask was replaced with nitrogen, and then 25 mL of toluene was added. After this mixture was degassed under reduced pressure, the temperature was adjusted to 60 °C under a nitrogen stream, 61 mg (0.10 mmol) of bis(dibenzylideneacetone)palladium(0) was added, and this mixture was stirred at 80 °C for 3 hours. After stirring, the resulting mixture was washed with water and a saturated aqueous sodium chloride solution, and the organic layer was dried with magnesium sulfate.After the magnesium sulfate was removed by gravity filtration, the resulting filtrate was concentrated to obtain a brown solid. This solid was purified by silica gel column chromatography (eluent was a mixed solvent of toluene:hexane = 3:7) to obtain 2.0 g of a light yellow solid of the target substance in a yield of 67%. A synthesis scheme (e-1) of step 5 is shown below.

[0274] Below are 1 H-NMR data of the obtained light yellow solid are shown. Fig. 14A and Fig. 14B are 1 H-NMR diagrams. It should be noted that Fig. 14B is a diagram showing an enlarged portion of Fig. 14A in the range of 7.00 ppm to 9.00 ppm. These results indicate that BnfABP, which is the organic compound of one embodiment of the present invention, was obtained.

[0275] 1 H-NMR (dichloromethane-d2, 500 MHz): δ = 7.11 (t, J = 7.0 Hz, 1H), 7.16 (t, J = 7.0 Hz, 4H), 7.22-7.33 (m, 7H), 7.39-7.47 (m, 5H), 7.53-7.60 (m, 5H), 7.74 (t, J = 7.0 Hz, 1H), 8.02 (s, 1H), 8.06 (d, J = 8.0 Hz, 1H), 8.23 ​​(d, J = 8.0 Hz, 1H), 8.66 (d, J = 8.0 Hz, 1H)

[0276] 1.5 g of the resulting light yellow solid was purified by sublimation. The sublimation purification was carried out for 16 hours at a temperature of 235 °C to 250 °C under a pressure of 3.6 Pa with an argon gas flow rate of 15 ml / min. After sublimation purification, 1.4 g of the light yellow solid of the target substance was obtained with a collection rate of 90%.

[0277] Next, the UV-VIS absorption spectrum (hereinafter referred to simply as "absorption spectrum") and emission spectrum of a toluene solution and a solid thin film of BnfABP were measured. The solid thin film was formed over a quartz substrate by a vacuum evaporation method. The absorption spectrum of the toluene solution was measured with a UV-VIS spectrophotometer (V550, manufactured by JASCO Corporation), and the spectrum of only toluene in a quartz cell was subtracted from the measured spectrum. The absorption spectrum of the thin film was measured with a spectrophotometer (U-4100 spectrophotometer, manufactured by Hitachi High-Technologies Corporation). The emission spectra were measured with a fluorescence spectrophotometer (FS920, manufactured by Hamamatsu Photonics KK). Fig. 15 shows the measurement results of the absorption and emission spectra of the obtained toluene solution and Fig. Figure 16 shows the measurement results of the absorption and emission spectra of the obtained thin film.

[0278] From Fig. 15, the toluene solution of BnfABP exhibits absorption peaks at approximately 376 nm, 340 nm and 321 nm and an emission peak at 417 nm (excitation wavelength: 370 nm).

[0279] From Fig. 16, the thin film of BnfABP exhibits absorption peaks at approximately 387 nm, 346 nm, 326 nm, 294 nm and 262 nm and an emission peak at 440 nm (excitation wavelength: 360 nm).

[0280] The HOMO and LUMO levels of BnfABP were determined by cyclic voltammetry (CV) measurements. A calculation method is described below.

[0281] An electrochemical analyzer (ALS Model 600A or 600C, manufactured by BAS Inc.) was used as the measurement device. Regarding a solution used in the CV measurement, anhydrous dimethylformamide (DMF, product of Sigma-Aldrich Inc., 99.8%, catalog number 22705-6) was used as the solvent, and tetra-n-butylammonium perchlorate (n-Bu4NClO4, product of Tokyo Chemical Industry Co., Ltd., catalog number T0836), which served as a supporting electrolyte, was dissolved in the solvent such that the concentration of tetra-n-butylammonium perchlorate was 100 mmol / L. Furthermore, the object to be measured was also dissolved in the solvent so that its concentration was 2 mmol / L. A platinum electrode (PTE platinum electrode, manufactured by BAS Inc.) was used as the working electrode, another platinum electrode (Pt counter electrode for VC-3 (5 cm), manufactured by BAS Inc.) was used as the auxiliary electrode, and an Ag / Ag +An electrode (RE7 reference electrode for a non-aqueous solvent, manufactured by BAS Inc.) was used as the reference electrode. Note that the measurement was performed at room temperature (20°C to 25°C). In addition, the scanning speed in the CV measurement was set to 0.1 V / s, and an oxidation potential Ea [V] and a reduction potential Ec [V] were measured with respect to the reference electrode. The potential Ea is an intermediate potential of an oxidation-reduction wave, and Ec is an intermediate potential of a reduction-oxidation wave. It was found that the potential energy of the reference electrode used in this example was -4.94 [eV] with respect to the vacuum level, and therefore the HOMO level and the LUMO level can be obtained by the following formula: HOMO level [eV] = -4.94 - Ea and LUMO level [eV] = -4.94 - Ec.Furthermore, the CV measurement was repeated 100 times, and the oxidation-reduction wave at the hundredth cycle and the oxidation-reduction wave at the first cycle were compared to investigate the electrical stability of the compound.

[0282] As a result, the HOMO level of BnfABP was found to be -5.59 eV and the LUMO level was -2.53 eV. The peak intensity of the oxidation-reduction wave after the 100th cycle was 83% of that of the oxidation-reduction wave in the first cycle, indicating that BnfABP is extremely resistant to oxidation. Thermogravimetric differential thermal analysis (TG-DTA) was performed on BnfABP. The measurement was performed using a high vacuum differential thermal balance (TG-DTA2410SA, manufactured by Bruker AXS KK). The measurement was carried out under atmospheric pressure at a temperature increase rate of 10 °C / min under a nitrogen stream (flow rate: 200 ml / min).From the relationship between weight and temperature (thermogravimetry), it was determined that the temperature for 5% weight loss of BnfABP was approximately 370°C. This indicates that BnfABP has high thermal stability. Furthermore, differential scanning calorimetry (DSC) measurement was performed using Pyris1DSC, manufactured by PerkinElmer Inc. In the DSC, after raising the temperature from -10°C to 300°C at a temperature elevation rate of 40°C / min, the temperature was maintained for one minute and then cooled to -10°C at a temperature reduction rate of 40°C / min. This process was repeated twice consecutively. It was determined from the DSC measurement that the glass transition temperature of BnfABP was 97°C, thus demonstrating high thermal stability. [Example 2]<<Synthesebeispiel 2> >

[0283] This synthesis example demonstrates an example for synthesizing N,N-bis(biphenyl-4-yl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), which is the organic compound of one embodiment of the present invention, represented by the structural formula (142) in the embodiment. The structural formula of BBABnf is as follows. <Schritt 1: Synthese von 6-Jodbenzo[b]naphtho[1,2-d]furan>

[0284] This synthesis step is similar to step 1 in Synthesis Example 1. <Schritt 2: Synthese von 6-Phenylbenzo[b]naphtho[1,2-d]furan>

[0285] This synthesis step is similar to step 2 in Synthesis Example 1. <Schritt 3: Synthese von 8-Jod-6-phenylbenzo[b]naphtho[1,2,d]furan>

[0286] This synthesis step is similar to step 3 in Synthesis Example 1. <Schritt 4: Synthese von (9,9-Dimethyl-9H-fluoren-2,7-diyl)bis(6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amin>

[0287] In a 200 ml three-necked flask, 2.1 g (5.0 mmol) of 8-iodo-6-phenylbenzo[b]naphtho[1,2,-d]furan obtained in step 3 of Example 1, 1.6 g (5.0 mmol) of di(1,1'-biphenyl-4-yl)amine, 0.17 g (0.40 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxy-1,1'-biphenyl (abbreviation: S-Phos), and 0.97 g (10 mmol) of sodium tert-butoxide were added. The air in the flask was replaced with nitrogen, and then 25 ml of xylene was added. After this mixture was degassed under reduced pressure, the temperature was adjusted to 80 °C under a nitrogen stream, 0.12 g (0.20 mmol) of bis(dibenzylideneacetone)palladium(0) was added, and this mixture was stirred at 80 °C for 5.5 hours and further stirred at 100 °C for 5 hours. After stirring, the resulting mixture was washed with water and a saturated aqueous sodium chloride solution, and the organic layer was dried with magnesium sulfate.After the magnesium sulfate was removed by gravity filtration, the resulting filtrate was concentrated to obtain a brown solid. The resulting solid was dissolved in toluene and filtered through Celite (catalog number 537-02305, manufactured by Wako Pure Chemical Industries, Ltd.) and alumina. The resulting filtrate was concentrated to obtain 2.0 g of the yellow solid of the target substance in a yield of 67%. A synthesis scheme (d-2) of step 4 is shown below.

[0288] Below are 1 H-NMR data of the obtained yellow solid are shown. Fig. 17A and Fig. 17B are 1 H-NMR diagrams. It should be noted that Fig. 17B is a diagram showing an enlarged part of Fig. 17A in the range of 7.00 ppm to 9.00 ppm. These results indicate that BBABnf, which is the organic compound of one embodiment of the present invention, was obtained.

[0289] 1 H-NMR (dichloromethane-d2, 500 MHz): δ = 7.14-7.19 (m, 3H), 7.22 (d, J = 8.5 Hz, 4H), 7.29-7.33 (m, 3H), 7.41 (t, J = 8.0 Hz, 4H), 7.44-7.49 (m, 3H), 7.55-7.58 (m, 5H), 7.61 (d, J = 8.0 Hz, 4H), 7.74 (t, J = 8.0 Hz, 1H), 8.02 (s, 1H), 8.06 (d, J = 8.0 Hz, 1H), 8.26 (d, 1H), 8.67 (d, J = 8.0 Hz, 1H)

[0290] 2.0 g of the resulting yellow solid was purified by sublimation. The sublimation purification was carried out for 16 hours at a temperature of 270 °C under a pressure of 3.8 Pa with an argon gas flow rate of 15 ml / min. After sublimation purification, 1.7 g of the yellow solid of the target substance was obtained with a collection rate of 81%.

[0291] Next, the UV-VIS absorption spectrum (hereinafter referred to simply as "absorption spectrum") and emission spectrum of a toluene solution and a solid thin film of BBABnf were measured. The measurement was performed using an apparatus and method similar to those used for the measurement of BnfABP. Fig. 18 shows the measurement results of the absorption and emission spectra of the obtained toluene solution and Fig. Figure 19 shows the measurement results of the absorption and emission spectra of the obtained thin film.

[0292] From Fig. 18, the toluene solution of BBABnf exhibits an absorption peak at about 343 nm and an emission peak at 420 nm (excitation wavelength: 340 nm).

[0293] From Fig. 19, the thin film of BBABnf exhibits absorption peaks at approximately 344 nm, 325 nm and 257 nm and an emission peak at 439 nm (excitation wavelength: 361 nm).

[0294] The HOMO and LUMO levels of BBABnf were determined by cyclic voltammetry (CV) measurements. The calculation method is similar to that described in Example 1.

[0295] As a result, the HOMO level of BBABnf was found to be -5.56 eV and its LUMO level was -2.51 eV. The peak intensity of the oxidation-reduction wave after the 100th cycle was 90% of that of the oxidation-reduction wave in the first cycle, indicating that BBABnf is extremely resistant to oxidation. The TG-DTA measurement and DSC measurement of BBABnf were performed in a similar manner to that of BnfABP. Note that the temperature was raised to 330 °C in the DSC measurement. The TG-DTA measurement revealed that the temperature for 5% weight loss of BBABnf was approximately 410 °C. This indicates that BBABnf has high thermal stability. The DSC measurement showed that the glass transition temperature of BBABnf was 117 °C and thus it had high heat resistance. [Example 3]

[0296] In this example, a light-emitting element 1 of an embodiment of the present invention, which was described in Embodiment 1, will be described. Structural formulas of organic compounds used for the light-emitting element 1 are shown below. (Method for manufacturing the light-emitting element 1)

[0297] First, a film of indium tin oxide containing silicon oxide (ITSO) was formed by a sputtering method over a glass substrate to form the anode 101. Its thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0298] Next, in a pretreatment for forming the light-emitting element over the substrate, a surface of the substrate was washed with water and baked at 200 °C for one hour, and then UV-ozone treatment was performed for 370 seconds.

[0299] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 10 -4 Pa, vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0300] Next, the substrate provided with the anode 101 was attached to a substrate holder provided in the vacuum evaporation device such that the side on which the anode 101 had been formed faced downward. Then, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), represented by structural formula (i), was deposited over the anode 101 to a thickness of 5 nm by an evaporation method using resistance heating, thereby forming the hole-injection layer 111.

[0301] Next, N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF), represented by the structural formula (ii), was deposited by evaporation to a thickness of 25 nm over the hole injection layer 111, and N,N-bis(biphenyl-4-yl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), represented by the structural formula (iii), was deposited by evaporation to a thickness of 5 nm, thereby forming the hole transport layer 112.

[0302] Then, the light-emitting layer 113 was formed by co-evaporating 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), represented by the structural formula (iv), and N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), represented by the structural formula (v), in a weight ratio of 1 : 0.03 (= cgDBCzPA : 1,6mMemFLPAPrn) to a thickness of 25 nm.

[0303] Thereafter, cgDBCzPA was deposited by evaporation to a thickness of 10 nm over the light-emitting layer 113, and then bathophenanthroline (abbreviation: BPhen) represented by the structural formula (vi) was deposited by evaporation to a thickness of 15 nm, thereby forming the electron-transport layer 114.

[0304] After forming the electron-transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron-injection layer 115. Then, aluminum was evaporated to a thickness of 200 nm to form the cathode 102. Thus, the light-emitting element 1 of this example was fabricated.

[0305] The element structure of the light-emitting element 1 is shown in the table below. [Table 1] Lochinjektionsschicht Lochtransportschicht Lichtemittierende Schicht Elektronentransportschicht Elektroneninjektionsschicht 5 nm 25 nm 5 nm 25 nm 10nm 15nm 1 nm HAT-CN PCBB F BBABnf cgDBCzPA: 1,6mMemFLPAPm (1:0,03) cgDBCzPA BPhen LF

[0306] The light-emitting element 1 was sealed using a glass substrate in a nitrogen atmosphere to prevent exposure to air (specifically, a sealing material was applied to enclose the element, and during sealing, UV treatment and heat treatment at 80°C for 1 hour were performed). Then, the initial characteristics and reliability of the light-emitting element were measured. Note that the measurements were conducted at room temperature (in an atmosphere maintained at 25°C).

[0307] Fig. Figure 20 shows the luminance-current density characteristics of the light-emitting element 1. Fig. Figure 21 shows the power efficiency-luminance characteristics of the light-emitting element 1. Fig. Figure 22 shows the luminance-voltage characteristics of the light-emitting element 1. Fig. Figure 23 shows the current-voltage characteristics of the light-emitting element 1. Fig. Figure 24 shows the external quantum efficiency-luminance characteristics of the light-emitting element 1. Fig. 25 shows the emission spectrum of the light-emitting element 1. Table 2 shows the main properties of the light-emitting element 1 at about 1000 cd / m 2 . [Table 2] Spannung V) Current (mA) Current density (mA / cm 2 ) Chromaticity x Chromaticity current y external quantum efficiency (%) 2,9 0,18 5 0,14 0,16 12,4 10,8

[0308] Out of Fig. 20 to Fig. 25 and Table 2, it has been found that the light-emitting element 1 of an embodiment of the present invention is a blue light-emitting element having a suitable efficiency and a low driving voltage.

[0309] Fig. Figure 26 shows a variation in the luminance of the light-emitting element as a function of operating time under the following conditions: The current value was set to 2 mA and the current density was constant. As shown in Fig. 26, it has been found that the light-emitting element is a long-life light-emitting element in which the reduction in luminance with the operating time is small. [Example 4]

[0310] In this example, light-emitting elements 2 and 3 of an embodiment of the present invention, which were described in Embodiment 1, are described. Structural formulas of organic compounds used for the light-emitting elements 2 and 3 are shown below. (Method for manufacturing the light-emitting element 2)

[0311] First, a film of indium tin oxide containing silicon oxide (ITSO) was formed by a sputtering method over a glass substrate to form the anode 101. Its thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0312] Next, in a pretreatment for forming the light-emitting element over the substrate, a surface of the substrate was washed with water and baked at 200 °C for one hour, and then UV-ozone treatment was performed for 370 seconds.

[0313] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 10 -4 Pa, vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0314] Next, the substrate provided with the anode 101 was attached to a substrate holder provided in the vacuum evaporation device such that the side on which the anode 101 had been formed faced downward. Then, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), represented by structural formula (i), was deposited over the anode 101 to a thickness of 5 nm by an evaporation method using resistance heating, thereby forming the hole-injection layer 111.

[0315] Next, N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF), represented by the structural formula (ii), was deposited by evaporation to a thickness of 20 nm over the hole-injection layer 111, thereby forming the first hole-transport layer 112-1. N,N-bis(biphenyl-4-yl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), represented by the structural formula (iii), was deposited by evaporation to a thickness of 5 nm over the first hole-transport layer 112-1, thereby forming the second hole-transport layer 112-2. 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), represented by the structural formula (vii), was deposited by evaporation to a thickness of 5 nm over the second hole transport layer 112-2, thereby forming the third hole transport layer 112-3.

[0316] Then, the light-emitting layer 113 was formed by co-evaporating 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), represented by the structural formula (iv), and N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), represented by the structural formula (v), in a weight ratio of 1 : 0.03 (= cgDBCzPA : 1,6mMemFLPAPrn) to a thickness of 25 nm.

[0317] Thereafter, cgDBCzPA was deposited by evaporation to a thickness of 10 nm over the light-emitting layer 113, and then bathophenanthroline (abbreviation: BPhen) represented by the structural formula (vi) was deposited by evaporation to a thickness of 15 nm, thereby forming the electron-transport layer 114.

[0318] After forming the electron-transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron-injection layer 115. Then, aluminum was evaporated to a thickness of 200 nm to form the cathode 102. Thus, the light-emitting element 2 of this example was fabricated. (Method for manufacturing the light-emitting element 3)

[0319] The light-emitting element 3 was formed in the same manner as the light-emitting element 2, except that the second hole transport layer 112-2 was formed using N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP) instead of BBABnf.

[0320] The element structures of the light-emitting elements 2 and 3 are shown in the table below. [Table 3] Hole injection layer Hole transport layer Light-emitting layer Electron transport layer Electron injection layer 1 2 3 5 nm 20 nm 5 nm 5 nm 25 nm 10 nm 15 nm 1 nm HAT-CN PCBB F *1 PCPPn cgDBCzPA : 1.6mMemFLPAPm (1:0.03) cgDBCzPA BPhen LF *1 Light-emitting element 2: BBABnf, Light-emitting element 3: BnfBPA

[0321] Light-emitting elements 2 and 3 were sealed using a glass substrate in a nitrogen atmosphere to prevent exposure to air (specifically, a sealing material was applied to enclose the element, and during sealing, UV treatment and heat treatment at 80°C for 1 hour were performed). Then, the initial characteristics and reliability of the light-emitting elements were measured. Note that the measurements were conducted at room temperature (in an atmosphere maintained at 25°C).

[0322] Fig. Figure 27 shows the luminance-current density characteristics of the light-emitting elements 2 and 3. Fig. Figure 28 shows the power efficiency-luminance characteristics of the light-emitting elements 2 and 3. Fig. Figure 29 shows the luminance-voltage characteristics of the light-emitting elements 2 and 3. Fig.Figure 30 shows the current-voltage characteristics of the light-emitting elements 2 and 3. Fig. Figure 31 shows the external quantum efficiency-luminance characteristics of the light-emitting elements 2 and 3. Fig. 32 shows the emission spectrum of the light-emitting elements 2 and 3. Table 4 shows the main properties of the light-emitting elements 2 and 3 at about 1000 cd / m 2 . [Table 4] Voltage (V) Current (mA) Current density (mA / cm 2 ) Chromaticity x Chromaticity y Power efficiency (cd / A) external quantum efficiency (%) Light-emitting element 2 3,0 0,20 5 0,14 0,16 13,8 11,8 Light-emitting element 3 3,0 0,34 9 0,14 0,15 12,8 11,5

[0323] Out of Fig. 27 to Fig. 32 and Table 4, it has been found that the light-emitting elements 2 and 3 of an embodiment of the present invention are blue light-emitting elements with a suitable efficiency and a low driving voltage.

[0324] Fig.Figure 33 shows a variation in the luminance of the light-emitting elements as a function of operating time under the following conditions: The current value was set to 2 mA and the current density was constant. As shown in Fig. As shown in Figure 33, the light-emitting elements 2 and 3 maintained 94% or more of the initial luminance after 40 hours of operation, and they were found to be long-life light-emitting elements whose luminance decreases only slightly with the lapse of time. [Example 5]〈〈Synthesis Example 3〉〉

[0325] This synthesis example demonstrates an example for synthesizing N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), which is the organic compound of one embodiment of the present invention, represented by the structural formula (229) in the embodiment. The structural formula of BBABnf(6) is as follows. <Schritt 1: Synthese von 6-Jodbenzo[b]naphtho[1,2-d]furan>

[0326] The synthesis step of 6-iodobenzo[b]naphtho[1,2-d]furan is similar to step 1 in Synthesis Example 1 in Example 1. <Schritt 2: Synthese von BBABnf(6)>

[0327] In a 200 mL three-necked flask, 2.7 g (8.0 mmol) of 6-iodobenzo[b]naphtho[1,2,-d]furan obtained in step 1, 2.6 g (8.0 mmol) of bis(1,1'-biphenyl-4-yl)amine, 0.19 g (0.40 mmol) of 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (abbreviation: X-Phos), and 1.5 g (15 mmol) of sodium tert-butoxide were added. The air in the flask was replaced with nitrogen, and then 40 mL of xylene was added. After this mixture was degassed under reduced pressure, the temperature was adjusted to 80 °C under a nitrogen stream, 0.11 g (0.20 mmol) of bis(dibenzylideneacetone)palladium(0) was added, and this mixture was stirred at 120 °C for 3 hours and further stirred at 140 °C for 6.5 hours. After stirring, the resulting mixture was washed with water and a saturated aqueous sodium chloride solution, and the organic layer was dried with magnesium sulfate.After the magnesium sulfate was removed by gravity filtration, the resulting filtrate was concentrated to obtain a brown solid. The resulting solid was purified by high-performance liquid chromatography (mobile phase: chloroform) to obtain 3.4 g of the light yellow solid of the target substance in a yield of 79%. A synthesis scheme (d-3) of step 2 is shown below.

[0328] Below are 1 H-NMR data of the obtained light yellow solid are shown. Fig. 36A and Fig. 36B are 1 H-NMR diagrams. It should be noted that Fig. 36B is a diagram showing an enlarged portion of Fig. 36A in the range of 7.00 ppm to 9.00 ppm. These results indicate that BBABnf(6), which is the organic compound of one embodiment of the present invention, was obtained in this synthesis example. 1H-NMR (chloroform-d, 500 MHz): δ = 7.25 (d, J = 8.5 Hz, 4H), 7.31 (t, J = 7.5 Hz, 2H), 7.41-7.48 (m, 6H), 7.51-7.54 (m, 6H), 7.60 (d, J = 8.0 Hz, 4H), 7.67 (t, J = 7.5 Hz, 1H), 7.73 (s, 1H), 7.88 (d, J = 8.0 Hz, 1H), 8.42 (d, J = 7.0 Hz, 1H), 6.83 (d, J = 8.0 Hz, 1H)

[0329] 3.4 g of the resulting light yellow solid was purified by sublimation. The sublimation purification was carried out for 15 hours at a temperature of 275 °C under a pressure of 3.8 Pa with an argon gas flow rate of 15 ml / min. After sublimation purification, 3.0 g of the yellow solid of the target substance was obtained with a collection rate of 87%.

[0330] Next, the UV-VIS absorption spectrum (hereinafter referred to simply as "absorption spectrum") and emission spectrum of a toluene solution and a solid thin film of BBABnf(6) were measured. The measurement was performed using an apparatus and method similar to those used in the measurement in Example 1. Fig. 37 shows the measurement results of the absorption and emission spectra of the obtained toluene solution and Fig. 38 shows the measurement results of the absorption and emission spectra of the obtained thin film.

[0331] From Fig. 37, the toluene solution of BBABnf(6) exhibits an absorption peak at about 382 nm and an emission peak at 429 nm (excitation wavelength: 337 nm).

[0332] From Fig. 38, the thin film of BBABnf(6) exhibits an absorption peak at about 390 nm and an emission peak at 453 nm (excitation wavelength: 390 nm). [Example 6]〈〈Synthesis Example 4〉〉

[0333] This synthesis example demonstrates an example for synthesizing N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), which is the organic compound of one embodiment of the present invention, represented by structural formula (189) in the embodiment. The structural formula of BBABnf(8) is as follows. <Schritt 1: Synthese von BBABnf(8)>

[0334] 2.0 g (8.0 mmol) of 8-chlorobenzo[b]naphtho[1,2-d]furan, 2.6 g (8.0 mmol) of bis(1,1'-biphenyl-4-yl)amine, 0.19 g (0.40 mmol) of 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl (abbreviation: X-Phos), and 1.5 g (15 mmol) of sodium tert-butoxide were added to a 200 mL three-necked flask. The air in the flask was replaced with nitrogen, and then 40 mL of xylene was added. After this mixture was degassed under reduced pressure, the temperature was adjusted to 80 °C under a nitrogen stream, 0.11 g (0.20 mmol) of bis(dibenzylideneacetone)palladium(0) was added, and this mixture was stirred at 120 °C for 3 hours and further stirred at 140 °C for 6.5 hours. After stirring, the resulting mixture was heated to 120 °C and filtered through Celite (catalog number 537-02305, manufactured by Wako Pure Chemical Industries, Ltd.), Florisil (catalog number 066-05265, manufactured by Wako Pure Chemical Industries, Ltd.), and alumina without cooling.The resulting filtrate was concentrated to obtain a light brown solid. The resulting solid was purified by high-performance liquid chromatography (mobile phase: chloroform) to obtain 2.9 g of the light yellow solid of the target substance in a yield of 68%. A synthesis scheme (d-4) of step 1 is shown below.

[0335] Below are 1 H-NMR data of the obtained light yellow solid are shown. Fig. 39A and Fig. 39B are 1 H-NMR diagrams. It should be noted that Fig. 39B is a diagram showing an enlarged portion of Fig. 39A in the range of 7.00 ppm to 9.00 ppm. These results indicate that BBABnf(8), which is the organic compound of one embodiment of the present invention, was obtained. 1H-NMR (chloroform-d, 500 MHz): δ = 7.23 (d, J = 8.5 Hz, 4H), 7.31 (t, J = 7.5 Hz, 2H), 7.36 (d, J = 8.0 Hz, 1H), 7.42 (t, J = 8.0 Hz, 4H), 7.47 (d, J = 8.0 Hz, 1H), 7.52 (d, J = 9.0 Hz, 4H), 7.56 (t, J = 7.5 Hz, 1H), 7.59-7.61 (m, 5H), 7.74 (t, J = 8.5 Hz, 1H), 7.87 (d, J = 8.0 Hz, 1H), 8.01 (d, J = 8.0 Hz, 1H), 8.25 (d, J = 8.0 Hz, 1H), 8.65 (d, J = 8.0 Hz, 1H)

[0336] 3.9 g of the resulting light yellow solid was purified by sublimation. The sublimation purification was carried out for 15 hours at a temperature of 275 °C under a pressure of 3.8 Pa with an argon gas flow rate of 15 ml / min. After sublimation purification, 2.1 g of the yellow solid of the target substance was obtained with a collection rate of 72%.

[0337] Next, the UV-VIS absorption spectrum (hereinafter referred to simply as "absorption spectrum") and emission spectrum of a toluene solution and a solid thin film of BBABnf(8) were measured. The measurement was performed using an apparatus and method similar to those used in the measurement in Example 1. Fig. 40 shows the measurement results of the absorption and emission spectra of the obtained toluene solution and Fig. 41 shows the measurement results of the absorption and emission spectra of the obtained thin film.

[0338] From Fig. Starting from 40, the toluene solution of BBABnf(8) exhibits an absorption peak at about 337 nm and an emission peak at 410 nm (excitation wavelength: 337 nm).

[0339] From Fig. 41, the thin film of BBABnf(8) exhibits an absorption peak at about 370 nm and an emission peak at 431 nm (excitation wavelength: 358 nm). [Example 7]

[0340] In this example, light-emitting elements 4 and 5 of one embodiment of the present invention, which were described in Embodiment 1, are described. Structural formulas of organic compounds used for the light-emitting elements 4 and 5 are shown below. (Method for manufacturing the light-emitting element 4)

[0341] First, a film of indium tin oxide containing silicon oxide (ITSO) was formed by a sputtering method over a glass substrate to form the anode 101. Its thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0342] Next, in a pretreatment for forming the light-emitting element over the substrate, a surface of the substrate was washed with water and baked at 200 °C for one hour, and then UV-ozone treatment was performed for 370 seconds.

[0343] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 10 -4 Pa, vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0344] Next, the substrate provided with the anode 101 was attached to a substrate holder provided in the vacuum evaporation device such that the side on which the anode 101 had been formed faced downward. Then, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), represented by structural formula (i), was deposited over the anode 101 to a thickness of 5 nm by an evaporation method using resistance heating, thereby forming the hole-injection layer 111.

[0345] Next, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), represented by the structural formula (ix), was deposited by evaporation to a thickness of 10 nm over the hole-injection layer 111, thereby forming the first hole-transport layer 112-1, N,N-di(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), which is the organic compound of one embodiment of the present invention and represented by the structural formula (229), was deposited by evaporation to a thickness of 10 nm over the first hole-transport layer 112-1, thereby forming the second hole-transport layer 112-2, and 3,6-bis[4-(2-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: βNP2PC)), represented by the structural formula (x), was deposited by evaporation to a thickness of 10 nm over the second hole transport layer 112-2, thereby forming the third hole transport layer 112-3.

[0346] Then, the light-emitting layer 113 was formed by co-evaporating 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), represented by the structural formula (iv), and N,N-bis(3-methylphenyl)-N,N-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), represented by the structural formula (v), in a weight ratio of 1:0.03 (= cgDBCzPA:1,6mMemFLPAPrn) to a thickness of 25 nm.

[0347] Thereafter, cgDBCzPA was deposited by evaporation to a thickness of 10 nm over the light-emitting layer 113, and then bathophenanthroline (abbreviation: BPhen) represented by the structural formula (vi) was deposited by evaporation to a thickness of 15 nm, thereby forming the electron-transport layer 114.

[0348] After forming the electron-transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron-injection layer 115. Then, aluminum was evaporated to a thickness of 200 nm to form the cathode 102. Thus, the light-emitting element 4 of this example was fabricated. (Method for manufacturing the light-emitting element 5)

[0349] The light-emitting element 5 was formed in the same manner as the light-emitting element 4, except that the second hole transport layer 112-2 was formed using N,N-di(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)) instead of BBABnf(6).

[0350] The element structures of the light-emitting elements 4 and 5 are shown in the table below. [Table 5] Hole injection layer Hole transport layer Light-emitting layer Electron transport layer Electron injection layer 1 2 3 5 nm 10 nm 10 nm 10 nm 25 nm 10 nm 15 nm 1 nm HAT-CN NPB ∗2 βN P2PC cgDBCzPA: 1.6mMemFLPAPm (1:0.03) cgDBCzPA BPhen LF ∗2 Light-emitting element 4: BBABnf(6), Light-emitting element 5: BBABnf(8)

[0351] Light-emitting elements 4 and 5 were sealed using a glass substrate in a nitrogen atmosphere to prevent exposure to air (specifically, a sealing material was applied to enclose the element, and during sealing, UV treatment and heat treatment at 80°C for 1 hour were performed). Then, the initial characteristics and reliability of the light-emitting elements were measured. Note that the measurements were conducted at room temperature (in an atmosphere maintained at 25°C).

[0352] Fig. Figure 42 shows the luminance-current density characteristics of the light-emitting elements 4 and 5. Fig. Figure 43 shows the power efficiency-luminance characteristics of the light-emitting elements 4 and 5. Fig. Figure 44 shows the luminance-voltage characteristics of the light-emitting elements 4 and 5. Fig.Figure 45 shows the current-voltage characteristics of the light-emitting elements 4 and 5. Fig. Figure 46 shows the external quantum efficiency-luminance characteristics of the light-emitting elements 4 and 5. Fig. Figure 47 shows the emission spectrum of light-emitting elements 4 and 5. Table 6 shows the main properties of light-emitting elements 4 and 5 at about 1000 cd / m 2 . [Table 6] Voltage (V) Current (mA) Current density in (A / cm 2 ) Chromaticity x Chromaticity y Power efficiency (cd / A) external quantum efficiency (%) Light-emitting element4 3,30 0,30 7,60 0,14 0,17 13,4 11,7 Light-emitting element5 3,30 0,31 7,74 0,14 0,15 13,0 11,5

[0353] Out of Fig. 42 to Fig. 46 and Table 6, it has been found that the light-emitting elements 4 and 5 of an embodiment of the present invention are blue light-emitting elements with a suitable efficiency and a low driving voltage.

[0354] Fig.Figure 48 shows a variation in the luminance of the light-emitting elements as a function of operating time under the following conditions: The current value was set to 2 mA and the current density was constant. As shown in Fig. As shown in Figure 48, the light-emitting elements 4 and 5 maintained 85% or more of the initial luminance after 100 hours of operation, and they were found to be long-life light-emitting elements whose luminance decreases only slightly with the lapse of time. [Example 8]

[0355] In this example, light-emitting elements 6 and 7 of one embodiment of the present invention, which were described in Embodiment 1, are described. Structural formulas of organic compounds used for the light-emitting elements 6 and 7 are shown below. (Method for manufacturing the light-emitting element 6)

[0356] First, a film of indium tin oxide containing silicon oxide (ITSO) was formed by a sputtering method over a glass substrate to form the anode 101. Its thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0357] Next, in a pretreatment for forming the light-emitting element over the substrate, a surface of the substrate was washed with water and baked at 200 °C for one hour, and then UV-ozone treatment was performed for 370 seconds.

[0358] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 10 -4 Pa, vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0359] Next, the substrate provided with the anode 101 was attached to a substrate holder provided in the vacuum evaporation device such that the side on which the anode 101 had been formed faced downward. Then, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), represented by structural formula (i), was deposited over the anode 101 to a thickness of 5 nm by an evaporation method using resistance heating, thereby forming the hole-injection layer 111.

[0360] Next, 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), represented by structural formula (ix), was deposited by evaporation to a thickness of 20 nm over the hole-injection layer 111, thereby forming the first hole-transport layer 112-1; N,N-di(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), which is the organic compound of one embodiment of the present invention and represented by structural formula (229), was deposited by evaporation to a thickness of 10 nm over the first hole-transport layer 112-1, thereby forming the second hole-transport layer 112-2.

[0361] Then, the light-emitting layer 113 was formed by co-evaporating 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), represented by the structural formula (iv), and N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), represented by the structural formula (v), in a weight ratio of 1 : 0.03 (= cgDBCzPA : 1,6mMemFLPAPrn) to a thickness of 25 nm.

[0362] Thereafter, cgDBCzPA was deposited by evaporation to a thickness of 10 nm over the light-emitting layer 113, and then bathophenanthroline (abbreviation: BPhen) represented by the structural formula (vi) was deposited by evaporation to a thickness of 15 nm, thereby forming the electron-transport layer 114.

[0363] After forming the electron-transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron-injection layer 115. Then, aluminum was evaporated to a thickness of 200 nm to form the cathode 102. Thus, the light-emitting element 6 of this example was fabricated. (Method for manufacturing the light-emitting element 7)

[0364] The light-emitting element 7 was formed in the same manner as the light-emitting element 6, except that the second hole transport layer 112-2 was formed using N,N-di(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)) instead of BBABnf(6).

[0365] The element structures of the light-emitting elements 6 and 7 are shown in the table below. [Table 7] Hole injection layer Hole transport layer Light-emitting layer Electron transport layer Electron absorption layer 5 nm 20 nm 10 nm 25 nm 10 nm 15 nm 1 nm HAT-CN NPB ∗3 cgDBezPA: 1.6mmMemFLPAPm (1:0.03) cgDBCzPA BPhen LF ∗3 Light-emitting element6 : BBABnf(6), Light-emitting element7 : BBABnf(8)

[0366] The light-emitting elements 6 and 7 were sealed using a glass substrate in a nitrogen atmosphere to prevent exposure to air (specifically, a sealing material was applied to enclose the element, and during sealing, UV treatment and heat treatment at 80°C for 1 hour were performed). Then, the initial characteristics and reliability of the light-emitting elements were measured. Note that the measurements were conducted at room temperature (in an atmosphere maintained at 25°C).

[0367] Fig. Figure 49 shows the luminance-current density characteristics of the light-emitting elements 6 and 7. Fig. Figure 50 shows the power efficiency-luminance characteristics of the light-emitting elements 6 and 7. Fig. 51 shows the luminance-voltage characteristics of the light-emitting elements 6 and 7. Fig.52 shows the current-voltage characteristics of the light-emitting elements 6 and 7. Fig. Figure 53 shows the external quantum efficiency-luminance characteristics of the light-emitting elements 6 and 7. Fig. Figure 54 shows the emission spectrum of the light-emitting elements 6 and 7. Table 8 shows the main properties of the light-emitting elements 6 and 7 at about 1000 cd / m 2 . [Table 8] Voltage (V) Current (mA) Current density (m A / cm 2 ) Chromaticity x Chromaticity Stromy efficiency (cd / A) external quantum efficiency (%) Light-emitting element6 3,10 0,33 8,27 0,14 0,16 12,0 10,1 Light-emitting element7 3,10 0,31 7,80 0,14 0,15 11,9 10,9

[0368] Out of Fig. 49 to Fig. 54 and Table 8, it has been found that the light-emitting elements 6 and 7 of an embodiment of the present invention are blue light-emitting elements with a suitable efficiency and a low driving voltage. [Example 9]

[0369] In this example, a light-emitting element 8 of one embodiment of the present invention, which was described in Embodiment 1, will be described. Structural formulas of organic compounds used for the light-emitting element 8 are shown below. (Method for manufacturing the light-emitting element 8)

[0370] First, a film of indium tin oxide containing silicon oxide (ITSO) was formed by a sputtering method over a glass substrate to form the anode 101. Its thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0371] Next, in a pretreatment for forming the light-emitting element over the substrate, a surface of the substrate was washed with water and baked at 200 °C for one hour, and then UV-ozone treatment was performed for 370 seconds.

[0372] The substrate was then transferred to a vacuum evaporation device where the pressure was increased to approximately 10 -4 Pa, vacuum baking was performed at 170 °C for 30 minutes in a heating chamber of the vacuum evaporation device, and then the substrate was cooled for approximately 30 minutes.

[0373] Next, the substrate provided with the anode 101 was fixed to a substrate holder provided in the vacuum evaporation apparatus such that the side on which the anode 101 had been formed was facing downward. Then, N,N-bis(biphenyl-4-yl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), which is the organic compound of one embodiment of the present invention and represented by the structural formula (146), and 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), which is represented by the structural formula (xi), were deposited by co-evaporation to a thickness of 10 nm over the anode 101 in a weight ratio of 2:1 (= BBABnf:F6-TCNNQ), thereby forming the hole-injection layer 111.

[0374] Next, BBABnf was deposited by evaporation to a thickness of 10 nm over the hole injection layer 111 to a thickness of 10 nm, thereby forming the first hole transport layer 112-1, and 3-[4-(9-phenanthryl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), represented by the structural formula (vii), was deposited by evaporation to a thickness of 20 nm over the first hole transport layer 112-1, thereby forming the second hole transport layer 112-2.

[0375] Then, the light-emitting layer 113 was formed by co-evaporating 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) represented by the structural formula (iv) and N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn) represented by the structural formula (v) in a weight ratio of 1:0.03 (= cgDBCzPA:1,6mMemFLPAPrn) to a thickness of 25 nm.

[0376] Thereafter, 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) represented by the structural formula (xii) was deposited by evaporation to a thickness of 10 nm over the light-emitting layer 113, and then 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the structural formula (xiii) was deposited by evaporation to a thickness of 15 nm, thereby forming the electron-transport layer 114.

[0377] After forming the electron-transport layer 114, lithium fluoride (LiF) was deposited by evaporation to a thickness of 1 nm to form the electron-injection layer 115. Then, aluminum was deposited by evaporation to a thickness of 200 nm to form the cathode 102. In this way, the light-emitting element 8 of this example was manufactured.

[0378] The element structure of the light-emitting element 8 is shown in the table below. [Table 9] Hole injection layer Hole transport layer Light-emitting layer Electron transport layer Electron injection layer 10 nm 10 20 nm 25 nm 10 nm 15 nm 1 nm BBABnf: F6-TCNNQ (1:0.5) BBABnf PCPPn cgDBCzPA: 1.6m MemFLPAPm (1:0.03) 2mDBTBPDBq-II NBPhen LF

[0379] The light-emitting element 8 was sealed using a glass substrate in a nitrogen atmosphere to prevent exposure to air (specifically, a sealing material was applied to enclose the element, and during sealing, UV treatment and heat treatment at 80°C for 1 hour were performed). Then, the initial characteristics and reliability of the light-emitting element were measured. Note that the measurements were conducted at room temperature (in an atmosphere maintained at 25°C).

[0380] Fig. 55 shows the luminance-current density characteristics of the light-emitting element 8. Fig.56 shows the power efficiency-luminance characteristics of the light-emitting element 8. Fig. 57 shows the luminance-voltage characteristics of the light-emitting element 8. Fig. 58 shows the current-voltage characteristics of the light-emitting element 8. Fig. Figure 59 shows the external quantum efficiency-luminance characteristics of the light-emitting element 8. Fig. 60 shows the emission spectrum of the light-emitting element 8. Table 10 shows the main properties of the light-emitting element 8 at about 1000 cd / m 2 . [Table 10] Voltage (V) Current (mA) Current density (m(A / cm) 2 ) Chromaticity x Chromaticity y Power efficiency (cd / A) external quantum efficiency (%) Light-emitting element8 3,30 0,31 7,65 0,14 0,16 14,2 12,2

[0381] Out of Fig. 55 to Fig. 60 and Table 10, it has been found that the light-emitting element 8 of an embodiment of the present invention is a blue light-emitting element having a suitable efficiency and a low driving voltage.

[0382] Fig.Figure 61 shows a variation in the luminance of the light-emitting element as a function of operating time under the following conditions: The current value was set to 2 mA and the current density was constant. As shown in Fig. 61, the light-emitting element 8 maintained 90% or more of the initial luminance after 100 hours of operation, and it was found to be a light-emitting element with a long lifetime and little decrease in luminance with the lapse of time. Reference symbol

[0383] 101: Anode 102: Cathode 103: EL layer 111: Hole injection layer 112: Hole transport layer 112-1: First hole transport layer 112-2: Second hole transport layer 112-3: Third hole transport layer 113: Light-emitting layer 114: Electron transport layer 115: Electron injection layer 116: Charge generation layer 117: P-type layer 118: Electron relay layer 119: Electron injection buffer layer 400: Substrate 401: Anode 403: EL layer 404: Cathode 405: Sealing material 406: Sealing material 407: Sealing substrate 412: Contact pad 420: IC chip 501: Anode 502: Cathode 511: First light-emitting unit 512: Second Light-emitting unit 513: Charge generation layer 601: Driver circuit section (source line driver circuit) 602: Pixel section 603: Driver circuit section (gate line driver circuit) 604: Sealing substrate 605: Sealing material 607: Space 608: Line 609: FPC (flexible printed circuit) 610: Element substrate 611: Switching FET612: Current controlling FET 613: Anode 614: Insulator 616: EL layer 617: Cathode 618: Light-emitting element 730: Insulating film 770: Insulating planarization film 772: Conductive film 782: Light-emitting element 783: Droplet ejector 784: Droplet 785: Layer 786: EL layer 788: Conductive film 901: Case 902: Liquid crystal layer 903: Backlight unit 904: Case 905: Driver IC 906: Terminal 951: Substrate 952: Electrode 953: Insulating layer 954: Separator layer 955: EL layer 956: Electrode 1001: Substrate 1002: Base insulating film 1003: Gate insulating film 1006: Gate electrode 1007: Gate electrode 1008: Gate electrode 1020: First interlayer insulating film 1021: Second interlayer insulating film 1022: Electrode 1024W: Anode 1024R: Anode 1024G: Anode 1024B: Anode 1025: Partition 1028: EL layer 1029: Cathode 1031: Sealing substrate 1032: Sealing material 1033: Transparent base material 1034R: Red color layer 1034G: GreenColor layer 1034B: blue color layer 1035: black matrix 1036: capping layer 1037: third interlayer insulating film 1040: pixel section 1041: driving circuit section 1042: peripheral section 1400: droplet ejection device 1402: substrate 1403: droplet ejection means 1404: imaging means 1405: head 1406: dotted line 1407: control means 1408: storage medium 1409: image processing means 1410: computer 1411: marker 1412: head 1413: material supply source 1414: material supply source 1415: material supply source 1416: head 2001: housing 2002: light source 3001: illumination device 5000: Display section 5001: Display section 5002: Display section 5003: Display section 5004: Display section 5005: Display section 7101: Housing 7103: Display section 7105: Stand 7107: Display section 7109: Operation button 7110: Remote control 7201: Main body 7202: Housing 7203: Display section 7204: Keypad 7205: External connection port 7206: Pointing device 7210: SecondDisplay section 7301: Housing 7302: Housing 7303: Joint part 7304: Display section 7305: Display section 7306: Speaker section 7307: Recording media insertion section 7308: LED lamp 7309: Operation button 7310: Connection terminal 7311: Sensor 7401: Housing 7402: Display section 7403: Operation knob 7404: External connection terminal 7405: Speaker 7406: Microphone 7400: Mobile phone 9033: Clasp 9034: Switch 9035: Power switch 9036: Switch 9038: Operation switch 9310: Portable information terminal 9311: Display screen 9312: Display section 9313: Joint 9315: Housing 9630: Housing 9631: Display section 9631a: Display section 9631b: Display section 9632a: Touch screen area 9632b: Touch screen area 9633: Solar cell 9634: Charge and discharge control circuit 9635: Battery 9636: DC-DC converter 9637: Control button 9638: Converter 9639: Button

Claims

[1] A hole transport material comprising an organic compound, wherein the organic compound is represented by the general formula (G1), where R 1 to R 8 independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where R 2 is not an amino group; wherein one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where Ar 1 and Ar 2 independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms or a group represented by the general formula (g2), where Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton, where R 11 to R 18independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and where one of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. [2] The hole transport material according to claim 1, wherein in the case where Ar 1 and Ar 2 each are an aromatic hydrocarbon group having 6 to 60 carbon atoms and comprise a substituent, the substituent comprising a benzonaphthofuranyl group and a dinaphthofuranyl group. [3] A light-emitting element comprising: an anode (101); a cathode (102); and an EL layer (103), wherein the EL layer (103) comprises a light-emitting layer (113), wherein the EL layer (103) is positioned between the anode (101) and the cathode (102), and wherein the EL layer (103) comprises the hole transport material according to claim 1. [4] The light-emitting element according to claim 3, wherein the light-emitting layer (113) comprises a light-emitting material and the hole-transporting material. [5] The light-emitting element according to claim 4, wherein the light-emitting layer (113) further comprises an electron transport material. [6] An organic compound represented by the general formula (G1), where R 1 to R 8 independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where R 2 is not an amino group, wherein one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where Ar 1 and Ar 2independently represent an unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted aromatic hydrocarbon group having 6 to 60 carbon atoms substituted by a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a dibenzofuranyl group or a benzonaphthofuranyl group, or a group represented by the general formula (g2), where Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton, where R 11 to R 18independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and where one of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms. [7] An organic compound represented by the general formula (G1), where R 1 to R 8 independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and wherein one of A and B represents a group represented by the general formula (g1), and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms, or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where Ar 1 and Ar 2 independently represent a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms or a group represented by the general formula (g2), where Ar 1 and Ar 2 do not contain a dibenzothiophene skeleton, where R 11 to R 18independently of one another represent hydrogen, a hydrocarbon group having 1 to 6 carbon atoms, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, where one of Z 1 and Z 2 is bonded to a nitrogen atom in the general formula (g1) and the other represents hydrogen, a cyclic hydrocarbon group having 3 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, halogen, a haloalkyl group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms or a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, and wherein the organic compound does not have two or more substituted or unsubstituted amine skeletons. [8] The organic compound according to claim 6 or 7, wherein in the case where Ar 1 and Ar 2 each are an aromatic hydrocarbon group having 6 to 60 carbon atoms and comprise a substituent, the substituent comprising a benzonaphthofuranyl group and a dinaphthofuranyl group. [9] A light-emitting element comprising: an anode (101); a cathode (102); and an EL layer (103), wherein the EL layer (103) is positioned between the anode (101) and the cathode (102), and wherein the EL layer (103) comprises the organic compound according to claim 6 or 7. [10] The light-emitting element according to claim 9, wherein the EL layer (103) further comprises a light-emitting layer (113) comprising a light-emitting material. [11] The light-emitting element according to claim 9, wherein the EL layer further comprises a light-emitting layer (113) comprising a material having an electron-transport property. [12] A light-emitting element comprising: an anode (101); a cathode (102); and an EL layer (103) comprising a hole injection layer (111), wherein the EL layer (103) is positioned between the anode (101) and the cathode (102), wherein the EL layer (103) comprises a light-emitting layer (113) and a hole-transporting layer (112), wherein the hole transport layer (112) is positioned between the light-emitting layer (113) and the anode (101), wherein the hole injection layer (111) is in contact with the anode (101) and the hole transport layer (112), wherein the hole injection layer (111) comprises an organic compound having an acceptor property, and wherein the hole transport layer (111) comprises the organic compound according to claim 6 or 7. [13] The light-emitting element according to claim 12, wherein the organic compound having the acceptor property is 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene. [14] The light-emitting element according to claim 12, wherein the hole transport layer (112) comprises a first layer (112-1), a second layer (112-2) and a third layer (112-3), wherein the first layer (112-1) is positioned between the hole injection layer (111) and the second layer (112-2), wherein the third layer (112-3) is positioned between the second layer (112-2) and the light-emitting layer (113), wherein the first layer (112-1) is in contact with the hole injection layer (111), wherein the third layer (112-3) is in contact with the light-emitting layer (113), wherein the first layer (112-1) comprises a first hole transport material, wherein the second layer (112-2) comprises the organic compound, wherein the third layer (112-3) comprises a third hole transport material, wherein the light-emitting layer (113) comprises a host material and a light-emitting material, where a HOMO level of the organic compound is lower than a HOMO level of the first hole transport material, where a HOMO level of the host material is lower than the HOMO level of the organic compound, and wherein a difference between the HOMO level of the organic compound and a HOMO level of the third hole transport material is less than or equal to 0.3 eV. [15] The light-emitting element according to claim 14, where the HOMO level of the first hole transport material is greater than or equal to -5.4 eV. [16] The light-emitting element according to claim 14, wherein a difference between the HOMO level of the first hole transport material and the HOMO level of the organic compound is less than or equal to 0.3 eV, wherein the difference between the HOMO level of the organic compound and the HOMO level of the third hole transport material is less than or equal to 0.2 eV, and where the difference between the HOMO level of the first hole transport material and the HOMO level of the organic compound is less than or equal to 0.2 eV. [17] The light-emitting element according to claim 14, where the HOMO level of the light-emitting material is higher than the HOMO level of the host material, and where the HOMO level of the third hole transport material is lower than or equal to the HOMO level of the host material. [18] The light-emitting element according to claim 14, wherein the light-emitting material emits blue fluorescent light. [19] The light-emitting element according to claim 14, wherein the light-emitting material is a condensed aromatic diamine compound. [20] The light-emitting element according to claim 14, wherein the light-emitting material is a diaminopyrene compound. [21] A light-emitting device comprising: the light-emitting element according to claim 14; and a transistor or a substrate.

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