ARYLAMINE COMPOUND AND ELECTRONIC APPARATUS USING SAME

Abstract

An object of the present invention is to provide a material for a highly efficient and highly durable organic EL device, and specifically, an organic compound with excellent properties including excellent hole-injecting/transporting performance, electron-blocking capability, and high stability in the form of a thin film. Another object of the present invention is to provide a highly efficient and highly durable organic EL device by using this compound. The present invention is directed to an arylamine compound having a fluorenyl skeleton-containing heterocycle structure, with excellent heat resistance and good hole-transporting capability. An organic EL device including this compound in its hole-transporting layer, electron-blocking layer, light-emitting layer, or hole-injecting layer exhibited good device characteristics.

Claims

1. An arylamine compound having a fluorenyl skeleton-containing heterocycle structure represented by a general formula (A) below: ##STR00016## where R.sub.1 to R.sub.11 is the same or different, and each represent a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a linear or branched alkyl group having 1 to 6 carbon atoms and optionally having a substituent, a cycloalkyl group having 5 to 10 carbon atoms and optionally having a substituent, a linear or branched alkenyl group having 2 to 6 carbon atoms and optionally having a substituent, a linear or branched alkyloxy group having 1 to 6 carbon atoms and optionally having a substituent, a cycloalkyloxy group having 5 to 10 carbon atoms and optionally having a substituent, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic group, or a substituted or unsubstituted aryloxy group; L represents a divalent group of a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group; n is 1 or 2, and, when n is 2, L is the same or different; Ar.sub.1 and Ar.sub.2 is the same or different, and each represent a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group; X represents an oxygen atom, a sulfur atom, or a nitrogen atom having a substituent; and L and Ar.sub.1 are optionally bonded to each other to form a ring via a single bond or a linking group selected from a substituted or unsubstituted methylene group, an oxygen atom, a sulfur atom, and a nitrogen atom having a substituent; and the same holds true for Ar.sub.1 and Ar.sub.2.

2. The arylamine compound having a fluorenyl skeleton-containing heterocycle structure as set forth in claim 1, wherein R.sub.10 and R.sub.11 are each a substituted or unsubstituted methyl group or a substituted or unsubstituted phenyl group.

3. The arylamine compound having a fluorenyl skeleton-containing heterocycle structure as set forth in claim 1, wherein X is an oxygen atom.

4. The arylamine compound having a fluorenyl skeleton-containing heterocycle structure as set forth in claim 1, wherein L is a substituted or unsubstituted phenylene group, a substituted or unsubstituted biphenylene group, or a substituted or unsubstituted naphthylene group.

5. The arylamine compound having a fluorenyl skeleton-containing heterocycle structure as set forth in claim 1, wherein n is 1.

6. An organic electroluminescence device comprising a pair of electrodes and one or more organic layers sandwiched therebetween, wherein at least one of the organic layers contains the arylamine compound having a fluorenyl skeleton-containing heterocycle structure as set forth in claim 1.

7. The organic electroluminescence device as set forth in claim 6, wherein the organic layer is an electron-blocking layer.

8. The organic electroluminescence device as set forth in claim 6, wherein the organic layer is a hole-transporting layer.

9. The organic electroluminescence device as set forth in claim 6, wherein the organic layer is a hole-injecting layer.

10. The organic electroluminescence device as set forth in claim 6, wherein the organic layer is a light-emitting layer.

11. An electronic apparatus comprising an electronic component having a pair of electrodes and one or more organic layers sandwiched therebetween, wherein at least one of the organic layers contains the arylamine compound having a fluorenyl skeleton-containing heterocycle structure as set forth in claim 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0066] FIG. 1 Compounds of (1) to (15) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0067] FIG. 2 Compounds of (16) to (30) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0068] FIG. 3 Compounds of (31) to (45) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0069] FIG. 4 Compounds of (46) to (60) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0070] FIG. 5 Compounds of (61) to (75) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0071] FIG. 6 Compounds of (76) to (90) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0072] FIG. 7 Compounds of (91) to (105) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0073] FIG. 8 Compounds of (106) to (114) as preferred specific examples of the arylamine compound represented by the general formula (A).

[0074] FIG. 9 A diagram showing an example of the configuration of the organic EL device of the present invention.

DESCRIPTION OF EMBODIMENTS

[0075] The arylamine compounds having a fluorenyl skeleton-containing heterocycle structure of the present invention are novel compounds. These compounds can be synthesized according to methods known per se (see Patent Literature 5, for example).

[0076] Specific preferred examples of the arylamine compound having a fluorenyl skeleton-containing heterocycle structure represented by the general formula (A) above and suitably used in an organic EL device of the present invention are shown in FIGS. 1 to 8. However, the arylamine compound of the present invention is not limited thereto.

[0077] The arylamine compound represented by the general formula (A) can be purified by any known purification method, such as column chromatography, adsorption with silica gel, activated carbon, activated clay, or the like, recrystallization or crystallization from a solvent, or sublimation. The compound can be identified by NMR analysis. The physical properties can be determined in terms of the melting point, the glass transition point (Tg), the work function, and others. The melting point is a measure of the vapor deposition properties. The glass transition point (Tg) is a measure of the stability in the form of a thin film. The work function is a measure of the hole injectability, the hole-transporting capability, and the electron block ability.

[0078] The melting point and the glass transition point (Tg) can be measured, for example, on the compound in the form of a powder using a high-sensitivity differential scanning calorimeter (DSC3100SA manufactured by Bruker AXS K.K.).

[0079] The work function can be determined, for example, on the compound in the form of a thin film with a thickness of 100 nm on an ITO substrate using an ionization potential measurement system (PYS-202 manufactured by Sumitomo Heavy Industries, Ltd.).

[0080] The organic EL device of the present invention may have: a structure in which an anode, a hole-injecting layer, a hole-transporting layer, a light-emitting layer, an electron-transporting layer, an electron-injecting layer, and a cathode are sequentially formed on a substrate; and the structure may further include an electron-blocking layer between the hole-transporting layer and the light-emitting layer and/or a hole-blocking layer between the light-emitting layer and the electron-transporting layer. In these multilayer structures, a single organic layer can perform the functions of several layers. For example, a single organic layer may serve as both the hole-injecting layer and the hole-transporting layer, and a single organic layer may serve as both the electron-injecting layer and the electron-transporting layer. It is also possible to stack two or more organic layers having the same function. Specifically, two hole-transporting layers may be stacked; two light-emitting layers may be stacked; and two electron-transporting layers may be stacked.

[0081] An electrode material having a high work function, such as ITO or gold, is used for the anode of the organic EL device of the present invention. Examples of the materials used for the hole-injecting layer of the organic EL device of the present invention include porphyrin compounds typified by copper phthalocyanine; starburst triphenylamine derivatives; arylamine compounds having a structure containing two or more triphenylamine structures or carbazolyl structures in the molecule, the triphenylamine or carbazolyl structures being linked via a single bond or a divalent group having no heteroatom; acceptor type heterocyclic compounds such as hexacyanoazatriphenylene; and coating type polymer materials.

[0082] Examples of the materials used for the hole-injecting layer and the hole-transporting layer of the organic EL device of the present invention include: the arylamine compound having a fluorenyl skeleton-containing heterocycle structure of the present invention; benzidine derivatives such as N,N′-diphenyl-N,N′-di(m-tolyl)-benzidine (hereinafter abbreviated as TPD), N,N′-diphenyl-N,N′-di(α-naphthyl)-benzidine (hereinafter abbreviated as NPD), and N,N,N′,N′-tetrabiphenylyl benzidine; 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (hereinafter abbreviated as TAPC); and arylamine compounds having a structure containing two or more triphenylamine structures or carbazolyl structures in the molecule, the triphenylamine or carbazolyl structures being linked via a single bond or a divalent group having no heteroatom. These materials may be used singly for film formation, or two or more of these materials may be mixed and used for film formation. In each case, a single layer may be formed. The hole-injecting layer and the hole-transporting layer may have a layered structure composed of different layers each formed of a single kind of the materials described above, a layered structure composed of different layers each formed of a mixture of the materials described above, or a layered structure composed of a layer formed of a single kind of the materials described above and a layer formed of a mixture of two or more of the materials described above. Other examples of the materials used for the hole-injecting/transporting layers include coating type polymer materials such as poly(3,4-ethylenedioxythiophene) (hereinafter abbreviated as PEDOT)/poly (styrenesulfonate) (hereinafter abbreviated as PSS).

[0083] Other examples of the materials used for the hole-injecting layer or the hole-transporting layer include a material obtained by p-doping a material normally used for these layers with trisbromophenylamine hexachloroantimony or a radialene derivative (see Patent Literature 6, for example); and a polymer compound having the structure of a benzidine derivative, such as TPD, as a partial structure thereof.

[0084] Examples of the materials used for the electron-blocking layer of the organic EL device of the present invention include: the arylamine compound having a fluorenyl skeleton-containing heterocycle structure of the present invention; and also compounds having an electron-blocking effect, such as carbazole derivatives such as 4,4′,4″-tri(N-carbazolyl)triphenylamine (hereinafter abbreviated as TCTA), 9,9-bis[4-(carbazole-9-yl)phenyl]fluorene, 1,3-bis(carbazole-9-yl)benzene (hereinafter abbreviated as mCP), and 2,2-bis(4-carbazole-9-ylphenyl)adamantane (hereinafter abbreviated as Ad-Cz); and compounds having a triphenylsilyl group and a triarylamine structure such as 9-[4-(carbazole-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene. These materials may also serve as the material used for the hole-transporting layer.

[0085] Examples of the materials of the light-emitting layer of the organic EL device of the present invention include: the arylamine compound having a fluorenyl skeleton-containing heterocycle structure of the present invention; metal complexes of quinolinol derivatives such as Alq.sub.3; various types of metal complexes; an anthracene derivative; a bisstyrylbenzene derivative; a pyrene derivative; an oxazole derivative; and a polyphenylene vinylene derivative. The light-emitting layer may also include a host material and a dopant material. As the host material, an anthracene derivative is preferably used. Other examples of the host material include the light emitting materials including the arylamine compound of the present invention, and also a heterocyclic compound having an indole ring as a partial structure of a fused ring, a heterocyclic compound having a carbazole ring as a partial structure of a fused ring, a carbazole derivative, a thiazole derivative, a benzimidazole derivative, and a polydialkylfluorene derivative. Examples of the dopant material include quinacridone, coumalin, rubrene, perylene, and derivatives thereof; a benzopyran derivative; a rhodamine derivative; and an aminostyryl derivative.

[0086] A phosphorescent emitter can also be used as a light emitting material. The phosphorescent emitter may be a metal complex of iridium, platinum, or the like, and examples thereof include a green phosphorescent emitter such as Ir(ppy).sub.3, a blue phosphorescent emitter such as FIrpic or FIr6, and a red phosphorescent emitter such as Btp.sub.2Ir (acac). As a host material for this case, a host material having hole injecting/transporting capability may be used, including carbazole derivatives such as 4,4′-di(N-carbazolyl)biphenyl (hereinafter abbreviated as CBP), TCTA, and mCP, and also the arylamine compound of the present invention. A host material having electron-transporting capability may also be used, including p-bis(triphenylsilyl)benzene (hereinafter abbreviated as UGH2) and 2,2′,2″-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (hereinafter abbreviated as TPBI). Use of these materials enables production of a high-performance organic EL element.

[0087] In order to avoid concentration quenching, doping of a host material with a phosphorescent emitter is preferably performed by co-deposition in an amount within a range of 1 to 30 wt % based on the entire light-emitting layer.

[0088] As the light emitting material, a material that emits delayed fluorescence can also be used, including a CDCB derivative such as PIC-TRZ, CC2TA, PXZ-TRZ, and 4CzIPN (see Non-Patent Literature 3, for example).

[0089] Examples of the materials used for the hole blocking layer of the organic EL device of the present invention include compounds exhibiting a hole blocking effect, including a phenanthroline derivative, such as bathocuproine (hereinafter abbreviated as BCP); a metal complex of a quinolinol derivative, such as BA1q; various types of rare-earth complexes; an oxazole derivative; a triazole derivative; and a triazine derivative. These materials may also serve as the material of the electron-transporting layer.

[0090] Examples of the material used for the electron-transporting layer of the organic EL device of the present invention include metal complexes of quinolinol derivatives, such as Alq.sub.3 and BA1q; various types of metal complexes; a triazole derivative; a triazine derivative; an oxadiazole derivative; a pyridine derivative; a pyrimidine derivative; a benzimidazole derivative; a thiadiazole derivative; an anthracene derivative; a carbodiimide derivative; a quinoxaline derivative; a pyridoindole derivative; a phenanthroline derivative; and a silole derivative.

[0091] Examples of the materials used for the electron-injecting layer of the organic EL device of the present invention include alkali metal salts such as lithium fluoride and cesium fluoride; an alkaline earth metal salt such as magnesium fluoride; a metal complex of a quinolinol derivative such as lithium quinolinol; a metal oxide such as aluminum oxide; and a metal such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), and cesium (Cs). The electron-injecting layer can however be omitted when an electron-transporting layer and a cathode are suitably selected.

[0092] Furthermore, a material obtained by n-doping a material normally used for an electron-injecting layer or an electron-transporting layer with a metal such as cesium can be used for the electron-injecting layer or the electron-transporting layer.

[0093] For the cathode of the organic EL device of the present invention, a metal having a low work function, such as aluminum; or an alloy having an even lower work function, such as a magnesium-silver alloy, a magnesium-indium alloy, or an aluminum-magnesium alloy is used as the electrode material.

[0094] These materials for the layers in the organic EL device may be used in a known method, such as vapor deposition, spin coating, or inkjet printing, to form a thin film. These materials may be used singly for film formation, or two or more of these materials may be mixed and used for film formation. In each case, a single layer film may be formed. The film may have a layered structure composed of different layers each formed of a single kind of the materials described above, a layered structure composed of different layers each formed of a mixture of the materials described above, or a layered structure composed of a layer formed of a single kind of the materials described above and a layer formed of a mixture of two or more of the materials described above.

EXAMPLES

[0095] Hereinafter, embodiments of the present invention will be described in greater detail by way of examples. However, the present invention is not limited thereto as long as it does not depart from the gist thereof.

Example 1

[0096] Synthesis of bis(biphenyl-4-yl)-{3-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene yl)-phenyl}-amine (Compound (12))

[0097] First, 7.0 g of 5-bromo-7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene, 12.1 g of bis(biphenyl-4-yl)-{3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolane-2-yl)-phenyl}-amine, 0.3 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and 2.4 g of sodium hydrogencarbonate were placed in a reaction vessel and stirred in a THF/H.sub.2O mixed solvent overnight under reflux. After allowing to cool, ethyl acetate/H.sub.2O was added to the system, and the organic layer was obtained by extraction and partition and concentrated to obtain a crude product. The obtained crude product was purified through crystallization from a dichloromethane/acetone mixed solvent to obtain 12.2 g of a white powder of bis(biphenyl-4-yl)-{3-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (12)) (yield: 92.9%).

##STR00002##

[0098] The obtained white powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 37 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.30 (1H), 7.68 (1H), 7.62 (1H), 7.61-7.50 (11H), 7.49 (1H), 7.44 (6H), 7.39 (2H), 7.33 (7H), 7.18 (1H), 1.61 (6H).

Example 2

Synthesis of biphenyl-4-yl-{4-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-phenyl-amine (Compound (14))

[0099] First, 10.0 g of 5-bromo-7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene, 9.0 g of 4-(biphenyl-4-yl-phenyl-amino)-phenylboronic acid, 0.3 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and 3.5 g of sodium hydrogencarbonate were placed in a reaction vessel and stirred in a THF/H.sub.2O mixed solvent overnight under reflux. After allowing to cool, ethyl acetate/H.sub.2O was added to the system, and the organic layer was obtained by extraction and partition and concentrated to obtain a crude product. The obtained crude product was purified through crystallization from a dichloromethane/acetone mixed solvent to obtain 8.5 g of a pale yellow powder of biphenyl-4-yl-{4-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-phenyl-amine (Compound (14)) (yield: 56.9%).

##STR00003##

[0100] The obtained pale yellow powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 37 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.38 (1H), 7.78 (1H), 7.73 (1H), 7.63 (2H), 7.56 (2H), 7.49 (7H), 7.39-7.20 (22H), 7.11 (1H).

Example 3

Synthesis of biphenyl-4-yl-{3-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-phenyl-amine (Compound (52))

[0101] First, 7.0 g of 5-bromo-7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene, 7.4 g of biphenyl-4-yl-phenyl-{3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolane-2-yl)-phenyl}-amine, 0.2 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and 2.4 g of sodium hydrogencarbonate were placed in a reaction vessel and stirred in a THF/H.sub.2O mixed solvent overnight under reflux. After allowing to cool, ethyl acetate/H.sub.2O was added to the system, and the organic layer was obtained by extraction and partition and concentrated to obtain a crude product. The obtained crude product was purified through recrystallization from an acetone solvent to obtain 8.5 g of a white powder of biphenyl-4-yl-{3-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-phenyl-amine (Compound (52)) (yield: 81.3%).

##STR00004##

[0102] The obtained white powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 37 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.35 (1H), 7.69 (1H), 7.62 (1H), 7.57 (2H), 7.54-7.19 (30H), 7.17 (1H), 7.06 (1H).

Example 4

Synthesis of bis(biphenyl-4-yl)-{4-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (7))

[0103] First, 4.0 g of 5-(4-chlorophenyl)-7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene, 4.2 g of bis(biphenyl-4-yl)-amine, 0.1 g of bis(tri-t-butylphosphine)palladium(0), and 3.0 g of sodium t-butoxide were placed in a reaction vessel and stirred in a toluene solvent overnight under reflux. After allowing to cool, the resulting system was filtered, and the filtrate was concentrated to obtain a crude product. The obtained crude product was purified through crystallization from a dichloromethane/acetone mixed solvent to obtain 5.2 g of a yellow powder of bis(biphenyl-4-yl)-{4-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (7)) (yield: 75.4%).

##STR00005##

[0104] The obtained yellow powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 37 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.29 (1H), 7.74 (1H), 7.69 (1H), 7.62 (6H), 7.58 (4H), 7.51-7.41 (7H), 7.39-7.30 (10H), 7.22 (1H), 1.60 (6H).

Example 5

Synthesis of bis(biphenyl-4-yl)-{4-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (24))

[0105] First, 8.1 g of 5-(4-chlorophenyl)-7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene, 5.5 g of bis(biphenyl-4-yl)-amine, 0.2 g of bis(tri-t-butylphosphine)palladium(0), and 3.0 g sodium t-butoxide were placed in a reaction vessel and stirred in a toluene solvent overnight under reflux. After allowing to cool, the resulting system was filtered, and the filtrate was concentrated to obtain a crude product. The obtained crude product was purified through crystallization from a monochlorobenzene/acetone mixed solvent to obtain 9.8 g of a white powder of bis(biphenyl-4-yl)-{4-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (24)) (yield: 78.1%).

##STR00006##

[0106] The obtained white powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 41 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.35 (1H), 7.75 (1H), 7.71 (1H), 7.60 (4H), 7.55 (4H), 7.51 (2H), 7.49-7.40 (7H), 7.34 (2H), 7.33-7.26 (12H), 7.25-7.18 (7H).

Example 6

Synthesis of (biphenyl-2-yl)-(biphenyl-4-yl)-{4-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (26))

[0107] First, 9.0 g of (biphenyl-4-yl)-(biphenyl-4-yl)-{4-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine, 3.9 g of 2-bromobiphenyl, 0.1 g of palladium(II) acetate, 0.2 g of tri-t-butylphosphine, and 2.0 g sodium t-butoxide were placed in a reaction vessel and stirred in a toluene solvent for 3 hours under reflux. After allowing to cool, the resulting system was filtered, and the filtrate was concentrated to obtain a crude product. The obtained crude product was purified by column chromatography (column: silica gel, eluent: dichloromethane/n-heptane) to obtain 7.6 g of a white powder of (biphenyl-2-yl)-(biphenyl-4-yl)-{4-(7,7-dimethyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (26)) (yield: 68.4%).

##STR00007##

[0108] The obtained white powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 41 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.33 (1H), 7.68 (1H), 7.55 (2H), 7.51 (1H), 7.50-7.38 (10H), 7.37-7.08 (24H), 6.91 (2H).

Example 7

Synthesis of diphenyl-{1-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-naphthalene-4-yl}-amine (Compound (43))

[0109] First, 8.7 g of 5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolane-2-yl)-7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene, 6.0 g of diphenylamino-naphthalene-4-yl-trifluoromethanesulfonate, 0.2 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and 1.7 g sodium hydrogencarbonate were placed in a reaction vessel and stirred in a THF/H.sub.2O mixed solvent overnight under reflux. After allowing to cool, methanol was added to the system to form a solid precipitate, and the precipitate was collected as a crude product by filtration. The obtained crude product was purified through crystallization from a toluene/acetone mixed solvent to obtain 4.4 g of a pale yellow powder of diphenyl-{1-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-naphthalene-4-yl}-amine (Compound (43)) (yield: 45.9%).

##STR00008##

[0110] The obtained pale yellow powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 35 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.40 (1H), 8.07 (1H), 7.68 (1H), 7.61 (1H), 7.56 (1H), 7.52 (1H), 7.50 (1H), 7.46 (1H), 7.42 (1H), 7.40-7.17 (18H), 7.13 (4H), 6.97 (3H), 6.71 (1H).

Example 8

Synthesis of bis(biphenyl-4-yl)-{3-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (61))

[0111] First, 10.0 g of 5-bromo-7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene, 12.9 g of bis(biphenyl-4-yl)-{3-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolane-2-yl)-phenyl}-amine, 0.3 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and 2.6 g sodium hydrogencarbonate were placed in a reaction vessel and stirred in a THF/H.sub.2O mixed solvent for 2 hours under reflux. After allowing to cool, ethyl acetate/H.sub.2O was added to the system, and the organic layer was obtained by extraction and partition and concentrated to obtain a crude product. The obtained crude product was purified through crystallization from a dichloromethane/acetone mixed solvent to obtain 14.5 g of a white powder of bis(biphenyl-4-yl)-{3-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-phenyl}-amine (Compound (61)) (with a yield of 87.9%).

##STR00009##

[0112] The obtained white powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 41 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.32 (1H), 7.66 (1H), 7.60 (1H), 7.55 (4H), 7.49 (4H), 7.48-7.38 (8H), 7.35 (2H), 7.32-7.26 (5H), 7.24 (8H), 7.21-7.12 (7H).

Example 9

Synthesis of bis(biphenyl-4-yl)-{5-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-biphenyl-2-yl}-amine (Compound (94))

[0113] First, 4.3 g of 5-bromo-7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene, 6.3 g of bis(biphenyl-4-yl)-5-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolane-2-yl)-biphenyl-2-ylI-amine, 0.1 g of [1,1′-bis(diphenylphosphino)ferrocene]dichloropalladium(II), and 1.1 g sodium hydrogencarbonate were placed in a reaction vessel and stirred in a THF/H.sub.2O mixed solvent for 5 hours under reflux. After allowing to cool, methanol was added to the system to form a solid precipitate, and the precipitate was collected as a crude product by filtration. The obtained crude product was purified through crystallization from a dichloromethane/acetone mixed solvent to obtain 7.1 g of a pale yellow powder of bis(biphenyl-4-yl)-{5-(7,7-diphenyl-7H-12-oxa-indeno[1,2-a]fluorene-5-yl)-biphenyl-2-yl}-amine (Compound (94)) (yield: 91.6%).

##STR00010##

[0114] The obtained pale yellow powder was analyzed by .sup.1H-NMR (CDCl.sub.3), and as a result, the following 45 hydrogen signals were detected to identify the structure thereof.

δ (ppm)=8.37 (1H), 7.79 (1H), 7.72 (1H), 7.62 (1H), 7.60 (1H), 7.53 (5H), 7.48 (3H), 7.44-7.34 (9H), 7.34-7.18 (17H), 7.07 (6H).

Example 10

[0115] The melting point and the glass transition point of each of the arylamine compounds having a fluorenyl skeleton-containing heterocycle structure obtained in the above-described examples were measured using a high-sensitivity differential scanning calorimeter (DSC3100SA manufactured by Bruker AXS K.K.). Table 1 shows the results.

TABLE-US-00001 TABLE 1 Melting point Glass transition point Compound of Ex. 1 — 123° C. Compound of Ex. 2 — 143° C. Compound of Ex. 3 232° C. 132° C. Compound of Ex. 4 267° C. 132° C. Compound of Ex. 5 298° C. 160° C. Compound of Ex. 6 305° C. 152° C. Compound of Ex. 7 340° C. 152° C. Compound of Ex. 8 265° C. 148° C. Compound of Ex. 9 271° C. 164° C.

[0116] It is seen from Table 1 that the arylamine compounds having a fluorenyl skeleton-containing heterocycle structure represented by the general formula (A) had a glass transition point of 120° C. or more, which means that these compounds were stable in the form of a thin film.

Example 11

[0117] A vapor-deposited film (thickness: 100 nm) of the arylamine compound having a fluorenyl skeleton-containing heterocycle structure in the above-described examples was formed on an ITO substrate, and the work function was measured using an ionization potential measuring system (PYS-202 manufactured by Sumitomo Heavy Industries, Ltd.). Table 2 shows the results.

TABLE-US-00002 TABLE 2 Work function Compound of Ex. 1 5.78 eV Compound of Ex. 2 5.76 eV Compound of Ex. 3 5.86 eV Compound of Ex. 4 5.73 eV Compound of Ex. 5 5.72 eV Compound of Ex. 6 5.74 eV Compound of Ex. 7 5.98 eV Compound of Ex. 8 5.78 eV Compound of Ex. 9 5.76 eV

[0118] It is seen from Table 2 that the arylamine compounds having a fluorenyl skeleton-containing heterocycle structure represented by the general formula (A) had a work function higher than common hole-transporting materials such as NPD and TPD, which have a work function of 5.4 eV, and that these arylamine compounds thus had a better energy level. This means that the arylamine compounds having a fluorenyl skeleton-containing heterocycle structure have good hole-transporting capability.

Example 12

[0119] An organic EL device having the configuration as shown in FIG. 9 was prepared in the following manner: a reflective ITO electrode serving as a transparent anode 2 was formed on a glass substrate 1 beforehand, and a hole-injecting layer 3, a hole-transporting layer 4, an electron-blocking layer 5, a light-emitting layer 6, an electron-transporting layer 7, an electron-injecting layer 8, a cathode 9, and a capping layer 10 were vapor-deposited in this order on the ITO electrode.

[0120] Specifically, a glass substrate 1 on which an ITO film with a thickness of 50 nm, a reflective silver alloy film with a thickness of 100 nm, and an ITO film with a thickness of 5 nm were formed in this order was ultrasonically cleaned in isopropyl alcohol for 20 minutes, and then dried for 10 minutes on a hot plate heated to 250° C. After that, UV/ozone treatment was performed for 15 minutes. Then, the glass substrate with ITO was set inside a vacuum vapor deposition machine, and the pressure was reduced to 0.001 Pa or less.

[0121] Subsequently, an electron acceptor (Acceptor-1) having the structural formula below and a compound (HTM-1) having the structural formula below were vapor-deposited so as to coat the transparent anode 2 through binary vapor deposition at vapor deposition rates such that the ratio of the vapor deposition rate of Acceptor-1 to the vapor deposition rate of the compound (HTM-1) was 3:97, to thereby form the hole-injecting layer 3 with a thickness of 10 nm.

[0122] On this hole-injecting layer 3, the hole-transporting layer 4 (thickness: 140 nm) made of the compound (HTM-1) having the structural formula below was formed.

[0123] On this hole-transporting layer 4, the electron-blocking layer 5 (thickness: 5 nm) made of Compound (12) obtained in Example 1 was formed.

[0124] A compound (EMD-1) having the structural formula below and a compound (EMH-1) having the structural formula below were vapor-deposited on this electron-blocking layer 5 through binary vapor deposition at vapor deposition rates such that the ratio of the vapor deposition rate of the compound (EMD-1) to the vapor deposition rate of EMH-1 was 5:95, to thereby form the light-emitting layer 6 with a thickness of 20 nm.

[0125] A compound (ETM-1) having the structural formula below and a compound (ETM-2) having the structural formula below were vapor-deposited on this light-emitting layer 6 through binary vapor deposition at vapor deposition rates such that the ratio of the vapor deposition rate of the compound (ETM-1) to the vapor deposition rate of (ETM-2) was 50:50, to thereby form the electron-transporting layer 7 with a thickness of 30 nm.

[0126] On this electron-transporting layer 7, the electron-injecting layer 8 (thickness: 1 nm) made of lithium fluoride was formed.

[0127] On this electron-injecting layer 8, the cathode 9 (thickness: 12 nm) made of a magnesium-silver alloy was formed.

[0128] Finally, the capping layer 10 (thickness: 60 nm) made of a compound (CPL-1) having the structure below was formed.

[0129] Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the organic EL device prepared in Example 12 above.

##STR00011## ##STR00012## ##STR00013##

Example 13

[0130] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (14) obtained in Example 2. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 14

[0131] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (52) obtained in Example 3. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 15

[0132] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (7) obtained in Example 4. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 16

[0133] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (24) obtained in Example 5. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 17

[0134] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (26) obtained in Example 6. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 18

[0135] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (43) obtained in Example 7. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 19

[0136] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (61) obtained in Example 8. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Example 20

[0137] An organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with Compound (94) obtained in Example 9. Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

Comparative Example 1

[0138] For comparison, an organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with a compound (HTM-2) having the structural formula below (see Patent Literature 5, for example). Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

##STR00014##

Comparative Example 2

[0139] For comparison, an organic EL device was prepared in the same manner as in Example 12, except that Compound (12) obtained in Example 1 used as the material for the electron-blocking layer 5 was replaced with a compound (HTM-3) having the structural formula below (see Patent Literature 5, for example). Table 3 collectively shows the measurement results of light emission characteristics when a DC voltage was applied in the atmosphere at normal temperature to the prepared organic EL device in the same measurement condition as in Example 12.

##STR00015##

[0140] The device lifespan of each of the organic EL devices prepared in Examples and Comparative Examples was measured. The device lifespan was defined as follows: the organic EL device was driven by constant current to emit light at an initial luminance (the luminance when light emission started) of 1000 cd/m.sup.2, and the time taken for the luminance to decay to 950 cd/m.sup.2 (corresponding to 95% based on the initial luminance (100%): 95% decay) was determined and used as the device lifespan.

TABLE-US-00003 TABLE 3 (@10 mA/cm.sup.2) Luminous Power Device Electron- Voltage Luminance efficacy efficiency lifespan blocking layer [V] [cd/m.sup.2] [cd/A] [lm/W] 95% decay Ex. 12 Compound 12 3.42 1055 10.56 9.31 387 hrs. Ex. 13 Compound 14 3.38 1026 10.30 9.07 420 hrs. Ex. 14 Compound 52 3.41 958 9.58 8.44 349 hrs. Ex. 15 Compound 7 3.40 1014 10.14 8.52 791 hrs. Ex. 16 Compound 24 3.32 1125 11.27 10.14 633 hrs. Ex. 17 Compound 26 3.42 957 9.57 8.81 712 hrs. Ex. 18 Compound 43 3.48 851 8.52 7.50 410 hrs. Ex. 19 Compound 61 3.44 1108 11.11 9.84 407 hrs. Ex. 20 Compound 94 3.41 926 9.27 8.13 376 hrs. Com. Ex. 1 HTM-2 3.52 828 8.28 7.29 327 hrs. Com. Ex. 2 HTM-3 3.50 798 7.98 7.03 298 hrs.

[0141] The following can be seen from Table 3. When a current with a current density of 10 mA/cm.sup.2 was applied, the organic EL devices of Comparative Examples 1 and 2 had a luminous efficacy of 7.98 to 8.28 cd/A, and the organic EL devices of Example 12 to 20 had a luminous efficacy of 8.52 to 11.27 cd/A, which is higher efficacy. Moreover, while the organic EL devices of Comparative Examples 1 and 2 had power efficiencies of 7.03 to 7.29 lm/W, the organic EL devices of Example 12 to 20 had power efficiencies of 7.50 to 10.14 lm/W and therefore exhibited higher efficiency. Furthermore, the organic EL devices of Comparative Examples 1 and 2 had a device lifespan (95% decay) of 298 to 327 hours; in contrast, the organic EL devices of Example 12 to 20 had a device lifespan of 349 to 791 hours, that is known to be prolonged.

[0142] As is clear from the results described above, the organic EL devices each including the arylamine compound having a fluorenyl skeleton-containing heterocycle structure of the present invention, which has high hole mobility and excellent electron blockability, have higher luminous efficacy and a longer lifespan than conventional organic EL devices.

INDUSTRIAL APPLICABILITY

[0143] The organic EL device including the arylamine compound having a fluorenyl skeleton-containing heterocycle structure of the present invention has increased luminous efficacy and improved durability, and therefore, can be applied to a wide variety of uses such as home electric appliances and lighting equipment.

[0144] Moreover, the arylamine compound having a fluorenyl skeleton-containing heterocycle structure of the present invention can be applied not only to organic EL devices but also to electronic apparatuses in the fields of electrophotographic photoreceptors, image sensors, photoelectric transducers, solar cells, and the like.

LIST OF REFERENCE NUMERALS

[0145] 1 Glass substrate [0146] 2 Transparent anode [0147] 3 Hole-injecting layer [0148] 4 Hole-transporting layer [0149] 5 Electron-blocking layer [0150] 6 Light-emitting layer [0151] 7 Electron-transporting layer [0152] 8 Electron-injecting layer [0153] 9 Cathode [0154] 10 Capping layer