COMPOUND HAVING BENZOTRIAZOLE RING STRUCTURE AND ORGANIC ELECTROLUMINESCENCE ELEMENT

Abstract

An objective of the invention is to provide, as a material for highly efficient, highly durable organic EL devices, an organic compound having excellent properties, such as excellent electron injection capability and transportability, hole blocking capability, and high stability in a thin-film state, and also to provide a highly efficient, highly durable organic EL device by using this compound. The present invention has been achieved by focusing on the fact that a benzotriazole ring structure, which has electron affinity, contains nitrogen atoms having the ability to coordinate with a metal and also has excellent heat resistance, and by thus designing and chemically synthesizing various compounds having a benzotriazole ring structure and assessing the properties of various organic EL devices using those compounds, thereby finding out that organic EL devices having excellent properties can be achieved by using specifically-structured compounds having a benzotriazole ring structure.

Claims

1. A compound having a benzotriazole ring structure and being represented by general formula (a-1) as below: ##STR00032## (in the formula, R may be the same or different from one another, and each represents a group represented by structural formula (b-1) as below, a hydrogen atom, a deuterium atom, a fluorine atom, a chlorine atom, a cyano group, a nitro group, a trimethylsilyl group, a triphenylsilyl group, a diphenylphosphinyl group, a diphenylphosphine oxide group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, a substituted or unsubstituted fused polycyclic aromatic 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, or a cycloalkyloxy group having 5 to 10 carbon atoms and optionally having a substituent, wherein at least one of Rs is a group represented by the following structural formula (b-1)); ##STR00033## (in the formula, the broken line represents a bonding site, L.sub.1 represents a single bond, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group, L.sub.2 represents a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group, and n is an integer of 1 or 2, wherein L.sub.2 is a trivalent group when n is the integer 2).

2. The compound having a benzotriazole ring structure according to claim 1, represented by general formula (a-2) as below: ##STR00034## (in the formula, R has the same meaning as in the general formula (a-1)).

3. The compound having a benzotriazole ring structure according to claim 2, represented by general formula (a-3) as below: ##STR00035## (in the formula, R has the same meaning as in the general formula (a-1)).

4. The compound having a benzotriazole ring structure according to claim 2, represented by general formula (a-4) as below: ##STR00036## (in the formula, R has the same meaning as in the general formula (a-1)).

5. The compound having a benzotriazole ring structure according to claim 2, represented by general formula (a-5) as below: ##STR00037## (in the formula, R has the same meaning as in the general formula (a-1)).

6. The compound having a benzotriazole ring structure according to claim 5, represented by general formula (a-6) as below: ##STR00038## (in the formula, R has the same meaning as in the general formula (a-1)).

7. The compound having a benzotriazole ring structure according to claim 5, represented by general formula (a-7) as below: ##STR00039## (in the formula, R has the same meaning as in the general formula (a-1)).

8. The compound having a benzotriazole ring structure according to claim 1, wherein n in the structural formula (b-1) is the integer 1.

9. The compound having a benzotriazole ring structure according to claim 1, wherein L.sub.2 in the structural formula (b-1) is a substituted or unsubstituted aromatic hydrocarbon group.

10. An organic electroluminescence device comprising: a pair of electrodes; and at least one organic layer sandwiched between the electrodes, wherein the at least one organic layer is an organic layer containing the compound having a benzotriazole ring structure according to claim 1.

11. The organic electroluminescence device according to claim 10, wherein the organic layer containing the compound having a benzotriazole ring structure is an electron transport layer.

12. The organic electroluminescence device according to claim 10, wherein the organic layer containing the compound having a benzotriazole ring structure is a hole blocking layer.

13. The organic electroluminescence device according to claim 10, wherein the organic layer containing the compound having a benzotriazole ring structure is a light-emitting layer.

14. The organic electroluminescence device according to claim 10, wherein the organic layer containing the compound having a benzotriazole ring structure is an electron injection layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0078] FIG. 1 is a diagram illustrating structures of Compounds 1 to 18 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0079] FIG. 2 is a diagram illustrating structures of Compounds 19 to 33 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0080] FIG. 3 is a diagram illustrating structures of Compounds 34 to 54 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0081] FIG. 4 is a diagram illustrating structures of Compounds 55 to 68 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0082] FIG. 5 is a diagram illustrating structures of Compounds 69 to 82 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0083] FIG. 6 is a diagram illustrating structures of Compounds 83 to 97 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0084] FIG. 7 is a diagram illustrating structures of Compounds 98 to 114 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0085] FIG. 8 is a diagram illustrating structures of Compounds 115 to 130 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0086] FIG. 9 is a diagram illustrating structures of Compounds 131 to 146 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0087] FIG. 10 is a diagram illustrating structures of Compounds 147 to 162 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0088] FIG. 11 is a diagram illustrating structures of Compounds 163 to 179 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0089] FIG. 12 is a diagram illustrating structures of Compounds 180 to 193 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0090] FIG. 13 is a diagram illustrating structures of Compounds 194 to 207 as concrete examples of compounds having a benzotriazole ring structure represented by general formulas (a-1) to (a-7).

[0091] FIG. 14 is a diagram illustrating a configuration of an organic EL device for Examples 16 to 28 and Comparative Examples 1 and 2.

DESCRIPTION OF EMBODIMENTS

[0092] The compound having a benzotriazole ring structure of the present invention is a compound represented by one of the general formulas (a-1) to (a-7), but from the viewpoint of electron injection capability and transportability, a compound represented by the general formula (a-3), and more preferably a compound represented by the following general formula (a-3a) or general formula (a-3b), is preferable.

##STR00009##

[0093] (In the formula, R may be the same or different from one another, and each represents a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group, wherein the two Rs are never both hydrogen atoms.

[0094] L.sub.1 represents a single bond, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted fused polycyclic aromatic group, and

[0095] L.sub.2 represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted fused polycyclic aromatic group.)

##STR00010##

[0096] (In the formula, R may be the same or different from one another, and each represents a hydrogen atom, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted aromatic heterocyclic group, or a substituted or unsubstituted fused polycyclic aromatic group, wherein the two Rs are never both hydrogen atoms.

[0097] L.sub.1 represents a single bond, a substituted or unsubstituted aromatic hydrocarbon group, or a substituted or unsubstituted fused polycyclic aromatic group, and

[0098] L.sub.2 represents a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted fused polycyclic aromatic group.)

[0099] From the viewpoint of electron injection capability and transportability, it is preferable that L.sub.1 in the general formulas (a-3a) and (a-3b) is a single bond or a 1,4-naphthylene group, and L.sub.2 is a 1,4-phenylene group or a 4,4′-biphenylylene group.

[0100] FIGS. 1 to 13 illustrate concrete examples of preferred compounds among compounds having a benzotriazole ring structure represented by the general formulas (a-1) to (a-7) that may be suitably used for the organic EL device of the present invention. Note, however, that the compounds are not limited to the illustrated compounds.

[0101] The compounds having a benzotriazole ring structure of the present invention are novel compounds. These compounds can be synthesized according to a known method as described below, for example (see, for example, Patent Literatures 3 and 5).

##STR00011## ##STR00012##

[0102] The compound having a benzotriazole ring structure represented by one of general formulas (a-1) to (a-7) can be purified by such techniques as column chromatography purification, adsorption purification with silica gel, activated carbon, activated clay, etc., recrystallization or crystallization using a solvent, sublimation purification, or the like. Compound identification can be achieved by NMR analysis. Physical properties to be measured preferably include such values as the melting point, glass transition point (Tg), work function, or the like. The melting point serves as an index of vapor deposition characteristics. The glass transition point (Tg) serves as an index of stability in a thin-film state. The work function serves as an index of hole transportability and hole blocking capability.

[0103] The melting point and glass transition point (Tg) can be measured, for example, with a high-sensitivity differential scanning calorimeter (DSC3100SA from Bruker AXS) using a powder.

[0104] The work function can be found, for example, with an ionization potential measurement device (PYS-202 from Sumitomo Heavy Industries, Ltd.) by preparing a 100-nm thin film on an ITO substrate.

[0105] A structure of the organic EL device of the present invention may, for example, sequentially include, on a substrate, an anode, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, and a cathode. In other examples, an electron blocking layer may be provided between the hole transport layer and the light-emitting layer, or a hole blocking layer may be provided between the light-emitting layer and the electron transport layer. In such multilayer structures, a single organic layer may have functions of several layers; for example, a single organic layer may have functions of the hole injection layer and the hole transport layer, or functions of the electron injection layer and the electron transport layer. Further, it is possible to stack two or more organic layers having the same function; for example, the structure may include: two stacked hole transport layers; two stacked light-emitting layers; or two stacked electron transport layers.

[0106] For the anode in the organic EL device of the present invention, it is possible to use an electrode material having a large work function, such as ITO or gold. For the material for the hole injection layer in the organic EL device of the present invention, it is possible to use: a porphyrin compound typified by copper phthalocyanine; a starburst triphenylamine derivative; an arylamine compound including, in its molecule, two or more triphenylamine structures or carbazolyl structures which are linked by a single bond or a divalent group containing no hetero atom; an acceptor heterocyclic compound such as hexacyanoazatriphenylene; or a coating-type polymer material. These materials can form thin films by known methods, such as vapor deposition, spin coating, ink-jetting, etc.

[0107] For the material for the hole transport layer in the organic EL device of the present invention, it is possible to use a benzidine derivative, such as N,N′-diphenyl-N,N′-di(m-tolyl)-benzidine (abbreviated hereinbelow as “TPD”), N,N′-diphenyl-N,N′-di(a-naphthyl)-benzidine (abbreviated hereinbelow as “NPD”), N,N,N′,N′-tetrabiphenylylbenzidine, etc., or 1,1-bis[(di-4-tolylamino)phenyl]cyclohexane (abbreviated hereinbelow as “TAPC”), or an arylamine compound including, in its molecule, two or more triphenylamine structures or carbazolyl structures which are linked by a single bond or a divalent group containing no hetero atom.

[0108] These materials may each be formed into a film singly, or may be mixed with other materials and formed into a film, and each may be used as a single layer. It is possible to form a laminate structure constituted by layers each formed singly by the respective materials, or a laminate structure constituted by layers formed by mixing a plurality of materials, or a laminate structure constituted by layers each formed singly by the respective materials and layers formed by mixing a plurality of materials.

[0109] Further, for the hole injection-transport layer, it is possible to use a coating-type polymer material, such as poly(3,4-ethylenedioxythiophene) (abbreviated hereinbelow as “PEDOT”)/poly(styrene sulfonate) (abbreviated hereinbelow as “PSS”).

[0110] These materials can form thin films by known methods, such as vapor deposition, spin coating, ink-jetting, etc.

[0111] For the hole injection layer and the hole transport layer, it is possible to use: a material ordinarily used for such layers and p-doped with trisbromophenylamine hexachloroantimonate or a radialene derivative (see, for example, Patent Literature 6); or a polymer compound having, as a partial structure thereof, a benzidine derivative structure such as TPD.

[0112] For the material for the electron blocking layer in the organic EL device of the present invention, it is possible to use a compound having an electron blocking action, such as: a carbazole derivative, such as 4,4′,4″-tri(N-carbazolyl)triphenylamine (abbreviated hereinbelow as “TCTA”), 9,9-bis[4-(carbazol-9-yl)phenyl]fluorene, 1,3-bis(carbazol-9-yl)benzene (abbreviated hereinbelow as “mCP”), 2,2-bis(4-carbazol-9-ylphenyl)adamantane (abbreviated hereinbelow as “Ad-Cz”), etc.; or a compound containing a triarylamine structure and a triphenylsilyl group typified by 9-[4-(carbazol-9-yl)phenyl]-9-[4-(triphenylsilyl)phenyl]-9H-fluorene, etc.

[0113] These materials may each be formed into a film singly, or may be mixed with other materials and formed into a film, and each may be used as a single layer. It is possible to form a laminate structure constituted by layers each formed singly by the respective materials, or a laminate structure constituted by layers formed by mixing a plurality of materials, or a laminate structure constituted by layers each formed singly by the respective materials and layers formed by mixing a plurality of materials. These materials can form thin films by known methods, such as vapor deposition, spin coating, ink-jetting, etc.

[0114] For the material for the light-emitting layer in the organic EL device of the present invention, it is possible to use, other than the compound having a benzotriazole ring structure of the present invention, one of various metal complexes such as a metal complex of a quinolinol derivative, e.g., Alq.sub.3, an anthracene derivative, a bisstyrylbenzene derivative, a pyrene derivative, an oxazole derivative, a poly(para-phenylene vinylene) derivative, etc. The light-emitting layer may be constituted by a host material and a dopant material. For the host material, an anthracene derivative may preferably be used, and also, in addition to such light-emitting materials as the compound having a benzotriazole ring structure of the present invention, it is possible to use, for example, 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, a polydialkylfluorene derivative, etc. For the dopant material, it is possible to use quinacridone, coumarin, rubrene, perylene, a derivative of the above, a benzopyran derivative, a rhodamine derivative, an aminostyryl derivative, etc.

[0115] These materials may each be formed into a film singly, or may be mixed with other materials and formed into a film, and each may be used as a single layer. It is possible to form a laminate structure constituted by layers each formed singly by the respective materials, or a laminate structure constituted by layers formed by mixing a plurality of materials, or a laminate structure constituted by layers each formed singly by the respective materials and layers formed by mixing a plurality of materials.

[0116] It is also possible to use a phosphorescent substance for the light-emitting material. For the phosphorescent substance, it is possible to use a phosphorescent substance such as a metal complex of iridium, platinum, etc. Examples may include green phosphorescent substances such as Ir(ppy).sub.3 etc., blue phosphorescent substances such as Flrpic, FIr6, etc., and red phosphorescent substances such as Btp.sub.2Ir(acac) etc. As regards host materials, for the hole injecting/transporting host material, it is possible to use, for example, a carbazole derivative such as 4,4′-di(N-carbazolyl) biphenyl (abbreviated hereinbelow as “CBP”), TCTA, mCP, etc., as well as the compound having a benzotriazole ring structure of the present invention. For the electron-transporting host material, it is possible to use, for example, p-bis(triphenylsilyl)benzene (abbreviated hereinbelow as “UGH2”), 2,2′,2″-(1,3,5-phenylene)-tris(1-phenyl-1H-benzimidazole) (abbreviated hereinbelow as “TPBI”), etc.

[0117] To avoid concentration quenching, doping of the host material(s) with a phosphorescent light-emitting material is preferably performed by co-vapor deposition within a range of 1 to 30 wt. % with respect to the entire light-emitting layer.

[0118] Further, for the light-emitting material, it is possible to use a material emitting delayed fluorescence, e.g., PIC-TRZ, CC2TA, PXZ-TRZ, a CDCB derivative such as 4CzIPN, etc. (see, for example, Non-Patent Literature 3). These materials can form thin films by known methods, such as vapor deposition, spin coating, ink-jetting, etc.

[0119] For the material for the hole blocking layer in the organic EL device of the present invention, it is possible to use, other than the compound having a benzotriazole ring structure of the present invention, a compound having a hole blocking action, with examples including phenanthroline derivatives such as BCP, metal complexes of a quinolinol derivative such as BAlq, various rare-earth complexes, oxazole derivatives, triazole derivatives, triazine derivatives, etc. These materials may also serve as materials for the electron transport layer.

[0120] These materials may each be formed into a film singly, or may be mixed with other materials and formed into a film, and each may be used as a single layer. It is possible to form a laminate structure constituted by layers each formed singly by the respective materials, or a laminate structure constituted by layers formed by mixing a plurality of materials, or a laminate structure constituted by layers each formed singly by the respective materials and layers formed by mixing a plurality of materials. These materials can form thin films by known methods, such as vapor deposition, spin coating, ink-jetting, etc.

[0121] For the material for the electron transport layer in the organic EL device of the present invention, it is possible to use, other than the compound having a benzotriazole ring structure of the present invention, a metal complex of a quinolinol derivative such as Alq.sub.3, BAlq, etc., one of various metal complexes, a triazole derivative, a triazine derivative, an oxadiazole derivative, a pyridine derivative, a benzimidazole derivative, a thiadiazole derivative, an anthracene derivative, a carbodiimide derivative, a quinoxaline derivative, a pyridoindole derivative, a phenanthroline derivative, a silole derivative, etc.

[0122] These materials may each be formed into a film singly, or may be mixed with other materials and formed into a film, and each may be used as a single layer. It is possible to form a laminate structure constituted by layers each formed singly by the respective materials, or a laminate structure constituted by layers formed by mixing a plurality of materials, or a laminate structure constituted by layers each formed singly by the respective materials and layers formed by mixing a plurality of materials. These materials can form thin films by known methods, such as vapor deposition, spin coating, ink-jetting, etc.

[0123] For the material for the electron injection layer in the organic EL device of the present invention, it is possible to use, other than the compound having a benzotriazole ring structure of the present invention, an alkali metal salt such as lithium fluoride, cesium fluoride, etc., an alkaline-earth metal salt such as magnesium fluoride etc., a metal complex of a quinolinol derivative such as quinolinol lithium etc., a metal oxide such as aluminum oxide etc., or a metal such as ytterbium (Yb), samarium (Sm), calcium (Ca), strontium (Sr), cesium (Cs), etc. The electron injection layer may, however, be omitted by suitable selection of the electron transport layer and the cathode.

[0124] For the electron injection layer and the electron transport layer, it is possible to use a material ordinarily used for such layers and n-doped with a metal such as cesium etc.

[0125] For the cathode in the organic EL device of the present invention, an electrode material having a low work function, such as aluminum etc., or an alloy having an even lower work function, such as magnesium silver alloy, magnesium indium alloy, aluminum magnesium alloy, etc., may be used as the electrode material.

EXAMPLES

[0126] Embodiments of the present invention will be described in further detail below according to working examples. Note, however, that the present invention is not limited to the following examples so long as they do not go beyond the gist of the invention.

Example 1

Synthesis of 2-(4′-cyano-biphenyl-4-yl)-5-(9,9′-spirobi[9H]fluoren-2-yl)-2H-benzotriazole (Compound-2)

[0127] A reaction vessel was charged with 9.0 g of 2-(4-chloro-phenyl)-5-(9,9′-spirobi[9H]fluoren-2-yl)-2H-benzotriazole, 2.9 g of 4-cyano-phenylboronic acid, 0.5 g of tris(dibenzylideneacetone) dipalladium(0), 0.2 g of tricyclohexyl phosphine, and 10.5 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, ethyl acetate/H.sub.2O was added into the system, and the organic layer taken out by extraction and liquid separation was concentrated. The obtained concentrate was purified by column chromatography (adsorbent: silica gel; eluent: dichloromethane/n-heptane), to obtain 8.1 g of a yellow powder of 2-(4′-cyano-biphenyl-4-yl)-5-(9,9′-spirobi[9H]fluoren-2-yl)-2H-benzotriazole (Compound-2) (yield: 80%).

##STR00013##

[0128] The structure of the obtained yellow powder was identified by NMR.

[0129] The following 26 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0130] δ (ppm)=8.46 (2H), 7.97 (2H), 7.94 (1H), 7.90 (3H), 7.81-7.72 (7H), 7.59 (1H), 7.43 (1H), 7.42 (2H), 7.16 (3H), 7.07 (1H), 6.83 (2H), 6.79 (1H).

Example 2

Synthesis of 2-(4-cyano-[1,1′, 4′, 1″]terphenyl-4″-yl)-5,6-diphenyl-benzotriazole (Compound-40)

[0131] A reaction vessel was charged with 20.0 g of 2-(4-bromophenyl)-5,6-dichloro-benzotriazole, 18.7 g of 4′-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)biphenyl-4-carbonitrile, 210 mL of toluene, and 70 mL of ethanol, followed by an aqueous solution made by dissolving, in advance, 9.7 g of potassium carbonate in 70 mL of H.sub.2O, and was aerated with nitrogen gas for 30 minutes under ultrasonic irradiation. To the solution aerated with nitrogen gas was added 1.7 g of tetrakistriphenylphosphine palladium, and the mixture was stirred overnight while being heated to reflux. After stirring, the mixture was allowed to cool, and then, methanol and H.sub.2O were added, to perform dispersion washing and filtration and thereby obtain a crude product. The obtained crude product was subjected to dispersion washing with an acetone solvent, to obtain 21.8 g of a golden-yellow powder of 2-(4-cyano-[1,1′, 4′, 1″]terphenyl-4″-yl)-5,6-dichloro-benzotriazole (yield: 85%).

##STR00014##

[0132] The structure of the obtained golden-yellow powder was identified by NMR.

[0133] The following 14 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0134] δ (ppm)=8.46 (2H), 8.12 (2H), 7.87 (2H), 7.84-7.71 (8H).

[0135] Subsequently, 8.0 g of 2-(4-cyano-[1,1′, 4′, 1″]terphenyl-4″-yl)-5,6-dichloro-benzotriazole, 6.6 g of phenylboronic acid, 0.8 g of tris(dibenzylideneacetone)dipalladium(0), 1.0 g of tricyclohexylphosphine, and 23.1 g of tripotassium phosphate were charged, and were stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, H.sub.2O was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a dichlorobenzene solvent, to obtain 8.3 g of a white powder of 2-(4-cyano-[1,1′,4′,1″]terphenyl-4″-yl)-5,6-diphenyl-benzotriazole (Compound-40) (yield: 87%).

##STR00015##

[0136] The structure of the obtained white powder was identified by NMR.

[0137] The following 24 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0138] δ (ppm)=8.53 (2H), 8.00 (2H), 7.87 (2H), 7.79 (8H), 7.28-7.16 (10H).

Example 3

Synthesis of 2-(4-cyano-[1,1′, 4′, 1″]terphenyl-4″-yl)-5,6-di(naphthalen-1-yl)-benzotriazole (Compound-44)

[0139] A reaction vessel was charged with 5.0 g of 2-(4-cyano-[1, 1′, 4′, 1″]terphenyl-4″-yl)-5,6-dichloro-benzotriazole, 6.2 g of 1-naphthaleneboronic acid, 0.5 g of tris(dibenzylideneacetone)dipalladium(0), 0.6 g of tricyclohexylphosphine, and 14.4 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, H.sub.2O was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by crystallization with a dichlorobenzene/acetone mixed solvent, to obtain 4.6 g of a white powder of 2-(4-cyano-[1,1′, 4′, 1″]terphenyl-4″-yl)-5,6-di(naphthalen-1-yl)-benzotriazole (Compound-44) (yield: 65%).

##STR00016##

[0140] The structure of the obtained white powder was identified by NMR.

[0141] The following 28 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0142] δ (ppm)=8.58 (2H), 8.14 (2H), 7.94-7.73 (13H), 7.60 (3H), 7.46 (2H), 7.28 (3H), 7.11 (1H), 7.01 (2H).

Example 4

Synthesis of 2-(4″-cyano-[1, 1 ‘; 4’, 1″]terphenyl-4-yl)-5-(phenanthren-9-yl)-6-phenyl-2H-benzotriazole (Compound-48)

[0143] A reaction vessel was charged with 13.1 g of 5-chloro-2-(4″-cyano-[1, 1 ‘; 4’, 1″]terphenyl-4-yl)-6-phenyl-2H-benzotriazole, 12.6 g of 9-phenanthreneboronic acid, 1.5 g of tris(dibenzylideneacetone)dipalladium(0), 1.5 g of tricyclohexylphosphine, and 23.0 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a chlorobenzene solvent, to obtain 6.6 g of a white powder of 2-(4″-cyano-[1,1′; 4′, 1]terphenyl-4-yl)-5-(phenanthren-9-yl)-6-phenyl-2H-benzotriazole (Compound-48) (yield: 39%).

##STR00017##

[0144] The structure of the obtained white powder was identified by NMR.

[0145] The following 28 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0146] δ (ppm)=8.68 (2H), 8.56 (2H), 8.10 (2H), 7.89 (2H), 7.84 (3H), 7.77 (6H), 7.70 (1H), 7.67 (2H), 7.59 (2H), 7.42 (1H), 7.23 (2H), 7.00 (3H).

Example 5

Synthesis of 2-[4-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-phenyl]-5-(phenanthren-9-yl)-2H-benzotriazole (Compound-78)

[0147] A reaction vessel was charged with 5.6 g of 2-(4-chloro-phenyl)-5-(phenanthren-9-yl)-2H-benzotriazole, 6.2 g of 4′-{4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-naphthalen-1-yl}-biphenyl-4-carbonitrile, 0.4 g of tris(dibenzylideneacetone)dipalladium(0), 0.4 g of tricyclohexylphosphine, and 5.9 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by crystallization with a chlorobenzene/acetone mixed solvent, to obtain 3.3 g of a pale-yellow powder of 2-[4-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-phenyl]-5-(phenanthren-9-yl)-2H-benzotriazole (Compound-78) (yield: 35%).

##STR00018##

[0148] The structure of the obtained pale-yellow powder was identified by NMR.

[0149] The following 30 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0150] δ (ppm)=8.86 (1H), 8.80 (1H), 8.60 (2H), 8.18 (1H), 8.10 (2H), 8.08 (1H), 8.00 (1H), 7.97 (1H), 7.88-7.65 (15H), 7.61 (3H), 7.55 (2H).

Example 6

Synthesis of 2-(4-(phenanthren-9-yl)-phenyl)-5-(4′-cyano-biphenyl-4-yl)-6-phenyl-benzotriazole (Compound-104)

[0151] A reaction vessel was charged with 26.0 g of 2-(4-bromophenyl)-5-chloro-6-phenyl-benzotriazole, 15.8 g of 9-phenanthreneboronic acid, 180 mL of toluene, and 45 mL of ethanol, followed by an aqueous solution made by dissolving, in advance, 11.2 g of potassium carbonate in 40 mL of H.sub.2O, and was aerated with nitrogen gas for 30 minutes under ultrasonic irradiation. To the solution aerated with nitrogen gas was added 1.6 g of tetrakistriphenylphosphine palladium, and the mixture was stirred overnight while being heated to reflux. After stirring, the mixture was allowed to cool, and then, ethyl acetate and H.sub.2O were added, and the organic layer was taken out by extraction and liquid separation, and a crude product was obtained by concentration under reduced pressure. The obtained crude product was purified by crystallization with an acetone/methanol mixed solvent, to obtain 28.0 g of a yellow powder of 2-(4-(phenanthren-9-yl)-phenyl)-5-chloro-6-phenyl-benzotriazole (yield: 86%).

##STR00019##

[0152] The structure of the obtained yellow powder was identified by NMR.

[0153] The following 20 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0154] δ (ppm)=8.84 (1H), 8.78 (1H), 8.54 (2H), 8.15 (1H), 7.97 (3H), 7.84-7.45 (12H).

[0155] Subsequently, 14.0 g of 2-(4-(phenanthren-9-yl)-phenyl)-5-chloro-6-phenyl-benzotriazole, 9.3 g of 4′-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)biphenyl-4-carbonitrile, 0.8 g of tris(dibenzylideneacetone)dipalladium(0), 0.8 g of tricyclohexylphosphine, and 12.3 g of tripotassium phosphate were charged, and were stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and the precipitated solid was filtered, to obtain a crude product. The obtained crude product was purified by recrystallization with a monochlorobenzene solvent, to obtain 11.8 g of a white powder of 2-(4-(phenanthren-9-yl)-phenyl)-5-(4′-cyano-biphenyl-4-yl)-6-phenyl-benzotriazole (Compound-104) (yield: 65%).

##STR00020##

[0156] The structure of the obtained white powder was identified by NMR.

[0157] The following 28 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0158] δ (ppm)=8.85 (1H), 8.78 (1H), 8.58 (2H), 8.07 (2H), 7.98 (2H), 7.87-7.64 (9H), 7.61 (1H), 7.53 (2H), 7.40-7.23 (8H).

Example 7

Synthesis of 2-(4′″-cyano-[1,1′; 4′, 1″; 4″, 1′″]quaterphenyl-4-yl)-5-(phenanthren-9-yl)-2H-benzotriazole (Compound-141)

[0159] A reaction vessel was charged with 10.0 g of 2-(4-chloro-phenyl)-5-(phenanthren-9-yl)-2H-benzotriazole, 9.9 g of 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-[1,1′;4′,1″]terphenyl-4″-carbonitrile, 0.7 g of tris(dibenzylideneacetone)dipalladium(0), 0.7 g of tricyclohexylphosphine, and 10.5 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a 1,2-dichlorobenzene solvent, to obtain 10.4 g of a yellow powder of 2-(4′″-cyano-[1,1′; 4′, 1″; 4″, 1′″]quaterphenyl-4-yl)-5-(phenanthren-9-yl)-2H-benzotriazole (Compound-141) (yield: 67%).

##STR00021##

[0160] The structure of the obtained yellow powder was identified by NMR.

[0161] The following 30 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0162] δ (ppm)=8.82 (1H), 8.77 (1H), 8.53 (2H), 8.13 (1H), 8.07 (1H), 7.95 (2H), 7.88 (2H), 7.81 (7H), 7.77 (5H), 7.75-7.60 (7H), 7.57 (1H).

Example 8

Synthesis of 2-[4-{4-(4-cyano-phenyl)-naphthalen-1-yl}-phenyl]-5-(9,9′-spirobi[9H]fluoren-2-yl)-2H-benzotriazole (Compound-155)

[0163] A reaction vessel was charged with 9.0 g of 2-(4-chloro-phenyl)-5-(9,9′-spirobi[9H]fluoren-2-yl)-2H-benzotriazole, 6.5 g of 4-{4-(4,4, 5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-naphthalen-1-yl}-phenyl-carbonitrile, 0.3 g of tris(dibenzylideneacetone)dipalladium(0), 0.2 g of tricyclohexylphosphine, and 7.0 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, ethyl acetate/H.sub.2O was added into the system, and the organic layer taken out by extraction and liquid separation was concentrated. The obtained crude product was purified by recrystallization with an acetone solvent, to obtain 7.6 g of a white powder of 2-[4-{4-(4-cyano-phenyl)-naphthalen-1-yl}-phenyl]-5-(9,9′-spirobi[9H]fluoren-2-yl)-2H-benzotriazole (Compound-155) (yield: 62%).

##STR00022##

[0164] The structure of the obtained white powder was identified by NMR.

[0165] The following 32 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0166] δ (ppm)=8.50 (2H), 8.03 (1H), 8.00 (1H), 7.98 (1H), 7.91 (5H), 7.85 (2H), 7.80-7.65 (5H), 7.63-7.38 (8H), 7.17 (3H), 7.09 (1H), 6.84 (2H), 6.80 (1H).

Example 9

Synthesis of 5, 6-diphenyl-2-[4-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-phenyl]-2H-benzotriazole (Compound-164)

[0167] A reaction vessel was charged with 12.0 g of 5,6-dichloro-2-[4-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-phenyl]-2H-benzotriazole, 7.7 g of phenylboronic acid, 1.0 g of tris(dibenzylideneacetone)dipalladium(0), 1.2 g of tricyclohexylphosphine, and 26.9 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, H.sub.2O was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a chlorobenzene solvent, to obtain 8.2 g of a white powder of 5,6-diphenyl-2-[4-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-phenyl]-2H-benzotriazole (Compound-164) (yield: 60%).

##STR00023##

[0168] The structure of the obtained white powder was identified by NMR.

[0169] The following 30 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0170] δ (ppm)=8.55 (2H), 8.04 (2H), 8.00 (2H), 7.80 (4H), 7.77 (4H), 7.69 (2H), 7.57 (2H), 7.52 (2H), 7.29-7.16 (10H).

Example 10

Synthesis of 5-{4-(4-cyano-phenyl)-naphthalen-1-yl}-2-{4-(phenanthren-9-yl)-phenyl}-2H-benzotriazole (Compound-172)

[0171] A reaction vessel was charged with 11.0 g of 5-chloro-2-{4-(phenanthren-9-yl)-phenyl}-2H-benzotriazole, 10.1 g of 4-{4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-naphthalen-1-yl}-phenyl-carbonitrile, 0.7 g of tris(dibenzylideneacetone)dipalladium(0), 0.8 g of tricyclohexylphosphine, and 11.5 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a toluene solvent, to obtain 10.5 g of a pale-yellow powder of 5-{4-(4-cyano-phenyl)-naphthalen-1-yl}-2-{4-(phenanthren-9-yl)-phenyl}-2H-benzotriazole (Compound-172) (yield: 71%).

##STR00024##

[0172] The structure of the obtained pale-yellow powder was identified by NMR.

[0173] The following 26 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0174] δ (ppm)=8.82 (1H), 8.80 (1H), 8.57 (2H), 8.12 (1H), 8.11 (1H), 8.04 (1H), 7.98 (1H), 7.94 (1H), 7.88 (1H), 7.84 (2H), 7.79 (2H), 7.78 (1H), 7.74-7.56 (8H), 7.53 (1H), 7.51 (1H), 7.50 (1H).

Example 11

Synthesis of 5-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-2-{4-(phenanthren-9-yl)-phenyl}-2H-benzotriazole (Compound-184)

[0175] A reaction vessel was charged with 10.0 g of 5-chloro-2-{4-(phenanthren-9-yl)-phenyl}-2H-benzotriazole, 11.2 g of 4′-{4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-naphthalen-1-yl}-biphenyl-4-carbonitrile, 0.7 g of tris(dibenzylideneacetone)dipalladium(0), 0.7 g of tricyclohexylphosphine, and 10.5 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a chlorobenzene solvent, to obtain 4.1 g of a pale-yellow powder of 5-{4-(4′-cyano-biphenyl-4-yl)-naphthalen-1-yl}-2-{4-(phenanthren-9-yl)-phenyl}-2H-benzotriazole (Compound-184) (yield: 25%).

##STR00025##

[0176] The structure of the obtained pale-yellow powder was identified by NMR.

[0177] The following 30 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0178] δ (ppm)=8.82 (1H), 8.76 (1H), 8.57 (2H), 8.13 (1H), 8.10 (1H), 8.05 (2H), 7.98 (1H), 7.94 (1H), 7.84-7.75 (9H), 7.74-7.54 (9H), 7.51 (2H).

Example 12

Synthesis of 5-(4″-cyano-[1,1′; 4′, 1″]terphenyl-4-yl)-2-{4-(phenanthren-9-yl)-phenyl}-6-phenyl-2H-benzotriazole (Compound-189)

[0179] A reaction vessel was charged with 13.0 g of 5-chloro-2-{4-(phenanthren-9-yl)-phenyl}-6-phenyl-2H-benzotriazole, 8.6 g of 4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-[1, 1′; 4′, 1″]terphenyl-4″-carbonitrile, 0.7 g of tris(dibenzylideneacetone)dipalladium(0), 0.8 g of tricyclohexylphosphine, and 11.5 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a chlorobenzene solvent, to obtain 10.0 g of a white powder of 5-(4″-cyano-[1,1′; 4′, 1″]terphenyl-4-yl)-2-{4-(phenanthren-9-yl)-phenyl}-6-phenyl-2H-benzotriazole (Compound-189) (yield: 53%).

##STR00026##

[0180] The structure of the obtained white powder was identified by NMR.

[0181] The following 32 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0182] δ (ppm)=8.85 (1H), 8.78 (1H), 8.58 (2H), 8.07 (2H), 7.99 (2H), 7.85-7.61 (14H), 7.58 (2H), 7.32 (8H).

Example 13

Synthesis of 5-(4′-cyano-biphenyl-4-yl)-6-phenyl-2-(4′-pyridine-3-yl-biphenyl-4-yl)-2H-benzotriazole (Compound-201)

[0183] A reaction vessel was charged with 12.0 g of 5-chloro-6-phenyl-2-(4′-pyridine-3-yl-biphenyl-4-yl)-2H-benzotriazole, 8.4 g of 4′-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)biphenyl-4-carbonitrile, 0.7 g of tris(dibenzylideneacetone)dipalladium(0), 0.7 g of tricyclohexylphosphine, and 11.1 g of tripotassium phosphate, and the mixture was stirred under reflux overnight in a mixed solvent of 1,4-dioxane and H.sub.2O. After the mixture was allowed to cool, methanol was added into the system, and a crude product was obtained by dispersion washing and filtration. The obtained crude product was purified by recrystallization with a chlorobenzene solvent, to obtain 6.4 g of a white powder of 5-(4′-cyano-biphenyl-4-yl)-6-phenyl-2-(4′-pyridine-3-yl-biphenyl-4-yl)-2H-benzotriazole (Compound-201) (yield: 41%).

##STR00027##

[0184] The structure of the obtained white powder was identified by NMR.

[0185] The following 27 hydrogen signals were detected with .sup.1H-NMR (CDCl.sub.3).

[0186] δ (ppm)=8.46 (1H), 8.66 (1H), 8.53 (2H), 8.04 (2H), 7.98 (1H), 7.89 (2H), 7.84 (2H), 7.75 (6H), 7.52 (2H), 7.44 (1H), 7.37-7.22 (7H).

Example 14

[0187] Using a high-sensitivity differential scanning calorimeter (DSC3100SA from Bruker AXS), the melting point and the glass transition point were measured for each of the compounds having a benzotriazole ring structure synthesized in Examples 1 to 13. The measurement results are collectively shown in Table 1.

TABLE-US-00001 TABLE 1 Glass Melting transition point point Compound of Example 1 311° C. 151° C. Compound of Example 2 307° C. — Compound of Example 3 326° C. — Compound of Example 4 306° C. 139° C. Compound of Example 5 257° C. 117° C. Compound of Example 6 303° C. 137° C. Compound of Example 7 336° C. — Compound of Example 8 312° C. 167° C. Compound of Example 9 302° C. 118° C. Compound of Example 10 — 121° C. Compound of Example 11 — 121° C. Compound of Example 12 329° C. 141° C. Compound of Example 13 283° C. 110° C.

[0188] The results show that the compounds having a benzotriazole ring structure synthesized in Examples 1 to 13 each have a glass transition point of 98° C. or higher, thus indicating that they are stable in a thin-film state.

Example 15

[0189] A 100-nm-thick vapor deposition film was formed on an ITO substrate by using each of the compounds having a benzotriazole ring structure synthesized respectively in Examples 1 to 13, and the work function was measured using an ionization potential measurement device (PYS-202 from Sumitomo Heavy Industries, Ltd.). The measurement results are collectively shown in Table 2.

TABLE-US-00002 TABLE 2 Work function Compound of Example 1 6.41 eV Compound of Example 2 6.51 eV Compound of Example 3 6.42 eV Compound of Example 4 6.44 eV Compound of Example 5 6.41 eV Compound of Example 6 6.51 eV Compound of Example 7 6.34 eV Compound of Example 8 6.41 eV Compound of Example 9 6.40 eV Compound of Example 10 6.46 eV Compound of Example 11 6.42 eV Compound of Example 12 6.43 eV Compound of Example 13 6.62 eV

[0190] The results show that the compounds having a benzotriazole ring structure synthesized in Examples 1 to 13 have a greater work function than 5.5 eV, the work function of typical hole-transporting materials such as NPD, TPD, etc., and thus have high hole blocking capability.

Example 16

[0191] As illustrated in FIG. 14, an organic EL device was prepared by vapor-depositing a hole injection layer 3, a hole transport layer 4, a light-emitting layer 5, a hole blocking layer 6, an electron transport layer 7, an electron injection layer 8, and a cathode (aluminum electrode) 9 in this order onto a glass substrate 1 having formed thereon an ITO electrode as a transparent anode 2 in advance.

[0192] More specifically, a glass substrate 1 having formed thereon a 50-nm-thick ITO film as a transparent anode 2 was subjected to ultrasonic cleaning in isopropyl alcohol for 20 minutes, and then dried for 10 minutes on a hot plate heated to 200° C. Then, after UV ozone treatment for 15 minutes, the glass substrate having the ITO was mounted to a vacuum vapor deposition apparatus, in which the pressure was reduced to 0.001 Pa or lower. Next, a hole injection layer 3 was formed as the film of 10 nm thickness so as to cover the transparent anode 2, by performing binary vapor deposition of an electron acceptor (Acceptor-1) having the following structural formula and a compound (HTM-1) having the following structural formula at a rate at which the vapor deposition rate ratio between Acceptor-1 and HTM-1 was 3:97.

[0193] On this hole injection layer 3, the compound (HTM-1) having the following structural formula was formed as a hole transport layer 4 having a film thickness of 60 nm.

[0194] On this hole transport layer 4, a light-emitting layer 5 was formed so that the film thickness was 20 nm, by performing binary vapor deposition of a compound (EMD-1) having the following structural formula and a compound (EMH-1) having the following structural formula at a rate at which the vapor deposition rate ratio between EMD-1 and EMH-1 was 5:95.

[0195] On this light-emitting layer 5, a hole blocking layer-cum-electron transport layer 6, 7 was formed by performing binary vapor deposition of the compound of Example 1 (Compound-2) and a compound (ETM-1) having the following structural formula at a rate at which the vapor deposition rate ratio between Compound-2 and ETM-1 was 50:50, to the film thickness of 30 nm.

[0196] On this hole blocking layer-cum-electron transport layer 6, 7, lithium fluoride was formed as an electron injection layer 8 having a film thickness of 1 nm.

[0197] Finally, on this electron injection layer 8, a cathode 9 was formed by vapor-depositing aluminum to a thickness of 100 nm.

[0198] Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

##STR00028## ##STR00029##

Example 17

[0199] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-40) of Example 2 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-40 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 18

[0200] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-44) of Example 3 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-44 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 19

[0201] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-48) of Example 4 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-48 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 20

[0202] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-78) of Example 5 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-78 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 21

[0203] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-104) of Example 6 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-104 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 22

[0204] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-141) of Example 7 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-141 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 23

[0205] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-155) of Example 8 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-155 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 24

[0206] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-164) of Example 9 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-164 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 25

[0207] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-172) of Example 10 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-172 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 26

[0208] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-184) of Example 11 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-184 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 27

[0209] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-189) of Example 12 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-189 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Example 28

[0210] An organic EL device was produced according to the same conditions in Example 16, except that, the compound (Compound-201) of Example 13 was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between Compound-201 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

Comparative Example 1

[0211] For comparison, an organic EL device was produced according to the same conditions in Example 16, except that, a compound (ETM-2) having the following structural formula (see, for example, Patent Literature 7) was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between ETM-2 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

##STR00030##

Comparative Example 2

[0212] For comparison, an organic EL device was produced according to the same conditions in Example 16, except that, a compound (ETM-3) having the following structural formula (see, for example, Patent Literature 8) was used instead of the compound (Compound-2) of Example 1 as the material for the hole blocking layer-cum-electron transport layer 6, 7, and binary vapor deposition was performed at a vapor deposition rate at which the vapor deposition rate ratio between ETM-3 and ETM-1 was 50:50. Properties of the produced organic EL device were measured in the atmosphere at atmospheric temperature. Measurement results of light emission properties when a direct-current voltage was applied to the produced organic EL device are collectively shown in Table 3.

##STR00031##

[0213] Device life was measured using the organic EL devices produced in Examples 16 to 28 and Comparative Examples 1 and 2. The results are collectively shown in Table 3. Device life was measured as following, constant current driving was performed with the light emission luminance at the start of light emission (i.e., initial luminance) being 2000 cd/m.sup.2, and then the time for the light emission luminance attenuating to 1900 cd/m.sup.2 (95% attenuation: the equivalent of 95% of the initial luminance, that considering to be 100%) was measured.

TABLE-US-00003 TABLE 3 Luminous Power Voltage Luminance efficiency efficiency Hole blocking [V] [cd/m2] [cd/A] [lm/W] Device life, layer-cum-electron (@ 10 (@ 10 (@ 10 (@ 10 95% transport layer mA/cm.sup.2) mA/cm.sup.2) mA/cm.sup.2) mA/cm.sup.2) attenuation Example 16 Compound-2/  3.51 883 8.84 7.93 365 hours ETM-1 Example 17 Compound-40/  3.67 863 8.63 7.40 305 hours ETM-1 Example 18 Compound-44/  3.68 884 8.84 7.56 374 hours ETM-1 Example 19 Compound-48/  3.71 883 8.85 7.51 286 hours ETM-1 Example 20 Compound-78/  3.58 905 9.05 7.95 326 hours ETM-1 Example 21 Compound-104/ 3.58 897 8.97 7.88 262 hours ETM-1 Example 22 Compound-104/ 3.50 877 8.78 7.89 263 hours ETM-1 Example 23 Compound-104/ 3.54 887 8.87 7.89 373 hours ETM-1 Example 24 Compound-104/ 3.52 870 8.70 7.77 279 hours ETM-1 Example 25 Compound-104/ 3.55 909 9.10 8.05 389 hours ETM-1 Example 26 Compound-104/ 3.43 880 8.81 8.08 385 hours ETM-1 Example 27 Compound-104/ 3.50 868 8.69 7.82 344 hours ETM-1 Example 28 Compound-104/ 3.55 834 8.34 7.39 405 hours ETM-1 Comparative ETM-2/ETM-1 3.82 805 8.05 6.62 165 hours Example 1  Comparative ETM-3/ETM-1 4.01 659 6.59 5.16 203 hours Example 2 

[0214] As shown in Table 3, when a current having a current density of 10 mA/cm.sup.2 was passed, the drive voltage was 3.82 to 4.01 V for the organic EL devices of Comparative Examples 1 and 2 using compounds ETM-2 and ETM-3 having the structural formulas shown above, whereas the organic EL devices of Examples 16 to 28 had a reduced voltage of 3.43 to 3.71 V. Further, while the organic EL devices of Comparative Examples 1 and 2 had a luminous efficiency of 6.59 to 8.05 cd/A, the organic EL devices of Examples 16 to 28 had improved luminous efficiency of 8.34 to 9.10 cd/A. Furthermore, while the organic EL devices of Comparative Examples 1 and 2 had a power efficiency of 5.16 to 6.62 lm/W, the organic EL devices of Examples 16 to 28 had significantly improved power efficiency of 7.39 to 8.08 lm/W. Particularly, while the organic EL devices of Comparative Examples 1 and 2 had a device life (95% attenuation) of 165 to 203 hours, the organic EL devices of Examples 16 to 28 had a significantly prolonged lifetime of 262 to 405 hours.

[0215] As described above, the organic EL devices according to the present invention excelled in luminous efficiency and power efficiency, compared to devices using compounds ETM-2 and ETM-3 having the structural formulas shown above, and it could achieve organic EL devices with a long lifetime.

INDUSTRIAL APPLICABILITY

[0216] Compounds having a specific benzotriazole ring structure according to the present invention have good electron injection capability and excellent hole blocking capability and are stable in a thin film state and are thus excellent for organic EL devices. By producing organic EL devices using these compounds, high efficiency can be achieved, driving voltage can be reduced, and durability can be improved also. For example, application can be expanded to home electrical appliances and lightings.