JP5898148B2 - Organic electroluminescence device - Google Patents

Description

  The present invention relates to an organic electroluminescence element, a display device, and a lighting device.

  As a self-luminous element, organic electroluminescence that emits light by current flowing through the element (hereinafter also referred to as an organic EL element) is known. An organic EL device has a structure in which a light-emitting layer containing a light-emitting compound is sandwiched between a cathode and an anode, and excitons (excitons) are generated by injecting electrons and holes into the light-emitting layer and recombining them. The device emits light by utilizing the emission of light (fluorescence / phosphorescence) when the exciton is deactivated, and can emit light at a voltage of several volts to several tens of volts. Since organic EL elements are self-luminous, they have a wide viewing angle, high visibility, and are thin film-type completely solid elements. In recent years, organic EL elements have attracted attention from the viewpoint of space saving and portability. It is used in organic EL display devices such as televisions and mobile phones that display a plurality of image information.

  FIG. 6 is a cross-sectional view showing one pixel of a conventional organic EL element. In the conventional organic EL element, each pixel as described above is arranged in a matrix, and each pixel includes an anode 202 formed on a glass substrate 201 and a single layer of a thin organic compound as shown in FIG. Alternatively, a structure in which a plurality of organic layers (in FIG. 6, the hole-transporting layer 206, the light-emitting layer 207, and the electron-transporting layer 208 are equivalent) and the cathode 204 are sequentially stacked.

  A driving element 205 (TFT element or the like) is formed on the glass substrate 201 at the intersection of the matrix. Here, the anode 202 is made of a transparent conductive material such as indium oxide (ITO), and the cathode 204 is made of a metal material such as aluminum.

  A conventional organic EL element as shown in FIG. 6 injects holes from the anode 202 by applying a voltage between the anode 202 and the cathode 204 in the pixels arranged in a matrix, and the hole transport layer 206. In the meantime, electrons are injected from the cathode 204 and transported to the light emitting layer 207 through the electron transport layer 208, and in the light emitting layer 207 or at the interface with the adjacent layer, holes and electrons are transported. Are combined to emit light, and the emitted light is taken out from the transparent substrate 201 side through the anode 202 to perform display (also referred to as bottom emission).

  In this case, as long as the light emitted from the transparent substrate 201 side is taken out, even if the ratio occupied by the drive element 205 is reduced, the light emitted from the drive element 205 portion is blocked, so that the light emission efficiency is lowered.

  As a countermeasure, it has been considered to extract light emission from the cathode 204 side. At this time, as the cathode 204, a material having good light transmission and good electron injection efficiency is required, and the use of a structure in which a thin metal film and ITO are laminated is studied (for example, Patent Document 1). reference.).

  However, when producing an organic EL element having such a structure (also referred to as a top emission type organic EL element) different from conventional organic EL elements, high energy is applied to the organic thin film layer when forming the transparent electrode. As a result, the organic layer was damaged, causing a number of inconveniences such as reduction in luminous efficiency, generation of dark spots due to local heat generation, and shortening of the device life.

JP 2001-43980 A

  An object of the present invention is to provide an organic electroluminescence element exhibiting high luminous efficiency, a long emission lifetime, and reduced light emission defects, a display device having the organic electroluminescence element, and an illumination device.

The above object of the present invention is achieved by the following configurations 1 to 41 (first to 41st aspects), and specifically according to the present invention,
In the organic electroluminescent element in which the first electrode, the constituent layer including at least the light emitting layer and the electron transport layer, and the second electrode are stacked in this order on the substrate, and the second electrode side extracts light emission.
The first electrode is made of aluminum;
A compound in which at least one layer of the electron transport layer is represented by the following general formula (A) (excluding the case of constituting a ligand of a metal complex. The following compounds (47), (50) and (108) are also excluded ) . An organic electroluminescence device comprising at least one of the above is provided.

[Wherein, X ₁ represents a nitrogen atom, and X _{2 to} X ₈ each represents a carbon atom. R _{2 to} R ₈ bonded to the carbon atoms of X _{2 to} X ₈ each represent a hydrogen atom or a substituent, and when there are a plurality of the substituents, they may be the same or different. R ₁ bonded to the nitrogen atom of X ₁ represents an unshared electron pair. R ₉ represents a hydrogen atom or a substituent. ]

(First aspect)
In the organic electroluminescence device in which the first electrode, the constituent layer including at least the light emitting layer, and the second electrode are stacked in this order on the substrate, and light is extracted from the second electrode side.
At least one of the constituent layers contains at least one compound represented by the following general formula (A), an organic electroluminescence element.

[Wherein, X _{1 to} X ₈ each represent a carbon atom or a nitrogen atom, and at least one is a nitrogen atom. When any of X _{1 to} X ₈ is a carbon atom, R _{1 to} R ₈ bonded to the carbon atom each represent a hydrogen atom or a substituent, and when there are a plurality of the substituents, they are the same or different It may be. When any of X _{1 to} X ₈ is a nitrogen atom, R _{1 to} R ₈ bonded to the nitrogen atom each represent an unshared electron pair. R ₉ represents a hydrogen atom or a substituent. ]
(Second aspect)
The organic electroluminescence device, wherein the compound represented by the general formula (A) is a compound represented by the following general formula (1).

[Wherein, Z ₁ represents an aromatic heterocyclic ring, Z ₂ represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring, and Z ₃ represents a divalent linking group or a simple bond. R ₁₀₁ represents a hydrogen atom or a substituent. ]
(Third aspect)
The organic electroluminescent element according to the second aspect, wherein Z _{1 of the} compound represented by the general formula (1) is a 6-membered ring.

(Fourth aspect)
The organic electroluminescence device according to the second or third aspect, wherein Z _{2 of the} compound represented by the general formula (1) is a 6-membered ring.

(5th aspect)
The organic electroluminescent element according to any one of the second to fourth aspects, wherein Z _{3 of the} compound represented by the general formula (1) is a bond.

(Sixth aspect)
The organic electroluminescent element according to any one of the second to fifth aspects, wherein the compound represented by the general formula (1) has a molecular weight of 450 or more.

(Seventh aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-1), and the organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{501 to} R ₅₀₇ each independently represents a hydrogen atom or a substituent. ]
(Eighth aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-2), The organic electroluminescent element according to any one of the second to sixth aspects.

[Wherein, R _{511 to} R ₅₁₇ each independently represents a hydrogen atom or a substituent. ]
(Ninth aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-3). The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{521 to} R ₅₂₇ each independently represents a hydrogen atom or a substituent. ]
(Tenth aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-4), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{531 to} R ₅₃₇ each independently represents a hydrogen atom or a substituent. ]
(Eleventh aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-5), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{541 to} R ₅₄₈ each independently represents a hydrogen atom or a substituent. ]
(Twelfth aspect)
The organic electroluminescent element according to any one of the second to sixth aspects, wherein the compound represented by the general formula (1) is represented by the following general formula (1-6).

[Wherein, R _{551 to} R ₅₅₈ each independently represents a hydrogen atom or a substituent. ]
(13th aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-7), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{561 to} R ₅₆₇ each independently represents a hydrogen atom or a substituent. ]
(14th aspect)
The organic electroluminescent element according to any one of the second to sixth aspects, wherein the compound represented by the general formula (1) is represented by the following general formula (1-8).

[Wherein, R _{571 to} R ₅₇₇ each independently represents a hydrogen atom or a substituent. ]
(15th aspect)
The compound represented by the general formula (1) is represented by the following general formula (1-9), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R represents a hydrogen atom or a substituent. The plurality of R may be the same or different. ]
(Sixteenth aspect)
The organic electroluminescent element according to any one of the second to sixth aspects, wherein the compound represented by the general formula (1) is represented by the following general formula (1-10).

[Wherein, R represents a hydrogen atom or a substituent. The plurality of R may be the same or different. ]
(17th aspect)
The compound represented by the general formula (1) has at least one group represented by any one of the following general formulas (2-1) to (2-8). The organic electroluminescent element according to any one of the aspects.

[In the formula, R _{502 to} R ₅₀₇ , R _{512 to} R ₅₁₇ , R _{522 to} R ₅₂₇ , R _{532 to} R ₅₃₇ , R _{542 to} R ₅₄₈ , R _{552 to} R ₅₅₈ , R _{562 to} R ₅₆₇ , R _{572 to} R ₅₇₇ each independently represents a hydrogen atom or a substituent, and the substituents may be the same or different. ]
(18th aspect)
The compound represented by the general formula (1) is represented by the following general formula (3). The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{601 to} R ₆₀₆ each independently represents a hydrogen atom or a substituent, and at least one of R _{601 to} R ₆₀₆ is represented by Formulas (2-1) to (2-4). Represents at least one group selected from the following groups. ]
(19th aspect)
The compound represented by the general formula (1) is represented by the following general formula (4), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{611 to} R ₆₂₀ each independently represents a hydrogen atom or a substituent, and at least one of R _{611 to} R ₆₂₀ is represented by the general formulas (2-1) to (2-4). Represents at least one group selected from the following groups. ]
(20th aspect)
The compound represented by the general formula (1) is represented by the following general formula (5), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{621 to} R ₆₂₃ each independently represents a hydrogen atom or a substituent, and at least one of R _{621 to} R ₆₂₃ is represented by Formulas (2-1) to (2-4). Represents at least one group selected from the following groups. ]
(21st aspect)
The compound represented by the general formula (1) is represented by the following general formula (6), The organic electroluminescent element according to any one of the second to sixth aspects.

[Wherein, R _{631 to} R ₆₄₅ each independently represent a hydrogen atom or a substituent, and at least one of R _{631 to} R ₆₄₅ is represented by the above general formulas (2-1) to (2-4). Represents at least one group selected from the following groups. ]
(Twenty-second aspect)
The compound represented by the general formula (1) is represented by the following general formula (7). The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{651 to} R ₆₅₆ each independently represents a hydrogen atom or a substituent, and at least one of R _{651 to} R ₆₅₆ is represented by Formulas (2-1) to (2-4). Represents at least one group selected from the following groups. na represents an integer of 0 to 5, and nb represents an integer of 1 to 6, but the sum of na and nb is 6. ]
(23rd aspect)
The compound represented by the general formula (1) is represented by the following general formula (8), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{661 to} R ₆₇₂ each independently represents a hydrogen atom or a substituent, and at least one of R _{661 to} R ₆₇₂ is represented by the general formulas (2-1) to (2-4). Represents at least one group selected from the following groups. ]
(24th aspect)
The compound represented by the general formula (1) is represented by the following general formula (9), The organic electroluminescent element according to any one of the second to sixth aspects.

[Wherein, R _{681 to} R ₆₈₈ each independently represents a hydrogen atom or a substituent, and at least one of R _{681 to} R ₆₈₈ is represented by the general formulas (2-1) to (2-4). Represents at least one group selected from the following groups. ]
(25th aspect)
The compound represented by the general formula (1) is represented by the following general formula (10), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R _{691 to} R ₇₀₀ each independently represents a hydrogen atom or a substituent, and L ₁ represents a divalent linking group. At least one of R _{691 to} R ₇₀₀ represents at least one group selected from the groups represented by the general formulas (2-1) to (2-4). ]
(26th aspect)
The compound represented by the general formula (1) is represented by the following general formula (11), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(27th aspect)
The compound represented by the general formula (1) is represented by the following general formula (12), The organic electroluminescent element according to any one of the second to sixth aspects.

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(28th aspect)
The compound represented by the general formula (1) is represented by the following general formula (13), The organic electroluminescence device according to any one of the second to sixth aspects.

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(29th aspect)
The compound represented by the general formula (1) is represented by the following general formula (14), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. ]
(30th aspect)
The compound represented by the general formula (1) is represented by the following general formula (15), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, R ₁ and R ₂ each independently represents a hydrogen atom or a substituent. n and m each represent an integer of 1 to 2, and k and l each represent an integer of 3 to 4. However, n + k = 5 and l + m = 5. Z ₁ , Z ₂ , Z ₃ and Z ₄ each represents a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom. ]
(Thirty-first aspect)
The compound represented by the general formula (1) is represented by the following general formula (16), and the organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, o and p each represent an integer of 1 to 3, and Ar ₁ and Ar ₂ each represent an arylene group or a divalent aromatic heterocyclic group. Z ₁ and Z ₂ each represents a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom, and L represents a divalent linking group. ]
(Thirty-second aspect)
The compound represented by the general formula (1) is represented by the following general formula (17), The organic electroluminescence element according to any one of the second to sixth aspects.

[Wherein, o and p each represent an integer of 1 to 3, and Ar ₁ and Ar ₂ each represent a divalent arylene group or a divalent aromatic heterocyclic group. Z ₁ , Z ₂ , Z ₃ and Z ₄ each represents a 6-membered aromatic heterocyclic ring containing at least one nitrogen atom, and L represents a divalent linking group. ]
(Thirty-third aspect)
The organic electroluminescence element according to any one of the first to thirty-second aspects, wherein the second electrode is formed by a sputtering method.

(34th aspect)
The organic light-emitting device according to any one of the first to thirty-third aspects, wherein the light-emitting layer is a phosphorescent light-emitting layer.

(35th aspect)
The organic electroluminescent element according to any one of the first to thirty-fourth aspects, wherein the compound represented by the general formula (A) is contained in a light emitting layer.

(Thirty-sixth aspect)
In any one of the first to thirty-fifth aspects, the constituent layer includes at least one electron transport layer, and the electron transport layer contains a compound represented by the general formula (A). The organic electroluminescent element of description.

(Thirty-seventh aspect)
37. The organic electroluminescent element according to any one of the thirty-fourth to thirty-sixth aspects, wherein the phosphorescent light-emitting layer contains osmium, iridium, rhodium, or a platinum complex compound.

(38th aspect)
The organic electroluminescence element according to any one of the first to thirty-seventh aspects, which emits white light.

(39th aspect)
A display device comprising the organic electroluminescence element according to any one of the first to thirty-eighth aspects.

(40th aspect)
A lighting apparatus comprising the organic electroluminescence element according to any one of the first to thirty-eighth aspects.

(41st aspect)
40. A display device comprising: the lighting device according to the 40th aspect; and a liquid crystal element as display means.

  According to the present invention, it is possible to provide an organic electroluminescence element that exhibits high light emission efficiency, has a long light emission lifetime, and has reduced light emission defects, and a display device and an illumination device that include the organic electroluminescence element.

It is the schematic diagram which showed an example of the display apparatus comprised from an organic EL element. It is a schematic diagram of a display part. It is a schematic diagram of a pixel. It is a schematic diagram of a passive matrix type full-color display device. It is a schematic diagram which shows an example of the organic EL element which has a sealing structure. It is a schematic diagram which shows an example of the layer structure of a bottom emission type organic EL element. It is a schematic diagram which shows an example of the layer structure of a top emission type organic EL element. It is a schematic diagram which shows an example of the board | substrate which has TFT used for an organic EL element.

  In the organic electroluminescence device of the present invention, by adopting the configuration defined in any one of claims 1 to 39, the second electrode is not damaged during the formation of the second electrode, the luminous efficiency is high, and the luminous lifetime is high. It was possible to obtain an organic EL device that was long and had reduced light emission defects. Furthermore, a high-luminance display device and illumination device could be obtained using the organic EL element.

  Hereinafter, details of each component according to the present invention will be sequentially described.

  In order to improve the reduction in light emission efficiency caused by the driving element 205 blocking light emission, which is a problem of the conventional organic EL element as shown in FIG. 7 is the same as FIG. 6), and a method of taking out light emission from the cathode side as shown in FIG. 6 is studied. At that time, when forming a transparent electrode provided as a cathode, high energy is obtained. Even when applied to an organic thin film layer (for example, an electron transport layer), various means for reducing damage are studied, and an organic layer formed using a compound represented by the general formula (A) according to the present invention (for example, It was found that the electron transport layer or the like was not thermally damaged even during the production of the transparent electrode, and as a result, the generation of dark spots due to a decrease in luminous efficiency and local heat generation was suppressed.

  Hereinafter, the compound represented by formula (A) will be described in detail.

<< Compound Represented by Formula (A) >>
The compound represented by the general formula (A) according to the present invention may be contained in any constituent layer of the organic EL device of the present invention. From the viewpoint of more preferably obtaining the effects described in the present invention, The compound represented by the general formula (A) is preferably contained in the light emitting layer or the electron transport layer described later. Moreover, when used for a light emitting layer, it is preferably used as a host compound.

In General Formula (A), any one of X _{1 to} X ₈ is a carbon atom, and each of the substituents represented by R _{1 to} R ₈ bonded to the carbon atom includes an alkyl group (for example, methyl Group, ethyl group, propyl group, isopropyl group, tert-butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, etc.), cycloalkyl group (for example, cyclopentyl group, cyclohexyl group) Etc.), alkenyl groups (for example, vinyl groups, allyl groups, etc.), alkynyl groups (for example, ethynyl groups, propargyl groups, etc.), aryl groups (for example, phenyl groups, naphthyl groups, etc.), aromatic heterocyclic groups (for example, Furyl, thienyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl, imidazolyl, Zolyl group, thiazolyl group, quinazolinyl group, phthalazinyl group, etc.), heterocyclic group (eg, pyrrolidyl group, imidazolidyl group, morpholyl group, oxazolidyl group, etc.), alkoxyl group (eg, methoxy group, ethoxy group, propyloxy group, pentyl) Oxy group, hexyloxy group, octyloxy group, dodecyloxy group, etc.), cycloalkoxyl group (eg, cyclopentyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, naphthyloxy group, etc.), alkylthio group (Eg, methylthio group, ethylthio group, propylthio group, pentylthio group, hexylthio group, octylthio group, dodecylthio group, etc.), cycloalkylthio group (eg, cyclopentylthio group, cyclohexylthio group, etc.), arylthio group (eg, Phenylthio group, naphthylthio group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, octyloxycarbonyl group, dodecyloxycarbonyl group, etc.), aryloxycarbonyl group (eg, Phenyloxycarbonyl group, naphthyloxycarbonyl group, etc.), sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylaminosulfonyl group, octylaminosulfonyl group) , Dodecylaminosulfonyl group, phenylaminosulfonyl group, naphthylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), acyl group (for example, acetyl) Group, ethylcarbonyl group, propylcarbonyl group, pentylcarbonyl group, cyclohexylcarbonyl group, octylcarbonyl group, 2-ethylhexylcarbonyl group, dodecylcarbonyl group, phenylcarbonyl group, naphthylcarbonyl group, pyridylcarbonyl group, etc.), acyloxy group ( For example, acetyloxy group, ethylcarbonyloxy group, butylcarbonyloxy group, octylcarbonyloxy group, dodecylcarbonyloxy group, phenylcarbonyloxy group, etc.), amide group (for example, methylcarbonylamino group, ethylcarbonylamino group, dimethylcarbonyl) Amino group, propylcarbonylamino group, pentylcarbonylamino group, cyclohexylcarbonylamino group, 2-ethylhexylcarbonylamino group, octylcarbo Ruamino group, dodecylcarbonylamino group, phenylcarbonylamino group, naphthylcarbonylamino group, etc.), carbamoyl group (for example, aminocarbonyl group, methylaminocarbonyl group, dimethylaminocarbonyl group, propylaminocarbonyl group, pentylaminocarbonyl group, cyclohexyl). Aminocarbonyl group, octylaminocarbonyl group, 2-ethylhexylaminocarbonyl group, dodecylaminocarbonyl group, phenylaminocarbonyl group, naphthylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), ureido group (for example, methylureido group, ethylureido) Group, pentylureido group, cyclohexylureido group, octylureido group, dodecylureido group, phenylureido group, naphthylureido group, 2-pyridy Aminoureido groups, etc.), sulfinyl groups (for example, methylsulfinyl group, ethylsulfinyl group, butylsulfinyl group, cyclohexylsulfinyl group, 2-ethylhexylsulfinyl group, dodecylsulfinyl group, phenylsulfinyl group, naphthylsulfinyl group, 2-pyridylsulfinyl group) Etc.), alkylsulfonyl group (for example, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, 2-ethylhexylsulfonyl group, dodecylsulfonyl group, etc.), arylsulfonyl group (phenylsulfonyl group, naphthylsulfonyl group, 2 -Pyridylsulfonyl group, etc.), amino group (for example, amino group, ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, 2-ethyl Xylamino group, dodecylamino group, anilino group, naphthylamino group, 2-pyridylamino group, etc.), halogen atom (eg, fluorine atom, chlorine atom, bromine atom etc.), fluorinated hydrocarbon group (eg, fluoromethyl group, trimethyl group) Fluoromethyl group, pentafluoroethyl group, pentafluorophenyl group, etc.), cyano group, nitro group, hydroxyl group, mercapto group, silyl group (for example, trimethylsilyl group, triisopropylsilyl group, triphenylsilyl group, phenyldiethylsilyl group) Etc.).

  These substituents may be further substituted with the above substituents. In addition, a plurality of these substituents may be bonded to each other to form a ring.

  Preferred substituents are an alkyl group, a cycloalkyl group, a fluorinated hydrocarbon group, an aryl group, and an aromatic heterocyclic group.

Adjacent R _{1 to} R ₈ may be bonded to each other to form a ring.

In the general formula (A), the substituent represented by R ₉ has the same meaning as the substituents represented by R _{1 to} R ₈ in the general formula (A).

  Furthermore, among the compounds represented by the general formula (A) of the present invention, the compounds represented by the following general formula (1) are preferably used.

<< Compound Represented by Formula (1) >>
The compound represented by the general formula (1) according to the present invention will be described.

  As a result of intensive studies, the present inventors have found that the organic EL device using the compound represented by the general formula (1) has high luminous efficiency. Furthermore, it discovered that the organic EL element using the compound represented by the said General formula (1) became long life.

In the general formula (1), Z ₁ represents an aromatic heterocyclic ring which may have a substituent, and Z ₂ represents an aromatic heterocyclic ring or an aromatic hydrocarbon ring which may have a substituent. , Z ₃ represents a divalent linking group or a simple bond. R ₁₀₁ represents a hydrogen atom or a substituent.

In the general formula (1), examples of the aromatic heterocycle represented by Z ₁ and Z ₂ include a furan ring, a thiophene ring, a pyridine ring, a pyridazine ring, a pyrimidine ring, a pyrazine ring, a triazine ring, a benzimidazole ring, Diazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, carboline ring, carboline ring And a ring in which the carbon atom of the hydrocarbon ring is further substituted with a nitrogen atom. Furthermore, the aromatic heterocyclic ring may have a substituent represented by R ₁₀₁ described later.

In the general formula (1), examples of the aromatic hydrocarbon ring represented by Z ₂ include a benzene ring, a biphenyl ring, a naphthalene ring, an azulene ring, an anthracene ring, a phenanthrene ring, a pyrene ring, a chrysene ring, a naphthacene ring, and triphenylene. Ring, o-terphenyl ring, m-terphenyl ring, p-terphenyl ring, acenaphthene ring, coronene ring, fluorene ring, fluoranthrene ring, naphthacene ring, pentacene ring, perylene ring, pentaphen ring, picene ring, pyrene Ring, pyranthrene ring, anthraanthrene ring and the like. Furthermore, the aromatic hydrocarbon ring may have a substituent represented by R ₁₀₁ .

In the general formula (1), as the substituent represented by R ₁₀₁ , any one of X _{1 to} X ₈ in the general formula (A) is a carbon atom, and R ₁ bonded to the carbon atom. it is synonymous with the substituent represented by each by to R _8.

  The divalent linking group may include a hydrocarbon group such as an alkylene group, an alkenylene group, an alkynylene group, an arylene group, a hetero atom, a thiophene-2,5-diyl group, It may be a divalent linking group derived from a compound having an aromatic heterocycle (also called a heteroaromatic compound) such as a pyrazine-2,3-diyl group, or may be a chalcogen atom such as oxygen or sulfur. There may be. Further, it may be a group linked via a hetero atom such as an alkylimino group, a dialkylsilanediyl group or a diarylgermandiyl group.

  A mere bond is a bond that directly bonds the connecting substituents together.

As a specific example of the divalent linking group, the same divalent linking group represented by L ₁ in general formula (10) described later can be used.

In the present invention, Z _{1 in the} general formula (1) is preferably a 6-membered ring. Thereby, luminous efficiency can be made higher. Furthermore, the lifetime can be further increased.

In the present invention, it is preferable that the Z ₂ in the general formula (1) is a 6-membered ring. Thereby, luminous efficiency can be made higher. Furthermore, the lifetime can be further increased.

Furthermore, it is preferable that Z ₁ and Z _{2 in} the general formula (1) are both 6-membered rings because the luminous efficiency can be further increased. Furthermore, it is preferable because the lifetime can be further increased.

  Preferred among the compounds represented by the general formula (1) are compounds represented by the general formulas (1-1) to (1-13).

In the general formula (1-1), R _{501 to} R ₅₀₇ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-1), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-2), R _{511 to} R ₅₁₇ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-2), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-3), R _{521 to} R ₅₂₇ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-3), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-4), R _{531 to} R ₅₃₇ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-4), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In Formula _{(1-5), R} 541 ~R ₅₄₈ each independently represents a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-5), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-6), R _{551 to} R ₅₅₈ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-6), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-7), R _{561 to} R ₅₆₇ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-7), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (1-8), R _{571 to} R ₅₇₇ each independently represent a hydrogen atom or a substituent.

  By using the compound represented by the general formula (1-8), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

  In the general formula (1-9), R represents a hydrogen atom or a substituent. The plurality of R may be the same or different.

  By using the compound represented by the said General formula (1-9), it can be set as an organic electroluminescent element with higher luminous efficiency. Furthermore, it can be set as a longer life organic EL element.

  In the general formula (1-10), R represents a hydrogen atom or a substituent. The plurality of R may be the same or different.

  By using the compound represented by the general formula (1-10), an organic EL device with higher luminous efficiency can be obtained. Furthermore, a long-life organic EL element can be obtained.

In addition, the compound represented by the general formula (1) is preferably a compound having at least one group represented by any one of the general formulas (2-1) to (2-8). In particular, it is more preferable to have 2 to 4 groups represented by any one of the general formulas (2-1) to (2-8) in the molecule. In this case, the structure represented by the general formula (1) includes a case where the portion excluding R ₁₀₁ is replaced by the general formulas (2-1) to (2-8).

  At this time, the compounds represented by the general formulas (3) to (17) are particularly preferable for obtaining the effects of the present invention.

In the general formula (3), R _{601 to} R _{606 each} represents a hydrogen atom or a substituent, and at least one of R _{601 to} R ₆₀₆ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

  By using the compound represented by the general formula (3), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (4), R _{611 to} R ₆₂₀ represent a hydrogen atom or a substituent, and at least one of R _{611 to} R ₆₂₀ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

  By using the compound represented by the general formula (4), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (5), R _{621 to} R ₆₂₃ represent a hydrogen atom or a substituent, and at least one of R _{621 to} R ₆₂₃ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

  By using the compound represented by the general formula (5), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (6), R _{631 to} R ₆₄₅ represent a hydrogen atom or a substituent, and at least one of R _{631 to} R ₆₄₅ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

  By using the compound represented by the general formula (6), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (7), R _{651 to} R ₆₅₆ represent a hydrogen atom or a substituent, and at least one of R _{651 to} R ₆₅₆ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented. na represents an integer of 0 to 5, and nb represents an integer of 1 to 6, but the sum of na and nb is 6.

  By using the compound represented by the general formula (7), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (8), R _{661 to} R ₆₇₂ represent a hydrogen atom or a substituent, and at least one of R _{661 to} R ₆₇₂ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

  By using the compound represented by the general formula (8), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (9), R _{681 to} R ₆₈₈ represent a hydrogen atom or a substituent, and at least one of R _{681 to} R ₆₈₈ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

  By using the compound represented by the general formula (9), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the general formula (10), R _{691 to} R ₇₀₀ represent a hydrogen atom or a substituent, and at least one of R _{691 to} R ₇₀₀ is represented by the general formulas (2-1) to (2-4). The group represented by either is represented.

In the general formula (10), the divalent linking group represented by L ₁ is an alkylene group (for example, ethylene group, trimethylene group, tetramethylene group, propylene group, ethylethylene group, pentamethylene group, hexamethylene). Group, 2,2,4-trimethylhexamethylene group, heptamethylene group, octamethylene group, nonamethylene group, decamethylene group, undecamethylene group, dodecamethylene group, cyclohexylene group (for example, 1,6-cyclohexanediyl group, etc.) ), Cyclopentylene group (eg, 1,5-cyclopentanediyl group, etc.), alkenylene group (eg, vinylene group, propenylene group, etc.), alkynylene group (eg, ethynylene group, 3-pentynylene group, etc.), In addition to hydrocarbon groups such as arylene groups, groups containing heteroatoms (eg, —O A divalent group containing a chalcogen atom such as-or -S-, -N (R)-group, wherein R represents a hydrogen atom or an alkyl group, and the alkyl group in the general formula (1) And the same as the alkyl group represented by R ₁₀₁ ).

  In each of the alkylene group, alkenylene group, alkynylene group, and arylene group, at least one of carbon atoms constituting the divalent linking group is a chalcogen atom (oxygen, sulfur, etc.) or -N (R). -It may be substituted with a group or the like.

Furthermore, as the divalent linking group represented by L ₁ , for example, a group having a divalent heterocyclic group is used. For example, an oxazolediyl group, a pyrimidinediyl group, a pyridazinediyl group, a pyrandiyl group, a pyrrolindiyl group. Group, imidazoline diyl group, imidazolidine diyl group, pyrazolidine diyl group, pyrazoline diyl group, piperidine diyl group, piperazine diyl group, morpholine diyl group, quinuclidine diyl group and the like, and thiophene-2,5- A divalent linking group derived from a compound having an aromatic heterocyclic ring (also referred to as a heteroaromatic compound) such as a diyl group or a pyrazine-2,3-diyl group may be used.

  Further, it may be a group that meets and links heteroatoms such as an alkylimino group, a dialkylsilanediyl group, or a diarylgermandiyl group.

  By using the compound represented by the general formula (10), an organic EL device with higher luminous efficiency can be obtained. Furthermore, it can be set as a longer life organic EL element.

In the compounds represented by the general formula (11) to the general formula (15), the substituents represented by R ₁ and R ₂ are the substituents represented by R ₁₀₁ in the general formula (1). At the same time as the group.

In the general formula (15), examples of the 6-membered aromatic heterocyclic ring each containing at least one nitrogen atom represented by Z ₁ , Z ₂ , Z ₃ and Z ₄ include a pyridine ring and a pyridazine ring. , Pyrimidine ring, pyrazine ring and the like.

In the general formula (16), examples of the 6-membered aromatic heterocycle each containing at least one nitrogen atom represented by Z ₁ and Z ₂ include a pyridine ring, pyridazine ring, pyrimidine ring, and pyrazine ring. Etc.

In the general formula (16), the arylene groups represented by Ar ₁ and Ar ₂ are o-phenylene group, m-phenylene group, p-phenylene group, naphthalenediyl group, anthracenediyl group, naphthacenediyl group, and pyrenediyl group. Group, naphthylnaphthalenediyl group, biphenyldiyl group (for example, 3,3′-biphenyldiyl group, 3,6-biphenyldiyl group, etc.), terphenyldiyl group, quaterphenyldiyl group, kinkphenyldiyl group, sexi Examples thereof include a phenyldiyl group, a septiphenyldiyl group, an octylphenyldiyl group, a nobiphenyldiyl group, and a deciphenyldiyl group. The arylene group may further have a substituent described later.

In the general formula (16), the divalent aromatic heterocyclic groups represented by Ar ₁ and Ar ₂ are furan ring, thiophene ring, pyridine ring, pyridazine ring, pyrimidine ring, pyrazine ring, triazine ring, benzo Imidazole ring, oxadiazole ring, triazole ring, imidazole ring, pyrazole ring, thiazole ring, indole ring, benzimidazole ring, benzothiazole ring, benzoxazole ring, quinoxaline ring, quinazoline ring, phthalazine ring, carbazole ring, carboline ring, And divalent groups derived from a ring in which the carbon atom of the hydrocarbon ring constituting the carboline ring is further substituted with a nitrogen atom. Furthermore, the aromatic heterocyclic group may have a substituent represented by R ₁₀₁ .

In the general formula (16), the divalent linking group represented by L has the same meaning as the divalent linking group represented by L ₁ in the general formula (10), but is preferably an alkylene group. , —O—, —S— and the like, are divalent groups containing a chalcogen atom, most preferably an alkylene group.

In the general formula _(17), in Ar 1, Ar _2, the arylene group represented by each, in the general formula _(16), is synonymous with the arylene group represented by each of Ar 1, Ar _2.

In the general formula _(17), an aromatic heterocyclic group represented by each of Ar 1, Ar _2, in the general formula _(16), the divalent aromatic heterocyclic ring represented by each of Ar 1, Ar ₂ Synonymous with group.

In the general formula (17), examples of the 6-membered aromatic heterocyclic ring each containing at least one nitrogen atom represented by Z ₁ , Z ₂ , Z ₃ , and Z ₄ include a pyridine ring and a pyridazine ring. , Pyrimidine ring, pyrazine ring and the like.

In the general formula (17), the divalent linking group represented by L has the same meaning as the divalent linking group represented by L ₁ in the general formula (10), but is preferably an alkylene group. , —O—, —S— and the like, are divalent groups containing a chalcogen atom, most preferably an alkylene group.

  Although the specific example of a compound represented by General formula (1) based on this invention below is shown, this invention is not limited to these.

  The azacarbazole ring and chloroplasts of these materials for organic EL devices are described in J. Org. Chem. Soc. PerkinTrans. 1, 1505-1510 (1999), Pol. J. et al. Chem. , 54, 1585 (1980), (Tetrahedron Lett. 41 (2000), 481-484).

  Introduction of the synthesized azacarbazole ring or its chloroplast to the core or linking group of an aromatic hydrocarbon ring, aromatic heterocycle, aromatic ring, heterocycle, alkyl group, etc. is based on Ullman coupling, Pd catalyst A known method such as coupling using Suzuki or Suzuki coupling can be used.

  The compound represented by the general formula (A) according to the present invention preferably has a molecular weight of 400 or more.

  Next, although the preferable specific example of the layer structure of the organic EL element of this invention is shown below, this invention is not limited to these.

I: anode / light emitting layer / cathode II: anode / light emitting layer / electron transport layer / cathode III: anode / anode buffer layer / light emitting layer / cathode IV: anode / anode buffer layer / light emitting layer / hole blocking layer / electron transport Layer / cathode V: anode / hole transport layer / light emitting layer / electron transport layer / cathode VI: anode / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode VII: anode / hole transport layer / Light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode VIII: anode / anode buffer layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / cathode buffer layer / cathode << light emission layer"
The light-emitting layer according to the present invention contains a light-emitting material, and is a layer that emits light by recombination of electrons and holes injected from an electrode, an electron transport layer, or a hole transport layer, and the light-emitting portion is a light-emitting layer The interface between the light emitting layer and the adjacent layer may be used.

  In the present invention, a phosphorescent compound is preferably used as the light emitting material. Thereby, high light emission luminance and light emission efficiency can be obtained. A phosphorescent compound is a compound in which light emission from an excited triplet is observed, is a compound that emits phosphorescence at room temperature (25 ° C.), and has a phosphorescence quantum yield of 0.01 or more at 25 ° C. It is. The phosphorescence quantum yield is preferably 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence quantum yield used in the present invention only needs to achieve the above phosphorescence quantum yield in any solvent.

  There are two types of light emission of phosphorescent compounds in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is phosphorescent. Energy transfer type to obtain light emission from the phosphorescent compound by transferring to the compound, the other is that the phosphorescent compound becomes a carrier trap, carrier recombination occurs on the phosphorescent compound, and from the phosphorescent compound In any case, the excited state energy of the phosphorescent compound is lower than the excited state energy of the host compound.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of the organic EL device.

  The mixing ratio with the light-emitting dopant for the light-emitting host in the light-emitting layer (by the way, the phosphorescent compound according to the present invention described later is a kind of light-emitting dopant) is preferably 0.1% by mass to 30% by mass. It is adjusting to the range of less than mass%.

  In the present invention, the phosphorescent compound is preferably an osmium, iridium, rhodium or platinum complex compound, whereby the luminance and luminous efficiency can be further improved.

  The phosphorescent compound (also referred to as phosphorescent compound) used in the present invention preferably has a phosphorescence quantum yield in solution of 0.001 or more at 25 ° C., more preferably 0.01 or more. Particularly preferably, it is 0.1 or more.

  The host compound used in the present invention is a compound having a phosphorescence quantum yield of phosphorescence emission of less than 0.01 at room temperature (25 ° C.) among compounds contained in the light emitting layer.

  The phosphorescent quantum yield can be measured by the method described in the fourth edition of Experimental Chemistry Course 7, Spectroscopy II, page 398 (1992 edition, Maruzen). Specific examples of phosphorescent compounds used in the present invention are as follows. Examples are shown, but the invention is not limited to these. These compounds are described, for example, in Inorg. Chem. 40, 1704-1711, and the like.

  In addition, as the phosphorescent compound (luminescent dopant), the compounds described in the following public relations can also be used.

  For example, International Publication No. 00/70655 pamphlet, Japanese Patent Application Laid-Open No. 2002-280178, Japanese Patent Application Laid-Open No. 2001-181616, Japanese Patent Application Laid-Open No. 2002-280179, Japanese Patent Application Laid-Open No. 2001-181617, and Japanese Patent Application Laid-Open No. 2002-280180. JP, 2001-247859, JP, 2002-299060, JP, 2001-313178, JP, 2002-302671, JP, 2001-345183, JP, 2002-324679, International, Publication No. 02/15645, JP 2002-332291 A, JP 2002-50484 A, JP 2002-332292 A, JP 2002-83684 A, JP 2002-540572 A, JP 2002-117978, JP 2002-338588, JP 2002-170684, JP 2002-352960, WO 01/93642, JP 2002-50483, JP 2002-1000047, JP JP 2002-173684 A, JP 2002-359082 A, JP 2002-17584 A, JP 2002-363552 A, JP 2002-184582 A, JP 2003-7469 A, Special Table 2002. No. 525808, JP 2003-7471, JP 2002-525833, JP 2003-31366, JP 2002-226495, JP 2002-234894, JP 2002-233506 Japanese Patent Laid-Open No. 2002-24175 JP, JP 2001-319779, JP 2001-319780, JP 2002-62824, JP 2002-1000047, JP 2002-203679, 2002-343572. JP, 2002-203678, A, etc. are mentioned.

  In the present invention, the phosphorescent maximum wavelength of the phosphorescent compound is not particularly limited, and in principle, the emission wavelength obtained by selecting a central metal, a ligand, a ligand substituent, and the like. However, it is preferable that the phosphorescence emission wavelength of the phosphorescent compound has a maximum phosphorescence emission wavelength of 380 to 480 nm. Such a blue phosphorescent organic EL element or a white phosphorescent organic EL element can be an organic electroluminescent element having higher emission luminance and a longer half-life.

  In addition, by using a plurality of phosphorescent compounds, it is possible to mix different light emission, thereby obtaining an arbitrary emission color. White light emission is possible by adjusting the kind of phosphorescent compound and the amount of doping, and can also be applied to lighting devices and backlights.

  In the light emitting layer, a plurality of known host compounds may be used in combination. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. As these known host compounds, compounds having a hole transporting ability and an electron transporting ability, preventing the emission of longer wavelengths, and having a high Tg (glass transition temperature) are preferable.

  Specific examples of known host compounds include compounds described in the following documents.

  JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445 gazette, 2002-343568 gazette, 2002-141173 gazette, 2002-352957 gazette, 2002-203683 gazette, 2002-363227 gazette, 2002-231453 gazette, No. 003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060, No. 2002. -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

  Further, the light emitting layer may contain a fluorescent compound having a longer fluorescent maximum wavelength. In this case, energy transfer from the host compound and the phosphorescent compound to the fluorescent compound allows electroluminescence as an organic EL element to be emitted from the fluorescent compound. The fluorescent compound preferably has a high fluorescence quantum yield in a solution state. Here, the fluorescence quantum yield of the fluorescent compound is preferably 10% or more, particularly preferably 30% or more. Specific fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzoanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes. , Stilbene dyes, polythiophene dyes, and the like. The fluorescence quantum yield can be measured by the method described in 362 (1992 edition, Maruzen) of Spectroscopic II of the Fourth Edition Experimental Chemistry Course 7.

  The color emitted in this specification is the spectral radiance meter CS-1000 (Minolta) in FIG. 4.16 on page 108 of “New Color Science Handbook” (Edited by the Japan Society for Color Science, University of Tokyo Press, 1985). It is determined by the color when the measured result is applied to the CIE chromaticity coordinates.

  The light emitting layer can be formed by forming the above compound by a known thinning method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method, but preferably by a spin coating method. is there. Although the film thickness as a light emitting layer does not have a restriction | limiting in particular, Usually, 5 nm-5 micrometers, Preferably it is chosen in the range of 5 nm-200 nm. The light emitting layer may have a single layer structure in which these phosphorescent compounds and host compounds are composed of one or more kinds, or may have a laminated structure composed of a plurality of layers having the same composition or different compositions. Good.

《Electron transport layer》
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer used in the present invention can be provided as a single layer or a plurality of layers. Further, when the electron transport layer is provided as an adjacent layer of the cathode, the compound represented by the general formula (A) according to the present invention is used for forming the electron transport layer of the organic EL device, thereby forming the cathode. As a result, it was found that an organic electroluminescence device having a high light emission efficiency, a long light emission lifetime, and reduced light emission defects can be obtained.

  The present inventors consider that one reason is that the compound represented by the general formula (A) according to the present invention has high heat resistance.

  In addition to the above, as an electron transport material (also serving as a hole blocking material) used for the electron transport layer, examples of materials used for the electron transport layer (hereinafter referred to as electron transport material) include nitro-substituted fluorene derivatives. , Diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane and anthrone derivatives, oxadiazole derivatives, and the like. Furthermore, in the above oxadiazole derivatives, thiadiazole derivatives in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and quinoxaline derivatives having a quinoxaline ring known as an electron-withdrawing group can also be used together as an electron transport material. It is.

  Furthermore, the electron transport layer only needs to have a function of transmitting electrons injected from the cathode to the light emitting layer, and any one of conventionally known compounds can be selected and used.

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, Tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg, Cu Metal complexes replaced with Ca, Sn, Ga, or Pb can also be used as electron transport materials. In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transport material. In addition, the distyrylpyrazine derivative exemplified as the material of the light emitting layer can also be used as an electron transport material, and similarly to the hole injection layer and the hole transport layer, inorganic such as n-type-Si and n-type-SiC. A semiconductor can also be used as an electron transport material.

  It is preferable that the preferable compound used for an electron carrying layer has a fluorescence maximum wavelength in 415 nm or less. That is, the compound used for the electron transport layer is preferably a compound that has an electron transport ability, prevents emission of longer wavelengths, and has a high Tg.

  The electron transport layer can be formed by thinning the electron transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of an electron carrying layer, Usually, it is about 5-5000 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

<< Injection layer: electron injection layer, hole injection layer >>
The injection layer is provided as necessary, and there are an electron injection layer and a hole injection layer, and as described above, exists between the anode and the light emitting layer or the hole transport layer, and between the cathode and the light emitting layer or the electron transport layer. You may let them.

  An injection layer is a layer provided between an electrode and an organic layer in order to reduce drive voltage and improve light emission luminance. “Organic EL element and its forefront of industrialization (issued by NTT Corporation on November 30, 1998) 2), Chapter 2, “Electrode Materials” (pages 123 to 166) in detail, and includes a hole injection layer (anode buffer layer) and an electron injection layer (cathode buffer layer).

  The details of the anode buffer layer (hole injection layer) are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069 and the like. As a specific example, copper phthalocyanine is used. Examples thereof include a phthalocyanine buffer layer represented by an oxide, an oxide buffer layer represented by vanadium oxide, an amorphous carbon buffer layer, and a polymer buffer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene. Among these, those using polydioxythiophenes are preferable, and thereby, an organic EL device that exhibits higher light emission luminance and light emission efficiency and has a longer lifetime can be obtained. The anode buffer layer is preferably provided between the anode and the light emitting layer and adjacent to the cathode and the light emitting layer. Thereby, it can be set as the organic EL element which shows much higher light-emitting luminance and luminous efficiency, and is further long-life.

  The details of the cathode buffer layer (electron injection layer) are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples thereof include strontium and aluminum. A metal buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide.

  The buffer layer (injection layer) is preferably a very thin film, and although it depends on the material, the film thickness is preferably in the range of 0.1 nm to 100 nm.

  As described above, the blocking layer is provided as necessary in addition to the basic constituent layer of the organic compound thin film. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). There is a hole blocking (hole blocking) layer.

"cathode"
As the cathode, a material having a work function (4 eV or less) metal, alloy, electrically conductive compound and a mixture thereof as an electrode material is used. These electrode materials are preferably produced by resistance heating vapor deposition, sputtering, or ion plating. In addition, as shown in FIG. 7, when light emission is extracted from the cathode 204 side, light is extracted from the cathode 204 side. Therefore, the material for forming the cathode 204 is a conductive and highly light-transmitting material. For example, a transparent conductive oxide such as tin oxide, indium oxide, zinc oxide, antimony oxide, gallium oxide, germanium oxide, aluminum oxide, or a mixture thereof can be used. Further, as shown in FIG. 7, in the organic EL element of the present invention that extracts light emission from the cathode 204 side, the cathode 204 on the light extraction side can be manufactured by resistance heating vapor deposition, sputtering, or ion plating. preferable. The material for forming the cathode 204 is a conductive material that transmits visible light, for example, transparent materials such as tin oxide, indium oxide, zinc oxide, antimony oxide, gallium oxide, germanium oxide, and aluminum oxide. A conductive oxide or a mixture thereof can be used.

<Blocking layer: hole blocking layer, electron blocking layer>
The hole blocking layer is an electron transport layer in a broad sense, and is made of a material that has a function of transporting electrons and has a very small ability to transport holes. By blocking holes while transporting electrons, And the recombination probability of holes can be improved.

  The hole blocking layer has a role of blocking the holes moving from the hole transport layer from reaching the cathode and a compound that can efficiently transport the electrons injected from the cathode toward the light emitting layer. It is formed. The physical properties required of the material constituting the hole blocking layer are higher than the ionization potential of the light emitting layer in order to have high electron mobility and low hole mobility and to efficiently confine holes in the light emitting layer. It is preferable to have a value of ionization potential or a band gap larger than that of the light emitting layer.

  In the organic electroluminescence device of the present invention, it is preferable to provide a hole blocking layer adjacent to the light emitting layer. Thereby, the light emission luminance and the light emission efficiency can be further improved.

  In the organic EL device of the present invention, the hole blocking layer preferably contains at least one compound represented by the general formula (A), thereby further improving the luminance and luminous efficiency. be able to.

  On the other hand, the electron blocking layer is a hole transport layer in a broad sense, made of a material that has a function of transporting holes and has a very small ability to transport electrons, and blocks electrons while transporting holes. Thus, the probability of recombination of electrons and holes can be improved.

《Hole transport layer》
The hole transport layer which is one of the constituent layers of the organic EL device of the present invention will be described.

  The hole transport layer is made of a material having a function of transporting holes, and in a broad sense, a hole injection layer and an electron blocking layer are also included in the hole transport layer. The hole transport layer and the electron transport layer can be provided as a single layer or a plurality of layers.

  As the hole transport material, conventionally, any of photoconductive materials conventionally used as a charge injection transport material for holes, or a known material used for a hole injection layer or a hole transport layer of an EL element is arbitrarily selected. Can be selected and used.

  The hole transport material has one of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

  As the hole transport material, those described above can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

  Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N′-diphenyl-N, N ′ − (4-methoxyphenyl) -4,4′-diaminobiphenyl; N, N, N ′, N′-tetraphenyl-4,4′-diaminodiphenyl ether; 4,4′-bis (diphenylamino) quadriphenyl; N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 ′-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino- (2-diphenylvinyl) benzene; 3-methoxy-4′-N, N-diphenylaminostilbenzene; N-phenylcarbazole, and two more described in US Pat. No. 5,061,569 Having a condensed aromatic ring of, for example, 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-30 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 688 are linked in a starburst type (MTDATA).

  Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

  In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

  In the present invention, the hole transport material of the hole transport layer preferably has a fluorescence maximum wavelength at 415 nm or less. That is, the hole transport material is preferably a compound that has a hole transport ability, prevents the emission of light from becoming longer, and has a high Tg.

  This hole transport layer can be formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, an ink jet method, or an LB method. Although there is no restriction | limiting in particular about the film thickness of a positive hole transport layer, Usually, it is about 5-5000 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

"anode"
As the anode in the organic EL element, an electrode material made of a metal, an alloy, an electrically conductive compound, or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such an electrode substance include conductive transparent materials such as metals such as Au, CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, a thin film may be formed by depositing these electrode materials by a method such as vapor deposition or sputtering, and a pattern having a desired shape may be formed by a photolithography method, or when the pattern accuracy is not required (100 μm or more) Degree), a pattern may be formed through a mask having a desired shape when the electrode material is deposited or sputtered. As shown in FIG. 7, when extracting light from the cathode 204 side, the anode functions as a reflective electrode, so it is preferable to use a material with as high a reflectance as possible. Conversely, when extracting light from the anode, High translucency is desirable, and sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually selected in the range of 10 nm to 1000 nm, preferably 10 nm to 200 nm.

<< Substrate (also referred to as substrate, substrate, support, etc.) >>
The substrate that can be used in the organic EL device of the present invention is not particularly limited in the type of glass, plastic and the like. Examples of the substrate preferably used include glass, quartz, and resin film. In producing an active matrix light-emitting device using the organic EL element of the present invention, for example, a substrate in which a TFT 602 is formed on a glass substrate 601 is used as shown in FIG. A manufacturing method of the TFT 602 may follow a known TFT manufacturing method. Of course, the TFT may be a conventionally known top gate TFT or bottom gate TFT.

  The external extraction efficiency at room temperature of light emission of the organic electroluminescence device of the present invention is preferably 1% or more, more preferably 2% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

  Further, a hue improving filter such as a color filter may be used in combination.

  The multicolor display device of the present invention comprises at least two kinds of organic EL elements having different light emission maximum wavelengths, and a preferred example for producing the organic EL elements will be described.

<< Method for producing organic EL element >>
As an example of the method for producing the organic EL device of the present invention, a method for producing an organic EL device comprising an anode / anode buffer layer / light emitting layer / hole blocking layer / electron transport layer / cathode will be described.

  First, a layer made of a desired electrode material, for example, an anode material is formed on a suitable substrate by a method such as vapor deposition or sputtering so as to have a film thickness of 1 μm or less, preferably 10 nm to 200 nm. Make it. Next, an organic compound thin film of an anode buffer layer, a light emitting layer, a hole blocking layer, and an electron transport layer, which are element materials, is formed thereon.

As described above, there are spin coating methods, casting methods, ink jet methods, vapor deposition methods, printing methods, and the like as methods for thinning the organic compound thin films, but it is easy to obtain a uniform film and pinholes are not easily generated. In view of the above, the vacuum deposition method or the spin coating method is particularly preferable. Further, different film forming methods may be applied for each layer. When a vapor deposition method is employed for film formation, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 ° C. to 450 ° C., a vacuum degree of 10 ⁻⁶ Pa to 10 ⁻² Pa, and a vapor deposition rate of 0. It is desirable to select appropriately within a range of 0.01 nm to 50 nm / second, a substrate temperature of −50 ° C. to 300 ° C., and a film thickness of 0.1 nm to 5 μm.

  After the formation of these layers, a thin film made of a cathode material is formed thereon by a method such as vapor deposition or sputtering so as to have a thickness of 1 μm or less, preferably in the range of 50 nm to 200 nm, and a cathode is provided. Thus, a desired organic EL element can be obtained. The organic EL element is preferably produced from the hole injection layer to the cathode consistently by a single evacuation, but may be taken out halfway and subjected to different film forming methods. At that time, it is necessary to consider that the work is performed in a dry inert gas atmosphere.

  In the display device of the present invention, a shadow mask is provided only at the time of forming a light emitting layer, and the other layers are common, and a layer can be formed on one surface by a vapor deposition method, a cast method, a spin coating method, an ink jet method, a printing method, or the like.

  It is also possible to make each layer by reversing the production order.

  When a DC voltage is applied to the display device thus obtained, light emission can be observed by applying a voltage of about 2 to 40 V with the positive polarity of the anode and the negative polarity of the cathode. Further, even when a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The alternating current waveform to be applied may be arbitrary.

  The display device of the present invention uses the organic EL element of the present invention, and can be used as a display device, a display, and various light sources. In a display device or display, full-color display can be performed by using three types of organic EL elements of blue, red, and green light emission.

  Examples of the display device and the display include a television, a personal computer, a mobile device, an AV device, a character broadcast display, and an information display in a car. In particular, it may be used as a display device for reproducing still images and moving images, and the driving method when used as a display device for reproducing moving images may be either a simple matrix (passive matrix) method or an active matrix method.

  The lighting device of the present invention uses the organic EL element of the present invention, and is used for home lighting, interior lighting, clock backlight, billboard advertisement, traffic light, light source of optical storage medium, light source of electrophotographic copying machine, optical communication Examples include, but are not limited to, a light source for a processing machine and a light source for an optical sensor. It can also be used as a backlight for liquid crystal display devices and the like.

  Further, the organic EL element according to the present invention may be used as an organic EL element having a resonator structure.

  Examples of the purpose of use of the organic EL element having such a resonator structure include a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processing machine, and a light source of an optical sensor. It is not limited. Moreover, you may use for the said use by making a laser oscillation.

  As described above, the organic EL device of the present invention may be used as one kind of lamp for illumination or exposure light source, or a projection device for projecting an image, or directly viewing a still image or a moving image. It may be used as a type of display device (display). When used as a display device for reproducing moving images, the driving method may be either a simple matrix (passive matrix) method or an active matrix method. Alternatively, a full-color display device can be manufactured by using three or more organic EL elements of the present invention having different emission colors. Alternatively, it is possible to make one color emission color, for example, white emission, into BGR by using a color filter to achieve full color. Furthermore, it is possible to convert the emission color of the organic EL to another color by using a color conversion filter, and in this case, λmax of the organic EL emission is preferably 480 nm or less.

  An example of a display device composed of the organic EL element of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating an example of a display device including organic EL elements. It is a schematic diagram of a display such as a mobile phone that displays image information by light emission of an organic EL element.

  The display 1 includes a display unit A having a plurality of pixels, a control unit B that performs image scanning of the display unit A based on image information, and the like.

  The control unit B is electrically connected to the display unit A, and sends a scanning signal and an image data signal to each of the plurality of pixels based on image information from the outside. The pixels for each scanning line are converted into image data signals by the scanning signal. In response to this, light is sequentially emitted and image scanning is performed to display image information on the display unit A.

  FIG. 2 is a schematic diagram of the display unit A.

  The display unit A includes a wiring unit including a plurality of scanning lines 5 and data lines 6, a plurality of pixels 3 and the like on a substrate. The main members of the display unit A will be described below. FIG. 2 shows a case where the light emitted from the pixel 3 is extracted in the direction of the white arrow (downward).

  The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a grid pattern and are connected to the pixels 3 at orthogonal positions (details are shown in FIG. Not shown).

  When a scanning signal is applied from the scanning line 5, the pixel 3 receives an image data signal from the data line 6 and emits light according to the received image data. Full color display is possible by appropriately arranging pixels in the red region, the green region, and the blue region that emit light on the same substrate.

  Next, the light emission process of the pixel will be described.

  FIG. 3 is a schematic diagram of a pixel.

  The pixel includes an organic EL element 10, a switching transistor 11, a driving transistor 12, a capacitor 13, and the like. A full color display can be performed by using red, green, and blue light emitting organic EL elements as the organic EL elements 10 in a plurality of pixels, and juxtaposing them on the same substrate.

  In FIG. 3, an image data signal is applied from the control unit B to the drain of the switching transistor 11 through the data line 6. When a scanning signal is applied from the control unit B to the gate of the switching transistor 11 via the scanning line 5, the driving of the switching transistor 11 is turned on, and the image data signal applied to the drain is supplied to the capacitor 13 and the driving transistor 12. Is transmitted to the gate.

  By transmitting the image data signal, the capacitor 13 is charged according to the potential of the image data signal, and the drive of the drive transistor 12 is turned on. The drive transistor 12 has a drain connected to the power supply line 7 and a source connected to the electrode of the organic EL element 10, and the power supply line 7 connects to the organic EL element 10 according to the potential of the image data signal applied to the gate. Current is supplied.

  When the scanning signal is moved to the next scanning line 5 by the sequential scanning of the control unit B, the driving of the switching transistor 11 is turned off. However, even if the driving of the switching transistor 11 is turned off, the capacitor 13 maintains the potential of the charged image data signal, so that the driving of the driving transistor 12 is kept on and the next scanning signal is applied. Until then, the light emission of the organic EL element 10 continues. When the scanning signal is next applied by sequential scanning, the driving transistor 12 is driven according to the potential of the next image data signal synchronized with the scanning signal, and the organic EL element 10 emits light.

  That is, the organic EL element 10 emits light by providing a switching transistor 11 and a drive transistor 12 as active elements for each of the organic EL elements 10 of the plurality of pixels 3. Emitting light. Such a light emitting method is called an active matrix method.

  Here, the light emission of the organic EL element 10 may be light emission of a plurality of gradations by a multi-value image data signal having a plurality of gradation potentials, or on / off of a predetermined light emission amount by a binary image data signal. But you can.

  The potential of the capacitor 13 may be held continuously until the next scanning signal is applied, or may be discharged immediately before the next scanning signal is applied.

  In the present invention, not only the active matrix method described above, but also a passive matrix light emission drive in which the organic EL element emits light according to the data signal only when the scanning signal is scanned.

  FIG. 4 is a schematic view of a passive matrix display device. In FIG. 4, a plurality of scanning lines 5 and a plurality of image data lines 6 are provided in a lattice shape so as to face each other with the pixel 3 interposed therebetween.

  When the scanning signal of the scanning line 5 is applied by sequential scanning, the pixels 3 connected to the applied scanning line 5 emit light according to the image data signal. In the passive matrix system, the pixel 3 has no active element, and the manufacturing cost can be reduced.

  The organic EL material according to the present invention can also be applied to an organic EL element that emits substantially white light as a lighting device. A plurality of light emitting colors are simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include three emission maximum wavelengths of three primary colors of blue, green, and blue, or two using a complementary color relationship such as blue and yellow, blue green and orange, etc. The thing containing the light emission maximum wavelength may be used.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors includes a combination of a plurality of phosphorescent or fluorescent materials (light emitting dopants), a light emitting material that emits fluorescent or phosphorescent light, and the light emission. Any combination of a dye material that emits light from the material as excitation light may be used, but in the white organic electroluminescence device according to the present invention, a method of combining a plurality of light-emitting dopants is preferable.

  As a layer structure of an organic electroluminescence device for obtaining a plurality of emission colors, a method of having a plurality of emission dopants in one emission layer, a plurality of emission layers, and an emission wavelength in each emission layer And a method of forming minute pixels emitting light having different wavelengths in a matrix.

  In the white organic electroluminescence device according to the present invention, patterning may be performed by a metal mask, an ink jet printing method, or the like at the time of film formation, if necessary. When patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire element layer may be patterned.

  The light emitting material used for the light emitting layer is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the platinum complex according to the present invention is known so as to be suitable for the wavelength range corresponding to the CF (color filter) characteristics. Any one of the light emitting materials may be selected and combined to be whitened.

  Thus, in addition to the display device and display, the white light-emitting organic EL element of the present invention can be used as various light-emitting light sources, lighting devices, household lighting, interior lighting, and a kind of lamp such as an exposure light source. Further, it is also useful for display devices such as backlights for liquid crystal display devices.

  Others such as backlights for watches, signboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, light sources for optical sensors, etc. There are a wide range of uses such as household appliances.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these. The structural formulas of the compounds used in the examples are shown below.

Example 1
<< Production and Evaluation of Organic EL Elements 1-1 to 1-5 >>
On the substrate as an anode, aluminum was formed using a 150 nm metal mask, and after patterning, α-NPD was 20 nm as a hole transport layer and CBP and Ir− were used as a light emitting layer on the substrate provided with this aluminum electrode. 1 (100: 5) was 30 nm, BC was 10 nm as the first electron transport layer, and Alq ₃ was 40 nm as the second electron transport layer, and these were formed in this order by vacuum deposition. Next, the vacuum chamber is opened, and a stainless steel rectangular perforated mask is placed on the electron transport layer. Then, the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, and magnesium and silver (10 1) was formed by a 10 nm vacuum deposition method, and then an ITO layer was formed by a 100 nm sputtering method. A diamond-like carbon film was formed thereon by plasma CVD, and a light-transmitting glass substrate was attached and sealed using an ultraviolet curable adhesive to produce an organic EL element 1-1.

  In preparation of said organic EL element 1-1, except having changed BC used for the 1st electron carrying layer into the compound of Table 1, it is organic EL by the method similar to organic EL element 1-1. Elements 1-2 to 1-5 were respectively produced.

  The produced organic EL elements 1-1 to 1-5 were each prepared to have a sealing structure as shown in FIG. 5, 101 is a substrate, 102a is an anode, 102b is an organic EL layer (specifically, including the electron transport layer 208, the light emitting layer 207, and the hole transport layer 206 in FIG. 7), and 102c is a cathode. The light emitting element 102 is formed by the anode 102a, the organic EL layer 102b, and the cathode 102c. Reference numeral 103 denotes a sealing film.

  Each of the obtained organic EL elements 1-1 to 1-5 was evaluated as follows.

(Luminance brightness)
The produced organic EL device was measured for light emission luminance (L) [cd / m ² ] when a current of ^2.5 mA / cm ² was supplied in a dry nitrogen gas atmosphere at a temperature of 23 degrees. Here, CS-1000 (manufactured by Minolta) was used for measurement of light emission luminance and the like.

(External extraction quantum efficiency)
About the produced organic EL element, external extraction quantum efficiency (%) when ^2.5 mA / cm ² constant current was applied in a dry nitrogen gas atmosphere at 23 ° C. was measured. For the measurement, a spectral radiance meter CS-1000 (manufactured by Minolta) was used in the same manner.

(Half life / Luminescence defect)
When driving at a constant current of ^2.5 mA / cm ^{2 in} a dry nitrogen gas atmosphere at 23 ° C., the time required for the luminance to drop to half of the luminance immediately after the start of light emission (initial luminance) was measured. Was used as an index of life as half-life time (τ0.5). For the measurement, a spectral radiance meter CS-1000 (manufactured by Minolta) was used.

  In describing the evaluation results in Table 1, the light emission luminance, the external extraction quantum efficiency, and the light emission lifetime were expressed as relative values when each characteristic value of the organic EL element 1-1 was 100. In addition, the presence or absence of light emitting defects was measured at the initial stage and after 1000 hours. The obtained results are shown in Table 1.

  As is clear from Table 1, the organic EL device using the compound represented by the general formula (A) of the present invention for the first electron transporting layer has high luminous efficiency, prevents the occurrence of light emitting defects, and is stable. As a result, it was found that luminescence was obtained.

  Further, except that Ir-1 which is a phosphorescent compound is replaced with Ir-12, the organic EL elements 1-1B to 1-5B are similarly processed, and the same except that Ir-1 is replaced with Ir-9. Thus, organic EL elements 1-1R to 1-5R were produced. In each of the organic EL elements, the same effect as that obtained when Ir-1 was used was obtained. Note that blue light emission was obtained from the element using Ir-12, and red light emission was obtained from the element using Ir-9.

Reference example 2
<< Production and Evaluation of Organic EL Elements 2-1 to 2-5 >>
On the substrate as an anode, aluminum was formed using a 150 nm metal mask, and after patterning, α-NPD was 20 nm as a hole transport layer and CBP and Ir− were used as a light emitting layer on the substrate provided with this aluminum electrode. 1 (100: 5) was 30 nm, and Alq ₃ was 40 nm as an electron transport layer, which were formed in this order by vacuum deposition. Next, the vacuum chamber is opened and a stainless steel rectangular perforated mask is placed on the electron transport layer. Then, the vacuum chamber is decompressed to 4 × 10 ⁻⁴ Pa, and aluminum and lithium (10 1) was formed by a 10 nm vacuum vapor deposition method, and then an ITO layer was formed by a 100 nm sputtering method, and then the device was sealed in the same manner as in Example 1 to prepare an organic EL device 2-1.

  In the production of the organic EL element 2-1, the organic EL element 2-1 was prepared in the same manner as the organic EL element 2-1, except that the CBP used in the light emitting layer was changed to the compounds shown in Table 2. ˜2-5 were produced.

  Each of the obtained organic EL elements 2-1 to 2-5 was evaluated in the same manner as in Example 1 for light emission luminance, time to reduce the luminance by half, and the presence or absence of light emission defects, and the results obtained are shown in Table 2. Shown in

  In addition, each evaluation result of Table 2 was represented by the relative value when the light-emitting luminance, the external extraction quantum efficiency, and the half life of the organic EL element 2-1 were set to 100, respectively.

  As is clear from Table 2, it was found that even when the compound represented by the general formula (1) was used in the light emitting layer, the generation of light emitting defects was prevented with high light emission efficiency, and stable light emission was obtained. .

Example 3
<Full color display device>
(Blue light emitting organic EL device)
The organic EL element 1-5B produced in Example 1 was used.

(Green light-emitting organic EL device)
The organic EL element 1-5 produced in Example 1 was used.

(Red light emitting organic EL device)
The organic EL element 1-5R produced in Example 1 was used.

  The red, green and blue light-emitting organic EL elements are juxtaposed on the same substrate to produce an active matrix type full-color display device having the form shown in FIG. 1, and FIG. 2 shows the display of the produced display device. Only the schematic diagram of part A is shown. That is, a wiring portion including a plurality of scanning lines 5 and data lines 6 on the same substrate, and a plurality of juxtaposed pixels 3 (light emission color is a red region pixel, a green region pixel, a blue region pixel, etc.) The scanning lines 5 and the plurality of data lines 6 in the wiring portion are each made of a conductive material, and the scanning lines 5 and the data lines 6 are orthogonal to each other in a lattice shape and are connected to the pixels 3 at the orthogonal positions ( Details are not shown). The plurality of pixels 3 are driven by an active matrix system provided with an organic EL element corresponding to each emission color, a switching transistor as an active element, and a driving transistor, and a scanning signal is applied from a scanning line 5. Then, an image data signal is received from the data line 6 and light is emitted according to the received image data. In this way, a full color display device was produced by appropriately juxtaposing the red, green, and blue pixels.

  It was confirmed that by driving the full-color display device, a full-color moving image display having a high light emission efficiency and a long light emission life can be obtained.

Reference Example 4 (Example of producing a white organic EL element)
In the organic EL element 2-5 produced in Reference Example 2, the same procedure as in the organic EL element 1-1 except that Ir-1 used in the light emitting layer was changed to a mixture of Ir-1, Ir-9, and Ir-12. The organic EL element 2-5W produced by the method was used. The element could be used as a thin illuminating device that emits white light with high luminous efficiency and long emission lifetime.

DESCRIPTION OF SYMBOLS 1 Display 3 Pixel 5 Scan line 6 Data line 7 Power line 10 Organic EL element 11 Switching transistor 12 Drive transistor 13 Capacitor A Display part B Control part 101, 201 Board | substrate 102 Organic EL element 102a, 202 Anode 102b Organic EL layer 102c, 204 Cathode 103 Sealing film 205 Driving element 206 Hole transport layer 207 Light emitting layer 208 Electron transport layer 601 Substrate 602 TFT

Claims (1)

In the organic electroluminescent element in which the first electrode, the constituent layer including at least the light emitting layer and the electron transport layer, and the second electrode are stacked in this order on the substrate, and the second electrode side extracts light emission.
The first electrode is made of aluminum;
A compound in which at least one layer of the electron transport layer is represented by the following general formula (A) (excluding the case of constituting a ligand of a metal complex. The following compounds (47), (50) and (108) are also excluded ) . An organic electroluminescence device comprising at least one of the above.

[Wherein, X ₁ represents a nitrogen atom, and X _{2 to} X ₈ each represents a carbon atom. R _{2 to} R ₈ bonded to the carbon atoms of X _{2 to} X ₈ each represent a hydrogen atom or a substituent, and when there are a plurality of the substituents, they may be the same or different. R ₁ bonded to the nitrogen atom of X ₁ represents an unshared electron pair. R ₉ represents a hydrogen atom or a substituent. ]

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