Abstract: Provided is a thermally activated delayed fluorescent organic electroluminescent device having a low driving voltage, high luminous efficiency, and a long lifetime. The organic electroluminescent device includes light-emitting layers between an anode and a cathode opposite to each other, and at least one of the light-emitting layers contains a thermally activated delayed fluorescent material, or the thermally activated delayed fluorescent material and a host material. The thermally activated delayed fluorescent material is represented by the following general formula (1) where A represents an electron-withdrawing group, such as a CN group, and D1 and D2 each represent an electron-donating group having an indole ring structure.

Abstract: To provide an organic electroluminescent device having long lifetime characteristics while having a low driving voltage and high power efficiency. The organic electroluminescent device includes one or more light-emitting layers between an anode and a cathode opposed to each other, wherein at least one of the light-emitting layers contains a host material including a first host material, a second host material and a third host material, and a light-emitting dopant material. A LUMO energy of the first host material is ?1.95 eV or less, and LM2?LM3?LM1 is satisfied under the assumption that LUMO energies of the first host material, the second host material and the third host material are LM1, LM2 and LM3, respectively.

Abstract: Provided is an organic EL device having high efficiency and high driving stability while being driven at a low voltage. The organic electroluminescent device includes one or more light-emitting layers between an anode and a cathode opposite to each other. At least one of the light-emitting layers contains a host material and a light-emitting dopant, and (i) a first host formed of an indolocarbazole compound having one or two indolocarbazole rings, and (ii) a second host formed of a carbazole compound having a plurality of carbazole rings and having a bond structure represented by the following general formula (3) are used as the host material.

Abstract: Provided is a thermally activated delayed fluorescence-emitting organic EL element having a low driving voltage, high luminous efficiency, and a prolonged lifespan. The organic EL element contains one or more light-emitting layers between an anode and a cathode that face each other, and at least one light-emitting layer contains a host material composed of a carbazole compound represented by formula (1) and a thermally activated delayed fluorescence material composed of an indolocarbazole compound containing an indolocarbazole ring in its molecule. Here, L1 represents an aromatic group, and at least one R1 represents a carbazolyl group, and n is 1 or 2.

Abstract: Provided is an organic electroluminescence device (organic EL device) that is driven at a low voltage, exhibits high luminous efficiency and has a long service life. The organic EL device contains one or more light emitting layers and one or more electron transport layers between opposing anode and cathode, wherein at least one of the electron transport layers contains a an indolocarbazole compound represented by general formula (1) below and an electron donor. In the formula, ring A represents an aromatic hydrocarbon ring represented by formula (1a), ring B represents a heterocyclic ring represented by formula (1b), L represents a single bond or aromatic hydrocarbon group, X represents N or C—Ar1 and at least one of X represents N, and Y and Ar1 represent a hydrogen atom, aromatic hydrocarbon group or aromatic heterocyclic group.

Abstract: Provided is a thermally activated delayed fluorescence-emitting organic EL element having a low driving voltage, high luminous efficiency, and a prolonged lifespan. The organic EL element contains one or more light-emitting layers between an anode and a cathode that face each other, and at least one light-emitting layer contains a host material composed of a carbazole compound represented by formula (1) and a thermally activated delayed fluorescence material composed of an indolocarbazole compound containing an indolocarbazole ring in its molecule. Here, L1 represents an aromatic group, and at least one R1 represents a carbazolyl group, and n is 1 or 2.

Abstract: Provided is a practically useful organic EL element having high efficiency and high driving stability while being capable of being driven at a low voltage. The organic EL element has a light-emitting layer and any other organic layer between an anode and a cathode opposite to each other. The light-emitting layer contains at least two host materials and at least one light-emitting dopant. At least one of the host materials is a host material selected from compounds each having one or two indolocarbazole skeletons, and at least one of the other host materials is a host material selected from carbazole compounds each substituted with a dibenzofuran or a dibenzothiophene.

Abstract: Provided is a practically useful organic electroluminescent device (organic EL device) having high efficiency and high driving stability while being capable of being driven at a low voltage. The organic electroluminescent device includes a light-emitting layer between an anode and a cathode opposite to each other. The light-emitting layer contains two host materials and at least one light-emitting dopant. One of the two host materials is a host material selected from an indolocarbazole compound having one indolocarbazole ring and an indolocarbazole compound having two indolocarbazole rings, and the other thereof is a host material selected from carbazole compounds.

Abstract: Provided is an organic electroluminescence device (organic EL device) that is driven at a low voltage, exhibits high luminous efficiency and has a long service life. The organic EL device contains one or more light emitting layers and one or more electron transport layers between opposing anode and cathode, wherein at least one of the electron transport layers contains a an indolocarbazole compound represented by general formula (1) below and an electron donor. In the formula, ring A represents an aromatic hydrocarbon ring represented by formula (1a), ring B represents a heterocyclic ring represented by formula (1b), L represents a single bond or aromatic hydrocarbon group, X represents N or C—Ar1 and at least one of X represents N, and Y and Ar1 represent a hydrogen atom, aromatic hydrocarbon group or aromatic heterocyclic group.

Abstract: Provided is a thermally activated delayed fluorescent organic electroluminescent device having a low driving voltage, high luminous efficiency, and a long lifetime. The organic electroluminescent device includes light-emitting layers between an anode and a cathode opposite to each other, and at least one of the light-emitting layers contains a thermally activated delayed fluorescent material, or the thermally activated delayed fluorescent material and a host material. The thermally activated delayed fluorescent material is represented by the following general formula (1) where A represents an electron-withdrawing group, such as a CN group, and D1 and D2 each represent an electron-donating group having an indole ring structure.

Abstract: Provided is an organic electroluminescent device having high efficiency and high driving stability while being driven at a low voltage. The organic electroluminescent device is an organic electroluminescent device including a light-emitting layer between an anode and a cathode opposite to each other, in which: the light-emitting layer contains two kinds of host materials and a light-emitting dopant; and a first host material (H1) out of the two kinds of host materials is an indolocarbazole-based compound having one or two indolocarbazole rings, and a second host material (H2) out of the materials is a host material selected from carbazole-based compounds each represented by the general formula (3), the compounds each having a structure in which two carbazole rings are bonded through a six-membered aromatic ring.

Abstract: Provided is an organic EL device having a low driving voltage, high luminous efficiency, and a long lifetime. The organic EL device is an organic electroluminescent device including a light-emitting layer between an anode and a cathode opposite to each other, in which: the light-emitting layer contains a host material and a light-emitting dopant material; and the host material is a material obtained by mixing a first host selected from compounds in each of which a diphenyltriazinyl group is bonded to one nitrogen atom of an indolocarbazole ring and a phenyl group of the diphenyltriazinyl group is substituted with one or more phenyl groups, and a second host selected from compounds in each of which aromatic hydrocarbon groups are bonded to two nitrogen atoms of a biscarbazole ring and at least one of the aromatic hydrocarbon groups is a fused aromatic hydrocarbon group.

Abstract: Provided is an organic EL device having high efficiency and high driving stability while being driven at a low voltage. The organic electroluminescent device includes one or more light-emitting layers between an anode and a cathode opposite to each other. At least one of the light-emitting layers contains a host material and a light-emitting dopant, and (i) a first host formed of an indolocarbazole compound having one or two indolocarbazole rings, and (ii) a second host formed of a carbazole compound having a plurality of carbazole rings and having a bond structure represented by the following general formula (3) are used as the host material.

Abstract: Provided is a homogeneous organic EL device having a low driving voltage, high luminous efficiency, and a long lifetime. The device is an organic electroluminescent device including a light-emitting layer between an anode and a cathode opposite to each other, in which: the light-emitting layer contains a host material and a light-emitting dopant material; the host material is a material obtained by preliminarily mixing two or more kinds of compounds selected from compounds each having a structure in which two nitrogen atoms of an indolocarbazole ring are each substituted with an aromatic hydrocarbon group or an aromatic heterocyclic group; and the light-emitting layer is formed by co-depositing the preliminarily mixed host material and the light-emitting dopant material in a vacuum.

Abstract: Provided is a practically useful organic EL element having high efficiency and high driving stability while being capable of being driven at a low voltage. The organic EL element has a light-emitting layer and any other organic layer between an anode and a cathode opposite to each other. The light-emitting layer contains at least two host materials and at least one light-emitting dopant. At least one of the host materials is a host material selected from compounds each having one or two indolocarbazole skeletons, and at least one of the other host materials is a host material selected from carbazole compounds each substituted with a dibenzofuran or a dibenzothiophene.

Abstract: Provided is a practically useful organic electroluminescent device (organic EL device) having high efficiency and high driving stability while being capable of being driven at a low voltage. The organic electroluminescent device includes a light-emitting layer between an anode and a cathode opposite to each other. The light-emitting layer contains two host materials and at least one light-emitting dopant. One of the two host materials is a host material selected from an indolocarbazole compound having one indolocarbazole ring and an indolocarbazole compound having two indolocarbazole rings, and the other thereof is a host material selected from carbazole compounds.

Abstract: Disclosed is an organic electroluminescent device (organic EL device) which can achieve high efficiency and long lifetime even when driven at low voltage. The organic El device comprises at least a light-emitting layer and an electron-transporting layer between an anode and a cathode facing each other. The electron-transporting layer consists of two layers, namely, a first electron-transporting layer and a second electron-transporting layer and the first electron-transporting layer and the second electron-transporting layer are arranged sequentially in this order from the light-emitting layer side to the cathode side. The first electron-transporting layer contains an indole derivative in which the ring nitrogen atom is substituted with an aromatic group and an aromatic ring is fused to the indole ring.

Abstract: Disclosed are a compound for an organic electroluminescent device (organic EL device) which is improved in luminous efficiency, fully secured of driving stability, and of simple constitution and an organic EL device using said compound. The compound for an organic EL device has two indolocarbazole skeletons each of which is bonded to an aromatic group or two skeletons similar thereto. The organic EL device comprises a light-emitting layer disposed between an anode and a cathode piled one upon another on a substrate and said light-emitting layer comprises a phosphorescent dopant and the aforementioned compound for an organic EL device as a host material.

Abstract: Disclosed are an organic electroluminescent device (organic EL device) which is improved in luminous efficiency, fully secured of driving stability, and of simple constitution and a compound useful for the fabrication of said organic EL device. The compound for the organic EL device has an indolocarbazole structure or a structure similar thereto in the molecule wherein an aromatic group is bonded to the nitrogen atom in the indolocarbazole. The organic EL device has a light-emitting layer disposed between an anode and a cathode piled one upon another on a substrate and said light-emitting layer comprises a phosphorescent dopant and the aforementioned compound for an organic electroluminescent device as a host material.

Abstract: Disclosed is an organic electroluminescent device (organic EL device) that utilizes phosphorescence and is improved in luminous efficiency and fully secured of driving stability. The organic EL device comprises an anode, an organic layer containing a hole-transporting layer, a light-emitting layer, and an electron-transporting layer, and a cathode piled one upon another on a substrate while the hole-transporting layer is disposed between the light-emitting layer and the anode and the electron-transporting layer is disposed between the light-emitting layer and the cathode. The light-emitting layer comprises an aluminum heterocomplex or dimeric complex of deuterated substituted or unsubstituted 2-methyl-8-hydroxyquinoline (Me8HQ-D) in which the hydrogen atoms in the methyl group of substituted or unsubstituted 2-methyl-8-hydroxyquinoline (Me8HQ) are deuterated as a host material and an organic metal complex containing at least one metal selected from groups 7 to 11 of the periodic table as a guest material.