Abstract: To provide an organic EL device having a low voltage, high efficiency and extended lifetime characteristics, and a host material for use in the organic EL device. A host material for an organic EL device, including a compound represented by the following general formula (1), or a structural isomer thereof: wherein X represents N or C—H and at least one thereof represents N, L independently represents an aromatic hydrocarbon group, and R2 to R6 represent hydrogen, an aliphatic hydrocarbon group, an aromatic hydrocarbon group, an aromatic heterocyclic group, or a linked aromatic group in which two to five of these aromatic rings are linked to each other, provided that R2 and at least one of others do not represent hydrogen.

Abstract: Provided are a material that achieves higher sensitivity and higher resolution of a photoelectric conversion element for imaging, and a photoelectric conversion element for imaging using the above material. A material for a photoelectric conversion element for imaging, the material including a compound having a structure of the following general formula (1), wherein Ar1 to Ar3 represent an aromatic hydrocarbon group, an aromatic heterocyclic group, or a linked aromatic group in which two to six of these groups are linked, and at least two groups thereof have an aromatic ring structure represented by any of the following formulae (2) to (4). X represents O or S.

Abstract: Provided are a material that achieves higher sensitivity and higher resolution of a photoelectric conversion element for imaging, and a photoelectric conversion element using the above material. A material for a photoelectric conversion element for imaging including a carbazole compound represented by (Cz)-L1-(Cz) and having a structure in which two carbazole rings (Cz) are bonded with L1, wherein at least one of L1 and a substituent Ar substituted on the carbazole rings is a group having an aromatic ring structure selected from the following formula (4) or (5). (Here, a ring A is represented by formula (5A); X1 represents O, S, Se, N—R, or N; and X2 represents O, S, or Se.

Abstract: Provided are an emission material and an organic EL device including the emission material and having high emission efficiency and a long lifetime. An emission material represented by the following general formula (1) or the like, and an organic EL device including the emission material in a light emitting layer: wherein A1 represents CR1, C or N, each ring E represents a heterocycle represented by formula (1a), X1 represents a group represented by, for example, O, S, Se, or N-L1-(Ar1)e; and a, b, c, and d represent 0 or 1, provided that, when R1 or L1 does not form a fused ring with an adjacent aromatic ring, a+b+c+d=1 is not satisfied.

Abstract: Provided are a material that achieves higher sensitivity and higher resolution of a photoelectric conversion element for imaging, and a photoelectric conversion element for imaging using the above material. A material for a photoelectric conversion element for imaging, the material having a structure of the following general formula (1), wherein L each independently represents a single bond, an aromatic hydrocarbon group having 6 to 30 carbon atoms, or the like; “a” represents the number of substitutions, and represents an integer of 1 to 6; Ar1 each independently represents a group represented by the following formula (2); and Ar2 each independently represents an aromatic heterocyclic group having 3 to 30 carbon atoms and containing a nitrogen-containing six-membered cyclic structure, or the like, provided that a group bonded to L is the aromatic heterocyclic group.

Abstract: Provided are a material that achieves higher sensitivity and higher resolution of a photoelectric conversion element for imaging, and a photoelectric conversion element for imaging using the above material. The material for a photoelectric conversion element for imaging includes an indolocarbazole compound having a pentacyclic fused-ring structure having two heteroatoms, or an analogue compound thereof. The material is a compound having, as a group bonded to a nitrogen atom or a heteroatom, an alkyl group, a substituted or non-substituted aromatic hydrocarbon group, a substituted or non-substituted ?-electron excess heteroaromatic group, or a linked aromatic group formed by linking of two to six of these aromatic groups.

Abstract: Provided is a blue light emitting organic EL device having high emission efficiency and a long lifetime. This organic EL device includes one or more light emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light emitting layers has a difference between excited singlet energy (Si) and excited triplet energy (Ti) of 0.20 eV or less and includes a light emitting dopant represented by the following formula (5), a first host selected from biscarbazole compounds, and a second host selected from N-containing 6-membered ring compounds, wherein X3 is N—Ar4, O, or S and at least one X3 is N—Ar4.

Abstract: Provided is a blue light emitting organic EL device having high emission efficiency and a long lifetime. This organic EL device includes one or more light emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light emitting layers includes a first host selected from indolocarbazole compounds, a second host selected from the compounds represented by the following general formula (2), and, as a light emitting dopant, a polycyclic aromatic compound represented by the following general formula (3) or a polycyclic aromatic compound represented by the general formula (3) as a substructure, wherein Y4 is B, P, P?O, P?S, Al, Ga, As, Si—R4 or Ge—R5, and X4 is O, N—Ar4, S or Se.

Abstract: Provided is a blue light emitting organic EL device having high emission efficiency and a long lifetime. This organic EL device comprises one or more light emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light emitting layers contains a first host, a second host, and a light emitting dopant; the first host is a carbazole compound or a bicarbazole compound; the second host is an indolocarbazole compound; and the light emitting dopant is a polycyclic aromatic compound represented by the general formula (4) or a polycyclic aromatic compound having this structure as a partial structure. In the formula, Y4 is B, P, P?O, P?S, AL, Ga, As, Si—R4, or Ge—R41, and X4 is O, N—Ar4, S, or Se.

Abstract: Provided is a blue light emitting organic EL device having high emission efficiency and a long lifetime. This organic electroluminescent device includes one or more light emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light emitting layers comprises one or more hosts selected from the indolocarbazole compounds represented by the following general formula (1) and, as a light emitting dopant, a polycyclic aromatic compound represented by the following general formula (2) or a polycyclic aromatic compound having the structure represented by the general formula (2) as a substructure, and wherein in the formulae Z is an indolocarbazole ring-containing group, X1 is O, N—Ar3, S, or Se, and Y1 is B, P, P?O, P?S, Al, Ga, As, Si—R2 or Ge—R3.

Abstract: Provided is a blue light emitting organic EL device having high emission efficiency and a long lifetime. An organic electroluminescent device comprising one or more light emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light emitting layers contains an organic emission material having a difference between excited singlet energy (S1) and excited triplet energy (T1) (?EST) of 0.20 eV or less as a light emitting dopant, a first host selected from the compounds represented by the following general formula (1), and a second host selected from the compounds represented by the following general formula (2).

Abstract: A polymer for organic electroluminescent devices having high luminous efficiency and applicable to a wet process is provided. This polymer for organic electroluminescent devices is characterized in that it includes a polymer of a polyphenylene main chain represented by General Formula (1) which is used in at least one layer of an organic layer in an organic electroluminescent device formed by laminating an anode, the organic layer, and a cathode on a substrate, and which has thermally activated delayed fluorescence characteristics (TADF characteristics) (where x is a phenylene group or a linked phenylene group, L is a single bond, an aromatic hydrocarbon group, or an aromatic heterocyclic group, and A is an aromatic hydrocarbon group, an aromatic heterocyclic group, or a linked aromatic group, and satisfies S1(A)?T1(A)?0.50 (eV)).

Abstract: Provided is a thermally activated delayed fluorescent blue light-emitting organic EL device having high luminous efficiency and a long lifetime. The organic electroluminescent device includes one or more light-emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light-emitting layers contains an indolocarbazole compound represented by the following general formula (1), which serves as a thermally activated delayed fluorescent light-emitting material, and a carbazole compound serving as a host material, and a substituent Ar2 with which a N atom in the indolocarbazole ring compound is substituted has at least one fluorine atom.