An organic EL device includes a first emitting layer and a second emitting layer, in which the first emitting layer contains a first host material, the second emitting layer contains a second host material, the first and the second host material are mutually different, the first emitting layer and the second emitting layer at least contains a compound that emits fluorescence having a main peak wavelength of 500 nm or less, respectively, the compound contained in the first emitting layer and that emits fluorescence having a main peak wavelength of 500 nm or less is the same as or different from the compound contained in the second emitting layer, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a numerical formula (Numerical Formula 1),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 1).

An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer includes, as a first host material, a first compound that includes at least one group represented by a formula (11) below, the first compound being represented by a formula (1) below, the second emitting layer includes a second compound represented by a formula (2A) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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An organic electroluminescence device includes an anode, a cathode, a first emitting layer, and a second emitting layer provided between the first emitting layer and the cathode, in which the first emitting layer contains a first compound represented by a formula (101) below as a first host material, the second emitting layer contains a second compound represented by a formula (2) below as a second host material, and the first emitting layer is in direct contact with the second emitting layer.

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To provide an organic electroluminescent device having high efficiency and high driving stability while having a low driving voltage. The organic electroluminescent device has 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 is a light-emitting layer composed of a vapor deposition layer containing a first host, a second host and a light-emitting dopant material; the first host is selected from oligopyridine compounds represented by the general formula (1); and the second host is selected from carbazole compounds having two or more carbazole rings, indolocarbazole compounds having an indolocarbazole ring or compounds having a carbazole ring and an indolocarbazole ring.

The present disclosure relates to compounds of Formula I) as useful materials for OLED's. X.sup.1, X.sup.2 and X.sup.3 are N or C(R.sup.5); Ar.sup.1 and Ar.sup.2 are aryl, heteroaryl or cyano; L.sup.1 is single bond, arylene or heteroarylene; and R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are diarylamino, carbazolyl, heteroaryl, H or alkyl.

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The present disclosure relates to compounds capable of emitting delayed fluorescence, and uses of the compounds in organic light-emitting diodes.

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer, wherein the interlayer includes a heterocyclic compound of Formula 1:

A.sub.1B.sub.1].sub.n1  Formula 1

wherein, in Formula 1, the variables are defined herein.

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode, wherein the interlayer includes an emission layer and an electron transport region, the electron transport region is between the emission layer and the second electrode, the electron transport region includes a first compound of Formula 1, an alkali metal halide, and a lanthanide metal, and the first compound includes one or more C.sub.8-C.sub.60 carbocyclic groups or a C.sub.8-C.sub.60 heterocyclic group, wherein, in Formula 1, the variables are defined herein.

Provided is the nitrogen-containing compound shown in Chemical formula 1, an organic electroluminescent device, and an electronic apparatus, relating to the technical field of organic materials. The nitrogen-containing compound can improve the performance of the organic electroluminescent device. ##STR00001##

Organic photovoltaic cells (OPVs) and their compositions are described herein. In one or more embodiments, the acceptor with an active layer of an OPV includes is a non-fullerene acceptor. Such non-fullerene acceptors may provide improved OPV performance characteristics such as improved power conversion efficiency, open circuit voltage, fill factor, short circuit current, and/or external quantum efficiency. One example of a non-fullerene acceptor is (4,4,10,10-tetrakis(4-hexylphenyl)-5,11-(2-ethylhexyloxy)-4,10-dihydro-dithienyl[1,2-b:4,5b′] benzodi-thiophene-2,8-diyl) bis(2-(3-oxo-2,3-dihydroinden-5,6-dichloro-1-ylidene) malononitrile.