An organic electroluminescence device includes an anode, an emitting layer, and a cathode in this order. The emitting layer comprises a delayed fluorescent compound M2 and a compound M3 having at least one deuterium atom, and the compound M3 is not a compound having a partial structure represented by a formula (1C) or (2C). S.sub.1(M2) of the compound M2 and S.sub.1(M3) of the compound M3 satisfy a relationship of S.sub.1(M3)>S.sub.1(M2). In the formulae (1C) and (2C), Y.sub.41 to Y.sub.48 are each independently a N atom, CR, or a C atom bonded to another atom or the like in the compound M3, where each R is independently a H atom or a substituent, at least one of Y.sub.41 to Y.sub.48 is a N atom, and at least one of Y.sub.41 to Y.sub.48 is a C atom bonded to another atom or the like in the compound M3.

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An organic electroluminescence device includes: an anode; a cathode; and an emitting layer provided between the anode and the cathode, in which the emitting layer contains a delayed fluorescent compound M2 and a compound M3 represented by a formula (3) and a singlet energy S.sub.1(M2) of the compound M2 and a singlet energy S.sub.1(M3) of the compound M3 satisfy a relationship of a numerical formula (Numerical Formula 1) below, S.sub.1(M3)>S.sub.1(M2) . . . (Numerical Formula 1). In the formula (3), A3 is a group represented by a formula (3a) or the like.

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A photoelectric conversion element includes a first electrode, a second electrode, a photoelectric conversion layer positioned between the first electrode and the second electrode and including a donor semiconductor material and an acceptor semiconductor material, and a first charge blocking layer positioned between the first electrode and the photoelectric conversion layer. The first charge blocking layer includes a first material and a second material having an energy band gap narrower than that of the first material. The electron affinity of the first material is lower than that of the second material, and the ionization potential of the first material is higher than that of the second material.

An organometallic compound represented by Formula 1 emits deep blue light. A light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device may have excellent or suitable driving voltage, luminescence efficiency, color conversion efficiency, and/or lifespan characteristics:

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In Formula 1, X.sub.1 to X.sub.4 are each independently C or N, Y.sub.11 is C(Z.sub.11) or N, and Y.sub.12 is C(Z.sub.12) or N.

Provided is an organic light-emitting element that is excited by an electromagnetic wave. The organic light-emitting element includes: a first electrode; a second electrode disposed to face the first electrode; an organic light-emitting layer disposed between the first electrode and the second electrode, where separation of charges occurs due to incidence of the electromagnetic wave; a hole transporting layer disposed between the first electrode and the organic light-emitting layer; and a charge block layer disposed between the second electrode and the organic light-emitting layer. The charge block layer has a LUMO level shallower than a LUMO level of organic light emitters included in the organic light-emitting layer.

An electroluminescent device comprising a first electrode and a second electrode facing each other, an emission layer disposed between the first electrode and the second electrode and including at least two light emitting particles, a hole transport layer disposed between the first electrode and the emission layer, and an electron transport layer disposed between the emission layer and the second electrode, wherein the electron transport layer comprises an inorganic layer disposed on the emission layer, the inorganic layer comprising a plurality of inorganic nanoparticles; and an organic layer directly disposed on at least a portion of the inorganic layer on a side opposite the emission layer, wherein a work function of the organic layer is greater than a work function of the inorganic layer.

An organic light-emitting device and display apparatus, the device including a first electrode; a second electrode facing the first electrode; an emission layer between the first and second electrode; a hole control layer between the first electrode and the emission layer; and an electron control layer between the emission layer and the second electrode, wherein the emission layer includes a plurality of sub-emission layers to emit light having different wavelengths, at least portions of the plurality of sub-emission layers do not overlap one another, the plurality of sub-emission layers include: a first sub-emission layer including a first color light-emitting dopant, and a second sub-emission layer including a second color light-emitting dopant, the first and second sub-emission layers each include a hole-transporting and electron-transporting host which form an exciplex, and a triplet energy of the exciplex is equal to or greater than triplet energies of the first and second color light-emitting dopant.

A heterocyclic compound represented by Chemical Formula 1 and an organic light emitting device including the same, and the heterocyclic compound which is used as a material of an organic material layer of the organic light emitting device and provides improved efficiency, low driving voltage and improved lifetime characteristics of the organic light emitting device.

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Provided is a compound that can improve the luminous efficiency, stability and life span of the element, an organic electronic element using the same, and an electronic device thereof.

Provided are a composition for an organic optoelectronic device including a first compound represented by Chemical Formula 1 and a second compound represented by Chemical Formula 2, an organic optoelectronic device including the same, and a display device. Details of Chemical Formula 1 and Chemical Formula 2 are as defined in the specification.