A light emitting diode of an embodiment includes a first electrode, a second electrode, and at least one functional layer disposed between the first electrode and the second electrode, wherein the at least one functional layer includes a polycyclic compound represented by Formula A or Formula B, thereby showing high emission efficiency properties and improved life characteristics.

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A light-emitting device including: m emitting units located between a first electrode and a second electrode; and m−1 charge generation units, each located between two neighboring emitting units among the m emitting units and including an n-type charge generation layer and a p-type charge generation layer. The m emitting units may each include an emission layer, at least one of the m emission layers comprises a first emission layer and a second emission layer that are in contact with each other, the first emission layer includes a first host, a second host, and a first dopant, the second emission layer includes a third host, a fourth host, and a second dopant, the first host and the second host form a first exciplex, the third host and the fourth host form a second exciplex, and the first dopant is a delayed fluorescence dopant, and the second dopant is a phosphorescent dopant.

Provided are a condensed cyclic compound represented by one of Formulae 1 to 4, an organic light-emitting device including the condensed cyclic compound, and an electronic apparatus including the organic light-emitting device:

##STR00001## Formulae 1 to 4 may respectively be understood by referring to the descriptions Formulae 1 to 4 provided herein.

Provided are a condensed cyclic compound represented by Formula 1, an organic light-emitting device including the same, and an electronic apparatus including the organic light-emitting device.

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The detailed description of Formula 1 is the same as described in the present specification.

A light emitting device includes a first electrode, a second electrode disposed on the first electrode, and a light emitting layer disposed between the first electrode and the second electrode. The light emitting layer includes a novel polycyclic compound and thus, the light emitting device may exhibit high light emission efficiency properties and improved lifespan properties.

A compound has, in a molecule, a cyclic structure represented by a formula (1) below; and at least one cyclic structure selected from the group consisting of a cyclic structure represented by a formula (10) below and a cyclic structure represented by a formula (11) below. In the formula (1): R.sub.1 to R.sub.16 are each independently a hydrogen atom, an alkyl group or the like; and R.sub.X and R.sub.Y are each independently an alkyl group.

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A semiconductor photoelectrode that is to be located in an aqueous solution to cause a decomposition reaction of the aqueous solution upon being irradiated with light, the semiconductor photoelectrode including: a semiconductor layer that is formed on an insulative or conductive substrate and is provided with a plurality of protrusion structures that protrude in one direction that is opposite a direction in which the substrate is located; a catalyst layer that is continuously laminated on the surface of the semiconductor layer; and a wire that is electrically connected to the semiconductor layer.

Provided is a compound including a first ligand L.sub.A of Formula I

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In Formula I, ring C is a 5- or 6-membered ring; each of X.sup.1 to X.sup.8 is C or N; one of X.sup.1 to X.sup.4 is C and is connected to ring C, and one of X.sup.1 to X.sup.4 is N and is coordinated to a metal M; Y is a divalent linker; K is a direct bond, O, or S; each R′, R″, R.sup.A, R.sup.B, and R.sup.C is hydrogen or a general substituent; at least one of R.sup.A or R.sup.B comprises an electron-withdrawing group; at least one of R.sup.B is a cyclic group; and metal M is selected from Os, Ir, Pd, Pt, Cu, Ag, and Au. Formulations, devices, and consumer products comprising the compound are also disclosed.

An organoelectroluminescent device according to the present invention employs compounds of characteristic structures as a hole transport material and a dopant material in a hole injection layer or a hole transport layer, and in an emissive layer, respectively, and thus can be driven at a low voltage and realize highly efficient emission characteristics with excellent external quantum efficiency. Thus, the organoelectroluminescent device may be industrially advantageously used in a flexible display device, a flexible display device, a single-color or white-color flat lighting device, a single-color or shite-color flexible lighting device, and the like.

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 Y.sup.4 is B, P, P═O, P═S, Al, Ga, As, Si—R.sup.4 or Ge—R.sup.5, and X.sup.4 is O, N—Ar.sup.4, S or Se.

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