An organic light-emitting device includes: an anode, an emitting layer, and a cathode that are stacked; a first functional material layer located between the emitting layer and the anode; and a second functional material layer located between the emitting layer and the cathode. Under a same test condition, a hole mobility of a material of the first functional material layer is at least ten times an electron mobility of a material of the second functional material layer.

This composition for a hole collecting layer of an organic photoelectric conversion element contains: a charge-transporting substance comprising a polyaniline derivative represented by formula (1); a fluorine-based surfactant; and a solvent. The composition provides a thin film suitable for a hole collecting layer of an organic photoelectric conversion element, and is particularly suited for producing an inverse lamination type organic photoelectric conversion element. ##STR00001##
(In the formula, R.sup.1 to R.sup.6 each independently represent a hydrogen atom, etc., but one of R.sup.1 to R.sup.4 is a sulfonic acid group, one or more of the remaining R.sup.1 to R.sup.4 are a C1-20 alkoxy group, a C1-20 thioalkoxy group, a C1-20 alkyl group, a C2-20 alkenyl group, a C2-20 alkynyl group, a C1-20 haloalkyl group, a C6-20 aryl group, or a C7-20 aralkyl group, and m and n are numbers which satisfy 0≤m≤1, 0≤n≤1 and m+n=1).

A light emitting device that includes a first electrode, a second electrode oppositely disposed to the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes an organometallic compound represented by Formula 1:

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A light emitting device that includes a first electrode, a second electrode oppositely disposed to the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes an organometallic compound represented by Formula 1:

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A nitrogen-containing compound is represented by the following Formula 1 ##STR00001##
where B.sub.1 to B.sub.4 are each independently N or CR.sub.1, A.sub.1 is an electron accepting group, L1 and R1 are further defined, and D is an electron donating group represented by the following Formula 2 ##STR00002##
X is Si or Ge and Y1, Y2, R2, R3, n and m are further defined. An organic electroluminescence device includes the nitrogen-containing compound.

A light emitting element that includes a first electrode, a second electrode on the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes an organometallic compound represented by Formula 1. The light emitting element exhibits long lifespan properties.

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A light emitting element that includes a first electrode, a second electrode on the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes an organometallic compound represented by Formula 1. The light emitting element exhibits long lifespan properties.

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Provided is a light-emitting device which may include 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 emission layer includes a host and a dopant, the host includes a first compound and a second compound, the dopant includes a third compound and a fourth compound, the first compound, the second compound, the third compound, and the fourth compound are different from each other, the third compound is a platinum-containing organometallic compound, the platinum-containing organometallic compound includes platinum and a first ligand bonded to the platinum, the first ligand includes a carbene group, the carbon of the carbene group and the platinum are bonded together, and Expression 1 is satisfied, which is explained in the specification.

Provided is a light-emitting device which may include 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 emission layer includes a host and a dopant, the host includes a first compound and a second compound, the dopant includes a third compound and a fourth compound, the first compound, the second compound, the third compound, and the fourth compound are different from each other, the third compound is a platinum-containing organometallic compound, the platinum-containing organometallic compound includes platinum and a first ligand bonded to the platinum, the first ligand includes a carbene group, the carbon of the carbene group and the platinum are bonded together, and Expression 1 is satisfied, which is explained in the specification.

A light emitting element that includes a first electrode, a second electrode facing the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes a polycyclic compound represented by Formula 1. The light emitting element has a reduced driving voltage and an increased efficiency.

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