A composition including a first compound and a second compound, wherein the first compound is an organometallic compound including platinum and a tetradentate ligand bound thereto, and the second compound is an organometallic compound including iridium, μ(Pt) is about 0.5 debye to about 5.0 debye, μ(Pt) is less than μ(Ir), μ(Pt) is a dipole moment of the first compound, μ(Ir) is a dipole moment of the second compound, and each of μ(Pt) and μ(Ir) is calculated based on density functional theory as described herein.

A light-emitting device with high resistance to heat in a fabrication process is provided. The light-emitting device includes an EL layer between an anode and a cathode. The EL layer includes at least a light-emitting layer and an electron-transport layer that includes a first electron-transport layer in contact with the light-emitting layer and a second electron-transport layer in contact with the first electron-transport layer. The first electron-transport layer includes a first heteroaromatic compound including at least one heteroaromatic ring. The second electron-transport layer includes a second heteroaromatic compound that includes at least one heteroaromatic ring and is different from the first heteroaromatic compound. The first heteroaromatic compound has a difference of 20° C. or less between the crystallization temperature (Tpc) of a powder state and the crystallization temperature (Ttc) of a thin film state. The second heteroaromatic compound has a difference of 100° C. or less between Tpc and Ttc.

A display apparatus that includes an OLED (organic light-emitting device) substrate including a first blue light-emitting unit, a green light-emitting unit, and a second blue light-emitting unit which are stacked; and a color controller provided on the OLED substrate to adjust color of a light generated from the OLED substrate.

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 element includes a first electrode, a second electrode disposed on the first electrode, and an emission layer disposed between the first electrode and the second electrode. The emission layer may include a first compound represented by Formula 1, and at least one of a second compound, a third compound, and a fourth compound. The light emitting element including the first compound represented by Formula 1 exhibits high efficiency and a long lifespan.

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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.

Tridentate platinum, palladium, and gold complexes of Formulas A-I and A-II and tridentate iridium and rhodium compounds of Formulas B-I, B-II, and B-III suitable for delayed fluorescent and phosphorescent or phosphorescent emitters in display and lighting applications.

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A light-emitting device including a first electrode, a hole transport region disposed on the first electrode, a first light-emitting layer disposed on the hole transport region and emitting light of a first wavelength, a second light-emitting layer disposed on the hole transport region and emitting light of a second wavelength different from the first wavelength, an electron transport region disposed on the first light-emitting layer and the second light-emitting layer, and a second electrode disposed on the electron transport region, wherein the second light-emitting layer includes a first sub light-emitting layer including a first host and a first dopant and emitting the light of the second wavelength, and a second sub light-emitting layer including a second host different from the first host and a second dopant and emitting the light of the second wavelength. Accordingly, a luminous efficiency and device lifetime of the light-emitting device may be improved.

An organic light-emitting device including a first electrode, a second electrode facing the first electrode, and an organic layer disposed between the first electrode and the second electrode, wherein the organic layer includes an emission layer, wherein the emission layer includes an electron transport host, a hole transport host, and a dopant, wherein the dopant includes an organometallic compound, and wherein the organometallic compound does not comprise iridium, wherein the organic light-emitting device satisfies predetermined parameters described in the specification.