An light emitting device of the present embodiments includes oppositely disposed first electrode and second electrode, and a plurality of organic layers disposed between the first electrode and the second electrode, wherein at least one among the plurality of organic layers includes a fused polycyclic compound represented by Formula 1 below, thereby showing improved emission efficiency:

##STR00001##

A metal-organic chalcogenolate (MOC) includes silver phenylselenolate functionalized with at least one functional group. The functional group may be methyl (CH.sub.3), dimethylamine (N(CH.sub.3).sub.2), thiomethyl (SCH.sub.3), fluoro (F) trifluoromethyl (CF.sub.3), cyanide (CN), carboxy (COOH), nitrito (NO.sub.2), or alkoxy (OC.sub.xH.sub.y). The MOC can be in the form of a single crystal consisting essentially of a nanocluster (0D), a nanotube (1D), or a single monolayer (2D).

An organometallic compound represented by Formula 1: ##STR00001## wherein, in Formula 1, groups and variables are the same as described in the specification.

An organic electroluminescence device of an embodiment includes a first electrode, a hole transport region on the first electrode, an emission layer on the hole transport region, an electron transport region on the emission layer, and a second electrode on the electron transport region, wherein the emission layer includes a first host compound represented by Formula 1, a second host compound represented by Formula 2, and a dopant compound comprising an organometallic complex including Pt, Au, or Cu as a central metal element, and may show improved life characteristics.

Organometallic compounds comprising an imidazole carbene ligand having a N-containing ring fused to the imidazole ring are provided. In particular, the N-containing ring fused to the imidazole ring may contain one nitrogen atom or more than one nitrogen atom. These compounds may demonstrate high photoluminescent (PL) efficiency, Gaussian emission spectra, and/or short excited state lifetimes. These materials may be especially useful as blue phosphorescent emitters.

Provided are an organic electronic element including an anode, a cathode, and an organic material layer between the anode and the cathode, and an electronic device including the organic electronic element, wherein the organic material layer includes each of the compounds represented by Formulas 1 and 2 and the driving voltage of the organic electronic element is lowered, and the luminous efficiency and lifetime of the element are improved.

Using a perovskite-type compound, an inexpensive host material having a high carrier mobility can be provided. Using a perovskite-type compound as a host material, an inexpensive organic light-emitting device having a high emission efficiency can be realized.

An organometallic compound represented by Formula 1:

M.sub.1(Ln.sub.1).sub.n1(Ln.sub.2).sub.n2  Formula 1

wherein M.sub.1 is a transition metal, Ln.sub.1 is a ligand represented by Formula 1A, Ln.sub.2 is a ligand represented by Formula 1B, n1 is 1 or 2, and n2 is 1 or 2:

##STR00001##

wherein ring CY.sub.1, ring CY.sub.2, ring CY.sub.3, X.sub.1, X.sub.2, X.sub.41, X.sub.42, R.sub.1 to R.sub.6, R.sub.10, R.sub.20, R.sub.30, R.sub.40, b10, b20, b30, and b40 are as described in the detailed description, and * and *′ each indicate a binding site to M.sub.1.

A light-emitting element having high emission efficiency is provided. A light-emitting element having a low driving voltage is provided. A novel compound which can be used for a transport layer or as a host material or a light-emitting material of a light-emitting element is provided. A novel compound with a benzofuropyrimidine skeleton is provided. Also provided is a light-emitting element which includes the compound with the benzofuropyrimidine skeleton between a pair of electrodes.

Novel host compounds consisting of carbazole and nitrile groups are disclosed. These compounds are useful in phosphorescent OLEDs.