An organic electroluminescence device includes: an anode; an emitting layer; and a cathode, the emitting layer containing a first material, a second material and a third material, the first material being a fluorescent material, the second material being a delayed fluorescent material, the third material having a singlet energy larger than a singlet energy of the second material.

A composition of materials including a first compound having a structure according to Formula I

##STR00001##

To provide a practically useful organic electroluminescent device which is improved in luminous efficiency and at the same time, sufficiently secures the stability during driving. An organic electroluminescent device, wherein a light-emitting layer includes two host materials different from each other, and a dopant material, one of the host materials is a compound represented by general formula (1) and the other of the host materials is a compound represented by general formula (2). A ring A is a heterocycle represented by formula (1a), X represents N or C—Ar′, Y represents O, S, N—Ar.sup.3, or C—Ar.sup.4Ar.sup.5, and any one of Z.sup.1 to Z.sup.4 represents a carbon atom binding to a 6-membered ring containing X and the others and Z.sup.5 to Z.sup.8 each represent C—Ar′ or N. Ar, Ar′ and Ar.sup.1 to Ar.sup.5 each represent, for example, hydrogen, or an alkyl group having 1 to 20 carbon atoms. A ring B is a heterocycle represented by formula (2a), and Ar.sup.6 and Ar.sup.7 each represent, for example, hydrogen, or an alkyl group having 1 to 20 carbon atoms.

Novel compounds comprising heteroleptic iridium complexes are provided. The compounds have a particular combination of ligands which includes a single pyridyl dibenzo-substituted ligand. The compounds may be used in organic light emitting devices, particularly as emitting dopants, to provide devices having improved efficiency, lifetime, and manufacturing.

The present disclosure relates in part to compounds capable of emitting delayed fluorescence and uses of these compounds in organic light-emitting diodes.

A condensed cyclic compound represented by Formula 1:

##STR00001## wherein in Formula 1, Ar and R.sub.1 to R.sub.8 are the same as described in the specification.

The present invention relates to an imidazopyridine-based arylamine compound and an application thereof. The compound has a structure as shown in Formula I. The compound of the present invention has the advantages such as, a low sublimation temperature, a good thermal stability, a high refractive index, and a small refractive index difference in the visible light region, and can be used as a light extraction layer material for use in an organic light-emitting device.

##STR00001##

To provide an organic electroluminescent device having high efficiency while having a driving voltage. This organic electroluminescent device includes an anode, an organic layer and a cathode stacked on a substrate, at least one layer of the organic layer is a light-emitting layer containing a first host, a second host and a light-emitting dopant material, the first host is selected from a compound represented by the following general formula (1), and the second host is selected from a biscarbazole compound binding at a position other than the N-position, an indolocarbazole compound, or a carbazole compound in which a plurality of carbazole rings bind at the N-position. In the formula, a ring A is represented by formula (1b) or (1c), X represents NR, S, O, or CR.sub.2, and at least one Y represents N.

Provided are a compound of Formula 1 and an organic electric element including a first electrode, a second electrode, and an organic material layer between the first electrode and the second electrode and comprising the compound, the element showing improved luminescence efficiency, stability, and life span.

An organometallic compound, represented by Formula 1:

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

wherein, in Formula 1, 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 the substituents of Formulae 1A and 1B are as provided herein in the detailed description.