An organic light emitting display apparatus including a substrate including a plurality of pixel areas; a pixel electrode on the substrate; an opposite electrode on the pixel electrode, the opposite electrode transmitting light; an organic light emitting layer between the pixel electrode and the opposite electrode, the organic light emitting layer emitting a first light toward the opposite electrode; a light emitting layer on the opposite electrode, the light emitting layer absorbing a portion of the first light and emitting a second light; and a sealing layer on the light emitting layer, the sealing layer sealing the pixel electrode, the opposite electrode, the organic light emitting layer, and the light emitting layer.

The present disclosure relates to organic electroluminescent compounds, and a host material, an electron buffer material, an electron transport material and an organic electroluminescent device comprising the same. By using the organic electroluminescent compounds of the present disclosure, the organic electroluminescent device secures fast electron current properties by intermolecular stacking and interaction, and thus, it is possible to provide the organic electroluminescent device having low driving voltage and/or excellent luminous efficiency and/or efficient lifespan properties.

An organic light-emitting device having improved efficiency and lifespan includes: a first electrode, a second electrode, and an organic layer between the first electrode and the second electrode, wherein the organic layer includes an emission layer, the emission layer includes a first compound, a second compound, 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 includes a metal element having an atomic number of 40 or more, the fourth compound includes boron (B), the third compound and the fourth compound each satisfy Conditions 1-1 and 1-2 below, and the fourth compound satisfies Condition 2 or 3:
T.sub.1(C3).sub.onset≥S.sub.1(C4).sub.onset  Condition 1-1
T.sub.1(C3).sub.max≥S.sub.1(C4).sub.max  Condition 1-2
K.sub.RISC(C4)≥10.sup.3S.sup.−1  Condition 2
f(C4)≥0.1.  Condition 3

An organic electroluminescence device may include a first electrode, a second electrode opposite to the first electrode, and organic layers disposed between the first electrode and the second electrode. At least one of organic layers may include an organometallic complex including a first metal complex having a metal atom as a center atom of the first metal complex, a second metal complex having the metal atom as a center atom of the second metal complex, and an aromatic ring group connecting the first metal complex to the second metal complex.

A heteroacene having the following formula (F) is described. An organic electroluminescence device comprises the heteroacene as a phosphorescent host, a fluorescent host, a hole blocking layer, or an electron transport layer. The heteroacene lowers a driving voltage, or increases a current efficiency or a half-life of the organic electroluminescence device. ##STR00001##

An organic electroluminescence device includes an emitting region provided between an anode and a cathode, in which the emitting region includes a first emitting layer and a second emitting layer, a ratio D.sub.EM1/D.sub.EM2 of a film thickness of the first emitting layer D.sub.EM1 to a film thickness of the second emitting layer D.sub.EM2 is in a range from 2/3 to 3/2, the first emitting layer contains a first host material and a first emitting compound, the second emitting layer contains a second host material and a second emitting compound, and the first host material has a group represented by a formula (10) below and is a compound represented by a formula (1) below. ##STR00001##

The present application provides a heterocyclic compound capable of significantly enhancing lifetime, efficiency, electrochemical stability and thermal stability of an organic light emitting device, and an organic light emitting device including the heterocyclic compound in an organic material layer.

Provided is an organic light emitting device comprising an anode, a hole transport layer, a light emitting layer, an electron transport layer, and a cathode, wherein the light emitting layer comprises a compound of Chemical Formula 1 and a compound of Chemical Formula 2:

##STR00001##

wherein: A is a benzene ring; Ar.sub.1 and Ar.sub.2 are independently a substituted or unsubstituted C.sub.6-60 aryl or C.sub.2-60 heteroaryl containing one or more of N, O and S; X.sub.1 to X.sub.3 are independently N or CH, provided that at least one of them is N; L is a substituted or unsubstituted C.sub.2-60 heteroarylene or a C.sub.6-60 arylene substituted with a C.sub.2-20 heteroaryl, the heteroarylene or heteroaryl containing one or more of N, O and S; and Ar.sub.3 and Ar.sub.4 are independently a substituted or unsubstituted C.sub.6-60 aryl or C.sub.2-60 heteroaryl containing one or more of N, O and S.

An organic electroluminescence device includes two or more emitting units disposed between an anode and a cathode, and an intermediate layer, in which the intermediate layer contains a phenanthroline compound, the laminated emitting unit includes a first emitting layer containing a first host material and a second emitting layer containing a second host material, and a triplet energy T.sub.1(H1) of the first host material and a triplet energy T.sub.1(H2) of the second host material satisfy a relationship of a numerical formula (Numerical Formula 3),

T.sub.1(H1)>T.sub.1(H2)  (Numerical Formula 3).

Provided are an organic electroluminescent material and a device thereof. The organic electroluminescent material is a metal complex comprising a ligand L.sub.a having a structure of Formula 1. The metal complex may be used as a light-emitting material in an electroluminescent device. These novel compounds may be applied to electroluminescent devices and can exhibit better performance, achieve higher device efficiency, and significantly improve the overall performance of the devices. Further provided are an electroluminescent device comprising the metal complex and a compound combination comprising the metal complex.