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

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.

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.

Provided is a light-emitting material having a polycyclic ligand. The light-emitting material is a novel metal complex comprising a polycyclic ligand having a structure of Formula 1 and may be used as light-emitting material in an electroluminescent device. These novel metal complexes can greatly red-shift the maximum emission wavelengths of electroluminescent devices and significantly adjust emitting colors of the devices and have very narrow emission spectra and can greatly improve the luminescence saturation of the devices and provide better device performance. Further provided are an electroluminescent device and a compound combination.

Provided is an electroluminescent device. The organic electroluminescent device comprises an anode, a cathode and an organic layer disposed between the anode and the cathode, where the organic layer comprises a first compound having a structure of H-L.sub.1-E and a second compound having a general formula of M(L.sub.a).sub.m(L.sub.b).sub.n(L.sub.c).sub.q, and the device has at least one maximum emission wavelength greater than 630 nm. Such a new material composition consisting of the first compound and the second compound can be used in a light-emitting layer of the electroluminescent device. The new material composition can achieve the emission of deep red light in the device, significantly reduce a drive voltage of the device while significantly improving device efficiency and/or a device lifetime, and provide better device performance. Further provided is a display assembly.

A mixture of carbazole and triazine derivatives that can be thermally evaporated from one crucible to fabricate thin films for electroluminescent devices is disclosed.

A novel light-emitting element material is provided. Alternatively, a light-emitting element material capable of simplifying a process for manufacturing a light-emitting element is provided. Alternatively, a light-emitting element material capable of reducing the cost for manufacturing a light-emitting element is provided. Alternatively, one embodiment of the present invention provides a light-emitting element material capable of achieving a light-emitting element having favorable emission efficiency. A light-emitting element material including an organic compound which includes a first skeleton having a carrier-transport property and a second skeleton having a light-emitting property in one molecule and in which the molecular weight is less than or equal to 3000, is provided.

Provided is a heterocyclic compound of Formula 1: ##STR00001## and an organic light emitting device comprising the same.

An organic electroluminescence device and a method of manufacturing an organic electroluminescence device, the device including a first electrode; a second electrode on the first electrode; and an emission layer between the first electrode and the second electrode, wherein the emission layer includes a first host represented by the following Formula 1, and a second host represented by one of the following Formula 2-1 to Formula 2-5: ##STR00001## ##STR00002##