Provided is an organic light emitting device comprising a light emitting layer comprising a compound of Chemical Formula 1 and a compound of Chemical Formula 2:

##STR00001## wherein: Ar.sub.1, Ar.sub.2, Ar.sub.4 and Ar.sub.5 are each independently a substituted or unsubstituted C.sub.6-60 aryl or C.sub.2-60 heteroaryl containing N, O or S; Ar.sub.3 is hydrogen, or a substituted or unsubstituted C.sub.6-60 aryl or C.sub.2-60 heteroaryl containing N, O or S; L.sub.1 to L.sub.3 are each independently a single bond or a substituted or unsubstituted C.sub.6-60 arylene; L.sub.4 to L.sub.6 are each independently a single bond or a substituted or unsubstituted C.sub.6-60 arylene or C.sub.2-60 heteroarylene containing N, O or S; L.sub.7 is a substituted or unsubstituted C.sub.6-60 arylene; R.sub.1 is hydrogen, deuterium, or a substituted or unsubstituted C.sub.6-60 aryl or C.sub.2-60 heteroaryl containing one or of N, O and S; a is 0 to 7.

Provided are organometallic compounds that includes a ligand L.sub.A of

##STR00001##

Also provided are formulations comprising these organometallic compounds. Further provided are OLEDs and related consumer products that utilize these organometallic compounds.

An organic electroluminescence device includes: a first electrode; a hole transport region disposed on the first electrode; an emission layer disposed on the hole transport region; an electron transport region disposed on the emission layer; and a second electrode disposed on the electron transport region, wherein the emission layer includes an organometallic compound of Formula 1:

##STR00001##

wherein, in Formula 1, the variables are described herein.

An organic light emitting device (OLED) architecture in which efficient operation is achieved for the OLED having three hosts in the emissive layer by incorporating at least one multi-component functional layer selected from the group consisting of a hole injecting layer, a hole transporting layer, an electron blocking layer, a hole blocking layer, an electron transporting layer, and an electron injecting layer.

Provided is an organic light-emitting device including a first electrode; a second electrode; and an organic layer between the first electrode and the second electrode and comprising an emission layer, wherein the organic layer includes at least one condensed cyclic compound represented by Formula 1.

Provided are compounds of formula Ir(L.sub.A).sub.x(L.sub.B).sub.y(L.sub.C).sub.z wherein the L.sub.A ligand has the Formula I

##STR00001## that are useful as phosphorescent emitters in OLEDs. Also provided are formulations comprising these compounds. Further provided are OLEDs and related consumer products that utilize these compounds.

A organic light-emitting element including a positive electrode, a light-emitting layer, and a negative electrode in this order, wherein the light-emitting layer contains a dopant material, a host material, and an assist material, the dopant material is a compound represented by the following general formula [1], the host material is a hydrocarbon compound, and the assist material has a lower LUMO level than the host material. In the formula [1], R.sub.1 to R.sub.10 denote a hydrogen atom, an alkyl group, or the like. X denotes O or S. m denotes an integer in the range of 1 to 3, and n denotes an integer in the range of 0 to 2, provided that m+n is 3. The partial structure IrL.sub.n is any one of structures represented by the following formulae [2] and [3], wherein R.sub.11 to R.sub.21 denote a hydrogen atom, an alkyl group, or the like.

##STR00001##

Provided are compounds comprising ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications. Also provided are formulations comprising these compounds comprising ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications. Further provided are OLEDs and related consumer products that utilize these compounds comprising ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications.

An organic electroluminescence device includes a first electrode, a second electrode facing the first electrode, and a plurality of organic layers disposed between the first electrode and the second electrode. At least one organic layer includes a fused polycyclic compound represented by Formula 1, thereby exhibiting improved luminous efficiency.

Provided are a light-emitting device and an electronic apparatus. The light-emitting device includes a first electrode, a second electrode facing the first electrode, and an interlayer disposed between the first electrode and the second electrode. The interlayer includes an emission layer and an electron blocking layer, the electron blocking layer includes a first electron blocking layer and a second electron blocking layer. The first electron blocking layer includes a first compound, the second electron blocking layer comprises a second compound, and the first compound is different from the second compound.