Provided is an electroluminescent device. The electroluminescent device includes an anode, a cathode and an organic layer disposed between the anode and the cathode, where the organic layer includes at least a first compound having a structure of H-L-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. The novel material combination consisting of the first compound and the second compound can enable the electroluminescent device to obtain a lower voltage, higher efficiency and an ultra-long lifetime and can provide better device performance. Further provided are a display assembly and a compound combination.

A heteroleptic compound having a Formula Ir(L.sub.A).sub.m(L.sub.B).sub.3-m, having a structure of Formula I

##STR00001##

is disclosed. In Formula I, m is 1 or 2; moieties A, C, and D are each independently monocyclic rings or polycyclic fused ring structures; each R.sup.1, R.sup.2, R.sup.A, R.sup.B, R.sup.C, R.sup.D, and R.sup.E is independently hydrogen or a substituent; if moiety A is a monocyclic 6-membered ring, then the R.sup.A para to N of ring A is not an aryl group; at least one of R.sup.1 and R.sup.2 is selected from the group consisting of aryl, heteroaryl, cycloalkyl, heterocycloalkyl, and combinations thereof; and adjacent substituents can be joined to form a ring. OLEDs, consumer products, and formulations including the heteroleptic compound are also disclosed.

A compound for an organic optoelectronic device, a composition for an organic optoelectronic device including the same, an organic optoelectronic device, and a display device, the compound being represented by Chemical Formula 1:

##STR00001##

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer between the first electrode and the second electrode and including an emission layer, wherein the interlayer includes an organometallic compound of Formula 1:

##STR00001##

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

The device provided herein is an organic electroluminescent device and includes a substrate; a first electrode on the substrate and with high reflectivity; a translucent or transparent second electrode over the first electrode; and a first, a second and a third organic layer included between the first and the second electrode; where the second organic layer has a thickness >80 nm and is made of a second organic material; the third organic layer is a light-emitting layer including at least one light-emitting material and at least one host material; the first organic layer has a conductivity >1×10.sup.−4 S/m and <1×10.sup.−2 S/m; an energy level difference between HOMO energy level of the second organic material and HOMO energy level of the at least one host material is <0.27 eV; and the first electrode and the second organic layer are in direct contact with the first organic layer.

A light-emitting device includes: a first electrode; a second electrode facing the first electrode; an interlayer between the first electrode and the second electrode and including an emission layer; and at least one organometallic compound of Formula 1:

##STR00001##

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

Provided are organometallic compounds including a ligand L.sub.A of the following Formula I

##STR00001##

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

A compound including a first ligand L.sub.A of Formula I,

##STR00001##

is disclosed. In Formula I, ring B is a 5- or 6-membered ring; X.sup.1, X.sup.2, and X.sup.3 are each CR.sup.A or N; R is a 5- or 6-membered carbocyclic or heterocyclic ring, which can be further fused or substituted; and (1) when ring B is an unfused 6-membered ring, X.sup.1 and X.sup.2 are N, and X.sup.3 is C; and (2) when ring B is a fused 6-membered ring, ring B has the structure of Formula II,

##STR00002##

In this structure, the wavy line indicates the point of connection to ring A; Q.sup.1 to Q.sup.6 are each C or N; and, when proviso (2) applies, (I) at least one of X.sup.1, X.sup.2, and X.sup.3 is N; or (II) R is two or more fused or unfused 5- or 6-membered carbocyclic or heterocyclic rings, or (III) at least ring A or R is substituted with a partially or fully deuterated alkyl or partially or fully deuterated cycloalkyl group.

A composition which is useful for producing a light emitting device having excellent external quantum efficiency contains two or more compounds represented by the formula (C-1) and a phosphorescent compound, in which at least one of the compounds represented by the formula (C-1) is a compound in which R.sup.C is a group represented by the formula (C′-1). ##STR00001##
Ring R.sup.1C and Ring R.sup.2C represent an aromatic hydrocarbon ring or an aromatic hetero ring. R.sup.C represents an oxygen atom, a sulfur atom or a group represented by the formula (C′-1). ##STR00002##
Ring R.sup.3C and Ring R.sup.4C represent an aromatic hydrocarbon ring or an aromatic hetero ring. R.sup.C′ represents a carbon atom, a silicon atom, a germanium atom, a tin atom or a lead atom.

A series of thermally stable and highly luminescent cyclometalated tetradentate ligand-containing gold(III) compounds was designed and synthesized. The cyclometalated tetradentate ligand-containing gold(III) compounds can be used as light-emitting material for fabrication of light-emitting devices. The cyclometalated tetradentate ligand-containing gold(III) compounds can be deposited as a layer or a component of a layer using a solution-processing technique or a vacuum deposition process. The cyclometalated tetradentate ligand-containing gold(III) compounds are robust and can provide electroluminescence with high efficiency and brightness. More importantly, the vacuum-deposited OLEDs demonstrate long operational stabilities with half-lifetime of over 29,700 hours at 100 cd m.sup.−2.