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

##STR00001##

is provided. In Formula I, each of moiety A and moiety B independently represents monocyclic or polycyclic rings; one of Z.sup.1 and Z.sup.2 is C and the other is N; K is a direct bond, O, or S; at least one R.sup.A or R.sup.B has a structure of Formula II,

##STR00002##

where at least two of X.sup.1 to X.sup.4 are C; L is a direct bond or an organic linker; each R, R′, R″, R.sup.A, R.sup.B, and R.sup.C is a hydrogen or a General Substituent; and L.sub.A is coordinated to a metal M. Formulations, OLEDs, and consumer products containing the compound are also provided.

A light-emitting device with high emission efficiency is provided. The light-emitting device includes at least a light-emitting layer between an anode and a cathode. The light-emitting layer contains a light-emitting substance, a first organic compound, and a second organic compound. The light-emitting substance is a substance that emits fluorescent light. The first organic compound has any one of an anthracene skeleton, a tetracene skeleton, a phenanthrene skeleton, a pyrene skeleton, a chrysene skeleton, a carbazole skeleton, a benzocarbazole skeleton, a dibenzocarbazole skeleton, a dibenzofuran skeleton, a benzonaphthofuran skeleton, a bisnaphthofuran skeleton, a dibenzothiophene skeleton, a benzonaphthothiophene skeleton, a bisnaphthothiophene skeleton, and a fluoranthene skeleton. The second organic compound has any one of a fluorenylamine skeleton, a spirobifluorenylamine skeleton, a dibenzofuranylamine skeleton, a carbazolamine skeleton, a benzocarbazolamine skeleton, a dibenzocarbazolamine skeleton, a dibenzofuranamine skeleton, a benzonaphthofuranamine skeleton, a bisnaphthofuranamine skeleton, a dibenzothiophenamine skeleton, a benzonaphthothiopheneamine skeleton, a bisnaphthothiopheneamine skeleton, and an arylamine skeleton.

A light emitting device of an embodiment 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 represented by Formula 1, thereby showing long life and high efficiency.

A compound comprising a metal M and a first ligand L.sub.A having a structure of Formula I,

##STR00001##

is described. In Formula I, each independently represents a single bond or a double bond; each of X.sup.1′ to X.sup.4′ is independently C, N, or NR′; at least one of X.sup.1 to X.sup.4 is NR′; each R.sup.A′, R′, R.sup.1, R.sup.2, and R.sup.3 is independently hydrogen or a general substituent; at least one of R.sup.A′, R′, R.sup.1, R.sup.2, and R.sup.3 comprises the metal M; when X.sup.1 and X.sup.2 are both NR′, the B atom of Formula I forms a maximum of one direct bond to a nitrogen atom, and does not form a direct bond to an oxygen atom; and any two adjacent R.sup.A, R′, R.sup.1, R.sup.2, and R.sup.3 can be joined or fused to form a ring. Formulations, OLEDs, and consumer products including the compounds are also described.

An organic electroluminescence device of an embodiment includes a first electrode, a second electrode facing the first electrode, and multiple organic layers disposed between the first electrode and the second electrode, wherein the organic layers include at least one organic layer including a fused polycyclic compound represented by Formula 1, thereby showing improved emission efficiency.

##STR00001##

Heteroleptic compounds having a structure of Ir(L.sub.A).sub.p(L.sub.B).sub.q(L.sub.C).sub.r, where L.sub.B and L.sub.C are different bidentate ligands, p is 1 or 2, q is 1 or 2, r is 0, 1, or 2, and ligand L.sub.A has a structure of Formula I,

##STR00001##

In Formula I, moiety B is a monocyclic or polycyclic fused ring system; each of X.sup.1 to X.sup.6 is C or N; each R.sup.A, R.sup.B, and R.sup.C is independently a hydrogen or a general substituent; at least one R.sup.B comprises a partially or fully deuterated alkyl or cycloalkyl group; if moiety B is phenyl, at least two adjacent R.sup.C substituents are fused to form a ring, with the proviso that at least one L.sup.B or L.sup.C is present and is not a phenylpyridine-based ligand. Formulations, OLEDs, and consumer products containing the same are also disclosed.

A light emitting device includes an emission layer disposed between electrodes. The emission layer includes a host and a delayed fluorescence dopant. The delayed fluorescence dopant includes a fused polycyclic compound represented by Formula 1:

##STR00001##

An organometallic compound, represented by Formula 1:

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

wherein M.sub.1 is a transition metal, Ln.sub.1 is a ligand represented by Formula 1-1, Ln.sub.2 is a ligand represented by Formula 2-1 or Formula 2-2, n1 is 1 or 2, and n2 is 1 or 2:

##STR00001##

wherein CY.sub.11, CY.sub.12, X.sub.31, X.sub.32, R.sub.10A, R.sub.10B, R.sub.21 to R.sub.28, R.sub.31 to R.sub.37, R.sub.41 to R.sub.44, b11, and b12 are as defined herein, and * and *′ each indicate a binding site to M.sub.1.

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, 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 X.sub.1, X.sub.2, Y.sub.1, Y.sub.2, Y.sub.3, Y.sub.4, Y.sub.5, Y.sub.6, Y.sub.7, Y.sub.8, Y.sub.9, Y.sub.10, CY.sub.1, CY.sub.2, CY.sub.3, T.sub.1, T.sub.2, a1, a2, R.sub.10, R.sub.20, R.sub.30, b10, b20, and b30 are each as described herein.

An organic EL device includes: an anode; a cathode; an anode side emitting unit; a cathode side emitting unit; a charge generating unit; a first organic layer having a thickness of 40 nm or less; and a second organic layer, in which the anode side emitting unit includes a first emitting layer which is provided close to the anode, a difference between an ionization potential Ip(H1) of a first host material in the first emitting layer and an ionization potential Ip(EBL) of a first organic material in the first organic layer satisfies a relationship of a numerical formula (Numerical Formula A1) below,

Ip(H1)−Ip(EBL)≤0.4 eV  (Numerical Formula A1).