A light-emitting device including a heterocyclic compound represented by Formula 1 and a phosphorescent dopant, and an electronic apparatus including the light-emitting device are provided. Formula 1 is the same as described in the present specification. The 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 the heterocyclic compound represented by Formula 1.

##STR00001##

An organometallic compound and an organic light-emitting device including the same are provided. The organometallic compound is represented by Formula 1:
M(L.sub.A).sub.n1(L.sub.B).sub.n2.  <Formula 1>

Provided are compounds comprising anionic bidentate ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications. Also provided are formulations comprising these compounds comprising anionic bidentate 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 anionic bidentate ligands L.sub.A that are ligands of Pt and Ir complexes for OLED applications.

A light-emitting element includes a light-emitting layer including a guest, an n-type host and a p-type host between a pair of electrodes, where the difference between the energy difference between a triplet excited state and a ground state of the n-type host (or p-type host) and the energy difference between a triplet excited state and a ground state of the guest is 0.15 eV or more. Alternatively, in such a light-emitting element, the LUMO level of the n-type host is higher than the LUMO level of the guest by 0.1 eV or more, or the HOMO level of the p-type host is lower than the HOMO level of the guest by 0.1 eV or more.

Provided is a polycyclic compound of Formula 100:

##STR00001## where Cy3 and Cy4 are the same as or different from each other, and are each independently one selected from the group consisting of a substituted or unsubstituted aromatic hydrocarbon ring, a substituted or unsubstituted aliphatic hydrocarbon ring, and a substituted or unsubstituted aromatic hetero ring, or a ring in which two or more rings selected from the group are fused,
and an organic light-emitting element comprising the same.

An organic light emitting device including a light emitting layer, which comprises one or more of compounds represented by Formulae 1-1 to 1-3; and a compound represented by Formula 2.

##STR00001## ##STR00002##

A polycyclic compound represented by Formula 1:

##STR00001##

wherein, in Formulae 1, ring CY.sub.1, ring CY.sub.2, and ring CY.sub.3 are each independently a C.sub.5-C.sub.30 carbocyclic group or a C.sub.1-C.sub.30 heterocyclic group; X.sub.1 is B, N, P, P(═O), P(═S), Al, Ga, As, C(R.sub.4), Si(R.sub.4), or Ge(R.sub.4); Y.sub.1 and Y.sub.2 are each independently O, S, Se, B(R.sub.5), N(R.sub.5), C(R.sub.5)(R.sub.6), Si(R.sub.5)(R.sub.6), Ge(R.sub.5)(R.sub.6), Ga(R.sub.5), As(R.sub.5) P(R.sub.5), P(═O)(R.sub.5), P(═S)(R.sub.5), or Al(R.sub.5); and R.sub.1, R.sub.2, R.sub.3, b1, b2, and b3 are as provided herein.

A composition comprising a first compound, a second compound, and a third compound, wherein the first compound, the second compound, and the third compound are different from each other, the first compound satisfies one of Condition 1 and Condition 2 as described herein, and the second compound includes a compound represented by Formula 1:

##STR00001##

wherein ring A.sub.1 is a condensed cyclic group in which 3 or more cyclic groups are condensed with each other, and the 3 or more cyclic groups are each a C.sub.5-C.sub.30 carbocyclic group or a C.sub.1-C.sub.30 heterocyclic group; a1 is an integer from 1 to 5; b1 is an integer from 3 to 10; and L.sub.1, R.sub.1, and R.sub.2 are as described herein.

Provided are a condensed cyclic compound represented by Formula 1, an organic light-emitting device including the condensed cyclic compound, and an electronic apparatus including the light-emitting device:

##STR00001## wherein details of Formula 1 are the same as described in the present specification.

A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and a light emitting area disposed between the first electrode and the second electrode and including a phosphorescent dopant, a hole transporting host, and an electron transporting host, wherein the light emitting area includes at least one auxiliary light emitting layer including a thermally activated delayed fluorescence dopant, the hole transporting host, and the electron transporting host and spaced apart from the first electrode and the second electrode.