A light emitting device that includes a first electrode, a second electrode oppositely disposed to the first electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes an organometallic compound represented by Formula 1:

##STR00001##

Provided are a light-emitting device and an electronic apparatus including the same. The 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. The interlayer includes an emission layer, and a hole transport region between the first electrode and the emission layer. The emission layer includes a transition metal-containing organometallic compound. The hole transport region includes an electron-blocking layer. The electron-blocking layer includes a first electron-blocking material and a second electron-blocking material, and the first electron-blocking material and the second electron-blocking material have different hole mobilities.

Embodiments provide a cyclic compound, a light-emitting device including the cyclic compound, and an electronic apparatus including the light-emitting device. 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 at least one cyclic compound. The cyclic compound is represented by Formula 1:

##STR00001##

The description of Formula 1 is provided in the specification.

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. The interlayer includes an emission layer and a hole transport layer between the first electrode and the emission layer. The emission layer includes a first host, a second host, and a dopant, wherein the first host includes a hole-transporting host, and the second host includes an electron-transporting host or a bipolar host. The hole transport layer includes multiple hole transport layers, the hole transport layers each include a carbazole-based compound, and highest occupied molecular orbital (HOMO) energy levels of the carbazole-based compounds respectively included in neighboring ones of the hole transport layers are different from each other.

A composition is disclosed that includes a first compound capable of functioning as a host in an emissive layer of an OLED at room temperature; and a second compound that includes a ligand L.sub.A of Formula III ##STR00001##
where ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring; where R represents two adjacent substituents that are joined together to form a ring that is fused to ring B, and R has a structure of Formula IV ##STR00002##
or Formula V ##STR00003##
disclosed herein.

An iridium complex which has a phenylpyridine bidentate ligand containing a group represented by the following general formula (A):

##STR00001##

(In the general formula (A), X represents a cyano group or a halogenated alkyl group. L represents a single bond or a divalent linking group. R represents a substituent. n represents an integer of 0 to 4. * represents a binding site to a phenylpyridine bidentate ligand.)

The present invention relates to a compound having the Formula (I) an intermediate of the compound, a process for preparing the compound, an organic semiconducting material comprising the compound and an organic electronic device comprising the same. The invention further relates to a display device or a lighting device comprising the organic electronic device.

##STR00001##

Embodiments provide an organometallic compound, a light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device. 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 organometallic compound, which is represented by Formula 1.

##STR00001##

The description of Formula 1 is provided in the specification.

The present application relates to a nitrogen-containing compound. The structural formula of the nitrogen-containing compound is as shown in a Formula 1, in which a ring A and a ring B are each independently selected from a benzene ring or a fused aromatic ring with 10 to 14 ring-forming carbon atoms, and at least one of the ring A and the ring B is selected from the fused aromatic ring with 10 to 14 ring-forming carbon atoms; L is selected from a single bond, a substituted or unsubstituted arylene group with 6 to 30 carbon atoms, and a substituted or unsubstituted heteroarylene group with 3 to 30 carbon atoms; and Het is a substituted or unsubstituted nitrogen-containing heteroaryl group with 3 to 30 carbon atoms. The nitrogen-containing compound of the present application can improve the luminous efficiency of an organic electroluminescent device and the conversion efficiency of a photoelectric conversion device using the nitrogen-containing compound. ##STR00001##

In one aspect, provided is a compound of Formula I,

##STR00001##

In Formula I, M is Pt or Pd; L has the structure

##STR00002##

F.sub.1 is

##STR00003##

or a direct bond; rings A, B, C, D, and F are independently monocyclic rings or multicyclic fused ring systems; each of X.sup.1 to X.sup.10 is independently C or N; each of Z.sup.1 to Z.sup.4 is C or N; each of L.sup.1 to L.sup.5 is a direct bond or an organic linker; each of a, b, c, and d is 0 or 1; each K.sup.1 to K.sup.4 is a direct bond, O, or S; each of Z.sup.1 to Z.sup.4 that is connected to O or S is C; and each R.sup.A, R.sup.B, R.sup.C, R.sup.D, R.sup.E, and R.sup.X is independently hydrogen or a substituent.