A light emitting device having excellent luminance life contains an anode, a cathode, a first organic layer disposed between the anode and the cathode and a second organic layer disposed between the anode and the cathode. The first organic layer contains a compound represented by the formula (C-1), and the second organic layer contains a compound represented by the formula (C-1) and a cross-linked body of a crosslinkable material. ##STR00001##
Ring R.sup.1C and Ring R.sup.2C represent an aromatic hydrocarbon ring or an aromatic hetero ring and 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 and R.sup.C′ represents a carbon atom, a silicon atom, a germanium atom, a tin atom or a lead atom.

The present disclosure relates in parts to compounds capable of emitting delayed fluorescence and uses of these compounds in organic light-emitting diodes.

An organometallic compound represented by Formula 1:

##STR00001## wherein, in Formula 1, groups and variables are the same as described in the specification.

The present specification relates to a nitrogen-containing compound, and a color conversion film, a backlight unit and a display apparatus including the same.

A phosphorescent metal complexes containing a ligand L.sub.A having the formula selected from

##STR00001##

is disclosed.

A compound having the formula:

##STR00001##

Formula I is disclosed. The compound is useful as emitters in OLEDs.

A compound having a structure of ##STR00001##
is disclosed. In these formulas, each R.sub.1, R.sub.2, and R.sub.3 is independently selected from hydrogen, alkyl, and aryl; at least one of R.sub.1 and R.sub.2 is a branched alkyl containing at least 4 carbon atoms, where the branching occurs at a position further than the benzylic position; where R.sub.1 and R.sub.3 are mono-, di-, tri-, tetra-, or no substitutions; and R.sub.2 is mono-, di-, or no substitutions. Heteroleptic iridium complexes including such compounds, and devices including such compounds are also disclosed.

Provided is a light-emitting element with high external quantum efficiency and a low drive voltage. The light-emitting element includes a light-emitting layer which contains a phosphorescent compound and a material exhibiting thermally activated delayed fluorescence between a pair of electrodes, wherein a peak of a fluorescence spectrum and/or a peak of a phosphorescence spectrum of the material exhibiting thermally activated delayed fluorescence overlap(s) with a lowest-energy-side absorption band in an absorption spectrum of the phosphorescent compound, and wherein the phosphorescent compound exhibits phosphorescence in the light-emitting layer by voltage application between the pair of electrodes.

Compounds containing indolocarbazole compounds of Formula I or Formula II comprising terphenyl groups and compounds of Formula III comprising triazine groups are disclosed in this application. These compounds are useful for application in organic electroluminescent devices. ##STR00001##

A novel compound having a first ligand L.sub.A of

##STR00001##

is disclosed. The compound is useful as emitter dopant in OLEDs.