A compound having the formula Ir(L.sub.A).sub.n(L.sub.B).sub.3-n is disclosed wherein L.sub.A is an aza-DBF ligand and L.sub.B is an alkyl-substituted phenylpyridine ligand, wherein the compound has a structure according to Formula I:

##STR00001##

wherein each of A.sup.1 to A.sup.8 comprise carbon or nitrogen; wherein at least one of A.sup.1 to A.sup.8 is nitrogen; wherein ring B is bonded to ring A through a C—C bond; wherein the iridium is bonded to ring A through a Ir—C bond; wherein X is O, S, or Se; wherein R′ and R″ each independently represent mono-, di-substitution, or no substitution; wherein any adjacent substitutions in R′, R″, R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are optionally linked together to form a ring; wherein R.sup.1, R.sup.2, R′, and R″ are each independently selected from a variety of substituents; wherein R.sup.3, R.sup.4, R.sup.5, and R.sup.6 are each independently selected from the group consisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinations thereof; wherein n is an integer from 1 to 3; and wherein total number of carbons in at least one of the pairs R.sup.3 and R.sup.4, and R.sup.5 and R.sup.6 is at least four.

Thermally assisted delayed fluorescent materials with triad-type materials for use in full color displays and lighting applications with the following generic structures are provided: ##STR00001##

A compound having a structure selected from the group consisting of: ##STR00001##
is disclosed.

The present invention provides an organic thin film light-emitting element having improved light-emitting efficiency and durable service life. The compound of the present invention has the structure represented by general formula (1) below. In general formula (1), Ar.sup.1 is an aromatic group having a specific structure, and Ar.sup.2 is a separate aromatic group having a specific structure. n is an integer of 1 or 2, and p is an integer of 1 or 2. However, n+p=3. When n is 2, each Ar.sup.1 may be the same or different, and when p is 2, each Ar.sup.2 may be the same or different. However, Ar.sup.1 and Ar.sup.2 are not the same group. ##STR00001##

There is provided an organic electroluminescence device, including at least an anode, a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode in the stated order, the organic electroluminescence device being characterized in that the hole transport layer contains an arylamine compound represented by formula (1), and the light-emitting layer contains a heterocyclic compound having a fused ring structure represented by formula (2) or a heterocyclic compound having a fused ring stricture represented by formula (3), wherein each of formulas (1), (2) and (3) are set forth in the specification.

An organic optoelectronic device and a display device, the organic optoelectronic device including an anode and a cathode facing each other, a light emitting layer between the anode and the cathode, a hole transport layer between the anode and the light emitting layer, and a hole transport auxiliary layer between the light emitting layer and the hole transport layer, wherein the light emitting layer includes a first compound represented by a combination of Chemical Formula 1 and Chemical Formula 2, and a second compound represented by Chemical Formula 3, and the hole transport auxiliary layer includes a third compound represented by Chemical Formula 4: ##STR00001##

An organic electroluminescence device of an embodiment includes a first electrode, a second electrode, and an emission layer between the first electrode and the second electrode, wherein the emission layer includes a polycyclic compound represented by Formula 1 and shows high emission efficiency and excellent color reproducibility. ##STR00001##

An organic electroluminescence device includes: an anode; an emitting layer; and a cathode, the emitting layer containing a first material, a second material and a third material, the first material being a fluorescent material, the second material being a delayed fluorescent material, the third material having a singlet energy larger than a singlet energy of the second material.

A composition of materials including a first compound having a structure according to Formula I

##STR00001##

Novel host compounds consisting of carbazole and nitrile groups are disclosed. These compounds are useful in phosphorescent OLEDs.