A compound of:

##STR00001##

is disclosed. In Formula III, ring B and ring C are each independently a 5 or 6-membered carbocyclic or heterocyclic ring; A-B represents a bonded pair of carbocyclic or heterocyclic rings coordinated to a metal M via a nitrogen atom in ring A and an sp.sup.2 hybridized atom in ring B; A-C represents a bonded pair of carbocyclic or heterocyclic rings; M is a metal having an atomic number greater than 40; L′ is a monoanionic bidentate ligand; m is the oxidation state of the metal M; and n is at least 1.

A series of novel donor-acceptor type TADF luminogens have been designed with the aim of developing stable OLEDs with enhanced operational stability and improved color purity. These materials could be found utilization for full color displays and lighting applications.

A compound of: ##STR00001##
is disclosed. In Formula IV, ring B and ring C are each independently a 5 or 6-membered carbocyclic or heterocyclic ring; A-B represents a bonded pair of carbocyclic or heterocyclic rings coordinated to a metal M via a nitrogen atom in ring A and an sp.sup.2 hybridized atom in ring B; A-C represents a bonded pair of carbocyclic or heterocyclic rings; M is a metal having an atomic number greater than 40; L′ is a monoanionic bidentate ligand; m is the oxidation state of the metal M; and n is at least 1.

Provided are compounds comprising a first ligand L.sub.A comprising at least two 5-membered or 6-membered carbocyclic rings, wherein at least one of the two 5-membered or 6-membered carbocyclic rings is further substituted with a bicyclic structure containing two nitrogen atoms and one of O, S, CRR′, and SiRR′. Also provided are formulations comprising these compounds. Further provided are organic light emitting devices (OLEDs) and related consumer products that utilize these compounds.

An organic light-emitting device including a first compound represented by Formula 1 and a second compound represented by one of Formulae 2A and 2B. ##STR00001##

The present invention relates to a novel indole-based compound having excellent hole injection and transport capabilities, light-emitting capabilities, and the like, and an organic electroluminescence device which includes the indole-based compound in one or more organic material layers thereof so as to improve characteristics such as light-emitting efficiency, driving voltage, and lifespan.

Embodiments relate to a delayed fluorescence compound and a display device including the delayed fluorescence compound. The delayed fluorescence compound includes an electron acceptor moiety of benzo[4,5]thieno[2,3-b]quinoxaline and at least one electron donor moiety covalently bonded to the electron acceptor moiety. The at least one electron donor moiety is covalently bonded to a benzene ring of benzo[4,5]thieno[2,3-b]quinoxaline and is selected from carbazole, phenylcarbazole, acridine, and phenylacridine. The effective charge transfer in the delayed fluorescence compound results in improved emitting efficiency of the compound.

The present invention relates to metal complexes and to electronic devices, in particular organic electroluminescent devices, comprising these metal complexes.

A dual host system for OLEDs that contains hole-transporting indolocarbazole and electron-transporting indolocarbazole exhibiting superior performance in the OLEDs is disclosed.

The present invention relates to metal complexes and electronic devices, in particular organic electroluminescent devices, containing said metal complexes.