Universal Display Corporation
HOST MATERIALS FOR ELECTROLUMINESCENT DEVICES

Abstract:

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.