Patent ID: 7473477

Claim:
An OLED device comprising a cathode, an anode, and located therebetween a light emitting layer containing a compound represented by formula (I): A m -M-B n (I) wherein m+n=2 or 3 and neither m nor n is 0; M is Ir, Pt, Os, Ru, Rh, Re or Pd; A m includes at least one ligand A having a triplet energy of at least 2.9 eV as measured in a homoleptic complex of M and A; and B is represented by the formula (II): wherein Q represents an atomic group forming a nitrogen-containing heterocyclic ring; and R5, R6, R7, R8 and R5′ independently represent a hydrogen atom or a substituent; and wherein at least one ligand A of formula (I) is a 1-phenylpyrazole group represented by formula (II): wherein R 1 , R 2 , R 3 , R 4 , R 1 ′, R 2 ′, and R 3 ′ are each hydrogen or an independently selected substituent.