Electrophosphorescent Light Emitting Devices Using Mixed Ligand Ir(III) Complexes

We have fabricated phosphorescent light emitting devices using mixed ligand bisorthometalated Ir(III) complexes, chlorobis-(2-phenylpyridinato- N,C 2 ')pyridineiridium(III) [Ir(Cl)(ppy) 2 (py)] and chlorobis-(2-phenylpyridinato- N,C 2' )triphenylphosphine iridium(III) [Ir(Cl)(ppy) 2 P(Ph) 3 ] chlorobis-(2-phenylpyridinato- N,C 2' )tri- n -butylphosphine iridium(III) [Ir(Cl)(ppy) 2 P( n -Bu) 3 ], where ppy is the orthometalating ligand. These complexes vary in their HOMO (highest occupied molecular orbital), LUMO (lowest unoccupied molecular orbital) and emissive states in accordance with the φ-accepting abilities of the non-orthometalating ligands. The lifetimes and EL spectrum of the devices were studied and compared.