We report the electronic structure and diverse applications of a highly luminescent ionic transition metal complex, [Ir(dF(CF 3 )ppy) 2 (dtbbpy)](PF 6 ) (where dF(CF 3 )ppy ) 2-(2,4-difluorophenyl)-5-trifluoromethylpyridine and dtbbpy ) 4,4′-di-tert-butyl-2,2′-dipyridyl). The large HOMO-LUMO gap (∆E ) 3.06 V) enabled high-energy electroluminescence from the complex. Single-layer devices were fabricated and found to emit blue-green light (500 nm). The strong reducing strength of the excited state (E* ox ) 1.21 V) enabled effective catalysis of the photoinduced reduction of H 2 O to H 2 . It was found that the relative quantum yield of hydrogen was over an order of magnitude improved from the standard photosensitizer Ru(dmphen) 3 2+ (dmphen ) 4,7-dimethyl-1,10-phenanthroline).

We report on the spectroscopic, electrochemical, and electroluminescent properties of [Ir(ppy)(2)(dtb-bpy)](+)(PF(6))(-) (ppy: 2-phenylpyridine, dtb-bpy: 4,4'-di-tert-butyl-2,2'-dipyridyl). Single-layer devices were fabricated and found to emit yellow light with a brightness that exceeds 300 cd/m(2) and a luminous power efficiency that exceeds 10 Lm/W at just 3 V. The PF(6)(-) space charge was found to dominate the device characteristics.