Single-layer electroluminescent devices and photoinduced hydrogen production from an ionic iridium(III) complex

We report the electronic structure and diverse applications of a highly luminescent ionic transition metal complex, [Ir(dF(CF3)PPY)(2)(dtbbpy)](PF6) (where dF(CF3)ppy = 2-(2,4-difluorophenyl)-5-trifluoromethylpyridine and dtbbpy = 4,4'-di-tert-butyl-2,2'-dipyridyl). The large HOMO-LUMO gap (Delta 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 (Esse = 1.21 V) enabled effective catalysis of the photoinduced reduction of H2O 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).