Synthesis and Photovoltaic Properties of Novel Ruthenium(II) Sensitizers for Dye-sensitized Solar Cell Applications

Abstract

Three heteroleptic ruthenium sensitizers, Ru(L)(L(1))(NCS)(2) [L=4,4'-dicarboxylic acid-2,2'-bipyridine, RuAl : L(1) = (E)-2-(4'-methyl-2.2'-bipyridin-4-yl)-3-(thiophen-2-yl)acrylonitrile, Ru-T2 L(2)=(E)-3-(5'-hexyl-2,2'-bithiophene-5-yl)-2-(4'-methyl-2,2'-bipyridin-4-yl)acrylonitrile, and Ru-T3. L(3) = (E)-3)-(5 ''-hexyl-2,2' 5',2 ''-terthiophen-5-yl)-2-(4'-methyl-2,2'-bipyridin-4-yl)acrylonitrile)], were synthesized and used as photosensitizers in nanocrystalline dye-sensitized solar cells (DSSCs). The introduction of the 3-(5-hexyloligothiophen-5-yl)acrylonitrile group increased the conjugation length of the bipyridine donor ligand and thus improved their molar absorption coefficient and light harvesting efficiency. DSSCs with the configuration of SnO(2). F/TiO(2)/ruthenium dye/liquid electrolyte/Pt devices were fabricated using these Ru-T1 similar to T3 as a photosensitizers Among the devices, the DSSCs composed of Ru-T2 exhibited highest power conversion efficiency (PCE) of 2 84% under AM 1 5 G illumination (100 m W/cm(2)).