Enhance the performance of dye-sensitized solar cells by Co-grafting amphiphilic sensitizer and hexadecylmalonic acid on TiO2 nanocrystals

Dye-sensitized solar cells have been fabricated based on nanocrystalline TiO2 film derivatized with an amphiphilic polypyridyl ruthenium complex, cis-RuLL'(SCN)(2) (L = 4,4'-dicarboxylic acid-2,2'-bipyridine, L' = 4,4'-dinonyl-2,2'-bipyridine), as light-harvester and hexadecylmalonic acid (HDMA) as coadsorbent. The cells generated a short-circuit photocurrent of 15.2 mA cm(-2), an open-circuit photovoltage of 764 mV, and a total power conversion efficiency of 7.8% under simulated full sunlight (air mass 1.5, 100 mW cm(-2)). Co-grafting enhanced the photocurrent, photovoltage, and overall conversion efficiency considerably with respect to cells containing no HDMA. Devices showed a good stability under light soaking at 55 degreesC.