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 °C.