Anthocyanin-sensitized nanoporous TiO2 photoelectrochemical solar cells prepared by a sol–gel process

Abstract

Photoelectrochemical solar cells comprising a colloidal TiO2 photoelectrode and sensitized with anthocyanin pigments, delphinidin purple and cyanidin 3,5-diglucose extracted from Hibiscus sabdariffa and Ribes nigra plants, respectively, have been fabricated. A sunlight-to-electricity conversion efficiency of 3.16% under simulated solar light was obtained with the cell sensitized with the delphinidin purple dye. Open-circuit photovoltages of 0.2–0.3 V and short-circuit photocurrents of 15–30 mA/cm2> were obtained, which points to efficient charge-carrier injection at the semiconductor/electrolyte interface. The cells also showed a high activation energy of between 0.3–0.5 eV.