Co-sensitization of TiO2 by PbS quantum dots and dye N719 in dye-sensitized solar cells

Abstract PbS quantum dots (QDs) were prepared by an in-situ chemical bath deposition method, where the QD size is manipulated by adjusting the dipping time in the respective Pb 2+ and S 2− ion solutions. They are characterized by using XPS and UV–visible absorption. The photovoltaic performances of the dye-sensitized solar cells constructed from PbS-sensitized TiO 2 , N719-sensitized TiO 2 and co-sensitized TiO 2 have been evaluated. PbS QDs are shown to elevate the open circuit voltage ( V oc ) and consequently increase the efficiency from 5.95% by N719-sensitized TiO 2 , to 6.35%, by the co-sensitized TiO 2 . The operating mechanism involved in the co-sensitization is presented and discussed.