Dye-sensitized solar cells composed of Ti1−xSnxO2 nanocrystals

Ti1−xSnxO2 nanocrystals were successfully synthesized by using a simple solvothermal route, and its band energy gap broaden and flat band potential can be rationally regulated with increasing x value. Furthermore, Ti1−xSnxO2 nanocrystals were first used as the photoelectrode material for dye-sensitized solar cells. A cell made of Ti1−xSnxO2 (x = 0.3) exhibited the best photovoltaic performance. This is due to its most narrow band gap energies, most negative flat band potential and lowest dark current densities. After the surface of Ti1−xSnxO2 (x = 0.3) electrode was treated with TiCl4 solution, the cell sensitized by a mixed solution of N719 and D131 dye exhibited the best efficiency of 4.64% under the illumination of 1 sun (AM1.5, 100 mW cm−2).

► Ti1−xSnxO2 nanocrystals were used as an electrode for dye-sensitized solar cells.
► The efficiency can be improved obviously after the electrode was treated with TiCl4.
► The best efficiency of 4.64% was obtained using a mixed solution of N719 and D131.