Carbon-doped titanum dioxide nanocrystals for highly efficient dye-sensitized solar cells

A series of carbon-doped titanium dioxide (C-TiO 2 ) nanocrystals were hydrothermally synthesized using Ti(SO 4 ) 2 and glucose as titania and carbon resources for 12–48 h. Transmission electron microscopy and X-ray powder diffraction analyses demonstrate that these C-TiO 2 nanocrystals are well crystallized and exhibit better particle dispersity than non-doped TiO 2. Compared with pure TiO 2, all dye-sensitized solar cells (DSSCs) assembled from C-TiO 2 nanocrystals exhibited improved short circuit current and open circuit voltage. A highest energy conversion efficiency (6.9%) was achieved on C-TiO 2 synthesized for 24 h, with a significant improvement of 35.3%. The enhancement was attributed to both the less charge recombination and the negative shifting of the flat band potential as demonstrated by dye-adsorption analysis, photoluminescence and electron lifetime measurements.