Nitrogen doped TiO2–CuxO core–shell mesoporous spherical hybrids for high-performance dye-sensitized solar cells

We report on high-performance dye-sensitized solar cells (DSSCs) based on nitrogen doped anatase TiO2–CuxO core–shell mesoporous hybrids synthesized through a facile and controlled combined sol–gel and hydrothermal process in the presence of hexadecylamine as the structure-directing agent. The matching of band edges between CuxO and TiO2 to form a semiconductor heterojunction plays an important role in effective separation of light induced electrons and holes, providing a promising photoanode for DSSCs because of its wide absorption spectrum, high electron injection efficiency, and fast electron transference. DSSCs based on the mesoporous TiO2–CuxO core–shell hybrids show a high short-circuit current density of 9.60 mA cm−2 and a conversion efficiency of 3.86% under one sun illumination. While DSSCs based on the N-doped mesoporous TiO2–CuxO hybrids exhibit the higher short-circuit current density of 13.24 mA cm−2 and a conversion efficiency of 4.57% under one sun illumination. In comparison with un-doped TiO2–CuxO hybrids, the doping of nitrogen into the lattice of TiO2 can extend the light absorption in the ultraviolet range to the visible light region and effectively decrease the recombination rate of photo-generated electrons and holes. The presented N-doped mesoporous TiO2–CuxO hybrids as photoanodes could find potential applications for high performance DSSCs.