Novel Zn–Sn–O nanocactus with excellent transport properties as photoanode material for high performance dye-sensitized solar cells

A novel chemically stable Zn-Sn-O nanocactus structure has been synthesized for the first time using a hydrothermal method. The Zn-Sn-O nanocactus structure comprises a Zn poor-Zn(2)SnO(4) plate and Zn-doped SnO(2) nanothorns growing on the plate, both of which have high electron mobilities. The nanocactus is used as the photoanode of dye-sensitized solar cells (DSSCs). The overall power conversion efficiency (PCE) for the Zn-Sn-O nanocactus film reaches 2.21%, which is twice the previous reported efficiency of pure SnO(2). Electrochemical impedance spectroscopy (EIS) measurements show that the Zn-Sn-O nanocactus film has a good effective diffusion length and high intrinsic electron mobility. After TiCl(4) treatment of the Zn-Sn-O nanocactus film, the current density increases nearly three times and the PCE increases to 6.62%, which compares favourably with the P25 DSSCs (6.97%) and is much higher than that of the SnO(2) (1.04%) or Zn(2)SnO(4) (3.7%)-based DSSCs.