Synthesis of Zn-doped TiO2 nano-particles using metal Ti and Zn as raw materials and application in quantum dot sensitized solar cells

Abstract

Zn-doping in TiO2 gives an n-type doped material and can tailor the optical band gap and Fermi level of TiO2. In the present work, using metal Ti and Zn as raw materials, Zn-doped TiO2 nano-particles are synthesized via chemical co-precipitation and calcination process. The effects of Zn-doping on the morphology, crystal structure, optical behavior of TiO2 films, and the performance of CdS/CdSe sensitized cells are systemically investigated, we focus on improving the power conversion efficiency of the cells based on Zn-doped TiO2 photoanodes. The results show that the solar cell assembled with the Zn0.1Ti0.9O2 film exhibits a short circuit current density of 12.32 mAcm−2, open-circuit voltage of 0.604 V, and a power conversion efficiency of 3.03%. Its power conversion efficiency is 1.5-fold higher than that of the cell assembled with the pure TiO2 film, which is ascribed to reducing electron recombination and enhancing electron transport in the TiO2 film by the optimal Zn doping. Further increasing the amount of Zn doping in the TiO2 film, the performance of the cell decreases, which is attributed to introducing a large number of ZnO clusters and producing more surface defects in the TiO2 film that act as electron–hole recombination centers.