Mesoscopic nitrogen-doped TiO2 spheres for quantum dot-sensitized solar cells

The photovoltaic performance of quantum dot-sensitized solar cell (QDSSC) based on mesoscopic nitrogen-doped TiO2 spheres prepared by solvothermal method was investigated. The results indicate that CdSexS(1−x)/CdSe QDSSC based on this mesoscopic nitrogen-doped TiO2 spheres shows an energy conversion efficiency of 3.67%, which is higher than that of the undoped TiO2 spheres (2.14%). The electrochemical impedance spectroscopy shows retards charge recombination is occurred on nitrogen-doped TiO2 spheres photoanode. The improvement of the photovoltaic performance of QDSSC could be attributed to the retarding charge recombination, the acceleration of the transfer rate of electrons, higher quantum dots loading and enhanced light scattering in the N-doped TiO2 spheres film. A higher photovoltaic performance could be expected for other QDSSC with this N-doped TiO2 sphere material.

► The mesoscopic N-doped TiO2 spheres show higher energy conversion efficiency. ► EIS shows retards charge recombination occurred on N-doped TiO2 spheres photoanode. ► The acceleration of electron transfer rate was verified by IMPS.