High‐crystallinity and large‐grain CH 3 NH 3 PbI 3 thin films for efficient TiO 2 nanorod array perovskite solar cells

Abstract

The high-crystallinity, large-grain and full-coverage CH3NH3PbI3 thin films are successfully prepared by converting the PbI2·dimethyl sulphoxide (DMSO) complex thin films at the optimum annealing temperature and time of 140°C and 10 min in the glove box with the relative humidity of 10–15%. The influence of the annealing temperature and time on the crystallinity, surface morphology, optical absorption of CH3NH3PbI3 thin films is systematically investigated and the photovoltaic performance of the corresponding TiO2 nanorod array perovskite solar cells is evaluated. The results reveal that the crystallinity of CH3NH3PbI3 thin films can be improved and their grain sizes gradually increase from 200–300 to 300–500 and 500–800 nm with the increase of the annealing temperature from 100 to 120 and 140°C. The TiO2 nanorod array perovskite solar cells with the optimum annealing temperature and time of 140°C and 10 min exhibit the best photoelectric conversion efficiency (PCE) of 16.11% and the average PCE of 15.62 ± 0.49%.