Enhanced efficiency of perovskite solar cells by introducing controlled chloride incorporation into MAPbI 3 perovskite films

Abstract Compositional engineering of mixed halides is an effective approach to fabricate highly efficient perovskite solar cell. The mixed halide perovskite of MAPbI 3-x Cl x attracts a great of attentions due to its excellent optoelectronic properties. However, the role of chlorine in MAPbI 3-x Cl x is still under discussion by now. Here we introduce PbCl 2 as additives into PbI 2 /DMF solution to study its effects on the formation of MAPbI 3-x Cl x film, which is fabricated from Lewis acid-base adducts through a modified two step method. We demonstrate that the chloride ions have positive roles in fabrication of high quality perovskite MAPbI 3-x Cl x films, characterized by high crystallization, strong grain orientation, large grain size and lower trap densities. Compared to perovskite solar cells without chloride incorporation, the performance of solar cells based on MAPbI 3-x Cl x improves significantly due to its high carrier mobility, efficient carrier transportation and low recombination in device.