Preparation of Perovskite Films under Liquid Nitrogen Atmosphere for High Efficiency Perovskite Solar Cells

High-quality perovskite film with high coverage and tight grain arrangement is a key factor for obtaining high performance and stable perovskite devices. Herein, high-quality perovskite films were successfully prepared by a liquid nitrogen assisted method (LN method). Here, the vaporization of liquid nitrogen reduces the ambient temperature and absorbs thermal energy from the substrate surface to increase the nucleation speed of perovskite. The scanning electron microscopy results showed that CH3NH3PbI3 perovskite films prepared by the liquid nitrogen assisted method were dense and pinhole-free. The devices prepared by the LN method result in a high performance with the power conversion efficiency (PCE) up to 16.53%, and the performance could maintain more than 89% of the primary PCE after 30 days storage in a desiccator at room temperature.