Obtaining white perovskite film for efficient solar cells

White methylammonium lead triiodide perovskite CH3NH3PbI3 (MAPbI3) film was achieved by controlling the process of anti-solvent washing during the spin-coating of MAPbI3 precursor solution, by using a one-step solution deposition method. White perovskite film showed a multi-layer grain packing morphology, which had fewer horizontal grain boundaries. It demonstrated better properties such as larger charge carrier mobility and better contact with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM), which led to a larger short-circuit current (J SC) of a perovskite solar cell of 21.66 mA cm−2, whereas it was 18.7 mA cm−2 for the device based on a common dark-brown perovskite film. The stability of the intermediate phase plays an important role in the morphology of perovskite film.