Abstract
Formamidinium lead iodide (FAPbI(3)) is a promising candidate as the solar cell absorption layer with a suitable band gap of 1.45eV and excellent optoelectronic properties. In this work, we report a new vacuum flash evaporation method to deposit phase-pure black -FAPbI(3) films in situ on low-temperature substrates without post-annealing, and the area of deposited films can be up to 36cm(2) (6cmx6cm). Besides, the unique relationship between substrate temperature and phases in films is demonstrated for the further development of the method. With the -FAPbI(3) films as the active layer, perovskite solar cells with power conversion efficiency of 12.55% are fabricated.