Flexible Lead Bromide Perovskite Solar Cells

Lead bromide perovskite solar cells (PSCs) have attracted increasing interest partly because of the high open-circuit voltage that has been obtained. Here, we present a simple way to prepare PSCs based on formamidinium lead tribromide, FAPbBr(3), by adding methylammonium chloride and methylammonium bromide into the precursor solution. With this method, high-quality and pin-hole free perovskite films with large crystal sizes were prepared. These additives result in a power conversion efficiency (PCE) of 7.9%, almost free of hysteresis, for a device on a rigid glass substrate. The first flexible lead bromide PSC is also prepared in this work and the flexible PSC exhibited a high PCE of 5.0%.