Formamidinium Lead Bromide (FAPbBr3) Perovskite Microcrystals for Sensitive and Fast Photodetectors

Because of the good thermal stability and superior carrier transport characteristics of formamidinium lead trihalide perovskite HC(NH2)(2)PbX3 (FAPbX(3)), it has been considered to be a better optoelectronic material than conventional CH3NH3PbX3 (MAPbX(3)). Herein, we fabricated a FAPbBr(3) microcrystal-based photodetector that exhibited a good responsivity of 4000 A W-1 and external quantum efficiency up to 10(6)% under one-photon excitation, corresponding to the detectivity greater than 10(14) Jones. The responsivity is two orders of magnitude higher than that of previously reported formamidinium perovskite photodetectors. Furthermore, the FAPbBr(3) photodetector's responsivity to two-photon absorption with an 800-nm excitation source can reach 0.07 A W-1, which is four orders of magnitude higher than that of its MAPbBr(3) counterparts. The response time of this photodetector is less than 1 ms. This study provides solid evidence that FAPbBr(3) can be an excellent candidate for highly sensitive and fast photodetectors.