Space‐Confined Growth of CsPbBr3 Film Achieving Photodetectors with High Performance in All Figures of Merit

Abstract All‐inorganic halide perovskite is considered as outstanding candidate of organic–inorganic hybrid perovskite due to its superior stability. However, the low solubility of precursor and uncontrollable film growth result in poor film quality and impede the application of polycrystalline films greatly. In this work it is reported on a space‐confined growth strategy to overcome the low solubility and fast crystal growth disadvantages via freezing the precursor solution within the gaps of ordered polystyrene sphere templates. Then, the dense CsPbBr 3 polycrystalline films realize low trap density (3.07 × 10 12 cm −3 ) and high carrier mobility (9.27 cm 2 V −1 s −1 ) after stoichiometric modulation. Photodetectors based on these films exhibit high performance in all figures of merit. Specifically, high responsivity up to 216 A W −1 and ultrashort response time (<5 µs) are achieved, which are better than those of all the CsPbBr 3 based PDs. A record detectivity of 7.55 × 10 13 and 3.1 × 10 5 Hz −3 dB bandwidth are also achieved. This work opens the window of high quality all‐inorganic halide perovskite polycrystalline films and can be extended to rational application of more optoelectronic devices including solar cells, photoelectrodes, and ray detectors.