20‐mm‐Large Single‐Crystalline Formamidinium‐Perovskite Wafer for Mass Production of Integrated Photodetectors

CH 3 NH 3 PbX 3 (MAPbX 3 )‐based perovskite has attracted tremendous research efforts in the last few years. With the discovery that the HC(NH 2 ) 2 PbI 3 (FAPbI 3 ) perovskite offers even higher solar cell efficiency, better thermal stability, and broader optical absorption, it is expected that it will provide more excitement in optoelectronic applications including laser, LED, photodetector, etc. The development in preparing large Single‐Crystalline Formamidinium‐Perovskite FAPbI 3 using the inverse‐temperature reactive crystallization process, and associated wafer‐slicing process is presented. The availability of the large Single‐Crystalline Formamidinium‐Perovskite Wafer makes it possible to fabricate integrated circuits. An array of 153 photodetectors on a piece of thin wafer, demonstrating feasibility of mass production of integrated circuits on the perovskite wafer is designed and prepared. It is found that the wafer‐based photodetector shows much superior performance, with 90 times higher photoresponse and broader optical absorption than its thin‐film perovskite counterpart.