PDMS‐Assisted Low‐Temperature Synthesis of Submillimeter All‐Inorganic Halide Perovskite Microcrystals for High‐Performance Photodetectors

Abstract All‐inorganic halide perovskites (AIHPs) are promising photovoltaic materials that have been extensively studied in the last decade. In addition, lead‐free AIHPs are preferred because of their non‐toxic and environmentally friendly nature. However, the quality of AIHPs fabricated by conventional solution processing methods is usually unsatisfactory, which leads to poor photoelectric performance. Herein, a facile polydimethylsiloxane‐assisted slow evaporation method that can be readily used to synthesize high‐quality AIHP microcrystals (MCs) (CsPbBr 3 , Cs 2 AgBiBr 6 , and L‐Cs 3 Sb 2 I 9 ) is demonstrated. The photodetection properties of the synthesized AIHP MCs and their spin‐coated thin‐film counterparts are thoroughly studied and compared. Owing to their superior crystallinity, AIHP MCs show better photoelectric performance than spin‐coated films. The responsivity of the CsPbBr 3 microcrystal photodetectors is ≈590 000 mA W −1 . This work proposes a universal solution‐processing method for the successful fabrication of high‐quality all‐inorganic lead‐based (CsPbBr 3 ), lead‐free (L‐Cs 3 Sb 2 I 9 ), and double (Cs 2 AgBiBr 6 ) perovskites, which can overcome the bottleneck in the development of halide perovskites and promote their applications.