PDMS-Assisted Low-Temperature Synthesis of Submillimeter All-Inorganic Halide Perovskite Microcrystals for High-performance Photodetectors

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) (CsPbBr₃, Cs₂AgBiBr₆, and L-Cs₃Sb₂I₉) 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 CsPbBr₃ 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 (CsPbBr₃), lead-free (L-Cs₃Sb₂I₉), and double (Cs₂AgBiBr₆) perovskites, which can overcome the bottleneck in the development of halide perovskites and promote their applications.