Shape-controlled, water-assisted synthesis of 2D luminescent CsPb₂Br₅ perovskite microcrystals for highly responsive...

Cesium-lead-halide (Cs-Pb-Br) perovskites have been a point of interest for researchers since their discovery for their extraordinary optical and electronic properties. Unlike other members of the Cs-Pb-Br family, CsPb₂Br₅ is less explored. Herein, we synthesized 2D CsPb₂Br₅ in an aqueous medium under ambient conditions. The fabrication was confirmed via several characterization techniques. Optical characterization was performed using UV, PL, and TCSPC analysis. Morphological study was conducted using FE-SEM and TEM analysis, which revealed a new square-pyramidal-like morphology. The structural stability of the material under ambient conditions was studied for an extended period to show its reliability in a practical environment. Moreover, the synthesized microcrystals were utilized to fabricate a highly responsive UV detector with significantly low rise and fall times of 1.2 and 2.6 ms, respectively, and a detectivity of 2.36 × 10⁸ Jones.