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

Abstract

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.