Two-Dimensional Antimony-Based Perovskite-Inspired Materials for High-Performance Self-Powered Photodetectors

The ongoing Internet of Things revolution has led to strong demand for low-cost, ubiquitous light sensing based on easy-to-fabricate, self-powered photodetectors. While solution-processable lead-halide perovskites have raised significant hopes in this regard, toxicity concerns have prompted the search for safer, lead-free perovskite-inspired materials (PIMs) with similar optoelectronic potential. Antimony- and bismuth-based PIMs are found particularly promising; however, their self-powered photodetector performance to date has lagged behind the lead-based counterparts. Aiming to realize the full potential of antimony-based PIMs, this study examines, for the first time, the impact of their structural dimensionality on their self-powered photodetection capabilities, with a focus on 2D Cs₃Sb₂I_9−xCl_x and Rb₃Sb₂I₉ and 0D Cs₃Sb₂I₉. The 2D absorbers deliver cutting-edge self-powered photodetector performance, with a more-than-tenfold increase in external quantum efficiency (up to 55%), speed of response (>5 kHz), and linear dynamic range (>four orders of magnitude) compared to prior self-powered A₃M₂X₉ implementations (A⁺: monovalent cation; M³⁺: Sb³⁺/Bi³⁺; X⁻: halide anion). Detailed characterization reveals that such a performance boost originates from the superior carrier lifetimes and reduced exciton self-trapping enabled by the 2D structure. By delivering cutting-edge performance and mechanistic insight, this study represents an important step in lead-free perovskite-inspired optoelectronics toward self-powered, ubiquitous light sensing.