High‐Performance Quasi‐2D Sn‐Pb Perovskite Photodetectors for High‐Fidelity Image Sensing and Optical Communication

Abstract Developing stable and efficient photodetectors (PDs) for environmentally friendly applications such as biological imaging, optical communications, and wearable electronics demands novel materials with improved optoelectronic properties. Herein, by precisely controlling the Pb 2 ⁺ content (3%, 6%, and 12%) using a galvanic displacement reaction (GDR), we created a mixed 2D/3D phase structure that enhances the quality of the Sn‐Pb thin films, which improved crystalline orientation, suppressed trap‐assisted recombination and reduced Sn 2+ oxidation processes, resulting in superior environmental stability under air exposure conditions. The flexible device demonstrated robust stability, maintaining performance after 4000 bending cycles or 96 h of storage in ambient conditions. The self‐powered quasi‐2D Sn‐Pb PDs exhibit an impressively low dark current of 1.2 × 10 −8 A cm −2 , rapid rise and decay time of 684 and 683 ns, a peak responsivity of 405 mA W −1 , and a peak detectivity of 1.19 × 10 13 Jones at 710 nm. Additionally, under LED illumination (λ = 910 nm), the photodetectors also demonstrate high fidelity in optical signal transmission, successfully facilitating encrypted communication sequences and image transmission at a rate of 25 kbps. This work presents a promising strategy for developing high‐performance, stable quasi‐2D Sn‐Pb perovskite photodetectors, highlighting their potential for next‐generation photodetectors in flexible, real‐world environments.