Cs2AgBiBr6-based heterojunction photodetector for weak-light imaging application

Abstract

Lead-free all-inorganic Cs2AgBiBr6 perovskite is a promising substitute for the traditional lead-based hybrid perovskites in the field of photoelectric detection devices. Its nontoxic and stable features are particularly important for potential applications used in daily life, such as cameras, monitors, and wearable equipment. In this paper, we report a SnO2/Cs2AgBiBr6 heterojunction photodetector (PD) with an enhanced photodetection performance by post-treatment of isopropanol (IPA) solvent. Benefitting from the construction of heterojunctions and the solvent-based post-treatment of the perovskite surface, the SnO2/Cs2AgBiBr6 PD exhibits excellent self-powered photodetection performance with a responsivity of 48 mA/W, on/off ratio up to 8666, response speed of 248 μs/341 μs, linear dynamic range (LDR) of 108 dB, and specific detectivity of 2.1 × 1012 Jones. Moreover, we built a transmission imaging system using the Cs2AgBiBr6 PD as an imaging sensor. The result demonstrates thunder our Cs2AgBiBr6 PD-based imaging system exhibits high-resolution and high-contrast imaging capability, especially under the weak light condition.