Perovskite-Inspired Lead-Free Ag2BiI5 for Self-Powered NIR-Blind Visible Light Photodetection

Highlights The photodetection capabilities of emerging perovskite-inspired lead-free Ag 2 BiI 5 are investigated. In self-powered mode, a near-constant photoresponse through the visible with a NIR rejection ratio of > 250 is obtained. Optoelectronic characterization provides insight into the interplay among efficiency, collection distance, and film micro-/nano-structure. In recent years, solution-processible semiconductors with perovskite or perovskite-inspired structures have been extensively investigated for optoelectronic applications. In particular, silver–bismuth–halides have been identified as especially promising because of their bulk properties and lack of heavily toxic elements. This study investigates the potential of Ag 2 BiI 5 for near-infrared (NIR)-blind visible light photodetection, which is critical to emerging applications (e.g., wearable optoelectronics and the Internet of Things). Self-powered photodetectors were realized and provided a near-constant ≈ 100 mA W −1 responsivity through the visible, a NIR rejection ratio of > 250, a long-wavelength responsivity onset matching standard colorimetric functions, and a linear photoresponse of > 5 orders of magnitude. The optoelectronic characterization of Ag 2 BiI 5 photodetectors additionally revealed consistency with one-center models and the role of the carrier collection distance in self-powered mode. This study provides a positive outlook of Ag 2 BiI 5 toward emerging applications on low-cost and low-power NIR-blind visible light photodetector.