One Stone, Three Birds: SnO₂ Nanosheet Arrays toward Self-Powered Visible-Blind UV Photodetection with High Responsivity and Rejection Ratio

Photoelectrochemical-type ultraviolet photodetectors (PEC UV PDs) with simple fabrication processes and high sensitivity have attracted ever-growing attention. However, the self-powered performance of PEC UV PDs is still unsatisfying. Herein, the SnO2 nanosheet array (NSA) photoanodes are fabricated and their good self-powered UV detection capability is demonstrated. The 3D structure of SnO2 NSA not only improves the interfacial charge transfer and carrier transport but also enhances UV absorption. Therefore, the self-powered SnO2 NSA-based PEC UV PDs exhibit excellent performance with an ultrahigh responsivity of 207.12 mA W-1, an excellent UV-visible rejection ratio (R-254/R-455 of 3395), a fast response time (25 ms), and good stability under 254 nm illumination, demonstrating one of the recorded-high-performance in the recently reported PEC UV PDs. This work provides more options for developing high-performance PEC UV PDs.