High-performance underwater weak-light photoelectrochemical photodetection based on ZnIn-LDH nanosheet arrays

Abstract

Because the underwater environment strongly absorbs light, photoelectrochemical-type photodetectors (PEC PDs) with good sensitivity to weak light show good potential in underwater optoelectronic devices. In this work, we fabricated novel ZnIn-LDH vertical nanosheet arrays (NSAs) via the potentiostatic electrodeposition technique and demonstrated their good ultraviolet (UV) photodetection. ZnIn-LDH NSA-based PEC UV PDs show high-performance self-powered UV photoresponse, including a high responsivity of 182.41 mA W⁻¹ and a high detectivity of 1.37 × 10¹¹ Jones under low-intensity 254 nm irradiation, outstanding wavelength-selectivity (R_254nm/R_455nm = 7027.03), fast response time (7/10 ms), and good stability, superior to those of most two-dimensional (2D) layered materials and traditional wide-bandgap semiconductors. The unique vertical nanosheet structure is conducive to photogenerated carrier separation, provides more electrochemically active sites, and promotes interfacial charge transfer, leading to higher photoresponse. In addition, the underwater optical communication (UOC) system based on ZnIn-LDH NSA PEC UV PDs is constructed, and the devices show good communication capability under 100 Hz modulated light, demonstrating their potential application in UOC. This work indicates that ZnIn-LDH is a promising candidate for high-performance PEC UV PDs.