Two-dimensional CuSe nanosheet array for high-performance photoelectrochemical photodetector using simulated seawater as electrolyte

Abstract

Photoelectrochemical-type (PEC) photodetectors (PDs) show great promise in underwater optoelectronic devices, but most reports of PEC PDs use acid or basic solutions as electrolytes, hindering their practical application in marine scenarios. In this letter, we reported high-performance 2D CuSe-based PEC PDs with use of the electrolyte of simulated seawater for the first time. The 2D CuSe nanosheet array (NSA) is synthesized by a facile electrodeposition method. The PEC PDs based on 2D CuSe NAS has a superior responsivity of 9.5 mA/W for 455 nm light in the simulated seawater, and exhibits a broadband photoresponse in 365–850 nm, surpassing most TMCs-based PEC PDs. The superior photoresponse originates from the vertical NSA structure, providing more interfacial active sites and higher light absorption. In addition, 2D CuSe NSA-based PEC PDs possess self-powered ability, fast response speed, good stability, and underwater optical communication capability. This work demonstrates the great potential of 2D CuSe NSA in PEC-type optoelectronic devices.