High performance broadband photoelectrochemical photodetectors based on Cu-doped Bi 2 O 2 Se nanosheets

and a rapid response (rise and decay times of 60 ms). The device enables broad-spectrum detection from 365 to 700 nm in a self-driven mode (0 V bias), and its performance can be tuned by an external bias (up to 0.6 V) and electrolyte concentration. Remarkably, it retains 85% of its initial photoresponse after one month of storage, demonstrating outstanding stability. This study demonstrates the synergistic enhancement of light absorption, carrier transport, and photocurrent generation through elemental doping, providing a key proof of concept for the structural design and performance modulation of high-performance materials for PEC applications.