Optoelectronic devices are widely used in optical logic systems, optical communications, optical imaging and other fields, but traditional optoelectronic devices can only generate unidirectional photocurrent, which hinders the simplification and multi-functionality of devices. In recent years, the controllable reversal of photocurrent direction (bipolar current) in photoelectric systems has become a new research hotspot. Compared with traditional devices, devices with bipolar current increase the reverse current operating state, which is more suitable for the development of new multi-functional optoelectronic devices. Photoelectrochemical (PEC) systems encompass chemical processes such as ion diffusion, migration, and electrochemical reactions that are not present in solid-state transistor devices due to the presence of electrolytes, and the effect of electrolyte pH on PEC system performance is often overlooked. Qiu Meng's team from the School of Chemistry and Chemical Engineering, Ocean University of ChinaA MNPs3-based PEC photodetector was fabricated, and the photocurrent was reversed by adjusting the pH value of the electrolyte, i.e., the electrolyte-controlled photoelectrochemical switching (PEPS) effect. The influence of pH on the direction of photocurrent is clarified from the perspective of electrolyte energy level rearrangement** and semiconductor electrode dynamics theory. This work not only contributes to a deeper understanding of the carrier transport process in the PEC process, but also inspires the development of more advanced multifunctional optoelectronic devices.
Taken from: ACS Appl mater.interfaces 2023, 15, 55938 55947, original link: