A self-powered molecular imprinted photoelectrochemical sensor for streptomycin cathodic detection based on a signal amplification of ZnO/ZnS/Ag2S photoanode

A self-powered molecular imprinted photoelectrochemical (PEC) sensor was first constructed for the sensitive detection of streptomycin (STR) based on ZnO/ZnS/Ag2S photoanode and Fe-doped CuBi2O4 (CBFO) photocathode. A direct electron transfer pathway and enhanced light capture capability was realized by elaborate design of ZnO/ZnS/Ag2S core/shell/shell (CSS) structure. Meanwhile, a well-matched band-edge energy level between ZnO, ZnS and Ag2S not only accelerated the separation of photogenerated carriers, but also amplified photoelectric signal. Molecularly imprinted polymers (MIPs) were prepared at the CBFO photocathode, which could recognize and bind target molecules with selectivity. The inherent deviation between the Fermi level of the photoanode and the photocathode without an external power supply guarantees sufficient photocurrent driving force for the self-powered system. The proposed self-powered PEC sensor improved anti-interference ability and sensitivity, which completed rapid detection for STR, displayed a wider detection range (0.01 nM-10 mM) and lower detection limit (0.0053 nM, S/N = 3), also exhibited good stability and outstanding reliability. This study demonstrates that a rapid, miniaturized self-powered sensing platform has great practical potential for monitoring food safety.