Recent Progress on Photoelectrochemical Agricultural Detection Sensors: Elucidating the Optoelectronic Signal Amplification Mechanism and the Sensing Mechanism

Photoelectrochemical (PEC) sensors have demonstrated significant potential in agricultural detection due to their high sensitivity, rapid response, and low cost. While significant research efforts have been dedicated to optimizing photoelectrode architectures and designing efficient photoactive materials for agricultural detection, there remains a lack of systematic discussion on the mechanistic interplay between light–energy conversion and target recognition in photoelectrochemical (PEC) sensors. This review comprehensively summarizes recent advances in PEC agricultural sensors, focusing on three core design rationales: (1) enhancing light absorption (doping, nanostructures), (2) optimizing charge transport (surface plasmon resonance effect, quantum dot sensitization, 2D materials/metal–organic frameworks (MOFs)), and (3) developing specific recognition elements. PEC sensors achieve target detection by converting light energy into electrical signals through photoelectrodes and integrating specific recognition elements (e.g., enzymes, antibodies, aptamers, or molecularly imprinted polymers). Furthermore, the article summarizes typical application scenarios of PEC sensors in agricultural detection (e.g., soil component analysis, pesticide residue detection, and antibiotic and mycotoxin monitoring) and provides insights into future developments. These advancements offer crucial theoretical references and technical support for precision monitoring in smart agriculture.