A brief review of photoactive materials for photoelectrochemical biosensors

Photoelectrochemical (PEC) biosensors have drawn growing interest due to their capability to detect biomolecules with the help of generating photocurrent during oxidation reactions, followed by their high sensitivity, minimal background interference, cost-efficiency, and portability. This review provides an extensive summary of the photoactive materials that power PEC biosensor performance. We start by outlining the basic ideas and signal-generating processes of PEC biosensing, highlighting the crucial role of charge-carrier dynamics in photocurrent production. The article's main body thoroughly examines several categories of photoactive materials, such as metal oxides, quantum dots, organic materials, plasmonic nanostructures, and two-dimensional nanomaterials. We go over the special qualities, charge-transfer methods, light-harvesting capacities, and effects on biosensor performance of each material type, all supported by current experimental research. To improve sensitivity and selectivity, we also examine key design techniques, including heterojunction formation, surface functionalization, and hot-electron injection. We also discuss the main issues in PEC biosensors, including interference reduction, biocompatibility, material stability, and reproducibility. Lastly, we discuss future directions, emphasizing new materials, innovative device designs, and potential applications in food safety, environmental monitoring, and point-of-care diagnostics. The goal of this thorough overview is to assist researchers in choosing and creating cutting-edge photoactive materials for high-performance PEC biosensors of the future.