Synergistic enhancement effect of polydopamine–polyethyleneimine hybrid films for a visible-light photoelectrochemical biosensing interface

Photoelectrochemical (PEC) active interfaces exhibiting visible-light responses and good electron-transfer capabilities are key to the development of PEC biosensors. In this study, bioinspired polydopamine (PDA)–polyethyleneimine (PEI) hybrid films were designed to engineer inorganic semiconductors and construct PEC biosensing interfaces. The charge-transfer capability and visible-light-response property of PDA were combined with the electron-attracting ability of PEI to produce a synergistic PEC-enhancement effect. The achieved PEC-enhancement effect was versatile for photoanode and photocathode semiconductors. Further, the role of PEI doping was revealed via electrochemical investigations. Compared with the PDA sensing platform, the hybrid sensing interface offered by the PDA–PEI film exhibited enhanced analytical performances toward ascorbic acid (AA), achieving a larger detection range and a lower limit of detection.