Gold Plasmophores for Plasmon-Enhanced Photoelectrochemical Sensing Based on Metal Nanostructures

Surface plasmon-enhanced photoelectrochemical (PE-PEC) processes have garnered growing interest due to their high sensitivity and reduced energy consumption. In this work, a semiconductor-free PE-PEC platform is developed by integrating plasmonic gold nanorods (Au NRs) with gold nanoclusters (Au NCs). The system is constructed by depositing a monolayer of Au NRs with a thin SiO2 spacer layer onto an Au NC-modified gold electrode. Experimental results supported by theoretical simulations demonstrate that near-field enhancement arising from plasmonic coupling between adjacent Au NRs significantly improves charge carrier excitation and photocurrent generation in the Au NCs. The PE-PEC platform was evaluated for the detection of biologically relevant model analytes, namely, hydrogen peroxide and catechol. Compared to electrodes modified with Au NCs alone, the PE-PEC system exhibits markedly enhanced sensitivity for both analytes. These results highlight the potential of rationally designed plasmon-enhanced architectures for improving photoelectrochemical performance and advancing multifunctional PEC-based bioanalysis.