Synergistic Enhancement Effect of Piezoelectricity and Surface Plasmon Resonance: Boosting Photoelectrochemical...

Regulating the generation, migration, and separation of photogenerated carriers is of great importance for improving the capability of photoelectrodes, which also provides advantages for construction of high-performance photoelectrochemical (PEC) biosensors. Herein, we report an excellent photoelectrode with a synergistic enhancement effect of piezoelectricity and surface plasmon resonance. The photoelectrode, named Au_NP/CdS_NR/ITO, was fabricated via in situ growth of hexagonal wurtzite cadmium cesium nanorod (CdS_NR) arrays on indium tin oxide (ITO) using a hydrothermal method followed by the photodeposition of gold nanoparticles (Au_NP). Mechanism study reveals that the synergistic enhancement effect on Au_NP/CdS_NR/ITO greatly enhances the photoelectron conversion efficiency and facilitates the efficient separation of photogenerated carriers, thus manifesting an ultrahigh photocurrent of 1.06 mA. By virtue of target-triggered 3,3',5,5'-tetramethylbenzidine dication etching technology, a split-type PEC immunosensor was constructed using Au_NP/CdS_NR/ITO as a proof of concept for highly sensitive and precise detection of carbohydrate antigen 199 with a low detection limit of 5.6 × 10^-5 U mL^-1. The study offers insight into improving photoelectrode property through the regulation of the transport process of photogenerated carriers and also developing high-performance biosensors for more biomolecules.