Interfacial Charge Transfer Engineering in V₃O₅/ZnO p–n Heterostructures for Enhanced SERS Performance

Abstract

Surface-enhanced Raman scattering (SERS) substrates based on transition metal oxides have garnered significant attention due to their structural diversity, tunable properties, and unique optical characteristics. However, their practical applications have been severely hindered by relatively weak Raman enhancement effects and poorly understood charge transfer mechanisms. To address these limitations, this study developed a novel charge-transfer-enhanced SERS substrate by constructing a V3O5/ZnO p-n semiconductor heterojunction. The optimized heterostructure achieved an exceptional methylene blue detection limit of 10-8 M and an enhancement factor of 5.9×104. Through picosecond-resolution transient absorption spectroscopy, the charge transfer dynamics at the heterojunction interface were precisely monitored, providing systematic insights into the microscopic mechanism underlying the Raman enhancement. This study provides a strategy for designing high-performance SERS substrates based on non-precious metals and insights into the charge transfer mechanism revealed by transient absorption spectroscopy.