Orchestrated oxygen-vacancy/plasmon synergy in a self-regenerating SERS metasurface for molecular fingerprinting

Monolithic Ag@SrTiO 3 heterostructure enables synergistic plasmon-vacancy coupling. • Conformal Ag nanoparticle coverage maximizes hotspot density and surface utilization. • Oxygen vacancies promote interfacial charge transfer for enhanced SERS activity. • Ultrasensitive detection of Rhodamine 6G with an EF of 2.46 × 10 8 and 10 −10 M limit. • Photocatalytic self-regeneration enables reusable SERS sensing in water matrices. Orchestrating oxygen-vacancy/plasmon synergy within a monolithic Ag@SrTiO 3 heterostructure yields a self-regenerating SERS metasurface for high-fidelity molecular fingerprinting. Through an in situ reduction strategy, Ag nanoparticles are intimately and conformally anchored across the entire SrTiO 3 nanocube surface, achieving maximal surface utilization and seamless electronic coupling at the heterointerface. This architecture generates densely distributed electromagnetic hotspots within densely packed interparticle regions, while concurrently engineered oxygen vacancies establish low-barrier charge-transfer pathways that facilitate resonant photoinduced electron transfer between substrate and analyte molecules. The synergistic interplay between maximized plasmonic coverage and vacancy-mediated interfacial charge transport delivers an enhancement factor of 2.46 × 10 8 with detection limits down to 10 −10  M for Rhodamine 6G. Beyond sensitivity, intrinsic photocatalytic activity imparts self-regenerating capability, enabling complete degradation of residual analytes under UV irradiation within 30 min and sustaining reproducible performance over multiple detection cycles. Reliable quantification in river water matrices confirms practical viability for trace contaminant analysis. This work establishes oxygen-vacancy-mediated interfacial engineering-coupled with conformal plasmonic integration-as a transformative strategy for transforming a widely available perovskite into a high-performance, reusable SERS platform, advancing the design of intelligent sensing materials through synergistic heterointerface optimization. Download: Download high-res image (136KB) Download: Download full-size image