Nonstoichiometric tungsten oxide nanosheets with abundant oxygen vacancies for defects‐driven SERS sensing

Abstract

AbstractSemiconductor materials have gradually developed into attractive candidate substrates for surface‐enhanced Raman spectroscopy (SERS) due to their unique characteristics, exhibiting great application potential in a wide range of scenarios. The introduction of oxygen vacancies plays a key role in improving the performance of semiconductor substrates by effectively modulating the surface state and electronic structure of semiconductor materials. Here, a reduction method is employed to prepare nonstoichiometric WO3−x nanosheets with abundant oxygen vacancies, which as a substrate material possesses excellent SERS sensing performance and outstanding signal reproducibility. The presence of surface deficiency sites generates an effective photoinduced charge transfer resonance at the interface between the substrate and the analyte molecules by offering more charge transfer pathways as well as strong vibration coupling, thereby achieving significantly improved SERS sensitivity on the WO3−x substrate. Further investigations suggest that the defect structure is beneficial to facilitate the recognition of multiple probe molecules, which indicates semiconductor materials have great potential in SERS detection.