Hollow Multi-Shelled V2O5 Microstructures Integrating Multiple Synergistic Resonances for Enhanced Semiconductor SERS

Enhancement of the light-matter coupling is a promising approach to improve the sensitivity and universality of semiconductor-based surface-enhanced Raman scattering (SERS). Herein, it is demonstrated that hollow multi-shelled V 2 O 5 microstructure can be utilized as an active substrate to integrate multiple synergistic contributions. The experiments and numerical simulations clearly reveal that the excellent SERS activity originates from the unique double-shelled hollow structures, which allow multiple reflections of electromagnetic waves. This light-trapping effect provides an efficient resonance absorption for charge-transfer (CT) and exciton enhancements. More importantly, the coupling of outer and inner shells remarkably generates high electric field contribution for SERS enhancement. Besides, the symmetry analysis of vibrational modes based on density functional theory well explains the origin of the CT coupling of Herzberg–Teller selection rules. The synergy of all factors contributes to a significant increase in the sensitivity and universality of semiconductor SERS. It is anticipated that the strategy demonstrated in this study will widen the scope of currently available methodologies for designing substrates with high semiconductor SERS activity.