Silver Nanoparticles on Porous Silicon: Approaching Single Molecule Detection in Resonant SERS Regime

• DOI: 10.1021/jp405117p
• Publication Date: 2013-09-08T14:46:42Z
• Authors: Alessandro Virga; Paola Rivolo; Francesca Frascella; Angelo Angelini; Emiliano Descrovi; Francesco Geobaldo; Fabrizio Giorgis
• Keywords: Porous Silicon; Resonance Raman spectroscopy

Metal-dielectric nanostructures consisting of Ag nanoparticles synthesized within a mesoporous silicon matrix are exploited for single molecule detection by surface-enhanced resonance Raman scattering (SERRS). The morphology is controlled yielding plasmonic resonances in the visible-near-infrared range. Enhanced activity substrates tested using Cy3 and R6G dyes as probe molecules. Tuning particle close to electronic resonance, we demonstrate enhancements larger than 1010. Time resolved spectroscopy at very low concentration yields intensity fluctuations which can be mainly ascribed charge transfer-enhancement mediated molecules diffusion between different sites on particles.