Surface-Enhanced Raman Scattering on Hierarchical Porous Cuprous Oxide Nanostructures in Nanoshell and Thin-Film Geometries.

Understanding the mechanism of surface-enhanced Raman scattering (SERS) of molecules on semiconductor nanostructures is directly related to our capabilities of designing and optimizing new SERS-active substrates for broad applications in the field of molecular detection and characterization. Here, we present an exploration of using cuprous oxide nanostructures with hierarchical porosity for enhancing Raman signals of adsorbed probe molecules. Distinct SERS signals were detected on both individual polycrystalline nanoshells and porous thin films composed of cuprous oxide nanocrystals. The observed enhancement of SERS signals can be interpreted as synergistic effects of strong chemical interactions between the probe molecules and cuprous oxide surfaces, localized electromagnetic field enhancement, and the unique hierarchical porosity of the nanostructures. Our work introduced a novel type of semiconductor substrates for high-performance SERS and extended the applications of cuprous oxide nanostructures to spectroscopy-based molecular sensing and characterizations.