In Situ Detection of Organic Pollutants in Multiphase Solution Using Surface-Enhanced Raman Spectroscopy with PDMS/Grating/CuO NWs/Ag NP Multiscale Structure

Recently, multiscale cavity arrays have drawn significant attention due to their excellent optical capturing capability. Here, we successfully constructed a grating microcavity with a nanowire structure that the nanoscale copper oxide nanowires (CuO NWs) with silver nanoparticles (Ag NPs) introduced into the micrometer grating structure, which can provide a large surface area and high-density "hot spots", with the ability to couple with incident light to excite multiscale cavity modes. We demonstrated that the poly(dimethylsiloxane) (PDMS)/grating/CuO NWs/Ag NPs can serve as highly sensitive, homogeneous, and stable surface-enhanced Raman spectroscopy (SERS) substrates with a minimum detection of 1 × 10–11 M (rhodamine 6G, i.e., R6G) and 1 × 10–9 M (Sudan I). Furthermore, the remarkable hydrophobic properties (water contact angles: 165°) of the PDMS/grating/CuO NWs/Ag NP substrate allow it to directly detect organic pollutants in oil within a mixture of oil and water.