Copper hydroxide nanowires assisted molecule enrichment for highly sensitive SERS detection

Abstract

Surface-enhanced Raman scattering (SERS) has been recognized as one of the most powerful spectroscopic tools for molecular detection. In the past decades, Hotspots engineering have promoted the improvement of SERS performance. Recently, molecular enrichment has proven to be another effective approach to improve SERS performance. In this work, we propose a concept of multiple filtration to increase the amount of analytical molecules, thus achieving molecular enrichment for ultra-low concentration detection. The approach combined the high Raman enhancement effect of Ag nanostructures and the multiple filtration capability of copper hydroxide nanowires (CHNs), making Ag/CHNs/Mixed cellulose esters (Ag/CHNs/MCE) complex highly sensitive SERS substrates by effectively concentrating analytical molecules in close proximity to the electromagnetic fields at the SERS-active metal surface. Using this enrichment strategy, the sensitivity of SERS is remarkably improved, and the detection limits of Rhodamine 6G and crystal violet are down to 1 × 10−13 and 1 × 10−11 M, respectively. This enrichment strategy is very robust and easy to implement, and it can potentially be exploited in various plasmonic-based molecule detection and identification techniques.