Daily-life candidates as flexible SERS substrates for pesticide detection: a comparative study

Abstract

Flexible surface-enhanced Raman scattering (SERS) substrates possess additional advantages over conventional solid substrates because of their capability to conform to real surfaces having arbitrary shapes which consequently improves the trace collection efficiency. However, the high-cost and cumbersome pre-requisite template preparation method is a major bottleneck for their use in real-world applications. In this study, we systematically explore cheaper and commonly available daily-routine materials like A4 printing paper, sandpaper, Al foil, crumbled Al foil, and carbon and scotch tapes directly utilizing them as SERS pre-templates. Inherent roughness of the deployed material directly serves the purpose of reducing the patterning fabrication cost by a considerable amount. However, SERS behaviors of all the above templates are investigated by depositing a requisite plasmonic active Au-Ag alloy nanolayer of identical thickness over them. By using Rh6G dye and methylene blue as detecting molecules, Raman responses of all the samples are compared. Interestingly, crumbled Al foil exhibits a significantly higher and sharp Raman response for both the analytes among all templates. In addition, pesticide detection with varying concentrations was performed on this proposed substrate. An enhancement factor of 6.36×107 is observed over crumbled Al foil in comparison with conventional bare Si. We believe this study facilitates the way of designing cheaper and ready-to-use SERS substrates for on-field detection application and will help in bringing out laboratory-like results for industrial applications without the need of any cost-intensive fabrication methods.