Tailored nanocones arrays on cellulose fiber: A higher-performance flexible SERS substrate for trace chemical detection

Abstract

This study presents the successful fabrication of silver nanocone surface-enhanced Raman spectroscopy (SERS) substrate on flexible 70 GSM paper using the Direct Current (DC) magnetron sputter deposition technique. XRD analysis confirmed the crystalline nature and face-centered cubic structure of the Silver Nanocone (AgNC) substrate. SEM analysis revealed the fabricated AgNC substrate shows nanocones arrayed on the cellulose fibers. UV–visible spectral analysis validates the surface plasmon resonance peak of the AgNC substrate at 406 nm. Furthermore, SERS spectral analysis showed excellent detection abilities by accurately identifying rhodamine 6G and methylene blue dyes and fipronil pesticides at concentrations of 10−9 M, 10−8 M, and 10−6 M respectively. In addition, the substrate detects fipronil (pesticide) sprayed on tomatoes and nicotine (energy booster) mixed with tea for commercial applications. The substrate exhibits enhancement factor values for rhodamine 6G, methylene blue, fipronil, and nicotine as 1.3 × 107, 1.2 × 106, 2.6 × 105, and 5.8 × 104, respectively. Theoretical validation using density functional theory confirms the experimental Raman and SERS peaks show good similarity. Considering that the charge transfer mechanism shown in the study of the frontier molecular orbitals allowed for the identification of the interaction between the analyte molecules and silver cluster. The fabricated SERS substrate exhibited remarkable stability and reproducibility.