Trace-Level Detection of Explosive Molecules with Triangular Silver Nanoplates-Based SERS Substrates

Abstract

We report a simple route to design highly sensitive triangular silver nanoplates (TSNPs)-based SERS substrate for the trace-level detection of explosive molecules. The size-dependent localized surface plasmon resonance (LSPR) tunability for the synthesis of TSNPs is achieved by controlling reaction kinetics and seed volume in a modified seed-mediated approach. The computed extinction spectra of TSNP, using the finite-difference time-domain (FDTD) method, are in excellent agreement with the experimental results, therefore assisting further in the investigation of the plasmonic properties of TSNP. The higher electric field enhancement offered by TSNP is systematically investigated by performing the FDTD simulations for various sizes and corner rounding of TSNP. The FDTD results show that the dipolar plasmon resonance wavelength, size, and corner rounding of TSNP are the principal contributing factors for designing the high-performance SERS substrate. Herein, we have used a portable Raman system for the SERS-based detection of three important explosive molecules: picric acid (PA), ammonium nitrate (AN), and 2, 4-dinitrotoluene (DNT). The TSNP-based SERS substrates display excellent intensity enhancement factors of\u2009~\u2009107 for rhodamine 6G (R6G) and PA and\u2009~\u2009105 for AN. The high sensitivity of SERS substrate with limit-of-detection (LOD) of value 2.3\u2009×\u200910−11 M for PA and 3.1\u2009×\u200910−8 M for AN and effective batch-to-batch reproducibility for DNT, thus offering its potentials for field detection of explosive molecules at trace-level.