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 tracelevel 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 ~ 10 7 for rhodamine 6G (R6G) and PA and ~ 10 5 for AN. The high sensitivity of SERS substrate with limit-of-detection (LOD) of value 2.3 × 10 −11 M for PA and 3.1 × 10 −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.

Triangular gold nanoplates/two-dimensional nano mica platelets with a 3D lightning-rod effect as flexible nanohybrid substrates for SERS bacterial detection

“…Under excitation at a resonant wavelength of 633 nm, the electric field was confined mainly to the bottom tip of the nanoplate. 41,50 The maximum Journal of Materials Chemistry B Paper enhancement factor (|E|/|E 0 |) of single spherical gold nanoparticles was 4.72 (Fig. 1e), whereas that of a single TAuNP was 10.8 (Fig.…”

Applications of surface‐enhanced Raman spectroscopy based on portable Raman spectrometers: A review of recent developments

“…[34] In recent years, with the rapid development of nanosynthesis technology, not only spherical nanoparticles can be used as SERS substrates, but other metal nanoparticles with different morphologies have also been synthesized and used in SERS technique. [35][36][37] Surfactants are the most widely used in the synthesis of nanocolloids with special morphology. On the one hand, they can prevent the agglomeration of nanoparticles, and on the other hand, they can effectively control the formation of specific sizes and shapes of nanoparticles.…”

Recent Advances in Silver Nanostructured Substrates for Plasmonic Sensors

“…SERS has the potential to detect chemical and biomolecules at a single-molecule level [ 15 , 145 ]. Therefore, is employed in various fields, e.g., medical diagnostics [ 15 , 17 , 146 ], food safety and security [ 147 , 148 ], environmental monitoring [ 149 , 150 ] and defense and security [ 151 , 152 , 153 , 154 ]. An appropriate laser excitation induces a local intense electromagnetic field in metal nanoparticles, which enormously enhances the Raman (as well as the fluorescence) signal of the molecule adsorbed on the surface.…”