Open AccessTrace level detection of explosives and pesticides using robust, low-cost, free-standing silver nanoparticles decorated porous silicon
Author(s) -
V.S. Vendamani,
Reshma Beeram,
S. Venugopal Rao,
A. P. Pathak
Publication year - 2021
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.434275
Subject(s) - detection limit , materials science , silicon , porous silicon , picric acid , explosive detection , nanotechnology , etching (microfabrication) , nanoparticle , substrate (aquarium) , silver nitrate , raman scattering , silicone , thiram , explosive material , analytical chemistry (journal) , raman spectroscopy , optics , optoelectronics , pesticide , nuclear chemistry , chemistry , chromatography , composite material , layer (electronics) , geology , biology , agronomy , oceanography , physics , organic chemistry
We report results from our extensive studies on the fabrication of ultra-thin, flexible, and cost-effective Ag nanoparticle (NP) coated free-standing porous silicon (FS-pSi) for superior molecular sensing. The FS-pSi has been prepared by adopting a simple wet-etching method. The deposition time of AgNO 3 has been increased to improve the number of hot-spot regions, thereby the sensing abilities are improved efficiently. FESEM images illustrated the morphology of uniformly distributed AgNPs on the pSi surface. Initially, a dye molecule [methylene blue (MB)] was used as a probe to evaluate the sensing capabilities of the substrate using the surface-enhanced Raman scattering (SERS) technique. The detection was later extended towards the sensing of two important explosive molecules [ammonium nitrate (AN), picric acid (PA)], and a pesticide molecule (thiram) clearly demonstrating the versatility of the investigated substrates. The sensitivity was confirmed by estimating the analytical enhancement factor (AEF), which was ∼10 7 for MB and ∼10 4 for explosives and pesticides. We have also evaluated the limit of detection (LOD) values in each case, which were found to be 50 nM, 1 µM, 2 µM, and 1 µM, respectively, for MB, PA, AN, and thiram. Undeniably, our detailed SERS results established excellent reproducibility with a low RSD (relative standard deviation). Furthermore, we also demonstrate the reasonable stability of AgNPs decorated pSi by inspecting and studying their SERS performance over a period of 90 days. The overall cost of these substrates is attractive for practical applications on account of the above-mentioned superior qualities.