SILAR grown Ag nanoparticles as an efficient large area SERS substrate

Abstract

Ag nanoparticles having different size and coverage are grown on large area glass substrate (~10 cm2) using low cost successive ionic layer adsorption and reduction (SILAR) method. The SILAR parameters, such as reduction time and growth cycles are optimized to grow Ag nanoparticles with appropriate size and coverage showing maximum surface enhanced Raman scattering (SERS) enhancement of Rhodamine 6 G(R6G). For fixed growth cycles, the size and the coverage of the grown Ag nanoparticles are found to increase with the reduction time and then saturate. The size and coverage of the grown Ag nanoparticles monotonically increase with growth cycles. However, for higher growth cycles, the shape of Ag nanoparticles could not maintain their sphericity and became rock shaped/nonspherical particles, giving rise to intense quadruple plasmon resonance. The growth mechanism is proposed. Further, SERS activity of the grown Ag nanoparticles is studied for an industrial pollutant methylene blue (MB). The observed SERS enhancement factor (~109) for MB is much higher than the reported values in literature. Measured relative standard deviations values of Ag nanoparticles grown with optimum SILAR parameters suggest the excellent homogeneity and reproducibility of the SERS signal.

Spin-Coated Ag NPs SERS Substrate: Role of Electromagnetic and Chemical Enhancement in Trace Detection of Methylene Blue and Congo Red

“…Therefore the rest contribution (~ 10 2 ) is most probably from the CE mechanism which is confirmed by the observed shift in the peak position and presence of 247 cm -1 Raman peak of AgNPs@Clsurface complex in MB SERS spectra [53]. It is quite difficult to compare the obtained GSERS value with the available literature due to the fact that different MB concentrations, laser sources with different powers were used in the literature to calculate the GSERS values [16,43,54]. However it is noteworthy with low laser power (60 μW), the AgT1k SERS substrate shows excellent sensitivity (10 -10 M) and SERS enhancement (GSERS ~ 3.2×10 9 ) factor as compared with the literature.…”

“…AgT1k SERS substrate. SERS enhancement factor (GSERS) equation (see supplementary information) can be written as below [16,52],…”

“…Plasmonic metal NPs based SERS substrates gained utmost priority due to their high sensitivity and reproducibility of the SERS signal [3]. Many studies show that LSPR peak coinciding with the wavelength of incident laser produces huge local electric field in the proximity of plasmonic metal NPs [14][15][16]. Therefore, optimizing the size, shape, and interparticle distance of appropriate plasmonic metal NPs with suitable coinciding excitation source greatly enhances SERS signal.…”

Recent advances in linear and nonlinear Raman spectroscopy. Part XIII

“…Shaikh et al have grown AgNPs having different size and coverage on a large area glass substrate using the low‐cost successive ionic layer adsorption and reduction method. They report that measured relative standard deviation values of AgNPs grown with optimum successive ionic layer adsorption and reduction parameters suggest an excellent homogeneity and reproducibility of the SERS signal . Stolcova and co‐workers described gold films over very small (107 nm) spheres as an efficient substrate for sensitive and reproducible SERS detection of biologically important molecules .…”

“…They report that measured relative standard deviation values of AgNPs grown with optimum successive ionic layer adsorption and reduction parameters suggest an excellent homogeneity and reproducibility of the SERS signal. [20] Stolcova and co-workers described gold films over very small (107 nm) spheres as an efficient substrate for sensitive and reproducible SERS detection of biologically important molecules. [21] Wu et al reported both solution and solid substrates with built-in calibration for quantitative SERS applications.…”