Green synthesis, characterization of Au–Ag core–shell nanoparticles using gripe water and their applications in nonlinear optics and surface enhanced Raman studies

Abstract

In recent years there has been excessive progress in the 'green' chemistry approach for the synthesis of gold and silver nanoparticles. Bimetallic nanoparticles have gained special significance due to their unique tunable optical properties. Herein we report a facile one-pot, ecofriendly synthesis of Au-Ag bimetallic core-shell nanoparticles using gripe water as reducing as well as stabilizing agent. The as-synthesized Au-Ag nanoparticles are characterized using UV-Vis spectroscopy to determine the surface plasmon resonance, and using transmission electron microscopy to study the morphology and the particle size. The optical nonlinearity of the bimetallic nanoparticles investigated by z-scan technique using femtosecond Ti:sapphire is in the order of 10 9 . The nonlinear optical parameters such as the nonlinear refractive index n 2 , nonlinear absorption coefficient β and the third order nonlinear susceptibility χ 3 are measured for various wavelengths from 700 nm to 950 nm. The Au-Ag nanoparticles are also used in surface enhanced Raman spectroscopic studies to enhance the Raman signals of rhodamine 6G.

Synthesis and characterization of silver nanoparticles from Alpinia calcarata by Green approach and its applications in bactericidal and nonlinear optics

“…This method was developed by Sheik-Bahae et al [36], to measure the sign and magnitude of nonlinear refraction n 2 of a material [37]. The beam from 532 nm Nd:YAG (CW) laser was focused using 3.5 cm lens.…”

“…inferred from the open aperture z-scan[37][38][39].The real and imaginary parts of the second order hyperpolarizability, γ, of the solutes were computed assuming additivity of the nonlinear contributions of the solvent and the solute and the applicability of the Lorentz local field approximation[40]. The optical nonlinear parameters are obtained from equations where is the nonlinear refractive index, k is the wave number (k=2π/λ) and ∆Φ 0 is the onaxis phase shift at the focus, I 0 is the peak intensity within the sample at the focus, L eff is the effective thickness of the sample (1 mm-quartz cuvette), S is the linear aperture transmittance (0.5) andis the normalized peak valley difference obtained from theclosed aperture z-scan trace, ∆T=1− , where is the normalized peak value from the open aperture plot [38-40].…”

Core@shell Nanoparticles: Greener Synthesis Using Natural Plant Products

“…Venkateswarlu et al [39] reported two-step biosynthesized Fe 3 O 4 -Ag core/shell NPs (50 nm) using Vitis vinifera stem extract. Au-Ag core shell NPs (10 nm) were synthesized via one-pot method using grape water [40], a herbal medicinal drug. Plants seem to be the ideal candidates as they are suitable for expeditious large-scale green synthesis of core-shell NPs; the rate of synthesis being faster than those observed for processes aided by microorganisms [41].…”

Synthesis of Au, Ag, Curcumin Au/Ag, and Au-Ag Nanoparticles and Their Nonlinear Refractive Index Properties

“…Ag/Au (core/shell) nanoparticles were prepared using gripe water according to the procedure given in [15]. In a flask, 2 mL of 0.3 mM AgNO 3 was mixed with 10 mL of gripe water.…”