Effect of gold ion concentration on size and properties of gold nanoparticles in TritonX-100 based inverse microemulsions

Tokeer Ahmad,Irshad A Wani,Jahangeer Ahmed,Omar A Al-Hartomy

doi:10.1007/s13204-013-0224-y

Tokeer Ahmad, Irshad A Wani + Show 2 more

https://doi.org/10.1007/s13204-013-0224-y

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Abstract

Gold nanoparticles have been prepared successfully using TritonX-100 inverse microemulsion at different concentrations of HAuCl4 (0.1, 0.05, 0.04, 0.03, 0.02 and 0.01 M). We have studied the effect of gold ion concentration on the particle size, morphology, surface area and optical properties of the gold nanoparticles. The gold nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, UV–Visible spectroscopy and Brunauer–Emmett–Teller surface area analysis. X-ray diffraction studies show the monophasic nature of the gold nanoparticles. TritonX-100 stabilized gold nanoparticles were appeared to be agglomerated at higher concentrations (0.1 and 0.05 M) of Au3+ with an average grain size of 60 and 50 nm, respectively. Monodisperse and uniform gold nanoparticles with well-defined morphologies of an average grain size of 15 and 25 nm were obtained at lower concentrations (0.01 and 0.02 M). UV–Visible spectroscopy shows the characteristic surface plasmon resonance peak ~540 nm along with the peaks at shorter and longer wavelengths may be due to the higher order plasmon resonance of the gold nanoparticles. The surface areas of the gold nanoparticles were found to be in the range of 5.8–107 m2/g which were well in agreement with the electron microscopic studies.

Highlights

The basic research in nanoscience deals with the synthesis of nanoparticles of controlled size and morphology
We have studied the effect of gold ion concentration on the particle size, morphology, surface area and optical properties of the gold nanoparticles
The gold nanoparticles were characterized by X-ray diffraction, transmission electron microscopy, UV–Visible spectroscopy and Brunauer–Emmett–Teller surface area analysis

Summary

Introduction

The basic research in nanoscience deals with the synthesis of nanoparticles of controlled size and morphology. The properties of the nanomaterials originated primarily because of quantum confinement of free electrons, large surface to volume ratio and highly disordered arrangement of dipoles at the surface as compared to their bulk counterparts (Colvin et al 1994; Alivisatos 1996). The nanoparticles find applications in optoelectronics (Colvin et al 1994; Gracias et al 2000), solar cells (Kamat et al 1998), catalysis (Valden et al 1998), nonlinear optical (Yoffe 1993) and photoelectrochemical devices (Mansur et al 1995). Gold nanostructures have been extensively investigated because of their size and shape dependant surface plasmon related optical properties (Burda et al 2005). Gold nanostructures exhibit applications in chemical inertness, biological compatibility, optical switches and molecular labeling where phenomena such as Surface Enhance Raman Scattering (SERS) can be exploited (Niemeyer 2001). Gold nanoparticles have been used as contrast agents for optical coherence tomography (Chen et al 2005), radiosensitizers (Chithrani et al 2010), in

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