Abstract
This paper reports the rapid biological synthesis of spherical gold nanoparticles at room temperature using fresh/dry leaf extract of
Mangifera indica. This is a simple, cost-effective, stable for long time and reproducible aqueous synthesis method to obtain a self-assembly of nearly monodispersed Au nanoparticles of size ∼20
nm and 17
nm. The nanoparticles were obtained within 2
min of addition of the extract to the solution of HAuCl
4·3H
2O and the colloid is found to be stable for more than 5 months. Smaller and more uniformly distributed particles could be obtained with dried leaf extract. The nanoparticles obtained are characterized by UV–vis, transmission electron microscopy (TEM) and X-ray diffraction (XRD). Crystalline nature of the nanoparticles in the fcc structure is confirmed by the peaks in the XRD pattern corresponding to (1
1
1), (2
0
0), (2
2
0), (3
1
1) and (2
2
2) planes, bright circular spots in the selected area electron diffraction (SAED) and clear lattice fringes in the high-resolution TEM image. The possible biomolecules responsible for efficient stabilization are suggested by studying the FTIR spectrum of the sample. This environmentally benign method provides much faster synthesis and colloidal stability comparable to those of chemical reduction.