Structural and optical studies of colloidal silver nano particles

Abstract

Colloidal silver nano particles are prepared by biosynthesis using medicinal plants like Ocimum Sanctum and AdhaThodaVasica. Soft gamma ray irradiation is done on the samples. Transmission electron microscopic image of before irradiated silver nano colloid shows the agglomeration of spherical nano clusters while the irradiation results in the reduction of particle size with well defined grains. Selected area electron diffraction studies can explain both the polycrystalline pattern of silver nano colloids. Further, the crystal structure is identified as Face Centered Cubic pattern. The formation and stability of silver nano particles in the colloidal solutions are monitored using uv–visible absorption spectra. Gamma irradiation does not change the band gap value of nano silver. Here the plant extracts served not only as reducing agents but also a good stabilizing agent, which prevents the aggregation of silver nano particles. Gamma ray irradiation helps a better confined morphology for silver nano particle without affecting the structural parameters and optical band gap values.