Silver Nanoparticles: Green Synthesis & Optical Properties

The present study reports a novel green synthesis of Silver nanoparticles using environmentally benign reducing agent (ascorbic acid) and identifies their main physical and optical properties. The stabilization of Silver nanoparticles was done with capping agents like starch and gelatin. The pH of the solution was adjusted to alkaline. Heating was done using a kitchen microwave .Formation of Silver Nanoparticles was indicated by change in color which is supported by the UV absorption at 570nm. Their structural and optical properties were reported. The characterization of Nanoparticles was done by TEM and XRD. In addition to the X-ray diffraction investigations and infrared spectroscopies confirmed the single phase of the copper nanoparticles. Optical studies were carried out by depositing silver nanoparticles on glass substrate using spin coating technique. The optical properties depend upon absorption of radiations which in turn depends upon ratio of electrons and holes present in the material and also on the shape of the nanoparticles. In the present investigation it was observed that optical absorption increases with increase thickness of the film which in turn depend upon speed of spin rotor and amount of silver sol added. The optical band gap for the Nanoparticles was obtained from plots between hv vs. (αhv)2 and hv vs. (αhv)1/2.The value of Band gap came out to be around 4.2 eV which is in close agreement with the earlier reported values.