Extracellular bio-synthesis of silver nanoparticles

The effect of cetyltrimethylammonium bromide, CTAB has been studied on the optical properties and morphology of advanced Ag-nanoparticles (AgNPs) using Oriental plane leaves extract as a reducing-, stabilizing- and capping-agent for the first time. The formation of Ag-nanodisks was monitored by measuring the UV-vis spectra at different time intervals (5, 10, 20 and 30 min) after adding the leaves extract (from 1 to 5 cm3) to the different AgNO3 solutions ([Ag+] = 4.0, 8.0, 12.0, 16.0 × 10−4 mol dm−3). The sigmoidal nature of the reaction-time plots suggests the involvements of an autocatalytic reaction path. In the presence of CTAB, the peak at 450 nm is shifted to shorter wavelength, i.e., 425 nm and sharpness of the surface resonance plasmon (SRP) band also decreases. The results confirm a significant change in the morphology and/or agglomeration tendency with CTAB. Transmission electron microscopy (TEM) results show the formation of stable AgNPs at different concentration of AgNO3 gives mostly spherical particles with diameter ranging from 10 to 30 nm.