Abstract
Green synthesis of optically active silver nanoparticles (Ag) containing thin film on flexible plastic strip substrate has been carried using guava leaf extract. The properties of silver films were studied using UV–visible spectrophotometer, field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX) techniques. The silver thin films were used to detect Hg2+ ions in water with lower limit of concentration up to 20 ppm by visually observing the color change of the film from brown to cloudy white. UV–visible spectra indicated blue shift due to strong redox reaction between Ag and Hg2+ ions. Depending upon the time for the color change of the Ag films, the amount of Hg2+ ions in the water is determined. This method is found to be simple and rapid for detection of Hg2+ ions in the solution.