Synthesis of silver nanodiscs and triangular nanoplates in PVP matrix: Photophysical study and simulation of UV-vis extinction spectra using DDA method

摘要

Circular nanodiscs and truncated triangular shaped silver nanoplates have been synthesized through a seeding growth approach in polyvinyl pyrrolidone (PVP) matrix at room temperature. Seeds are prepared on reduction of silver nitrate (AgNO _3) by sodium borohydride (NaBH _4) and methyl cellulose (MC) is being used as encapsulating matrix. Colored silver sols are obtained as variable amounts of seeds are added to the growth solution containing silver nitrate, polyvinyl pyrrolidone (PVP) and ascorbic acid. Silver nanostructures are characterized using UV-vis spectroscopic and transmission electron microscopic (TEM) study. TEM studies reveal that particles are mostly circular disc and truncated triangular plate like as different amount of seeds are used in the growth solution. Simulation of UV-vis extinction spectra using discrete dipole approximation (DDA) method nicely explains the observed localized surface Plasmon resonance (LSPR) band of spherical and circular disc like silver nanoparticle.