Green engineering of optical band gap in plasmonic silver quantum dots using allium cepa extract.

Silver quantum dots are prepared from aqueous AgNO3 solution by employing biological reduction using allium cepa extract under different compositions. The prepared quantum dots were analyzed experimentally by employing UV -visible Spectroscopy, HRTEM and FTIR techniques. The observed change in colour of mixture with composition is analyzed in detail. UV-visible experimental data was employed to calculate the optical band gap of different samples. Effective engineering of optical band gap is achieved by method of green synthesis. HRTEM analysis clearly indicated the formation of quantum dots through particles of spherical shape with average size of 10 nm. Crystallization of the obtained particles is confirmed as FCC of silver.FTIR measurements were carried out to identify the possible biomolecules responsible for capping and efficient stabilization of the Ag metal nanoparticles in the present study. [ABSTRACT FROM AUTHOR]