Role of Ag Nanoparticles on Photoluminescence Emissions, Antibacterial Activities, and Photocatalytic Effects in ZnO-Ag Nanocomposites Synthesized via Low Temperature Green Synthesis Method Using Azadirachta Indica Leaf Extract

A facile synthesis of ZnO-Ag nanocomposites (NCs) and their photoluminescence (PL), antibacterial and photocatalytic activities have been reported. Three different samples of ZnO-Ag NCs were prepared by varying the amount of biogenic Ag nanoparticles (NPs) in a fixed concentration of ZnO NPs. The formations of NC along with its associated properties were confirmed through various contemporary characterisation techniques. An enhancement of the ultraviolet PL emission with a corresponding reduction of visible PL emission was found with increase in the content of Ag in the NCs. Result of antibacterial assay showed that ZnO-Ag NCs were more efficient to perform antibacterial effects for Gram-negative bacteria than the Gram-positive bacteria. It was also observed that the NC having higher amount of Ag exhibited better antibacterial effects for both types of bacteria. The excellent photocatalytic activity was also observed for the NCs showing the highest antimicrobial effects among the samples.