Optical, structural properties and antibacterial activities of uncapped and HMT capped ZnO nanoparticles

Abstract

In this work, uncapped and HMT (hexamethylenetetramine or hexamine) capped zinc oxide nanoparticles (NPs) have been synthesized by solvothermal method followed by annealing at 200, 400 and 500°C temperatures for 2h in order to tune their antibacterial properties. Effect of annealing temperature on structural growth of ZnO nanostructure have been extensively investigated and reported the synthesis of beautiful cauliflower-like ZnO nanostructures by simply controlling the temperature. HMT capped ZnO NPs have shown enhanced antibacterial activity as compared to that of uncapped one. Changes in optical and structural properties have also been found to be occurred because of capping and thermal annealing. From the X-ray diffraction measurements it has been observed that the synthesized ZnO NPs have hexagonal wurtzite phase. Various calculations through deformation models have been used to investigate the particle sizes, stress, strain and energy density values. Moreover, calculated mean particle size of the prepared NPs using these deformation models are highly correlated with transmission electron micrograph image analyses and Williamson-Hall analyses. Strong near band edge UV photoluminescence emission has also been observed from all the samples. The synthesized ZnO nanomaterials can be used in light emitting devices as well as in antibacterial activities.