Influence of Gd-doping on physical properties of Zn_1-xyNi_yGd_xO nanoparticles and its antibacterial activity

High purity Ni and Gd co-doped ZnO nanoparticles were synthesized by the chemical precipitation method and their structural, optical and antibacterial activity has been investigated using EDX, SEM, UV–Vis analysis, XRD and inhibition zone assay. The prepared nanoparticles have a lower band gap than the bulk ZnO. The red-shifted band gap was observed due to the addition of the dopant Gd. High refractive index has been observed at high Gd doping concentration. The prepared nanoparticles were of p-type in nature and the hole concentration increases as the doping concentration of Gd increases. The structural properties investigated by the X-ray diffraction technique reveal the formation of a hexagonal wurtzite structure. The change in crystallite size from 33 to 62 nm with simultaneous decrease in texture coefficient from 1.23 to 1.20 was observed when the Gd doping concentration increases from 0 to 15%. The prepared nanoparticles have been found to have antibacterial activity against Escherichia coli and Staphylococcus aureus and the doping did not enhance the activity against Pseudomonas aeruginosa. (author)