Nanocrystalline ZnO powders in a variety of shapes were synthesized through an easy precipitation method. Zinc salts, stabilizers and precipitating agents strongly affected the formation of the ZnO structure. The band gap value depended closely upon the amount of defects in various ZnO structures. The largest band gap value of 3.228 eV was obtained from ZnO nanorods with a crystallite size of 42 nm and a relative defect parameter of 0.099. The nanocrystalline ZnO particles can damage only S. aureus.
Keywords: Precipitation, Defects, Optical properties, ZnO, Antibacteria.