Abstract
For the application of nanocrystalline ZnO in pharmaceuticals and cosmetics, in addition to high purity, a precise control of particle size, shape and agglomeration is necessary so that transparent films with high absorption coefficients can be obtained. In this communication we report the synthesis and structure-property correlation of ZnO nanospheres and tetrapods prepared by the gas phase oxidation of zinc metal precursor. We have evaluated the ecotoxicity of the ZnO tetrapods and spheres by studying the rate of formation of reactive oxygen species using EPR spectroscopy. We find that ZnO tetrapods form reactive oxygen species, but at a rate much lower than nanocrystalline TiO2 when irradiated with UV-A