The effect of surfactants on the morphology and optical properties of precipitated wurtzite ZnO

Wurtzite ZnO crystals were prepared in aqueous solutions with additive-free and additives of sodium dodecyl sulfate (SDS), hexamethylenetetramine (HMT), cetyltrimethylammonium bromide (CTAB), and CTAB/SDS. In all cases, the obtained crystals exhibited the crystal structure of wurtzite ZnO and photoluminescence at UV and yellow regions. The ZnO crystals grown in the HMT solution have a morphology of aggregated rods. In the CTAB solution, rods and nanoparticles of ZnO crystals are obtained and their sizes are smaller than those obtained in other solutions. A unique morphology of aggregated nanosheets was observed for ZnO crystals grown with the mixture of CTAB/SDS. The origin of morphology difference of the ZnO crystals is explained by a chemical interaction between surface of ZnO seed crystal and ionized additives.