Effect of pH on the morphology and optical properties of modified ZnO particles by SDS via a precipitation method

ZnO particles were synthesized directly from an aqueous solution of zinc acetate dihydrate in the presence of sodium dodecyl sulfate (SDS) and sodium hydroxide at 70 °C. The morphological changes were investigated in the range of pH 8–12. The hexagonal prism-like shape was formed at pH 8 and 10 by inhibition of growth along the c direction whereas the small rod-like shape was observed at pH 12. The estimated band gap and the room temperature photoluminescence intensity in a visible region are dependent upon the geometrical shape and size of the ZnO particles.

The hexagonal prism-like shape is observed at pH = 8 and 10 on the other hand the small rod structure is found at pH = 12. The changing of morphology can be explained by interaction between SDS and growth unit. The stabilized Zn(OH)2 by SDS molecules probably inhibits the ZnO formation which can be confirmed by the FT-IR results. This evidence fulfills with the reason why the rate of ZnO formation is too slow at low pH.Figure optionsDownload as PowerPoint slide