Effect of Anionic Amphiphiles on the Morphology of Hexagonal Plate-like ZnO Particles

Abstract

IntroductionZinc oxide ZnO is a well-known semiconductor used in photocatalysis to decompose organic compounds 1 6 and in electronic devices 7 11 , as it generates holes and electrons under UV irradiation. The crystallinity and particle size of ZnO significantly influence its properties. Thus, methods of controlling the crystal growth and morphology of ZnO have been investigated. One of the most favorable morphologies is the one-dimensional morphology, including the rod-like shape 12 14 , since in this case, ZnO grows preferentially in the c-axis direction because of the thermodynamic stability of the crystal. The crystallinity, particle size, morphology, and orientation can be controlled by varying the reaction conditions, such as the species of zinc oxide precursor, pH, reaction time, reaction temperature, and additives. Thus, variously shaped ZnO particles can be obtained, such as tubes 15 17 , tetrapods 18 21 , and flower-like particles 22 25 .Because surfactants form various self-assemblies, they are often used as additives for the synthesis of inorganic materials. Mesoporous materials 26 28 with highly ordered pore structures can be fabricated using self-assemblies of a surfactant as a template. Syntheses of mesoporous silica 26 30 , titania TiO 2 31 36 , and zirconia ZrO 2 37 39 have been re-