ZnO 나노 입자에 대한 Capping agent의 효과와 특성에 관한 연구

Abstract

ZnO nanoparticles have been intensively used as a multifunctional material suitable for a variety of applications due to its unique electrical and optical properties and high chemical stability. They are considered as important functional oxide nanostructures in a wide area of high-technology applications, e.g. surface acoustic wave filters, ultraviolet laser devices, photonic crystals, photo detectors, field-emitting devices, sensors, piezoelectric materials, and solar cell electrodes. ZnO nanoparticles can be synthesized by various approaches including sol？gel processing, homogeneous precipitation, mechanical milling, organometallic synthesis, microwave method, spray pyrolysis, thermal evaporation and mechanochemical synthesis. However, ZnO nanoparticles are prone to aggregate due to the large surface area and high surface energy. In order to improve the dispersion, it is necessary to modify the surface of ZnO nanoparticles. Some researches have revealed several physical and chemical methods for modifying the surface of ZnO nanoparticles. The chemical surface modification, which can be classified as surface grafting and esterification, is the most promising method because of the strong covalent bond between the surface modified particles and polymer chains. Various elements has been reported to affect its electrical and optical properties. ZnO is an environment friendly material, which is desirable especially for bioapplications. Due to the increasing demands globally for green materials and processes, new and efficient synthesis processes are desired. A large number of techniques like spray pyrolysis, thermal decomposition, chemical vapour deposition, laser ablation, etc. have been used for synthesis of nanomaterials and structures. Chemical synthesis is one of the important techniques which can be performed using a range of precursors and synthesis conditions like temperature, time, concentration, pH of reactants, etc. Optimization of these parameters leads to nanoparticles of different size, shapes and showing different optical properties. In this study, ZnO nanoparticles are synthesized by wet chemical method, which is a simple method, under ambient atmosphere at room temperature. During synthesis, five capping agents : Triethanolamine(TEA), Oleic acid, Tetraethyl orthosilicate(TEOS), Mercaptosuccinic acid(Ms) and 3-amino propylmethoxysilane(Am)were used and effect of concentrations was analyzed for their effectiveness in limiting the particle growth. The obtained particles were characterized by XRD, FE-SEM, TEM and UV-VIS. In this study, TEA acts as a more effective capping agent than other things.