Papers by Author: Javad Samei

Abstract: Current researches show a growing interest in Zinc Oxide (ZnO) nanoparticles. ZnO is a semiconductor with a wide direct band gap of 3.37 eV and a large exciton binding energy of 60 meV at room temperature. Several methods have been developed in order to synthesize ZnO nanoparticles. Chemical methods, among them sol-gel process, are more convenient. Sol-gel is common for producing metal oxide nanoparticles because of its simplicity, cheapness and high quality products. In this research ZnO nanoparticles were prepared via the sol-gel process. ZnAc2.2H2O as precursor and TEA (Triethanolamine) as a novel surfactant were used in a methanolic solution. MEA (Monoethanolamine) and DEA (Diethanolamine) have been highly used before. In this research, solutions with different weight ratios of ZnAc to TEA (1:2, 1:1 and 2:1) were obtained. After drying, all samples were calcinated at 500 °C for 1 hr. Obtained nanoparticles were characterized with the hope of achieving better properties.

Abstract: ZnO as a semiconductor is used in many applications such as gas sensor devices, laser and optoelectronic devices, photocatalysts, solar cells, and varistors. The applications and properties of ZnO nanoparticles highly depend on the size and morphology of these particles. In this research ZnO nanoparticles were prepared via chemical bath deposition at various temperatures in order to see the effects of synthesis temperature and also 2- methoxyethanol (2-ME) as a novel solvent on the morphology of obtained nanoparticles. For synthesizing of ZnO nanostructured materials, 2-ME has been highly used in sol-gel process but it is the first time that it is used in the chemical bath deposition process. For this purpose 1 M solutions of zinc acetate dehydrate in 2-ME were prepared and added to the solution of NaOH in the same solvent dropwisely. Monoethanolamine (MEA) was used as surfactant. The synthesis temperatures were 30°C, 60°C and 90°C. After filtering and drying, morphologies of obtained nanoparticles were characterized and compared.