Solution growth and characterization of ZnO nanostructures

• Main Author: Koh, Xue Li
• Other Authors: Dong Zhili
• Format: Final Year Project
• Language: English
• Published: 2014
• Subjects: DRNTU::Engineering::Nanotechnology
• Online Access: http://hdl.handle.net/10356/55798
• Institution: Nanyang Technological University

Porous ZnO nanostructures developed via low temperature hydrothermal synthesis mostly require high temperature annealing (>400 °C) for significant amount pores to form. The use of such high annealing temperatures induces high costs and hazards.. Hence, in order to simplify the development of porous ZnO nanostructures, this project aims to develop a one-step process for the growth of ZnO nano-flakes. This is done with hydrothermal synthesis at 200 °C. Although impure ZnO nanostructures are obtained when the reaction time is set at 24 h, when the reaction time is increased to 72 h, pure ZnO nano-flakes can be obtained. Large pore density is observed in as-synthesized ZnO nano-flakes with high temperature synthesis. Hence in this report, a simple, single step synthesis of ZnO nano-flakes may be achieved. With annealing, porosity is observed to decrease and the probable reason for this is increased grain growth. Porous ZnO nano-flakes have gained great interest as it performs better than ZnO non-porous nanostructures and porous nano-rods. It has been reported to have greater sensitivity to gases and higher conductivity due to its high surface area. It also has many potential applications such as photoelectronic optical devices, gas sensors, photocatalysts etc.