High Uniformity of ZnO Nanoparticles Synthesized by Surfactant-Assisted Solvothermal Technique

The aim of this study is to develop the synthetic procedure of Zinc Oxide (ZnO) nanoparticles by using surfactant-assisted solvothermal technique in order to produce highly uniform nanosize of ZnO particles. The solvothermal reaction evidently produces smaller ZnO particle sizes compared with those obtained from hydrothermal reaction. The zwitterionic surfactant is employed in this work and it typically works well under extremely conditions i.e. high pH levels, strong electrolytes, and high temperature. The key success of surfactant utilization in the solvothermal reaction is to create reversed micelles which act as nanoreactors or templates. Because micelle consist of polar cores that may occupy a finite amount of water forming a water pool for ZnO nanomaterial synthesis. Synthesized ZnO nanoparticles were obtained from solvothermal reaction at 180°C and 18 hours in a hydrothermal reactor. The ZnO colloidal particles were separated by paper filter and cellulose nitrate membrane, respectively. The XRD pattern shows that the structure of the synthesized ZnO nanoparticles is hexagonal wurtzite and the use of surfactant does not interfere the crystal growth and structure. The particle size distribution reveals a high uniform ZnO nanoparticles obtained via this method. The UV absorption spectrum of ZnO nanoparticles synthesized by this method presents exciton peak at approximate value of 365 nanometers. The energy band gap determined by Tauc plot is 3.31 eV. Moreover, TEM images confirm the particle size consistency showing the morphology of the prepared ZnO nanoparticles.