MATERIALS OF ZINC OXIDE NANOPARTICLES AND THEIR POTENTIAL APPLICATIONS: PROGRESS, CHALLENGES AND PERSPECTIVES

Extensive research in nanotechnology has been conducted to elucidate new behaviors and properties of nanoscale materials fully. ZnO nanoparticles (NPs) have gained great importance due to their distinct physical and chemical properties and are, therefore, being extensively studied to exploit these properties. This study first develops various chemical methods for the preparation of ZnO NPs, namely the mechanochemical process, controlled precipitation, sol-gel method, vapor transport method, solvothermal and hydrothermal methods, and methods using emulsion and microemulsion. In particular, the paper describes green methods of using plant extracts for the synthesis of ZnO NPs. Modifications of ZnO with organic (carboxylic acid, silanes) and inorganic (metal oxide) compounds and polymer matrices are then described. Many applications of ZnO NPs have been presented in various fields such as the rubber industry, pharmaceutical industry, cosmetics, textile industry, optoelectronics, and agriculture. The photocatalytic and various biomedical applications of ZnO are detailed. Finally, an attempt was made to explore the current challenges and future scope of synthetic methods and applications of ZnO NPs.