Investigating the Formation Mechanism of ZnO Nanoparticles using Plant Extracts: A Review

Nanotechnology is an emerging field of science that concerns the industrial use of nanoparticles (NPs), of the size ranges between 1 to 100 nm, which are classified into different classes such as inorganic, organic, ceramic and carbon-based nanoparticles. Zinc oxide (ZnO) NPs is utilized in numerous applications due to their vital properties (please mention which properties, or what these properties are important for) and hence it will be the focus for this review. Because producing NPs using chemically and physically is often expensive and potentially harmful to both the environment and the user, there has been an increasing interest in using biological or green methods to produce metal and metal oxide NPs. Recently, the researchers started to utilize green synthesis methods for producing different NPs, however, the NPs formation mechanism using plant extracts are still under investigation. Consequently, more in-depth studies are needed on how NPs are formed in plant extract medium. This review is designed to highlight the most robust mechanisms of formations ZnO NPs using plant extracts and to cover the commonly used plants for synthesizing ZnO NPs over the last fourteen years. This review will also help researchers to understand the proposed formation mechanisms of the NPs synthesis using plant extracts And to identify the gaps in the knowledge in this field.