Zinc oxide nanoparticles (ZnO NPs) are of great interest from
both academic and technological viewpoints owing to the unique
physical and chemical properties [1]. Great demand and large
production of ZnO NPs have however led to environmental concern
and an urge for greener synthesis strategies [2]. Among
techniques available for the synthesis of ZnO NPs, e.g. thermal
decomposition [3], sonochemical synthesis [4] and sol-gel [5], the
microwave synthesis has appeared as the most promising platform
for green and economic synthesis [6–8]. The technique was reported
to provide excellent phase purity and uniformity in particle
shape and size with a reduction in reaction time [68]. In the
microwave syntheses, the use of environmentally hazardous reagents
was however unavoidable [9]. The alternative choices of
natural reagents will make the process greener