Sylvia Opiyo

1 Introduction Zinc oxide (ZnO) is among promising materials with advanced applications due to its wide bandgap energy (3.37 eV) and a binding energy of 60 meV [1]. The applications of its nanoparticles (NPs) include electronics and optoelectronics, photocatalysts, biomedical applications, cosmetics and skincare, gas sensors and antimicrobial coatings [2-6]. These applications are achieved due to their outstanding electronic and optoelectronic properties.