Control repeatability synthesis of a new structure: nanoyarn in green synthesis of 3D ZnO NCs and its thermal time influence on optical properties

This study offers a green synthesis of zinc oxide nanocrystals (ZnO NCs) using natural salvia officinalis (SOL) leaves extracted without the need for chemical surfactants from a bottom-up approach. The ZnO NCs have been fabricated through a thermal chemical solution deposition (CSD) route at 85 °C on a glass substrate. FESEM images show the repeatability of a three-dimensional (3D) ZnO NCs nanoyarn-like structure versus reaction time variation that is assembled by many uniform ZnO of crescent-shaped nanoslices and nanoplates. The X-ray diffraction (XRD) profile exhibits a positive correlation between crystallinity and reaction time. The optical properties of the SOL/ZnO NCs represent the UV–vis absorption in the blue region with a bandgap (E_g) of 2.16 eV and a high photoluminescence (PL) emission intensity with a peak at 572.7 nm and yellow–red shift emission after a 16-h reaction time. The ability to fabricate SOL/ZnO NC nanoyarn-like structures repeatedly using an eco-friendly green synthesis of natural SOL phytochemicals with excellent optical properties is encouraging for future photovoltaic applications.