An environmentally friendly green synthesis of Co2+ and Mn2+ ion doped ZnO nanoparticles to improve solar cell efficiency

Global warming is a threat to human health in the context of increasing organic or inorganic pollutants, which are produced by various products. The “Green synthesis” method effectively eliminates toxic and/or harmful effects that arise due to the wet-chemical synthesis process. Different concentrations of Co2+ and Mn2+ ion doped ZnO-nanoparticles (NPs) were designed at a low temperature, about 70 °C by utilizing an eco-friendly sustainable method with dandelion leaf (DL) extract as a solvent and these biosynthesized NPs were annealed to grow the crystallinity enhancement. The confirmation of NPs crystal phase, phase purity, and grain size was performed by XRD, showing the hexagonal-Wurtzite phase structure. SEM and TEM images of the NPs demonstrated sub-100 nm spherical-shaped particles. Fourier transform infrared displays characteristics band about ∼523 cm–1 which corresponds to Zn–O tetrahedron asymmetric stretching vibrations. Both UV-Visible and luminescence studies confirmed the adjacent band edge emission of ZnO and successive incorporation of Co2+ and Mn2+ ion-doped ZnO host. For improving power conversion efficiency, the polycrystalline silicon solar cells (PSSCs), different layers of Co2+ and Mn2+ ion-doped ZnO-NPs coated on bare PSSCs are promising strategies. Additionally, solar cell efficiency decreases with further coating of NPs layers and/or thickness. Optimum solar cell efficiency was observed for 5 at% Mn2+ ion-doped ZnO-NPs with three layers. Finally, Radish and Cress plants are grown, using the biosynthesized ZnO-NPs supernatant from DL extract, which showed high environmental biocompatibility.