U66: Synthesis of Zinc Oxide (ZNO) Nanoparticles using Costus Woodsonii

The present invention refers to a green and biological method used to synthesize ZnO nanoparticles (NPs) with low band gap energy using zinc nitrate as a precursor and the aqueous leaf and bulb extracts of Costus woodsonii. In particular, zinc oxide nanoparticles with narrow bandgap energy were synthesized by first preparing an aqueous plant extract solution, wherein the plant extract was obtained from Costus woodsonii, then combining the extract with zinc nitrate hexahydrate (Zn(NO₃)₂·6H₂O), followed by heating and stirring of the extract to form a paste, and finally calcination of the paste to form the zinc oxide nanoparticles.

The invention provides green synthesis of zinc oxide (ZnO) nanoparticles with significantly reduced band gap using extracts of Costus woodsonii for visible light harvesting.