Effect of silver doping on structural, optical and antifungal properties of copper oxide nanoparticles prepared using Colocasia esculenta leaf extract

Abstract

Copper oxide (CuO) nanoparticles have attracted significant interest for their diverse applications. This study focused on the eco-friendly synthesis of undoped and silver (Ag) doped CuO nanoparticles using Colocasia esculenta leaf extract. XRD analysis revealed a cubic crystal structure in Ag doped nanoparticles with reduced crystallinity compared to undoped counterpart. FTIR spectra confirmed the efficient encapsulation of plant extracts and significant microstructural modification due to doping. Both undoped and Ag-doped CuO nanoparticles exhibited distinct optical property, characterized by a consistent direct band gap energy of 5.3 eV. Ag-doped CuO nanoparticles demonstrated a higher negative zeta potential (-29 mV) and smaller particle size (98.5 nm), resulting in a stable colloidal dispersion with lower polydispersity index. Morphology revealed reduced agglomeration and smaller grain size in doped CuO nanoparticles, leading to more uniform, spherical particles as confirmed by EDX, which indicated the successful inclusion of Ag ions in the CuO lattice. Furthermore, Ag doping significantly enhanced antifungal activities of CuO nanoparticles (p<0.01). The increased generation of reactive oxygen species led to greater microbial cell damage and higher inhibition zones, with a maximum inhibition of 28 nm and 27 nm against Botrytis cinerea and Phoma medicaginis, respectively at a concentration of 250 µg/ml. Hence, the study highlights the potential of green synthesized CuO nanoparticles, especially Ag-doped variants, as effective antifungal agents. Their versatile properties make CuO nanoparticles as a promising candidate for a wide range of applications in biomedicine and agriculture.