Studies on structural and optical properties of co-doped metallic ZnO NPs

AbstractsThe development of co-doped metallic oxide nanostructures with tailored optical and electronicfunctionalities represents a significant advance toward multifunctional catalysts andoptoelectronic devices. In this study, Cd-doped and Al/Ag co-doped ZnO nanoparticles (NPs)were synthesized via a sol–gel route to investigate the influence of dopant interaction onstructural and optical properties. The as-prepared samples were characterized using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), and UV–Vis spectroscopy. XRD patterns confirmed the formation of a single-phase wurtzite ZnO structure with reduced crystallite size upon co-doping, while EDSvalidated the incorporation of Cd, Al, and Ag ions within the ZnO lattice. FESEM imagesrevealed homogeneously distributed, quasi-spherical nanoparticles with reduced agglomeration.Optical absorption spectra exhibited a pronounced blue shift in the UV region with increasingco-dopant concentration, corresponding to a widening of the optical band gap from 3.02 eV (Cd–ZnO) to 3.07 eV (Ag–Al/Cd–ZnO). This enhancement is attributed to lattice strain, sizequantization, and the Burstein–Moss effect. These results indicate that Al/Ag co-dopingeffectively modulates the band structure of ZnO, improving its potential for UV–visible light–driven photocatalysis and advanced optoelectronic applications.