Colorimetric investigations and optical properties of Co-doped ZnO nanopigments prepared by gelatin-based sol-gel method

In this study, we present the synthesis, characterization, and colorimetric analysis of Zn1-xCoxO nanopigments (x=0.0: ZnO, x=0.02: ZC2, x=0.04: ZC4, x=0.06: ZC6, and x=0.08: ZC8), where cobalt (Co) is doped into the zinc oxide lattice. The nanopigments were synthesized using a gelatin-based sol-gel method, ensuring uniform incorporation of cobalt ions into the ZnO lattice. Structural characterization, including X-ray diffraction (XRD) analysis, showed minimal changes in the hexagonal structure of ZnO with the addition of cobalt impurities. Crystallite size analysis using the Size Strain Plot (SSP) method indicated an increase in crystal size with cobalt doping. UV-Vis spectroscopy confirmed the impact of cobalt on the absorption edge and reflectance spectra of the nanopigments. Colorimetric analysis revealed a shift towards green hues with increasing cobalt concentration, although the relationship between cobalt content and color intensity was nonlinear. These findings offer valuable insights into the synthesis, structural properties, optical behavior, and color characteristics of Co-doped ZnO nanopigments, highlighting their potential for various industrial applications.