Low-cost fabrication and morphological analysis of ZnO nanostructures: Nanorods vs. nanoflowers

The growing research interest in ZnO nanostructures stems from their outstanding electronic and optoelectronic characteristics. By precisely tailoring their morphology and lattice parameters, it is possible to fine-tune their electronic, thermal, and catalytic behaviors. However, traditional techniques for determining lattice constants are often intricate and time-consuming, underscoring the need for a simpler and more dependable approach. In this work, ZnO nanorods and nanoflowers were synthesized using hydrothermal and sol–gel methods, with their structural and morphological features verified through X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Optical reflectance spectra revealed minimal visible-light reflection (∼3–4%) and strong UV absorption, consistent with direct band gap transitions. Employing the Kubelka–Munk (K–M) model, the optical band gaps were estimated to be 3.11 eV for nanorods and 3.16 eV for nanoflowers. A simplified method for calculating lattice constants a and c from XRD data was introduced and validated against theoretical c/a ratios for the hexagonal wurtzite phase of ZnO. The obtained values exhibited excellent correlation with those from the X’Pert Highscore software-nanorods: a = 3.2319 Å, c = 5.2851 Å (software: a = 3.2499 Å, c = 5.2063 Å); nanoflowers: a = 3.2401 Å, c = 5.2911 Å (software: a = 3.1764 Å, c = 5.1939 Å)-with errors under 1.5%. These findings confirm the precision and robustness of the proposed calculation technique. Overall, this study presents a cost-effective route for synthesizing ZnO nanostructures with tunable properties, promising broad applicability in electronic, photonic, and catalytic technologies.