Effect of zinc precursor ratio on morphology and luminescent properties of ZnO nanoparticles synthesized in CTAB medium

In this study, the effect of zinc precursor ratio on structural, morphology and luminescent properties of zinc oxide (ZnO) nanoparticles (NPs) prepared by cationic surfactant-assisted method was studied. ZnO NPs were prepared at room temperature by increasing Zn2+: CTAB mole ratio. The pristine ZnO samples showed phase-purity (without need for calcination) as shown by X-ray diffractograms (XRD). Nitrogen adsorption - desorption analysis showed that the samples exhibit Type III isotherm and H3 hysteresis with mesoporosity. The triangular to quadrilateral-shaped morphological evolution of the ZnO NPs with increasing concentrations of zinc ions was confirmed by SEM and TEM images of the samples. The UV-Vis-DRS studies showed blue-shifted lambda(max) (band gap) in all the ZnO samples which indicated their nanostructured nature. The photoluminescence spectra of these ZnO samples show emissions in UV and visible regions. The mechanism of formation of nanostructured ZnO was suggested based on the model reported for mesoporous silica synthesized in CTAB medium.