The effect of Ce3+ on structure, morphology and optical properties of flower-like ZnO synthesized using the chemical bath method

Abstract

Ce3+ doped ZnO flower-like structures were synthesized by the chemical bath deposition method (CBD). The influence of Ce3+ as a dopant on the crystallization, surface morphology, optical and luminescent properties of ZnO flowers-like structures were investigated. The X-ray diffraction (XRD) spectra of the ZnO:Ce3+nanostructures correspond to the various planes of a single hexagonal ZnO phase for the lower Ce concentration samples. The estimated grain sizes calculated using the XRD spectra were found to be in order of 42±2nm. The grain size was found to be not dependent on the concentration of the Ce3+ ions used up to 3mol% of Ce. Scanning Auger electron microscopy and scanning electron micrographs indicate that the addition of Ce3+ influence the morphology of the samples. The flower-like structures obtained for the undoped and low concentration Ce doped ZnO changed into a mixed structure with the emergence of pyramid shapes for higher concentration Ce doped samples. The solid undoped and low concentration Ce doped powder showed good optical properties with a high reflectance in the visible regions. The properties, however, diminished at higher Ce concentration. The band gap energies decreased linearly with concentration from 3.0±0.1 to 2.4±0.3eV for ZnO:0mol% Ce3+ up to ZnO:10mol% Ce3+. Under 248nm excitation, the undoped and low concentration Ce doped ZnO flower-like rods exhibited a green emission, peaking at about 559nm. The higher Ce concentration (0.3mol% and above) was emitted at 436 and 503nm due to the Ce transitions. The intensity of these emission spectra of the ZnO:Ce3+ decreased with the addition of more Ce3+ ions.