Abstract
Un-doped and 1.5% Pb2+doped zinc aluminate (ZnAl2O4) was successfully prepared at a relatively low temperature (~80°C) using the sol–gel process. The Zn/citric acid (CA) mole fraction was varied from 0.083 to 1.3. The X-ray diffraction (XRD) data revealed that most of the annealed samples consist of the cubic ZnAl2O4 structure with ZnO impurities. The surface morphology of the phosphors was influenced by the Zn/CA mole fractions. The increase in the CA content lead to the morphological evolution and transformation from small particles to rods-like-needles. The nanopowder samples exhibited violet luminescence that varied from 400 to 410nm, which suggested that the CA content affected the bandgap energy of the host. The results suggest that the emission originated either from the host, Pb2+ or ZnO impurities. Emission at 400nm is attributed to the oxygen vacancies (V0*) in the host and emission peak at 410nm is attributed to the intrinsic defects emission of ZnO, while the emission at 552nm is attributed to the second order emission of the excitation wavelength. The emission intensity was influenced by the Zn/CA mole fractions. The CIE colour coordinates of all samples are close to each other in the blue region. Two distinct peaks were observed at around 160 and 385°C in thermo luminescence (TL) glow curve, which indicates that there are two set of traps.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
