Koao, L. F.Mofokeng J. P.Motloung, S. V.Moji, Rantooa Goodchild2021-10-272021-10-272020-11http://hdl.handle.net/11660/11330The immobilization of the phosphor particles in a polymer matrix helps to overcome the problem of emitter layer thickness and thus the reproducibility of the emitted light experienced when phosphors are immobilized in glues such as polyurethane or epoxy resin. In this study composites of SiO2:0.4 mol% Sr2+:x mol% Tb3+ (with x = 0.02, 0.06, 0.1, 0.3, 0.4, 0.5) nano-powders dispersed in PLA polymer matrix were successfully prepared through melt mixing. The challenge as shown by the TEM images is that the filler particles tend to agglomerate in the polymer matrix. The XRD results showed broad peaks for all samples, which meant the samples were amorphous. The introduction of the nano-powders into the polymer matrix did not result in the change in the morphology of the samples. The emission peaks that can be associated with the Tb3+ transitions were observed with the dispersion of the nano-powders into the PLA. The SiO2 based phosphors used in this study were prepared using the sol-gel technique and characterized by SEM, TEM, XRD, UV and PL. The SiO2 doped with Sr2+ samples showed an increase in crystallinity with increasing Sr2+ concentration. These singly doped samples showed the highest luminescence at 0.4 mol% Sr2+ concentration, and the CIE analysis showed that the colour coordinates of SiO2:0.4 mol% Sr2+ were related to white light emission. This SiO2:0.4 mol% Sr2+ sample that showed the highest luminescence was co-doped with different mol% Tb3+. The co-doped samples were found to be amorphous with the co-doping and not having any significance on the shape of the particles. The addition of Tb3+ tuned the colour of the phosphors from blue to green.enDissertation (M.Sc. (Chemistry))--University of the Free State (Qwaqwa Campus), 2020PLASiO2TerbiumStrontiumPhotoluminescenceMorphologyCIEDissertationUniversity of the Free State