Undoped and Sm3+ doped ZnAl2O4 nanopowders were synthesized using the co-precipitation method and annealed at 750 ℃ for 3.5 h. The aim of this study was to investigate the effect of varying the Sm3+ concentration on the ZnAl2O4 structure, morphology, and optical properties. The X-ray diffraction analysis confirmed that the samples have a face-centred cubic structure. Crystallite size decreased with an increase in Sm3+ concentration. Scanning electron microscopy revealed that the addition of Sm3+ slightly influence the morphology of the samples. Transmission electron microscopy confirmed a slight decrease in particle sizes. Energy-dispersive X-ray spectroscopy analysis confirmed the anticipated elemental composition. Ultraviolet–visible spectroscopy showed an increase in bandgap compared to the host. Photoluminescence analysis indicated that doping with Sm3+ induced defects within ZnAl2O4. The emission peaks observed around 380, 401, 451, 500, and 739 nm are attributed to host material. The emission peaks at 564, 601, and 649 nm correspond to the 5G5/2 → 6H5/2, 6H7/2, and 6H9/2 transition of Sm3+, respectively. The highest luminescence intensity was found for the 0.5 % Sm3+ sample. The CIE colour chromaticity diagram showed that the emission colour could be tuned from bluish to nearly white to orange.
- Surface defects