Up-conversion luminescence and energy transfer mechanism in ZnTiO₃: Er³⁺,Yb³⁺ phosphor

Er³⁺ and Yb³⁺ doped zinc titanate (ZnTiO₃) was successfully synthesized using the conventional solid-state reaction method. X-ray diffraction confirmed crystallization of an ecandrewsite ZnTiO₃ of an undoped sample, although impurity phases from the dopants were present in the doped and co-doped samples. The surface analysis showed a morphology composed of agglomerated irregular shaped particles. The energy band gap of ZnTiO₃ was affected by the incorporation of different concentrations of rare-earth dopant ions. After irradiating the ZnTiO₃:Er³⁺,Yb³⁺ phosphors with a 980 nm laser beam, the phosphor displayed up-converted photoluminescence emission in the visible range of the electromagnetic spectrum. The emission mostly consisted of green and red bands of Er³⁺ ions with peaks located at 527, 545 and 665 nm. Co-doping with Yb³⁺ ions proved effective in enhancing the luminescence intensity of the Er³⁺ ion emission, through an energy transfer mechanism.