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 photo-luminescence 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.