Photoluminescence of Dy³⁺ activator sensitized by Ce³⁺ in KNaSO₄ microphosphor

Abstract

The KNaSO4 microphosphor doped with Ce or Ce and Dy prepared by a wet chemical method was studied by scanning electron microscopy (SEM) and characterized by photoluminescence (PL). KNaSO4 has a 5-µm particle size detected by SEM. The KNaSO4:Ce(3+) spectrum shows a single emission band at 327 nm for an excitation of 269 nm due to 5d → 4f transition of the Ce(3+) ion, indicating weak spin orbiting coupling of the Ce(3+) ground state. Efficient energy transfer takes place from Ce(3+) → Dy(3+) sublattices indicating that Ce(3+) could effectively sensitize Dy(3+) (orange emission) and that the Ce(3+) emission weakens significantly in KNaSO4. The powder form of prepared KNaSO4 show negligible change in morphologies and hence no effect on the particle size. The characteristics of this powder could provide improved luminescence properties. The development and understanding of this photoluminescence and the effect of Dy(3+) on KNaSO4:Ce(3+) are discussed.