Fixed Yellow-to-Blue Intensity Ratio of Dy3+ in KY(CO3)2 Host for Emission Color Tuning

Abstract

Dy3+, Ce3+ co-doped KY(CO3)2 phosphors with a monoclinic structure were synthesized using the hydrothermal method to create a fixed yellow-to-blue ratio emission. The [YO8] polyhedron, consisting of a Y atom and eight oxygen atoms, forms a relatively independent microstructure within the KY(CO3)2 host. Y3+ ions are partially replaced by Ce3+ or Dy3+ ions to construct the [CeO8] or [DyO8] polyhedral fluorescence emission unit. The spectral measurements indicate that Ce3+ and Dy3+ can maintain relatively independent fluorescence emission characteristics in the KY(CO3)2 host. The yellow-to-blue intensity ratio of Dy3+ remains close to 1 and does not change with the variation in the doping concentration of KY(CO3)2:Dy3+ and KY(CO3)2:Dy3+,Ce3+ phosphors. When Ce3+ and Dy3+ are co-doped with KY(CO3)2, the emission intensities of Dy3+ under 339 nm and 365 nm excitation increase by 8.43 and 2.32 times, respectively, through resonance energy transfer and cross-relaxation. All Ce3+-doped KY(CO3)2:Dy3+ phosphors can emit white light. Among them, the emitted light of KY(CO3)2:3%Dy3+,5%Ce3+ is closest to standard daylight. Therefore, a stable [YO8] polyhedral structure can be used to achieve more color tuning of light.