Abstract:

Dy³⁺, Eu³⁺, and Dy³⁺-Eu³⁺ doped Ba₂CaWO₆ phosphors are synthesized by solid-state method. The structural and morphological studies of the Ba₂CaWO₆ phosphors are conducted by measuring X-ray diffraction pattern and scanning electron microscope images. The photoluminescence (PL) spectra of the Ba₂CaWO_6：Eu³⁺ phosphor exhibit the intense red emission due to the transition of ⁵D₀-⁷F₁/⁷F₂ while the Ba₂CaWO_6：Dy³⁺ phosphor shows the blue (⁴F_9/2-⁶H_15/2) and yellow (⁴F_9/2-⁶H_13/2) emissions. The Eu³⁺/Dy³⁺ ions co-doped Ba₂CaWO₆ phosphor shows the improved white light by shifting towards the warm white region. The energy transfer from Dy³⁺ to Eu³⁺ ions is investigated by means of PL intensities. The luminescence intensities and chromaticity coordinates can be modified by controlling the concentration and the ration of doping Dy³⁺ and Eu³⁺. The calculated chromaticity coordinates indicate that Ba₂CaWO_6：Eu³⁺/Dy³⁺ phosphors may be suitable for the fabrication of near-UV excitation-based white light-emitting diodes.

Key words: luminescence; energy transfer; Dy³⁺-Eu³⁺ ; Ba₂CaWO₆