Abstract: High-efficiency yellow-green polychromatic luminescent phosphors Ca₂LaTaO₆∶Dy³⁺, Tb³⁺were obtained by high-temperature solid-state reaction method. The main narrow emission comes from the 547 nm of Tb³⁺ and a wide excitation band is located in the region of 250~400 nm due to the sensitization of Dy³⁺. The energy transfer system was constructed by co-doping Dy³⁺ and Tb³⁺ into Ca₂LaTaO₆ (CLTO) matrix. Furthermore, the energy transfer for Dy³⁺→Tb³⁺ was confirmed by excitation/emission spectra and lifetime decay curve measurements. The energy emigration is dominated by dipole-quadrupole interaction, and the efficiency can reach 80% or even higher. Under the characteristic excitation of Dy³⁺, the luminescence color changes from yellow to green by adjusting the relative doping concentration of Dy³⁺ and Tb³⁺ based on the energy transfer. The results indicate that Ca₂LaTaO₆∶Dy³⁺, Tb³⁺ phosphor with adjustable emission color has potential applications in phosphor-converted white LEDs.

Key words: Ca₂LaTaO₆∶Dy³⁺, Tb³⁺, energy transfer, multicolor luminescence, high temperature solid state, chromaticity coordinate, white LED