Luminescence and energy transfer of color-tunable LiNbO3:Tm3+/Dy3+/Eu3+ phosphor with high thermostability for WLED

A series of Tm 3+ /Dy 3+ /Eu 3+ single and co-doped LiNbO 3 color tunable phosphors were synthesized via the solid-state reaction. The phase structure, microscopic topography, optical characteristics, decay lifetimes, energy transfer processes，and thermal stability were comprehensively characterized through combined X-ray diffraction analysis, scanning electron microscope, and advanced spectroscopic methodologies. Following further in-depth analysis, the optimal concentration of dopant ions was determined, and the energy transfer effect between activators in the LiNbO 3 matrix was confirmed. The CIE demonstrated that adjusting the doping concentration of rare earth ions makes it possible to achieve polychromatic tunable light, as well as cool and warm white light. Crucially, Li 0.95 NbO 3 :0.01Tm 3+ /0.02Dy 3+ /0.02Eu 3+ phosphor exhibited remarkable thermal stability, maintaining 97.1 % of its initial strength at temperatures of 423 K. Additionally, WLEDs that have been coated with the aforementioned phosphor on a 365 nm NUV chip emit bright white light, exhibiting a color rendering index of 81.3 and correlated color temperature of 5426 K. It is powerfully suggested that the LiNbO 3 :Tm 3+ /Dy 3+ /Eu 3+ phosphors has the potential to become a new choice for WLED application.