Color-tunable luminescence based on the efficient energy transfer of a Tm-Dy system for optical thermometry and white LED lighting

The development of phosphors with color-tunable luminescence including white emission is at the forefront of lighting and display technologies. Herein, Dy3+,Tm3+ single-doped or co-doped K3Y(PO4)2 phosphors are synthesized through the solid-state reaction method. By properly adjusting the ratio of Dy3+,Tm3+ co-doping concentrations, color-tunable luminescence from blue to yellow, including white luminescence, is realized under 359 nm excitation. The mechanism of energy transfer between Tm3+ and Dy3+ is further investigated via measuring the luminescence decay curve. Based on efficient energy transfer from Tm3+ to Dy3+, the emission of Dy3+ exhibits an abnormal thermal enhancement phenomenon as the temperature increases. The optical thermometry behaviors of various emission combinations for the Dy3+,Tm3+ co-doped system are analyzed. The maximum sensitivity can be obtained as a constant of 4.8 x 10-3 K-1, which is conducive to improve the measurement accuracy of optical temperature sensing at high temperatures. Furthermore, we also demonstrate the applicability of K3Y(PO4)2:Tm3+,Dy3+ phosphors in white LEDs, providing proof-of-concept for the lighting and display fields. Dy3+,Tm3+ co-doped K3Y(PO4)2 phosphors with high efficiency energy transfer can achieve color-tunable luminescence and have potential application prospects in the fields of optical temperature measurement and white LED lighting.

Automated summary

In this study, Dy3+,Tm3+ co-doped K3Y(PO4)2 phosphors were synthesized through the solid-state reaction method, achieving color-tunable luminescence and white emission. The mechanism of energy transfer between Tm3+ and Dy3+ was investigated through luminescence decay curve measurements. The phosphors exhibited abnormal thermal enhancement at higher temperatures, making them suitable for optical temperature sensing. Additionally, the potential application of the phosphors in white LEDs was demonstrated.