Novel highly efficient single-component multi-peak emitting aluminosilicate phosphors co-activated with Ce3+, Tb3+ and Eu2+: luminescence properties, tunable color, and thermal properties.

ABSTRACT

A series of emission-tunable Ce3+/Tb3+/Eu2+ doped Ca2(Mg0.75Al0.25)(Si1.75Al0.25)O7 (denoted as CMAS) phosphors have been synthesized via a high temperature solid-state reaction method. The luminescence properties, color tuning, quantum yields (QYs), energy transfer of Ce3+ to Tb3+/Eu2+, thermal stability, performance of LED devices and ratiometric temperature sensing application have been systematically investigated, respectively. Importantly, through the study of thermal stability, we found that Ce3+ and Tb3+ co-doped samples were suitable for WLED applications, while Ce3+ and Eu2+ co-doped samples were suitable for temperature sensing applications. Due to the energy transfer, Ce3+/Tb3+ co-doped samples had high luminous efficiency and the quantum efficiency of more than 80% could be achieved. Their emission colors can modulate from blue to green. In addition, on the basis of the evaluation of the as-fabricated white LED lamps via selecting the corresponding phosphors, the CCT can reach 4275 K and the CRI can increase to 86.8, indicating that this series of phosphors can act as potential color-tunable phosphors for possible applications in ultraviolet light based white LEDs. Importantly, it is found that the fluorescence intensity ratio of CMAS 5%Ce3+,0.5%Eu2+ displays linear correlation with temperature in a wide range of 253-373 K with a high sensitivity of 2.49% K-1, indicating that it could be a good candidate for ratiometric optical thermometry.