Construction of Novel Luminescent Thermometers Based on Dual-Emission Centers of Rare-Earth and Bismuth Ions

Optical thermometry based on fluorescence intensity ratio (FIR) technology has several advantages such as remote signaling, non-invasiveness, and excellent spatial resolution. These qualities are needed in industrial and medical applications. Here, we prepared luminescent thermometers by doping of rare earth (RE) elements (e.g., samarium (Sm 3+ ) or europium (Eu 3+ )) into Ca 2 Y 0.97 Bi 0.03 SbO 6 (CYBS) phosphors via high-temperature solid-state reactions. Tuning of the CYBS:Eu 3+ and CYBS:Sm 3+ ratios in the phosphors provided a wide range of color changes from purplish blue to red and from purplish blue to pink, respectively. The higher values of absolute sensitivity (S a ) and relative sensitivity (S r ) resulted in better optical thermometry performance. Both phosphors exhibit excellent temperature sensing with S a /S r values (at 483 K) of 4.945×10 -2 /0.968×10 -2 K -1 (CYBS:0.05Eu 3+ ) and 2.964×10 -2 /0.864×10 -2 K -1 (CYBS:0.05Sm 3+ ). Thus, RE doped CYBS materials with color tuning properties and superior temperature sensing performance are recommended for the construction of novel luminescent optical thermometers