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 for industrial and medical applications such as remote signaling, non-invasiveness, and excellent spatial resolution. Here, an approach to the construction of luminescent thermometers is proposed based on high-temperature solid-state reactions through doping of rare earth (RE) elements (e.g., samarium (Sm3+) or europium (Eu3+)) into Ca2Y0.97Bi0.03SbO6 (CYBS) phosphors. The tuning of the CYBS:Eu3+ and CYBS:Sm3+ ratios in the phosphors provided a wide range of color changes from purplish blue to red and from purplish blue to pink, respectively. The superiority of optical thermometer is validated by higher values of absolute sensitivity (Sa) and relative sensitivity (Sr). As such, both phosphors exhibit excellent temperature sensing performance with Sa/Sr values (at 483 K) of 4.945 × 10-2/0.968 × 10-2 K-1 (CYBS:0.05Eu3+) and 2.964 × 10-2/0.864 × 10-2 K-1 (CYBS:0.05 Sm3+). Thus, RE-doped CYBS materials with color tuning properties and superior temperature sensing performance are recommended for the construction of novel luminescent optical thermometers.