Achieved High-Sensitivity Single-Band Ratiometric Optical Thermometry by Manipulating the Intervalence...

Currently, optical thermometry has received widespread attention because of its noncontact and wide temperature range, but most of them are based on the application of dual-band optical ratiometric thermometry, so the development of a single-band ratiometric (SBR) optical thermometry, which is easier to analyze and use, is particularly important. In this work, the position of the intervalence charge-transfer (IVCT) band for Na₂Gd_2-LaTi₃O₁₀:Pr³⁺ (x = 0, 0.5, 1.0, 1.5, 2.0) was modulated using Gd/La substitution, enhancing the thermal response difference of Pr^{3+ 1}D₂ → ³H₄ under charge-transfer band (CTB) and IVCT band excitation, thereby achieving high-sensitivity SBR optical thermometry, and the maximum relative sensitivity (S_r-max) reached 2.95% (at 298 K). In addition, this series of phosphors has high-color-purity red emission, indicating that it has potential for multifield applications.