Energy Gap Linear Superposition of Thermally Coupled Levels toward Enhanced Relative Sensitivity of Ratiometric Thermometry

作者：Wang, Yuzhen; Sun, Yongsheng; Xia, Zhiguo^*

来源：Journal of Physical Chemistry Letters, 2022, 178-182.

DOI：10.1021/acs.jpclett.2c03587

• LUMINESCENCE

Ratiometric luminescence thermometry (RLT) has attracted considerable attention for its non-invasive, fast response, and strong electromagnetic interference resistance; however, improving relative sensitivity (SR) is of great significance. Herein, we propose a design principle to promote SR by linearly superposing the energy gaps of thermally coupled levels (TCLs) subordinated to luminescence centers. A new fluorescence intensity ratio (FIR ') is derived from multiplying the previous FIRs of multi-pair TCLs. Then, a new SR ' is significantly enhanced and proves to be the sum of the original SR values. The feasibility of this approach is proclaimed by applying to several materials [Na0.5La0.5TiO3:Yb/Nd, Y2O3:Yb/Er, and (LiMg)2Mo3O12:Yb/Er] with improved SR for RLT. Finally, a flexible film is fabricated for temperature measurement of actual scenes and manifests the superiority of the energy gap linear superposition method as ratiometric thermometry.