Eu 3+ -based luminescence ratiometric thermometry.

Recently, luminescence ratiometric thermometry has gained ever-increasing attention due to its merits of rapid response, non-invasiveness, high spatial resolution, and so forth. For research fields relying on temperature measurements, achieving a higher relative sensitivity of this measurement is still an important task. In this work, we developed a strategy for achieving a more sensitive temperature measurement, one merely depending on the photoluminescence of Eu 3+ . We showed that using the 5 D 1 - 7 F 1 transition and the hypersensitive 5 D 0 - 7 F 2 transition of Eu 3+ can boost the relative sensitivity compared with the method relying on the 5 D 1 - 7 F 1 and 5 D 0 - 7 F 1 transitions of Eu 3+ . The difference between these two strategies was studied and was explained by the hypersensitive 5 D 0 - 7 F 2 transition more steeply decreasing than the 5 D 0 - 7 F 1 transition with a rise in temperature. Our work is expected to help researchers design sensitive optical thermometers via proper use of this hypersensitive transition.