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.