An Ionic Liquid-Based Optical Thermometer

We report on a high performance ratiometric luminescent thermometer based on the reversible temperature-dependent excited-state self-association of the probe 1,3-bis(1-pyrenyl)propane dissolved at a few parts per million in the ionic liquid [C4mpy][Tf2N]. The thermometer performs well over the 25-140 °C range, is rapid and completely reversible, and exhibits an average imprecision of less than ± 0.20 °C over the truncated temperature range 25 °C≤T≤ 120 °C. The precision near physiological temperature is slightly better (± 0.12 °C) suggesting possible applications on the operating table and in the battlefield.