Rational Design of a Nd3+‐Mn4+ Co‐doped Luminescent Thermometer: Towards High‐Sensitivity Temperature Sensing

Abstract

AbstractHigh temperature sensitivity is an important development direction for luminescent thermometers, especially in the physiological temperature range. Herein, neodymium(III) and manganese(IV) ions were co‐doped into a yttrium gallium garnet host (YGG) and the relevant dopant concentrations were optimized in detail. The temperature‐dependent spectral survey indicates that when the temperature was above 240 K, the 2Eg→4A2g transition of Mn4+ and the 4F5/2→4I9/2 emission of Nd3+ show strong fluorescence quenching and gradual fluorescence enhancement, respectively. Such an apparent contrast mainly originates from the nonradiative cross‐relaxation between 2Eg (or 4T2g) and 4A2g states of Mn4+ and thermal coupling between the 4F5/2 and 4F3/2 levels of Nd3+, respectively. The obvious difference in fluorescence between the two luminescent ions leads to an excellent temperature sensing performance. The obtained relative sensitivity shows a maximum value at 280 K (7.90 % K−1) and maintains a magnitude above 5.00 % K−1 over the whole physiological temperature range. Moreover, the related temperature uncertainties are below 0.1 K from 298 K to 323 K, and the repeatability capability is larger than 98 %. The findings in this study offer a feasible approach to promote the sensing capability of temperature sensors by rationally designing co‐doping systems.