Upconverting NIR-to-NIR LuVO<sub>4</sub>:Nd<sup>3+</sup>/Yb<sup>3+</sup> Nanophosphors for High-Sensitivity Optical Thermometry
Ilya E. Kolesnikov, Е. В. Афанасьева, Mikhail A. Kurochkin, E.I. Vaishlia, Alexey A. Kalinichev, Evgenii Yu. Kolesnikov, E. Lähderanta
Abstract
Accurate contactless thermometry is required in many rapidly developing modern applications such as biomedicine, micro- and nanoelectronics, and integrated optics. Ratiometric luminescence thermal sensing attracts a lot of attention due to its robustness toward systematic errors. Herein, a phonon-assisted upconversion in LuVO4:Nd3+/Yb3+ nanophosphors was successfully applied for temperature measurements within the 323–873 K range via the luminescence intensity ratio technique. Dual-activating samples were obtained by codoping and mixing single-doped nanopowders. The effect of the type of dispersion system and the Yb3+ doping concentration was studied in terms of thermometric performances. The relative thermal sensitivity reached a value of 2.6% K–1, while the best temperature resolution was 0.2 K. The presented findings show the way to enhance the thermometric characteristics of contactless optical sensors.