YVO<sub>4</sub> Nanoparticles Doped with Eu<sup>3+</sup> and Nd<sup>3+</sup> for Optical Nanothermometry
Ilya E. Kolesnikov, Daria V. Mamonova, Mikhail A. Kurochkin, Evgenii Yu. Kolesnikov, E. Lähderanta, Alina Manshina
Abstract
The ongoing research in biology, medicine, and technology requires accurate measurement and control of temperature at micro and nanoscales. Rare-earth-doped luminescence nanoparticles were found to be one of the most perspective systems for noncontact ratiometric temperature sensing for various applications. Despite plenty of single-doped sensors with thermally coupled levels, the development of a dual-center thermometer with enhanced thermometric performances is still challenging. Here, we demonstrate two approaches to construct ratiometric luminescence YVO4:Eu3+/Nd3+ nanothermometers: co-doping and mixture of single-doped nanoparticles. The rational choice of doping concentration could significantly improve thermometric characteristics. An increase in doping concentration did not affect thermal sensitivity, while temperature resolution was improved. Co-doped and mixed nanoparticles displayed similar thermal sensitivity (∼0.8% K–1), whereas the temperature resolution of mixed sensors (0.4–1.0 K) was found to be several times better compared to the co-doped ones (1.1–3.0 K). The obtained results provide a strategy for developing promising dual-center luminescence thermometers with submicron spatial and subdegree thermal resolution.