Inherently Eu<sup>2+</sup> /Eu<sup>3+</sup> Codoped Sc<sub>2</sub> O<sub>3</sub> Nanoparticles as High-Performance Nanothermometers.

Pan, Yue; Xie, Xiaoji; Huang, Qianwen; Gao, Chao; Wang, Yangbo; Wang, Lingxiao; Yang, Bingxiao; Su, Haiquan et al. · Adv Mater · 2018

basic_science · Level V

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Abstract

Luminescent nanothermometers have shown competitive superiority for contactless and noninvasive temperature probing especially at the nanoscale. Herein, we report the inherently Eu<sup>2+</sup> /Eu<sup>3+</sup> codoped Sc<sub>2</sub> O<sub>3</sub> nanoparticles synthesized via a one-step and controllable thermolysis reaction where Eu<sup>3+</sup> is in-situ reduced to Eu<sup>2+</sup> by oleylamine. The stable luminescence emission of Eu<sup>3+</sup> as internal standard and the sensitive response of Eu<sup>2+</sup> emission to temperature as probe comprise a perfect ratiometric nanothermometer with wide-range temperature probing (77-267 K), high repeatability (>99.94%), and high relative sensitivity (3.06% K<sup>-1</sup> at 267 K). The in situ reduction of Eu<sup>3+</sup> to Eu<sup>2+</sup> ensures both uniform distribution in the crystal lattice and simultaneous response upon light excitation of Eu<sup>2+</sup> /Eu<sup>3+</sup> . To widen this concept, Tb<sup>3+</sup> is codoped as additional internal reference for tunable temperature probing range.