The Institute

Title: Modulating Thermometric Performance via Dopant Concentration and Morphology in a Luminescence Thermometer Exhibiting Dual Structural Phase Transitions

Authors: M. Kubicka, M. Szymczak, M. Ptak, D. Szymanski, V. Kinzhybalo, M. Drozd, L. Marciniak

Journal: Chemistry of Materials

DOI: 10.1021/acs.chemmater.5c00881   

Extending the thermal operating range of luminescent thermometers based on thermally induced first order phase transitions in lanthanide-doped materials requires the investigation of new host matrices with diverse thermal properties.

In line with this objective, Prof. Marciniak's group investigated the spectroscopic properties of Li₃Sc₂(PO₄)₃:Eu³⁺ over a wide temperature range in their latest work. The results of the study indicate that the material undergoes two reversible phase transitions: a γ_LT → α/β phase transition at a temperature of approximately 160 K, followed by a β → γ_HT transition at a temperature of approximately 550 K. These transitions induce significant changes in the emission spectra and luminescence decay kinetics of Eu³⁺ ions. By using the appropriate thermometric parameter LIR, a relative sensitivity of 7.8% K^-1 at 160 K for 0.1% Eu³⁺ and 0.65% K^-1 at 550 K for 0.5% Eu³⁺ was obtained. In addition, the study showed that the phase transition temperature in Li₃Sc₂(PO₄)₃:Eu³⁺ can be modulated by changing the concentration of dopant ions and the annealing conditions of the phosphor, which in turn affects the morphology of the material. These strategies enable precise tuning of the thermometric parameters of phase transition-based luminescent thermometers.

This work was funded by the NCN OPUS project UMO- 2022/45/B/ST5/01629.