Luminescence thermometry with Eu³⁺ doped GdAlO₃

Eu³⁺ doped GdAlO₃ powder synthesized by solid state reaction was investigated for application in luminescence thermometry. Phase composition of material was confirmed by X-ray powder diffraction analysis. The photoluminescence emission spectra were collected under excitation of 399 nm, while elevating the temperature of the sample from the room temperature to 793 K. Emissions from ⁵D₁→⁷F₁ and ⁵D₀→⁷F₂ characteristic transitions of Eu³⁺ ions are selected for the temperature-dependence study using the fluorescence intensity ratio method. Emission decay curves measured at the strongest emission peak centered at 614 nm were recorded in a same temperature range. Data analysis showed that thermometry by fluorescence intensity ratio method can be used over the temperature region 293–793 K with the maximal relative sensitivity of 2.96% K⁻¹ (at 293 K). Temporal dependence of emission (lifetime) provides temperature sensing from 620 to 793 K with the maximal relative sensitivity of 2.28% K⁻¹. - Highlights: • GdAlO₃: 4 at% of Eu³⁺ can be used for luminescence thermometry in the 293–793 K range. • Combined FIR and lifetime thermometry provide >0.5% K⁻¹ relative sensitivity. • Temperature dependence of lifetime is well described energy gap law model.