Temperature sensing performance of dysprosium doped aluminum oxide powders

Dy³⁺-doped Al₂O₃ powders were prepared by combustion synthesis. Down-converted luminescence lines peaked at 451 and 471, 572, 660, 708 and 752 nm were obtained under 355 nm pulsed laser irradiation for as-prepared Dy³⁺ doping concentrations of 0.5, 1.0 and 2.0 wt.%. The fact that the relative intensities of the 451 and 471 nm luminescence bands changed with the samples temperature allowed the use of these emission lines for temperature sensing. We found that the maximum sensitivity of the temperature sensor based on the luminescence intensity ratio of those transitions changed with Dy³⁺ doping concentration indicating different coupling strengths between the crystal field and the rare-earth.