Self-calibrated optical thermometer based on luminescence from SrLu2O4:Bi3+,Eu3+ phosphors

Abstract

Bi³⁺,Eu³⁺ co-doped SrLu₂O₄ phosphors were synthesized by a solid state reaction method. Their structural, luminescent and temperature sensing properties have been systematically investigated. The color-tunable emissions from violet to red were detected with the increase of Eu³⁺ concentration. Relying on energy transfer process from Bi³⁺ to Eu³⁺ and thermal quenching behaviour, the fluorescence intensity ratio (FIR) presents excellent temperature sensing performance. The maximum absolute and relative sensitivities reach 1.10% K⁻¹ and 0.87% K⁻¹, respectively. These meaningful results indicate that SrLu₂O₄:Bi³⁺,Eu³⁺ is a promising material for optical temperature sensing.