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

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.