Fangfang Hu

Transparent Na5Gd9F32:Er3+ glass-ceramics: enhanced up-conversion luminescence and applications in optical temperature sensors

New rare earth ion-doped nanocomposite materials, Na5Gd9F32:Er3+ glass-ceramics, were fabricated via a traditional melt-quenching technique and subsequent heat treatments. Their microstructural and optical properties were systemically investigated by XRD, TEM, HRTEM techniques, absorption, up-conversion spectra and luminescence lifetime measurements. Excited by 980 nm laser, both glass and glass-ceramic samples presented characteristic red and green up-conversion emissions of Er3+ ions. After crystallization, Er3+ ions were incorporated into the precipitated Na5Gd9F32 nanocrystals. Compared with precursor glasses, the red up-conversion intensity of glass-ceramics was enhanced by 1300 times, and the luminescence lifetime was also prolonged. The fluorescence intensity ratio technique was utilized to carry out the optical thermometry based on the green up-conversion luminescence behavior of Er3+ ions. Results manifest that Na5Gd9F32:Er3+ glass-ceramics would have potential applications in optical temperature sensors with high sensitivity.

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.