Up-conversion emission of Yb3+/Tm3+-activated SrNb2O6 lead-free glass-ceramics for optical temperature sensors

The development of fluorescent materials with excellent thermal stability and high-temperature sensitivity is urgently needed to meet the rapidly growing temperature sensors. In this paper, the SrO-SrF2-Nb2O5-Al2O3-B2O3-SiO2-Yb2O3-Tm2O3 glasses were fabricated by high-temperature melting method. And the glass-ceramic with the optimal concentration of 4.0Yb(3+)/0.1Tm(3+) was obtained after heat treatment of 800 degrees C for 30 min. Only the nanocrystalline SrNb2O6 crystal phase with a tetragonal structure precipitated from the glass matrix. The as-prepared glass-ceramic material produced intense blue light emission and excellent thermal cyclic stability. Utilizing the fluorescence intensity ratio technique, the glass-ceramic material showed the supreme relative sensitivity of 2.63 %K-1 at 298 K using thermally coupled energy levels (TCELs) and the highest absolute sensitivity of 22.10 %K-1 at 598 K employing non-TCELs. These findings show that Yb3+/Tm3+- doped SrNb2O6 glass-ceramic material is a promising candidate for optical sensor application.