Intense up-conversion emission from Er3+/Yb3+ ion co-doped transparent oxyfluoride glass-ceramics containing Y5O4F7 nanorods for optical thermometry

Abstract

Er³⁺/Yb³⁺ ion co-doped transparent glass-ceramics containing Y₅O₄F₇ nanorods were prepared through a conventional melt-quenching method and a subsequent heat-treatment method. The XRD patterns, transmission spectra, HR-TEM images and elemental distribution mapping results showed that Er³⁺ and Yb³⁺ ion incorporated NaYF₄ nanospheres and Y₅O₄F₇ nanorods were formed in glass-ceramics when heat-treatment was carried out at temperatures 620 °C and 650 °C, respectively. As a consequence, continuous greatly enhanced up-conversion emission from Er³⁺ ions was obtained. The changes of the absorption spectra and decay curves revealed that the relatively high concentration and multiple doping sites in low symmetry orthorhombic Y₅O₄F₇ nanorods should account for the intense up-conversion emission. Furthermore, a relatively large ΔE (818 cm⁻¹) and a high S_R (1.31% K⁻¹ at 300 K) were obtained when evaluating the potential application of this novel glass-ceramic in temperature sensing. These results show that transparent glass-ceramics containing Y₅O₄F₇ nanorods are promising candidates as up-conversion host materials for a variety of applications.