Research on upconversion and temperature sensing properties of Er3+/Yb3+ codoped glass ceramics containing BaF2 crystals

Abstract

Er³⁺/Yb³⁺ codoped glass ceramics containing BaF₂ crystals were obtained through a melt quenching process; the precipitation of BaF₂ nanocrystals was confirmed by structural characterization. The effects of crystal quantity and size on the transmittance and upconversion fluorescence of the samples were analyzed. The precipitation of nanocrystals leads to a significant increase in upconversion luminescence intensity. The fluorescence spectra at different pump powers were measured. Er³⁺ and Yb³⁺ energy level diagrams and possible energy transfer routes during upconversion luminescence were explored. Furthermore, the functional relationship between temperature and the upconversion fluorescence intensity ratio of the samples was analyzed. When the temperature is 293 K, the relative sensitivity reaches the maximum of 1.38% K⁻¹.