Enhanced non-contact optical temperature sensing performance based on upconversion luminescence in Ho3+/Yb3+ codoped ferroelectric 0.94Na0.5Bi0.5TiO3-0.06BaTiO3

Abstract

The upconversion luminescence of ferroelectric 0.94Na0.5Bi0.5TiO3-0.06BaTiO3: xHo3+/0.01Yb3+ is investigated in detail. The prepared samples show intense characteristic emission from Ho3+ ions with a dominant green emission peak located at 547 nm under 980 nm excitation. Among these solid solutions, the 0.94Na0.5Bi0.5TiO3-0.06BaTiO3: 0.0075Ho3+/0.01Yb3+ ceramic possesses the optimum emission. Optical temperature sensing behavior of Ho3+/Yb3+ codoped ferroelectric 0.94Na0.5Bi0.5TiO3-0.06BaTiO3 are investigated through fluorescence intensity ratio (FIR, I656/I547) induced by non-thermally coupled energy levels 5F5→5I8 and 5F4/5S2→5I8 in the range of 303–483 K. A moderate amount of Yb3+ doping in 0.94Na0.5Bi0.5TiO3-0.06BaTiO3: Ho3 + ceramic contributes to the improvement of their optical temperature sensing performance. At T = 303 K, the calculated highest relative sensitivity SR is 0.0042 K-1, which indicates that the optimized 0.94Na0.5Bi0.5TiO3-0.06BaTiO3: 0.0075Ho3+/0.01Yb3+ ceramic is promising as the candidate materials for noncontact optical temperature sensing devices.