Comparative analysis of upconversion emission of LaF3:Er/Yb and LaOF:Er/Yb for temperature sensing

Up-conversion (UC) luminescence of Er3+ greatly depends on the host matrix. In the present study, the comparison of UC emission from Er3+ is investigated by varying host matrix, including hexagonal LaF3, rhombohedral (R-) and tetragonal (T-) LaOF. The tetragonal LaOF:Er/Yb exhibits the most intensive emission under the same condition. Instead of phonon threshold and phase structure, local field symmetry after doping is the main reason for its luminescence enhancement. T-LaOF:Er/Yb is selected as the candidate for temperature sensing. The pump power dependent UC emission and optical temperature sensing properties of T-LaOF:Yb/Er are investigated. The results suggest that T-LaOF:Er/Yb not only exhibit more intense emission, but also has higher sensitivity. Its maximum sensitivity is 3.5 parts per thousand K-1 around 400 K, suggesting it is a potential candidate in temperature sensing. (C) 2019 Elsevier B.V. All rights reserved.