Enhancement upconversion luminescence of In2O3: Er3+, Yb3+ phosphors by Al3+ ions doping

Abstract

The In₂O₃: 4 % Er³⁺, 10 % Yb³⁺, x % Al³⁺ (x = 0, 1, 2, 5) phosphor were prepared by high temperature solid phase method. At 980 nm laser excitation, the emission peaks near 552 nm and 661 nm correspond to the ⁴S_3/2 → ⁴I_15/2 and ⁴F_9/2 → ⁴I_15/2 transitions of the Er³⁺ ion. With the doping of Al³⁺ ions, the luminescence intensity of the phosphor increased significantly. In addition, the upconversion luminescence intensity is the highest when 2 % Al³⁺ ions are doped. The mechanism of upconversion luminescence was investigated by power dependence, UV–Vis–NIR absorption spectrum, photoluminescence excitation spectrum and down-conversion luminescence spectrum. In addition, the temperature sensing of phosphor in the temperature range of 298 K–598 K was studied by fluorescence intensity ratio technique. The phosphors showed maximum absolute and relative sensitivity of 0.067 K^-1 and 1.13 % K⁻¹, respectively.