Upconversion luminescence and temperature sensing properties of Ba₃GdAl₂O7.5: Yb³⁺, Er³⁺ phosphor

In recent years, lanthanide-doped upconversion materials have received abundant attentions due to their long fluorescence lifetime, narrow emission bandwidths, and large anti-Stocks shift. However, weak brightness generally exists in upconversion materials and it becomes one of the major bottlenecks in the practical applications. Therefore, developing more materials with excellent upconversion luminescence properties is urgent. Herein, a green phosphor Ba 3 GdAl 2 O 7.5 : Yb 3+ , Er 3+ is obtained by high-temperature solid-state method. The crystal structure is characterized by the X-ray powder diffraction. The upconversion luminescence properties are displayed under the excitation of 980 nm near-infrared laser, and the optimal doping concentrations of Yb 3+ and Er 3+ ions in the crystal are determined by the control variable method. In addition, the excellent temperature sensing performance of Ba 3 GdAl 2 O 7.5 : 0.2Yb 3+ , 0.02Er 3+ indicates that it is a candidate for practical applications as an optical temperature sensor.