High sensitivity temperature sensing material In2Li3P3O12: Bi3+, Eu3+ based on effective energy transfer from Bi3+ to Eu3+

In recent years, fluorescent temperature sensing materials have been widely studied because they can realize remote non-destructive temperature measurement. High temperature sensitivity and excellent temperature resolution are the eternal pursuit of fluorescence temperature sensing. Here, we report the preparation, structure, luminescent properties and temperature sensing performance of phosphor In₂Li₃P₃O₁₂: Bi³⁺, Eu³⁺. Eu³⁺ singly doped samples can emit red light under 270 nm excitation. There is effective energy transfer from Bi³⁺ to Eu³⁺ in the Bi³⁺ and Eu³⁺ co-doped samples. Doping Bi³⁺ on the basis of doping Eu³⁺ can significantly enhance the luminescence intensity of Eu³⁺ ions. Ultraviolet light from Bi³⁺ and red light from Eu³⁺ are chosen to design a fluorescence intensity ratio thermometer for more accurate temperature detection. The temperature sensing technology has a maximum absolute and relative sensitivity is up to 0.0087 K⁻¹ at 298 K⁻¹ and 2.71 % K⁻¹ at 325 K, respectively. This has a higher sensitivity than many phosphors available on the market. This indicates that it is a kind of fluorescence temperature sensing material with great potential.