Mn 4+ -doped rare-earth-free Mg 4 Nb 2 O 9 phosphors for optical temperature sensing.

In this report, rare-earth-free Mg 4 Nb 2 O 9 :Mn 4+ phosphors were obtained through a high-temperature solid-state reaction. This work aims to investigate the photoluminescence properties of Mg 4 Nb 2 O 9 :Mn 4+ phosphors and the temperature sensitive performance of the optimized phosphor. The crystal structure and lattice parameters as well as the effects of the dopant ions on the host structure were investigated. It should be noted that the Mg 4 Nb 2 O 9 crystal is in a trigonal system P 3̄ c 1. The as-prepared phosphors exhibited good thermal sensitivity, and the relative sensitivity of the optimal Mg 4 Nb 2 O 9 :0.004Mn 4+ phosphor was calculated to be 0.48% K -1 , allowing it to activate optical temperature sensing applications.