Enhanced up-conversion luminescence and temperature sensing performance of NaBiF4: Er3+, Yb3+, Al3+

Rare earth doped fluoride-based up-conversion luminescent materials have been widely studied in non-contact temperature sensing technology. However, the luminous intensity of the fluoride at high temperature still needs to be improved. Here, enhanced up-conversion luminescence and temperature sensing performance of NaBiF4: Er3+, Yb3+ is realized by Al3+ substitution. The samples exhibit the characteristic green (521 nm and 540 nm) and red (654 nm) emissions of Er3+ ion under 980 nm excitation. When the concentration of Al3+ is 5%, the green emission is enhanced by about 10 times, and the red light is enhanced by about 7 times. Obvious lattice shrinkage caused by the introduction of Al3+ is responsible for the enhancement. In addition, the optimal sample is highly thermally stable from 303 K to 443 K. The maximum relative sensitivity at 303 K increases from 0.791% K-1 to 1.106% K-1. The results indicate that NaBiF4: Er3+, Yb3+, Al3+ be a potential thermosensitive material.