Hydrothermal syntheses, luminescent properties, and temperature sensing of monodisperse Tb-doped NaCeF(4) nanocrystals

Monodisperse Tb-doped NaCeF(4) nanocrystals were synthesized via a hydrothermal method. The morphology, and room temperature and temperature dependent luminescent properties were investigated. Excited at 254 nm, the emissions of Ce(3+) at 270–370 nm and those of Tb(3+) at 475–700 nm can be observed. The strongest visible emission was observed in NaCeF(4):20 at% Tb with a quantum yield of 49%. The efficiency of energy transfer from Ce(3+) to Tb(3+) increases with the Tb(3+) doping concentration and reaches 95% for NaCeF(4):30 at% Tb. The ratio of Tb(3+) emission to Ce(3+) emission is sensitive to temperature, and the relative sensitivity was calculated to be 1.0% °C(−1) at 60 °C. The mechanisms for this thermal dependence were analyzed in terms of non-radiative relaxation and energy migration.