Three isostructural Eu³⁺/Tb³⁺ co-doped MOFs for wide-range ratiometric temperature sensing

Temperature is an important physical parameter in the fields of human life, scientific research and industrial applications, which requires accurate measurements in physiology and pathology. The fast, accurate, non-invasive and non-touch detection of temperature is one of the most important research findings of lanthanide MOFs (LnMOFs). Herein, three dual-emitting LnMOFs hybrids Tb_1-xEu_xL (x = 0.05, 0.1 and 0.2) were fabricated as ratiometric MOF thermometers. In the binary co-doped system, the special energy transfer method (Tb³⁺ → Eu³⁺) makes thermometers more sensitive and accurate. The detection range and maximum relative sensitivity (S_m) were investigated and compared with the reportorial materials. Luminescence explorations show that Tb_0.9Eu_0.1L can be used for sensing temperature in the range of 303-423 K and with a S_m of 1.75% K^-1 at 423 K. Furthermore, PXRD experiment indicates that Tb_0.9Eu_0.1L has outstanding stability under simulated physiological environment, which makes the application of Tb_0.9Eu_0.1L to the detection of temperature in biomedical systems a reality.