Ratiometric fluorescence temperature sensing of dual-lanthanide MOFs (Eu1-xTbx-BTC) prepared by solvothermal method

A series of bimetallic-organic frameworks (Eu 1-x Tb x -BTC) have been prepared via solvothermal method by using 1,3,5-benzenetricarboxylic acid as organic ligand, and confirmed by XRD patterns and FT-IR spectra. As x climbs up, the morphology of Eu 1-x Tb x -BTC evolves from micro-sticks gradually to microspheres with the diameter about 2–3 μm, among which Eu 0.1 Tb 0.9 -BTC displays the best luminescence performance under the excitation at 295 nm. Both the emission peaks located at 618 nm and 547 nm are rising with test temperature increasing instead of intrinsic thermal quenching. The fluorescence intensity ratio Δ of Eu 0.1 Tb 0.9 -BTC demonstrates a good linear fit in range of 293 K–473 K, combined with the maximum relative sensitivity ( Sr ) of 0.135%K −1 (293 K) and the temperature resolution ( δT ) range of 0.099 K–0.123 K. Finally, the five-cycle temperature sensing test proves Eu 0.1 Tb 0.9 -BTC has a reliable cycling and thermal stability.