Self-Calibration Temperature Sensing and Color Tunable Emission in a Bimetallic Lanthanide Metal–Organic Framework

Temperature in various scientific and industrial applications requires accurate detection and measurement. Herein, a range of novel isostructural lanthanide-based metal–organic frameworks (Ln-MOFs), [Eu_xTb_2−x(3,5-pdc)₃(phen)₂(H₂O)₂]_n (x = 0, Tb-MOF; x = 2, Eu-MOF; x = 0.002, 0.010, 0.020, 0.040, 0.080, Eu_xTb_2−x-MOF), were solvothermally synthesized using 3,5-pyridinedicarboxylic acid (3,5-H₂pdc) and 1,10-phenanthroline (phen) as ligands. Based on binuclear second building units, Ln-MOFs exhibited 2D layered structure with sql topology. The luminescent properties of series Ln-MOFs show systematic tuning shifted from green to red by adjusting the ratio of Eu³⁺ to Tb³⁺. The temperature sensing experiments showed that Eu_0.020Tb_1.980-MOF exhibited self-calibration temperature response in a range of 293–413 K, achieving maximum relative sensitivity (S_r) 2.46%·K⁻¹ at 413 K, outscoring many state-of-the-art temperature sensors reported in literature. This study poses great promise of the newly designed Eu_0.020Tb_1.980-MOF for the ultra-sensitive temperature sensing in diverse and large-scale applications.