Lanthanide(III) Ions-Induced Antenna Effect Switch Regulates Smart Sensing and Photodynamic Sterilization of Ln-MOFs

2,5-Furandicarboxylic acid was used as a linker to react with Ln(NO₃)₃·6H₂O (Ln = Tb, Eu, Gd, and Dy) under solvothermal conditions to obtain lanthanide metal organic frameworks (<b>Ln</b>_<b>4</b><b>-MOFs</b>) with Ln₄L₉ as the secondary building unit (SBU). <b>Tb</b>_<b>4</b><b>-MOF</b> and <b>Eu</b>_<b>4</b><b>-MOF</b> exhibit distinct characteristic fingerprint emissions of Tb(III) ions and Eu(III) ions, respectively. When formulated into luminescent inks and applied onto predrawn patterns, they retain their vibrant characteristic emissions. The thermal quenching effect on the emission peaks of <b>Eu</b>_<b>4</b><b>-MOF</b> is insignificant in the low-temperature range, whereas it becomes pronounced in the high-temperature range. It is noteworthy that <b>Eu</b>_<b>4</b><b>-MOF</b> demonstrates pronounced luminescence quenching-based optical sensing for both Al(III) and Cu(II) ions, with detection limits as low as 86.54 nM and 61.53 nM, respectively. In addition, the DCFH solution containing <b>Gd</b>_<b>4</b><b>-MOF</b> showed a fluorescence enhancement factor of 59.3 times under 27 s of light irradiation, indicating that <b>Gd</b>_<b>4</b><b>-MOF</b> can generate a large amount of ROS. <b>Gd</b>_<b>4</b><b>-MOF</b> has significant photodynamic sterilization effects on common Gram-negative/Gram-positive bacteria, with inhibition zones of 1.74 and 1.99 cm, respectively. This work not only provides a vivid example for the controllable construction of lanthanide MOFs with bright luminescence, but also opens up new horizons for the expansion of multifunctional lanthanide complexes.