Visible‐Light Excited Luminescent Thermometer Based on Single Lanthanide Organic Frameworks

Isostructural lanthanide organic frameworks (Me 2 NH 2 ) 3 [Ln 3 (FDC) 4 (NO 3 ) 4 ]·4H 2 O (Ln = Eu ( 1 ), Gd ( 2 ), Tb ( 3 ), H 2 FDC = 9‐fluorenone‐2,7‐dicarboxylic acid), synthesized under solvothermal conditions, feature a Ln‐O‐C rod‐packing 3D framework. Time‐resolved luminescence studies show that in 1 the energy difference between the H 2 FDC triplet excited state (17794 cm −1 ) and the 5 D 0 Eu 3+ level (17241 cm −1 ) is small enough to...