Yb³⁺‐Induced Bright Ligand Up‐Conversion Luminescence in 1D Coordination Polymers

Abstract Ln 3+ ‐induced ligand up‐conversion luminescence (UCL) in coordination polymers (CPs) effectively overcomes the inherent limitations of conventional organic UCL mechanisms. However, current research on UCL in Ln‐CPs has predominantly focused on the UCL of Ln 3 ⁺ ions themselves, while investigations into Ln 3 ⁺‐induced ligand UCL is overlooked in Ln‐CPs. Herein, by doping Yb 3 ⁺ into the Ln‐CPs of [Y 2 (FCA) 6 ] n 1 ) (FCA = 9‐fluorenone‐2‐carboxylic acid), Yb 3+ ‐doped 1D chain Ln‐CPs of [Y 2‐2x Yb 2x (FCA) 6 ] n (x = 0.2, 2 ) x = 0.5, 3 ) x = 0.7, 4 ) x = 0.9, 5 ) x = 1, 6 ) are prepared. Investigation of the UCL of FCA in these CPs reveals that Ln 3 ⁺‐induced ligand UCL are achieved for the first time. Notably, 4 not only displays bright UCL under both 10 and 15 W cm −2 excitation power of 980 nm laser but also achieves an absolute UCQY of 0.003 %, opening new avenues for the development of Ln‐CPs as UCL materials.