Coordination Induction-Enhanced Thermally Activated Delayed Fluorescence for Silver(I) Complexes

Donor-acceptor (D-A) type nitrogen-containing compounds represent a key class of materials for constructing thermally activated delayed fluorescence (TADF) emitters. Achieving high-efficiency emission is the first issue in designing D-A-type TADF materials, particularly for applications in doped organic light-emitting diodes. Coordination-induced delayed fluorescence provides an effective strategy to regulate energy levels in these TADF materials, enabling efficient intramolecular ligand charge transfer (ILCT)-type emission. Moreover, metal coordination induces critical improvements, including enhanced spin-orbit coupling effect and shortened radiative lifetimes. Herein, we modulate the energy-level structure of yellow-emitting D-A-type hybrid fluorescence-TADF molecules via Ag(I) coordination, obtaining two Ag(I) complexes exhibiting ILCT-type emission. The coordination environment tunes the energy levels and reduces ΔEST, leading to a sharp enhancement in hybrid fluorescence-TADF performance. When doped in PMMA films, complex 1 achieves a PLQY of 98% (τF = 134 ns; τTADF = 2.7 μs), while complex 2 shows a PLQY of 46% (τF = 70.7 ns; τTADF = 2.0 μs). This work establishes a robust strategy to design novel TADF-active metal complexes.