TADF Emission in Supramolecular Assemblies through Cooperativity and Polymorphism

Supramolecular assemblies exhibiting thermally activated delayed fluorescence (TADF) represent a still poorly explored field of research. Here, the photophysical properties of a novel anthraquinone-based dye 1 emitting in a wide range between orange and near-infrared, depending on the aggregation form (polymorphs or fibers) are investigated. 1 exhibits a near orthogonal D-A-D molecular structure with a dimethylated phenyl ring between D and A, which is not hampering the molecular packing. The self-assembly mechanism exhibits a cooperative process regardless of the encumbered phenyl units, allowing the formation of emitting fibers and polymorphs with TADF character. Computational investigations carried out in solution and in the solid state support the interpretation of the photophysical data and reveal the role of the environment. The possibility of applying these TADF fibers is finally demonstrated in solution-processed organic light-emitting diodes.