Inheriting the Characteristics of TADF Small Molecule by Side‐Chain Engineering Strategy to Enable Bluish‐Green Polymers with High PLQYs up to 74% and External Quantum Efficiency over 16% in Light‐Emitting Diodes

Thermally activated delayed fluorescence (TADF) polymers are designed and synthesized by grafting the TADF emitter to the side chain of the polycarbazole backbone. By employing these TADF polymers with large ratio of delayed fluorescence component and high photoluminescence quantum yield as the emitters, the solution-processed light-emitting diodes achieve a maximal external quantum efficiency of 16.1% at a luminance of around 100 cd m-2 .