Sky-blue thermally activated delayed fluorescence polymers with π-interrupted polymer mainchain via Friedel-Crafts polycondensation

Abstract

Thermally activated delayed fluorescence (TADF) polymers have aroused persistent passion for the application of solution processed organic light emitting diodes (OLEDs). However, the lack of novel polymer structures and efficient TADF polymers proposes an imperative task to deal with. Herein, we designed and synthesized a series of TADF polymers by simple superacid-catalyzed polyhydroxyalkylation. The relatively high triplet energy level (2.88 eV) arising from the conjugation confined backbone effectively avoided energy back transfer from the TADF units to the mainchain. Combining with the side chain engineering strategy, the designed TADF polymers successfully inherited the feature from the dangled TADF moieties. With these TADF polymers as emitting layers, the solution processed polymer light emitting diodes (PLEDs) achieved a maximum external quantum efficiency (EQE) of 4.1% with CIE (Commission Internationale de L'Eclairage) coordinates of (0.26, 0.44).