Thermally Activated Delayed Fluorescent Donor–Acceptor–Donor–Acceptor π-Conjugated Macrocycle for Organic Light-Emitting Diodes
Saika Izumi, Heather F. Higginbotham, Aleksandra Nyga, Patrycja Stachelek, Norimitsu Tohnai, Piotr de Silva, Przemysław Data, Youhei Takeda, Satoshi Minakata
Abstract
-phenyelendiamine) has been rationally designed and successfully synthesized. The macrocyclic compound displayed polymorphs-dependent conformations and emission properties. Comparative studies on physicochemical properties of the macrocycle with a linear surrogate have revealed significant effects of the structural cyclization of the D-A-repeating unit, including more efficient thermally activated delayed fluorescence (TADF). Furthermore, an organic light-emitting diode (OLED) device fabricated with the macrocycle compound as the emitter has achieved a high external quantum efficiency (EQE) up to 11.6%, far exceeding the theoretical maximum (5%) of conventional fluorescent emitters and that with linear analogue (6.9%).