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, Przemyslaw Data, Youhei Takeda, Satoshi Minakata*

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review


A new class of thermally activated delayed fluorescent donor-acceptor-donor-acceptor (D-A-D-A) π-conjugated macrocycle comprised of two U-shaped electron-acceptors (dibenzo[a,j]phenazine) and two electron-donors (N,N'-diphenyl-p-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 has revealed significant effects of the structural cyclization of D-A-repeating structure, 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 analog (6.9%).
Original languageEnglish
JournalJournal of the American Chemical Society
Issue number3
Pages (from-to)1482-1491
Publication statusPublished - 2020

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