Constructing Highly Efficient Circularly Polarized Multiple‐Resonance Thermally Activated Delayed Fluorescence Materials with Intrinsically Helical Chirality

• Published in: Advanced materials (Weinheim) 2023-10, Vol.35 (42), p.e2305125-n/a
• Main Authors: Wang, Qingyang, Yuan, Li, Qu, Cheng, Huang, Tingting, Song, Xiaoxian, Xu, Yincai, Zheng, You‐Xuan, Wang, Yue
• Format: Article
• Language: English
• Subjects: Chirality; Circular polarization; circularly polarized luminescence; Electroluminescence; Emitters; Enantiomers; Fluorescence; Gels; Materials science; multiple resonance; Narrowband; narrowband emission; Organic light emitting diodes; Quantum efficiency; Resonance; thermally activated delayed fluorescence; Topology
• ISSN: 0935-9648; 1521-4095; 1521-4095
• DOI: 10.1002/adma.202305125

Advanced circularly polarized multiple‐resonance thermally activated delayed fluorescence (CP‐MR‐TADF) materials synergize the advantages of circularly polarized luminescence (CPL), narrowband emission, and the TADF characteristic, which can be fabricated into highly efficient circularly polarized organic light‐emitting diodes (CP‐OLEDs) with high color purity, directly facing the urgent market strategic demand of ultrahigh‐definition and 3D displays. In this work, based on an edge‐topology molecular‐engineering (ETME) strategy, a pair of high‐performance CP‐MR‐TADF enantiomers, (P and M)‐BN‐Py, is developed, which merges the intrinsically helical chirality into the MR framework. The optimized CP‐OLEDs with (P and M)‐BN‐Py emitters and the newly developed ambipolar transport host PhCbBCz exhibit pure green emission with sharp peaks of 532 nm, full‐width at half‐maximum (FWHM) of 37 nm, and Commission Internationale de L'Eclairage (CIE) coordinates of (0.29, 0.68). Importantly, they achieve remarkable maximum external quantum efficiencies (EQEs) of 30.6% and 29.2%, and clear circularly polarized electroluminescence (CPEL) signals with electroluminescence dissymmetry factors (gELs) of −4.37 × 10−4 and +4.35 × 10−4 for (P)‐BN‐Py and (M)‐BN‐Py, respectively. An edge‐topology molecular‐engineering strategy is proposed to construct circularly polarized multiple‐resonance thermally activated delayed fluorescence materials with intrinsically helical chirality. The enantiomers (P and M)‐BN‐Py‐based organic light‐emitting diodes exhibit pure‐green emission, with Commission Internationale de L’Eclairage coordinates of (0.29, 0.68), maximum external quantum efficiency exceeding 30%, and electroluminescence dissymmetry factor of approximately 4.40 × 10−4.