Symmetric Multi-Resonant TADF Emitters via Chiral Space Conjugation Toward Strong Chiroptical Responses and Narrowband Green Circularly Polarized Electroluminescence.

Yan, Zhiping; Lin, Jiaxin; Chen, Qishen; Zhuang, Xuming; Yuan, Li; Li, Zhiqiang; Wang, Zhiheng; Zheng, You-Xuan et al. · Adv Mater · 2026

basic_science · Level V

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Abstract

Developing thermally activated delayed fluorescence (TADF) materials with excellent chiroptical and photophysical properties is crucial for advancing optoelectronic applications. Herein, a chiral space conjugation strategy incorporating a typical [2.2]paracyclophane unit is proposed to construct a highly efficient chiral multi-resonant (MR) TADF emitter, R(S)-PCP-DBNO. Guided by the symmetry-matching rule, the molecular design achieves balanced contribution and optimal alignment of transition electric and magnetic dipole moments, resulting in a strong chiroptical response with a dissymmetry factor (|g<sub>abs</sub>|) exceeding 0.02. Meanwhile, owing to the special through-space conjugation, the enantiomer exhibits pure green emission with a peak at 526 nm, a narrow full-width at half-maximum of 26 nm, a Commission Internationale de I'Éclairage y coordinate of 0.70 and a quantum efficiency of 0.94 in toluene solution. When integrated into sensitized organic light-emitting diodes (OLEDs), R(S)-PCP-DBNO delivers a maximum luminance up to 241k cd·m<sup>-2</sup>, a maximum external quantum efficiency up to 29.4% and minimal efficiency roll-off. Furthermore, the devices demonstrate distinct circularly polarized electroluminescence, confirming the utility of this strategy for chiral MR-TADF emitters and circularly polarized OLEDs with simultaneous color purity, efficiency, and chiroptical functionality.