Design challenges in the development of circularly polarized luminescence (CPL) materials are focused on balancing the luminescence dissymmetry factor (g_lum) and photoluminescence quantum yield (Φ_PL) by regulating the electric (μ) and magnetic (m) transition dipole moment vectors. Aiming at designing efficient CPL emitters and clarifying the chiroptical variation mechanism, herein, we present a double π-helix based on a cyclooctatetraene-embedded perylene diimide dimer that combines chirality with molecular entanglement and very high barriers for racemization. Through finely regulating the magnitudes of μ and m, the maximal dissymmetry factors |g_abs| and |g_lum| can be boosted to 0.035 and 0.030, respectively, as revealed by circular dichroism (CD) and CPL spectra. The results indicate a 3-fold improvement of g values and a modulated Φ_PL from 1a, 4, to 5 by nitrogen heteroannulation at the bay region. The CPL brightness (B_CPL) of 5 reaches a recorded value of up to 573.4 M^–1 cm^–1, among the highest values of chiral small molecules reported so far. This work has provided a comprehensive insight into a new class of chiral materials with high CPL activities, further laying molecular fundamentals for chiral optoelectronics.

中文翻译：

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通过双 π 螺旋和异环化提高圆偏振发光性能

圆偏振发光 (CPL) 材料开发中的设计挑战集中在通过调节电 ( μ ) 和磁 ( m ) 跃迁偶极矩矢量来平衡发光不对称因子 ( g _lum ) 和光致发光量子产率 (Φ _{PL )。}为了设计高效的 CPL 发射器并阐明手性变化机制，在此，我们提出了一种基于环辛四烯嵌入的苝二亚胺二聚体的双 π-螺旋结构，它结合了手性与分子纠缠和非常高的外消旋势垒。通过微调μ和m的大小，最大不对称因子 | G_腹肌| 和 | 克伦| _{_} 如圆二色性 (CD) 和 CPL 光谱所示，可以分别提高到 0.035 和 0.030。结果表明，通过在海湾地区的氮异环化， g值提高了 3 倍，调节的 Φ _PL从1a、4到5 。5的CPL亮度（B _CPL）达到最高573.4 M ^–1 cm ^{–1的记录值}，在迄今为止报道的手性小分子的最高值中。这项工作提供了对具有高 CPL 活性的新型手性材料的全面洞察，进一步奠定了手性光电子学的分子基础。