Key Laboratory of Organic Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Guangzhou 510640, China.
J Am Chem Soc. 2022 Jun 29;144(25):11397-11404. doi: 10.1021/jacs.2c04012. Epub 2022 Jun 17.
Design challenges in the development of circularly polarized luminescence (CPL) materials are focused on balancing the luminescence dissymmetry factor () and photoluminescence quantum yield (Φ) by regulating the electric () and magnetic () 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 and , the maximal dissymmetry factors || and || 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 values and a modulated Φ from , , to by nitrogen heteroannulation at the region. The CPL brightness () of reaches a recorded value of up to 573.4 M cm, 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.
设计圆偏振发光（CPL）材料时面临的挑战主要集中在通过调节电（）和磁（）跃迁偶极矩矢量来平衡发光不对称因子（）和光致发光量子产率（Φ）。为了设计高效 CPL 发射器并阐明手性变化机制，本文设计了一种基于双环辛四烯嵌入苝二酰亚胺二聚体的双π-螺旋结构，它将手性与分子缠结以及非常高的外消旋化势结合在一起。通过精细调节和的大小，可以将最大不对称因子||和||分别提高到 0.035 和 0.030，这可以通过圆二色（CD）和 CPL 光谱揭示出来。结果表明，通过在区域进行氮杂环化，可以将值提高 3 倍，并将Φ从、、调制到。的 CPL 亮度（）达到了 573.4 M cm 的记录值，是迄今为止报道的手性小分子中最高的 CPL 亮度之一。这项工作为具有高 CPL 活性的新型手性材料提供了全面的见解，进一步为手性光电奠定了分子基础。
