Boosting Circularly Polarized Luminescence Performance by a Double π-Helix and Heteroannulation

作者：Liu, Yujian; Ma, Zetong; Wang, Zhaohui; Jiang, Wei^*

来源：Journal of the American Chemical Society, 2022, 144(25): 11397-11404.

DOI：10.1021/jacs.2c04012

• CHIROPTICAL PROPERTIES
• DIPOLE-MOMENTS
• LIGHT
• SINGLE
• PLANAR

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 (Phi(PL)) by regulating the electric (mu) and magnetic (m) transition dipole moment vectors. Aiming at designing efficient CPL emitters and clarifying the chiroptical variation mechanism, herein, we present a double pi-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 mu and m, the maximal dissymmetry factors vertical bar g(abs)vertical bar and vertical bar g(lum)vertical bar 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 Phi(PL) from la, 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.

• 单位
  清华大学