Issue 9, 2019

Tunable circularly polarized luminescence from molecular assemblies of chiral AIEgens

Abstract

Circularly polarized luminescence (CPL) is important to chiral photonic technologies. In molecular systems, besides their intrinsic chemical structures, architectures of molecular assemblies at the mesoscopic scale also account for the final macroscopic CPL properties. Herein, tunable CPL responses can be induced through architectural regulation of these molecular assemblies in suspension and solid states. A liquid crystalline assembled system of DPCE-ECh exhibiting a smectic C* phase with a high dissymmetry factor (gCD = −0.20 and glum = +0.38) is reported. The intense and apparent CD and CPL of the film stem from the intrinsic helical structure of the molecular assembles with a weak contribution of Bragg reflection, where the helical axis is perpendicular to the optical axis and parallel to the direction of the glass substrate. To the best of our knowledge, this large glum factor is very rare for organic compounds even in the assembled state formed by annealing at the smectic liquid crystalline temperature. Interestingly, a strong CPL signal with a glum value of +0.18 is still recorded when DPCE-ECh is annealed in a chiral isotropic liquid (Iso*) state. On the other hand, DPCE-ACh can form two coexisting phases of chiral hexagonal and smectic liquid-crystalline phases due to intermolecular hydrogen bonding. The non-periodic molecular orientations of DPCE-ACh break its helical structure to give a weak negtive CPL signal of the order of 10−3. This work thus provides a new insight for developing efficient chiroptical materials in the aggregate state that have profound implications for high-performance CPL-based devices.

Graphical abstract: Tunable circularly polarized luminescence from molecular assemblies of chiral AIEgens

Supplementary files

Article information

Article type
Research Article
Submitted
23 май 2019
Accepted
07 юли 2019
First published
10 юли 2019

Mater. Chem. Front., 2019,3, 1768-1778

Tunable circularly polarized luminescence from molecular assemblies of chiral AIEgens

F. Song, Y. Cheng, Q. Liu, Z. Qiu, J. W. Y. Lam, L. Lin, F. Yang and B. Z. Tang, Mater. Chem. Front., 2019, 3, 1768 DOI: 10.1039/C9QM00332K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements