POS5-0798
Aggregation-Induced Supramolecular Chirality and NIR-Ⅱ Absorption in Quinoidal Chiral π-Conjugated Molecules for CPL Photodetection
When and Where
Nov 30, -0001
00:00 - 00:00
Presenter(s)
Jeongjin Hong (Gwangju Institute of Science and Technology)
Co-Author(s)
Abstract
Chiral π-conjugated molecules have attracted considerable attention as promising materials for circularly polarized light (CPL)-responsive organic optoelectronics due to their optical activity with tunable π-electronic structures. In particular, their electronic structures and intermolecular π- π interactions strongly affect aggregation, supramolecular assembly, and chiroptical properties. However, many conventional chiral π-conjugated molecules are based on benzenoid-type frameworks, where inter-ring torsional angles reduce backbone planarity and weaken ordered π-stacking. These structural limitations often confine their chiroptical activity to the UV-visible region. Extending chiroptical activity into the near-infrared (NIR) region is therefore important for expanding organic chiral materials toward advanced optoelectronic applications such as encrypted communication and CPL bioimaging. Thus, planar π-extended organic platforms that enable both NIR absorption and supramolecular chirality are highly desirable.
In this work, we designed and synthesized two quinoid-based chiral π-conjugated molecules, bQEDOT-(S)-Cn and bQPheDOT-(S)-Cn, containing different π-bridges and four chiral side chains. Their planar quinoid frameworks enabled low-energy absorption, while the chiral side chains induced supramolecular chirality upon aggregation. Both molecules showed aggregation-dependent long-wavelength absorption and chiroptical responses, which were enhanced in the film state. Notably, bQPheDOT-(S)-Cn showed an unusual NIR-II absorption band with a corresponding chiroptical response. Thermal annealing further enhanced these long-wavelength optical and chiroptical responses through film-state reorganization. Finally, photoconductor-type CPL photodetectors based on the chiral quinoid films exhibited long-wavelength CPL-responsive behavior, demonstrating their potential as a molecular platform for NIR CPL-responsive organic optoelectronic materials.
In this work, we designed and synthesized two quinoid-based chiral π-conjugated molecules, bQEDOT-(S)-Cn and bQPheDOT-(S)-Cn, containing different π-bridges and four chiral side chains. Their planar quinoid frameworks enabled low-energy absorption, while the chiral side chains induced supramolecular chirality upon aggregation. Both molecules showed aggregation-dependent long-wavelength absorption and chiroptical responses, which were enhanced in the film state. Notably, bQPheDOT-(S)-Cn showed an unusual NIR-II absorption band with a corresponding chiroptical response. Thermal annealing further enhanced these long-wavelength optical and chiroptical responses through film-state reorganization. Finally, photoconductor-type CPL photodetectors based on the chiral quinoid films exhibited long-wavelength CPL-responsive behavior, demonstrating their potential as a molecular platform for NIR CPL-responsive organic optoelectronic materials.
