In biological system, not only the beautiful chiral nanostructures such as DNA duplex and α-helical proteins were fabricated, but also some functions were run smoothly. In such system, transfer of information is multichannel, through chirality-based structural information as well as through ion-, electron-, light-based energy types.
Although some artificial chiroptical material systems have been developed to mimic sophisticated information communications as that in physiological systems through a molecular to supramolecular level by self-assembly strategy, the multichannel communications including the chiral information were rarely known.
Recently, a group led by Prof. LIU Minghua at Institute of Chemistry of Chinese Academy of Sciences and a group led by Prof. DUAN Pengfei at National Center for Nanoscience and Technology reported a donor-acceptor system that both chirality and energy transfer could be transferred and subsequently amplified the circularly polarized luminescence (CPL) in self-assembled nanohelix. This work was published on Nat. Commun.
Researchers found that a chiral gelator could form chiral nanohelix through gelation and show both supramolecular chirality and circularly polarized luminescence. When an achiral acceptor, 9, 10-bis(phenylethynyl)anthracene (BPEA), was mixed with the gelator molecule, a D-A composite nanohelix was formed.
Interestingly, chirality transfer could be realized by just weak π-π interaction other than common hydrogen bonding, electrostatic interaction or chain interdigitation. Besides, in the composite nanohelix assemblies, the acceptor BPEA could capture the energy from the chiral gel through highly efficient energy transfer. During such energy transfer, the chirality of gelator was transferred to the D-A nanohelix, and the circularly polarized fluorescence was significantly amplified.
Such energy transfer amplified circularly polarized fluorescence (ETACPL) provided a way to amplify the CPL. This work demonstrated that the multi-channel communications such as chirality and energy transfer could occur simultaneously and further amplify the chiroptical functions of materials.
Chirality and energy transfer amplified circularly polarized luminescence in composite nanohelix assemblies (Image by Prof. LIU Minghua)
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