Scientists Discover Chirality and Energy Transfer Amplified CPL in Composite Nanohelix
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, not only through chirality-based structural information but also 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, however, the multichannel communications including the chiral information were scarcely 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 in self-assembled nanohelix. This work was published on Nat. Commun..
They find that a chiral gelator could form chiral nanohelix through gelation and show both supramolecular chirality and circularly polarized luminescence (CPL). 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. More interestingly, 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, not only the chirality of gelator was transferred to the D-A nanohelix but also 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 (photo by Prof. LIU Minghua)
Prof. LIU minghua
Institute of Chemistry, Chinese Academy of Sciences