Hydrogels behave as potential candidates to investigate circularly polarized light (CP)-matter interaction, which however suffer from small sensitivity towards circular polarization. Here we report a general protocol to build hydrogels from π-conjugated amino acids with coassembled charge-transfer (CT) complexes, covering a wide scope of donors and acceptors, which were incorporated into stable hydrogel matrices. CT complexes formed block coassemblies with gelators, induced the emergence of macroscopic chiral helices, where efficient chirality transfer occurs to realize tunable Cotton effects from visible light to NIR-I region depending on the structures of CT pairs. The hybrid hydrogels showed tunable photothermal performances with excellent heating-cooling cycling durability. Circularly polarized NIR light selectively triggered gel-solution phase transition at different timescales. Left- and right-CP illumination generates up to 2.5 folds difference in gel collapse time that allows for direct discrimination by naked eyes.
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http://dx.doi.org/10.1002/anie.202214504 | DOI Listing |
Chemistry
December 2024
Tongji University, School of Chemical Science and Engineering, 1239 Siping Road, Shanghai, CHINA.
Upconverted circularly polarized luminescence (UC-CPL) active organic and organic-inorganic composite materials have garnered increasing attention due to their vast potential applications in areas such as 3D displays, encryptions, spintronics and optoelectronic devices. However, effective methods for fabricating chiral inorganic materials exhibiting UC-CPL remain a challenge. Herein, we propose an approach for the synthesis of UC-CPL active chiral mesostructured CeO2 powders (CMCs) via a hydrothermal growth method, using L/D-aspartic acid as symmetry-breaking and structure-directing agents.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT, United Kingdom.
We have measured the spin polarization of a slow positron beam via state-selective depopulation of 2^{3}S_{1} positronium atoms, generated by passing the beam through a gas cell. Our method employs circularly polarized microwave radiation to drive 2^{3}S_{1}→2^{3}P_{1} transitions, for which either Δm_{J}=+1 or Δm_{J}=-1, and relies on the fact that asymmetries between the two cases yield the underlying positron beam polarization. Using this technique we show that the polarization of a positron beam derived from a solid neon moderator may be increased from 30% to 90% by increasing the moderator thickness, with an associated reduction in beam intensity of 60%.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Shanghai Jiaotong University: Shanghai Jiao Tong University, School of Chemistry and Chemical Engineeringg, Dongchuan Road, Num 800, 200092, Shanghai, CHINA.
Circularly polarized luminescence (CPL) film attracted considerable attention in information storage and encryption, three-dimensional display, and chiral recognition. However, due to the limited molecular mobility within thin film, achieving a high asymmetry factor and non-contact modulation of CPL remain challenging. In this work, color-switchable homochiral CPL films with high luminescence asymmetry factor (glum~0.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Nankai University, School of Materials Science and Engineering, CHINA.
Chiral hybrid organic-inorganic metal halides (HOMHs) hold great promise in broad applications ranging from ferroelectrics, spintronics to nonlinear optics, owing to their broken inversion symmetry and tunable chiroptoelectronic properties. Typically, chiral HOMHs are constructed by chiral organic cations and metal anion polyhedra, with the latter regarded as optoelectronic active units. However, the primary design approaches are largely constrained to regulation of general components within structural formula.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
South China University of Technology School of Materials Science and Engineering, State Key Laboratory of Luminescent Materials and Devices and Institute of Polymer Optoelectronic Materials and Devices, 381 Wushan Road, 510640, Guangzhou, CHINA.
The exploration of circularly polarized luminescence is important for advancing display and lighting technologies. Herein, by utilizing isomeric molecular engineering, a novel series of chiral molecules are designed to exploit both thermally activated delayed fluorescence (TADF) and room-temperature phosphorescence (RTP) mechanisms for efficient luminescence. The cooperation of a small singlet-triplet energy gap, moderate spin-orbital coupling (SOC), and large oscillator strength enables efficient TADF emission, with photoluminescence quantum yields exceeding 90%.
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