Charge‐Transfer Complex Doped Photothermal Hydrogels for Discriminating Circularly Polarized Near‐Infrared Light.

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. [ABSTRACT FROM AUTHOR]