Simultaneous Light‐Triggered Formation of Polymer Networks and Enhancement of Electrohydrodynamic Instabilities in Liquid Crystals for Versatile Energy‐Saving Smart Windows

Abstract Smart windows have come to the fore in modern buildings and intelligent information equipment drawing upon their dynamic control over light transmission. Liquid crystals tactfully manipulate light transmission depending on their microcosmic molecular orientations, emerging as new favorite functional materials for smart windows. However, most liquid crystal window technologies require continuous electricity for operation in luminous transparency and still perform a trade‐off between film formation performance and dimming functions. As key components of building structures, windows shall be kept transparent for an extended period. For the convenience of large‐scale processing, polymer matrices are indispensable. Given that, reverse‐operation‐mode dimming films, which are transparent to achieve daylighting in their natural or no power‐input states and become opaque to block sunlight through electric input on demand, are highly desired. Here, by introducing a photolabile amine, the synchronous light‐induced formation of polymer networks and enhancement of electrohydrodynamic instabilities in mesogenic materials is successfully executed. Relying on this creative and effective approach, reverse‐operation‐mode polymer network liquid crystal films having simultaneous modulation capability of visible light and near‐infrared light from solar irradiation are skillfully fabricated, promising applications in versatile energy‐saving smart windows.