Cholesteric Liquid Crystal‐Mediated Chiral Plasmonic Films with Strong Chiroptical Response, Dynamic Tunability, and Reversible Thermal Reconfigurability

Abstract

AbstractChiral assemblies of plasmonic nanocrystals (NCs) are of immense interest due to their distinctive physicochemical characteristics and promising potential in future optoelectronic applications. Despite recent advances in the construction of chiral NC assemblies, most approaches have led to the formation of static irreversible structures with modest optical responses and limited configurational tunability. Herein, a way to prepare a thermally reconfigurable helical assembly of Au nanorods (AuNRs) with a strong chiroptical response is introduced by employing cholesteric liquid crystals (CLCs) as a chiral template. Circular dichroism (CD) spectroscopy and polarized optical microscopy are used to verify the strong chiroptical activity and dynamic optical tunability of chiral plasmonic film of AuNR–CLC composites and to unveil the interactions between constituents. For the system, chiral dopants are employed to induce strong helical procession along the hierarchical structure of the CLC template, resulting in a strong CD response, which can further be enhanced by increasing the amount of AuNRs. Furthermore, the thermotropic nature of the CLC template leads to the reversible on/off switching of the chiroptical responses of the system at a moderate temperature window with almost complete recovery of the original response, suggesting its feasibility as a promising material for chiral optoelectronic devices.