Unrestricted Chiral Patterning by Laser Writing in Liquid Crystalline and Plasmonic Nanocomposite Thin Films

Obtaining hierarchical structures with arbitrarily controlled chirality remains a challenge since the commonly used chiral building blocks favor chiral randomness throughout length scales. Here, we obtain chiroptically bipolar patterned thin films by introducing an autonomous device for microscale photothermal re-melting of materials exhibiting chirality synchronization. The device operates on an algorithm that reads, identifies, and controls the recrystallization of the film, facilitating the homochiral growth of supramolecular organic helices. Owing to the molecular achirality of the individual molecules and local chirality synchronization, both handednesses of the helices are available, enabling unrestricted chiral writing in the film. The collective chiroptical response of assembled molecules is used for guiding the patterning process, thus creating a foundation for optically secured information. Established methodology enabled achieving dissymmetry factor values for circular dichroism a magnitude higher than previously reported, as confirmed with state-of-the-art, synchrotron-based Mueller matrix polarimetry. Moreover, we apply the developed method to nanocomposites comprising gold nanoparticles, providing the opportunity to tune the circular dichroism towards the plasmonic region. Our strategy uncovers the potential of photothermal processing by laser-directed melting, widening the selection of nanostructured materials with precisely designed chiroptical functionalities for photonic applications. This article is protected by copyright. All rights reserved.