Supramolecular Chirality Synchronization in Thin Films of Plasmonic Nanocomposites

Abstract

Mirror symmetry breaking in materials is a fascinating phenomenon that has practical implications for various optoelectronic technologies. Chiral plasmonic materials are particularly appealing due to their strong and specific interactions with light. In this work we broaden the portfolio of available strategies toward the preparation of chiral plasmonic assemblies, by applying the principles of chirality synchronization—a phenomenon known for small molecules, which results in the formation of chiral domains from transiently chiral molecules. We report the controlled cocrystallization of 23 nm gold nanoparticles and liquid crystal molecules yielding domains made of highly ordered, helical nanofibers, preferentially twisted to the right or to the left within each domain. We confirmed that such micrometer sized domains exhibit strong, far-field circular dichroism (CD) signals, even though the bulk material is racemic. We further highlight the potential of the proposed approach to realize chiral plasmonic thin films by using a mechanical chirality discrimination method. Toward this end, we developed a rapid CD imaging technique based on the use of polarized light optical microscopy (POM), which enabled probing the CD signal with micrometer-scale resolution, despite of linear dichroism and birefringence in the sample. The developed methodology allows us to extend intrinsically local effects of chiral synchronization to the macroscopic scale, thereby broadening the available tools for chirality manipulation in chiral plasmonic systems.

Template-assisted self-assembly of achiral plasmonic nanoparticles into chiral structures

“…79 As a stimulating next step, the versatility of such approaches could unlock compatibility with semiconductor counterparts, achieving their incorporation into chiral plasmonic-excitonic systems. On the other hand, helical phases displaying tailored geometrical features with potential to act as chiral templates can be obtained in conned BCP systems 59 or in certain LC phases 93,94 that undergo spontaneous symmetry breaking. Their implementation will depend on the effective manipulation of handedness, which is one of the current major challenges in the eld.…”

Active Plasmonics with Responsive, Binary Assemblies of Gold Nanorods and Nanospheres

“…NRs were functionalized analogously to our previous work [ 19 ]. Briefly, the obtained NRs were centrifuged (14,000 rpm over 45 min) and redispersed in LC—DDT solution in THF in an ultrasonic bath.…”

Chiral plasmonic nanostructures: recent advances in their synthesis and applications

“…197 Actually, even racemic mixtures of liquid crystals can produce chiral materials on small scales: Szustakiewicz et al showed that the principles of chirality synchronization (a phenomenon known for small molecules, which results in the formation of chiral domains from transiently chiral molecules) could be used to control the co-crystallization of spherical gold nanoparticles and liquid crystal molecules, yielding domains composed of highly ordered helical nanofibers, preferentially twisted to the right or the left within each domain, even though the bulk material was racemic. 198 Peptides are also frequently employed to stabilize nanoparticles. 87,[199][200][201][202] The assembly of the nanoparticles is…”