Liquid crystal-induced tunable circular dichroism in CdSe and ZnSe nanoplatelets

• Published in: Journal of molecular liquids Vol. 398; p. 124187
• Main Authors: Tohgha, Urice N., Lee, Kyung Min, Slocik, Joseph M., Crenshaw, Ecklin M., Marsh, Zachary, Ovando, Oscar A., Govorov, Alexander O., Godman, Nicholas P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.03.2024
• Subjects: Chirality; Circular dichroism; Composites; Liquid crystal; Nanoplatelets; Nanoplatelets; Composites; Liquid crystal; Films; Chirality; Circular dichroism
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2024.124187

•Facile preparation of chiral liquid crystal-nanoplatelets composites.•Assembly of CdSe and ZnSe nanoplatelets in thermotropic liquid crystals.•Tunable exciton-induced circular dichroism in liquid crystal/nanoplatelets composites.•Chiral thin films (15 and 50 µm) of liquid crystal-CdSe nanocomposites. Induced circular dichroism in CdSe and ZnSe nanoplatelets (NPLs) was demonstrated using chiral thermotropic liquid crystals (LCs). Firstly, NPLs were easily dispersed in cholesteryl oleyl carbonate (COC) LC via a simple intercalation chemistry-based approach. Extensive circular dichroism (CD) studies showed remarkably strong and reversible chiroptical properties for these composites as a function of temperature. NPL-COC composites displayed strong exciton-induced CD as well as high anisotropy g-factor values (in the case of CdSe NPLs). Secondly, induced chirality in CdSe NPLs was also demonstrated using right-handed (RH) and left-handed (LH) blue phase LCs. LC-induced chirality in nanoparticles was corroborated by theoretical studies which revealed coupling between the chiral molecular excitons and nonchiral nanocrystals. The temperature-tunability is a useful tool to switch the chirality on/off. This study presents an alternative approach to realize exciton-induced tunable circular dichroism in nanomaterials.