Ligand-induced chirality in asymmetric CdSe/CdS nanostructures: a close look at chiral tadpoles

Junjie Hao (1, 2, 3) , Yiwen Li (3, 4) , Jun Miao (5) , Rulin Liu (6) , Jiagen Li (6) , Haochen Liu (1) , Qiushi Wang (3) , Huan Liu (7) , Marie-Hélène Delville (2) , Tingchao He (7) , Kai Wang (1) , Xi Zhu (6) , Jiaji Cheng (3)

1 Department of Electrical and Electronic Engineering
2 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
3 School of Materials Science and Engineering
4 Department of Chemistry
5 IEK-5 - Institut für Energie- und Klimaforschung - Photovoltaik
6 AIRS - Shenzhen Institute of Artificial Intelligence and Robotics for Society
7 College of Physics and Optoelectronic Engineering

Ligand-induced chirality in asymmetric CdSe/CdS core–shell nanocrystals (NCs) has been extensively applied in chiral biosensors, regioselective syntheses and assemblies, circularly polarized luminescence (CPL), and chiroptic-based devices due to their excellent physiochemical properties, such as the tunable quantum confinement effects, surface functionality, and chemical stability. Herein, we present CdSe/CdS NCs with various morphologies such as nanoflowers, tadpoles, and dot/rods (DRs) with chirality induced by surface chiral ligands. The observed circular dichroism (CD) and CPL activities are closely associated with the geometrical characteristics of the nanostructures, such as the shell thickness and the aspect ratio of the CdSe/CdS NCs. Furthermore, in situ observations of the growth of tadpoles with a single tail indicate that the CD response is mainly attributed to the CdS shell, which has a maximum tail length of ∼45 nm (approximately λ/10 of the incident light wavelength). On the other hand, the CPL activity is only related to the CdSe core, and the activity benefits from a thin CdS shell with a relatively high photoluminescence quantum yield (QY). Further theoretical models demonstrated the aspect-ratio-dependent g-factor and QY variations in these asymmetric nanostructures. These findings provide insights into not only the asymmetric synthesis of CdSe/CdS NCs, but also the rational design of CdSe/CdS nanostructures with tunable CD and CPL activities.

Mots clés: ligand-induced chirality; CdSe/CdS core−shell nanocrystals; circularly polarized luminescence; circular dichroism; nanoflowers; tadpoles

Domaines: Matériaux

Junjie Hao, Yiwen Li, Jun Miao, Rulin Liu, Jiagen Li, et al.. Ligand-induced chirality in asymmetric CdSe/CdS nanostructures: a close look at chiral tadpoles. ACS Nano, 2020, 14 (8), pp.10346-10358. ⟨10.1021/acsnano.0c03909⟩. ⟨hal-02924169⟩