Self-Assembly of Chiral Ligands on 2D Semiconductor Nanoplatelets for High Circular Dichroism
Year: 2024
Type: article
Abstract: Group II–VI semiconductor nanoplatelets (NPLs) with atomically defined thicknesses and extended atomically flat (001) facets are used for ligand binding and chiro-optical effects. In this study, we demonstrate that tartrate ligands, anchored by two carboxylate groups, chelate the (001) facets of NPLs at an average ratio of one tartrate molecule to two cadmium (Cd) surface atoms. This assembly of chiral molecules on inorganic nanocrystals generates a circular dichroism g -factor as high as 1.3 × 10 –2 at the first excitonic transition wavelength of NPLs. Tartrate ligands induce an orthorhombic distortion of the initially “cubic” crystal structure, classifying the NPLs within the 222-point group. Unlike spherical nanocrystals, where it is difficult to discern whether chiral ligands affect only the surface atoms or the entire crystal structure, our findings unequivocally show that the crystal structure of NPLs is modified due to their thinness and atomically precise thickness. The in-plane lattice parameters experience compressive and tensile stresses, significantly splitting the heavy-hole and light-hole bands. Additionally, tartrate ligands adopt different conformations on the NPL surface over time, resulting in dynamic changes in the circular dichroism signal, including an inversion of its sign.
DOI: 10.1021/jacs.4c08981
Institutions: Centre National de la Recherche Scientifique, Université Paris Sciences et Lettres, Sorbonne Université, Laboratoire de Physique et d’Étude des Matériaux, ESPCI Paris, Institut de minéralogie, de physique des matériaux et de cosmochimie, Chimie Moléculaire, Macromoléculaire, Matériaux, Institut des NanoSciences de Paris, Commissariat à l'Énergie Atomique et aux Énergies Alternatives, CEA Grenoble, European Theoretical Spectroscopy Facility, Université Grenoble Alpes
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Awards: Nanocrystals-based short-wave Infrared Imaging, G434337789, Bright infrared light emitting diode with enhanced light-matter coupling, HgTe nanocrystals a new platform for THz optoelectronics, Photodetection in the Infrared with heavy metal-free QUANTum dots, Creating the new generation of 2D light emitters
OpenAlex ID: W4404018220