Plasmon-induced Circular Dichroism and Asymmetric Hot-electrons Generation Triggered by a Chiral Molecule for Polarization-dependent Chemical Reactions

Abstract

Performing chiral photodetection, photocatalysis or photochemical reactions at the molecular level has always been a nearly impossible task, due to the very low efficiency of the generated optical circular dichroism signals. On the contrary, chiral colloidal nanocrystals have been shown recently to offer a very large differential response to circularly polarized light. Such a response is able to generate hot-electrons with a very strong asymmetry, thus potentially able to perform the aforementioned tasks. In this paper, an intermediate picture is chosen, for which an achiral small assembly of identical particles triggered by a chiral molecule is able to generate large plasmon-induced circular dichroism (PICD), in turn able to generate the required asymmetry in the generation rates of hot-electrons. By performing Finite Difference Time Domain simulations based on the combination of a classical model of PICD generation and a quantum-based model of hot-electrons generation, the simple design of an achiral gold NPs’ dimer triggered by a chiral molecule located in the center and oriented with its transition electric dipole moment parallel to the dimer axis is shown to be able to generate a strong asymmetry in its HEs’ generation response. The PICDs and related hot-electrons generation rates increase as a function of volume, surface, respectively, of the considered systems, thereby providing a way to trigger chemical reactions.