Enantioselective inorganic nanomaterials with near-infrared circular-polarized-activated photothermal response

Abstract

Chiral inorganic semiconductor materials have great potential in chiral catalysis, biomedicine and chiroptical devices. However, the narrow chiroptical response and weak chiroptical intensity limit their development. Herein, chiral CuS (D-/L-CuS) were prepared by a facile ligand exchange method using alanine (Ala) and penicillamine (Pen), respectively. The properties and stereostructures of chiral ligands resulted in enantioselectivity and chiroptical activity from ultraviolet to near-infrared (NIR) of chiral CuS. And the maximum of asymmetry factor |g| was up to 1.02 × 10-2, which is far higher than those of most chiral ligand-modified inorganic semiconductor nanomaterials. The NIR chiroptical activity facilitated photothermal performance, which could be tuned by circularly polarized light (CPL). D-CuS showed higher photothermal efficiency under right CPL radiation, while L-CuS showed higher photothermal efficiency under left CPL radiation. L-Pen-CuS exhibited the highest photothermal conversion efficiency of 22.18% under left CPL radiation. Moreover, the underlying mechanism of chirality in CuS was revealed for the first time. The coupling of amino acid ligands and CuS through Coulomb interactions allowed chiral transfer, and the orbital hybridization of chiral ligand orbitals with CuS molecular orbitals transferred chiral information. This work will further promote the understanding of induced chirality in inorganic semiconductor materials and the application of chiroptical-active inorganic semiconductor materials.