Chiral Multidentate Ligand Facilitating Perovskite Nanocrystals with Circularly Polarized Luminescence and Chiral Assembly

Chiral ligand modification has emerged as a promising route to confer intrinsic chirality in perovskite nanocrystals (NCs), thereby imparting them with optically active properties and rendering great superiority in the next generation of circularly polarized luminescence. However, the functionalization of chiral ligand is not fully explored and the underlying mechanism governing chirality transfer remains elusive. Herein, tryptophan (Try), a naturally occurring chiral amino acid, is verified to serve as multidentate chiral ligands attaching on the surface of perovskite NCs. Such strong coordination favors the chirality imprinting on the electronic state of CsPbBr3, resulting in notable circular dichroism features and circularly polarized luminescence with a maximum glum of 2.3 x 10-3. It is intriguing that the intermolecular interaction between Try ligands anchored on two neighboring NCs contribute to chiral optical properties as well. The RDG-NCI analysis have confirmed the hydrogen bond between the amine and carboxylic groups on chiral Try, which may drive the chiral assembly of perovskite NCs. Chiral tryptophan is verified to be a multidentate ligand anchor on perovskite nanocrystals acting as the chiral donor, not only conferring perovskite chiral optical properties with tunable circularly polarized luminescence, but also inducing a chiral assembled morphology. These chiral nanocrystals provide an intriguing platform to investigate the intrinsic role and functionalization of chiral ligand in perovskite family.image