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

Abstract

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 × 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 defect-induced blue photoluminescence and circularly polarized luminescence of zero-dimensional Cs4PbBr6 perovskite nanocrystals

“…The chiral imprint on the surface of the perovskite NCs originates from the strong coordination. 11 In addition, our previous work found that defects in chiral perovskites can induce strong photoluminescence and exhibit a strong CPL response. 23 This result indicates that defects in chiral perovskites can give rise to strong photoluminescence and CPL because the chiral defects improve the recombination rate of the exciton.…”

“…9,10 (2) Chiral distortion can be realized by modifying the surface of achiral perovskite nanocrystals (NCs) with chiral molecules. 11–14 (3) A high CPL response can be obtained by grafting achiral perovskites onto chiral templates, such as spiral silica, 15,16 chiral gels, 17 and polymers. 18 Although chiral perovskites show a strong CD signal, symmetry breaking generates an indirect-bandgap character, which generally leads to the fact that chiral perovskites cannot exhibit an obvious CPL response.…”

“…16,17 Perovskite NCs can also exhibit CPL characteristics by attaching chiral ligands on their surface. 11–14,22 For example, Cao et al attaches the chiral amino acid ligands onto the surface of CsPbBr 3 perovskite NCs. The chiral imprint on the surface of the perovskite NCs originates from the strong coordination.…”