Impartation of Optical Activity from Chiral Ligands to Hybrid Perovskites via Virtual Photons

This is the authors' abstract. We don't add key points for this paper.

Abstract 2D hybrid organic–inorganic perovskites (HOIPs) with chiral ligands exhibit pronounced natural optical activity (NOA) in the vicinity of HOIPs’ exciton states, suggesting that the chiral ligands successfully extend their molecular NOA to the entire crystal. Using molecular quantum electrodynamics, we show that it is virtual photons that facilitate the impartation of NOA from the ligands to the HOIPs. The chiral ligands alter the photon-mediated dipole–dipole coupling between excitons in adjacent Pb–X layers by imposing a novel phase shift that depends on the ligand’s rotatory strength and excitation energy. This phase shift gives rise to a linear-Kz (K is the exciton’s center-of-mass wavevector with the z-axis normal to the 2D layers) term in the exciton dispersion and NOA. Our microscopic description, which is further corroborated by experimental measurements of a variety of HOIPs and chiral ligands, points the way to drastically enhance NOA in chiral HOIPs.