Imprinting Chirality onto the Electronic States of Colloidal Perovskite Nanoplatelets

The direct synthesis of chiroptical organic–inorganic methylammonium lead bromide perovskite nanoplatelets that are passivated by R‐ or S‐phenylethylammonium ligands is reported. The circular dichroism spectra can be divided into two components: (1) a region associated with a charge transfer transition between the ligand and the nanoplatelet, 300–350 nm, and (2) a region corresponding to the excitonic absorption maximum of the perovskite, 400–450 nm. The temperature‐ and concentration‐dependent circular dichroism spectra indicate that the chiro‐optical response arises from chiral imprinting by the ligand on the electronic states of the quantum‐confined perovskite rather than chiral ligand‐induced stereoselective aggregation.