CsPbBr 3 Nanodiscs/Pb 4 S 3 Br 2 Nanocrystal Heterostructures: Shape Anisotropy for Tailoring Exciton–Phonon Coupling

Shape anisotropy in lead halide perovskite nanocrystals (NCs) provides strong crystallographic orientations for epitaxial growth chalcohalide NCs, yet the establishment of shape anisotropic heterostructures remains challenging, and their exciton states in the interfaces need a deeper understanding. Herein, shape anisotropic heterostructures where CsPbBr 3 nanodisks (NDs) are epitaxially grown along with Pb 4 S 3 Br 2 nanospheres or nanorods are reported, and varying the amount of Pb/S precursor allows for controlling the shape of Pb 4 S 3 Br 2 domain. The epitaxial growth orientation at the interfaces between the (100) plane of CsPbBr 3 NDs and the (101) plane of Pb 4 S 3 Br 2 has been established through structural characterizations. Significantly, the shape anisotropy of the two heterostructures induces the discrepancy of exciton states at the heterostructure interfaces, promoting exciton delocalization or localization at the interfaces of photogenerated excitons. These results illustrate that designing shape anisotropic heterostructures to tailor the exciton–phonon coupling holds significant potential to break through existing photodetection and photocatalytic applications.