Incorporating Copper(I) Clusters into Lead Halide Perovskite through Mediation of Zwitterionic Linkers

Hybrid metal halide perovskites have attracted significant attention due to their outstanding chemical and structural versatility. Incorporating additional building blocks, such as large organic groups and organometallic clusters, provides additional pathways to manipulate the optoelectronic properties of perovskites. However, the bulky building blocks often struggle to cocrystallize with the lead halide framework, leading to undesirable crystal phase segregation or component exchange during cocrystallization. Here, we introduce a new zwitterionic-ligand-driven method for incorporating Cu-based clusters into perovskites. Mercaptoethylamine (MEA) serves as the bifunctional ligand to bridge the Cu(I) tetrahedral moieties and the perovskite scaffold, yielding a new bimetallic structure (MEA)4Cu2Pb3Br12. Combined X-ray-based characterizations and charge analysis affirm the antiferromagnetic coupling between the [CuS2Br2] tetrahedra, where the spin density is localized on the S atoms in a diradical form. The inclusion of Cu-based clusters introduces new acceptor energy levels that facilitate photocarrier separation and enable near-infrared light absorption.