Halogen Engineering Enables Tunable Dielectric Response and Dimensional Regulation in Organic–Inorganic Hybrid Halides

Abstract

Organic–inorganic metal halides (OIMHs) have attracted great interest in the design of various functional materials due to their advantages of easy processability, rich structural diversity, and assembly flexibility. However, rational control of structural stacking patterns of the OIMHs for functional regulation has been a long-standing challenge. Particularly, little is known about the intrinsic relationship between structural dimensions and the dielectric response at the molecular scale. Here, we have investigated the modulation effect of cationic halogen engineering of (N,N-dimethylethanolamine)PbBr₃ on structural stacking, as well as its impact on thermal, electrical, and optical physical properties. Halogen regulation brings about varied structural stacking from a one-dimensional (1D) hexagonal perovskite structure and two-dimensional (2D) layered structure to an interlocking 1D chain structure. These varied attributes have been demonstrated to be closely related to molecular interactions in the crystal lattice, leading to variation in the sequential increase in phase transition temperature and differences in dielectric response, with the similar optical bandgaps that are mainly determined by inorganic frameworks. This study offers new insights into the structural stacking regulation and performance optimization of organic–inorganic hybrids.