Chirality Transfer in Metal Halide Semiconductors

Chirality in metal halide semiconductors has emerged as a powerful strategy for nonlinear optoelectronics and spin-dependent functionalities. Herein we explore the mechanisms underpinning chirality transfer, namely, internal, external, remote, and reversible, within chiral hybrid metal halides. Internal chirality transfer is achieved by direct incorporation of chiral cations within the metal halide lattice, while external and remote mechanisms rely on chiral capping agents or proximity effects without altering the crystal lattice. Recent advancements highlight how structural rigidity, hydrogen bonding, and nanoconfinement enhance chiroptical responses, such as circular dichroism and circularly polarized luminescence. Strategies for tuning chirality transfer through modulation of the chiral cation nature, cation alloying, central metal selection, supramolecular assemblies, and encapsulation media are analyzed. Such approaches aim to increase the dissymmetry factors, thus providing a route to manipulate chirality transfer for developing next-generation spintronic and optoelectronic devices with tunable and scalable chiroptical properties.