Rethinking organic–inorganic interfacial steric hindrance in two-dimensional metal-halide perovskites

Layered organic–inorganic hybrid materials, particularly layered perovskites, are attractive in photonics and optoelectronics whose properties are strongly governed by long-range organic interactions. However, rational control of these interactions remains challenging due to the lack of suitable structural descriptors at the organic–inorganic interface. Here, we investigate hydrogen-bonded organic framework alignment in layered perovskites and show its tunability via both inorganic metal-halide and organic halide substitution, which modulates interfacial steric hindrance. This effect is quantified using the plane spacing between organic substituents and inorganic axial halides. Our results highlight interface engineering as a route to control long-range ordering in layered hybrids.