Designing Ruddlesden–Popper Layered Perovskites through Their Organic Cations

Organic–inorganic layered perovskites were initially envisioned as materials for solar cells in view of their greater ambient stability compared to their 3D relatives. However, their major limitation was the insulating character of the bulky organic cations, especially in single-layer structures. This limitation was turned into an opportunity to explore organic molecules with different configurations, a journey that, to date, has delivered new materials for lighting, photocatalysis, chiro-optoelectronics, and ferroelectricity. In this Perspective, we aim to provide an outlook on the future challenges of using metal-halide Ruddlesden–Popper layered perovskites as scaffolds, including functional organic building blocks, for the creation of new hybrid materials. We envision that this research field can be empowered by establishing strong bridges with the organic chemistry and the machine-learning communities, which will help researchers to efficiently design new organic cations for exciting functionalities in this class of materials.