Molecular engineering of naphthalene spacers in low-dimensional perovskites

Hybrid organic–inorganic lead halide perovskites have drawn much interest due to their optical and electronic properties. The ability to fine-tune the structure by the organic component allows for obtaining a wide range of materials with various dimensionalities. Here, we combine experimental and theoretical work to investigate the structures and properties of a series of low-dimensional hybrid organic–inorganic perovskites, based on naphthalene ammonium cations, 2,6-diaminonaphthalene (2,6-DAN), 1-aminonaphthalene (1-AN) and 2-aminonaphthalene (2-AN). All materials exhibit edge- or face-sharing 1D chain structures. Compared to the 2D counterpart containing isomeric 1,5-diaminonaphthalene (1,5-DAN), 1D hybrid materials exhibit broadband light emission arising from the self-trapped excitons (STEs) owing to their highly distorted structure. This work expands the library of low-dimensional hybrid perovskites and opens new possibilities for obtaining broadband-light-emitting materials.