Interplay between structure and physical properties in organic-inorganic 2D perovskites

Organic-inorganic (hybrid) 2D perovskites feature unique structural characteristics related to the hybrid nature of their crystal lattice, which includes soft and dynamic lattice structure and organic-inorganic atom-thick interfaces.There is still little knowledge of the interplay between, on the one hand, their photo-excited states and electronic properties and, on the other hand, their structural characteristics. Here, using optical spectroscopy and 60-Tesla magneto-absorption supported by modelling, we report the dependence of the formation, dynamics, and recombination of exciton states on the structural and compositional details of hybrid 2D perovskites [Nature Communications 9, 2254, 2018 & Science 355, 1288, 2017]. First, our work reveals that the exciton properties are tailored by both the thickness of the 2D perovskites and the size of the organic molecules in the lattice. Second, we demonstrate the existence of unique electronic states located at the edges of the 2D perovskite layers, which result from local distortions of the lattice at the edges, and which promote exciton dissociation and localization. Finally, we will provides insight into the hetero-coupling between hybrid 2D perovskites and graphene-like layers such as graphene and transition metal dichalcogenides.