We theoretically characterize the unusual white-light emission properties of two-dimensional (2D) hybrid organic inorganic perovskites with an APbX(4) structure (where A is a bidentate organic cation and X = Cl, Br). In addition to band structure calculations including corrections due to spin orbit couplings and electron hole interactions, a computationally intensive molecular cluster approach is exploited to describe the excitonic and polaronic properties of these 2D perovskites at the atomistic level. Upon adding or removing an electron from the neutral systems, we find that strongly localized small polarons form in the 2D clusters. The polaron charge density is distributed over just lattice sites, which is consistent with the calculated large polaron binding energies, on the order of similar to 0.4-1.2 eV.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by King Abdullah University of Science and Technology (KAUST) and by the Singapore National Research Foundation (NRF-CRPI4-2014-03). We gratefully thank the IT Research Computing Team and Supercomputing Laboratory at KAUST for computational and storage resources as well as precious assistance.