Chemical Mapping of Excitons in Halide Double Perovskites.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37656044.
- Also identified by DOI 10.1021/acs.nanolett.3c02285 and PMC identifier 10510582.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Halide double perovskites comprise an emerging class of semiconductors with tremendous chemical and electronic diversity. While their band structure features can be understood from frontier-orbital models, chemical intuition for optical excitations remains incomplete. Here, we use ab initio many-body perturbation theory within the <i>GW</i> and the Bethe-Salpeter equation approach to calculate excited-state properties of a representative range of Cs<sub>2</sub>BB'Cl<sub>6</sub> double perovskites. Our calculations reveal that double perovskites with different combinations of B and B' cations display a broad variety of electronic band structures and dielectric properties and form excitons with binding energies ranging over several orders of magnitude. We correlate these properties with the orbital-induced anisotropy of charge-carrier effective masses and the long-range behavior of the dielectric function by comparing them with the canonical conditions of the Wannier-Mott model. Furthermore, we derive chemically intuitive rules for predicting the nature of excitons in halide double perovskites using computationally inexpensive density functional theory calculations.