Halide Mixing in Cs₂AgBi(I _x Br_1-x )₆ Double Perovskites: A Pathway to Tunable Excitonic Properties.

ABSTRACT: Cs₂AgBiBr₆ is an emerging double perovskite semiconductor with robust stability. However, its potential for photovoltaics is limited by its indirect band gap and localized electronic structure featuring a resonant exciton with a large binding energy. Cs₂AgBi(I _x Br_1-x )₆ nanocrystals with iodide concentrations of up to 100% were recently demonstrated, but an atomistic understanding of how halide mixing affects the electronic and excited-state structure is missing. Here, we use first-principles GW and Bethe-Salpeter Equation calculations to show that halide mixing leads to a pronounced change in the band gap and character of optical excitations. Exciton binding energies are reduced by up to a factor of 5, with s

SUBMITTER: Biega RI 

PROVIDER: S-EPMC11382272 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature