Enhanced visible light absorption in layered Cs₃Bi₂Br₉ through mixed-valence Sn(ii)/Sn(iv) doping.

ABSTRACT: Lead-free halides with perovskite-related structures, such as the vacancy-ordered perovskite Cs₃Bi₂Br₉, are of interest for photovoltaic and optoelectronic applications. We find that addition of SnBr₂ to the solution-phase synthesis of Cs₃Bi₂Br₉ leads to substitution of up to 7% of the Bi(iii) ions by equal quantities of Sn(ii) and Sn(iv). The nature of the substitutional defects was studied by X-ray diffraction, ¹³³Cs and ¹¹⁹Sn solid state NMR, X-ray photoelectron spectroscopy and density functional theory calculations. The resulting mixed-valence compounds show intense visible and near infrared absorption due to intervalence charge transfer, as well as electronic transitions to and from loc

SUBMITTER: Krajewska CJ 

PROVIDER: S-EPMC8597838 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature