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Publication CIMI - Inorg. Chem., nov. 2021

Nouvel article de l'équipe CIMI dans Inorganic Chemistry:

From Zero- to One-Dimensional, Opportunities and Caveats of Hybrid Iodobismuthates for Optoelectronic Applications.

Alla Skorokhod, Nicolas Mercier, Magali Allain, Matthieu Manceau, Claudine Katan, and Mikael Kepenekian


The association of the electron acceptor 4,4′-amino-bipyridinium (AmV2+) dication and BiI3 in an acidic solution affords three organic–inorganic hybrid materials, (AmV)3(BiI6)2 (1), (AmV)2(Bi4I16) (2), and (AmV)BiI5 (3), whose structures are based on isolated BiI63– and Bi4I164– anion clusters in 1 and 2, respectively, and on a one-dimensional (1D) chain of trans-connected corner-sharing octahedra in 3. In contrast with known methylviologen-based hybrids, these compounds are more soluble in polar solvents, allowing thin film formation by spin-coating. (AmV)BiI5 exhibits a broad absorption band in the visible region leading to an optical bandgap of 1.54 eV and shows a PV effect as demonstrated by a significant open-circuit voltage close to 500 mV. The electronic structure of the three compounds has been investigated using first-principles calculations based on density functional theory (DFT). Unexpectedly, despite the trans-connected corner-shared octahedra, for (AmV)BiI5, the valence state shows no coupling along the wire direction, leading to a high effective mass for holes, while in contrast, the strong coupling between Bi 6px orbitals in the same direction at the conduction band minimum suggests excellent electron transport properties. This contributes to the low current output leading to the low efficiency of perovskite solar cells based on (AmV)BiI5. Further insight is provided for trans- and cis-MI5 1D model structures (M = Bi or Pb) based on DFT investigations.

DOI: 10.1021/acs.inorgchem.1c02384