Layered Halide Double Perovskites: Dimensional Reduction of Cs2AgBiBr6

• DOI: 10.1021/jacs.8b01543
• Publication Date: 2018-03-25T14:08:59Z
• Authors: Bridget A. Connor; Linn Leppert; Matthew D. Smith; Jeffrey B. Neaton; Hemamala I. Karun...
• Keywords: Lattice (music)

We investigate the consequences of dimensional confinement on halide double perovskites by synthesizing two-dimensional analogues recently reported three-dimensional perovskite Cs2AgBiBr6. The layered (BA)4AgBiBr8 (1) and (BA)2CsAgBiBr7 (2) (BA = CH3(CH2)3NH3+) feature metal-halide sheets mono bilayer thickness, respectively, where ordered double-perovskite lattice is partitioned organic cations. Electronic structure calculations indicate that indirect bandgap Cs2AgBiBr6 becomes direct when infinitely thick inorganic reduced to monolayer thickness. Calculations model systems allow us separate effects reduction from those accompanying structural distortions in sublattice. Detailed optical characterization shows photophysical properties 1 2 are markedly different than their well-studied lead-halide analogs. Hybrid derivatives substantially expand substitutional flexibility encompass greater compositional electronic diversity.