2021/08/08 by Xuan Wang, Yehua Tang, Xuan, Wang +5
Engineering · Materials Science · #Crystal Structures and Properties #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Perovskite Materials and Applications #Solid-state spectroscopy and crystallography
paper · pdf · doi:10.48550/arxiv.2108.03597
openalex publication_date 2021/08/08 · openalex created_date 2022/10/01 · openalex updated_date 2026/07/28
As a possible alternative to organic-inorganic hybrid perovskite halide, inorganic Cs2SnI6 has drawn more and more research attention recently. In order to find more Cs2SnI6 derivatives as the potential solar cell absorber materials, I- ions in Cs2SnI6 are replaced by other halogen ions and forms the Cs2SnI6-nXn (X=F, Cl, Br; n=1~6) compounds, whose atomic structures, electronic structures and optical absorption are investigated by first principles calculation. When the alloying level n increases, the mean lattice constants, the weighted Sn-X and Cs-X bond lengths all decreases linearly; the bond length of each Sn-X diminishes slightly inside the octahedral structure; Eg of Cs2SnI6-nXn increases nonlinearly. Eleven Cs2SnI6-nXn compounds have an Eg between 1.0 eV and 2.0 eV and so can be potentially used as the light absorption layer of solar cells. Their partial DOS demonstrate that as the alloying level n increases, I 5p orbital in VBM and CBM is gradually substituted by Br 4p, or Cl 3p, or F 2p orbital. The eleven Cs2SnI6-nXn alloys all have a direct bandgap although the lattice distortion induced by the alloyed X- ion.