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Prototype Inorganic and Hybrid Halide Perovskite Derived A2SeX6 Compounds

A. S. Mulligan, G. T. Kent, A. Zohar, A. Brumberg, A. K. Cheetham, and R. Seshadri / Materials Department and Materials Research Laboratory / University of California, Santa Barbara, CA 93106

Halide perovskites are promising for applications in optoelectronic and photovoltaic (PV) devices.1 Besides conventional halide perovskites with the formula AMIIX3, vacancy-ordered double perovskites with the formula A2MIVX6 have been receiving increasing attention. These compounds resemble the double perovskites A2MIMIIIX6, with alternating M-sites vacant. The ability to engineer these materials for desired applications hinges on cultivating a comprehensive understanding of how their electronic structures impact relevant properties. A notable area of interest encompasses perovskite compounds that contain lone pairs which often do not impact their average structure but display signs of their presence locally.2 Vacancy-ordered halide double perovskites of 4s2 Se4+ with the formula A2SeX6 (A = CH3NH3+, K+, Rb+, Cs+; X = Cl–, Br–) exhibit crystal structures seemingly unaffected by the presence of Se lone pairs. Several of these compounds, especially with hybrid cations, have not previously been reported. The compounds were prepared using solution-based and hydrothermal methods. The poster will present structural and optical characterization, and band structures calculated using the Vienna Ab initio Simulation Package (VASP) software suite.

References:

  1. A. K. Jena, A. Kulkarni, T. Miyasaka, Halide perovskite photovoltaics: background, status, and future prospects, Chem. Rev 119 (2019) 3036-3103. DOI: 10.1021/acs.chemrev.8b00539
  2. G. Laurita and R. Seshadri, Chemistry, structure, and function of lone pairs in extended solids, Acc. Chem. Res. 55 (2022) 1004-1014. DOI: 10.1021/acs.accounts.1c00741