Computational Study of Halide Perovskite-Derived A2BX6 Inorganic Compounds: Chemical Trends in Electronic Structure and Structural Stability

By Yaohang Cai, W. Xie, H. Ding, Yan Chen, T. Krishnamoorthy, Lydia Helena Wong, Nripan Mathews, S. Mhaisalkar, M. Sherburne, Mark Asta. 2017

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The electronic structure and energetic stability of A2BX6 halide compounds with the cubic and tetragonal variants of the perovskite-derived K2PtCl6 prototype structure are investigated computationally within the frameworks of density-functional-theory (DFT) and hybrid (HSE06) functionals. The HSE06 calculations are undertaken for seven known A2BX6 compounds with A = K, Rb, and Cs; and B = Sn, Pd, Pt, Te, and X = I. Trends in band gaps and energetic stability are identified, which are explored further employing DFT calculations over a larger range of chemistries, characterized by A = K, Rb, Cs, B = Si, Ge, Sn, Pb, Ni, Pd, Pt, Se, and Te; and X = Cl, Br, I. For the systems investigated in this work, the band gap increases from iodide to bromide to chloride. Further, variations in the A site cation influences the band gap as well as the preferred degree of tetragonal distortion. Smaller A site cations such as K and Rb favor tetragonal structural distortions, resulting in a slightly larger band gap. For varia...

Subfields: Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/9e291832c54b4bb3107f5a08610716dc1ed26b34