Halide perovskites - Non-Elaborate Posts - Post 1

 Halide perovskites are crystalline semiconductors of the general formula ABX₃, where A is a monovalent organic or inorganic cation (e.g. methylammonium CH₃NH₃⁺ (MA), formamidinium HC(NH₂)₂⁺ (FA), Cs⁺), B is a divalent metal cation (most commonly Pb²⁺ or Sn²⁺), and X is a halide anion (Cl⁻, Br⁻, I⁻).

In these materials the B-site cation is surrounded by six halide anions to form a BX₆ octahedron, and the A cations occupy the cavities between the corner-sharing octahedral This ABX₃ motif is derived from the same perovskite structure as CaTiO₃, but with oxygen replaced by a halide. For example, CH₃NH₃PbI₃ (MAPbI₃) consists of a 3D network of PbI₆ octahedra with CH₃NH₃⁺ in the interstitial cuboctahedral sites. Common A‐site ions include MA⁺, FA⁺ or Cs⁺; B‐site is typically Pb²⁺ or Sn²⁺; and X is I⁻, Br⁻ or Cl⁻.



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