Intrinsic defects in primary halide perovskites: A first-principles study of the thermodynamic trends

作者：Haibo Xue, Geert Brocks, Shuxia Tao · 发表于：Physical Review Materials · 年份：2022 · DOI：10.1103/physrevmaterials.6.055402 · 被引用次数：56 · 研究领域：Perovskite Materials and Applications、Solid-state spectroscopy and crystallography、Optical properties and cooling technologies in crystalline materials

Defects in halide perovskites play an essential role in determining the efficiency and stability of the optoelectronic devices based on these materials. We present a systematic study of intrinsic point defects in six primary metal halide perovskites, ${\mathrm{MAPbI}}_{3}, {\mathrm{MAPbBr}}_{3}, {\mathrm{MAPbCl}}_{3}, {\mathrm{FAPbI}}_{3}, {\mathrm{CsPbI}}_{3}$, and ${\mathrm{MASnI}}_{3}$ (where MA denotes methylammonium and FA denotes formamidinium), based upon density functional theory calculations. Within a single computational scheme, using the $\text{SCAN}+\text{rVV10}$ functional, we compare the impact of changing anions and cations on the defect formation energies and the charge state transition levels in the six compounds, and identify the physical origins underlying the observed trends. Dominant defects in the lead iodide compounds are the ${A}^{+}$ cation interstitials ($A=\text{Cs}$, MA, FA), charge-compensated by ${\mathrm{I}}^{\ensuremath{-}}$ interstitials or lead $(2\ensuremath{-})$ vacancies. In the lead bromide and lead chloride compounds, halide interstitials are most prominent, and for ${\mathrm{MAPbCl}}_{3}$, the chlorine vacancy also becomes important. These trends can be explained in terms of the changes in electrostatic interactions and chemical bonding upon replacing cations and anions. Defect physics in ${\mathrm{MASnI}}_{3}$ is strongly dominated by tin $(2\ensuremath{-})$ vacancies, promoted by the easy oxidation of the tin. Intrinsically, all compo...