We report a comprehensive and systematic study of two halide perovskites by using density functional theory calculations. Two structurally different perovskites have been studied, which are cubic CH₃NH₃PbI₃ (MAPI) and HC(NH₂)₂PbI₃ (FAPI). We have used twenty-four exchange-correlation functionals, ranging from three LDA functionals, ten GGA functionals, seven MGGA and four hybrids among others have been tested, in order to determine the accuracy of these methods for the prediction of band gaps. Moreover, we have studied several possibilities to tackle the calculations of perovskites. That is, we have tested Numerical Atomic Orbitals with All Electron Relativistic calculations and compared to Plane Wave framework with pseudopotentials and relativistic corrections. Moreover, we have studied different k-points set, pseudopotentials types, with and without cell optimizations, with and without dispersion corrections and with and without Spin Orbit coupling. The results show that PBE and RPBE exhibit a good compromise between the accuracy of the results and computational demands.

我们通过使用密度泛函理论计算报告了两种卤化物钙钛矿的全面而系统的研究。两种结构不同的钙钛矿已经被研究，这是立方CH ₃ NH ₃碘化铅₃（MAPI）和HC（NH ₂）₂碘化铅₃（FAPI）。为了确定这些方法预测带隙的准确性，我们已经使用了二十四个交换相关函数，其中包括三个LDA函数，十个GGA函数，七个MGGA和四个混合函数。此外，我们研究了几种解决钙钛矿计算的方法。也就是说，我们已经用所有电子相对论计算测试了数字原子轨道，并将其与具有伪势和相对论校正的平面波框架进行了比较。此外，我们研究了不同的k点集，伪势类型，有无单元优化，有无色散校正，有无自旋轨道耦合。结果表明，PBE和RPBE在结果的准确性和计算要求之间表现出良好的折衷。