CsSnI_(3)稳定性的第一性原理研究

First-principles Study of Stability in CsSnI_(3)

采用基于密度泛函的第一性原理方法,比较了CsSnI_(3)四种不同结构(α、β、γ和Y相)的本征稳定性,并进一步研究了H_(2)O分子的插入对两个室温相(γ和Y相)的影响。计算结果表明,在0 K下γ和Y相具有相对较低的总能量;将一个H2O分子插入到γ和Y相超胞中的插入能分别为-0.52和1.10 eV,表明γ相钙钛矿是亲水相,而非钙钛矿结构的Y相是疏水相。差分电荷密度分析结果表明,由于H2O分子中的O原子与Cs^(+)之间的强耦合以及H原子与I^(-)之间的氢键作用使得γ相结构发生明显变形。

The first-principle calculation based on density functional method was used to compare the intrinsic stability of four different structures of CsSnI_(3)(α,β,γand Y phase),and the effect of water molecule insertion on two room-temperature phases(γand Y phase)was further investigated.It was founded that the total energies of theγand the Y phase were relatively low at 0 K.The insertion energies of a water molecule in theγand Y phase supercells were-0.52 and 1.10 eV respectively,indicating that theγphase perovskite was hydrophilic,while the Y phase of the non-perovskite structure was hydrophobic.Differential charge density analysis showed that obvious deformation of theγphase structure was caused by the strong coupling between O atom and Cs^(+)and the hydrogen bond between H atom and I^(-).