Evarestov R A, Kotomin E A, Senocrate A, Kremer R K, Maier J
Institute of Chemistry, St. Petersburg State University, Petrodvorets, Russia.
Max Planck Institute for Solid State Research, Stuttgart, Germany.
Phys Chem Chem Phys. 2020 Feb 19;22(7):3914-3920. doi: 10.1039/c9cp06322f.
First principles Density Functional Theory (DFT) hybrid functional PBESOL0 calculations of the atomic and electronic structure of perfect CsPbI3, CsPbBr3 and CsPbCl3 crystals, as well as defective CsPbI3 and CsPbBr3 crystals are performed and discussed. For the perfect structure, decomposition energy into binary compounds (CsX and PbX2) is calculated, and a stability trend of the form CsPbBr3 > CsPbI3 > CsPbCl3 is found. In addition, calculations of the temperature-dependent heat capacity are performed and shown to be in good agreement with experimental data. As far as the defect structure is considered, it is shown that interstitial halide atoms in CsPbBr3 do not tend to form di-halide dumbbells Br2- while such dimers are energetically favoured in CsPbI3, analogous to the well-known H-centers in alkali halides. In the case of CsPbBr3, a loose trimer configuration (Br32-) seems to be energetically preferred. The effects of crystalline symmetry and covalency are discussed, alongside the role of defects in recombination processes.
对完美的CsPbI3、CsPbBr3和CsPbCl3晶体以及有缺陷的CsPbI3和CsPbBr3晶体的原子和电子结构进行了第一性原理密度泛函理论（DFT）杂化泛函PBESOL0计算，并进行了讨论。对于完美结构，计算了分解为二元化合物（CsX和PbX2）的分解能，发现稳定性趋势为CsPbBr3 > CsPbI3 > CsPbCl3。此外，还进行了与温度相关的热容计算，结果表明与实验数据吻合良好。就缺陷结构而言，研究表明CsPbBr3中的间隙卤原子不会倾向于形成双卤哑铃状Br2-，而在CsPbI3中这种二聚体在能量上更有利，这类似于碱金属卤化物中著名的H中心。在CsPbBr3的情况下，一种松散的三聚体构型（Br32-）在能量上似乎更受青睐。讨论了晶体对称性和共价性的影响，以及缺陷在复合过程中的作用。
