MAPb(I_1−xBr_x)₃ is widely used as a window layer in tandem solar cells. Ion migration is one of the most important factors that results in phase separation in MAPb(I_1−xBr_x)₃ and eventually causes a decrease of cell performance. Recent research demonstrates that the doping of Cs⁺ and the formation of low-dimensional perovskite structures are effective means of inhibiting the migration. To investigate the causes of the migration and its inhibition mechanisms in hybrid halide perovskite materials, large-scale quantum dynamics simulations are conducted on MAPbI₃, MAPb(I_0.4Br_0.6)₃ and Cs_0.125MA_0.875Pb(I_0.4Br_0.6)₃, respectively. By tracking changes in the geometric structures of the perovskite materials before and after doping with Br⁻ and Cs⁺ in the dynamics processes, the precondition for the ion migration is firstly revealed. The dimension reduction of the perovskite skeleton structures by introducing Cs⁺ is observed. Furthermore, by combining observations with the variations of the band gap values in all the systems, the inhibition mechanisms of Cs⁺ doping on ion migration in MAPb(I_1−xBr_x)₃ are revealed.

中文翻译：

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通过量子动力学模拟研究掺Br的MAPbI3中的离子迁移及其抑制机理

MAPb（I _{1- x} Br _x）₃被广泛用作串联太阳能电池的窗口层。离子迁移是导致MAPb（I _{1- x} Br _x）₃发生相分离并最终导致电池性能下降的最重要因素之一。最近的研究表明，Cs ⁺的掺杂和低维钙钛矿结构的形成是抑制迁移的有效手段。为了研究杂化卤化物钙钛矿材料中迁移的原因及其抑制机理，对MAPbI ₃，MAPb（I _0.4 Br）进行了大规模量子动力学模拟。_0.6） ₃和Cs _0.125 MA _0.875 Pb（I _0.4 Br _0.6） ₃。通过之前和被Br掺杂后跟踪所述钙钛矿材料的几何结构的变化^-和Cs ⁺中的动态过程，对于离子迁移的前提首先显现出来。观察到通过引入Cs ⁺钙钛矿骨架结构的尺寸减小。此外，通过结合观察和所有系统中带隙值的变化，Cs ⁺掺杂对MAPb（I _{1- x} Br）中离子迁移的抑制机制_x） ₃被揭示。