Inorganic mixed-halogen perovskites exhibit excellent photovoltaic properties and stability; yet, their photoelectric conversion efficiency is limited by inherent surface defects. In this work, we study the impact of defects on properties of CsPbI₂Br slabs using first-principles calculations, focusing on specific defects such as I vacancy (V_I), I interposition (I_i), and I substitution by Pb (Pb_I). Our findings reveal that these defects affect the geometric and optoelectronic properties as well as dynamics of charge carriers of slabs. We employ two theoretical frameworks (surface hopping and Redfield theory) of nonadiabatic molecular dynamics simulations to comprehensively study relaxation processes and obtain consistent results. The presence of V_I reduces carrier lifetimes, while the influence of Pb_I on carrier lifetimes is negligible. In contrast, I_i defects lead to prolonged carrier lifetimes. These insights provide valuable guidance for the rational design of perovskite photovoltaic devices, aiming to enhance their efficiency and stability.

中文翻译：

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表面缺陷对 CsPbI2Br 钙钛矿性能和动力学的影响：第一原理非绝热分子动力学模拟

无机混合卤钙钛矿表现出优异的光伏性能和稳定性；然而，它们的光电转换效率受到固有表面缺陷的限制。在这项工作中，我们使用第一性原理计算研究了缺陷对 CsPbI ₂ Br 板性能的影响，重点关注特定缺陷，例如 I 空位 (V _I )、I 插入 (I _i ) 和 I 被 Pb 替代 (Pb_我）。我们的研究结果表明，这些缺陷会影响板坯的几何和光电特性以及载流子的动力学。我们采用非绝热分子动力学模拟的两种理论框架（表面跳跃和雷德菲尔德理论）来全面研究弛豫过程并获得一致的结果。_VI的存在降低了载流子寿命，而Pb _I对载流子寿命的影响可以忽略不计。相反，I _i缺陷导致载流子寿命延长。这些见解为钙钛矿光伏器件的合理设计提供了宝贵的指导，旨在提高其效率和稳定性。