CH $_3$ NH $_3$ PbI $_3$中的反相边界排斥载流子同时促进快速离子迁移
Antiphase boundary in CH$_3$NH$_3$PbI$_3$ repels charge carriers while promotes fast ion migrations
摘要：
有机-无机杂化钙钛矿（OIHP）中的缺陷严重影响其光电性能。识别和更好地理解OIHP中存在的缺陷是制造高性能钙钛矿太阳能电池的重要一步。然而，直接可视化的缺陷仍然是一个挑战，由于他们的灵敏度在电子显微镜表征的OIHP。本文利用低剂量扫描透射电子显微镜技术，观察到CH $_3$ NH $_3$ PbI $_3$（MAPbI $_3$）中普遍存在的反相界（APB），解析了它的原子结构，并将其与电子/离子活性和结构不稳定性联系起来。这种APB是由[PbI $_6$ ] $_4$ -八面体沿[100]/[010]方向的半晶胞位移引起的，导致从本体MAPbI $_3$中的共角[PbI $_6$ ] $_4$ -八面体转变为APB处的共边[PbI $_6$ ] $_4$ -八面体。基于确定的原子尺度配置，我们进一步进行密度泛函理论计算，并揭示了APB在MAPbI $_3$排斥电子和空穴，而作为一个快速的离子迁移通道，导致快速分解成PbI $_2$，这是不利于光电性能。这些发现提供了宝贵的见解OIHP的结构和光电性能之间的关系，并建议，控制APB是必不可少的，他们的稳定性。
英文摘要：
Defects in organic-inorganic hybrid perovskites (OIHPs) greatly influence their optoelectronic properties. Identification and better understanding of defects existing in OIHPs is an essential step towards fabricating high-performance perovskite solar cells. However, direct visualizing the defects is still a challenge for OIHPs due to their sensitivity during electron microscopy characterizations. Here, by using low dose scanning transmission electron microscopy techniques, we observe the common existence of antiphase boundary (APB) in CH$_3$NH$_3$PbI$_3$ (MAPbI$_3$), resolve its atomic structure, and correlate it to the electrical/ionic activities and structural instabilities. Such an APB is caused by the half-unit-cell shift of [PbI$_6$]$_4$-octahedron along the [100]/[010] direction, leading to the transformation from corner-sharing [PbI$_6$]$_4$-octahedron in bulk MAPbI$_3$ into edge-sharing ones at the APB. Based on the identified atomic-scale configuration, we further carry out density functional theory calculations and reveal that the APB in MAPbI$_3$ repels both electrons and holes while serves as a fast ion-migration channel, causing a rapid decomposition into PbI$_2$ that is detrimental to optoelectronic performance. These findings provide valuable insights into the relationships between structures and optoelectronic properties of OIHPs and suggest that controlling the APB is essential for their stability.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
