论文标题
混合型金属卤化物钙钛矿中的不均匀缺陷分布
Inhomogeneous Defect Distribution in Mixed-Polytype Metal Halide Perovskites
论文作者
论文摘要
角，边缘和面部共享八面体网络之间的竞争是金属卤化物钙钛矿薄膜中相位不均匀性的原因。在这里，我们从第一原理材料建模中探索了CSPBI $ _3 $的立方和六边形多型型的连接处带电的碘空位分布和运输。我们预测面部共享区域中的缺陷形成能力较低，该区域与PB $ -I-I债券长度更长，并导致局部缺陷浓度增加一百万倍。这些缺陷被预测在面部共享区域更加可移动，而空位介导的扩散降低了活化能。我们得出的结论是，六边形相位夹杂物或界面将充当缺陷下沉，可以捕获电荷并增强基于钙钛矿的太阳能电池和电气设备中的电流 - 电压滞后。
The competition between corner, edge and face-sharing octahedral networks is a cause of phase inhomogeneity in metal halide perovskite thin-films. Here we probe the charged iodine vacancy distribution and transport at the junction between cubic and hexagonal polytypes of CsPbI$_3$ from first-principles materials modelling. We predict a lower defect formation energy in the face-sharing regions, which correlates with a longer Pb$-$I bond length and causes a million-fold increase in local defect concentration. These defects are predicted to be more mobile in the face-sharing regions with a reduced activation energy for vacancy-mediated diffusion. We conclude that hexagonal phase inclusions or interfaces will act as defect sinks that could trap charges and enhance current-voltage hysteresis in perovskite-based solar cells and electrical devices.
