Direct Observation of Intragrain Defect Elimination in FAPbI 3 Perovskite Solar Cells by Two-Dimensional PEA 2 PbI 4

作者：Rui Zhi, Chenquan Yang, Mathias Uller Rothmann, Hong‐Qiang Du, Yang Jiang, Yue‐Yu Xu, Zhiwen Yin, Yanping Mo, Wei Dong, Guijie Liang, Udo Bach, Yi‐Bing Cheng, Wei Li · 发表于：ACS Energy Letters · 年份：2023 · DOI：10.1021/acsenergylett.3c00685 · 被引用次数：31 · 研究领域：Perovskite Materials and Applications、2D Materials and Applications、Quantum Dots Synthesis And Properties

Two-dimensional perovskites have widely been used to improve the efficiency and stability of perovskite solar cells and are generally believed to passivate defects at the grain boundaries of three-dimensional perovskites. Herein, we studied introducing various combinations of two-dimensional phenyl ethylammonium lead iodide (PEA 2 PbI 4 ) and methylammonium chloride (MACl) to the formamidinium lead iodide (FAPbI 3 ) precursor solution. Ultralow dose selected area electron diffraction studies prove that the high density of intragrain planar defects in FAPbI 3 can be strongly reduced by adding PEA 2 PbI 4 and fully eliminated by adding further MACl. Although PEA + is too large to incorporate into FAPbI 3, PEA 2 PbI 4 not only improves crystallization but also suppresses intragrain defect formation. As a result, a longer charge carrier lifetime, higher photoluminescence quantum yield, lower Urbach energy, and current–voltage hysteresis are achieved, resulting in a champion PCE of 23.69%, with an improvement of humidity stability.