Detrimental Effect of Unreacted PbI 2 on the Long‐Term Stability of Perovskite Solar Cells

作者：Ganbaatar Tumen‐Ulzii, Chuanjiang Qin, Dino Klotz, Matthew R. Leyden, Pangpang Wang, Morgan Auffray, Takashi Fujihara, Toshinori Matsushima, Jin‐Wook Lee, Sung‐Joon Lee, Yang Yang, Chihaya Adachi · 发表于：Advanced Materials · 年份：2020 · DOI：10.1002/adma.201905035 · 被引用次数：460 · 研究领域：Perovskite Materials and Applications、Chalcogenide Semiconductor Thin Films、Quantum Dots Synthesis And Properties

Abstract Excess/unreacted lead iodide (PbI 2 ) has been commonly used in perovskite films for the state‐of‐the‐art solar cell applications. However, an understanding of intrinsic degradation mechanisms of perovskite solar cells (PSCs) containing unreacted PbI 2 has been still insufficient and, therefore, needs to be clarified for better operational durability. Here, it is shown that degradation of PSCs is hastened by unreacted PbI 2 crystals under continuous light illumination. Unreacted PbI 2 undergoes photodecomposition under illumination, resulting in the formation of lead and iodine in films. Thus, this photodecomposition of PbI 2 is one of the main reasons for accelerated device degradation. Therefore, this work reveals that carefully controlling the formation of unreacted PbI 2 crystals in perovskite films is very important to improve device operational stability for diverse opto‐electronic applications in the future.