Detrimental Effect of Unreacted PbI2 on the Long-Term Stability of Perovskite Solar Cells

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

Research output: Contribution to journalArticlepeer-review

229 Citations (Scopus)


Excess/unreacted lead iodide (PbI2) 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 PbI2 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 PbI2 crystals under continuous light illumination. Unreacted PbI2 undergoes photodecomposition under illumination, resulting in the formation of lead and iodine in films. Thus, this photodecomposition of PbI2 is one of the main reasons for accelerated device degradation. Therefore, this work reveals that carefully controlling the formation of unreacted PbI2 crystals in perovskite films is very important to improve device operational stability for diverse opto-electronic applications in the future.

Original languageEnglish
Article number1905035
JournalAdvanced Materials
Issue number16
Publication statusPublished - Apr 1 2020

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering


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