Mixed 3D–2D passivation treatment for mixed-cation lead mixed-halide perovskite solar cells for higher efficiency and better stability

Yongyoon Cho, Arman Mahboubi Soufiani, Jae Sung Yun, Jincheol Kim, Da Seul Lee, Jan Seidel, Xiaofan Deng, Martin A. Green, Shujuan Huang, Anita W. Y. Ho-Baillie*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

143 Citations (Scopus)

Abstract

Layered low-dimensional perovskite structures employing bulky organic ammonium cations have shown significant improvement on stability but poorer performance generally compared to their 3D counterparts. Here, a mixed passivation (MP) treatment is reported that uses a mixture of bulky organic ammonium iodide (iso-butylammonium iodide, iBAI) and formammidinium iodide (FAI), enhancing both power conversion efficiency and stability. Through a combination of inactivation of the interfacial trap sites, characterized by photoluminescence measurement, and formation of an interfacial energetic barrier by which ionic transport is reduced, demonstrated by Kelvin probe force microscopy, MP treatment of the perovskite/hole transport layer interface significantly suppresses photocurrent hysteresis. Using this MP treatment, the champion mixed-halide perovskite cell achieves a reverse scan and stabilized power conversion efficiency of 21.7%. Without encapsulation, the devices show excellent moisture stability, sustaining over 87% of the original performance after 38 d storage in ambient environment under 75 ± 20% relative humidity. This work shows that FAI/iBAI, is a new and promising material combination for passivating perovskite/selective-contact interfaces.

Original languageEnglish
Article number1703392
Number of pages10
JournalAdvanced Energy Materials
Volume8
Issue number20
DOIs
Publication statusPublished - 16 Jul 2018
Externally publishedYes

Keywords

  • 2D perovskite
  • mixed-cation perovskite solar cells
  • passivation
  • stability

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