Low-Bandgap Mixed Tin-Lead Iodide Perovskites with Reduced Methylammonium for Simultaneous Enhancement of Solar Cell Efficiency and Stability

Chongwen Li, Zhaoning Song, Cong Chen, Chuanxiao Xiao, Biswas Subedi, Steven Harvey, Niraj Shrestha, Kamala Subedi, Lei Chen, Dachang Liu, You Li, Yong-Wah Kim, Chun-Sheng Jiang, Michael Heben, Dewei Zhao, Randy Ellingson, Nikolas Podraza, Mowafak Al-Jassim, Yanfa Yan

Research output: Contribution to journalArticlepeer-review

169 Scopus Citations

Abstract

High-performance perovskite/perovskite tandem solar cells require high-efficiency and stable low-bandgap perovskite subcells. State-of-the-art low-bandgap mixed tin–lead iodide perovskite solar cells exhibit either a high power-conversion efficiency or improved stability, but not both. Here we report a two-step bilayer interdiffusion growth process to simultaneously meet both requirements for formamidinium-based low-bandgap mixed tin–lead iodide perovskite solar cells. The bilayer interdiffusion growth process allows for the formation of high-quality and large-grained perovskite films with only 10 mol% volatile methylammonium. Additionally, one-dimensional pyrrolidinium perovskite was applied to passivate the perovskite film and improve the junction quality, which resulted in a carrier lifetime of 1.1 μs and an open circuit voltage of 0.865 V for our perovskite film and device with a bandgap of 1.28 eV. Our strategies enabled a power-conversion efficiency of 20.4% for low-bandgap perovskite solar cells under AM 1.5G illumination. More importantly, an encapsulated device can retain 92% of its initial efficiency after 450 h of continuous 1 sun illumination.

Original languageAmerican English
Pages (from-to)768-776
Number of pages9
JournalNature Energy
Volume5
Issue number10
DOIs
StatePublished - 1 Oct 2020

Bibliographical note

Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.

NREL Publication Number

  • NREL/JA-5K00-76002

Keywords

  • 2-step bilayer interdiffusion growth (BIG) process
  • low-bandgap perovskite subcell
  • perovskite/perovskite tandem

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