Buried interface modulation via PEDOT:PSS ionic exchange for the Sn-Pb mixed perovskite based solar cells

Sangheon Lee, Mun Young Woo, Changyong Kim, Kyung Won Kim, Hyemin Lee, Seok Beom Kang, Jeong Min Im, Min Ju Jeong, Yunhwa Hong, Joo Woong Yoon, Sung Yong Kim, Kwang Heo, Kai Zhu, Ji Sang Park, Jun Hong Noh, Dong Hoe Kim

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)


To apply Sn-Pb mixed perovskite solar cells for highly efficient single- or multi-junction devices, understanding device-specific buried interfaces is necessary. Poly [3,4-ethylenedioxythiophene]:poly[styrene sulfonate] (PEDOT:PSS) is primarily used as a hole transport layer in Sn-Pb mixed perovskite solar cells. However, the spatial heterogeneity of PEDOT:PSS, caused by its PEDOT-rich and PSS-rich domains, induces many defects at the buried interface in PEDOT:PSS/perovskite, which limits device performance. Here, we present ionic exchange (IE) of PEDOT:PSS via a combination of methylamine iodide (MAI) and dimethyl sulfoxide (DMSO). Through surface analyses and density functional theory (DFT) simulations, we confirm that the IE process preferentially form PEDOT-I and MA-PSS and that PSS-rich domains bind to DMSO. Thus, the spatial separation of PEDOT:PSS is solved, and the exchanged MA+ and I ions serve as a bridge between PEDOT:PSS and the perovskite, leading to improved physical, chemical, and electrical properties of the buried interface. The Sn-Pb mixed perovskite solar cells using IE-PEDOT:PSS achieve an improved efficiency of 21.3 % with an open-circuit voltage of 0.85 V and show better long-term stability. Additionally, IE-PEDOT:PSS works effectively in 2-terminal all-perovskite tandem devices, resulting in an improved efficiency of 23.5 % and high reproducibility.

Original languageEnglish
Article number147587
JournalChemical Engineering Journal
Publication statusPublished - 2024 Jan 1

Bibliographical note

Publisher Copyright:
© 2023 Elsevier B.V.


  • Buried interface
  • Ionic exchange
  • Sn-Pb mixed perovskite
  • Tandem solar cells

ASJC Scopus subject areas

  • General Chemistry
  • Environmental Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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