Effects of Potassium Treatment on SnO2 Electron Transport Layers for Improvements of Perovskite Solar Cells

SeongYeon Kim, Fei Zhang, Jinhui Tong, Xihan Chen, Enkhjargal Enkhbayar, Kai Zhu, JunHo Kim

Research output: Contribution to journalArticlepeer-review

16 Scopus Citations

Abstract

SnO2 has been studied intensively as an electron transport layer (ETL) for highly efficient metal halide perovskite solar cells. However, SnO2 ETL frequently exhibits defect-related issues associated with the bulk SnO2 and the perovskite/SnO2 interface, and to passivate the defect states potassium ion has been used. In order to investigate the passivation effect of potassium ion, we carried out KCl treatment on the solution-processed SnO2 ETL. It was found that KCl-treatment shifted up conduction band maximum and Fermi energy of SnO2, and reduced the band gap of perovskite absorber by K+ diffusion, which resulted in a better conduction band alignment at perovskite/SnO2. Admittance spectroscopy revealed that diffused K+ ions can passivate defects of the perovskite absorber layer. With the improvement of band alignment and defect passivation via the KCl treatment, the J-V hysteresis was almost eliminated and power conversion efficiency was much enhanced with improved open-circuit voltage and fill factor.

Original languageAmerican English
Pages (from-to)353-362
Number of pages10
JournalSolar Energy
Volume233
DOIs
StatePublished - Feb 2022

Bibliographical note

Publisher Copyright:
© 2022 International Solar Energy Society

NREL Publication Number

  • NREL/JA-5900-81964

Keywords

  • Defect passivation
  • Electron transport layer
  • K treatment
  • Perovskite
  • SnO
  • Solar cell

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