Immediate and temporal enhancement of power conversion efficiency in surface-passivated perovskite solar cells

Yongyoon Cho, Jueming Bing, Hyung Do Kim, Yong Li, Jianghui Zheng, Shi Tang, Martin A. Green, Atsushi Wakamiya, Shujuan Huang, Hideo Ohkita*, Anita W. Y. Ho-Baillie*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)

Abstract

This work reports strategies for improving the power conversion efficiency (PCE) by capitalizing on temporal changes through the storage effect and immediate improvements by interface passivation. It is demonstrated that both strategies can be combined as shown by PCE improvement in passivated perovskite solar cells (PSCs) upon ambient storage because of trap density reduction. By analyzing the dominant charge recombination process, we find that lead-related traps in perovskite bulk, rather than at the surface, are the recombination centers in both as-fabricated and ambient-stored passivated PSCs. This emphasizes the necessity to reduce intrinsic defects in the perovskite bulk. Furthermore, storage causes temporal changes in band alignment even in passivated PSCs, contributing to PCE improvement. Building on these findings, composition engineering was employed to produce further immediate PCE improvements because of defect reduction in the bulk, achieving a PCE of 22.2%. These results show that understanding the dominant recombination mechanisms within a PSC is important to inform strategies for producing immediate and temporal PCE enhancements either by interface passivation, storage, composition engineering, or a combination of them all to fabricate highly efficient PSCs.

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Original languageEnglish
Pages (from-to)39178-39185
Number of pages8
JournalACS Applied Materials and Interfaces
Volume13
Issue number33
DOIs
Publication statusPublished - 25 Aug 2021

Keywords

  • perovskite
  • storage
  • aging
  • passivation
  • interface
  • bulk
  • recombination

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