Passivating Defects at the Bottom Interface of Perovskite by Ethylammonium to Improve the Performance of Perovskite Solar Cells

Jiahao Ren, Tanghao Liu, Bingchen He, Guangbao Wu, Hao Gu, Bingzhe Wang, Jielei Li, Yulin Mao, Shi Chen*, Guichuan Xing*

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

12 Citations (Scopus)

Abstract

The interface of perovskite solar cells (PSCs) plays a significant role in influencing their performance, yet there is still scarce research focusing on their difficult-to-expose bottom interfaces. Herein, ethylammonium bromide (EABr) is introduced into the bottom interface and its passivation effects are studied directly. First, EABr can improve substrate wettability, which is beneficial for the perovskite-film deposition. By lifting off the perovskite film spontaneously from the substrate, it is found that EABr can significantly reduce the amount of unreacted PbI2 at the bottom interface. These PbI2 crystals have been recently identified as a major defect source and degradation site for perovskite film. Meanwhile, EABr also lifts the valence band maximum at the bottom side of perovskite from -5.38 to -5.09 eV, facilitating better hole transfer. Such a improvement is also verified by the study of charge carrier dynamics. Through introducing EABr, all photovoltaic parameters of the inverted PSCs are improved, and their power conversion efficiency (PCE) increases from 20.41% to 21.06%. The study highlights the importance of direct characterization of the bottom interface for a better passivation effect.
Original languageEnglish
Article number2203536
JournalSmall
Volume18
Issue number47
Early online date13 Oct 2022
DOIs
Publication statusPublished - 24 Nov 2022

Scopus Subject Areas

  • Engineering (miscellaneous)
  • Chemistry(all)
  • Materials Science(all)
  • Biotechnology
  • Biomaterials

User-Defined Keywords

  • ammonium group
  • bottom interface
  • defect passivation
  • energy-level alignment
  • lead iodide residual

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