Surface-Activated Corrosion in Tin-Lead Halide Perovskite Solar Cells

Laura Mundt, Jinhui Tong, Axel Palmstrom, Sean Dunfield, Kai Zhu, Joseph Berry, Laura Schelhas, Erin Ratcliff

Research output: Contribution to journalArticlepeer-review

54 Scopus Citations

Abstract

Mixed tin-lead halide perovskite solar cells have promising power conversion efficiencies, but long-term stability is still a challenge. Herein we examine the stability of a 60:40 tin-lead perovskite to better understand diminished device performance upon thermal treatment, both in ambient and inert atmosphere. Operando X-ray diffraction shows a stable bulk structure of the perovskite absorber, leading to the hypothesis that surface chemistry dominates the degradation mechanism. X-ray photoelectron spectroscopy reveals two new observations post-thermal annealing that accompany previously reported Sn4+ evolution: (i) the formation of I3- intermediates preceding I2 loss at the surface and (ii) evidence of under-coordinated tin and lead surface sites (Snδ<2+ and Pbδ<2+, respectively) in inert and ambient conditions. These two species indicate an activated corrosion (i.e., both oxidation and reduction) process at the surface as a possible chemical pathway for degradation, which is expected to be accelerated under operando voltage and light biases.

Original languageAmerican English
Pages (from-to)3344-3351
Number of pages8
JournalACS Energy Letters
Volume5
Issue number11
DOIs
StatePublished - 2020

Bibliographical note

Publisher Copyright:
©

NREL Publication Number

  • NREL/JA-5900-78853

Keywords

  • corrosion
  • degradation
  • lead compounds
  • lead metallography
  • perovskite
  • photodegradation
  • surface chemistry
  • tin compounds
  • tin metallography
  • X-ray photoelectron spectroscopy

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