Thermally Stable Perovskite Solar Cells by Systematic Molecular Design of the Hole-Transport Layer

Tracy H. Schloemer, Timothy S. Gehan, Jeffrey A. Christians, Deborah G. Mitchell, Alex Dixon, Zhen Li, Kai Zhu, Joseph J. Berry, Joseph M. Luther, Alan Sellinger

Research output: Contribution to journalArticlepeer-review

65 Scopus Citations

Abstract

With metal halide perovskite solar cells (PSCs) now reaching device efficiencies >23%, more emphasis must now shift toward addressing their device stability. Recently, a triarylamine-based organic hole-transport material (HTM) doped with its oxidized salt analogue (EH44/EH44-ox) led to unencapsulated PSCs with high stability in ambient conditions. Here we report criteria for triarylamine-based organic HTMs formulated with stable oxidized salts as hole-transport layer (HTL) for increased PSC thermal stability. The triarylamine-based dopants must contain at least two para-electron-donating groups for radical cation stabilization to prevent impurity formation that leads to reduced PSC performance. The stability of unencapsulated devices prepared using these new HTMs stressed under constant load and illumination far outperforms that of both EH44/EH44-ox and Li+-doped spiro-OMeTAD controls at 50 °C. Furthermore, the ability to mix and match these dopants with a nonidentical small-molecule-based HTL matrix broadens the design scope for highly stable and cost-effective PSCs without sacrificing performance.

Original languageAmerican English
Pages (from-to)473-482
Number of pages10
JournalACS Energy Letters
Volume4
Issue number2
DOIs
StatePublished - 8 Feb 2019

Bibliographical note

Publisher Copyright:
© 2019 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-71921

Keywords

  • hole transport material
  • metal halide
  • perovskite solar cells
  • stability

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