Accumulation of Deep Traps at Grain Boundaries in Halide Perovskites

Ji Sang Park, Joaquín Calbo, Young Kwang Jung, Lucy D. Whalley, Aron Walsh

Research output: Contribution to journalArticle

21 Citations (Scopus)


The behavior of grain boundaries in polycrystalline halide perovskite solar cells remains poorly understood. Whereas theoretical studies indicate that grain boundaries are not active for electron-hole recombination, there have been observations of higher nonradiative recombination rates involving these extended defects. We find that iodine interstitial defects, which have been established as a recombination center in bulk crystals, tend to segregate at planar defects in CsPbI3. First-principles calculations show that enhanced structural relaxation of the defects at grain boundaries results in increased stability (higher concentration) and deeper trap states (faster recombination). We show how the grain boundary can be partly passivated by halide mixing or extrinsic doping, which replaces or suppresses the formation of trap states close to the grain boundaries.

Original languageEnglish
Pages (from-to)1321-1327
Number of pages7
JournalACS Energy Letters
Issue number6
Publication statusPublished - 2019 Jun 14

All Science Journal Classification (ASJC) codes

  • Chemistry (miscellaneous)
  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Energy Engineering and Power Technology
  • Materials Chemistry

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