Spatial Distribution of Lead Iodide and Local Passivation on Organo-Lead Halide Perovskite

Sheng Chen, Xiaoming Wen, Jae S. Yun, Shujuan Huang, Martin Green, Nam Joong Jeon, Woon Seok Yang, Jun Hong Noh, Jangwon Seo, Sang Il Seok, Anita Ho-Baillie

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


We identify nanoscale spatial distribution of PbI 2 on the (FAPbI 3 ) 0.85 (MAPbBr 3 ) 0.15 perovskite thin film and investigate the local passivation effect using confocal based optical microscopy of steady state and time-resolved photoluminescence (PL). Different from a typical scanning electron microscope (SEM) morphology study, confocal based PL spectroscopy and microscopy allow researchers to map the morphologies of both perovskite and PbI 2 grains simultaneously, by selectively detecting their characteristic fluorescent bands using band-pass filters. In this work, we compare the perovskite samples without and with excess PbI 2 incorporation and unambiguously reveal PbI 2 distribution for the PbI 2 -rich sample. In addition, using the nanoscale time-resolved PL technique we show that the PbI 2 -rich regions exhibit longer lifetime due to suppressed defect trapping, compared to the PbI 2 -poor regions. The measurement on the PbI 2 -rich sample indicates that the passivation effect of PbI 2 in perovskite film is effective, especially in localized regions. Hence, this finding is important for further improvement of the solar cells by considering the strategy of excess PbI 2 incorporation.

Original languageEnglish
Pages (from-to)6072-6078
Number of pages7
JournalACS Applied Materials and Interfaces
Issue number7
Publication statusPublished - 2017 Feb 22
Externally publishedYes


  • lifetime
  • nanoscale
  • passivation
  • PbI
  • perovskite

ASJC Scopus subject areas

  • Materials Science(all)

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