Visualizing phase segregation in mixed-halide perovskite single crystals

Wenxin Mao, Christopher R. Hall, Anthony S.R. Chesman, Craig Forsyth, Yi Bing Cheng, Noel W. Duffy, Trevor A. Smith, Udo Bach

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21 Citations (Scopus)


Mixed organolead halide perovskites (MOHPs), CH3NH3 Pb(BrxI1−x)3, have been shown to undergo phase segregation into iodide-rich domains under illumination, which presents a major challenge to their development for photovoltaic and light-emitting devices. Recent work suggested that phase-segregated domains are localized at crystal boundaries, driving investigations into the role of edge structure and the growth of larger crystals with reduced surface area. Herein, a method for growing large (30×30×1 μm3) monocrystalline MAPb(BrxI1−x)3 single crystals is presented. The direct visualization of the growth of nanocluster-like I-rich domains throughout the entire crystal revealed that grain boundaries are not required for this transformation. Narrowband fluorescence imaging and time-resolved spectroscopy provided new insight into the nature of the phase-segregated domains and the collective impact on the optoelectronic properties.

Original languageEnglish
Pages (from-to)2893-2898
Number of pages6
JournalAngewandte Chemie - International Edition
Issue number9
Publication statusPublished - 25 Feb 2019


  • lifetime
  • perovskites
  • phase segregation
  • photoluminescence
  • single crystals

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