Defect-induced local variation of crystal phase transition temperature in metal-halide perovskites

Research output: Contribution to journalArticle

Abstract

Solution-processed organometal halide perovskites are hybrid crystalline semiconductors highly interesting for low-cost and efficient optoelectronics. Their properties are dependent on the crystal structure. Literature shows a variety of crystal phase transition temperatures and often a spread of the transition over tens of degrees Kelvin. We explain this inconsistency by demonstrating that the temperature of the tetragonal-to-orthorhombic phase transition in methylammonium lead triiodide depends on the concentration and nature of local defects. Phase transition in individual nanowires was studied by photoluminescence microspectroscopy and super-resolution imaging. We propose that upon cooling from 160 to 140 K, domains of the crystal containing fewer defects stay in the tetragonal phase longer than highly defected domains that readily transform to the high bandgap orthorhombic phase at higher temperatures. The existence of relatively pure tetragonal domains during the phase transition leads to drastic photoluminescence enhancement, which is inhomogeneously distributed across perovskite microcrystals.

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Authors
Organisations
External organisations
  • Helmholtz-Zentrum Berlin for Materials and Energy
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
  • Materials Chemistry
Original languageEnglish
Article number34
JournalNature Communications
Volume8
Issue number1
StatePublished - 2017 Dec 1
Peer-reviewedYes