Super-Resolution Luminescence Microspectroscopy Reveals the Mechanism of Photoinduced Degradation in CH3NH3PbI3 Perovskite Nanocrystals

Research output: Contribution to journalArticle

Abstract

Photoinduced degradation of individual methylammonium lead triiodide (MAPbI3) perovskite nanocrystals was studied using super-resolution luminescence microspectroscopy under intense light excitation. The photoluminescence (PL) intensity decrease and blue-shift of the PL spectrum up to 60 nm together with spatial shifts in the emission localization position up to a few hundred nanometers were visualized in real time. PL blinking was found to temporarily suspend the degradation process, indicating that the degradation needs a high concentration of mobile photogenerated charges to occur. We propose that the mechanistic process of degradation occurs as the three-dimensional MAPbI3 crystal structure smoothly collapses to the two-dimensional layered PbI2 structure. The degradation starts locally and then spreads over the whole crystal. The structural collapse is primarily due to migration of methylammonium ions (MA+), which distorts the lattice structure causing alterations to the Pb–I–Pb bond angle and in turn changes the effective band gap.

Details

Authors
Organisations
External organisations
  • Indian Institute of Technology, Roorkee
  • Nanjing University
  • Lund University
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Chemistry

Keywords

  • perovskite, photo-induced degradation, photophysics, blinking, super-resolution microscopy
Original languageEnglish
Pages (from-to)10711-10719
Number of pages9
JournalJournal of Physical Chemistry C
Volume120
Issue number19
StatePublished - 2016 Apr 22
Peer-reviewedYes