Aboma Merdasa
Researcher
Super-Resolution Luminescence Microspectroscopy Reveals the Mechanism of Photoinduced Degradation in CH3NH3PbI3 Perovskite Nanocrystals
Author
Summary, in English
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.
Department/s
- Chemical Physics
- NanoLund: Centre for Nanoscience
Publishing year
2016-04-22
Language
English
Pages
10711-10719
Publication/Series
Journal of Physical Chemistry C
Volume
120
Issue
19
Document type
Journal article
Publisher
The American Chemical Society (ACS)
Topic
- Materials Chemistry
- Condensed Matter Physics
Keywords
- perovskite
- photo-induced degradation
- photophysics
- blinking
- super-resolution microscopy
Status
Published
ISBN/ISSN/Other
- ISSN: 1932-7447