Light-enhanced oxygen degradation of MAPbBr₃ single crystal

Area of Science:

• Materials Science
• Optoelectronics
• Photochemistry

Background:

• Organometal halide perovskites show promise for optoelectronic devices.
• Material stability under environmental factors is crucial for commercialization.

Purpose of the Study:

• To investigate the synergistic degradation effects of simultaneous oxygen and light exposure on methylammonium lead bromide (MAPbBr3) single crystals.
• To understand the underlying mechanisms of accelerated degradation.

Main Methods:

• X-ray photoelectron spectroscopy (XPS) to monitor surface composition changes.
• Photoluminescence (PL) spectroscopy to assess optical properties.
• Scanning electron microscopy (SEM) and focused ion beam (FIB) for surface morphology analysis.
• Density functional theory (DFT) calculations to explore degradation mechanisms.

Main Results:

• Combined oxygen and light exposure significantly accelerated MAPbBr3 degradation compared to individual exposures.
• XPS revealed substantial loss of carbon, bromine, and nitrogen under co-exposure.
• Photoluminescence emission was significantly weakened, contrasting with enhancement from oxygen-only exposure.
• SEM/FIB showed pronounced surface roughening after co-exposure.
• DFT suggested superoxide formation and light-induced oxygen radicals as degradation drivers.

Conclusions:

• The synergistic effect of light and oxygen leads to accelerated degradation of MAPbBr3 perovskites.
• Light-induced oxygen radicals are a key factor in the enhanced decomposition pathway.
• Understanding these degradation mechanisms is vital for developing stable perovskite optoelectronic devices.