Competition between Oxygen Curing and Ion Migration in MAPbI₃ Induced by Irradiation Exposure

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Organometal halide perovskites (OHPs) show potential for light-emission devices.
• Luminescence in OHPs is complex, influenced by crystal quality and environment.
• Understanding these factors is crucial for optimizing OHP performance.

Purpose of the Study:

• To investigate the dual role of light irradiation and environmental factors on the luminescence of methylammonium lead iodide (MAPbI3).
• To elucidate the mechanisms of oxygen curing of iodine vacancies and ion migration affecting luminescence.
• To provide insights into controlling luminescence in OHPs for device applications.

Main Methods:

• Low-temperature photoluminescence (PL) spectroscopy to detect iodine vacancies.
• Current-voltage (J-V) curve hysteresis analysis to probe ion migration.
• Excitation density-dependent PL lifetime measurements.
• Controlled oxygen environments and applied biases to modulate OHP properties.

Main Results:

• Light irradiation cures iodine vacancies (V_I) in MAPbI₃, increasing luminescence.
• Enhanced ion migration, triggered by irradiation or bias, leads to trap states and reduced luminescence.
• Evidence for V_I confirmed through PL spectra, J-V hysteresis, and PL lifetime studies.
• Tunable luminescence achieved by controlling oxygen curing and ion migration.

Conclusions:

• Luminescence in MAPbI₃ is critically dependent on the interplay between oxygen curing of iodine vacancies and ion migration.
• Light irradiation has a dual effect: beneficial curing and potentially detrimental ion migration.
• Controlling these competing factors is key to optimizing luminescence in organometal halide perovskites.