Diffusion Enhancement in Highly Excited MAPbI₃ Perovskite Layers with Additives

Area of Science:

• Materials Science
• Solid-State Physics
• Optoelectronics

Background:

• Carrier mobility is a key factor for electronic device performance.
• Methylammonium lead iodide (MAPbI3) perovskite films are promising optoelectronic materials.
• Understanding carrier transport properties is crucial for optimizing perovskite devices.

Purpose of the Study:

• To investigate the impact of additives on carrier transport properties in wet-cast MAPbI3 perovskite films.
• To independently measure carrier diffusion coefficient and lifetime using the light-induced transient grating technique.
• To determine the influence of additives on carrier mobility and diffusion mechanisms.

Main Methods:

• Application of the light-induced transient grating technique.
• Utilizing a high excitation regime to isolate carrier diffusion effects.
• Analysis of carrier diffusion coefficient and lifetime in the presence and absence of additives.

Main Results:

• Additives led to a four-fold increase in the carrier diffusion coefficient.
• The study identified a reduction in localization center density as the cause for improved diffusion.
• Analysis confirmed that diffusion is primarily limited by localization effects.

Conclusions:

• Additives can significantly enhance carrier diffusion in wet-cast MAPbI3 films.
• The light-induced transient grating technique effectively probes carrier transport mechanisms.
• Carrier diffusion coefficient in these films could potentially be improved by an order of magnitude with technological advancements.