How crystallization additives govern halide perovskite grain growth

Area of Science:

• Materials Science
• Renewable Energy
• Solid-State Chemistry

Background:

• Liquid-phase preparation of perovskite solar cells is crucial for their potential.
• The relationship between precursor ink and perovskite formation is not well understood.
• Existing theories on nucleation and colloid formation are often unreliable.

Purpose of the Study:

• To elucidate the role of additives in perovskite crystallization.
• To establish a clear link between precursor ink, additives, and perovskite formation.
• To propose a unified framework for perovskite material design and process engineering.

Main Methods:

• Interdisciplinary study combining in situ and ex situ characterization.
• Device fabrication and testing.
• Computational simulations and density functional theory (DFT) calculations.

Main Results:

• Additives primarily facilitate grain coarsening by increasing ion mobility across grain boundaries, rather than impacting nucleation.
• A new concept explaining additive function was developed and validated across various additives and perovskite formulations.
• A direct link between additive engineering and perovskite post-processing was established.

Conclusions:

• Additives play a critical role in controlling perovskite grain growth and ion mobility.
• The proposed framework advances the understanding of perovskite formation and offers pathways for improved solar cell performance.
• This research bridges material design and process engineering for next-generation perovskite solar cells.