Morphology Formation Pathways in Solution-Processed Perovskite Thin Films

Area of Science:

• Materials Science
• Chemical Engineering
• Renewable Energy

Background:

• Perovskite solar cells utilize polycrystalline thin films for their active layer.
• Solution processing offers a scalable fabrication method for these films.
• The simultaneous processes of solvent evaporation and crystallization during thin film formation are not fully understood.

Purpose of the Study:

• To develop a geometrical model for understanding thin film formation.
• To investigate the interplay between solvent evaporation and crystal growth.
• To identify processing conditions that yield desired film morphologies.

Main Methods:

• Development of a geometrical model.
• Analysis of film formation mechanisms based on processing conditions.
• Investigation of the relationship between evaporation rate, crystal growth rate, and film morphology.

Main Results:

• Eleven distinct film formation pathways were identified.
• Four unique film morphologies were predicted by the model.
• Pinhole-free and flat films can be achieved by controlling evaporation and crystal growth rates.

Conclusions:

• The developed model provides insights into thin film formation during solution processing.
• Adapting process parameters to material properties allows for controlled film morphology.
• The model is applicable to various evaporating and crystallizing thin film systems.