Crystallization of FAPbI3: Polytypes and stacking faults

Area of Science:

• Materials Science
• Computational Chemistry
• Solid-State Physics

Background:

• Formamidinium lead iodide (FAPbI3) is a key material in perovskite solar cells.
• Understanding its crystallization is crucial for device stability and performance.
• Defects and polytypes can significantly impact material properties.

Purpose of the Study:

• To investigate the crystallization process of formamidinium lead iodide using molecular dynamics.
• To elucidate the formation mechanisms of intermediate defected structures.
• To identify and characterize different polytypes of formamidinium lead iodide.

Main Methods:

• All-atom molecular dynamics simulations.
• Simulations of crystal growth.
• Simulations of the delta-alpha phase transitions.

Main Results:

• Observed the formation of various stack-faulted intermediate defected structures.
• Identified multiple polytypes of formamidinium lead iodide during simulations.
• Provided atomic-level insights into the crystallization pathways.

Conclusions:

• The study reveals complex defect formation during formamidinium lead iodide crystallization.
• Different polytypes are accessible under simulated conditions.
• These findings contribute to a deeper understanding of formamidinium lead iodide structure-property relationships.