Balanced Molecular Interactions with Mild Dipole Moment for Intermediate Suppressing in High Performance...

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Fabricating high-performance perovskite solar cells (PSCs) without antisolvents is challenging due to slow nucleation and intermediate compound formation.
• These intermediates hinder the crystallization of the desired α-FAPbI₃ phase, limiting device efficiency.

Purpose of the Study:

• To develop an antisolvent-free fabrication strategy for high-performance PSCs.
• To suppress solvated intermediates and promote the formation of high-quality α-FAPbI₃.

Main Methods:

• Employed a balanced molecular interaction strategy using additives with mild dipole moments (around 1.9 Debye).
• Systematically investigated dimethyl isophthalate (DMIP) derivatives with various substituents.
• Optimized the phase evolution process by identifying fluorine substituents as most effective.

Main Results:

• The optimized additive significantly shortened the time for α-phase dominance (t_d-α) from over 150 seconds to 23 seconds.
• Achieved a record power conversion efficiency of 26.28% for antisolvent-free regular PSCs using pure FAPbI₃.
• Demonstrated excellent device stability, retaining 93.7% efficiency after 1500 hours at 85°C and 90% after 1000 hours of maximum power point tracking.

Conclusions:

• The balanced molecular interaction strategy effectively suppresses solvated intermediates in antisolvent-free PSC fabrication.
• This approach enables faster, complete phase transformation to high-quality α-FAPbI₃, leading to record efficiencies.
• The developed method provides a promising pathway for stable and high-performance perovskite solar cells.