Interfacial Energetics Reversal Strategy for Efficient Perovskite Solar Cells.

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Nonradiative recombination at perovskite heterointerfaces hinders the efficiency of perovskite solar cells (PSCs).
• Developing strategies to minimize this recombination is crucial for advancing PSC technology.

Purpose of the Study:

• To develop a facile strategy for functionalizing perovskite heterointerfaces by reversing their surface energetics.
• To enhance hole extraction and reduce nonradiative recombination in PSCs.

Main Methods:

• Utilized trichloro[3-(pentafluorophenyl)propyl]silane (TPFS) as a surfactant to reverse perovskite surface energetics from n-type to p-type.
• Characterized surface energetics using ultraviolet and inverse photoelectron spectroscopies.
• Investigated the impact of TPFS on energy level alignment and defect density.

Main Results:

• TPFS successfully reversed perovskite surface energetics, creating an optimal energy level alignment with the hole transport layer.
• Demonstrated accelerated hole extraction across the heterointerface.
• Significantly diminished surface defect density, leading to minimized nonradiative recombination.
• Achieved a power conversion efficiency of 25.9% in PSCs with excellent reproducibility.
• Reported a nonradiative recombination-induced open-circuit voltage loss (qVoc) of only 57 meV, the lowest for n-i-p PSCs.

Conclusions:

• Interfacial energetics reversal via TPFS is an effective strategy to reduce nonradiative recombination in PSCs.
• The optimized energy level alignment and reduced defect density contribute to high power conversion efficiency.
• This approach offers a promising pathway for developing highly efficient and stable PSCs.