Deprotonation-Resistant Bimolecular Passivation Strategy for 26% Efficient and Stable Inverted Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Photovoltaics

Background:

• Surface passivation is crucial for improving perovskite solar cell (PSC) power conversion efficiency (PCE).
• Current passivation methods often use ammonium ligands susceptible to proton loss under operational stress (light and heat).

Purpose of the Study:

• To develop a novel dual-molecule surface passivation strategy for PSCs.
• To enhance the stability and PCE of perovskite solar cells by addressing ligand deprotonation issues.

Main Methods:

• A dual-molecule approach combining 4-methylpyridine-3-sulfonic acid (MPSA) and ethanolamine hydrochloride (EOACl) for surface passivation.
• MPSA's sulfonic acid group stabilizes ammonium cations by providing protons, reducing the deprotonation equilibrium constant.
• EOA⁺'s strong molecular dipole and high adsorption energy contribute to effective field-effect and chemical passivation.

Main Results:

• The dual-molecule passivation significantly reduced ligand deprotonation by over 10-fold.
• Perovskite solar cells achieved a peak PCE of 26.04%.
• Encapsulated devices maintained 91.2% of their initial PCE after 1100 hours of Maximum Power Point Tracking (MPPT) operation.
• Devices retained 90.3% of their efficiency after 800 hours of thermal aging at 85°C in the dark.

Conclusions:

• The MPSA and EOACl dual-molecule passivation strategy effectively enhances both the efficiency and operational stability of PSCs.
• This method offers a promising solution for developing durable and high-performance perovskite solar cells for practical applications.