Surface Reconstruction via Molten Chloride Salt for Efficient and Stable Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy

Background:

• Perovskite solar cells (PSCs) show high efficiency linked to optimized perovskite (PVK) film interfaces.
• Interfacial defects generated during PVK film deposition limit device performance.

Purpose of the Study:

• To develop a method for regulating interface properties and healing defects in PVK films.
• To improve the performance and stability of PSCs.

Main Methods:

• Utilizing an organic molten chloride salt, 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM), for surface reconstruction.
• Heating DMTMM to 110 °C to induce a phase transition to a liquid molten salt, facilitating coordination with unsaturated Pb2+ and halide vacancies.
• Forming a compact DMTMM interlayer after cooling to protect PVK films.

Main Results:

• The molten DMTMM effectively coordinated with unsaturated Pb2+ and halide vacancies, healing structural defects.
• The formed DMTMM interlayer protected PVK films from air degradation.
• DMTMM-treated MAPbI3-based PSCs achieved a champion power conversion efficiency (PCE) approaching 20% with enhanced stability.

Conclusions:

• Molten-salt-assisted surface reconstruction is a viable strategy for creating highly stable hybrid perovskite films.
• This approach offers a new pathway for developing high-performance PSCs.