Co-Self-Assembled Interface Engineering Assisted for Bend-Resistant and Efficient Flexible Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy

Background:

• Flexible perovskite solar cells (F-PSCs) offer excellent mechanical flexibility but are limited by interface defects.
• Defects at the bottom interface of NiO_x/perovskite (PVK) hinder device performance improvements.

Purpose of the Study:

• To engineer the NiO_x/PVK interface in F-PSCs using a co-self-assembled monolayer (Co-SAM) strategy.
• To improve surface uniformity, hydrophilicity, and perovskite crystal orientation at the interface.
• To mitigate interfacial defects and enhance charge transfer for better device performance and stability.

Main Methods:

• Implemented a Co-SAM strategy by integrating 4-nitrophenyl phosphate (PNPP) with [4-(3,6-dimethyl-9H-carbazol-9-yl) butyl] phosphonic acid (Me-4PACz).
• Engineered the NiO_x/PVK interface to enhance surface properties and promote favorable perovskite growth.
• Investigated the role of PNPP in defect mitigation and PbI₂ capture.

Main Results:

• Achieved enhanced surface uniformity and hydrophilicity of the NiO_x/Me-4PACz interface.
• Promoted favorable crystal orientation of perovskite layers.
• Significantly improved interfacial charge transfer efficiency, boosting F-PSC efficiency from 21.46% to 23.66%.
• Demonstrated enhanced mechanical stability, retaining 80% efficiency after 10,000 bending cycles.
• Showcased PNPP's capacity for PbI₂ capture, indicating potential for reduced lead leakage.

Conclusions:

• The Co-SAM engineering strategy effectively addresses bottom-interface defects in F-PSCs.
• Improved interface quality leads to higher power conversion efficiency and enhanced operational stability.
• PNPP integration offers a promising approach for developing more stable and potentially lead-leakage-resistant perovskite solar cells.