Understanding the Principles of Co-deposition of Mixed-SAMs in MAPbI₃-Based p-i-n Structure Perovskite Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Self-assembled monolayers (SAMs) integration in perovskite (PVK) solar cells faces processing challenges, limiting industrial scalability.
• Current methods require multiple steps, increasing complexity and cost for manufacturing PVK devices.

Purpose of the Study:

• To develop and investigate a single-step co-deposition strategy for SAMs and PVK films.
• To explore the influence of mixed SAMs properties (size, polarity, hydrophobicity) on PVK solar cell performance.
• To understand the fundamental principles governing the SAM/PVK co-deposition process.

Main Methods:

• Co-deposition of four commercially available SAM molecules (MeO-4PACz, Me-4PACz, Me-2PACz, 2PACz) in pairs with MAPbI3 precursor solutions.
• Fabrication and characterization of corresponding perovskite solar cell devices.
• Analysis of molecular interactions using quantum chemistry calculations, surface analysis, structural, and compositional analysis.

Main Results:

• A mixed SAMs strategy using MeO-4PACz + Me-4PACz achieved a power conversion efficiency of approximately 19% without additional passivation.
• The co-deposition process is significantly influenced by the interplay between the molecular size and polarity of the SAMs.
• Solvation behavior in the PVK precursor-DMF:DMSO solvent system dictates the binding strength of mixed SAMs to the ITO substrate.

Conclusions:

• The co-deposition of mixed SAMs offers a viable strategy to enhance the manufacturability of SAMs/PVK interfaces in solar cells.
• Understanding the molecular interactions, particularly size and polarity, is crucial for optimizing SAMs performance in PVK devices.
• This single-step approach demonstrates potential for efficient and scalable perovskite solar cell fabrication.