Molecular Pinning Effect in Composite Self-Assembled Monolayers Enabling Efficient Perovskite/TOPCon Tandem Solar...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Perovskite solar cells (PSCs) and tandem solar cells (TSCs) face challenges like interfacial losses, poor wettability, defect states, and energy level misalignment.
• Self-assembled monolayers (SAMs) are used to mitigate these issues, but further improvements are needed for efficient and durable devices.

Purpose of the Study:

• To introduce a novel composite SAM (Co-SAM) strategy using 4,4',4″,4‴-methanetetrayltetrabenzoic acid (4MA) and Me-4PACz.
• To enhance the performance and stability of wide bandgap perovskite solar cells (WBG PSCs) and perovskite/TOPCon TSCs by addressing interfacial issues.

Main Methods:

• A composite SAM (Co-SAM) strategy was employed, leveraging the molecular pinning effect of 4MA with Me-4PACz.
• This method improves monolayer uniformity on NiOₓ substrates, enhances wettability, and controls crystallization via Pb-O coordination and hydrogen bonding.
• The strategy focuses on passivating interface defects and optimizing energy-level alignment.

Main Results:

• Inverted 1.68 eV WBG PSCs achieved a champion efficiency of 23.52%.
• These WBG PSCs demonstrated excellent stability, retaining over 80% efficiency after 1000 hours of thermal aging at 85°C in a nitrogen atmosphere.
• The Co-SAM strategy improved the efficiency of 1 cm² TSCs to 32.26% (certified 32.10%), showcasing its versatility.

Conclusions:

• The Co-SAM strategy effectively addresses interfacial losses in perovskite photovoltaics.
• This approach leads to highly efficient and stable WBG PSCs and TSCs.
• The developed interfacial engineering method offers a scalable solution for advanced perovskite solar cell technologies.