High-Efficiency Thickness-Insensitive Organic Solar Cells with an Insulating Polymer.

Area of Science:

• Materials Science
• Organic Electronics
• Renewable Energy

Background:

• Achieving high-efficiency thick-film organic solar cells (OSCs) for roll-to-roll printing remains a challenge.
• Diluting bulk heterojunction (BHJ) active layers with insulating polymers can optimize charge transport and reduce defects.

Purpose of the Study:

• To investigate the use of insulating polypropylene (PP) in a PM6:Y6 non-fullerene system for fabricating efficient thick-film OSCs.
• To enhance molecular interactions and charge transport properties in BHJ films.

Main Methods:

• Incorporation of insulating polypropylene (PP) into the PM6:Y6 bulk heterojunction (BHJ) active layer.
• Fabrication and characterization of thick-film organic solar cells (OSCs).
• Analysis of charge transport properties and trap state density.

Main Results:

• The addition of PP created an insulating matrix, enhancing molecular interactions and isolating charge transport.
• PP-blended devices showed reduced trap state density and improved charge transport.
• A thick-film device (around 300 nm) with PM6:Y6:PP achieved a power conversion efficiency (PCE) of 15.5%, exceeding the optimal thin-film device's efficiency.

Conclusions:

• Insulating polymers like PP offer an effective strategy for developing high-efficiency thick-film OSCs.
• This approach addresses key challenges for roll-to-roll printing and commercial production of organic solar cells.
• The study provides valuable insights into optimizing BHJ morphology for improved device performance.