Tin Oxide Electron Transport Layers for Air-/Solution-Processed Conventional Organic Solar Cells

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Organic solar cells (OSCs) are nearing commercialization, with interlayers significantly impacting device efficiency and stability.
• Electron transport layers (ETLs) are critical components in optimizing OSC performance.

Purpose of the Study:

• To evaluate tin oxide nanoparticles (SnO₂ NPs) as an electron transport layer (ETL) in conventional organic solar cells (OSCs).
• To develop a processing method for SnO₂ NPs that is compatible with large-scale manufacturing techniques like slot-die coating.

Main Methods:

• A commercial SnO₂ NPs solution was mixed with ethanol (EtOH) as a co-solvent to enhance film formation.
• The optimized SnO₂ NPs ink was coated onto polymer:fullerene and nonfullerene organic photoactive layers.
• Photovoltaic performance was measured for devices with and without the SnO₂ NPs ETL.

Main Results:

• The addition of SnO₂ NPs as an ETL significantly enhanced photovoltaic performance across multiple organic solar cell systems.
• Devices utilizing SnO₂ NPs showed efficiency increases from 3.4% to 6.0% (PBDB-T:PC₆₁BM), 3.7% to 5.7% (PPDT2FBT:PC₆₁BM), and 3.7% to 7.1% (PTQ10:IDIC).
• Uniform SnO₂ NPs films with low photoactive layer degradation were achieved using optimized processing conditions.

Conclusions:

• SnO₂ nanoparticles are effective as an electron transport layer (ETL) in organic solar cells (OSCs), boosting device efficiency.
• The developed SnO₂ NPs ink is versatile and suitable for air-processed, all-slot-die-coated flexible devices, indicating potential for large-scale production.
• This research paves the way for more efficient and stable organic solar cells through advanced interlayer engineering.