Scalable Non-Halogenated Co-solvent System for Large-Area, Four-Layer Slot-Die-Coated Organic Photovoltaics

Area of Science:

• Materials Science
• Sustainable Energy
• Chemical Engineering

Background:

• Commercializing printed organic photovoltaics (OPVs) requires sustainable processing solvents, scalable manufacturing, and advanced photoactive materials.
• Current high-performance OPV research often relies on hazardous halogenated solvents and non-scalable fabrication methods.
• Developing eco-friendly alternatives is crucial for the widespread adoption of OPV technology.

Purpose of the Study:

• To demonstrate large-area slot-die manufactured OPV cells using environmentally friendly, halogen-free solvents and scalable materials.
• To optimize processing conditions for high-quality thin-film fabrication of all four OPV layers via slot-die coating.
• To evaluate the performance of these eco-friendly OPVs under standard solar and indoor lighting conditions.

Main Methods:

• Employed slot-die coating in air for all four layers: electron transport layer (SnO2), cathode interlayer (PDIN-H), bulk-heterojunction (BHJ, PTQ-10:BTP-4F-12), and hole transport layer (PEDOT:PSS).
• Utilized a non-halogenated co-solvent mixture of toluene and 2-methyl tetrahydrofuran for optimal processing of the PTQ10:BTP-4F-12 BHJ layer.
• Addressed wettability challenges for PEDOT:PSS slot-die coating by employing a surface treatment method.

Main Results:

• Achieved high power conversion efficiencies (PCEs) of 12.1% under 1 Sun (100 mW/cm2) and 17.8% under indoor LED lighting (580 μW/cm2) for unencapsulated champion cells.
• Successfully fabricated all-layer slot-die coated OPVs with a PCE of 9.55%.
• Demonstrated the feasibility of using eco-friendly solvents and scalable manufacturing techniques for high-performance OPVs.

Conclusions:

• The study successfully developed a scalable and sustainable manufacturing process for OPVs using halogen-free solvents and slot-die coating.
• The fabricated OPVs exhibit promising performance, indicating the potential for commercialization.
• This work paves the way for greener and more cost-effective production of organic solar cells.