A General Elastomeric Agent to Addressing Embrittlement in High-Efficiency Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Organic solar cells (OSCs) require mechanical resilience for wearable applications.
• Current OSCs suffer from film embrittlement due to acceptor materials acting as stress concentrators.
• A universal method for toughening OSCs is needed.

Purpose of the Study:

• To introduce a broadly applicable strategy for toughening OSCs.
• To enhance the mechanical resilience and maintain the photovoltaic efficiency of OSCs.
• To develop intrinsically stretchable OSCs.

Main Methods:

• Utilized SEEPS, an elastomeric agent with tailored miscibility with acceptors.
• Defined a toughening parameter η using dynamic mechanical analysis.
• Employed in situ grazing-incidence X-ray scattering to analyze material behavior under strain.

Main Results:

• SEEPS induced over an 11-fold increase in fracture strain by dissipating strain energy.
• The elastomeric agent preserved molecular packing and suppressed phase separation under strain.
• Stretchable OSCs retained four-fifths of their initial efficiency after 500 stretch-release cycles at 40% strain.
• Achieved over 16% power conversion efficiency in intrinsically stretchable OSCs.

Conclusions:

• The SEEPS-based strategy offers a general approach to toughen OSCs.
• This method enables the development of high-performance, mechanically robust, and stretchable organic solar cells.
• The findings provide insights for designing next-generation flexible and wearable photovoltaic devices.