Elasticization Enables Strain-Tolerant Microstructure and Enhanced Performance in Stretchable Polymer Solar Cells

Area of Science:

• Materials Science
• Polymer Science
• Renewable Energy

Background:

• Advancing intrinsically stretchable photovoltaic films is key for wearable electronics.
• All-polymer solar cells (APSCs) offer a promising route, but their mechanical robustness under strain needs improvement.
• Understanding microstructural evolution during stretching is critical for designing stable, high-performance stretchable devices.

Purpose of the Study:

• To investigate the nanoscale morphological changes in stretchable all-polymer solar cells (APSCs) under strain.
• To elucidate the role of elastomer blending, specifically styrene-isoprene-styrene (SIS), in enhancing mechanical and electrical properties.
• To provide insights into elastomer selection and microstructure design for improved stretchable electronics.

Main Methods:

• Utilized a synchrotron-based in situ stretching X-ray scattering technique to observe real-time nanoscale morphological changes.
• Fabricated stretchable APSCs incorporating a styrene-isoprene-styrene (SIS) elastomer.
• Evaluated device efficiency, mechanical stability under various strain levels, and long-term cycling performance.

Main Results:

• Incorporation of SIS elastomer enhanced π-π stacking intensity parallel and perpendicular to the stretching direction.
• Achieved a record-high APSC efficiency exceeding 16%.
• Demonstrated exceptional mechanical stability, retaining over 80% efficiency at 60% strain and 81% after 1000 cycles at 40% strain. Power output remained stable up to 60% strain.

Conclusions:

• The study provides critical insights into the structure-property relationships in stretchable APSCs.
• SIS elastomer incorporation is beneficial for enhancing both mechanical integrity and photovoltaic performance.
• Findings guide future material selection and device engineering for robust, high-performance stretchable electronic applications.