Tough-interface-enabled stretchable electronics using non-stretchable polymer semiconductors and conductors.

Area of Science:

• Materials Science
• Polymer Science
• Soft Electronics

Background:

• Semiconducting polymer thin films are crucial for soft electronics, but their brittleness limits applications.
• Existing methods like molecular design and nanoconfinement improve mechanical properties but have limitations.
• High-mobility polymers fracture easily under small strains, hindering their use in flexible devices.

Purpose of the Study:

• To investigate engineering interfacial properties to delay microcrack formation in semiconducting polymer films.
• To develop a universal strategy for enhancing the mechanical robustness of thin films through interface modification.
• To improve the crack-onset strain and cyclic durability of semiconducting polymers for advanced electronics.

Main Methods:

• Developed a universal design strategy involving a dissipative interfacial polymer layer with dynamic non-covalent crosslinks.
• Covalently bonded the interfacial layer between semiconducting thin films and substrates.
• Tested the crack-onset strain, interfacial toughness, delamination suppression, and cyclic durability of the modified films.

Main Results:

• Achieved a significant delay in microcrack formation, increasing crack-onset strain from 30% to 110%.
• Demonstrated high interfacial toughness, suppressed delamination, and delocalized strain effectively.
• Maintained bonding and exceptional cyclic durability despite large strain mismatches and reduced thermal expansion coefficient mismatch.

Conclusions:

• Engineering interfacial properties via a dissipative polymer layer is a highly effective strategy to enhance thin film robustness.
• This approach significantly improves the mechanical performance and durability of semiconducting polymers for soft electronics.
• The strategy is versatile and applicable to various thin films, including conducting polymers and metal films.