Highly Robust and Strain-Resilient Thin Film Conductors Featuring Brittle Materials

Stretchable conductors with stable electrical conductivityundervarious deformations are essential for wearable electronics, softrobots, and biointegrated devices. However, brittle film-based conductorson elastomeric substrates often suffer from unexpected electricaldisconnection due to the obvious mechanical incompatibility betweenstiff films and soft substrates. We proposed a novel out-of-planecrack control strategy to achieve the strain-insensitive electricalperformance of thin-film-based conductors, featuring conductive brittlematerials, including nanocrystalline metals (Cu, Ag, Mo) and transparentoxides (ITO). Our metal film-based conductors exhibit an ultrahighinitial conductivity (1.3 x 10(5) S cm(-1)) and negligible resistance change (R/R (0) = 1.5) over wide strain range from 0 to 130%, enabledby film-induced substrate cracking and liquid metal-induced electricalself-repairing. They could function well under multimodal deformations(stretching, bending, and twisting) and severe mechanical damage (cuttingand puncturing). We demonstrated the strain-resilient electrical functionalityof metal film-based conductors in a flexible light-emitting diodedisplay that shows high mechanical compliance.