(Invited) Fully-Printed Stretchable Electronic Devices and Circuits

Flexible electronics has generated great amount of interest due to its wide range of potential applications in flexible displays, wearable electronics and sensors, implantable biomedical devices, and many more. Despite significant amount of success and progress being made in the field, mechanical flexibility alone may not be sufficient for certain applications. For instance, in order to conformally wrap a surface with nonzero Gaussian curvature, stretchable electronic system is needed. In this talk, I will present our recent work on addressing the two major challenges faced by stretchable electronics - the development of intrinsically-stretchable electronic materials and the need for scalable fabrication processes. We have developed nanomaterials-based metal, semiconductor, and dielectric materials with superior electronic property, stretchability, and inter-layer adhesion. Such materials are formulated as electronic inks to allow highly uniform and scalable material patterning using a fully-printed process, allowing us to directly print high-performance thin-film transistors (TFTs) and logic circuits onto ultrathin elastomer substrates. Electrical and mechanical characterizations reveal that the TFTs and inverters can withstand biaxial strain of up to 125% for hundreds of cycles. The TFTs also exhibit respectable performance with field-effect mobility up to 10 cm2/Vs. This work represents a major step forward in moving the stretchable electronics research from proof-of-concept demonstrations toward practical applications in wearable devices or stretchable displays.