Electronics and circuits fully comprised of rubbery electronic materials thus having mechanical softness and stretchability at both microscopic (material) and macroscopic (structural) levels are critical for many technically challenging yet important applications such as electronics-organ symbiosis, humanoids, and wearable and implantable bioelectronics. To create rubbery electronics and circuits, rubbery semiconductor is an indispensable material. Meanwhile, it is critically important that the rubbery semiconductor has high carrier mobility and can be scalably manufactured to achieve high performance integrated electronics and systems to meet the aforementioned applications. Although there have been a few recent reports on creating stretchable semiconductors, the material development is still nascent. The reported materials are primarily based on solution spin coating, solution-shearing, or drop casting of semiconducting composites. The devices fabricated using those materials and approaches either have relatively low carrier mobility or lack device uniformity for integrated electronics. Therefore, to fully realize the practical usage of rubbery electronics and circuits, a technology gap in scalable manufacturing of high mobility, stretchable semiconductors must be bridged.  

Here, we report the facile and scalable manufacturing of high performance stretchable semiconducting nanofilms and the fully rubbery transistors, integrated electronics and functional devices. Specifically, the rubbery semiconducting nanofilm is scalably manufactured into a freestanding format based on air/water interfacial assembly method, which particularly leads to favorable molecular packing of P3HT molecules and the resulted high carrier mobility. The binary phased rubbery composite semiconducting nanofilm advantageously offers mechanical stretchability. The yielded composite nanofilm has distinct advantages: i) high charge carrier mobility; ii) excellent mechanical stretchability by 50% without significant decay in carrier mobility; and iii) simple, scalable, repeatable, and low-cost manufacturing. Rubbery transistors and their arrays made fully out of rubbery conductor, semiconductor, and dielectric have been developed. The demonstrated rubbery electronics, from the fundamental building block of a transistors to logic gates, to active matrix multiplexing electronics, and to functional E-skins, show the potentials of rubbery electronics and circuits, whose mechanical softness and stretchability stem from the intrinsic properties of the material used. The rubbery transistors can be stretched up to 50% with a reasonable decrease in their mobility. In addition, fully rubbery logic gates have been realized and their logical functions were maintained even under 50% applied strain. Furthermore, an elastic smart skin with a 5×5 rubbery transistor array based active matrix with multiplexed spatiotemporal mapping capability was developed. Finally, a multi-functional rubbery electronic skin (E-skin) was developed and implemented on a robotic hand to illustrate its function as a medical diagnostic and therapeutic device. The air/water interfacial assembled semiconducting nanofilm and rubbery electronic devices described here suggest a feasible pathway towards rubbery electronics and integrated systems and their broad emerging applications.


Air/water Interfacial Assembled Rubbery Semiconducting Nanofilm for Fully Rubbery Integrated Electronics

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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