Stretchable Carbon Nanotube Thin-Film Transistor Arrays Realized by a Universal Transferable-Band-Aid Method

Abstract

Stretchable electronics offer new possibilities for humans and artificial intelligent robots, in which stretchable transistors are the core components. Either geometric engineering or intrinsic material integration has its own limitations for realizing high-performance stretchable transistors. In this work, by combining the advantages of both approaches, we propose a novel transferable-Band-Aid method to realize stretchable carbon nanotube (CNT) thin-film transistor (TFT) arrays with high electrical performance and stretchability simultaneously. This method uses polyimide (PI) tapes to transfer devices to elastomer substrates. The mobility and ON/OFF-current ratio of the stretchable CNT-TFTs reach 24 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> / <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\cdot \text{s}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.1\times10$ </tex-math></inline-formula> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> , respectively. After stretched by 50% and 100% for 2000 cycles, the device performance is maintained on both polydimethylsiloxane and Eco-flex substrates. Neither obvious degradation on electrical properties nor displacement between the PI and the elastomer is observed during the stretching. The mechanical performance of the stretchable devices has also been verified and analyzed by simulation using ANSYS. Young’s modulus ratio between the stiff island and the elastomer substrate influences stretchability and stress distribution of the devices. The simulation result provides a guideline for realizing highly robust stretchable devices. The Band-Aid structure could generally be stuck to most elastomer substrates, providing a new solution to convert flexible devices into stretchable devices universally. The demonstrations of the design exhibit its excellent transferability, conformal capability, and versatility, showing its application potentials in wearable devices, biological-human interfaces and Internet of Things.