Flammable carbon nanotube transistors on a nitrocellulose paper substrate for transient electronics

Transient electronics represent an emerging class of technology comprising materials that can vanish in a controlled manner in response to stimuli. In contrast to conventional electronic devices that are designed to operate over the longest possible period, transient electronics are defined by operation typically over a short and well-defined period; when no longer needed, transient electronics undergo self-deconstruction and disappear completely. In this work, we demonstrate the fabrication of thermally triggered transient electronic devices based on a paper substrate, specifically, a nitrocellulose paper. Nitrocellulose paper is frequently used in acts of magic because it consists of highly flammable components that are formed by nitratil^g cellulose by exposure to nitric acid. Therefore, a complete and rapid destruction of electronic devices fabricated on nitrocellulose paper is possible without producing any residue （i.e., ash）. The transience rates can be modified by controlling radio frequency signal-induced voltages that are applied to a silver （Ag） resistive heater, which is stamped on the backside of the nitrocellulose paper. The Ag resistive heater was prepared by a simple, low-cost stamping fabrication, which requires no harsh chemicals or complex thermal treatments. For the electronics on the nitrocellulose paper substrate, we employed semiconducting carbon nanotube （CNT） network channels in the transistor for superior electrical and mechanical properties.

Morphology-and ion size-induced actuation of carbon nanotube architectures

Future adaptive applications require lightweight and stiff materials with high active strain but low energy consumption.A suitable combination of these properties is offered by carbon nanotubebased actuators.Papers made of carbon nanotubes(CNTs)are charged within an electrolyte,which results in an electrical field forming a double-layer of ions at their surfaces and a deflection of the papers can be detected.Until now,there is no generally accepted theory for the actuation mechanism.This study focuses on the actuation mechanism of CNT papers,which represent architectures of randomly oriented CNTs.The samples are tested electrochemically in an in-plane set-up to detect the free strain.The elastic modulus of the CNT papers is analyzed in a tensile test facility.The influence of various ion sizes of water-based electrolytes is investigated.During the tests,four parameters that have a significant influence on the mechanical performance of CNT papers were identified:the test conditions,the electrical charging,the microstructure and the ion size.All of these influencing factors point to the mechanically weak inter-tube linking at which the actuation seems to take place.Quadratic voltage-strain correlation suggests a combination of electrostatic and volumetric effects as the possible reason for CNT paper actuation.