Fully printed and flexible carbon nanotube transistors designed for environmental pressure sensing and aimed at smart tire applications

As the sensor infrastructure needed to facilitate the internet-of-things (IoT) rapidly expands, printed electronics have been identified as a key approach for providing low-cost, ubiquitous sensor networks. In this work, we demonstrate the use of a fully printed carbon nanotube thin-film transistor (CNT-TFT) for sensing environmental pressure over a large pressure range. The transconductance of the transistor was found to be directly and linearly correlated with environmental pressure with a sensitivity of 48.1 pS/PSI. We also demonstrate the capability of wirelessly transmitting the data measured by the pressure sensor from within an automobile tire using a simple Bluetooth module. Furthermore, we package the sensor, along with a material thickness sensor developed in previous work, for a fully printed smart tire sensor system capable of mapping tire pressure and tread depth differentials.