A Handwriting Method for Low-Cost Gas Sensors.

In this study, we report on an automated method based on a handwritten technique for the fabrication of low-cost gas sensors based on carbon nanotube (CNT) networks. Taking advantage of the inherent low-cost, flexible, and uncomplicated characteristics of pen-based techniques and combining them with an automated robotic system allows for high-resolution patterns, high reproducibility, and relatively high throughput considering the limitations of parallel processing. To showcase this, gas sensors capable of sensing NH3, CO2, CO, and ethanol, as well as temperature and relative humidity, are fabricated and characterized displaying competitive performance in relation to previously reported devices. The presented process is compatible with a variety of solutions and inks and, as such, allows for an easy integration into existing printing and coating frameworks with the greatest advantage being the ease of creating prototypes because of the nonstringent material requirements.