Diazonium salt treated single-walled carbon nanotube thin films with high piezoresistive sensitivity

•A simple processing method developed for making SWCNT thin film strain sensors with significantly improved sensitivity.•Diazonium salt induced crosslinkage identified as the mechanism for the enhanced load transfer and gauge sensitivity.•The crosslinkage mechanism evidenced by a wisely designed electrical-mechanical-Raman spectroscopy coupled test method. Due to a lack of efficient load transfer, the Single-Walled Carbon Nanotube (SWCNT) thin film based piezoresisitve sensor typically has a low sensitivity. In this study, a simple method that invovles diazonium salt treament of a pristine SWCNT thin film was developed to enhance the load transfer efficiency of SWCNTs. As compared to the pristine thin film sensor, the gauge factor of the diazonium salt treated SWCNT thin films exhibited a ∼264% increase. Spectroscopy, microscopy, and in particular, the coupled mechanical-stretching and Raman scattering characterizations were performed to understand the diazonium salt treatment induced piezoresistivity enhancement of SWCNT thin films.