Flexibility characteristics of a polyethylene terephthalate chemiresistor coated with a nanoparticle thin film assembly

Abstract

Polyethylene terephthalate (PET) functions as a flexible substrate for the fabrication of functional devices by low-cost and scalable roll-to-roll manufacturing. Exploration of this attribute for chemical sensors requires understanding of the flexibility characteristics in correlation with the sensing properties in terms of a combination of device strain and molecular interactions in different chemical environments. This report describes new findings of an investigation of the response characteristics of PET chemiresistor sensors coated with a thin film assembly of gold nanoparticles in response to different device strains and adsorption of volatile organic compounds. The work demonstrates that the sensor response characteristics can be tuned by a combination of flexible device strain parameters. A significant finding is that the contribution to the changes in the sensing signals and sensitivities depends on not only the molecular nature of species being detected, but also a combination of the interparticle spatial, dielectric medium, and device strain properties. This combination is also associated with the orientation of the microelectrode patterns with respect to the device strain direction. These findings have an important implication for the design of nanoparticle-coupled flexible chemical sensors for effective detection of chemical or biological species in different sensing environments.