Polymer-Based Thermally Stable Chemiresistive Sensor for Real-Time Monitoring of NO₂ Gas Emission

Abstract

We present a thermally stable, mechanically compliant, and sensitive polymer-based NO2 gas sensor design. Interconnected nanoscale morphology driven from spinodal decomposition between conjugated polymers tethered with polar side chains and thermally stable matrix polymers offers judicious design of NO2-sensitive and thermally tolerant thin films. The resulting chemiresitive sensors exhibit stable NO2 sensing even at 170 °C over 6 h. Controlling the density of polar side chains along conjugated polymer backbone enables optimal design for coupling high NO2 sensitivity, selectivity, and thermal stability of polymer sensors. Lastly, thermally stable films are used to implement chemiresistive sensors onto flexible and heat-resistant substrates and demonstrate a reliable gas sensing response even after 500 bending cycles at 170 °C. Such unprecedented sensor performance as well as environmental stability are promising for real-time monitoring of gas emission from vehicles and industrial chemical processes.

Conjugated polymers with near-infrared (NIR) optical absorption: structural design considerations and applications in organic electronics

“…Recently, there have been developments in the fabrication of polymer composite materials for thermally robust OFETs and gas sensors where temperatures were set to 220 °C while maintaining hole mobilities >2.0 cm 2 V −1 s −1 . 299,300 These CP and non-conjugated polymer composite materials enable operation at extreme temperatures, which opens new opportunities for organic electronics where previously only inorganics offered viable technologies. This research area could be expanded to include NIR-CPs in OPV, where thermal stability test are often <100 °C, and ECDs where device operational stability at temperatures of 180 °C has been demonstrated.…”

Robust Chemiresistive Behavior in Conductive Polymer/MOF Composites

“…We select the ProDOT-BTD cP for its reversible redox-activity, low onset oxidation voltage, charge capacity, electrical conductivity to enhance the device response in presence of the analyte. [32,33] Particularly, the cP is designed to serve as a secondary NO 2 -affine component endowed by its polar sidechains, [34][35][36][37] as well as a binding matrix to physically unify cMOF crystallites and improve electrical communication throughout the bulk (Figure 1c,d). We then select two classes of cMOFs based on HHTP and HITP ligands (Figure 1a), which typically exhibit irreversible gas sensing behaviors in their pristine form.…”

Recent Progress in Gas Sensors Based on P3HT Polymer Field-Effect Transistors

“…Conversely, in solar cells, where charge transport should be perpendicular to the substrate, face-on and end-on structures are preferable. Thus, the crystallization and orientation of P3HT can be finely adjusted in line with application prerequisites, thereby enhancing the resulting performance [27][28][29][30].…”