Composites of ion-in-conjugation polysquaraine and SWCNTs for the detection of H₂S and NH₃ at ppb concentrations

Abstract Several different methods are established for the analysis of gases, including optical spectroscopy, photoacoustic spectroscopy as well colorimetric and resistive sensing, measurements systems either too complex or have limited sensitivity. In particular, when goal is to apply a large number sensors in networks, it highly desirable devices that simple, low cost energy consumption, yet sensitive selective monitor analytes even traces. Herein, we propose new type sensor device based on composite single-wall carbon nanotubes an ion-in-conjugation polymer, poly(1,5-diaminonaphthalene-squaraine), capable detecting H 2 S NH 3 air at room temperature with theoretical concentration limit ∼1 ppb ∼7 ppb, respectively. Density functional theory calculations revealed atoms O polymer chain interact form hydrogen bonds, electron withdrawal from gas molecules by results change its electrical conductivity. To demonstrate feasibility nanocomposites show monitoring food safety good stability operation least months period time.