We report the fabrication of carbon nanotube (CNT) based gas sensors functionalized with different metallic nanoparticles (NPs) (Au, Pd, Ag) with exceptionally high responses towards four test gases (NH3, CO2, CO and ethanol). The CNT networks were fabricated through a low cost spray deposition process while the NPs were deposited by a thermal evaporation process. CNT based gas sensors functionalized with Au with a nominal thickness of 1.0 nm showed superior response towards NH3, CO and ethanol. The sensors' normalized responses reached 92%, 22% and 32% with concentrations of 100 ppm, 50 ppm and 100 ppm for NH3, CO and ethanol respectively. CNT based gas sensors functionalized with Pd with a nominal thickness of 1.5 nm showed the best performance with CO2. The normalized response reached 3%, 6%, 12% and 17% with concentrations of 500 ppm, 1000 ppm, 2500 ppm and 5000 ppm of CO2 respectively. We also investigated the morphological and optical changes that occur to the NPs upon thermal treatment. Functionalization of CNT films deposited on glass with Au and Ag showed surface plasmon resonance effects that are dependent on the nominal thickness of the functionalization layer.
Carbon nanotubes (CNTs) are one of the most interesting materials for printed electronics. The possibility to obtain CNT thin-films via solution-processing techniques has opened the way to lowcost applications such as, but not limited to, thin-film transistors (TFT). In this paper we present a spray deposition technique of CNT TFTs which can produce devices of exceptionally high yield, reproducibility as well as low variation in performance. Furthermore, the very fine control of the CNT deposition allows us better device engineering, thus increasing the integrability of CNT transistors into electronic systems. This represents a major step toward low-cost and large-scale production of CNT-based devices.
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