(355c) Single Walled Carbon Nanotubes Based Ultra-Sensitive Resistor-Type Gas Sensors

Following facile synthetic procedures (electrospinning and membrane filtration), two single walled carbon nanotubes (SWNTs) based sensory materials have been prepared and applied for resistor-type gas detection. Both SWNTs based sensors have been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and UV-Vis. Specifically, incorporation of SWNTs into PPy nanocomposites by electrospinning generates a novel SWNTs composite nanofibers and a synergistic effect between SWNTs and PPy, resulting in an improved NH₃ detection limit as low as 36 ppb. Another SWNTs based sensor has been developed by the noncovalently immobilization of meso-tritolylcorrole (TTC) on SWNT networks through membrane filtration. This SWNT hybrid material possesses a donor-acceptor heterojunction through the π-π stacking, which facilitates exciton dissociation and thus greatly enhances the sensitivity towards NO₂ detection. Our experimental results show great potential of novel SWNTs based sensory materials in gas detection.