We have designed and developed surface acoustic waves (SAWs) sensors coated by either single-wall carbon nanotubes (SWCNTs) or multi-wall carbon nanotubes (MWCNTs) for chemical detection of volatile organic compounds (VOCs), at room temperature. Upon individual exposure to ethanol, ethylacetate and toluene in nitrogen, the resonance frequency of the SAW 433.92 MHz oscillating sensor exhibits high downshift of 720 (150), 670 (160), 450 (110) kHz, respectively, for SWCNTs (MWCNTs) films dispersed into solvent of ethanol, at room temperature. Higher sensitivity than that of organic layer-coated SAW sensors can be achieved, at room temperature. The selectivity to VOCs under test can be controlled by the type of organic solvent used to disperse the carbon nanotubes as sensing materials onto SAW sensors.
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