Chemiresistive sensor based on polythiophene-modified single-walled carbon nanotubes for detection of NO2

In the present investigation, a chemiresistive sensor based on conducting polythiophene-modified single-walled carbon nanotubes (SWNTs) for NO 2 detection has been reported. The SWNTs were aligned across 3 μm gap between two gold microelectrodes on Si / SiO 2 substrate. Alignment of SWNTs was carried out by using AC dielectrophoretic technique and it was confirmed by current–voltage (I–V) measurement. Aligned SWNTs were modified by conducting polythiophene using charge controlled potentiostatic deposition and it was confirmed by field-effect transistor (FET) and electrochemical measurements. Polythiophene-modified SWNT devices were used for the NO 2 detection in chemiresistive modality. This sensor exhibited very good linear response range from 10 ppb to 10 ppm.