Calixarene-functionalized single-walled carbon nanotubes for sensitive detection of volatile amines

Abstract

Here we report a calixarene functionalized SWCNT hybrid for sensitive detection of volatile amines at room temperature. The hybrid formation was done through noncovalent functionalization of SWCNTs with calixarene using solvent casting technique, and the functionalization was confirmed through structural (SEM and TEM), spectroscopic (Raman spectroscopy) and electrical (ID − VD and ID − VG) characterizations. The results revealed a sensitive detection for all test analytes down to 1 ppm concentrations with a sensor sensitivity of 4.1%/ppm, 7.4%/ppm and 5.71%/ppm of NH3, TMA and DMA (commonly known as total volatile bases or TVBs), respectively. The limit of detection (LOD) of the hybrid was also found to be ∼0.6 ppm, ∼0.3 ppm and ∼0.4 ppm for NH3, TMA and DMA respectively. Further, the field effect transistor analyses indicated that the sensing mechanism of the SWCNT-calixarene hybrid is dominated by the electrostatic gating effect. The sensing capability of the hybrid at low analyte concentration and availability of wide variety of calixarene opens up the possibilities of development of only calixarene based SWCNT-calixarene sensor arrays for the realization of electronic nose application.