Highly Selective Detection of Organophosphorus pesticide Methyl parathion on Ag-ZnO-SWCNTs based Field-Effect Transistors
Semiconducting single-walled carbon nanotubes (s-SWCNTs) have been used in electrical transducers for environmental and health monitoring due to their quasi ballistic electronic transport, efficient transconductance, high carrier mobility, high On/Off ratio, excellent mechanical properties etc. Herein, we have prepared a non-enzymatic pesticide sensor to selectively detect methyl parathion (MP, which is a restricted use pesticide by EPA) using silver-zinc oxide (Ag-ZnO) composite decorated s-SWCNTs based field-effect transistor (FET). Ag/ZnO/s-SWCNTs film is also characterized by field-emission scanning electron microscopy (FE-SEM), Energy-dispersive spectrometry (EDS), X-ray diffraction (XRD) spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, Ultraviolet visible (UV-Vis) spectroscopy, Raman spectroscopy and photoluminescence (PL) spectroscopy. The response of the Ag-ZnO/s-SWCNTs-FET was measured under ambient condition in the presence and absences of MP. Hydrolysis of MP is taken place due to the potent catalytic activity of Ag-ZnO, which led to changes in transistor conductance. Based on this, detection of different concentrations of MP was demonstrated by Ag-ZnO-s-SWCNTs-FET. The Ag-ZnO-s-SWCNTs/FET device showed a linear response from 1×10-16 M to 1×10-4 M MP with a limit of detection (LOD) of 0.45×10-16 M in 100 mM PBS. In addition, Ag-ZnO/s-SWCNT-FET exhibited acceptable reproducibility and repeatability when employed for MP detection. Moreover, the proposed MP sensor was highly stable in ambient condition. Finally, detection of MP is demonstrated in soil and rice samples with good recovery.