Field emission (FE) currents were measured for prinstine single-walled carbon nanotubes (SWCNTs), and after encapsulation of electron withdrawing and donating molecule, i.e., 7,7,8,8-tetracyano-p-quinodimethane (TCNQ) and tetrathiafulvalene (TTF). X-ray photoelectron spectrometer, infrared, and Raman spectrometer were used to confirm encapsulation. TCNQ-doped SWCNTs (TCNQ-SWCNT) enhanced, and TTF-doped SWCNTs (TTF-SWCNT) decreased FE properties compared with pristine SWCNTs. The turn-on field of the pristine SWCNTs, TCNQ-SWCNT, and TTF-SWCNT were calculated to be 2.5, 2.3, and 3.2V∕μm, respectively, and the maximum currents were obtained, in turn, 180, 329, and 21μA∕cm2 at the electric field of 3.6V∕μm. To explain the FE properties, the work function of doped SWCNTs were calculated from Fowler-Nordheim equation, and also the resistivity of three samples was measured by four-point probe method and compared with each other.

The ZnO nanostructure layers have been widely investigated as electrodes for sensors due to their intrinsic advantages such as high active area and low cost. In this work, to enhance the detection properties of ZnO nanostructural electrodes, self-organized ZnO nanorod arrays were synthesized using the chemical bath deposition (CBD) method on FTO glasses and ZnO nanoparticles. The fabricated ZnO electrodes on the two different substrates were characterized by SEM, TEM, XRD, and XPS. Subsequently, the detection performance of ZnO nanorod electrodes was electrochemically measured in a 2,4,6-trinitrotoluene (2,4,6-TNT) solution by CV and EIS. The differences in current densities between the ZnO electrodes were determined by the width of the ZnO nanorods, resulting in a ∼45% higher detection efficiency with F-CBD (the ZnO nanorods on FTO) electrodes compared to S-CBD (the ZnO nanorods on ZnO nanoparticles) electrodes.