Structural, optical, and electrical properties of multi-walled carbon nanotubes/polyaniline/Fe3O4 ternary nanocomposites thin film

摘要

Multi-walled carbon nanotubes/polyaniline/magnetite (MWCNTs/PANI/Fe3O4) ternary nanocomposites were synthesized. The ternary nanocomposites were synthesized through two main steps, namely; (i) polymerization of aniline in the presence of a carboxyl functionalized multi-walled carbon nanotubes to form binary MWCNTs/PANI. (ii) Co-precipitation of magnetite on the surface of MWCNTs/PANI binary composites to prepare MWCNTs/PANI/Fe3O4 ternary composites. MWCNTs/PANI/Fe3O4 ternary composite thin films were also fabricated via thermal evaporation technique in a vacuum at 1 x 10(-4) Pa. The characterization of the prepared ternary nanocomposites either powder or thin films were described by numerous techniques including FT-IR, TGA, TEM, XRD. The magnetic properties were investigated by the vibrating sample magnetometer (VSM). XRD showed the polycrystalline nature of a monoclinic crystal system with space group P2(1)/c of ternary nano composites powder and showed nanostructure of thin films as well. Optical properties (transmittance and reflectance) of the thin films with 300 nm thickness in the wavelength range of 300-850 nm were studied. The optical complex dielectric constant, optical conductivity, and optical energy band gaps E-g were calculated. The optical absorption data indicated that MWCNTs/PANI/Fe3O4 thin films have mainly both indirect and direct energy band gaps allowed transitions in the energy range of 2.90-3.41 EV. The dark current-voltage characteristics of the MWCNTs/PANI/ Fe3O4 thin films were non-linear and showed rectification behavior. The Rectification ratio (RR) of the forward and reverse currents at the same voltages (V = +/- 3 V) was found to be 5 at room temperature.