Effect of graphene loadings on electrical properties of polyaniline-polystyrene blend film

Due to the ultra-high aspect ratio and excellent electrical properties of graphene, graphene-based polymer composites have shown remarkable performance and have increased their application scope in the field of electronic devices. The solution cast method is used to prepare films of polyaniline (PANI)-polystyrene(PS) blends with different graphene loadings. The films are characterized by x-ray diffraction, Fourier transforms infrared (FT-IR) spectroscopy, Raman spectroscopy, UV–Vis spectroscopy, thermogravimetric analysis, and transmission electron microscopy (TEM). Room temperature electrical conductivity and Hall measurements are used to study the DC electrical conductivity and carrier mobility in these nanocomposite films. UV–Vis spectroscopy shows a decrease in optical band gap (2.53 eV) for graphene-based PANI-PS polymer nanocomposites compared to the PANI-PS (2.73 eV) blend. The nanocomposite films show percolative enhancement of electrical conductivity with graphene loadings. The percolation threshold of this composite is achieved at a very low filler concentration (0.19 wt %). The Hall coefficient changes its sign from p-type to n-type with the addition of graphene loadings, demonstrating modulation in the majority charge carrier in the semiconducting polymer composite. The polymer composite films show nearly two order enhancement in carrier mobility with the addition of graphene.