Investigation of neural recording and stimulation capability of doped graphene-based nanomaterials

Neural electrodes serve as the interface material for interaction of electrical circuits with neural cells in neural stimulation and recording applications. In this study, it was aimed to investigate the effect of doping of graphene-based materials (GBM) on the recording and excitation performance of electrochemically interacted composite neural electrodes. For this purpose, we have utilized oxidation-reduction and electrochemical exfoliation methods to synthesize graphene oxide; pristine, nitrogen-doped and phosphorus-doped reduced graphene oxide and electrochemically exfoliated graphene materials. Samples of interest have characterized by their doping level, oxygen ratio, particle size, number of layers, defect density and exfoliation homogeneity with the help of energy dispersive X-ray analysis (EDX), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), X-ray diffraction analysis (XRD), Fourier-transform infrared spectroscopy (FT-IR) and Raman spectroscopy analysis. Measurements of the electrochemical properties was carried out with composite electrodes prepared with Polyvinylidene fluoride (PVDF) insulating polymer and GBM. Electrochemical analyzes of samples were interpreted with their physical-chemical characteristics and it was observed that the heteroatom doping in the C/O ratios of the GBM samples synthesized within the scope of the thesis did not exhibit a significant difference in the electrochemical measurements but the edge functionalization density formed by the oxygenated groups was effective on the electrochemical properties. Keywords: Graphene, graphene doping, electrochemical characterization, graphene characterization, neural electrode