Supposition of graphene stacks to estimate the contact resistance and conductivity of nanocomposites

In this study, the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously reported. The contact resistance and nanocomposite conductivity are modeled by several influencing factors, including stack properties, interphase depth, tunneling size, and contact diameter. The developed model’s accuracy is verified through numerous experimental measurements. To further validate the models and establish correlations between parameters, the effects of all the variables on contact resistance and nanocomposite conductivity are analyzed. Notably, the contact resistance is primarily dependent on the polymer tunnel resistivity, contact area, and tunneling size. The dimensions of the graphene nanosheets significantly influence the conductivity, which ranges from 0 S/m to 90 S/m. An increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite’s conductivity. Furthermore, the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy.