Webinar: Space Charge Characteristics in Nanodielectrics

Nanodielectrics have attracted significant attention in last two decades due to their potential applications in a wide range of power devices as “super insulation”. Relying on the strong interaction between nanoparticles and polymer matrix at the interface, the nanocomposites can be tailored to achieve desired properties, including electrical, thermal and mechanical etc. In terms of the enhanced electrical performance of nanocomposites, there are widely reported improvements in electrical breakdown strength, corona/discharge resistance, suppression of space charge and varied dielectric permittivity. Unfortunately, the detailed mechanisms leading to these improvements are not known yet. In addition, there are also inconsistent/conflict electrical performance results presented in literature. It has been realized that the quality of samples is influenced by so many factors. If those factors are not strictly controlled during sample preparation, discrepancy in the observed results should not be surprised. In this presentation, the focus is placed on charge dynamics in nanocomposites and the influential factors. By combining the surface potential and space charge measurements, it is possible to reveal trapped charge in nanocomposite adjacent to nanocomposite sample surface. This finding allows us to understand the mechanism of charge suppression in nanocomposites using deep traps introduced in the nanocomposites. Furthermore, by measuring space charge in the two layered nanocomposite films with different concentrations of nanoparticles it explains why the charge suppression can only occur in those nanocomposites with a low concentration of nanoparticles. Initial simulation based on the bipolar charge transport model is used to validate the proposed charge trapping/transport processes in nanocomposites.