Linking traps to dielectric breakdown through charge dynamics for polymer nanocomposites

Abstract

Polymer nanocomposites can change the density and/or energy of traps, suppress the accumulation of space charges, and enhance dielectric breakdown strength. It is of interest to reveal the influencing mechanism of trap properties on the dielectric breakdown of polymer nanocomposites. Results of thermally stimulated depolarization current and surface potential decay were reviewed, showing that incorporating a small amount of nanoparticles into a polymer can increase the density and/or energy of deep traps. Then, the relation between traps and dc breakdown field of several polymer nanocomposites were analyzed. It was found that the increase in the density and energy of deep traps contributes to the improved dielectric breakdown performance. The modifications of traps by nanoparticles and surface treatments affect the charge dynamics in the bulk of polymer nanocomposites. Then, the accumulation of space charges, the distortion of electric field, and the energy gain of free carriers are regulated to improve the performance of dielectric breakdown.