Space charge in nanodielectrics and its impact on electrical performance

Nanodielectrics have been actively investigated in last two decades as they have shown some improved dielectric properties that are important for high voltage insulation applications. One of these improvements is the reduction in space charge when the nanodielectrics are subjected to dc electric fields. The formation of deep trap after introducing nanoparticles in the material has been widely reported. However, the mechanisms that are responsible for the charge suppression are not detailed. More importantly, the effect of charge suppression is strongly dependent on the amount of nanoparticles, i.e. loading concentration. In the present paper, a schematic model has been proposed based on deep trap concept. A tunneling process has been introduced when the trapping sites become closer which is the case for high nanofillers concentration. Based on the new model, charge formation and dynamics in nanodielectrics with different loading concentrations can be estimated and electrical performance anticipated. A range of factors that can influence charge trapping/detrapping have been discussed.