Electrical conduction of metallized BOPP films based on revised Poole-Frenkel effect

In high energy density capacitors, the electrical conduction in the dielectric may result in the leakage and the reduction of the energy efficiency. This paper investigates the electrical conduction mechanism of metallized biaxially oriented polypropylene (BOPP) film based on a revised Poole-Frenkel (PF) effect and field-enhanced carrier mobility. The field-enhanced carrier mobility which is not taken into account in traditional PF effect is investigated in the revised PF effect based on the carrier hopping mechanism. Moreover, the coefficient of the PF effect (βPF) which stands for the variation of the barrier height is discussed. Experiments are performed to measure the electrical conductivity of the BOPP film under different electric fields. Influencing factors such as metallized electrodes, the interlayer pressure in the winding, and the crystallinity may decrease the conductivity. With a fitted jump distance of 0.6 nm, the calculated conductivities based on the revised PF effect do match well with experimental results.