Effect of Electrode Material Type on Space Charge Characteristics in Polymers

Space charge usually occurs in polymers used in electrical equipment and electronics devices under operation, which will distort electric field distribution and accelerate the aging process. To investigate in the effect of different electrode materials on space charge injection process in polymers, five different types of metal materials: Ag, Au, Cu, Sn and Zn were sputtered on the surface of polymer as electrodes. The space charge dynamics of three different polymers: epoxy resin (EP), polyethylene (PE) and polyimide (PI) coated with different types of metal electrodes were measured using the pulsed electro-acoustic (PEA) method. The effect of metal electrode materials on space charge distribution of different polymers are analyzed. The injection barrier is found partly mainly related to the work function, but is also affected by other factors such as electron affinity.