Surface Electroluminescence Phenomena from Polymer under AC Voltage

Electroluminescence (EL) phenomena from polymers has been investigated under 50Hz ac electrical stress. Because the light emission is very week, so we employ a sensitive photon counting module (PCM) and put the sample into vacuum chamber to avoid the influence of gases or impurities absorbed on the surface of the sample. We use three kinds of materials such as PTFE, LDPE, and PP in this experiment. Their surface trap parameters are measured according to the theory of isothermal relaxation current (IRC). By that method we acquire the trap energy level and trap density of both electrons and holes distributing in the surface layer of each insulating polymer. We find that there is some relationship between the surface trap parameters of solid polymer insulating materials and their molecule structure, and surface trap has influence on light emission from polymer insulating material