Influence of frequency, electrode material and superimposed dc on ac electroluminescence in polymer films

This paper summarizes new results on the influence of some experimental parameters on ac electroluminescence (EL) of polymers used as insulating materials in electrical engineering. Electroluminescence under a uniform ac field is investigated in low density polyethylene (PE) and polyethylene naphthalate (PEN) films with semi-transparent electrodes on both sides. Particular emphasis is given to polyethylene. The dependence of EL on the voltage frequency is investigated in the range of 10(-2) Hz to to 10(+2) Hz with the help of phase-resolved measurements. The influence of the electrode/polymer contact is investigated by changing the electrode material (gold, silver, and calcium). The effect of a superimposed dc bias on the ac voltage is also reported.