Determining the Occurrence of Electroluminescence in Polymeric Materials with respect to the Applied Alternating Electrical Stress

The emission of low level of light known as the electroluminescence (EL) has been used extensively to study charge injection and recombination mechanisms at the metal-polymer interface. This phenomenon has also been used as a probe to study early electrical ageing in high voltage cable insulation system since it can be associated with the energy dissipation of mobile and trapped charges in the molecules of the dielectric medium. Nowadays many works have been undertaken in order to understand the nature of EL in polymeric materials and its relationship with electrical ageing. This paper attempts to lay down the basic theory of the mechanism accountable for the phenomenon and relate it with some experimental observations made on typical polymers; namely low-density polyethylene (LDPE) and polyethylene naphthalate (PEN).