Electroluminescence in Polyethylene Terephthalate (PET). II. AC Voltage

Electroluminescence in polyethylene terephthalate (PET) was observed under AC voltages. The electroluminescence was found to be controlled by the injection of electrons from the Al electrode, together with the space charge accumulation. The occurrence of the injection and accumulation of electrons was demonstrated by thermally-stimulated current analysis. The significant modification of the internal field by the space charge resulted in an asymmetrical waveform of the electroluminescence in each half-cycle of the AC voltage.