The Measurements Of Thermally Stimulated Current And Electroluminescence Of PET Films

Polyethylene terephthalate (PET) is a very common material and has a goodelectrical insulating properties. When it has been used under the electrical stressfor a long time, its peoperties show signs of performation degradation, while thedeterioration and degradation is irreversible current, ultimately lead to aging andeven breakdown.Electroluminescence (EL) is a phenomena that the electric energy isconverted to light energy, the light-emitting process includes excitation, energytransmission and recombination. It’s an effective method to research the chargeinjection and transport in polymer, in addition, it is an important means ofmeasuring polymer insulation aging. Thermally stimulated current (TSC) is oneof the thermal stimulation method, this test method is relatively simple, throughthe analysis of the TSC spectra, we could receive the parameters of material,such as the activation energy H and relaxation time τ. Here, we use twomeasurement to test PET film, then we could receive more informations, it issignificance for understanding the structure and performance of PET.The design of TSC equipment could be divided into three parts, thetemperature control system, the current measurement system and data acquisitionsystem respectively. the improvement is base on the electroluminescenceequipment, finally we have achieve the function of thermally stimulated currentmeasuring, and test the veracity of temperature and current data acquisitiona,prove the reliability of the measurement system.In this paper, The EL intensity and the spectrum of the of the PET filmsunder the different temperature (77K,296K,353K) is tested by home-made ELequipment. experiment shows that the temperature has little effect on PETproperties, the trap of PET mainly distributed in the2.06eV~2.47eV,2.75eV ~3.53eV. Test PET film by TSC measurement, then we could recieve TSC spectraand calculate its trap level by the full curve drawn method, the result show thatthe trap distribute at0.25eV. In the TSC spectra, the current peak is24.72pA,which corresponding temperature is371K, which shows that in this positiondistribute the maximum trap density.