Title :
Electroluminescence in insulating polymers in ac electric fields
Author :
Mizuno, T. ; Liu, Y.S. ; Shionoya, W. ; Yasuoka, K. ; Ishii, S. ; Miyata, H. ; Yokoyama, A.
Author_Institution :
Dept. of Electr. & Electron. Eng., Tokyo Inst. of Technol., Japan
fDate :
8/1/1997 12:00:00 AM
Abstract :
EL (electroluminescence) in several polymeric materials was investigated in the electric field range <90 kV/mm. We used polymeric films with semi-transparent gold electrodes: low density polyethylene, polypropylene, polytetrafluoroethylene and polyvinylchloride. The EL characteristics were very low EL inception fields (2 to 20 kV/mm) which strongly depend on the material and very low energy photon emission (mainly in the red region of 1.6 to 1.8 eV). These results reveal that EL emission occurs predominantly in the metal-polymer interface region rather than in the bulk of the polymer at the applied field. We present a model of EL emission in the metal-polymer interface region to explain our results qualitatively. In this model, the mechanism of EL emission is the radiative recombination of the electrons and holes trapped at the surface states of the polymer, which causes photon emission in the red region. The EL inception field and EL intensity depend on the density of the surface states of the polymers
Keywords :
electroluminescence; electron-hole recombination; metal-insulator boundaries; organic insulating materials; polyethylene insulation; polymer films; surface states; 1.6 to 1.8 eV; Au; EL inception fields; ac electric fields; electroluminescence; electron hole recombination; insulating polymers; low density polyethylene; low energy photon emission; metal-polymer interface region; model; polymeric films; polypropylene; polytetrafluoroethylene; polyvinylchloride; radiative recombination; red region; semi-transparent Au electrodes; surface state density; Dielectrics and electrical insulation; Electric fields; Electrodes; Electroluminescence; Gold; Plastic films; Plastic insulation; Polyethylene; Polymer films; Radiative recombination;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
