High Electric Field and Energetic Processes in Poly(ethylene naphthalate)

Poly(ethylene naphthalate) is a semi-crystalline polymeric material having high field withstanding and strong luminescence properties owing to its aromatic structure. Because of these two features it is the insulating polymer having strongest electroluminescence-EL yield investigated so far. EL is detected in an electric field regime where strong non-linear conduction properties have been identified. The light excitation mechanism, though not completely elucidated could be charge recombination with a contribution from impact excitation. It is believed that copious space charges effects are at play in the field regime when EL is detected. The EL spectrum shape evolves with field and some of the bands were ascribed to electrical ageing of the material. All of these features make of PEN a fascinating model material for investigating fundamental processes at play under high fields in insulating polymers.