Trapping and recombination phenomena in different conformations of irradiated P(VDF/TrFE) copolymer

In this work we show that radiation induced localized levels (trapping effects) and conductivity (RIC) phenomena in poly(vinylidene fluoride)-trifluoroethylene P(VDF-TrFE) copolymer samples depends on the molecular conformation. It was observed that at room temperature, under which P(VDF-TrFE) is ferroelectric and possesses a trans-planar conformation, recombination of charge carriers is negligible. Above the Curie temperature (TGTG' conformation), the RIC is three orders of magnitude higher, and recombination becomes an important process as the trapping time is considerably reduced. The experimental results were analysed using a modified multiple-trapping model usually applied to disordered materials. Important charge transport parameters were determined for the P(VDF-TrFE) copolymer for both, its ferro- and paraelectric phases.