A method for the calculation the activation energies of thermally stimulated depolarization current peaks: Application in polyvinylidene fluoride/graphene nanocomposites

Abstract

A simple method is presented for the calculation of the activation energies of first order peaks of Thermally Stimulated Depolarization Current (TSDC). Three equations are derived, which relate the activation energy of the relaxation process, to three characteristic temperatures of the TSDC thermographs, which correspond to the peak temperature TM, and the half of the peak current temperatures T1, T2 (T1<T2). Each equation gives an expression of the activation energy as a function of two out of the three characteristic temperatures of the TSDC peak, assuming typical values of activation energy in the range 0.2–2.0 eV. The proposed equations were compared with other methods based on the same characteristic temperatures, in pristine PVDF and PVDF with 1wt% graphene samples at a temperature range where the MWS relaxation takes place. In PVDF-graphene samples, the MWS peak was found to consist of two overlapping mechanisms.