Influence of the (E)-N-(4-diphenylamino)benzylidene)benzo[d] thiazol-2-imine on the dielectric properties of P3HT, PCBM and P3HT: PCBM system in a wide temperature and frequency range

We investigated the relaxation processes occurring in the sub-hertz frequency range, difficult to access in ex-periments, using unconventional method of analysing the dielectric relaxation spectra recorded for highly conductive donor-acceptor materials. In particular, we investigated how the dielectric properties of the conventionally used donor-acceptor P3HT:PCBM system will change when PCBM is replaced by a new acceptor, the imine SC2, or when the imine SC2 is added to this system. The dielectric studies in the broad frequency and temperature range were performed and the relaxation processes connected with the charge movements and with the dipolar rotation (beta relaxation) in systems based on polymer P3HT were extracted from the spectra. The relaxation times as well as the activation energies were obtained. Also the temperature dependence of the DC specific electric conductivity and high frequency permittivity for all materials studied were determined as well as the static permittivity for the P3HT:SC2 system.