Charge transfer in poly(3-octylthiophene) modified by fullerene derivative

Magnetic, relaxation, and electronic dynamic parameters of paramagnetic centers stabilized in an initial and fullerene-modified poly(3-octylthiophene) (P3OT) were studied at the 3-cm (9.7 GHz) waveband EPR in wide (77–320 K) temperature region. Both the systems demonstrate sum spectrum of localized and mobile polarons, whose contribution depends on polymer treatment. Both spin susceptibility and spin–spin relaxation rate were shown to govern by dipole–dipole interaction of the mobile polarons. The spin–lattice and spin–spin relaxation times were determined separately by using the steady-state saturation method. It was shown that the treatment of the P3OT sample with fullerene molecules leads to the decrease in activation energy of spin susceptibility, dipole–dipole interaction, and interchain diffusion. This is accompanied by the acceleration of spin relaxation and increase in the system dimensionality.