Low frequency dielectric dispersions in the perylene + chloranil charge transfer complex

Abstract

The dielectric properties at 294 K of the perylene + chloranil complex have been studied over the frequency range 10^–4 to 10⁶ Hz. A dipolar-type dispersion is observed at ∼10^–2 Hz, with an apparent relaxation activation energy similar to previously reported semiconduction activation energies, and a relaxation time of the order of the characteristic relaxation time τ_D=ε₀ε_r/σ. No direct evidence could be found for the existence of interfacial polarisations, and an interpretation in terms of relaxations of the charge transfer dipole moment µ leads to an unrealistically large value for µ. An interpretation in terms of an activated hopping electron model is considered to be most likely, and is consistent with the Poole–Frenkel effects reported previously for this complex.