Electrical conductivity and dielectric relaxation of bulk iron (III) chloride tetraphenylporphyrin

The electrical conductivity and dielectric properties of bulk iron (III) chloride tetraphenylporphyrin, FeTPPCl, has been investigated in the frequency range from 40 Hz to 5 MHz and in the temperature range of 298–373 K. The frequency dependence of σ(ω, T) follows the Jonscherʹs universal dynamic law. The temperature behaviour of the frequency exponents shows that the correlated barrier hopping (CBH) model is well adapted to FeTPPCl semiconductor material. The conductivity in the direct regime, σdc, is described by the variable range hopping (VRH). In spite of the absence of the dielectric loss peaks, application of the dielectric modulus formulism gives a simple method for evaluating the activation energy of the dielectric relaxation.