Electrical and magnetic properties of poly(phenyleneaminochloranils)

Abstract

Electrical and magnetic properties of poly(phenyleneaminochloranils, (PPhCh) obtained from different aromatic diamines (donors) and chloranil or quinone (acceptors) have been investigated. For each PPhCh, the current-voltage characteristics at different temperatures were recorded and Ea, σ293 and σ0 values were determined. Some of the (log10I,ƒ(1/T)), curves showed a kink and lead to two Ea values. For high temperatures the compensation law was fulfilled and a single value of the parameters α and β was calculated for all the PPhCh investigated. The characteristic temperature Tc does not correspond to the Tk value, nor do the Ea values correspond to the 1E1 value of the repeating unit. It is probable that the Ea values are modified by trap levels distributed throughout the sample. In support of this view, the dependence of Ea on voltage was investigated, and the trap density for unit energy was found. The magnetic properties, i.e., the susceptibility χ0 related to free carriers, depend on polymer structure. The χ0 values decrease with decrease of donor polarity and increase when the electron affinity of acceptors increases, thus enhancing the electrical conductivity.