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 E_a, σ₂₉₃ and σ₀ values were determined. Some of the (log₁₀I,ƒ(1/T)), curves showed a kink and lead to two E_a 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 T_c does not correspond to the T_k value, nor do the E_a values correspond to the ¹E₁ value of the repeating unit. It is probable that the E_a values are modified by trap levels distributed throughout the sample. In support of this view, the dependence of E_a 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.