Charge transport in chemically synthesized, DNA-doped polypyrrole

Abstract

The charge transport properties of chemically synthesized, DNA-doped polypyrrole (PPY) are described here. The polymer showed a significant change in microstructural morphology and optical absorption spectra with increase in DNA concentrations (0.36–14% w/v). Both the dark and photo-induced I–V characteristics of the polymers showed an increase in the degree of linearity with increase in DNA concentration. The temperature-dependent dc electrical conductivity (σ) exhibited a significant dependence on the nature of carrier hopping dominant in this DNA-doped PPY: σ showed a change from T−1/4 to T−1/2 dependence on temperature as the degree of doping increased from 0.36% to 3%, respectively. Further increase in DNA doping to 14% led to a T−1 dependence of the dc electrical conductivity. The results were interpreted in terms of the localized polaronic and bipolaronic states caused by the disorder in polymeric chains, variation in chain length, interchain interactions, etc.