The charge storage and other electrical properties of a series of polyacene quinone radical polymers

Abstract

A series of polyacene quinone radical polymers were made. The chemical analysis showed that the severe reaction conditions favored the Scholl (elimination of H2 and H2O) over the Friedel–Crafts reaction. Electron paramagnetic resonance spectra confirmed the presence of a biradical. Conductivity measurements in the ohmic and space charge limited regions showed that large π systems existed and that carrier traps were shallow. The π system structure and absence of quinone structure was confirmed by ir spectrometry which also showed the optical absorption edge to be 0.8 eV. Charge was injected into the polymers forming electrets and thermally stimulated current emission spectra confirmed a shallow trap depth (∼0.4 eV). It is postulated that thermal excitation to a triplet state produces the biradical and conduction is by hopping between adjacent π systems and charge storage is associated with the extensive π systems.