Conductivity and Density of States of New Polyphenylquinoline

Electrical, photoelectrical, and optical properties of thin films of a new heat-resistant polyphenylquinoline synthesized using facile methods were investigated. An analysis of the obtained temperature dependences of the dark conductivity and photoconductivity indicates the hopping mechanism of conductivity over localized states arranging at the energy distance of 0.8 eV from the Fermi level located inside the band gap of the investigated material. The optical band gap of the studied material was estimated from an analysis of the spectral dependences of the photoconductivity and absorption coefficient before (1.8-1.9 eV) and after (2.0-2.2 eV) annealing at temperatures exceeding 100 °C. The Gaussian character of the distribution of the localized states of density inside the band gap near the edges of the bands was established. A mechanism of changes in the optical band gap of the investigating polymer under its annealing is proposed.