Electrical conduction mechanism in N-(p-R-phenacyl)-4,5-diazafluorenium-9-one bromides thin films

Abstract The synthesis and the study of temperature dependence of the electrical conductivity, σ , and Seebeck coefficient, S , for some new organic salts, N -( p -R-phenacyl)-4,5-diazafluorenium-9-one bromides, in thin films, is reported. The dependences ln  σ (10 3 / T ) and S (10 3 / T ) are typical for p-type semiconducting compounds. The values of some characteristic parameters for the examined compounds (the thermal activation energy of electrical conduction, Δ E , the ratio of carrier mobilities, b , etc.) have been determined. The obtained values of Δ E ranged from 1.71 and 2.01 eV, while those of b lay in the range 0.70–0.87. The analysis of the absorption edge evidenced direct energy gaps, ranged between 3.31 and 3.39 eV, as well the presence of Urbach absorption tails. Some correlations between respective values and molecular configurations of the present organic salts are established. The model based on band gap representation is suitable for the explanation of the electronic transfer mechanism in the investigated compounds.