On the electronic transport in some new synthesized high resistivity organic semiconductors in thin films

The study of temperature dependence of electrical conductivity, σ, and Seebeck coefficient, α, for six new synthesized organic salts, namely N-(p-R-phenacyl)-1,10-phenanthrolinium bromides, is reported. Thin film samples (d=0.51–1.76 μm) deposited from dimethylformamide solutions onto glass substrates were been used. The inspection of samples surface was performed by means of atomic force microscopy and metallographic microscopy techniques. The experimental obtained curves σ(T) and α(T) are typical for semiconducting materials. The study of Seebeck effect revealed a p-type electrical conduction mechanism of examined organic films. Using the experimental data, the values of some characteristic parameters for respective compounds (the thermal activation energy of electrical conduction, ΔE, the ratio of carrier mobilities, b, etc.) have been determined. The obtained values of ΔE ranged from 1.70 to 2.80 eV. Some correlations between these values and molecular configurations of the studied compounds are established.