Conductivity and photoconductivity in benzene and pyridine

Dark currents in benzene and pyridine have been studied through a range of temperatures including the melting point for a variety of electrode materials, electrode spacings and applied potentials. Photocurrents have also been studied, the parameters specified above and the wavelength range of the incident photons all being varied. It is deduced that in the liquid state the current is carried by ions, and in the solid state by electrons. The results obtained can be interpreted in terms of a combination of bulk and electrode phenomena, the former being dominant for large electrode spacings and the latter for small electrode spacings. In pyridine for small electrode spacing an apparent negative photoconductivity is observed.