Electro-conductive properties of cadmium octanoate composites with CdS nanoparticles

Abstract

Electrical properties of mesogenic cadmium octanoate composites containing CdS nanoparticles (NPs) have been studied for the first time. Semiconductor CdS spherical NPs (sizes of 2.5 nm) were chemically synthesized in the thermotropic ionic liquid crystalline phase (smectic A) of cadmium octanoate that was used as nanoreactor. We compared the electrical properties of both clean matrix and nanocomposite to clarify the role of semiconductor CdS NPs with different concentrations. We have investigated electrical characteristics at different temperatures, which correspond to the different phases of the composites. The conductivity of nanocomposites has an activation nature both in anisotropic glassy and smectic A phase. The conductivity of the nanocomposite along the cation-anion layers is by two orders of magnitude higher than that across the cation-anion layers, which confirms anisotropy of the nanocomposite regardless of the phase of material. In the glassy phase, the electronic type conductivity is observed. Increasing the nanoparticles concentration brings additional free charge carriers or increases their mobility. For the smectic A phase, increasing the CdS NPs concentration brings additional traps for the carriers that travel in plane of the cation-anion layers. On the other hand, the nanoparticles deform the cation-anion layers and increase the mobility of carriers across the layers.