Diffusion of Charged Species in Metal Oxides and Polymeric Solids Using AC Impedance Technique

Abstract

The diffusion of charged species in solids is a very important part of the study of the electrical properties of materials. Electrical measurements using alternating current (ac) impedance is a powerful technique to study diffusing species in metal oxides as well as polymers. Three case studies are being presented here whereby the electrical properties of LiTaO3, Poly[2-methoxy-5-(2’-ethylhexyloxy)-(p-phenylenevinylene)] (MEH-PPV) and its composite are being studied using the same ac impedance technique. LiTaO3 is a metal oxide while MEH-PPV is a polymer. They are very different and therefore present very good examples for the versatility and power of ac impedance method. Electrical parameters such as conductivity and conduction behaviours of the conducting species can be extracted from the studies. The kinetics of the diffusing species can be elucidated by using proper analytical techniques.

Improving the electrical properties of poly[2‐methoxy‐5‐(2‐ethylhexyloxy)‐1,4‐phenylenevinylene] by doping with camphor sulfonic acid for energy storage applications

“…They showed that the conductivity increases from 4.94 Â 10 À9 SÁcm À1 to 4.04Â 10 À7 SÁcm À1 due to MCMB doping. Additionally, they obtained the decreasing activation energies from 0.64 to 0.61 eV at 323 K. 14 Similarly, when Kareev et al compared the activation energy of MEH-PPV and 20 mol% MEH-PPV/C60 (fullerene) films, they reported that the activation energy of MEH-PPV decreased from 0.65 to 0.47 eV. 15 On the other hand, a study examining the energy storage performance of MEH-PPV has not been found in the scientific literature.…”