Nanostructured Semiconducting PEDOT−TiO2/ZnO Hybrid Composites for Nanodevice Applications

Abstract

In this paper, we have developed a simple strategy for the preparation of hybrid nanocomposites of poly(3,4-ethylenedioxythiophene)− TiO2/ZnO (PZT) and demonstrated its application in a thermoelectric device. Hierarchical hetero-nanostructured TiO2/ZnO (ZTO) was prepared by a facile sol−gel process in the presence of a biocapping agent. PZT was prepared by in situ polymerization of EDOT in the presence of ZTO. It was characterized by UV−visible, FT-IR, XRD, Raman, SEM, TEM, and AFM analyses. Results revealed homogeneous distribution of ZTO with a heterocrystalline phase of wurtzite ZnO/anatase TiO2 having high density of various defects in the hybrid nanocomposite. Studies showed that ZTO is excellently interfaced with highly ordered selfassembled extended π-layers of PEDOT chains, which could enhance the charge carrier concentration (3.92 × 1020 cm−3) and charge carrier mobility (0.83 cm2 V−1 s−1). Furthermore, we have demonstrated its application as a thermoelectric material by fabricating the device (Cu/PZT/Cu), which showed low thermal conductivity of 0.0495 Wm−1K−1, Seebeck coefficient of 19.05 μV K−1, power factor of 1.28 μW m−1K−2, and figure of merit of 4.8 × 10−3 at ambient temperature. All of these excellent material properties of PZT suggest its application as an active material for the fabrication of nanoelectronic devices with large area.