An unusual coral-like morphology for composites of poly(3,4-ethylenedioxythiophene)/carbon nanotube and the enhanced thermoelectric performance

We present an unusual coral-like coating morphology for the poly(3,4-ethylenedioxythiophene)/carbon nanotube (PEDOT/CNT) composites with dramatically improved thermoelectric performance. First, the PEDOT/CNT composites are prepared via chemical oxidation polymerization procedure in reverse microemulsions, using hexane or xylene as the reaction medium. The composite films exhibit excellent mechanical flexibility against bending and twisting. Then, the cable-like (in hexane) or coral-like (in xylene) morphology for the thick and uniform coating layer is directly proved by field-emission scanning electron microscopic images. Subsequently, their thermoelectric performances are quantitatively measured at room temperature. After that, the ordered arrangement structures of PEDOT macromolecules, the level of doping and the level of oxidation are investigated by X-ray diffraction technique and X-ray photoelectron spectra, respectively. Finally, the molecular mechanism for the enhanced thermoelectric performance is discussed.