Influence of sintering temperature on thermoelectric properties of BiTe/Polythiophene composite materials.

BiTe/Polythiophene (PTH) thermoelectric bulk composite materials were prepared by a two-step method. Firstly, BiTe and PTH nanopowders were prepared by hydrothermal synthesis and chemical oxidative polymerization, respectively. Secondly, the mixture of the BiTe and PTH nanopowders (50:50 wt) was pressed under vacuum at 80 MPa and 298, 473, or 623 K. For comparison, BiTe powders were hot pressed at 623 K. The bulk materials were analyzed by conventional methods, such as X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis (TGA) and field emission scanning electron microscopy equipped with electron dispersive X-ray spectroscopy. The XRD and TGA results showed that the PTH decomposed when the hot pressing temperature exceeded 473 K, and BiTeS phase was formed. The thermoelectric properties of the bulk composite materials were investigated. The composite pressed at 623 K showed a higher power factor, ~2.54 μ Wm K at 473 K, which is as ~20 times as that of the composite pressed at 473 K, although, it is still much lower than that of the pressed BiTe material (~1,266 μ Wm K at 348 K). [ABSTRACT FROM AUTHOR]