Thermoelectric properties of polyvinylpyrrolidone/polyaniline-mixed Bi2Te3 composites prepared by electrospinning

Composite fibers of bismuth telluride (Bi2Te3) with polyaniline (PANI) and polyvinylpyrrolidone (PVP), synthesized via electrospinning in different ratios, were studied. Initially, three solutions were synthesized in different ratios of PVP and composite (Bi2Te3 and PANI). However, due to the loading capacity of polymer only two samples were successfully synthesized. The formation and surface morphology of as-prepared and compacted fibers were studied by scanning electron microscopy. The X-ray diffraction confirmed the increase in crystalline phase of the composites after compaction. The influence of functional groups on the thermal and electrical conductivity as well as the existence of various polymer functional groups in pure and composite samples were revealed by Fourier transform infrared spectroscopy. Thermogravimetric analysis and differential scanning calorimetric were carried out simultaneously up to 800 K, which revealed the thermal stability of composite up-to 473 K and a glass transition temperature (T-g) of similar to 412 K for the composites. Diffuse reflectance spectroscopy confirmed the decrease in the bandgap from similar to 3 to similar to 1.2 eV of the compacted fibers. The thermopower of the as-prepared and compacted fibers increased significantly compared with pure Bi2Te3 and PANI, while the thermal conductivity decreased to 0.45 Wm(-1) K-1. As a result, zT was enhanced from 1.7 x 10(-10) to 1.7 x 10(-1) in the composite samples near room temperature.

Automated summary

Composite fibers of bismuth telluride with polyaniline and polyvinylpyrrolidone were synthesized via electrospinning. The morphology and surface morphology of the fibers were studied using scanning electron microscopy. The X-ray diffraction and Fourier transform infrared spectroscopy confirmed the increase in crystalline phase and revealed the influence of functional groups. The thermogravimetric analysis and diffuse reflectance spectroscopy showed the thermal stability and decreased bandgap of the composite fibers.