Bi<inf>2</inf>Se<inf>3</inf>-PVDF composite: A flexible thermoelectric system

We report the thermoelectric properties of flexible Bi2Se3-Polyvinylidene fluoride (PVDF) based polymer nanocomposites (PNC) over a temperature range from 250 K to 350 K. The two-dimensional Bi2Se3with nanoplate like structure is synthesized using the reflux method and is dispersed with the PVDF matrix. A significant reduction in the thermal conductivity of the PNC in comparison to the individual phases of Bi2Se3 and PVDF is observed. The overall thermal conductivity value of the PNC is measured to be 0.06 W/m-K at 300 K. An order of magnitude reduction in the thermal conductivity in the PNC is explained using the acoustic impedance model. The Seebeck coefficient and the electrical conductivity are decreasing with the addition of PVDF to Bi2Se3. The figure of merit of PNC is determined to be about 0.004 at 300 K, and the flexible nature of Bi2Se3-PVDF nanocomposites is also demonstrated. The mechanical properties of the PNC are quantitatively measured using nanoindentation technique.