Improved thermoelectric performance of n-type BiTeSe based composites incorporated with PEDOT: PSS polymer nanoinclusions

Abstract

Many studies indicated that the thermoelectric performance of n-type Bi2Te2.7Se0.3 (BTS) was much more difficult to be elevated as compared to its p-type counterpart due to the frangible electron mobility of BTS. Here, the BTS based composites were designed and prepared by introducing the nanophase poly (3, 4-ethylidene dioxythiophene): Polystyrene sulfonate (PEDOT: PSS). As a result, due to the adjustment of the transport properties and strengthened energy filtering effect, the decreased electrical resistivity and enhanced thermopower were obtained, thus leading to the significant improvement of power factor in the whole investigated temperature range. Meanwhile, the lattice thermal conductivity of the composites was sharply reduced by enhanced phonon scattering, reaching a minimum of 0.33 W m−1 K−1 (at 300 K). As a result, the larger ZTmax = 1.23 @415 K and higher ZTave = 1.15 (300–500 K) are achieved for the composite sample xPEDOT: PSS/BTS with x = 0.5 wt%. Moreover, our fabricated single-leg device made of composites shows an energy conversion efficiency of 3.03% (at ΔT = 225 K) that is ∼53% higher than that of the same device made of a commercial BTS ingot, demonstrating that incorporation of nanophase PEDOT: PSS in BTS is effective way in improving its thermoelectric performance.