Low thermal conductivity and high thermoelectric figure of merit in p-type Sb2Te3/poly(3,4-ethylenedioxythiophene) thermoelectric composites

Abstract

p-type Sb2Te3/poly(3,4-ethylenedioxythiophene) (PEDOT) thermoelectric composites are fabricated by embedding PEDOT into Sb2Te3 matrix. The grains of Sb2Te3 in the composites are found to be in micron degree and keep plate-like shapes. The measurements of thermoelectric properties show that the thermal conductivity κ of the composites is about 0.14 W m−1 K−1 in the temperature range of 300–523 K, much lower than that of Sb2Te3 compounds. The maximum of dimensionless figure of merit of the composites reaches to 1.18 at 523 K, which is the highest value for the reported Sb2Te3/organic composites. It is suggested that the plate-like Sb2Te3 grains and the embedded PEDOTs may play a significant role in decreasing the thermal conductivity. Furthermore, results of the thermal cycling between the room temperature and 523 K for 50 cycles show that the composites are stable with κ remaining a low value.