Effect of bismuth telluride concentration on the thermoelectric properties of PEDOT:PSS–glycerol organic films

Abstract

In this work, the effect of bismuth-telluride concentration on the thermoelectric properties of PEDOT:PSS–Glycerol thin films is investigated. A thermoelectric device was fabricated by depositing the n-type and the p-type Bi2Te3 (BT) doped-PEDOT:PSS–Glycerol on a glass substrate via a spin coating method at 500rpm. Room-temperature electrical properties characterization shows that the electrical conductivity of both type thin film increases with increasing of BT doping concentration and optimum at concentration of 0.8wt% for both p-type and n-type thin films, i.e. 17.9S/cm and 7.78S/cm, respectively. However, the study of the temperature effect on the thin films electrical conductivity suggested that the thermoelectric properties of both types' samples improved with increasing of BT concentration and optimum at 0.8 and 0.6wt% for p-type and n-type thin films, respectively. It then decreased if the BT concentration further increased. The Sebeeck coefficient for these samples is as high as −11.9 and −15.7uV/K, which is equivalent to a power factors of 0.26 and 0.19μSV2/ (mK2), respectively. A thermoelectric device resembling a thermocouple system that was fabricated using the optimum p-type and n-type thin films can generate a voltage as high as 1.1V at a temperature difference as low as 55K, which is equivalent to a maximum power of 6.026μW at Vmax.power of 0.5489V (for an estimated matched-load of 50Ω). The present materials system is potential for powering low power consumption electronic devices.