Enhanced figure of merit of poly(9,9-di-n-octylfluorene-alt-benzothiadiazole) and SWCNT thermoelectric composites by doping with FeCl₃

Abstract

Poly(9,9-di-n-octylfluorene-alt-benzothiadiazole (F8BT) generally has a large Seebeck coefficient, and single-walled carbon nanotubes (SWCNTs) have high electrical conductivity. In this work, we prepared F8BT/SWCNT composites to combine the good Seebeck coefficient of the polymer and the excellent electrical conductivity of SWCNTs to achieve enhanced thermoelectric properties. For the composite materials, the maximum power factor of 1 μW mK−2 was achieved when the SWCNT content was 60%, with the maximum ZT value of 4.6 × 10−4. After ferric chloride was employed as the oxidative dopant for the composites, the electrical conductivity of the composites improved significantly. The maximum value of power factor (1.7 μW mK−2) was achieved when the SWCNT content was 60%, and the ZT value of 7.1 × 10−4 was about 1.5 times as high as that of the composites with undoped F8BT.