N-type doping and thermoelectric properties of co-sublimed cesium-carbonate-doped fullerene

Organic semiconductors exhibit a large Seebeck coefficient and a poor thermal conductivity allowing them to become strong candidates for thermoelectric applications. These materials have been widely used in organic electronics with the fabrication of organic light-emitting diodes, organic solar cells, and transistors. However, few studies have reported on thermoelectric properties of organic materials even though they offer specific advantages such as cost-effectiveness and flexibility. In this article, we discuss the fabrication and characterization of fullerene C60 doped with cesium carbonate (Cs2CO3). The evolution of the morphology, electrical conductivity, and Seebeck coefficient was analyzed as a function of the dopant concentration. An optimal power factor of 28.8 μWm−1 K−2 was obtained at room temperature for a molar ratio of 15.2 %. Thus far, this power factor value constitutes the best thermoelectric performance achieved with N-type organic materials.