Effects of the Interface between Inorganic and Organic Components in a Bi2Te3-Polypyrrole Bulk Composite on Its Thermoelectric Performance.

We provided a method to hybridize Bi2Te3 with polypyrrole, thus forming an inorganic/organic bulk composite (Bi2Te3-polypyrrole), in which the effects of energy band junction and phonon scattering were expected to occur at the interface of the two components. Bi2Te3-polypyrrole exhibited a considerably high Seebeck coefficient compared to pristine Bi2Te3, and thus it recorded a somewhat increased power factor despite the loss in electrical conductivity caused by the organic component, polypyrrole. Bi2Te3-polypyrrole also exhibited much lower thermal conductivity than pristine Bi2Te3 because of the phonon scattering effect at the interface. We successfully brought about the decoupling phenomenon of electrical and thermal properties by devising an inorganic/organic composite and adjusting its fabrication condition, thereby optimizing its thermoelectric performance, which is considered the predominant property for n-type binary Bi2Te3 reported so far.