A study of the synthesis of bismuth tellurium selenide nanocompounds and procedures for improving their thermoelectric performance

Highlights: → A Bi2TeySe3-y nanocompound was successfully synthesized via a chemical process. Its theoretical fabrication mechanism was established. → It exhibited remarkably lower thermal conductivity than a conventional material. → We also adjusted its physical and electrical properties via various procedures. This resulted in the improvement of thermoelectric performance. - Abstract: A bismuth tellurium selenide (Bi2TeySe3-y) nanocompound for thermoelectric applications was successfully prepared via a water-based chemical reaction in an atmospheric environment. The compound was less that ca. 100 nm in size, with a crystalline structure corresponding to the rhombohedral Bi2Te2.7Se0.3. We sintered the compound via a spark plasma sintering process under the designated sintering conditions and measured the transport properties (i.e., thermal conductivity, resistivity, Seebeck coefficient). The resulting specimens consisted of nanosized grains exhibiting a remarkably low thermal conductivity. Subsequently, we endeavored to improve the other transport properties by adjusting the carrier density of the compound and derived the overall thermoelectric performance by the figure of merit (ZT).