This invention provides thermoelectric materials of Sb-doped bismuth telluride, Bi2-xSbxTe3-δ, where x is 1.51 – 1.59 and δ is 0 – 0.7. The dimensionless thermoelectric figure of merit (zT) of the bismuth telluride fabricated using hydrothermal methods followed by evacuated-and-encapsulated sintering technique can reach a value higher than 1.2. This material can be used as the p-leg of a thermoelectric module. This significant enhancement increases the efficiency of thermoelectric coolers (TEC) or generators (TEG).

The commercial bismuth antimonide alloys show the highest dimensionless figure of merit ZT ≈ 1, where T is the absolute temperature, between room temperature and 100 ºC. High ZT values of nanostructured Bi0.45Sb1.55Te3 for thermoelectric cooling or energy harvesting are fabricated by hydrothermal methods followed by evacuated-and encapsulating sintering.A zT = 1.65 at 290 K and 1.75 at 270 K are achieved with  60-70% improvement of that of the commercial state-of-the-art Bi2Te3 materials around room temperature. The significant ZT improvement arises from the much-reduced thermal conductivity. The low thermal conductivity is mainly due to the increased phonon scattering in the nanostructured materials.

1. Thermoelectric generators used in producing electricity outdoors (thermoelectric pots for smartphone charging and camp lamps);
2. Solid-state thermoelectric cooling in cooling diodes, medical uses (temperature controller and chillers), and portable refrigerators.