Revealing enhanced thermoelectric performance of tin-bismuth-telluride materials

A tin–bismuth–telluride material was confirmed as an efficient and harmless material in thermoelectric applications by the results obtained from the density functional theory. The calculations were carried out using the FP-LAPW method with Wien2k code. This is the classic thermoelectric material used in refrigeration and thermoelectric generators due to its high Seebeck coefficient value and low thermal conductivity. Here Tin is replaced in parent SnTe by bismuth as various doping concentrations. The spin-orbit coupling was used in both electronic and thermoelectric properties calculations. Also we discussed mechanical properties of Sn (1– x ) Bi x Te ( x = 0, 0.125, 0.25, 0.5, 0.75, 0.875 and 1) materials. The result confirms that all the doped materials are ductile in nature and parent SnTe is of brittle nature. Here we have discussed the results on both spin-orbit coupling (SOC) and non-SOC calculations in thermoelectric properties. Changes occurred in band structure, and density of states according to SOC and non-SOC calculations were clearly explained. Also, the calculations of Seebeck coefficient, electrical conductivity with relaxation time, power factor, electronic thermal conductivity and figure of merit were made with SOC and without SOC over the temperature range of 300–1000 K. From the results, it was obtained that, within the SOC calculations, thermoelectric properties of the studied materials were enhanced at high temperature.