Thermoelectric Properties of Off-Stoichiometric Bi2Te2Se Compounds

Machine-learning guided prediction of thermoelectric properties of topological insulator Bi2Te3−xSex

“…Furthermore, the predicted thermoelectric properties of Bi 2 Te 3− x Se x with x = 1 using the random forest model are compared with the values calculated using the density functional theory (DFT) and Boltzmann transport theory. The electronic band structure of the Bi 2 Te 2 Se shows a band gap of around ∼0.186 eV, relatively larger than the Bi 2 Te 3 band gap of ∼0.14 eV, 55 and smaller than Bi 2 Se 3 (∼0.218 eV), 56 and consistent with the experimental 54 and theoretical 55 values. The Bi 2 Te 2 Se is a dynamically stable compound, which is confirmed by the first Brillouin zone phonon band structure and is in good agreement with the theoretical result.…”

“…57 The thermal conductivity, i.e. , κ DFT ( κ e-DFT + κ l-DFT ) of the Bi 2 Te 2 Se at 323 K calculated using DFT is ∼1.04 W m −1 K −1 , which is very close to the experimental 54 ( κ EXPT ∼ 1.01 W −1 K −1 ) and reported theoretical value 58 ( κ R-DFT ∼ 1.35 W m −1 K −1 ). As the temperature increases, the κ DFT of the Bi 2 Te 2 Se increases; however, its temperature-dependent κ EXPT shows a very small decrease with temperature.…”

“…The experimental values of κ of Bi 2 Te 3− x Se x span from 0.98 W m −1 K −1 to 1.33 W m −1 K −1 with distinct variations due to the change in Se concentrations. 54 Notably, the random forest model closely mirrors these trends, predicting κ values (ranging from 1.037 W m −1 K −1 to 1.297 W m −1 K −1 ) with remarkable precision (Fig. 6(a)).…”

“…The investigation of Bi 2 Te 3− x Se x alloys, encompassing compositions Bi 2 Te 1.95 Se 1.05 , Bi 2 Te 2.1 Se 0.9 , Bi 2 Te 2.01 Se 0.99 , Bi 2 Te 2.55 Se 0.45 , and Bi 2 Te 2.7 Se 0.3 , delves into the thermoelectric properties crucial for energy conversion applications. 54 The random forest model applied to predict four key thermoelectric parameters provides a detailed and nuanced analysis.…”

Improved thermoelectric performance of Bi2Se3 alloyed Bi2Te3 thin films via low pressure chemical vapour deposition

“…An alternative to the replacement of Bi2Te3 is to reduce the volume of material required to achieve the same or higher performance. For example, partial replacement of the low natural abundance of tellurium by selenium contributes strongly to a sustainable thermoelectric solution [15][16][17]. Several groups have produced ternary Bi2Te3-xSex thin films via electrodeposition [18][19][20][21][22][23][24][25], pulsed laser deposition [26], sputtering [27,28], and thermal evaporation [29][30][31].…”