Thermal stability of n-type zone-melting Bi₂(Te, Se)₃ alloys for thermoelectric generation

Thermal Stability and Mechanical Response of Bi2Te3-Based Materials for Thermoelectric Applications

“…The reduced density mainly results from the accelerated sublimation of tellurium component at above 523 K. The volume expansion could be ascribed to the mismatch of thermal expansion coefficient between excess tellurium and the Bi 0.5 Sb 1.5 Te 3 matrix, which can generate cracks or voids in the prolonged annealing process. 36 Meanwhile, the hole concentration shows a decreasing trend with increasing annealing The zone-melted Bi 2 Te 3 -based ingots exhibit preferential orientation in the microstructure and thus weak mechanical responses along the van der Waals gap. Thus, extensive efforts have been invested to develop various powder metallurgy methods to prepare polycrystalline Bi 2 Te 3 -based bulk materials, which demonstrate both improved mechanical properties and TE performance.…”

“…12,35 Recently, ptype Bi 0.5 Sb 1.5 Te 3 ZM ingots and MS-PAS bulks were subjected to the thermal annealing process in vacuum (Figure 2a) at 473 and 573 K, respectively, for 1 week. 36 MS-PAS samples exhibit excellent stabilities at 473 K, while ZM counterparts remain stable up to 573 K. The power factor of MS-PAS samples annealed at 573 K has been reduced significantly due to the substantial decrease in the hole concentration. This could be correlated with tellurium sublimation at 573 K accompanied by obvious bloating on the sample surface (Figure 2b).…”

“…59 It is evident that porosity can be generated along with the tellurium sublimation when Bi 2 Te 3 -based materials are subjected to thermal treatment. 36,42 Moreover, the process of powder consolidation can also introduce porosity in Bi 2 Te 3 -based bulk materials which can be regulated through temperature or pressure control in the consolidation process. 60 These methods for thermally induced porosity play a vital role in affecting the TE properties, which can scatter both electrons and phonons and result in simultaneous reductions in electrical and thermal conductivities.…”

Scalable colloidal synthesis of Bi2Te2.7Se0.3 plate-like particles give access to a high-performing n-type thermoelectric material for low temperature application

“…Experimentally, the anisotropy in the electrical transport between the ab-plane and the c-axis of single crystalline Bi2Te3 alloys has been widely recognized especially in ingots made from unidirectional crystal growing methods. 31,58 Also, Bi2Te3 and its alloys were found to be susceptible to deformation-induced defects which affects the electrical transport properties. 16,19,30 Hence, in the BTS consolidated from plate-like particles, the temperature dependent anisotropy in electrical transport properties of bulk BTS samples were examined in both inplane and cross-plane direction for three subsequent run as shown in supplementary information Figure S3.…”

Regularities of Structure Formation in 30 mm Rods of Thermoelectric Material during Hot Extrusion

“…The most widely used technologies of Bi 2 Te 3 based materials are zone melting [6][7][8], spark plasma sintering [9][10][11][12], and hot extrusion [13][14][15]. The preferable technology is hot extrusion for which plastic strain produces a predominant grain orientation (i.e., a texture) in the polycrystalline material and, as a result, the final ingots exhibit good mechanical and thermoelectric properties [16][17][18].…”