Enhanced Thermoelectric Properties of p-Type Bi_0.48Sb_1.52Te₃/Sb₂Te₃ Composite

Abstract

Constructing a nanocomposite to introduce a coherent interface is an effective way to improve the property of thermoelectric material. Here, a series composites of Bi 0.48 Sb 1.52 Te 3 −x wt % Sb 2 Te 3 (x = 0, 0.3, 0.5, 0.8, and 1.0) were synthesized, where the hydrothermally prepared Sb 2 Te 3 nanosheets were intimately wrapped in the solid-state-reacted Bi 0.48 Sb 1.52 Te 3 matrix. The formation of a coherent interface was observed and confirmed by the scanning electron microscopy characterization. As the Sb 2 Te 3 content was over 0.5 wt %, the carrier mobility could increase by 26%, while the carrier concentration decreased by 9% compared to those of the pure matrix at 300 K, enhancing the power factor to 40.1 μW/cm K 2 . Moreover, the Bi 0.48 Sb 1.52 Te 3 −0.5 wt % Sb 2 Te 3 sample exhibited a reduced lattice thermal conductivity of 0.83 W/m K at room temperature, resulting from the strengthened phonon scattering by interfaces. Combined with the manipulations of both the electronic and thermal transport by constructing a coherent interface, a maximum ZT of 1.05 was obtained in the x = 0.5 composite at 300 K, and it was improved by 20% compared with the result of the Bi 0.48 Sb 1.52 Te 3 matrix.

Enhancement of Thermoelectric Properties of n-Type Bi2Te3–xSex by Energy Filtering Effect

“…There are several ways to obtain evidence of the EFE, but confirmation by Pisarenko plots is commonly done. ,, In this study, we adopted the Pisarenko plot based on these previous studies. It is also reported that the increase of the scattering parameter must be confirmed in order to obtain more reliable evidence of the EFE …”

“…In this study, we focused on improving S thorough the energy filtering effect (EFE). − The EFE is applied in composites by forming potential barriers that scatter the charge carriers with lower energy than the potential energy, while the charge carriers with higher energy can contribute to the transport. (CuI) 0.003 Bi 2 Te 2.7 Se 0.3 /Mo, Bi 2 Te 2.7 Se 0.3 /GaAs, (Bi,Sb) 2 (Te,Se) 3 /Te, (Bi,Sb) 2 Te 3 /PbSe, Bi 2 Te 3 /graphene, Bi 0.5 Sb 1.5 Te 3 /Sb 2 O 3 , Bi 0.48 Sb 1.52 Te 3 /Sb 2 Te 3 , and Bi 0.4 Sb 1.6 Te 3 /FeTe 2 are some of the successful examples of the EFE in a Bi 2 Te 3 -based alloy. − …”

Current State‐of‐the‐Art in the Interface/Surface Modification of Thermoelectric Materials

“…dispersed Sb 2 Te 3 into a Bi 0.48 Sb 1.52 Te 3 matrix. [ 128 ] The phase boundaries between the nanoinclusions and the matrix created an effective barrier which improved the PF and increased the effective mass m *. The interface potential barriers can obstruct low‐energy carriers, potentially suppressing the bipolar effect and leading to an obvious increase in carrier mobility, along with a slight decrease in carrier concentration.…”

Synergistically Optimized Thermoelectric and Mechanical Properties in p‐Type BiSbTe by a Microdroplet Deposition Technique

“…Aiming at better mechanical property, Bi 2 Te 3 ‐based polycrystalline bulks were prepared using sintering methods, such as melt spinning, [ 22 ] microwave sintering, [ 23 ] spark plasma sintering, [ 24–27 ] shear/hot extrusion, [ 28–30 ] liquid‐phase pressing, [ 31,32 ] hot pressing/deformation, [ 33–40 ] and so on. For these methods, the temperature gradient is relatively small along the uniaxial direction during the sintering process; the powder particle with low orientation hardly melts, and thus, the sintered product exhibits a weak degree of texture.…”

“…However, the zone-melting Bi 2 Te 3 ingots exhibit poor mechanical properties and are easy to cleavage along the basal plane, which seriously limit the reliability of thermoelectric devices, especially the micromodules. [20,21] Aiming at better mechanical property, Bi 2 Te 3 -based polycrystalline bulks were prepared using sintering methods, such as melt spinning, [22] microwave sintering, [23] spark plasma sintering, [24][25][26][27] shear/hot extrusion, [28][29][30] liquid-phase pressing, [31,32] hot pressing/deformation, [33][34][35][36][37][38][39][40] and so on. For these methods, the temperature gradient is relatively small along the uniaxial direction during the sintering process; the powder particle with low orientation hardly melts, and thus, the sintered product exhibits a weak degree of texture.…”