Comparative Study of Thermoelectric Properties of Sb₂Si₂Te₆ and Bi₂Si₂Te₆

Abstract

Charge carrier transport and corresponding thermoelectric properties are often affected by several parameters, necessitating a thorough comparative study for a profound understanding of the detailed conduction mechanism. Here, as a model system, we compare the electronic transport properties of two layered semiconductors, Sb 2 Si 2 Te 6 and Bi 2 Si 2 Te 6 . Both materials have similar grain sizes and morphologies, yet their conduction characteristics are significantly different. We found that phase boundary scattering can be one of the main factors for Bi 2 Si 2 Te 6 to experience significant charge carrier scattering, whereas Sb 2 Si 2 Te 6 is relatively unaffected by the phenomenon. Furthermore, extensive point defect scattering in Sb 2 Si 2 Te 6 significantly reduces its lattice thermal conductivity and results in high zT values across a broad temperature range. These findings provide novel insights into electron transport within these materials and should lead to strategies for further improving their thermoelectric performance.

Enhanced Thermoelectric Properties and Flexibility of 2D Bi2Si2Te6 Nanosheets and PEDOT:PSS-Based Thermoelectric Composites

“…The changes in electrical conductivity and Seebeck coefficient with temperature is driven by the carrier mobility and bipolar conduction. Additionally, the TE properties of Bi 2 Si 2 Te 6 NS/PEDOT:PSS composite film according to temperature is similar to that of other TE materials using Bi 2 Si 2 Te 6 . − …”

“…The crystal structure of the Bi 2 Si 2 Te 6 is shown in Figure b. Thus, the as-fabricated Bi 2 Si 2 Te 6 crystallizes in a rhombohedral crystal structure belonging to the space group R 3̅. − The Bi 2 Si 2 Te 6 slabs are stacked along the c -axis via van der Waals interactions. The slabs consist of the Bi atoms at the center of the BiTe 6 octahedra and the ethane-like Si 2 Te 6 .…”

“…Recently, Bi 2 Si 2 Te 6 with a 2D layer structure has been studied as a potential high-performance p-type TE material. − Similar to Sb 2 Si 2 Te 6 , Bi 2 Si 2 Te 6 has a layered rhombohedral crystal structure (space group R 3̅) with three crystallographic positions. − Single crystalline Bi 2 Si 2 Te 6 has been reported to exhibit a large Seebeck coefficient and low lattice thermal conductivity. , However, pristine Bi 2 Si 2 Te 6 is not suitable for flexible TE materials due to the low flexibility of inorganic materials. Hence, in the present study, a design for improving the TE performance is proposed by incorporating Bi 2 Si 2 Te 6 NSs with the PEDOT:PSS conductive polymer matrix.…”

Development of Nanostructured Bi2Te3 with High Thermoelectric Performance by Scalable Synthesis and Microstructure Manipulations

“…Consequently, it exhibits a power factor (PF) value as high as 19 μW cm –1 K –2 , which is much higher than those previously reported for chemically synthesized Bi 2 Te 3 (Figure c). ,, Compared with bulk Bi 2 Te 3 , the increase of the Seebeck coefficient as well as electrical conductivity with temperature strongly suggests that nanostructuring due to the solution synthesis induces a favorable change in the Fermi surface topology. Jang et al revealed that suppression of scattering at heterointerfaces does not degrade electronic properties, and therefore second phases with coherent interfaces with the matrix can limit the detrimental effects on charge carrier mobility . In our study, the established semicoherent interfaces and low-potential barriers at the conduction band of BT2 could result from the special nanostructured Bi 2 Te 3 with GBs decorated by Te nanoparticles; therefore, the unfavorable effect on electronic properties and mobility does not appear.…”

Suppressing Charged Cation Antisites via Se Vapor Annealing Enables p‐Type Dopability in AgBiSe2–SnSe Thermoelectrics

“…The speed of sound was measured by the pulse‐echo method, where an initial stress wave of ultrasonic pulse was sent and received by an identical piezoelectric transducer. [ 63 ] A longitudinal transducer with a center frequency of 5 MHz (CMR‐052, ndtXducer) and a normal incidence shear transducer with an identical frequency (SM‐052, ndtXducer) for measuring longitudinal and transverse sound velocities were used, respectively. The ultrasonic pulse signals were manipulated using an ultrasonic pulser/receiver (DPR 300, JSR Ultrasonics) and corresponding waveform was recorded using a digital oscilloscope (DSO‐X 2022A, Keysight).…”