Facile Solution Synthesis, Processing and Characterization of n- and p-Type Binary and Ternary Bi–Sb Tellurides

Abstract

The solution synthesis route as a scalable bottom-up synthetic method possesses significant advantages for synthesizing nanostructured bulk thermoelectric (TE) materials with improved performance. Tuning the composition of the materials directly in the solution, without needing any further processing, is important for adjusting the dominant carrier type. Here, we report a very rapid (2 min) and high yield (>8 g/batch) synthetic method using microwave-assisted heating, for the controlled growth of Bi2–xSbxTe3 (x: 0–2) nanoplatelets. Resultant materials exhibit a high crystallinity and phase purity, as characterized by XRD, and platelet morphology, as revealed by SEM. Surface chemistry of as-made materials showed a mixture of metallic and oxide phases, as evidenced by XPS. Zeta-potential analysis exhibited a systematic change of isoelectric point as a function of the material composition. As-made materials were directly sintered into pellets by using spark plasma sintering process. TE performance of Bi2−xSbxTe3 pellets were studied, where the highest ZT values of 1.04 (at 440 K) for Bi2Te3 and 1.37 (at 523 K) for Sb2Te3 were obtained, as n- and p-type TE materials. The presented microwave-assisted synthesis method is energy effective, a truly scalable and reproducible method, paving the way for large scale production and implementation of towards large-area TE applications.

Minute-Made, High-Efficiency Nanostructured Bi2Te3 via High-Throughput Green Solution Chemical Synthesis

“…Bottom up chemical methods are commonly used because of their low cost, low investment need and possibility of scale-up of the synthesis process [ 26 ]. Different morphologies of Bi 2−x Sb x Te 3 including nanoparticles, nanoplates, nanocrystalline films, nanorods, nanotubes, nanowires and nanoflowers have been synthesized by reverse micelle [ 27 ], metal-organic chemical vapor deposition (MOCVD) [ 28 , 29 , 30 ], vapor–liquid–solid (VLS) [ 31 , 32 ], refluxing [ 33 , 34 , 35 , 36 ], electrodeposition [ 37 , 38 ], chemical reduction [ 39 , 40 ], solvothermal [ 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ], hydrothermal [ 26 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ], ultrasonic-assisted [ 59 , 60 , 61 ], and microwave (MW)-assisted [ 62 , 63 , 64 , 65 , 66 ] routes, to name a few. Among all these chemical syntheses methods, solvothermal/hydrothermal routes are the preferred methods to prepare nanostructures with different morphologies.…”

Geometric optimization of thermoelectric generator using genetic algorithm considering contact resistance and Thomson effect

“…Research and optimization of the thermoelectric materials which will enhance the material figure of merit are underway. [7][8][9][10][11][12][13][14][15][16] The material figure of merit is given as z = α 2 σ/k, where α is Seebeck coefficient, σ is electrical conductivity and k is the thermal conductivity of the material. The influence of contact resistance and heat losses on the output performance of thermoelectric modules have been investigated by many researchers.…”

“…The performance of a thermoelectric module is determined by the properties of the thermoelectric materials, geometrical design, electrical and thermal contact resistances, radiation and convection losses, electrical load matching and cooling system. Research and optimization of the thermoelectric materials which will enhance the material figure of merit are underway 7‐16 . The material figure of merit is given as z = α 2 σ / k , where α is Seebeck coefficient, σ is electrical conductivity and k is the thermal conductivity of the material.…”

A Comparative Study on the Thermoelectric Properties of Bismuth Chalcogenide Alloys Synthesized through Mechanochemical Alloying and Microwave-Assisted Solution Synthesis Routes

“…Various morphologies including nanoparticles (Cao et al, 2008;Jiang and Zhu, 2007), nanosheets (Shi et al, 2008;Li et al, 2010), films (Li et al, 2006), nanowires (Yu et al, 2004), hollow nanospheres (Li et al, 2006), and nanorods/nanotubes (Prieto et al, 2001, Zhao et al, 2005Xiao et al, 2007;Li et al, 2009) have been reported. Microwave (MW)-assisted heating has been demonstrated to be practical for the synthesis of binary and ternary TE nanomaterial compositions directly in the solution phase (Kumar et al, 2020;Hamawandi et al, 2020a;Hamawandi et al, 2020b), without needing further processing. Reactions that have lasted several hours to days have been realized in a fraction of the time using MW-assisted heating.…”

“…MW reaction time can be shortened to a fraction of conventional synthetic routes, due to special dielectric heating (Anastas and Lankey, 2002). Among the most significant achievements, our recent work demonstrating a scalable MWassisted synthesis (2 min reaction time) of a series of Bi 2−x Sb x Te 3 compounds with moderate to high ZT (Hamawandi et al, 2020b) can be listed.…”