Enhancement in thermoelectric properties due to Ag nanoparticles incorporated in Bi2Te3 matrix (original) (raw)
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A review on bismuth telluride (Bi 2 Te 3 ) nanostructure for thermoelectric applications
Bismuth Telluride (Bi 2 Te 3 ) is basically known as an efficient thermoelectric material. Nowadays, it has been attracted a great deal of interest in energy harvesting, chip cooling, chip sensing and other field of material science because of its potential applications. In order to produce Bi 2 Te 3 nanostructure, a number of methods such as solvo and hydro thermal, refluxing, straight forward arc-melting and polyol methods have been employed. Among of them, the solvothermal method has been one of the most common methods to fabricate Bi 2 Te 3 nanostructure in thermoelectric applications. But the development of device-quality material has been a challenging task for the researchers, yet. For this reason, this paper provides a review of current research activities on Bi 2 Te 3 nanostructure growth by several methods and its characterization through theoretical and analytical aspects. Moreover, the paper handles a systematic and intensive research work to develop and understand the materials in nanostructure forms.
Metal Nanoinclusions (Bi and Ag) in Bi2Te3 for Enhanced Thermoelectric Applications
MRS Proceedings, 2010
Metal nanoinclusions inside the bulk thermoelectric matrix have the potential to increase the power factor and reduce the lattice thermal conductivity. We have synthesized Bi2-xTe3+x (x=0, 0.05)compositions, to achieve better tenability in Seebeck and electrical conductivity. In this matrix phase, different volume fractions of Bi metal nanoinclusions were incorporated and its effect on thermoelectric properties is discussed. Ag metal nanoinclusions were incorporated into Bi2Te3(2:3) composition, and its effect on power factor is discussed here.
Journal of Materials …, 2012
Bismuth telluride (Bi 2 Te 3 ) is the best-known commercially used thermoelectric material in the bulk form for cooling and power generation applications at ambient temperature. However, its dimensionless figure-of-merit-ZT around 1 limits the large-scale industrial applications. Recent studies indicate that nanostructuring can enhance ZT while keeping the material form of bulk by employing an advanced synthetic process accompanied with novel consolidation techniques. Here, we report on bulk nanostructured (NS) undoped Bi 2 Te 3 prepared via a promising chemical synthetic route. Spark plasma sintering has been employed for compaction and sintering of Bi 2 Te 3 nanopowders, resulting in very high densification (>97%) while preserving the nanostructure. The average grain size of the final compacts was obtained as 90 AE 5 nm as calculated from electron micrographs. Evaluation of transport properties showed enhanced Seebeck coefficient (À120 mV K À1 ) and electrical conductivity compared to the literature state-of-the-art (30% enhanced power factor), especially in the low temperature range. An improved ZT for NS bulk undoped Bi 2 Te 3 is achieved with a peak value of $1.1 at 340 K.
Journal of Electronic Materials, 2009
Thermoelectric compounds based on doped bismuth telluride and its alloys have recently attracted increasing interest. Due to their structural features they show increased values of the thermoelectric figure of merit (ZT). A promising approach to improve the thermoelectric properties is to manufacture nanocomposite materials exhibiting lower thermal conductivities and higher ZT. The ZT value of compounds can be shifted reasonably to higher values (>1) by alloying with IV-Te materials and adequate preparation methods to form stable nanocomposites. The influence of PbTe and Sn on the thermoelectric properties is studied as a function of concentration and preparation methods. Melt spinning and spark plasma sintering were applied to form nanocomposite materials that were mechanically and thermodynamically stable for applications in thermoelectric devices. The structural properties are discussed based on analysis by transmission electron microscopy and x-ray diffraction.
Journal of Materials Chemistry, 2012
The study of the thermoelectric performance of electrodeposited Pt nanoparticles-bismuth telluride nanocomposites (Pt/Bi 2 Te 3) film is presented in this paper. An electrolyte solution containing nitric acid and bismuth-telluride ions was mixed with various concentrations of Pt nanoparticles. 1.0 wt% to 1.9 wt% of Pt nanoparticles in the composites have been successfully synthesized and their thermoelectric performances were investigated. It is found that at 1.9% of Pt nanoparticles weight percentage in the Bi 2 Te 3 matrix, the power factor increased to 1.8 Â 10 À3 W m À1 K À2 which is more than twice higher than that of an electrodeposited pure Bi 2 Te 3 film. Meanwhile, the evaluation on thermal conductivity of the composite shows promising improvement, which is more than 40% reduction as compared to the Bi 2 Te 3 film. As a result, a higher ZT value of 0.61 is obtained for the Pt (1.9 wt%)/Bi 2 Te 3 film which is approximately more than triple of ZT of the electrodeposited Bi 2 Te 3 film at room temperature.
Journal of Alloys and Compounds, 2006
Effect of Ag-doping on thermoelectric properties of n-type Bi 2 (Te 0.94 ,Se 0.06 ) 3 is studied. Bulk Bi 2 (Te 0.94 ,Se 0.06 ) 3 sample with single solid solution phase and high relative density (over 95%) is obtained by mechanical alloying and subsequent hot press sintering. The as-sintered sample has a microstructure of randomly distributed plate grains and its size is about 1 m. A V-shaped variation for the electrical properties with Ag doping is found which corresponds to different Ag atomic position in lattice among the doping range studied. A maximum figure of merit of about 1.7 × 10 −3 /K is achieved.
Development of Bismuth Telluride Nanostructure Pellet for Thermoelectric Applications
Hittite Journal of Science & Engineering
T he bismuth telluride (Bi 2 Te 3) is an efficient thermoelectric (TE) semiconductor type material. When the post transition metal elements of bismuth (Bi) is alloyed with a metalloid non-metal elements of tellurium (Te) then it makes a compound semiconductor material, Bi 2 Te 3. An acceptable TE material is indicated by large density and mobility of charge carriers, at the coinciding by the low thermal conductivity and high electrical conductivity. Another attractive aspect is that the efficient energy conversion adaptability of a TE material is performed by the extensive dimensionless figure of merit: ZT = (S 2 σT)/K, where S is the Seebeck coefficient, σ is the electrical conductivity, K is the thermal conductivity and T is the temperature. Nowadays, Bi 2 Te 3 nanostructure has a great deal of interest in thermoelectric applications such as thermoelectric heating and cooling, thermoelectric generators and portable power supply [1-10]. Recent studies suggest that Bi 2 Te 3 material usage in nanostructure form generates the higher ZT (from 0.62 to 1.13) values [11-17].
ACS Applied Materials & Interfaces, 2017
Thermoelectric materials are of utmost significance for conversion of heat flux into electrical power in the low-power regime. Their conversion efficiency depends strongly on the microstructure. AgSbTe 2-based compounds are high-efficiency thermoelectric materials suitable for the mid-temperature range. Herein, we explore a Ag 16.7 Sb 30 Te 53.3 alloy (at. %) subjected to heat treatments at 380 °C for different durations aimed at nucleation and coarsening of Sb 2 Te 3-precipitates. To characterize the Sb 2 Te 3-precipitation, we use a set of methods
In this work, it is demonstrated that a higher electrical conductivity can be obtained when Ag atoms, as a transition metal, replaces Bi atoms in the n-type Bi 2-x Ag x Se 3 system. As a result of differences in the atomic mass and size between Ag and Bi, larger Seebeck coefficient is obtained. The concerned Bi 2-x Ag x Se 3 alloys were prepared by melting in high temperature. Identifications of the microstructure and surface morphology were carried out via X-ray diffraction (XRD) analysis and scanning electron microscope (SEM) attached with the energy dispersive x-ray (EDX) unit. All samples are polycrystalline. Seebeck coefficient, electrical and thermal conductivities were measured over the temperature range 300 e473K. Notable enhancement in the electrical conductivity is obtained. The thermoelectric power factor is calculated showing its maximum value at 260 mW/mK 2. High electrical conductivity and high Seebeck coefficient of some of the doped alloys resulted in a promising figure of merit (ZT). The largest ZT is calculated at 0.23 at 473K for the Bi 1.8 Ag 0.20 Se 3 sample.