Fabrication Of Thermoelectric Materials Research Articles

Advances in printing techniques for thermoelectric materials and devices

Thermoelectric materials and devices have garnered significant attention in recent years due to their potential for converting waste heat into usable electricity, opening new avenues for sustainable energy harvesting. As research in the field of thermoelectric materials and devices continues to grow, so does the need for efficient and scalable fabrication methods. Among various fabrication techniques, printing methods have emerged as promising approaches to producing thermoelectric materials and devices, offering advantages such as low cost, high throughput, and design flexibility. Here, we overview the recent advances in printing methods for the fabrication of thermoelectric materials and devices. We discuss the key principles, challenges, and opportunities associated with various printing techniques, including screen printing, inkjet printing, and 3D printing, with a focus on their applications in thermoelectric materials and devices. Furthermore, we highlight the progress made in optimizing the printing parameters, ink formulations, and post-processing methods to enhance the thermoelectric performance of printed materials and devices. Finally, we provide insights into the prospects and potential research directions in the field of printing methods for thermoelectric materials and devices. This review aims to provide a comprehensive overview of the state-of-the-art printing techniques for thermoelectric materials and devices and to serve as a reference for researchers and practitioners working in this rapidly growing field.

Thermoelectric properties of Sm-doped BiCuSeO oxyselenides fabricated by two-step reactive sintering

Among layered oxygen-containing compounds, BiCuSeO is one of the most promising candidates for thermoelectric applications due to its intrinsically low thermal conductivity and good thermal stability. However, the rather poor electrical conductivity of pristine BiCuSeO hinders its potential. Further enhancement of the thermoelectric performance by single doping at Bi site is limited mainly due to dramatic decrease of carrier mobility. Thus, new strategies, such as dual doping or doping with variable-valence elements seem to be promising. Along with that, the development of a fast and scalable synthesis route is essential for the industrial-scale fabrication of thermoelectric materials. Hence, in this paper, Bi 1– x Sm x CuSeO samples (0 ≤ x ≤ 0.08) have been synthesized with a simple and scalable reactive sintering process. For comparison, Bi 1– x Sm x CuSeO oxyselenides were also obtained by the conventional solid-state route. Our results highlight that, Sm for Bi substitution increases the electrical conductivity by 1.5–2 times and decreases the Seebeck coefficient by ~1.4 times at 873 K for both series. Overall, considering the increase of lattice thermal conductivity upon doping and not optimized power factor, the figure of merit z T is reducing upon doping. • Sm-doped BiCuSeO oxyselenides fabricated by reactive sintering. • Sm doping leads to an increase of σ from 39 Ω –1 cm –1 to ~55 Ω –1 cm –1 at 873 K. • Quality factor is reduced upon Sm doping due to increase in κ and decrease of μ w .

CALPHAD as a powerful technique for design and fabrication of thermoelectric materials

This review focuses on the guiding role of CALculation of PHAse Diagram (CALPHAD): providing comprehensive thermodynamic and kinetic information to bridge the theoretical design and experimental synthesis of TE materials.

A new rapid synthesis of thermoelectric Sb2Te3 ingots using selective laser melting 3D printing

The conventional synthesis and forming process methods of commercialized thermoelectric materials and thermoelectric devices are energy and time consuming. Fortunately, advanced 3D printing techniques enable simplification for the rapid fabrication of thermoelectric materials. Herein, we report a new synthesis method of Sb2Te3 by selective laser melting (SLM) printing technique. A mixture of individual elemental powder of Sb and Te serves as starting materials for the SLM process. The effect of the high laser energy density on the synthesized Sb2Te3 structure and thermoelectric performance is also investigated, and the optimal process parameters are determined. The phase transition process for the Sb/Te powder during SLM is imitated by performing a thermogravimetric analysis (TGA) simultaneously. The power factor of the ingot prepared by SLM increases up to 19 μW/(cm K2) at 50 °C. These results indicate that SLM can effectively produce Sb2Te3-based materials. This work opens a new route for the design and synthesis of thermoelectric materials and corresponding devices.

Simulation of SPS Process for Fabrication of Thermoelectric Materials with Predicted Properties

Spark plasma sintering (SPS) is a promising method for fabrication of thermoelectric materials. The electric and thermal fields in the SPS process have been simulated by using the finite element method to model an SPS-511S experimental setup. Investigation of thermoelectric materials based on Bi2Te3 solid solutions revealed that the temperature measured close to the sample during application of the electric current could be reproduced by the simulation. Modification of the compression mold configuration could be used to alter the electric and thermal conditions, adjust the Joule heat released in the setup elements, and create a gradient temperature field during the SPS process. The temperature–time dependence in the sample was also studied, revealing that the temperature difference along the vertical axis may reach hundreds of degrees. Prediction of the sintering temperature in each layer may allow further prediction of the thermoelectric properties of the sample. More accurate modifications of the SPS process based on such computer simulations may help to form structures with macroscopically inhomogeneous and functionally graded legs.

Production Methods of Thermoelectric Materials and their Main Characteristics

This paper is intended for the analysis of the fabrication of Thermoelectric Materials with emphasis on the use of Powder Technology including the use of Powder Technology. Main characteristics of them are considered. The recycling of thermoelectric material pieces is shown.

Super-fast preparation of Nd-filled p-type skutterudite compounds with enhanced thermoelectric properties

P-type filled skutterudite materials have been gained considerable research interest in recent years due to their promising thermoelectric power generation applications at intermediate temperature. Herein, we systematically investigated the influence of Nd filling on the thermoelectric properties of NdxFe2Co2Sb12 (x=0.4, 0.5 0.6, 0.7 and 0.8). Nd-filled skutterudites are synthesized using a simple and time-saving induction melt spinning technique followed by spark plasma sintering. The results show that Nd-filling leads to the significant reduction in the lattice thermal conductivity and enhancement of power factor over the entire temperature range. The most marked reduction in the lattice thermal conductivity is achieved with the value of 0.76W/mK for x=0.7 sample, due to strengthened phonon scattering. Meanwhile, the highest ZT=0.98 is attained at 740K for Nd0.7Fe2Co2Sb12. The rapid synthesis procedure provides an effective pathway for the fabrication of thermoelectric materials with high performance.

Air-tolerant Fabrication and Enhanced Thermoelectric Performance of n-Type Single-walled Carbon Nanotubes Encapsulating 1,1'-Bis(diphenylphosphino)ferrocene.

The thermally-triggered n-type doping of single-walled carbon nanotubes is demonstrated using 1,1'-bis(diphenylphosphino)ferrocene, a novel n-type dopant. Through a simple thermal vacuum process, the phosphine compounds are moderately encapsulated inside single-walled carbon nanotubes. The encapsulation into SWNTs is carefully characterized using Raman/X-ray spectroscopy and transmission electron microscopy. This easy-to-handle doping with air-stable precursors for n-type SWNTs enables the large-scale fabrication of thermoelectric materials showing an excellent power factor exceeding approximately 240 μW mK(-2) .

Fabrication of thermoelectric materials – thermal stability and repeatability of achieved efficiencies

Thermoelectric properties of metastable metal chalcogenides degrade with thermal cycling.

Fabrication and Characterization of Nanostructured Thermoelectric Materials and Devices

ABSTRACTWe present results of modeling and experimental characterization of thermoelectric (TE) materials built on new fabrication principles, involving the coating of three-dimensionally structured quantum well super-lattice substrates with PbTe/PbSe. A new system for wafer-scale electrochemical deposition of such structures was specifically developed and will be described in this paper. Scanning electron microscopy (SEM) was used to measure film thickness and electron diffraction spectroscopy (EDS) was used to determine film material concentration. By adjusting deposition parameters, we were able to build stoichiometric PbSe, PbTe and stacked PbSe/PbTe super-lattice films on planar and pre-structured surfaces. The films were thermoelectrically modelled using COMSOL and then characterized using an infrared Seebeck effect measurement system which measured surface heating of the film while measuring the voltage associated with the temperature gradient. We report advances in the design and fabrication of TE materials which improve cost-effectiveness and TE efficiency.

Polyaniline Hybrid with Inverse Opal Structure for Fabrication of Thermoelectric Materials

The colloidal crystal template or opal with a closed-packed face centered cubic (fcc) lattice was prepared from monodisperse polystyrene (PS) microspheres by gravity sedimentation, and it was used for the fabrication of polyaniline hybrid with inverse opal structure. The template provided void space for the infiltration of Bi2Te3 and monomer that was then in situ polymerized to polyaniline. The opal composite was then soaked in toluene for completely removing PS microspheres to form porous polyaniline hybrid with inverse opal structure. The PS microspheres were replaced by air microspheres, which interconnected each other through the windows on the polyaniline hybrid wall. Both the wall and the air void constitute continuous phases. The polyaniline hybrid with inverse opal structure was observed with scanning electronic microscopy.

Use of Electrochemical Etching to Produce Doped Phenylacetylene Functionalized Particles and Their Thermal Stability

Silicon is an attractive material for the fabrication of thermoelectric materials. Previously, it was reported that phenylacetylene capped silicon nanoparticles (PA-SiNPs), which were synthesized from micelle reduction, displayed a ZT of up to 0.6 at ambient temperature. The major contributing factor to this result was the material’s low thermal conductivity. However, this material also displayed a low electrical conductivity compared to other thermoelectric materials. This is contributed to, in part, by low charge carrier concentration, which is difficult to control in micelle reduction-based methods. Top–down methods allow control of the carrier concentration as the material is doped prior to the breaking down of the material. PA-SiNPs were synthesized using electrochemical etching followed by functionalization. These particles were then analyzed with transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, thermo-gravimetric analysis (TGA), and differential scanning calorimetry (DSC). The DSC and TGA trace were compared to those of PA-SiNPs synthesized by micelle reduction to show that the thermal stability range is much higher in the particles synthesized from the top–down method giving them a wider range of potential thermoelectric applications.

Measurement of Thermoelectric Properties of Phenylacetylene-Capped Silicon Nanoparticles and Their Potential in Fabrication of Thermoelectric Materials

Silicon is a highly attractive material for the fabrication of thermoelectric materials. Nanostructured silicon materials, such as silicon nanowires (SiNWs), show great potential as they show low thermal conductivities due to efficient phonon scattering but similar electrical conductivities to bulk silicon. Silicon nanoparticles (SiNPs) are easier to synthesize and show a greater number of surface defects, which suggests that more efficient phonon scattering can be achieved, but these materials also show low electrical conductivity due to defects within the materials unless pressed at high temperatures (1100°C). Conjugated capping layers show the potential to bridge these defects, giving higher conductivity without the need for this process. Phenylacetylene-capped SiNPs are synthesized via the micelle reduction method and pressed into a pellet. Measurements of the electrical conductivity, Seebeck coefficient, and thermal conductivity were taken. The results show that the material produced from these particles shows a relatively high Seebeck coefficient (3228.84 μV K−1) which would have a positive effect on the figure of merit (ZT). A respectable electrical conductivity (18.1 S m−1) and a low thermal conductivity (0.1 W m−1 K−1) confirm the potential of using conjugated molecules as a way of cross-linking between nanoparticles in a bulk material fabricated from SiNPs. These results give a figure of merit of 0.57, which is comparable to better established thermoelectric materials.

온수를 이용한 열전발전기에서 유량변화에 따른 발전 특성

The objective of this study is to develop a thermoelectric generation system which converts unused energy from close-at-hand sources such as garbage incineration heat and industrial exhaust etc. into electricity. This paper presents applicability of a commercially available thermoelectric generator for waster heat recovery. The test facility consists of water heater, pump, thermoelectric module and aluminium tubes and hot and cold water is used as heat source and sink fluids. It is shown that the three components of thermoelectric research exist in manufacturing a thermoelectric generator. The first component is fabrication of thermoelectric materials, the second is manufacturing of thermoelectric generator with 32 thermoelectric modules. The last one is characteristic measuring of thermoelectric generator with 32 thermoelectric modules of two types, cooling and power purpose. It was found that the rate of cold and hot water is 25 and 37 liter per minute and the maximum power of thermoelectric generator is 28Watts and its efficiency is 1.04%.<br/>

Effects of Hydrogen Reduction in Microstructure, Mechanical and Thermoelectric Properties of Gas Atomized &amp;lt;italic&amp;gt;n&amp;lt;/italic&amp;gt;-type Bi2Te2.7 Se0.3 Material

&lt;p&gt;The recent rise in applications of thermoelectric materials has attracted interest in studies toward the fabrication of thermoelectric materials using mass production techniques. In this study, we successfully fabricate &lt;italic&gt;n&lt;/italic&gt;-type Bi&lt;sub&gt;2&lt;/sub&gt;Te&lt;sub&gt;2.7&lt;/sub&gt;Se&lt;sub&gt;0.3&lt;/sub&gt; material by a combination of mass production powder metallurgy techniques, gas atomization, and spark plasma sintering. In addition, to examine the effects of hydrogen reduction in the microstructure, the thermoelectric and mechanical properties are measured and analyzed. Here, almost 60% of the oxygen content of the powder are eliminated after hydrogen reduction for 4 h at 360°C. Micrographs of the powder show that the reduced powder had a comparatively clean surface and larger grain sizes than unreduced powder. The density of the consolidated bulk using as-atomized powder and reduced atomized powder exceeds 99%. The thermoelectric power factor of the sample prepared by reduction of powder is 20% better than that of the sample prepared using unreduced powder.&lt;/p&gt;

Fabrication of thermoelectric materials by rotary swaging

A powder metallurgy process for fabricating thermoelectric materials into tubular elements by rotary swaging is described. The relationships investigated in these studies were: 1. (1) The effects of powder preparation procedure on the thermoelectric properties of the swaged and sintered material. 2. (2) The effect of sintering temperature and time on the properties. 3. (3) The effect of density of loading of the materials in the sheathing on the required reduction of area in swaging. Results of swaging studies on n-type and p-type PbTe and Bi x Ge 1− x Te are reported. Results are also reported on the measurements of electrical resistivity, Seebeck coefficient and thermal conductivity of n-type and p-type PbTe swaged annular elements. Studies have also been made on the compatibility of lead telluride with a variety of cladding materials.