Alloys and Compounds for Thermoelectric and Solar Cell Applications IX: Session II
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Alloy Phases Committee
Program Organizers: Hsin-Jay Wu, National Chiao Tung University; Sinn-wen Chen, National Tsing Hua University; Franck Gascoin, CNRS Crismat Unicaen; Philippe Jund, Montpellier University; Yoshisato Kimura, Tokyo Institute of Technology; Lan Li, Boise State University; Takao Mori, National Institute For Materials Science; Tiejun Zhu, Zhejiang University; Alexandra Zevalkink, Michigan State University; Wan-Ting Chiu, Tokyo Institute of Technology
Monday 2:00 PM
March 15, 2021
Room: RM 21
Location: TMS2021 Virtual
Session Chair: Yi-Fen Tsai, National Yang Ming Chiao Tung University; Wan-Ting Yen, National Chiao Tung University
2:00 PM Invited
Challenges and Opportunities of Flexible Thermoelectric Devices Based on Printing Technology: Chien-Neng Liao1; 1National Tsing Hua University
Recent prosperous thermoelectric research activities have made a significant progress in improving performance of thermoelectric materials. Traditional bulk-type thermoelectric modules suffer from high material loss during cutting and grinding, while thin-film type thermoelectric modules high fraction of electrical/thermal contact resistance and high processing cost. Thick-film modules made by screen printing or dispenser printing technologies have found appealing applications in the field of self-powered wireless network sensing and long-term biological monitoring due to their cost-effective fabrication process. The current printed thermoelements usually exhibit worse electrical conductivity and low thermoelectric power factor than their bulk counterparts. This talk intends to introduce the research and development efforts of printing thick-film modules, especially focused on flexible thermoelectric devices. The major technical challenges and breakthroughs for the development of printing-based thermoelectric devices are presented, including thermoelement processing, device configuration and heat sink/source arrangements. Finally, some potential applications for low-power flexible thermoelectric devices are introduced.
2:20 PM Invited
Comparing Thermoelectricity of Bulk and Thin Film Heusler Alloys: Ernst Bauer1; B. Hinterleitner1; A. Riss1; M. Parzer1; F. Garmroudi1; T. Mori2; X. Chen3; 1Technische Universität Wien; 2NIMS; 3Shenyang National Laboratory for Materials Science
Although full Heusler systems exhibit superior thermoelectric power factors, large thermal conductivities prevent from figure of merit values ZT > 1. A recent study [1], however, showed that ZT >> 1 has been observed for such materials if prepared as thin film, deposited on a Si wafer. The aim of the present work is a systematic comparison and critical evaluation of electronic and thermal transport in both thin films and bulk samples, based on electrical resistivity data, on magnetoresistance and on the Hall effect, obtained in a broad range of temperatures and magnetic fields (from 4 to 800 K and up to 12 T), in the context of density functional theory results. The role of off-stoichiometry in these Heusler systems is highlighted, too. Research supported by JST under the program CREST and MIRAI. [1] B. Hinterleitner et al., Nature 576 (7785), 85-90, 2019.
2:40 PM
Optimizing Thermoelectric Properties of Few-layer Transition Metal Dichalcogenides: Tianhui Zhu1; Mona Zebarjadi1; 1University of Virginia
Two-dimensional transition metal dichalcogenides (TMDCs) have relatively good electrical conductivity and relatively low thermal conductivity among all two-dimensional materials, which indicates their potential for thermoelectric energy conversion applications. The existing studies on of few-layer TMDCs, such as MoS2 and WSe2, have shown improved thermoelectric performances compared to their bulk and their peak thermoelectric power factor can exceed that of a commercial bulk Bi2Te3 [1]. In this study, we fabricate devices from mechanically exfoliated TMDCs (for example MoTe2) and aim to optimize their thermoelectric properties by varying parameters, such as temperatures, back gate voltages and substrates. [1] J. Appl. Phys. 120, 134305 (2016); Phys. Rev. B 95, 115407 (2017); Nano Lett. 16, 2061 (2016).
3:00 PM
Solid-state thermionic Devices: Effect of Asymmetry on the Device Performance: Md Golam Rosul1; Mona Zebarjadi1; 1University of Virginia
Solid-state thermionic (SSTI) devices are metal-semiconductor-metal structures with operation principles similar to thermoelectric devices. The semiconducting layer thickness is smaller than the mean-free-path ensuring ballistic transport and is larger than several atomic layers to suppress the tunneling current and ensure thermionic transport. Van der Waals (vdW) heterostructures are considered good candidates as the semiconductor layer due to their weak thermal conduction in the cross-plane direction and ability to tune barrier height by changing the number of layers. The maximum theoretical zT value of 3 is predicted for these structures. Here, we study the effect of structural asymmetry on the performance of vdW based SSTI devices. Such structural asymmetry is a common feature in vacuum-state devices but has not been investigated in SSTIs. In these devices 3-5 layers of two-dimensional transition metal dichalcogenides are sandwiched between two dissimilar metallic electrodes and the effect of asymmetry on the device performance is investigated.
3:20 PM
Interfacial Reaction in Ag/Se, Ag/Te, Ag2Te/Se and Ag2Te/Se-30at.%Te Couples and Their Related Phase Diagram: Yohanes Hutabalian1; Sinn-wen Chen1; 1National Tsing Hua University
Ag-Se-Te is an important material system for thermoelectric applications. Various compounds in this system, such as Ag2Te, Ag2Se and Ag2Se1-xTex are promising thermoelectric materials. The reaction couples of Ag/Te, Ag/Se, Ag2Te/Se and Ag2Te/Se-30at.%Te at 350oC are prepared and examined. In all the couples, the diffusion rate of Ag is much greater than those of Se and Te. Ag2Te and Ag5Te phases are formed in the Ag/Te couple and the reaction diffusion is very fast. The isothermal sections of Ag-Se-Te ternary system at 400oC, 350℃, 300oC and 250oC are determined. No ternary compound is observed and the Ag2Te-Ag2Se is a continuous solid solution phase, Ag2(Se,Te). The related reaction paths and mass balances of the reaction couples are well explained using the determined phase diagram.
3:40 PM
Thermoelectric Cell Setup for Heat Recovery in Industrial Chimneys: Manuela Castañeda Montoya1; Andrés Amell Arrieta1; Henry Colorado1; 1Universidad de Antioquia
There is an increasing pressure for reducing pollution and develop process following circular economy practices, which is moving many countries to support more the development for alternative energies and technologies that reduce the adverse environmental impacts. This investigation presents an experimental configuration with thermoelectric cells for heat recovery for chimneys. Different external and internal parameters were analyzed in order to determine the best efficiency and the greatest recovery of residual heat from the processes. "The authors gratefully acknowledge the financial support provided by the Colombia Scientific Program within the framework of the call Ecosistema Científico (Contract No. FP44842- 218-2018).
4:00 PM Invited
Impact of Surface Engineering in Silicon Film Thermoelectrics: Masahiro Nomura1; 1The University of Tokyo
Phonon backscattering at the engineered surface is also an effective method to reduce thermal conductivity as well as alloy and boundary scatterings to develop highly efficient thermoelectric material. Deposition of an ultra-thin Al layer (5-10 angstrom) forms Al/Si alloys, and the nanodots backscatter phonons strongly but not for charge carriers, which resulted in a 40% increase in ZT and power density at room temperature. We also introduce the impact of nanopillars formed on the surface of a thin Si film, which can be used for the fabrication of low-cost and large-area planar type thermoelectric power generators.
4:20 PM Invited
Developing Thermoelectric Thin Films and Modules for IoT Energy Harvesting: Takao Mori1; 1National Institute for Materials Science
There is an urgent need to develop technologies which can autonomously power IoT sensors and devices, such as thermoelectric thin films [1]. We have developed original materials in sulfides, skutterudites, Heuslers [2], and with collaborators, promising thermoelectric thin films have been fabricated from related materials [3]. In addition to latest developments of these, I will also present advancements made in thin film thermal conductivity measurements, enabling site selective measurements and separation of the interfacial thermal resistance [3,4], together with applicative considerations for power generation modules. [1] MRS Bulletin, 43, 176 (2018), Sci. Tech. Adv. Mater., 19, 836 (2018). [2] Nano Energy, 31 152 (2017), Sci. Adv., 5, eaat5935 (2019). [3] RSC Advances, 10, 21129 (2020), Nature, 576, 85 (2019).[4] J. Phys. Chem. C 122, 27127 (2018), Phys. Rev. B., 99, 085422 (2019).
4:40 PM Invited
Thermomagnetic Transport in 2D Layered Topological Materials: Mona Zebarjadi1; Md. Sabbir Akhanda1; Emad Rezaei1; Md. Golam Rosul1; Keivan Esfarjani1; Albert Davydov2; Sergiy Krylyuk2; 1University of Virginia; 2NIST
Thermomagnetic transport is unique and perplexed as it includes the interaction of electrons, holes, and phonons with external magnetic, electric, and temperature gradient fields. The magnetic field allows separation of the electrons and holes and allows decoupling of charge and heat. Thermomagnetic power generation and cooling can replace the thermoelectric ones at low temperatures (near ambient and below). Anisotropic materials with low thermal conductivity in one direction and large electrical conductivity in a perpendicular direction are ideal for thermomagnetic applications. Hence, 2D layered materials are of interest. Topological materials with large carrier mobility and bipolar conduction further show promise for thermomagnetic applications. In this talk, we discuss our recent study of several anisotropic topological materials including Bi2Te3, 2H-NbSe2, and MoTe2. We report measurements of thermoelectric properties as well as magneto-Seebeck and Nernst coefficient in these materials and explain the results using first-principles calculations as well as simplified and phenomenological models.
5:00 PM Invited
Cu-Sn Based Thiospinel Compounds: Insight of Alternative Route for Developing Thermoelectrics Thiospinel Compounds?: Cedric Bourges1; 1Nims
In the present study, we have reported for the first time the thermoelectric (TE) properties of a series of Cu-Sn based thiospinel compounds by screening a variety of transition elements as a potential substituent at the Sn-site with the designed composition CuM1+xSn1-xS4 (M = Transition metal), besides an in-depth structural, electronic band structure investigation and a brief outlook at their magnetic properties. The optimized synthesis and processing conditions reported here enabled to realize highly densified and mostly pure (single phase) compounds with both p- and n-type compounds. We highlighted that Sn-based thiospinel are attractive by their reduce thermal transport (klatt ≈ 1 W/m.K@673K) compare with others TE thiospinel reported. Finally, the composition with M = Cr appeared as the most attractive TE properties due to the simultaneous increase of Seebeck coefficient and electrical conductivity with increasing temperature, thus resulting in a respectable power factor (PF ≈ 0.35 mW/m.K2@673K).
5:20 PM
First-principles Calculation of Nernst Coefficient and Magneto-Seebeck: Emad Rezaei1; Md Sabbir Akhanda1; Keivan Esfarjani1; Mona Zebarjadi1; 1University of Virginia
In the presence of a temperature gradient and an orthogonal magnetic field, a transverse thermomagnetic voltage, the so-called Nernst voltage develops. Semimetals are known to be good candidates for thermomagnetic transport due to their bipolar nature of transport and their unique topological properties. Herein, we study the Nernst signal and the magneto-Seebeck coefficient of several semimetals in weak magnetic fields using first-principles calculations as well as phenomenological models. Theoretical predictions are compared and their validity is tested by comparing the results with the experiment in a wide temperature range and for different carrier concentrations.