Article
Materials Science, Multidisciplinary
Kumar Saurabh, Vineet Kumar Pandey, Ankit Kumar, Prasenjit Ghosh, Surjeet Singh
Summary: Half-Heusler alloys have the potential to be used as mid-to-high temperature range thermoelectric materials due to their high power factor and solid structural stability. However, the high lattice thermal conductivity of these materials hinders their practical applications. In this study, we investigate the effects of excess Nb and Sn doping in defective half-Heuslers and show that Sn doping allows for a finer control of carrier concentration and a higher concentration of Nb in the structure. The optimized carrier concentration and changes in the band structure lead to suppression of bipolarity and enhancement of thermopower at high temperatures, resulting in a high zT value exceeding 1 at 1100 K. This value is approximately 15% higher than the highest zT previously reported.
MATERIALS TODAY PHYSICS
(2023)
Review
Chemistry, Multidisciplinary
Nagendra S. Chauhan, Yuzuru Miyazaki
Summary: This review summarizes the importance and optimization pathways of iron-based half-Heusler alloys in thermoelectric conversion, including materials synthesis, electronic transport mechanisms, and microstructural approaches. Through the analysis and comparison using a parametric framework, the high power factors exhibited by these alloys are well understood. Additionally, density functional theory-based calculations are used to analyze the electronic structures of the half-Heusler alloys, explaining their favorable conduction and electrical transport properties. Finally, the correlations between processing, structure, and properties are discussed, providing guidance for developing efficient iron-based half-Heusler thermoelectric materials.
Article
Chemistry, Physical
Amin Nozariasbmarz, Udara Saparamadu, Wenjie Li, Han Byul Kang, Carter Dettor, Hangtian Zhu, Bed Poudel, Shashank Priya
Summary: This study demonstrates a TEG fabrication process that can achieve high electrical conversion efficiency at high temperatures by reducing thermal and electrical resistances between metal electrodes and TE legs, improving TEG performance and stability.
JOURNAL OF POWER SOURCES
(2021)
Article
Chemistry, Inorganic & Nuclear
Feng Gao, Ying Lei, Yu Li, Jin Qiu, Chao Yong, Nan Wang, Guangyuan Song, Huaichuan Hu
Summary: TiNiSn1-xSbx thermoelectric bulks were fabricated using microwave synthesis combined with spark plasma sintering and annealing process. The high density of the samples was confirmed through physical phase analysis and microstructure characterization. Antimony doping and annealing process significantly improved the electrical properties of the TiNiSn-based materials and maintained low lattice thermal conductivity. TiNiSn0.965Sb0.035 achieved a maximum power factor of 3125.9 mu Wm(-1)K(-2) at 873 K and a total thermal conductivity of 4.2-4.7 W m(-1)K(-1), with a maximum ZT value of 0.57, which is 86% higher than that of the undoped sample.
JOURNAL OF SOLID STATE CHEMISTRY
(2023)
Article
Physics, Applied
Kaiyang Xia, Chaoliang Hu, Chenguang Fu, Xinbing Zhao, Tiejun Zhu
Summary: Half-Heusler compounds with 18 valence electrons are considered promising high-temperature thermoelectric materials, while nominal 19-electron compounds have gained popularity due to their unexpected high performance. The focus is now on the discovery and challenges of cation-deficient 19-electron half-Heusler compounds with vacancy-related short-range order, offering insights into defect-tailored thermoelectric properties.
APPLIED PHYSICS LETTERS
(2021)
Article
Materials Science, Ceramics
Hyerin Jeong, Samuel Kimani Kihoi, Joseph Ngugi Kahiu, Hyunji Kim, Juhee Ryu, Kyu Hyoung Lee, Seonghoon Yi, Ho Seong Lee
Summary: The Nb1-xTixFe1.02Sb half-Heusler thermoelectric materials were synthesized by arc melting and subsequent spark plasma sintering (SPS). Doping Ti at Nb-site results in high power factor and reduced lattice thermal conductivity. Phonon scattering was enhanced at alternating interphase boundaries, leading to improved thermoelectric performance with a peak ZT of -0.81 at 973 K.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Multidisciplinary Sciences
Ruiheng Liu, Yunfei Xing, Jincheng Liao, Xugui Xia, Chao Wang, Chenxi Zhu, Fangfang Xu, Zhi-Gang Chen, Lidong Chen, Jian Huang, Shengqiang Bai
Summary: The researchers developed a thermodynamic strategy to improve electrode bonding in half-Heusler devices, resulting in high thermal stability and ideal ohmic contact at high temperatures. This design strategy enables the devices to work stably and achieve significantly higher energy conversion efficiencies.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Wenjie Li, Amin Nozariasbmarz, Ravi Anant Kishore, Han Byul Kang, Carter Dettor, Hangtian Zhu, Bed Poudel, Shashank Priya
Summary: Thermoelectric generators utilizing the Seebeck effect present a promising solution for waste heat recovery. Half-Heusler alloys are leading candidates for medium- to high-temperature power generation applications, but face challenges in practical implementation. A new conformal architecture design provides a breakthrough for medium- to high-temperature TEG technology, offering higher performance compared to traditional TEG devices.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Chemistry, Multidisciplinary
Junhong Wei, Yongliang Guo, Guangtao Wang
Summary: In this study, the full potential linearization enhanced plane wave method in density functional theory is used to investigate the structure, mechanical, and thermoelectric properties of half-Heusler compounds RhBiX (X = Ti, Zr, Hf) for the first time. The results show that RhBiTi and RhBiZr are indirect semiconductors with bandgap energies of 0.89 and 1.06 eV, respectively, while RhBiHf is a direct bandgap semiconductor with a bandgap energy of 0.33 eV. The thermoelectric parameters and the maximum ZT values are also studied, showing that RhBiX (X = Ti, Zr, Hf) alloy has great potential as a thermoelectric material.
Article
Crystallography
Paul O. Adebambo, Bamidele I. Adetunji, Oghenekevwe T. Uto, Stephane Kenmoe, Gboyega A. Adebayo
Summary: The properties of the VIrSi half-Heulser alloy were investigated using density functional theory. The results showed that this alloy has high Seebeck coefficient and power factor, making it suitable for thermoelectric applications.
Article
Chemistry, Physical
Zhuoyang Ti, Shuping Guo, Xuemei Zhang, Jingyu Li, Yongsheng Zhang
Summary: Researchers constructed novel HH compounds by mixing 17-electron and 19-electron systems, achieving semiconducting behavior in thermoelectric materials. Two thermodynamically stable compounds were predicted with higher band degeneracy and lower thermal conductivity compared to the original compound.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Article
Physics, Multidisciplinary
Nisha, Hardev S. Saini, Sunita Srivastava, Manish K. Kashyap
Summary: The systematic investigation of the electronic and thermoelectric properties of the half-Heusler compound LuPdBi at different hydrostatic pressures showed that these properties can be significantly modified by modulating hydrostatic pressure, leading to improved ZT values. The highest ZT value of around 0.35 was achieved under a hydrostatic pressure of 18.18 GPa in the case of n-type doping. This recognition of high thermoelectric performance under different hydrostatic pressures in LuPdBi may open up new avenues for further research on similar topological thermoelectric materials.
Article
Chemistry, Physical
A. Diack-Rasselio, O. Rouleau, L. Coulomb, L. Georgeton, M. Beaudhuin, J. C. Crivello, E. Alleno
Summary: The influence of self-substitution on the microstructure and thermoelectric properties of the Fe2VAl Heusler alloy was systematically investigated in the Fe2V1+xAl1-x, Fe2+xVAl1-x, Fe2-xV1+xAl series. The study found that self-substitution affects the lattice parameter and thermal conductivity, but increases the thermoelectric power factor, leading to improved thermoelectric performance.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Inorganic & Nuclear
Nisha, Hardev S. Saini, Sunita Srivastava, Manish K. Kashyap
Summary: The study investigates the structural, electronic, and transport properties of Half-Heusler compound TaIrGe under different strains using DFT and Boltzmann transport theory. It is found that tensile and compressive strains significantly alter the energy bandgap, lattice thermal conductivity, and power factor, affecting the performance of the thermoelectric material.
JOURNAL OF SOLID STATE CHEMISTRY
(2021)
Article
Nanoscience & Nanotechnology
Wenjie Li, Gagan K. Goyal, David Stokes, Lavanya Raman, Subrata Ghosh, Shweta Sharma, Amin Nozariasbmarz, Na Liu, Saurabh Singh, Yu Zhang, Bed Poudel, Shashank Priya
Summary: Thermoelectric (TE) materials have advanced rapidly in the past decade, allowing for the design of solid-state waste heat recovery systems. This study focuses on the design and manufacturing of full-scale TE devices with high power generation. Through the use of automated manufacturing processes and optimized coating layers, a remarkably high output power of 38.3 W was achieved. These results pave the way for widespread utilization of TE technology in waste heat recovery applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Magnus Klove, Sanna Sommer, Bo B. Iversen, Bjork Hammer, Wilke Dononelli
Summary: A machine learning model incorporating density functional theory calculations and comparison of PDFs can be used to determine the crystal structure of unknown compounds, allowing for the identification of metastable configurations and stacking disorders.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Jonas Ruby Sandemann, Thomas Bjorn Egede Gronbech, Kristoffer Andreas Holm Stockler, Feng Ye, Bryan C. Chakoumakos, Bo Brummerstedt Iversen
Summary: ZnFe2O4 exhibits spin-glass transition and has dominant ferromagnetic and antiferromagnetic correlations. The 3D-m Delta PDF method is used to visualize the local magnetic ordering preferences.
ADVANCED MATERIALS
(2023)
Article
Chemistry, Physical
Nils Lau Nyborg Broge, Andreas Dueholm Bertelsen, Frederik Sondergaard-Pedersen, Bo Brummerstedt Iversen
Summary: High-entropy alloys (HEAs) are a promising class of materials with extraordinary properties and customization potential through stoichiometry changes. This study presents a solvothermal method for synthesizing eight-component Pt-Ir-Pd-Rh-Ru-Cu-Ni-Co nano-HEA nanoparticles, which can be produced in large quantities. The method relies on simple autoclaves and in situ X-ray scattering experiments suggest auto-catalyzed growth of the particles, extending understanding of HEA nanomaterials.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Jiawei Zhang, Daisuke Ishikawa, Michael M. Koza, Eiji Nishibori, Lirong Song, Alfred Q. R. Baron, Bo B. Iversen
Summary: We have revealed the correlation between loosely bonded atoms and strong anharmonicity in thermoelectric material InTe, using chemical bonding analysis, inelastic X-ray and neutron scattering, and first principles phonon calculations. Our findings indicate that highly anharmonic phonons in InTe arise from the covalency between delocalized In1+ 5s(2) lone pair electrons and Te 5p states. This work provides insights into the microscopic origin of strong anharmonicity in rattling atoms and has implications for designing efficient thermoelectric materials.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Physics, Applied
Karl F. F. Fischer, Bjarke B. Demant, Lasse R. Jorgensen, Bo B. Iversen
Summary: Ruthenium arsenide can be made p-type by adding germanium, and it has a wide substitution range without affecting stability. RuAs2-xGex (x = 0.02, 0.04, 0.08, 0.16, 0.32, and 0.64) shows that the saturation limit of germanium is between 0.16 and 0.32. The electrical contribution to thermoelectric performance is greatly improved with a power factor of 1.03 mW/(m K-2). However, the lattice rigidity is not affected by substitution, as the Debye temperature remains around 420 K, resulting in a modest maximum zT of 0.11.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Physical
Sajesh P. Thomas, Anna Worthy, Espen Z. Eikeland, Amy J. Thompson, Arnaud Grosjean, Kasper Tolborg, Lennard Krause, Kunihisa Sugimoto, Mark A. Spackman, John C. McMurtrie, Jack K. Clegg, Bo B. Iversen
Summary: This article reports a mechanically flexible one-dimensional coordination polymer that exhibits elastic bending. By utilizing various techniques including XRD, high-pressure crystallography, synchrotron micro-XRD mapping, and high-resolution synchrotron X-ray charge density analysis, the inter and intra-chain bonding as well as structural flexibility were quantitatively investigated. The results reveal that the helical coordination polymer behaves like a spring when subjected to external stimuli. The exceptional coordination sphere flexibility, attributed to the presence of Jahn-Teller distorted coordination bonds, contributes to the polymer's flexibility.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Brian Dusolle, Veronique Jubera, Evgeniy S. Ilin, Patrick Martin, Gilles Philippot, Matthew R. . Suchomel, Bo B. Iversen, Samuel Marre, Cyril Aymonier
Summary: Extensive research on nanosized ZnO finds its optical properties challenging to control due to various possible defects producing emissions in the visible range. A low-temperature, supercritical-fluid-driven synthesis proposed by our group produces isotropic nanosized particles with a pure excitonic emission comparable to single crystals. This article reports the growth mechanism and optical properties of the excitonic emission, as well as its phonon coupling with the E2 high vibrational mode at liquid helium temperatures.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Multidisciplinary
Kasper Tolborg, Aron Walsh
Summary: The researchers investigated the tetragonal-to-cubic phase transition of ZrO2 at high temperatures using anharmonic lattice dynamics and molecular dynamics simulations. They found that the stability of cubic zirconia cannot be solely explained by anharmonic stabilization, but may also involve spontaneous defect formation and entropic stabilization, which is responsible for its superionic conductivity at elevated temperatures.
CRYSTAL GROWTH & DESIGN
(2023)
Article
Chemistry, Physical
Gabriel Krenzer, Johan Klarbring, Kasper Tolborg, Hugo Rossignol, Andrew R. McCluskey, Benjamin J. Morgan, Aron Walsh
Summary: In this study, molecular dynamics simulations were used to investigate the type-II superionic phase transition in α-Li3N. The findings suggest that the superionic transition may be driven by a decrease in defect formation energetics rather than changes in Li transport mechanism. This insight may have implications for other type-II superionic materials.
CHEMISTRY OF MATERIALS
(2023)
Article
Chemistry, Physical
Lise Joost Stockler, Rasmus Stubkjaer Christensen, Magnus Klove, Andreas Dueholm Bertelsen, Anders Baek Borup, Lennard Krause, Seiya Takahashi, Tomoki Fujita, Hidetaka Kasai, Ichiro Inoue, Eiji Nishibori, Bo Brummerstedt Iversen
Summary: Promising results were obtained from PDF analysis using X-ray scattering data on a suspension of HfO2 nanoparticles measured at the SACLA XFEL facility. The study encourages further research in ultrafast structural science.
Article
Chemistry, Multidisciplinary
Jonas Ruby Sandemann, Kristoffer Andreas Holm Stockler, Xiaoping Wang, Bryan C. Chakoumakos, Bo Brummerstedt Iversen
Summary: Accurate structural models are crucial for understanding the structure-property relationships in functional materials. This study focuses on the complex crystal structures of spinels and establishes a benchmark crystal structure for defect-free spinel ferrite ZnFe2O4. Various diffraction techniques are used to provide reference data for testing and refining structural models. The results demonstrate the significance of atomic displacement parameters in accurately describing the cation inversion in spinel-type materials.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Chemistry, Multidisciplinary
Irea Mosquera-Lois, Sean R. Kavanagh, Johan Klarbring, Kasper Tolborg, Aron Walsh
Summary: Defects play a crucial role in determining the properties and applications of materials. The theoretical understanding of defect formation in crystals has significantly advanced with the advent of supercomputing hardware and computational techniques such as machine learning. This Tutorial Review provides an overview of the description of free energies for defect formation at finite temperatures and discusses recent progress and challenges in accurately predicting defects in computational materials chemistry.
CHEMICAL SOCIETY REVIEWS
(2023)
Article
Materials Science, Multidisciplinary
Kasper Tolborg, Aron Walsh
Summary: Hybrid organic-inorganic materials are promising as flexible and Pb-free piezoelectric materials, but their properties deteriorate at high temperatures due to ferroelectric-to-paraelectric phase transitions. In this study, a model Hamiltonian for the archetypical hybrid organic-inorganic piezoelectric TMCMCdCl3 is developed using first-principles calculations to simulate the order-disorder phase transition. It is found that the inclusion of vibrational entropy is necessary to accurately reproduce the phase transition temperature, highlighting the significance of vibrational contributions for the phase stability of soft and flexible materials. Additionally, the formation of defective structures and intergrowths at ambient temperature is suggested to explain the exceptional piezoelectric response of these materials, which cannot be accounted for by the conventional small-displacement limit.
JOURNAL OF MATERIALS CHEMISTRY C
(2023)
Article
Chemistry, Multidisciplinary
Ju Huang, Seung-Jae Shin, Kasper Tolborg, Alex Ganose, Gabriel Krenzer, Aron Walsh
Summary: Through molecular dynamics simulations, it is found that the local structures of layered covalent organic frameworks (COFs) deviate from the average crystal structures determined by X-ray diffraction experiments. The simulations using a machine learning force field show that the stacking behavior of COFs is more complex than previously understood.
MATERIALS HORIZONS
(2023)
