Symposium FH
ABSTRACTS
Session FH-1 Thermoelectric materials research & characterization
FH-1:IL01 Transverse Thermoelectrics
K. UCHIDA, National Institute for Materials Science, Tsukuba, Japan; The University of Tokyo, Kashiwa, Japan
Transverse thermoelectric effects interconvert charge and heat currents in orthogonal directions due to the breaking of either time-reversal symmetry or structural symmetry, enabling simple and versatile thermal energy harvesting and solid-state cooling/heating within single materials. In comparison to the complex module structures required for the conventional Seebeck and Peltier effects, the transverse thermoelectric effects provide the complete device structures, potentially resolving the fundamental issue of multi-module degradation of thermoelectric conversion performance. In this talk, we provide an overview of currently known transverse thermoelectric conversion phenomena and principles, as well as their characteristics, and reclassifies them in a unified manner. To discuss the performance of the transverse thermoelectric conversion, thermal boundary conditions play an essential role. Examples of recent application research and material development in transverse thermoelectrics are also introduced, followed by a discussion of future prospects.
FH-1:IL02 Discovery and Development of Half-Heusler Thermoelectric Materials
CHENGUANG FU, TIEJUN ZHU, Zhejiang University, Hangzhou, China
Half-Heusler compounds with the valence electron count of 18 represent a class of semiconductors that hold significant promise as high-performance thermoelectric materials for power generation. The discovery of these semiconducting half-Heusler systems traces back to the 1990s, when ternary MNiSn alloys (M = Ti, Zr, Hf)—comprising three metallic constituents—were first identified to exhibit semiconducting properties. This lecture will comprehensively review the discovery and developmental trajectory of half-Heusler thermoelectric semiconductors, with a focused emphasis on n-type MNiSn, the most representative half-Heusler system to date. Key topics include the processing techniques and microstructural characteristics, as well as their correlation with thermoelectric transport properties. Beyond n-type systems, this lecture will also highlight advancements in typical p-type half-Heusler compounds, such as MCoSb and NbFeSb. Finally, emerging research directions for half-Heusler thermoelectrics will be discussed to outline future challenges and opportunities.
FH-1:IL03 New Directions in Half-Heusler Thermoelectric Materials
J.-W.G. BOS, EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, UK
Thermoelectric conversion can be used to generate renewable power, scavenge heat and is applied in thermal management. Due to their large power densities, half-Heusler materials are amongst the leading contenders for application in generator devices and have been earmarked for high heat pumping applications. This presentation will give an overview of recent work on understanding thermoelectric transport in half-Heusler materials. This includes the impact of dopants present at the few percent level, such as interstitial Cu in the n-type XNiSn compositions [1], and large fractions of aliovalent alloying elements in complex half-Heusler compositions, such as Zn0.5Ti0.5NiSb [2]. Both routes offer opportunities for high thermoelectric performance.
[1] R. J. Quinn et al. Advanced Physics Research, 2400179 (2025); B.F. Kennedy et al. Chemical Communications, 61 7117 (2025). [2] B. F. Kennedy et al. Journal of Materials Chemistry A, 11, 23566 23575 (2023).
FH-1:IL04 Development of High-efficiency Thermoelectric Materials Utilizing Magnetism
TAKAO MORI, National Institute for Materials Science (NIMS), Tsukuba, Japan
Development of thermoelectric (TE) materials is important, for power generation and IoT [1]. For high TE performance, traditional tradeoffs between Seebeck coefficient S and electrical conductivity, etc., have to be overcome [2]. We have shown that magnetism can be utilized to enhance S and overall power factor (PF) in various material systems like sulfides, skutterudites, tellurides, Heusler alloys, etc. When strong coupling of electrical carriers and magnetic moments are realised, not just magnon drag but we have discovered the more easily implemented paramagnon drag can enhance the PF. Recently, spin fluctuation was also demonstrated to enhance the S in the Heusler alloy Fe2VAl system [3]. Magnetic interactions also led to ZT~0.8 and a power factor of 6.7 mWK−2m−1 at room temperature in p-type Fe2VAl, which are factors larger than the best values ever reported [4]. Magnetic scattering effects can also be utilized for band structure engineering leading to high TE performance [5].
[1] MRS Bull., 43, 176 (2018), Sci. Tech. Adv. Mater. 19, 836 (2018), JOM, 68, 2673 (2016). [2] Small 13, 1702013 (2017), Energies, 15, 7307 (2022). [3] Science Adv., 5, eaat5935 (2019), Mater. Today Phys. 48, 101568 (2024). [4] Sci. Tech. Adv. Mater., 26, 2512705 (2025). [5] Science Adv. in press.
FH-1:IL05 Ceramic Thermoelectrics: Bridging Design and Performance
A.V. KOVALEVSKY, D. LOPES, P. AMIRKHIZI, M.A. VIEIRA, S. RASEKH, A.A. YAREMCHENKO, CICECO – Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, Aveiro, Portugal; N.M. FERREIRA, F.M. COSTA, i3N, Physics Department, University of Aveiro, Aveiro, Portugal; WENJIE XIE, A. WEIDENKAFF, Materials and Resources, Techn. Universität Darmstadt, Darmstadt, Germany; E. GUILMEAU, G. RIOU, Laboratoire CRISMAT, UMR 6508, CNRS, ENSICAEN, Caen Cedex, France; A. SOTELO, INMA, CSIC-Universidad de Zaragoza, Zaragoza, Spain
Thermoelectric (TE) materials enable the direct conversion of heat into electricity and vice versa, offering a reliable solid-state route for energy harvesting and cooling. Their potential for recovering waste heat from industrial processes, transport systems, and remote installations is increasingly recognised as essential for sustainable energy management. Among available material classes, ceramic thermoelectrics, particularly oxide-based systems, stand out for their remarkable thermal and chemical robustness, scalability, and reliance on earth-abundant elements. These features make them ideal candidates for high-temperature and long-lifetime operation. In contrast to conventional TE materials that depend on scarce or unstable components, oxides provide a pathway towards environmentally benign and cost-effective solutions. Yet, their wider implementation demands innovative approaches to overcome limitations in electrical and thermal transport. This presentation highlights recent progress and emerging trends in the design and processing of ceramic thermoelectrics, including composite architectures, defect and redox engineering, cation substitution, and advanced fabrication routes such as laser-assisted processing.
FH-1:IL06 Designing Thermoelectrics by Tailoring Chemical Bonds
M. WUTTIG1,2, YUAN YU1, 1Institute of Physics IA, RWTH Aachen University, Aachen, Germany; 2Peter-Grünberg-Institute (PGI 10), Forschungszentrum Jülich, Jülich, Germany
Thermoelectrics combine an interesting portfolio of properties. They possess a small thermal but a reasonably large electrical conductivity and a rather high Seebeck coefficient. This combination of properties is quite rare; but attractive for a number of applications. These properties are particularly desirable for thermoelectrics which can convert waste heat into electrical energy. Hence, different strategies have been devised to identify and tailor materials for thermoelectric applications. Recently, we have developed a design concept for thermoelectrics which is based upon an in-depth understanding of the underlying bonding mechanism. In particular, we can show that many chalcogenide- and pnictogen- based thermoelectrics employ an unconventional bonding mechanism, which differs considerably from ordinary covalent, metallic or ionic bonding. This bonding mechanism is identified by a unique property portfolio. Some of the characteristic properties are highly beneficial for thermoelectric applications including the low thermal conductivity and the modest electrical conductivity. We will unravel the origin of these unusual features and relate them to a special bonding mechanism in these chalcogenides, which has been coined metavalent bonding.
FH-1:IL07 Revisiting Cu in Bi2Te3 Based Compounds
WENJIE XIE, Institute of Materials Science, Technical University of Darmstadt, Darmstadt, Germany
The effects of Cu impurities in bismuth telluride, discovered during thermoelectric device manufacturing, have been known for decades. However, the precise structural site occupied by Cu atoms and its resulting doping mechanism remain unclear. Cu is observed to increase charge carrier concentration in both p- and n-type Bi₂Te₃. This leads to two conflicting hypotheses: (1) Cu intercalates in the van der Waals gaps, acting as an electron donor, or (2) Cu substitutes for Bi/Sb, which would act as an electron acceptor—a model at odds with its n-type doping capability. This talk will elucidate these contradictory findings by employing the framework of defect chemistry. We will synthesize existing experimental data to develop a consistent model that explains the amphoteric behavior of Cu in bismuth telluride.
FH-1:IL08 Ab Initio Calculations of the Thermoelectric Figure of Merit
L. CHAPUT, Université de Lorraine, Nancy, France; and Institut Universitaire de France, Paris, France
Within the last 10 years, it has been possible to compute phonon-phonon interactions, and therefore the lattice thermal conductivity of bulk materials, using ab initio methods. The interactions between the phonons are obtained from density functional theory and this information is incorporated into the Boltzmann equation to obtain the lattice thermal conductivity. The good accuracy obtained from those calculations allows trying to use them to find new materials using artificial intelligence and to perform multiscale modelling. Along the same lines, it is now possible to compute electron-phonon interactions from ab initio calculations, and therefore to obtain electronic transport coefficients, such as electrical conductivity and thermopower. Together those computational approaches allow for an ab initio calculation of the thermoelectric figure of merit ZT. I will discuss a few examples of such calculations, our recent implementations in the VASP code, as well as thoughts about future works.
FH-1:IL09 Enhanced Thermoelectric Performance of SrTiO3 with Metallic Nanoparticles Exsolved under Reducing Conditions
MICHITAKA OHTAKI, RYUSEI MAEDA, LEO AOKI, KOICHIRO SUEKUNI, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Japan
Here we report exsolution of Ni nanoparticles from Ni-doped SrTiO3 and an improved thermoelectric performance of the oxide via independently controlled carrier mobility and carrier concentration by chemical pathways such as hydrogen reduction. Sr1–x(Ti0.8Nb0.2)1–yNiyO3 (x,y = 0, 0.05, 0.10) was synthesized by solid state reaction. After sintering in air at 1420 °C, the samples were reduced under 20% H2/N2 or 100% H2 at 1350 °C. Whereas the electrical conductivity σ of the samples showed metallic behavior and significantly varied from 200 to 1900 S/cm at room temperature, the Seebeck coefficient S at the same temperature was within a narrow range of –50 to –80 μV/K. The molar fractions of Ni0, f(Ni0), obtained from the XPS spectra widely varies from 0.5 to 55% depending on the reducing conditions such as the H2 concentrations in the reaction atmosphere, while f(Ti3+) stays within 16 – 18% for all the samples. This analysis clearly explains the discrepant behavior of σ and S, the former being tuned by the amount of the metallic Ni particles forming conduction paths, while the latter being governed by the carrier concentrations in the STO matrix. A highest ZT of 0.37 at 800 °C was achieved by the sample with the largest amount of Ni0.
FH-1:IL10 Thermoelectric Properties in Pyrites and Metal Rich Sulfides
S. HÉBERT, Laboratoire CRISMAT Normandie Université, UMR6508 CNRS, ENSICAEN, UNICAEN, Caen, France
Among chalcogenides, different families of sulfides have attracted interest due to their promising power factor S2/r or large figure of merit ZT= S2T/(rk) (S the Seebeck coefficient, r the electrical resistivity and r the thermal conductivity) [1]. Some of these sulfides also present large transverse thermoelectric effects, with for example a large Nernst effect in the shandite Co3Sn2S2 [2]. We will show here the results obtained focusing on metallic sulfides such as pyrites [3] or metal rich sulfides [4], in which the electronic transport properties come from a complex interplay between magnetism and transport [3] or from an original crystallographic structure [4]. The different approaches followed to optimize their properties will be presented.
[1] : A. V. Powell et al., J. Appl. Phys. 126, 100901 (2019). [2] : S. N. Guin et al., Adv. Mater. 31, 1806622 (2019). [3] : S. Hébert et al., J. Appl. Phys. 114, 103703 (2013) ; U. Acevedo Salas, Phil. Trans. R. Soc. A 377, 20180337 (2019). [4] : A. Maignan et al., J. Appl. Phys. 136, 235102 (2024); L. Agnarelli et al., ChemComm 10.1039/d5cc03147h (2025).
FH-1:L11 Metallurgical Processing of Intermetallic Compounds for Thermoelectric Waste Heat Harvesting
A. CASTELLERO, X. HUANG, E. BERARDINO, M. BARICCO, Università di Torino, Dipartimento di Chimica, NIS, INSTM, Turin, Italy; C. FANCIULLI, CNR - ICMATE, Lecco, Italy; A. FERRARIO, S. BOLDRINI, CNR - ICMATE, Padova, Italy
Large-scale production of thermoelectric (TE) generators requires the use of materials affordable in terms of supplying and cost, with reproducible as well as reliable thermoelectric and thermophysical properties. In this work, we focused on Half Heusler alloys for medium/high temperature (400-600 °C), ZnSb and Zn4Sb3 intermetallic compounds for medium/low temperature (RT-400°C). Various metallurgical processing routes were employed for the Half Heusler alloys in order to optimize thermoelectric and mechanical properties by microstructure refinement. The effect of doping and processing on the thermoelectric properties of ZnSb and Zn4Sb3 intermetallic compounds was investigated, in order to reach a conversion efficiency comparable to that of commercial systems, currently based on toxic and critical raw materials, such as Te. Samples produced by the different processing routes were characterized from the structural, microstructural, thermal, mechanical and thermoelectric point of view. The effect of the process on the microstructure, transport and mechanical properties is outlined. Materials with optimized properties were selected for assembling lab-scale thermoelectric generator prototypes.
Financial support from “Ricerca di sistema elettrico - Piano Triennale 2025-2027”.
FH-1:L13 Optimizing Thermoelectric Performance in Double Heusler Alloys via Data-Driven Materials Design
D.R. BAIGUTLIN, V.V. SOKOLOVSKIY, S.V. TASKAEV, Chelyabinsk State University, Chelyabinsk, Russian Federation
Double half-Heusler (DHH) alloys are ordered, aliovalent derivatives of the half-Heusler motif (X₂Y′Y″Z₂), created by doubling the unit cell and placing two distinct species on one sublattice. This ordering introduces mass and force-constant contrast that intrinsically suppresses lattice thermal conductivity while preserving favorable band edges. We use this advantage to build a practical screening of the full aliovalent space, covering 1,064 compositions. A hiphive model, trained on density functional perturbation theory phonons for a chemically diverse set, learns force constants and then predicts temperature dependent lattice thermal conductivity for every candidate. We combine these predictions with constant relaxation time electronic transport from BoltzTraP2 to estimate the thermoelectric figure of merit between 300 and 1200 K. The surrogate matches phonon Boltzmann references within about 15 % on unseen compounds and cuts the cost by orders of magnitude. The screen reveals families with lattice thermal conductivity below about 2 W/(m*K) near 700 K and strong power factor potential. From these results we extract simple design rules and provide a shortlist of candidates for experiment.
Session FH-2 Device research and modeling
FH-2:IL14 High-Throughput Printing of High-Performance and Low-Cost Thermoelectric Materials and Devices
YANLIANG ZHANG, University of Notre Dame, Notre Dame, IN, USA
Thermoelectric devices offer tremendous opportunities in direct conversion of waste heat into electricity and solid-state refrigeration with no moving parts or environmental emission from refrigerants. To realize its broad applications in energy harvesting and thermal management, significant advances are required to not only increase thermoelectric figure of merit zT but also improve the mechanical flexibility and reduce the manufacturing time and cost. Here, we present novel and scalable ink-based printing methods that enable high-throughput development and lowcost manufacturing of thermoelectric materials and devices. An aerosol based high-throughput combinatorial printing (HTCP) method is developed to accelerate the discovery and optimization of high-efficiency thermoelectric materials. Highly scalable and lowcost extrusion printing and screen-printing processes were applied to transform high-efficiency thermoelectric particles into high-performance devices. The thermoelectric power factor in our printed p-type materials reaches 3500 μW/mK2, which is by far the highest in printed TE materials. This results in highly competitive room temperature ZT of 1.3. The scalable printing methods can enable film-based devices manufactured with the optimum thicknesses and form factors to
FH-2:IL16 Thermionic-Thermoelectric Generators in Sensible Heat Thermal Batteries
A. BELLUCCI, CNR-ISM - Istituto di Struttura della Materia del Consiglio Nazionale delle Ricerche, Monterotondo scalo (RM), Italy
Thermoelectric and thermionic energy conversion are key enablers for direct heat-to-electricity transformation. The integration of these mechanisms within high-temperature thermal storage systems opens new routes to efficient and dispatchable renewable power generation. Within the EU project BLAZETEC (www.blazetec.eu), we explore the development of Thermionic-Thermoelectric Generators (TITEGs) coupled with Sensible Heat Thermal Batteries, aiming to convert stored heat into electricity during discharge cycles to deliver on-demand electrical power. The presentation will discuss the multi-physics modelling, device optimization, and materials challenges associated with hybrid thermionic-thermoelectric devices operating at 1200–1600 °C, as well as preliminary experimental activities on prototypes to demonstrate the potential of TITEGs. Special emphasis will be placed on materials innovation, interfacial engineering, thermal coupling, minimization of heat losses and possibility of co-generation (e.g., hot water). The combination of thermionic and thermoelectric effects within a single device architecture enhances conversion efficiency beyond conventional thermoelectric modules, while maintaining possibility of co-generating (i.e., hot water).
FH-2:IL17 Development of Heat Flux Sensor Using Anomalous Nernst Effect: New Materials and Applications
YUYA SAKURABA, WEINAN ZHOU, NIMS, Tsukuba, Japan; YUTARO TABATA, SYUJI INAMURA, MANABU ORITO, KATSUHISA TAGUCHI, SEMITEC
Heat flux sensors (HFS) are promising thermoelectric devices for directly detecting the direction and magnitude of heat flow. However, conventional Seebeck-based HFS suffer from high thermal resistance and cost due to their complex leg structure, which stems from the one-dimensional nature of the Seebeck effect. The anomalous Nernst effect (ANE) in magnetic materials, which generates an electric field perpendicular to the heat flow and magnetization, offers a promising alternative. It enables simpler devices with lateral meander-shaped wire structures. Our early ANE-HFS prototypes, reported in 2021, demonstrated a linear response to heat flux but had low sensitivity. Recent developments using materials such as Co₂MnGa, Fe-Ga, Sm-Co, and Co-Gd alloys have improved sensitivity, though challenges remain—particularly high electrical resistance and Seebeck offset voltage. To address these, we introduced new idea to reduce electric resistance and Seebeck offset voltage while maintaining output voltage. In this presentation, we will share recent advancements in material development and ANE-based heat flux sensor design.
FH-2:IL19 Micro-Thermoelectric Devices
H. REITH1, N.B. PULUMATI1,2, A. SUNDAR1,2, K. NIELSCH1,2, 1Institute for Metallic Materials, Leibniz Institute of Solid State and Materials Research, Dresden, Germany; 2TU Dresden, Faculty of Mechanical Engineering, Dresden, Germany
Micro thermoelectric devices (µTEDs) are promising for localized thermoelectric cooling (TEC) and generation (TEG), enabling efficient hotspot management and self-powered operation in miniaturized systems. Electrochemical deposition (ECD) provides a versatile, cost-effective fabrication route with precise geometry control, tunable composition, and compatibility with standard microfabrication. We introduce a height-optimization strategy that increases packing density, cooling power, and output power while reducing toxic thermoelectric material use. µTEDs are fabricated via photolithography and ECD of Bi₂(TeₓSe₁₋ₓ)₃ (n-type) and Te (p-type). N₂ injection reduces oxygen, lowering contact resistance and improving ΔT and cooling density. Geometry optimization increases ZT, with area- and height-optimized µTEDs achieving cooling of 10.8 K and 10.5 K at room temperature. Finite element simulations predict cooling densities of hundreds of W cm⁻². In TEG mode, µTEDs deliver high open-circuit voltages and mW cm⁻² power densities, sufficient to avoid DC–DC converters. Compact, efficient, and scalable, these µTEDs enable high-density integration and applications in IoT, biomedicine, and localized thermal management.
Session FH-3 Converter technologies and applications
FH-3:L20 Personalized Thermal Management via Thermoelectric and Textile Heat Exchange Systems
G. LATRONICO, C. FANCIULLI, F. LAZZARI, CNR-ICMATE, Lecco, Italy; G. ROLLO, I. IMPROTA, M. FIUME, M. LAVORGNA, CNR-IPCB, Portici, NA, Italy; S. DEL FERRARO, V. MOLINARO, INAIL-DiMEILA, Monte Porzio Catone, RM, Italy
Rising energy and climate challenges have spurred interest in energy-efficient personal thermoregulation. As thermal comfort varies, research targets personalized solutions to improve comfort and cut energy use. Personal cooling systems can lower air conditioning demand and provide portable relief for outdoor workers. This work presents a solution from the INAIL-BRIC ID39_2022 SMART-SHIRT project (SMART materials and technologies for thermal-stress & physio-monitoring SHIRT), aimed at improving thermal regulation for workers in high-temperature environments. The system integrates sensors within a t-shirt to capture biometric data in real time, activating a thermoelectric cooling unit to stabilize thermal stress. The design employs an innovative 3D textile heat exchanger while maintaining comfort and mobility. Current efforts focus on lightweight, unobtrusive integration, and a benchmark setup is being developed to evaluate thermal management performance.
FH-3:IL21 Supply-chain, where the Challenge of Commercialization Starts
HAO YIN, TEGnology, Søborg, Denmark
Commercialization of thermoelectrics has lagged behind the research and development activities, thus limiting the further implementation of the solution into scalable applications. As increasing number of use cases are identified, the demand of modules will also increase. However, the supply of thermoelectric modules in recent years has become less stable and resilience. The price of a typical 4x4 cm Bi2Te3 TEG module with decent quality has tripled from 2022 to 2025 on the European markets. And it seems the shortage of material and module supply will continue in the years to come. Alternative, none Te-based thermoelectric materials have existed or being developed for some years, but commercially available modules are still hard to find. Manufacturing these materials might require global supply-chain and logistics, which are facing increasing political and practical challenges. Solving these challenges require engagement and commitment from industry and government, which are often beyond the scope of scientific projects. Cross-organization dialogue and collaboration mechanism should be setup for thermoelectrics.
FH-3:IL22 GemaTEG Ecosystem for Thermal Management of HPC and AI Chips
B. LORENZI, G. CORBUCCI, GemaTEG Italia srl, Perugia, Italy; M. MIOZZA, GemaTEG Inc.
AI workloads are pushing chips to unprecedented power densities, with Thermal Design Power (TDP) rapidly escalating into the multi-kilowatt range. Modern GPUs are no longer uniform heat sources. Their architecture is highly complex, with compute cores, memory blocks, and interconnects each heating up at different times and workloads. The surge in power demand is reshaping data centers, with loads soon reaching 250 kW per rack. Direct Liquid Cooling (DLC) will soon struggle to keep pace with the rapid escalation of TDPs. The only options currently available is lowering facility fluid temperature, an approach that is neither scalable nor sustainable. To address the problem, GemaTEG® has developed DaTEG®, a localized and tunable thermal management system. Based on innovative thermoelectric coolers coupled with advanced heat-exchange assembly, the system enables precise, component-level temperature control. A proprietary embedded software collects real-time IT and thermal data to drive localized cooling for maximum efficiency. The adaptive ecosystem supports operation with inlet fluid temperatures >40 °C, achieving up to 45% lower cooling energy demand relative to DLC solutions. The resulting efficiency gain delivers ≈$50K per MW in annual savings and a payback period below one year.
FH-3:IL23 Durable and Sustainable Thermoelectric Devices made from Magnetsium-antimony Alloys
K. NIELSCH, PINGJUN YING, A. BAHRAMI, RAN HE, Leibniz Institute of Solid States and Materials Research, Dresden, Germany; Institute of Materials Research, Technical University of Dresden, Germany
Thermoelectric technology has witnessed a resurgence due to increasing demands for sustainable energy sources and efficient cooling systems. The introduction of Te-free thermoelectric modules using non-toxic, abundant materials including p-type MgAgSb and n-type Mg3(Sb,Bi)2 marked a significant breakthrough with conversion efficiencies of > 8% under a temperature differences of 250 C. Despite promising performance, questions persist regarding long-term robustness and stability, especially in harsh environments. A thorough exploration of thermoelectric modules is conducted, focusing on their performance degradation under various conditions. Surface coatings using atomic layer deposition (ALD) emerge as a promising solution, particularly by HfO2, demonstrating superior protective effects. Furthermore, re-soldering effectively restores module performance is found, highlighting the importance of developing advanced soldering techniques to promote magnesium-based thermoelectric technology as a sustainable alternative to Bi2Te3. These findings emphasize the importance of exploring novel contact materials and demonstrate the potential of ALD as a universal approach to enhancing module reliability and robustness.