Driven by the ability to harvest waste heat into reusable electricity and the exclusive role of serving as the power generator for deep spacecraft, intensive endeavors are dedicated to enhancing the ...thermoelectric performance of ecofriendly materials. Herein, the most recent progress in superhigh‐performance GeTe‐based thermoelectric materials is reviewed with a focus on the crystal structures, phase transitions, resonant bondings, multiple valance bands, and phonon dispersions. These features diversify the degrees of freedom to tune the transport properties of electrons and phonons for GeTe. On the basis of the optimized carrier concentration, strategies of alignment of multiple valence bands and density‐of‐state resonant distortion are employed to further enhance the thermoelectric performance of GeTe‐based materials. To decrease the thermal conductivity, methods of strengthening intrinsic phonon–phonon interactions and introducing various lattice imperfections as scattering centers are highlighted. An overview of thermoelectric devices assembled from GeTe‐based thermoelectric materials is then presented. In conclusion, possible future directions for developing GeTe in thermoelectric applications are proposed. The achieved high thermoelectric performance in GeTe‐based thermoelectric materials with rationally established strategies can act as a reference for broader materials to tailor their thermoelectric performance.
Recent progress in GeTe thermoelectrics is reviewed with a focus on the diverse degrees of freedom to tailor thermoelectric properties. The strategies for enhancing power factors include optimizing carrier concentration, aligning multiple valence bands, density‐of‐state resonant distortion, and increasing band degeneracy by slight symmetry reduction. Decreasing the thermal conductivity can be achieved by intrinsically strengthening the phonon–phonon interactions and introducing planar vacancies.
As a key type of emerging thermoelectric material, tin telluride (SnTe) has received extensive attention because of its low toxicity and eco‐friendly nature. The recent trend shows that band ...engineering and nanostructuring can enhance thermoelectric performance of SnTe as intermediate temperature (400–800 K) thermoelectrics, which provides an alternative for toxic PbTe with the same operational temperature. This review highlights the key strategies to enhance the thermoelectric performance of SnTe materials through band engineering, carrier concentration optimization, synergistic engineering, and structure design. A fundamental analysis elucidates the underpinnings for the property improvement. This comprehensive review will boost the relevant research with a view to work on further performance enhancement of SnTe materials.
SnTe qualifies as an eco‐friendly alternative to medium‐temperature thermoelectric PbTe by showing robust potential as high‐performance thermoelectrics via effective strategies through band engineering, carrier concentration optimization, synergistic engineering, and structure design.
The long-standing popularity of thermoelectric materials has contributed to the creation of various thermoelectric devices and stimulated the development of strategies to improve their thermoelectric ...performance. In this review, we aim to comprehensively summarize the state-of-the-art strategies for the realization of high-performance thermoelectric materials and devices by establishing the links between synthesis, structural characteristics, properties, underlying chemistry and physics, including structural design (point defects, dislocations, interfaces, inclusions, and pores), multidimensional design (quantum dots/wires, nanoparticles, nanowires, nano- or microbelts, few-layered nanosheets, nano- or microplates, thin films, single crystals, and polycrystalline bulks), and advanced device design (thermoelectric modules, miniature generators and coolers, and flexible thermoelectric generators). The outline of each strategy starts with a concise presentation of their fundamentals and carefully selected examples. In the end, we point out the controversies, challenges, and outlooks toward the future development of thermoelectric materials and devices. Overall, this review will serve to help materials scientists, chemists, and physicists, particularly students and young researchers, in selecting suitable strategies for the improvement of thermoelectrics and potentially other relevant energy conversion technologies.
Due to the nature of their liquid‐like behavior and high dimensionless figure of merit, Cu2X (X = Te, Se, and S)‐based thermoelectric materials have attracted extensive attention. The superionicity ...and Cu disorder at the high temperature can dramatically affect the electronic structure of Cu2X and in turn result in temperature‐dependent carrier‐transport properties. Here, the effective strategies in enhancing the thermoelectric performance of Cu2X‐based thermoelectric materials are summarized, in which the proper optimization of carrier concentration and minimization of the lattice thermal conductivity are the main focus. Then, the stabilities, mechanical properties, and module assembly of Cu2X‐based thermoelectric materials are investigated. Finally, the future directions for further improving the energy conversion efficiency of Cu2X‐based thermoelectric materials are highlighted.
Deriving from their high performance and eco‐friendliness, superionic Cu2X‐based thermoelectric materials are attracting ever‐increasing attention. A comprehensive summary of the understanding of the superionicity, performance enhancement strategies, and material stability design can set up a solid foundation for future development. Pointing out the development challenges can better guide future studies.
The urgent need for ecofriendly, stable, long‐lifetime power sources is driving the booming market for miniaturized and integrated electronics, including wearable and medical implantable devices. ...Flexible thermoelectric materials and devices are receiving increasing attention, due to their capability to convert heat into electricity directly by conformably attaching them onto heat sources. Polymer‐based flexible thermoelectric materials are particularly fascinating because of their intrinsic flexibility, affordability, and low toxicity. There are other promising alternatives including inorganic‐based flexible thermoelectrics that have high energy‐conversion efficiency, large power output, and stability at relatively high temperature. Herein, the state‐of‐the‐art in the development of flexible thermoelectric materials and devices is summarized, including exploring the fundamentals behind the performance of flexible thermoelectric materials and devices by relating materials chemistry and physics to properties. By taking insights from carrier and phonon transport, the limitations of high‐performance flexible thermoelectric materials and the underlying mechanisms associated with each optimization strategy are highlighted. Finally, the remaining challenges in flexible thermoelectric materials are discussed in conclusion, and suggestions and a framework to guide future development are provided, which may pave the way for a bright future for flexible thermoelectric devices in the energy market.
A comprehensive exploration of the material design strategies, processing methods, and underlying physics and chemistry behind the enhanced thermoelectric properties of flexible thermoelectric materials is presented, emphasizing innovative approaches and suggesting future pathways for the development of a new generation of wearable electronics.
With the ever‐increasing demand for wearable electronics and energy‐saving technologies, self‐powered thermoelectric personal thermal management (PTM) has attracted extensive research interest. In ...this review, the unique characteristics of thermoelectric PTM comparing with other technologies are first highlighted, and the key parameters and fundamental functions of thermoelectric PTM are systematically summarized. Then, the advances in thermoelectric PTM are overviewed from the material design to the wearable device design viewpoints. Finally, the key challenges and future research directions of thermoelectric PTM, where both high‐performance flexible materials and proper device designs are in urgent need, are pointed out. This review will deliver a systematic understanding and guideline for thermoelectric PTM.
The increasing demand for wearable electronics has boosted the development of energy‐saving and self‐powered personal thermal management systems. This review highlights the unique advantages of thermoelectric technology comparing with other technologies, summarizes corresponding key parameters, fundamental functions, material and device advancements of thermoelectric personal thermal management, and further points out corresponding future research directions.
Indium selenides have attracted extensive attention in high‐efficiency thermoelectrics for waste heat energy conversion due to their extraordinary and tunable electrical and thermal properties. This ...Review aims to provide a thorough summary of the structural characteristics (e.g. crystal structures, phase transformations, and structural vacancies) and synthetic methods (e.g. bulk materials, thin films, and nanostructures) of various indium selenides, and then summarize the recent progress on exploring indium selenides as high‐efficiency thermoelectric materials. By highlighting challenges and opportunities in the end, this Review intends to shine some light on the possible approaches for thermoelectric performance enhancement of indium selenides, which should open up an opportunity for applying indium selenides in the next‐generation thermoelectric devices.
Indium selenides recently emerged as high‐efficiency thermoelectric materials for waste heat energy conversion. This Review provides a thorough summary of the structural characteristics, synthetic methods, and thermoelectric properties of various indium selenides. By highlighting challenges and opportunities, this Review intends to shine some light on the possible approaches for thermoelectric performance enhancement of indium selenides.
Thermoelectric materials offer an alternative opportunity to tackle the energy crisis and environmental problems by enabling the direct solid-state energy conversion. As a promising candidate with ...full potentials for the next generation thermoelectrics, tin selenide (SnSe) and its associated thermoelectric materials have been attracted extensive attentions due to their ultralow thermal conductivity and high electrical transport performance (power factor). To provide a thorough overview of recent advances in SnSe-based thermoelectric materials that have been revealed as promising thermoelectric materials since 2014, here, we first focus on the inherent relationship between the structural characteristics and the supreme thermoelectric performance of SnSe, including the thermodynamics, crystal structures, and electronic structures. The effects of phonon scattering, pressure or strain, and oxidation behavior on the thermoelectric performance of SnSe are discussed in detail. Besides, we summarize the current theoretical calculations to predict and understand the thermoelectric performance of SnSe, and provide a comprehensive summary on the current synthesis, characterization, and thermoelectric performance of both SnSe crystals and polycrystals, and their associated materials. In the end, we point out the controversies, challenges and strategies toward future enhancements of the SnSe thermoelectric materials.
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