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.

Advanced Thermoelectric Design: From Materials and Structures to Devices

High-performance GeTe-based thermoelectrics have been recently attracting growing research interest. Here, an overview is presented of the structural and electronic band characteristics of GeTe. Intrinsically, compared to low-temperature rhombohedral GeTe, the high-symmetry and high-temperature cubic GeTe has a low energy offset between L and sigma points of the valence band, the reduced direct bandgap and phonon group velocity, and as a result, high thermoelectric performance. Moreover, their thermoelectric performance can be effectively enhanced through either carrier concentration optimization, band structure engineering (bandgap reduction, band degeneracy, and resonant state engineering), or restrained lattice thermal conductivity (phonon velocity reduction or phonon scattering). Consequently, the dimensionless figure of merit, ZT values, of GeTe-based thermoelectric materials can be higher than 2. The mechanical and thermal stabilities of GeTe-based thermoelectrics are highlighted, and it is found that they are suitable for practical thermoelectric applications except for their high cost. Finally, it is recognized that the performance of GeTe-based materials can be further enhanced through synergistic effects. Additionally, proper material selection and module design can further boost the energy conversion efficiency of GeTe-based thermoelectrics.

https://espace.library.uq.edu.au/view/UQ:f9ee361/UQf9ee361_OA.pdf

High-Performance GeTe-Based Thermoelectrics: from Materials to Devices

Research interest in the development of real-time monitoring of personal health indicators using wearable electrocardiographic systems has intensified in recent years. New advanced thermoelectrics are potentially a key enabling technology that can be used to transform human body heat into power for use in wearable electrographic monitoring devices. This work provides a systematic review of the potential application of thermoelectric generators for use as power sources in wearable electrocardiographic monitoring systems. New strategies on miniaturized rigid thermoelectric modules combined with batteries or supercapacitors can provide adequate power supply for wearable electrocardiographic systems. Flexible thermoelectric generators can also support wearable electrocardiographic systems directly when a heat sink is incorporated into the design in order to enlarge and stabilize the temperature gradient. Recent advances in enhancing the performance of novel fiber/fabric based flexible thermoelectrics has opened up an exciting direction for the development of wearable electrocardiographic systems.

Thermoelectric Generators: Alternative Power Supply for Wearable Electrocardiographic Systems.

Linsen Huang

Papers

Texture-dependent thermoelectric properties of nano-structured Bi2Te3

Fabrication of stable high-performance urchin-like CeO2/ZnO@Au hierarchical heterojunction photocatalyst for water remediation.

Preparation and characterization of ternary Cu/Cu2O/C composite: an extraordinary adsorbent for removing anionic organic dyes from water

Construction of Au modified direct Z-scheme g-C3N4/defective ZnO heterostructure with stable high-performance for tetracycline degradation

Fabrication and mechanism exploration of oxygen-incorporated 1T-MoS2 with high adsorption performance on methylene blue