Advanced GeTe-Based Thermoelectrics: Charting the Path from Performance Optimization to Devices

Thermoelectric (TE) materials can interconvert electricity into heat, rendering them versatile for refrigeration and power generation. GeTe as a distinguished TE material has attracted considerable focus owing to its excellent TE performance. Herein, the milestones of research progress on GeTe are reviewed. The intrinsic potentials of GeTe are elaborated, mainly focusing on crystal structure, band structure and microstructures. The path of GeTe-based thermoelectrics from performance optimization to the devices is attempted to chart, referring to its shortcomings and characteristics. Primarily, optimization of the synthesis process is implemented to inhibit the generation of Ge precipitates and phonon migration. Furthermore, the thermoelectric performance of GeTe is enhanced through its features, including phase transition, multiple valence bands, and various microstructures via doping and alloying. Subsequently, the advancements of GeTe thermoelectric devices are presented from the aspect of device integration. Eventually, the prospect and challenges for the future direction of GeTe-based materials are proposed, offering a roadmap to inject vitality into further developments.