Chemistry in Advancing Thermoelectric GeTe Materials.

Area of Science:

• Materials Science
• Solid State Physics
• Sustainable Energy

Background:

• The global energy crisis and environmental concerns necessitate sustainable energy solutions, with thermoelectrics offering a promising zero-emission alternative.
• Developing high-performance, lead-free, and low-toxicity thermoelectric materials is a key challenge for widespread adoption.
• Germanium telluride (GeTe) derivatives are explored as potential replacements for toxic thermoelectric materials.

Purpose of the Study:

• To summarize recent progress in developing high-performance GeTe-based thermoelectric materials.
• To explore innovative strategies for enhancing electron transport and reducing phonon propagation in GeTe.
• To provide insights for developing advanced thermoelectric materials and devices.

Main Methods:

• Theoretical calculations to understand intrinsic carrier concentration in GeTe due to germanium vacancies.
• Aliovalent doping/alloying and molecular orbital theory to optimize band structure and electronic transport.
• Alloying with heavy atoms (e.g., Sb), introduction of planar vacancies, and superlattice precipitates to reduce lattice thermal conductivity.

Main Results:

• Identified Ge vacancies as the cause of high intrinsic carrier concentration in GeTe, hindering performance.
• Demonstrated strategies to tune carrier concentration via aliovalent doping and achieve band convergence for improved electronic properties.
• Achieved significantly reduced lattice thermal conductivity through alloying and defect engineering, enhancing overall thermoelectric performance.

Conclusions:

• Optimizing carrier concentration and minimizing lattice thermal conductivity are key to enhancing GeTe-based thermoelectric materials.
• The presented strategies offer a roadmap for developing high-performance, environmentally friendly thermoelectric materials.
• Further development of GeTe for device applications holds significant promise for sustainable power generation and refrigeration.