Selective Interfacial Barriers Drive High-Performance GeTe Thermoelectrics

Area of Science:

• Materials Science
• Nanotechnology
• Sustainable Energy

Background:

• Thermoelectric technology offers sustainable waste heat harvesting.
• High efficiency requires high figure of merit (ZT) materials, often limited by carrier and phonon coupling.
• Decoupling charge and heat transport is key for improved ZT.

Purpose of the Study:

• To introduce VSe2 nanowire precipitates as selective interfacial barriers.
• To optimize electron transport and suppress phonon transport for enhanced thermoelectric performance.
• To achieve high ZT values for efficient waste heat recovery.

Main Methods:

• Constructing selective interfacial barriers using VSe2 nanowire precipitates in a GeTe matrix.
• Optimizing electron transport by minimizing Fermi level mismatch and reducing interface state density.
• Suppressing phonon transport via significant phonon frequency mismatch at interfaces.

Main Results:

• Achieved a high ZT of 2.7 at 773 K.
• Obtained a record-high average ZT of 1.9 across 300-773 K in (Ge0.82Mn0.04Bi0.04Pb0.1Te)0.99(VSe2)0.01.
• Demonstrated a π-type module with 11.4% conversion efficiency under a 440 K temperature difference.

Conclusions:

• Selective interfacial barriers effectively decouple charge and heat transport.
• The developed material shows significant potential for advanced thermoelectrics and energy harvesting.
• This approach paves the way for more efficient waste heat recovery systems.