Thermoelectric Performance of Surface-Engineered Cu_1.5-Te-Cu₂Se Nanocomposites

Area of Science:

• Materials Science
• Solid State Physics
• Energy Conversion

Background:

• Copper chalcogenides like Cu2S and Cu2Se are promising medium-temperature thermoelectric materials.
• Copper telluride (Cu2-Te) typically has low Seebeck coefficients, limiting its thermoelectric figure of merit (zT).

Purpose of the Study:

• To investigate the thermoelectric performance of Cu1.5Te-Cu2Se nanocomposites.
• To address the limitations of copper telluride in low-temperature thermoelectric applications.

Main Methods:

• Surface engineering of Cu1.5Te nanocrystals.
• Consolidation of engineered nanocrystals into nanocomposites.
• In situ high-temperature X-ray diffraction and differential scanning calorimetry to confirm phase transitions.
• Analysis of thermoelectric properties including Seebeck coefficient, electrical conductivity, and thermal conductivity.

Main Results:

• Achieved a reversible phase transition around 600 K in Cu1.5Te-Cu2Se nanocomposites.
• Observed a conversion from metallic-like to semiconducting-like thermoelectric properties post-phase transition.
• Cu2Se layer on Cu1.5Te nanoparticles inhibited grain growth, reducing thermal conductivity.
• Decreased hole concentration was observed.
• A high dimensionless thermoelectric figure of merit (zT) of 1.3 was achieved at 560 K.

Conclusions:

• Surface-engineered copper telluride-copper selenide nanocomposites demonstrate significant thermoelectric potential.
• The developed strategy effectively enhances the thermoelectric performance of copper telluride-based materials.
• These findings suggest a viable pathway for utilizing copper telluride in efficient thermoelectric devices.