Enhanced Stability and Thermoelectric Performance in Cu_1.85Se-Based Compounds

Area of Science:

• Materials Science
• Solid State Chemistry
• Thermoelectrics

Background:

• Liquid-like copper selenium compounds offer excellent thermoelectric properties, abundant resources, and low toxicity.
• Applications are hindered by phase transitions and copper precipitation under external fields.

Purpose of the Study:

• To develop stable cubic copper selenium compounds with enhanced thermoelectric performance and critical voltage.
• To investigate the effects of Li/Bi co-doping and sulfur alloying on material stability and efficiency.

Main Methods:

• Synthesized cubic Cu1.85Se-based compounds.
• Applied Li/Bi co-doping to optimize hole concentration.
• Introduced sulfur alloying to reduce thermal conductivity.

Main Results:

• Achieved suppressed phase transition and improved critical voltage (Vc > 0.22 V).
• Enhanced thermoelectric figure of merit (ZT) from 0.2 to 0.7 in Li0.03Cu1.81Bi0.04Se.
• Further improved ZT to 0.9 in Li0.03Cu1.81Bi0.04Se0.9S0.1 at 760 K.

Conclusions:

• Li/Bi co-doping and sulfur alloying create a new strategy for stable and high-performance thermoelectric materials.
• The developed copper selenium compounds show significant potential for advanced thermoelectric applications.
• This research opens new avenues for designing robust thermoelectric materials.