Achieving zT ≥ 1.0 in a Cd₃P₂-Based System via Alloying Minor Arsenic

Area of Science:

• Materials Science
• Solid State Physics
• Inorganic Chemistry

Background:

• Thermoelectric materials can convert waste heat into electricity.
• Cadmium phosphide (Cd3P2) is a promising thermoelectric material.
• Optimizing thermoelectric performance requires balancing electrical and thermal transport.

Purpose of the Study:

• To enhance the thermoelectric performance of Cd3P2.
• To investigate the effects of arsenic alloying on Cd3P2.
• To explore potential applications of improved thermoelectric materials.

Main Methods:

• Alloying Cd3P2 with arsenic to create Cd3P1.8As0.2.
• Evaluating thermoelectric properties, including figure of merit (zT).
• Analyzing the mechanisms behind performance enhancement through transport measurements and theoretical calculations.

Main Results:

• The Cd3P1.8As0.2 alloy achieved a peak thermoelectric figure of merit (zT) over 1.0.
• The average zT of the alloy was 0.59, significantly higher than pristine Cd3P2.
• Enhanced performance resulted from decoupling electrical and thermal transport.
• Reduced effective mass improved carrier mobility.
• Arsenic alloying induced defect scattering and lattice anharmonicity, reducing thermal conductivity.

Conclusions:

• Arsenic alloying is an effective strategy to enhance Cd3P2 thermoelectric performance.
• The Cd3P1.8As0.2 system demonstrates significant potential for thermoelectric energy conversion.
• Further theoretical analysis indicates possibilities for continued improvement.