Helical dislocation-driven plasticity and flexible high-performance thermoelectric generator in α-Mg₃Bi₂ single...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Inorganic Chemistry

Background:

• Inorganic plastic semiconductors are vital for flexible electronics.
• Developing new materials with both plasticity and thermoelectric properties is a key challenge.

Purpose of the Study:

• To present a novel, cost-effective plastic thermoelectric semimetal, magnesium bismuthide (α-Mg₃Bi₂).
• To investigate the origin of its remarkable plasticity and thermoelectric performance.
• To demonstrate its potential in flexible thermoelectric generators.

Main Methods:

• Synthesis of bulk single-crystalline α-Mg₃Bi₂.
• Mechanical testing to assess plastic deformation.
• Transmission electron microscopy and time-of-flight neutron diffraction for structural analysis.
• Chemical bonding theoretic analyses.
• Measurement of thermoelectric properties (power factor, normalized power density).

Main Results:

• α-Mg₃Bi₂ exhibits significant plastic deformation at room temperature, enabling fabrication of complex shapes.
• Plasticity is attributed to dislocation-driven interlayer slip, weak Mg-Bi bonds, and low modulus of Mg₂Bi₂^2- networks.
• Achieved a power factor of 26.2 µW cm^-1 K^-2 and a normalized power density of 8.1 μW cm^-2 K^-2 in flexible devices.

Conclusions:

• Plastic magnesium bismuthide (α-Mg₃Bi₂) is a promising material for flexible electronics.
• Its unique combination of plasticity and thermoelectric performance opens new avenues for deformable electronic devices.
• This material advances the development of high-performance flexible thermoelectric generators.