Enhancing Thermoelectric Performance through Semiconductor-Semimetal Heterostructure via Entropy- and Enthalpy-Driven...

Area of Science:

• Materials Science
• Solid State Physics
• Nanotechnology

Background:

• Thermoelectric materials convert heat to electricity, crucial for energy harvesting.
• Improving thermoelectric performance requires decoupling electrical and thermal transport.
• BiSbSe3-based materials show promise but require enhanced performance.

Purpose of the Study:

• To develop a phase-regulation strategy for enhancing thermoelectric performance.
• To create a semiconductor-semimetal heterostructure in BiSbSe3.
• To investigate the impact of dopants on phase composition and thermoelectric properties.

Main Methods:

• Incorporation of sulfur and aluminum dopants into BiSbSe3.
• Controlled formation of hexagonal and orthorhombic phases.
• Characterization of electronic structure, carrier transport, and thermal conductivity.
• Compositional regulation to tune phase composition.

Main Results:

• A biphasic semiconductor-semimetal heterostructure was successfully engineered.
• Enhanced carrier concentration without sacrificing mobility was achieved.
• Lattice thermal conductivity was significantly suppressed through phonon scattering and grain refinement.
• A peak thermoelectric figure of merit (zT) of 1.50 at 773 K was obtained.

Conclusions:

• Phase engineering of semiconductor-semimetal heterostructures is an effective strategy for high-performance thermoelectrics.
• The strategy successfully decouples electrical and thermal transport properties.
• The developed BiSbSe3-based material shows significant potential for thermoelectric applications.