1. Thermoelectric properties of Bi2Te3 films with low-angle grain boundaries formed through high pulse current density.
- Author
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Lan, Mingdi, Sun, Shang, Liu, Shiying, Li, Guojian, Sun, Xiao, and Wang, Qiang
- Subjects
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CRYSTAL grain boundaries , *THERMOELECTRIC materials , *THERMAL conductivity , *SEEBECK coefficient , *CARRIER density , *PHONON scattering , *CHARGE carrier mobility - Abstract
• Angle of grain boundaries converts to low from high by electrostatic force. • Low energy of low-angle grain boundary scatters carrier but not phonon. • Pulse current treatment provides a method to get high power factor and power density. Current applications of thermoelectric (TE) materials are limited by their low conversion efficiency. Interfacial engineering is a common way to improve TE properties. This study employed a pulsed electric field to tune the grain interfacial structure of Bi 2 Te 3 films and thereby improve their power factor. The high-angle grain boundaries of the as-deposited films were transformed into low-angle grain boundaries (LAGBs) by the electrostatic force of a high pulse current density. The low interfacial energy of LAGBs maintains high carrier mobility while their reduced defects result in a low carrier concentration. These effects improve the Seebeck coefficient and conductivity simultaneously, with the power factor reaching 5394.77 μW·m−1·K−2 at 513 K. In addition, the compression stress generated by LAGBs enhances phonon scattering, creating a film with the highest power density yet reported (1.31 W·m−2). This provides a method for using PEF to improve the performance of TE materials. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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