Thermal investigation of nanostructured bulk thermoelectric materials with hierarchical structures: An effective medium approach
Abstract
In recent years, hierarchical structures have been intensively studied as an effective approach to tailor the electron and phonon transport inside a bulk material for thermoelectric applications. With atomic defects and nano- to micro-scale structures in a bulk material, the lattice thermal conductivity can be effectively suppressed across the whole phonon spectrum, while maintaining or somewhat enhancing the electrical properties. For general materials with superior electrical properties, high thermoelectric performance can be achieved using hierarchical structures to minimize the lattice thermal conductivity. Despite many encouraging experimental results, accurate lattice thermal conductivity predictions are still challenging for a bulk material with hierarchical structures. In this work, an effective medium formulation is developed for nanograined bulk materials with embedded nanostructures for frequency-dependent phonon transport analysis. This new formulation is validated with frequency-dependent phonon Monte Carlo simulations. For high-temperature thermoelectric applications, nanograined bulk ZnO with embedded GaN nanoparticles is studied with the formulation.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 03, 2018
- Source ID
- 10.1063/1.5006207
Entities
People
- Dongchao Xu
- Hongbo Zhao
- Qing Hao
- Yue Xiao
Organizations
- Air Force Office of Scientific Research
- National Science Foundation
- University of Arizona