About

G. Jeffrey Snyder is a Professor of Materials Science & Engineering at Northwestern University. His research focuses on thermoelectric materials and devices, including the characterization and analysis of electrical and thermal interface resistance in semiconductors, grain boundary complexion engineering for high thermoelectric performance, band structure engineering, and the development of Zintl materials for thermoelectric power generation. He is involved in the synthesis, characterization, and application of nanomaterials for thermoelectrics, utilizing bulk processing methods suitable for commercialization. Professor Snyder's work also encompasses solid-state physics and thermodynamics of thermoelectric materials, predictive modeling of electronic and thermal transport properties, and hierarchical engineering principles for thermal to electric power generation and thermal management systems. His contributions include demonstrating high thermoelectric efficiency in various systems, exploring Zintl phases for thermoelectric applications, and developing microfabrication techniques for thermoelectric MEMS devices. His research aims to increase energy efficiency through waste heat recovery, thermal insulation, and cogeneration of heat and electricity.

Research topics

• Thermodynamics
• Physics
• Materials science
• Composite material
• Condensed matter physics
• Engineering
• Electrical engineering
• Mechanical engineering
• Optoelectronics
• Engineering physics
• Crystallography
• Optics
• Chemistry
• Nanotechnology
• Geometry
• Biology
• Ecology
• Mathematical analysis
• Mathematics

Selected publications

• Microscale Imaging of Thermal Conductivity Suppression at Grain Boundaries

  Advanced Materials · 2023 · 51 citations

  • Materials science
  • Composite material
  • Thermodynamics

  Grain-boundary engineering is an effective strategy to tune the thermal conductivity of materials, leading to improved performance in thermoelectric, thermal-barrier coatings, and thermal management applications. Despite the central importance to thermal transport, a clear understanding of how grain boundaries modulate the microscale heat flow is missing, owing to the scarcity of local investigations. Here, thermal imaging of individual grain boundaries is demonstrated in thermoelectric SnTe via spatially resolved frequency-domain thermoreflectance. Measurements with microscale resolution reveal local suppressions in thermal conductivity at grain boundaries. Also, the grain-boundary thermal resistance - extracted by employing a Gibbs excess approach - is found to be correlated with the grain-boundary misorientation angle. Extracting thermal properties, including thermal boundary resistances, from microscale imaging can provide comprehensive understanding of how microstructure affects heat transport, crucially impacting the materials design of high-performance thermal-management and energy-conversion devices.

  PublisherOA PDFDOI

• Distributed and localized cooling with thermoelectrics

  Joule · 2021 · 70 citations

  1st authorCorresponding
  • Engineering physics
  • Mechanical engineering
  • Engineering
  PublisherOA PDFDOI

• Thermal resistance at a twist boundary and a semicoherent heterointerface

  Physical review. B./Physical review. B · 2021 · 22 citations

  Senior authorCorresponding
  • Materials science
  • Condensed matter physics
  • Engineering physics

  Traditional models of interfacial phonon scattering, including the acoustic mismatch model and diffuse mismatch model, take into account the bulk properties of the material surrounding the interface, but not the atomic structure and properties of the interface itself. Here, we derive a theoretical formalism for the phonon scattering at a dislocation grid, or two interpenetrating orthogonal arrays of dislocations, as this is the most stable structure of both the symmetric twist boundary and semicoherent heterointerface. With this approach, we are able to separately examine the contribution to thermal resistance due to the step-function change in acoustic properties and due to interfacial dislocation strain fields, which induces diffractive scattering. Both low-angle Si-Si twist boundaries and the Si-Ge heterointerfaces are considered here and compared to previous experimental and simulation results. This work indicates that scattering from misfit dislocation strain fields doubles the thermal boundary resistance of Si-Ge heterointerfaces compared to scattering due to acoustic mismatch alone. Scattering from grain boundary dislocation strain fields is predicted to dominate the thermal boundary resistance of Si-Si twist boundaries. This physical treatment can guide the thermal design of devices by quantifying the relative importance of interfacial strain fields, which can be engineered via fabrication and processing methods, versus acoustic mismatch, which is fixed for a given interface. Additionally, this approach captures experimental and simulation trends such as the dependence of thermal boundary resistance on the grain boundary angle and interfacial strain energy.

  PublisherOA PDFDOI

• All-Inorganic Halide Perovskites as Potential Thermoelectric Materials: Dynamic Cation off-Centering Induces Ultralow Thermal Conductivity

  Journal of the American Chemical Society · 2020 · 284 citations

  • Chemistry
  • Condensed matter physics
  • Crystallography

  .

  DOI

• Expression of interfacial Seebeck coefficient through grain boundary engineering with multi-layer graphene nanoplatelets

  Energy & Environmental Science · 2020 · 146 citations

  Senior authorCorresponding
  • Materials science
  • Composite material
  • Nanotechnology

  Expression of energy filtering to boost thermoelectric performance through grain boundary engineering utilising graphene.

  DOI

• Weighted Mobility

  Advanced Materials · 2020 · 906 citations

  1st authorCorresponding
  • Materials science
  • Condensed matter physics
  • Optoelectronics

  . Weighted mobility analysis can elucidate the electronic structure and scattering mechanisms in materials and is particularly helpful in understanding and optimizing thermoelectric systems.

  DOI

• Stretchable fabric generates electric power from woven thermoelectric fibers

  Nature Communications · 2020 · 381 citations

  Senior authorCorresponding
  • Materials science
  • Composite material
  • Optoelectronics

  for a temperature difference of 44 K and excellent stretchability (~80% strain) with no output degradation. The compatibility between body movement and sustained power supply is further displayed. The generators described here are true textiles, proving active thermoelectrics can be woven into various fabric architectures for sensing, energy harvesting, or thermal management.

  DOI

Recent grants

• DMREF: Collaborative Research: Accelerating Thermoelectric Materials Discovery via Dopability Predictions

  NSF · $384k · 2017–2023

Frequent coauthors

• Umut Aydemir

  127 shared

• Heng Wang

  Anhui University of Science and Technology

  104 shared

• Eric S. Toberer

  95 shared

• Zachary M. Gibbs

  California Institute of Technology

  83 shared

• Guodong Li

  71 shared

• Yu Pan

  Chongqing University

  66 shared

• Stephen Dongmin Kang

  64 shared

• Alex Zevalkink

  63 shared

Labs

• Snyder LabPI

Education

• Ph. D., Applied Physics

  Stanford University

  1997

• Visiting Researcher, Abteilung Simon

  Max-Planck-Institut für Festkörperforschung

  1993

• BS, Chemistry, Physics, Mathematics

  Cornell University

  1991

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