Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Joshua B Martin

Research Physicist

Applications using thermoelectric materials, materials that interconvert thermal and electrical energy, include waste heat recovery in engines for automotive, aerospace, and military applications, and solid-state refrigeration for consumer products and microelectronics. The Seebeck coefficient is an essential indicator of the conversion efficiency and the most widely measured property specific to these materials. However, the intra- and inter-laboratory comparison of Seebeck coefficient measurements has highlighted conflicting data, due to the diversity of instrumentation and the lack of standardized measurement protocols and certified reference materials. To elucidate the influence of these factors in the measurement of the Seebeck coefficient at high temperature and to identify standard testing protocols, Dr. Martin has developed a custom high temperature (300 K – 1200 K) thermoelectric measurement apparatus, which is uniquely capable of in situ comparison of commonly applied probe arrangements and measurement techniques. With the goal of accelerating the development of more efficient thermoelectric materials and devices, he has also completed a comprehensive analysis of 200 years of thermoelectric measurement literature, thereby creating a resource for best measurement practices in the form of a widely accessible review paper. Additionally, he has development a novel finite element analysis approach to simulate and model Seebeck coefficient measurements for the first time, thus enabling the quantification of errors that were previously experimentally inaccessible.

Dr. Martin graduated from the University of South Florida with a Ph.D. in Applied Physics in 2008 and then was awarded a NRC Research Associateship at NIST. He is currently leading the project “Measurements, Standards, and Data for Energy Conversion Materials.” We have recently introduced the NIST (National Institute of Standards and Technology) Standard Reference Material® (SRM) 3451 “Low Temperature Seebeck Coefficient Standard: 10 K - 390 K”. This has enabled researchers to calibrate Seebeck coefficient measurement instrumentation and to reliably compare data. Dr. Martin is now developing a complementary high temperature Seebeck coefficient Standard Reference Material (SRM). Dr. Martin is actively involved in the VAMAS Thermoelectric Working Group, leading the effort to identify and disseminate measurement protocols and reference materials.

Opportunities for a NRC Postdoctoral Fellow exist to investigate fundamental material transport properties (Seebeck coefficient, electrical resistivity, heat capacity, thermal diffusivity) by developing new measurement techniques and improved measurement instrumentation, to investigate the synthesis of novel materials using both traditional and combinatorial approaches, and to develop advanced manufacturing techniques for thermoelectric modules. Opportunities also exist for other energy storage and conversion technologies, including storage devices such as batteries, and transduction technologies that convert energy from a form that is challenging to store into one that is economically favorable or more convenient, including for example, chemical, kinetic, electrostatic, or thermal. More information on this opportunity are available here.

Research Interests

  • Develop advanced metrology techniques and apparatus to characterize transport properties of thermoelectric and other energy conversion materials
  • Investigate the structure-property relationships of novel energy conversion materials
  • Inorganic materials of interest: functional nanocomposites, open-structured frameworks, and combinatorial films
  • Develop new techniques to characterize the thermal properties of materials at high temperature

 Selected Publications Prior to Joining NIST

  • J. Martin, G. S. Nolas, H. Wang, Optimization of the thermoelectric properties of Ba8Ga16Ge30, Appl. Phys. Lett., 92, 222110 (2008).
  • J. Martin, G. S. Nolas, H. Wang, J. Yang, Thermoelectric Properties of Silicon-Germanium Type I Clathrates, J. Appl. Phys. 102, 103719 (2007).
  • J. Martin, G. S. Nolas, W. Zhang, and L. Chen, PbTe nanocomposites synthesized from PbTe nanocrystals, Appl. Phys. Lett. 90, 222112 (2007).

 

Awards

  • 2014 Department of Commerce Bronze Medal Award: “For development of Seebeck coefficient metrologies and standards that advance the commercialization of thermoelectric energy conversion materials.”
  • 2013 International Centre for Diffraction Data annual meeting best poster award
  • Fall 2008 National Research Council Postdoctoral Fellowship at NIST, Gaithersburg, MD
  • Summer 2007 Summer Research Fellowship, Department of Physics, USF
  • Spring 2007 Graduate Publication Award, College of Arts and Sciences, USF
  • Spring 2006 Fred L. and Helen M. Tharp Physics Graduate Scholarship, USF
  • Summer 2005 General Motors R&D Internship, Warren, MI
  • Fall 2003 Student Poster Award, Symposium S, Materials Research Society Fall Meeting, Boston, MA

Publications

Structural, chemical, electrical and thermal properties of n-type NbFeSb

Author(s)
Dean Hobbis, Raphael P. Hermann, Hsin Wang, David S. Parker, Tribhuwan Pandey, Joshua B. Martin, Katharine L. Page, George S. Nolas
We report on the structural, chemical, electrical and thermal properties of n-type polycrystalline NbFeSb synthesized by induction melting of the elements
Created October 9, 2019