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Author

Mona Zebarjadi

Bio: Mona Zebarjadi is an academic researcher from University of Virginia. The author has contributed to research in topics: Thermoelectric effect & Seebeck coefficient. The author has an hindex of 29, co-authored 95 publications receiving 4800 citations. Previous affiliations of Mona Zebarjadi include Rutgers University & Massachusetts Institute of Technology.


Papers
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Journal ArticleDOI
TL;DR: In this article, Minnich et al. reviewed the progress made in thermoelectrics over the past two years on charge and heat carrier transport, strategies to improve the thermiolectric figure of merit, with new discussions on device physics and applications.
Abstract: This review is an update of a previous review (A. J. Minnich, et al., Energy Environ. Sci., 2009, 2, 466) published two years ago by some of the co-authors, focusing on progress made in thermoelectrics over the past two years on charge and heat carrier transport, strategies to improve the thermoelectric figure of merit, with new discussions on device physics and applications, and assessing challenges on these topics. Understanding of phonon transport in bulk materials has advanced significantly as the first-principles calculations are applied to thermoelectric materials, and experimental tools are being developed. Some new strategies have been developed to improve electron transport in thermoelectric materials. Fundamental questions on phonon and electron transport across interfaces and in thermoelectric materials remain. With thermoelectric materials reaching high ZT values well above one, the field is ready to take a step forward and go beyond the materials' figure of merit. Developing device contacts and module fabrication techniques, developing a platform for efficiency measurements, and identifying applications are becoming increasingly important for the future of thermoelectrics.

1,049 citations

01 Jan 2012
TL;DR: In this article, Minnich et al. reviewed the progress made in thermoelectrics over the past two years on charge and heat carrier transport, strategies to improve the thermiolectric figure of merit, with new discussions on device physics and applications.
Abstract: This review is an update of a previous review (A. J. Minnich, et al., Energy Environ. Sci., 2009, 2, 466) published two years ago by some of the co-authors, focusing on progress made in thermoelectrics over the past two years on charge and heat carrier transport, strategies to improve the thermoelectric figure of merit, with new discussions on device physics and applications, and assessing challenges on these topics. Understanding of phonon transport in bulk materials has advanced significantly as the first-principles calculations are applied to thermoelectric materials, and experimental tools are being developed. Some new strategies have been developed to improve electron transport in thermoelectric materials. Fundamental questions on phonon and electron transport across interfaces and in thermoelectric materials remain. With thermoelectric materials reaching high ZT values well above one, the field is ready to take a step forward and go beyond the materials' figure of merit. Developing device contacts and module fabrication techniques, developing a platform for efficiency measurements, and identifying applications are becoming increasingly important for the future of thermoelectrics.

826 citations

Journal ArticleDOI
TL;DR: An alternative materials design is reported, using alloy Si(70) Ge(30) instead of Si as the nanoparticles and Si(95)Ge(5) as the matrix, to increase the power factor but not the thermal conductivity, leading to a ZT of 1.3 ± 0.1 at 900 °C.
Abstract: Modulation-doping was theoretically proposed and experimentally proved to be effective in increasing the power factor of nanocomposites (Si80Ge20)70(Si100B5)30 by increasing the carrier mobility but not the figure-of-merit (ZT) due to the increased thermal conductivity. Here we report an alternative materials design, using alloy Si70Ge30 instead of Si as the nanoparticles and Si95Ge5 as the matrix, to increase the power factor but not the thermal conductivity, leading to a ZT of 1.3 ± 0.1 at 900 °C.

465 citations

Journal ArticleDOI
TL;DR: The concept of modulation doping in three-dimensional nanostructured bulk materials to increase the thermoelectric figure of merit is introduced via experiment using composites made of doped silicon nanograins and intrinsic silicon germanium grains.
Abstract: We introduce the concept of modulation doping in three-dimensional nanostructured bulk materials to increase the thermoelectric figure of merit. Modulation-doped samples are made of two types of nanograins (a two-phase composite), where dopants are incorporated only into one type. By band engineering, charge carriers could be separated from their parent grains and moved into undoped grains, which would result in enhanced mobility of the carriers in comparison to uniform doping due to a reduction of ionized impurity scattering. The electrical conductivity of the two-phase composite can exceed that of the individual components, leading to a higher power factor. We here demonstrate the concept via experiment using composites made of doped silicon nanograins and intrinsic silicon germanium grains.

459 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss the ideas and strategies proposed and developed in order to improve the thermoelectric power factor and thus hopefully move us closer to the target of a ZT < 2.
Abstract: Thermoelectric research has witnessed groundbreaking progress over the past 15–20 years. The thermoelectric figure of merit, ZT, a measure of the competition between electronic transport (i.e. power factor) and thermal transport (i.e. total thermal conductivity), has long surpassed once a longtime barrier of ∼1 and thermoelectric scientists are targeting ZT > 2 as the new goal. A majority of this recent improvement in ZT has been achieved through the reduction of lattice part of thermal conductivity (κl) using nanostructuring techniques. The rapid progress in this direction focused the efforts on the development of experimental methods and understanding phonon transport to decrease lattice thermal conductivity. This fact left the development of ideas to improve electronic transport and thermoelectric power factor rather overlooked. With thermal conductivity of the potential thermoelectrics approaching the minimum theoretical limit, on the journey to higher ZT values, a paradigm shift is necessary toward the enhancement of the thermoelectric power factor. This article discusses the ideas and strategies proposed and developed in order to improve the thermoelectric power factor and thus hopefully move us closer to the target of a ZT > 2!

295 citations


Cited by
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01 Jan 2007

1,932 citations

Journal ArticleDOI
TL;DR: ShengBTE is a software package for computing the lattice thermal conductivity of crystalline bulk materials and nanowires with diffusive boundary conditions based on a full iterative solution to the Boltzmann transport equation.

1,834 citations

Journal ArticleDOI
TL;DR: In this paper, the authors introduce the principles and present status of bulk nanostructured materials, then describe some of the unanswered questions about carrier transport and how current research is addressing these questions.
Abstract: Thermoelectrics have long been recognized as a potentially transformative energy conversion technology due to their ability to convert heat directly into electricity. Despite this potential, thermoelectric devices are not in common use because of their low efficiency, and today they are only used in niche markets where reliability and simplicity are more important than performance. However, the ability to create nanostructured thermoelectric materials has led to remarkable progress in enhancing thermoelectric properties, making it plausible that thermoelectrics could start being used in new settings in the near future. Of the various types of nanostructured materials, bulk nanostructured materials have shown the most promise for commercial use because, unlike many other nanostructured materials, they can be fabricated in large quantities and in a form that is compatible with existing thermoelectric device configurations. The first generation of these materials is currently being developed for commercialization, but creating the second generation will require a fundamental understanding of carrier transport in these complex materials which is presently lacking. In this review we introduce the principles and present status of bulk nanostructured materials, then describe some of the unanswered questions about carrier transport and how current research is addressing these questions. Finally, we discuss several research directions which could lead to the next generation of bulk nanostructured materials.

1,742 citations