Nanostructured Bulk Silicon as an Effective Thermoelectric Material

Bux, Sabah K.; Blair, Richard G.; Gogna, P.; Lee, Hohyun; Chen, Gang; Dresselhaus, M. S.; Kaner, Richard B.; Fleurial, Jean‐Pierre

doi:10.1002/adfm.200900250

Cited by 477 publications

(437 citation statements)

References 43 publications

Supporting

Mentioning

399

Contrasting

Unclassified

Order By: Relevance

“…Nanotechnology has been able to greatly improve on earlier single-crystal thermoelectric materials 3 via hindering phonon flow while keeping favorable electric properties, even when starting from a poor performer such as bulk silicon. 4 Thus, it was somewhat surprising when single-crystal SnSe recently emerged as the best thermoelectric material ever measured. Experimental measurements on monocrystalline samples 5 point to a record figure of merit of ZT = 2.6 at T = 923 K. This is due mainly to its very low lattice thermal conductivity κ .…”

mentioning

confidence: 99%

Low thermal conductivity and triaxial phononic anisotropy of SnSe

Carrete

Mingo

Curtarolo

2014

Applied Physics Letters

238

201

View full text Add to dashboard Cite

In this theoretical study, we investigate the origins of the very low thermal conductivity of tin selenide (SnSe) using ab-initio calculations. We obtained high-temperature lattice thermal conductivity values that are close to those of amorphous compounds. We also found a strong anisotropy between the three crystallographic axes: one of the in-plane directions conducts heat much more easily than the other. Our results are compatible with most of the experimental literature on SnSe, and differ markedly from the more isotropic values reported by a recent study.The ongoing quest for improved thermoelectric materials has spanned the past six decades. 1,2 Good thermoelectrics are characterized by their high figures of merit ZT = P T /κ. This requires a low thermal conductivity κ, and a high power factor P = σS 2 (where σ is the electrical conductivity, and S the thermopower) across their intended range of working temperatures. Nanotechnology has been able to greatly improve on earlier single-crystal thermoelectric materials 3 via hindering phonon flow while keeping favorable electric properties, even when starting from a poor performer such as bulk silicon. 4 Thus, it was somewhat surprising when single-crystal SnSe recently emerged as the best thermoelectric material ever measured. Experimental measurements on monocrystalline samples 5 point to a record figure of merit of ZT = 2.6 at T = 923 K. This is due mainly to its very low lattice thermal conductivity κ . Intense interest in SnSe was spurred by these results, and to date two independent sets of measurements on polycrystals have been published. 6,7 The two series are compatible with each other, yet they both display higher values of κ than those reported in Ref. 5 for the single crystal. This contrasts with the expectation that grain boundaries should decrease the thermal conductivity below that of the single crystal. Remarkably, preexisting studies of single crystals 8 reported even higher values of κ, with a directional maximum of around 1.8 W m −1 K −1 at room temperature.To address this controversy, we studied phonon transport in SnSe from first principles based on the Boltzmann transport equation (BTE) formalism. Such modeling studies offer substantially more detailed information than is readily available from the experiments, and have demonstrated both their wide range of applicability and their predictive power. 9-13 For the present work, we focused on the Pnma-symmetric phase of SnSe. This is the stable phase from room temperature up to ∼ 750 − 800 K. 5 Hence, it is the pertinent phase for most of the aforementioned measurements. We started with an atomistic description of Pnma SnSe extracted from the AFLOWLIB.org consortium repository [auid=aflow:d188eb9b8df60e58]. 14,15 We relaxed the structure without any geometrical constraint using the density functional theory (DFT) software package VASP. 16 All technical details are presented in the supplementary material. We obtained unit cell lengths of a = 11.72Å, b = 4.20Å and c = 4.55Å, which are in reasonab...

show abstract

mentioning

confidence: 99%

Low thermal conductivity and triaxial phononic anisotropy of SnSe

Carrete

Mingo

Curtarolo

2014

Applied Physics Letters

238

201

View full text Add to dashboard Cite

show abstract

“…They have achieved a high ZT of 1.4 at 100°C. The same groups also reported a similar ball milling-hot pressing approach for other materials including Si-Ge alloy 16 and n-type Si, 21 among many others. Another recently developed approach is melt-spinning ribbons of the appropriate alloy, hand-grinding them, and compacting them by spark plasma sintering (SPS).…”

Section: Enhanced Zt By Nanostructuring Approachesmentioning

confidence: 90%

“…Therefore, there is an increasing amount of effort devoted to alternative thermoelectric materials that are less expensive, more abundant, and nontoxic. This trend has been facilitated by the aforementioned nanostructuring approaches that are used to enhance ZT in materials that are traditionally poor thermoelectric materials, such as Si 10,11,21 and PbSe. 22 A very promising class of Earth-abundant thermoelectric materials is based on silicide, 6 Silicide alloys are attractive for thermoelectric applications due to their low toxicity, thermal stability, low density, relative abundance, and low cost of production.…”

Section: Silicide As a Thermoelectric Materialsmentioning

confidence: 99%

See 1 more Smart Citation

Silicide Nanopowders as Low-Cost and High-Performance Thermoelectric Materials

Chen

2013

JOM

View full text Add to dashboard Cite

Thermoelectric devices directly convert heat into electricity and are very attractive for waste heat recovery and solar energy utilization. If thermoelectric devices can be made sufficiently efficient and inexpensive, then they will become a transformative energy technology that can tap a significant portion (10-20%) of the vast amount of heat existing in nature as well as industrial processes. Nanopowders of Earth-abundant, silicide-based materials, such as Mg 2 Si and its alloys, provide a unique opportunity to realize this goal. This article will present an overview of recent advances in the synthesis and thermoelectric properties of silicide-based nanostructured materials.

show abstract

“…The avenue of nanostructuring bulk silicon in order to alter the thermal transport properties was considered by Bux, 45 although the focus there was on grain control and the introduction of particulates. While such an approach leads to increased scattering and hence significant reduction in thermal conductivity, it does not provide a means of property control via dispersion.…”

Section: A Supercells: Structure and Lattice Dynamicsmentioning

confidence: 99%

Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

Davis

Hussein

2011

AIP Advances

View full text Add to dashboard Cite

The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell) and the phononic crystal lattice (defined by a supercell) contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant), dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity

show abstract

Nanostructured Bulk Silicon as an Effective Thermoelectric Material

Cited by 477 publications

References 43 publications

Low thermal conductivity and triaxial phononic anisotropy of SnSe

Low thermal conductivity and triaxial phononic anisotropy of SnSe

Silicide Nanopowders as Low-Cost and High-Performance Thermoelectric Materials

Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics

Contact Info

Product

Resources

About