Embedded Ag-rich nanodots in PbTe: Enhancement of thermoelectric properties through energy filtering of the carriers

Paul, Biplab; Kumar, Ajay; Banerji, P.

doi:10.1063/1.3488621

Cited by 102 publications

(68 citation statements)

References 15 publications

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“…4 The PbTe/Ag nanocomposite with embedded Ag-rich nanodots in the PbTe has the highest power factor of 18.78 lW cm -1 K -2 at 350 K, which can be ascribed to carrier energy filtering. 5 Recently, attention has been paid to lanthanide element doping in PbTe to improve its thermoelectric properties. Lanthanide elements in PbTe are expected to be effective donors because of their trivalent character and may strongly affect the electrical and thermal transport properties.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ce-Doping on Thermoelectric Properties in PbTe Alloys Prepared by Spark Plasma Sintering

Wang

et al. 2011

Journal of Elec Materi

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Ce-doped Pb 1Àx Ce x Te alloys with x = 0, 0.005, 0.01, 0.015, 0.03, and 0.05 were prepared by induction melting, ball milling, and spark plasma sintering techniques. The structure and thermoelectric properties of the samples were investigated. X-ray diffraction (XRD) analysis indicated that the samples were of single phase with NaCl-type structure for x less than 0.03. The lattice parameter a increases with increasing Ce content. The lower Ce-doped samples (x = 0.005 and 0.01) showed p-type conduction, whereas the pure PbTe and the higher doped samples (x = 0, 0.015, 0.03, and 0.05) showed n-type conduction. The lower Ce-doped samples exhibited a much higher absolute Seebeck coefficient, but the higher electrical resistivity and higher thermal conductivity compared with pure PbTe resulted in a lower figure of merit ZT. In contrast, the higher Ce-doped samples exhibited a lower electrical resistivity, together with a lower absolute Seebeck coefficient and comparable thermal conductivity, leading to ZT comparable to that of PbTe. The lowest thermal conductivity (range from 0.99 W m À1 K À1 at 300 K to 0.696 W m À1 K À1 at 473 K) was found in the alloy Pb 0.95 Ce 0.05 Te due to the presence of the secondary phases, leading to a ZT higher than that of pure PbTe above 500 K. The maximum figure of merit ZT, in the alloy Pb 0.95 Ce 0.05 Te, was 0.88 at 673 K.

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Section: Introductionmentioning

confidence: 99%

Effect of Ce-Doping on Thermoelectric Properties in PbTe Alloys Prepared by Spark Plasma Sintering

Wang

et al. 2011

Journal of Elec Materi

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“…There are several recently reported claims of observing energy-filtering effects but these claims are limited to only small enhancements in the power factors. The main evidence for observing energy filtering is the observation of 40 an enhanced Seebeck coefficient compared to that of the host matrix 122,123 . It should be noted that the relaxation times τ change when nanostructures are added, and as a result the Seebeck coefficient of the nanostructures are not directly comparable to those of the host matrix.…”

Section: Strategies For the Next Generation Of Nanocompositesmentioning

confidence: 99%

Perspectives on thermoelectrics: from fundamentals to device applications

Zebarjadi

Esfarjani

Dresselhaus

et al. 2012

Energy Environ. Sci.

1,193

776

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aThis review is an update of a previous review 1 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, 5 strategies to improve 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 10 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, an efficiency measurements platform, and identifying applications are becoming increasingly important for the future of thermoelectrics.15

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“…shiing of the Fermi level, creating local band resonant states, facilitating the convergence of valence band or conduction bands, inducing high effective mass and interface energy ltering effect which are usually helpful to improve the electronic properties. [17][18][19][20][21] Apart from the improvement of electronic properties, these strategies are also helpful to impede the propagation of thermal phonons by enhancing interface phonon scattering together with creating local structural disorder to increase the frequency of phonon scattering processes as well. Based on these strategies many materials such as Bi 2 Te 3 , [22][23][24][25][26] LAST, 27 TAGS, 28 PbTe 29, 30 SiGe 31,32 b-phase hexagonal structure (space group P 3m1; no.…”

Section: Introductionmentioning

confidence: 99%

Graphene boosts thermoelectric performance of a Zintl phase compound

et al. 2015

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The concept of nanocomposites derived by incorporating a second minor phase in bulk thermoelectric materials has established itself as an effective paradigm for optimizing high thermoelectric performance.In this work, this paradigm is for the first time extended to bulk Zintl phase Mg 3 Sb 2 and its isoelectronically Bi-doped derivative Mg 3 Sb 1.8 Bi 0.2 system. Herein, we report the synthesis, microstructural details, electronic structure and thermoelectric properties of (Mg 3 Sb 2 , Mg 3 Sb 1.8 Bi 0.2 )/ graphene nanosheet (GNS) nanocomposites with different mass ratios. Field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) investigation reveals that Mg 3 Sb 2 nanoparticles are homogenously anchored on the surface of GNS. We demonstrate that Mg 3 Sb 2 -based materials incorporated with a small content of graphene outperform optimally, resulting in potential ptype thermoelectric materials. The present nanocomposite additive of GNS deriving such a novel nanocomposite of (Mg 3 Sb 2 , Mg 3 Sb 1.8 Bi 0.2 )/GNS, enhances the electrical conductivity significantly, thereby resulting in a substantially large increase in the power factor. The enhanced electrical conductivity of these nanocomposites is attributed to the increase in the carrier concentration and high carrier mobility owing to the ultra high mobility of graphene. X-ray photoelectron spectroscopy (XPS) core level spectra confirm weak bonding between GNS and Mg 3 Sb 2 . Increase in carrier concentration is reflected in XPS valence band spectra and change in spectral weight near valence band maxima is indicative of increased electrical conductivity in the nanocomposite material. The thermal conductivity of these nanocomposites is noted to be reduced at high temperature. These favorable conditions lead to enhanced thermoelectric figure-of-merit (ZT) z 0.71 at 773 K for Mg 3 Sb 2 /GNS and a ZT z 1.35 at 773 K for Mg 3 Sb 1.8 Bi 0.2 /GNS nanocomposites with the mass ratio of 80 : 1 which are $170% and $125% higher values compared to bare Mg 3 Sb 2 and bare Mg 3 Sb 1.8 Bi 0.2 respectively. We strongly believe that the present novel strategy of fabricating such a nanocomposite of a Zintl compound by utilizing GNS as a nanocomposite additive, may provide an emerging path for improving thermoelectric properties of various Zintl phase compounds.

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Embedded Ag-rich nanodots in PbTe: Enhancement of thermoelectric properties through energy filtering of the carriers

Cited by 102 publications

References 15 publications

Effect of Ce-Doping on Thermoelectric Properties in PbTe Alloys Prepared by Spark Plasma Sintering

Effect of Ce-Doping on Thermoelectric Properties in PbTe Alloys Prepared by Spark Plasma Sintering

Perspectives on thermoelectrics: from fundamentals to device applications

Graphene boosts thermoelectric performance of a Zintl phase compound

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