Enhanced Seebeck coefficient through energy-barrier scattering in PbTe nanocomposites

Martin, Joshua; Wang, Li; Chen, Lidong; Nolas, George S.

doi:10.1103/physrevb.79.115311

Cited by 415 publications

(320 citation statements)

References 31 publications

(44 reference statements)

Supporting

Mentioning

295

Contrasting

Order By: Relevance

“…This is an important difference to bulk , the pellets of nanoplatelets show a positive ∆σ/∆T ratio. This behaviour has recently been predicted by Nolas and co-workers [26] for where the negative ∆σ/∆T ratio forces a maximum in ZT at 50…”

supporting

confidence: 77%

ZT Enhancement in Solution-Grown Sb_(2−x)Bi_xTe₃ Nanoplatelets

et al. 2010

View full text Add to dashboard Cite

We report a solution-processed, ligand supported synthesis of 15-20 nm thick Sb (2−x) BixTe3 nanoplatelets. After complete ligand removal by a facile NH3-based etching procedure, the platelets are spark plasma sintered to a p-type nanostructured bulk material with preserved crystal grain sizes. Due to this nanostructure, the total thermal conductivity is reduced by 60 % in combination with a reduction in electric conductivity of as low as 20 % as compared to the bulk material demonstrating the feasibility of the phonon-glass electron-crystal concept. An enhancement in the dimensionless thermoelectric figure of merit of up to 15 % over state-of-the-art bulk materials is achieved meanwhile shifting the maximum to significantly higher temperatures.Recently, Bi 2 Te 3 based nanostructured materials have received great attention due to their outstanding thermoelectric properties. From the first reports in the 1950s until today, the dimensionless thermoelectric figure of merit (ZT) of such materials at room temperature has been improved threefold. ZT is estimated to require a value of 3 to be competitive with conventional cooling devices and to open up novel pathways for efficient and greener power generation.The record high efficiency of 2.4 was reported for molecular beam epitaxy engineered thin films of Bi 2 Te 3 /Sb 2 Te 3 layers, which may be difficult to use in large-scale applications but convincingly demonstrated the potential for further improvements to come from nanostructured Bi 2 Te 3 based materials [5].In order to fabricate such materials on a macroscopic scale, one conventionally applies high pressure and suitable temperatures to sinter a Bi 2 Te 3 based nanopowder to a dense nanocomposite with preserved crystal grain boundaries. Such nanocomposites have been studied by the means of transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDS) [6] and scanning electron microscopy (SEM) [7]. It is believed that the unique structural details in these materials such as laminated structure, coherent interfaces, nanoprecipitates with defect concentrations and broad size distribution of crystalline domains effect all three parameters of ZT, namely the thermopower, electric and * Electronic address: scheele@chemie.uni-hamburg.de thermal conductivity and can lead to an overall improvement of thermoelectric efficiency.Synthetic strategies to Bi 2 Te 3 based nanopowders can be divided into two approaches: (a) ligandless or (b) ligand supported nanograin growth. Advantages of the former are the absence of organic impurities and the good alloying possibilities by standard semiconductor manipulations. As a matter of this, the ligandless approach was more successful recently and all of the mile stone achievements in enhancing zT as cited above were due this strategy. An instructive summary has been provided recently by Ren and coworkers [8]. However, it is found almost impossible to achieve a good size control and narrow size distribution of nanoparticles by this strategy. This is the major advan...

show abstract

supporting

confidence: 77%

ZT Enhancement in Solution-Grown Sb_(2−x)Bi_xTe₃ Nanoplatelets

et al. 2010

View full text Add to dashboard Cite

show abstract

“…This originates probably due to energy dependent scattering of carriers, leading to an energy filtering effect that enhances the Seebeck coefficient [33]. Similar trend was also observed in Pt-Sb2Te3 [34] and PbTe nanocomposites [35]. of Cu2-yX (X= S, Se, and Te) matrix compounds [10,29,30], Cu2Se1-xSx [24] and Cu2S1-xTex [9] solid solutions are also given.…”

Section: Electrical Transport Propertiesmentioning

confidence: 53%

High thermoelectric performance and low thermal conductivity in Cu2−yS1/3Se1/3Te1/3 liquid-like materials with nanoscale mosaic structures

et al. 2017

Self Cite

View full text Add to dashboard Cite

Mosaic-crystal microstructure is one of the optimal strategies for decoupling and balancing thermal and electrical transport properties in thermoelectric materials. Herein, we successfully achieve the desired nanoscale mosaic structures in triple-component Cu2-yS1/3Se1/3Te1/3 solid solutions using Cu2S, Cu2Se, and Cu2Te matrix compounds. They are solved in hexagonal structures with space group R3 ̅ m by means of single crystal structural solution and Rietveld refinement. Electron backscatter diffraction measurements show that all the samples are polycrystalline compounds with the grain size in the range of micrometers. However, transmission electron microscopic study reveals that these microscale grains are quasi-single crystals consist of a variety of 10-30 nm mosaic grains. Each mosaic grain is a perfect crystal but titled or rotated with respect to others by a very small angle. In this case, excellent electrical transports are maintained but exceptional low thermal conductivity is achieved throughout the whole temperature range, which is attributed to the combined phonon scatterings by point defects, liquid-like copper ions, and lattice strains or interfaces of mosaic nanograins. Combining all these favorable factors, remarkably high thermoelectric performance is achieved in Cu1.98S1/3Se1/3Te1/3 2 with a maximum zT of 1.9 at 1000 K.

show abstract

“…56 Energy-barrier scattering is conceptually similar to the scattering by ionised impurities; both processes scatter low-energy carriers more effectively than the high energy ones, but the implementation is different. The beneficial effect of energy barriers can be found in the systems having a semiconducting host matrix and metallic composites or nano-inclusions, such as the pristine PbTe matrix containing Ag-doped PbTe nanoparticles, 57 semimetallic ErAs particles in InGaAs/InGaAlAs superlattices, 58,59 and half-Heusler compounds with full-Heusler metallic inclusions (Figure 3a). 60,61 Another possible beneficial scheme relating to the interface between matrix and nanostructure is the modulation doping and δ-doping techniques.…”

Section: Manipulation Of Carrier Scatteringmentioning

confidence: 99%

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

et al. 2016

Self Cite

View full text Add to dashboard Cite

During the last two decades, we have witnessed great progress in research on thermoelectrics. There are two primary focuses. One is the fundamental understanding of electrical and thermal transport, enabled by the interplay of theory and experiment; the other is the substantial enhancement of the performance of various thermoelectric materials, through synergistic optimisation of those intercorrelated transport parameters. Here we review some of the successful strategies for tuning electrical and thermal transport. For electrical transport, we start from the classical but still very active strategy of tuning band degeneracy (or band convergence), then discuss the engineering of carrier scattering, and finally address the concept of conduction channels and conductive networks that emerge in complex thermoelectric materials. For thermal transport, we summarise the approaches for studying thermal transport based on phonon-phonon interactions valid for conventional solids, as well as some quantitative efforts for nanostructures. We also discuss the thermal transport in complex materials with chemical-bond hierarchy, in which a portion of the atoms (or subunits) are weakly bonded to the rest of the structure, leading to an intrinsic manifestation of part-crystalline part-liquid state at elevated temperatures. In this review, we provide a summary of achievements made in recent studies of thermoelectric transport properties, and demonstrate how they have led to improvements in thermoelectric performance by the integration of modern theory and experiment, and point out some challenges and possible directions. INTRODUCTION Thermoelectric (TE) materials are materials that can generate useful electric potentials when subjected to a temperature gradient (known as the Seebeck effect). Conversely, they also transfer heat against the temperature gradient when a current is driven against this potential (known as the Peltier effect). They are promising energy materials with many applications, such as waste heat harvesting, radioisotope TE power generation, and solid state Peltier refrigeration, all of which are driving growing research interest. A key challenge is to improve the TE properties in order to obtain more efficient energy conversion and in turn enable new practical applications. Good TE materials must have excellent electrical transport properties, measured by the TE power factor ( = S 2 σ, where S is the Seebeck coefficient and σ is the electrical conductivity), and also a very low thermal conductivity κ (composed of the electronic contribution κ e , the lattice contribution κ L , and the bipolar contribution κ bi ). Combining the two aspects gives us the dimensionless figure of merit ZT,

show abstract

Enhanced Seebeck coefficient through energy-barrier scattering in PbTe nanocomposites

Cited by 415 publications

References 31 publications

ZT Enhancement in Solution-Grown Sb_(2−x)Bi_xTe₃ Nanoplatelets

ZT Enhancement in Solution-Grown Sb_(2−x)Bi_xTe₃ Nanoplatelets

High thermoelectric performance and low thermal conductivity in Cu2−yS1/3Se1/3Te1/3 liquid-like materials with nanoscale mosaic structures

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

Contact Info

Product

Resources

About

Enhanced Seebeck coefficient through energy-barrier scattering in PbTe nanocomposites

Cited by 415 publications

References 31 publications

ZT Enhancement in Solution-Grown Sb(2−x)BixTe3 Nanoplatelets

ZT Enhancement in Solution-Grown Sb(2−x)BixTe3 Nanoplatelets

High thermoelectric performance and low thermal conductivity in Cu2−yS1/3Se1/3Te1/3 liquid-like materials with nanoscale mosaic structures

On the tuning of electrical and thermal transport in thermoelectrics: an integrated theory–experiment perspective

Contact Info

Product

Resources

About

ZT Enhancement in Solution-Grown Sb_(2−x)Bi_xTe₃ Nanoplatelets

ZT Enhancement in Solution-Grown Sb_(2−x)Bi_xTe₃ Nanoplatelets