Revealing nano-chemistry at lattice defects in thermoelectric materials using atom probe tomography

Yu, Yuan; Zhou, Chenyang; Zhang, Siyuan; Zhu, Min; Wuttig, Matthias; Scheu, Christina; Raabe, Dierk; Snyder, G. Jeffrey; Gault, Baptiste; Cojocaru‐Mirédin, Oana

doi:10.1016/j.mattod.2019.11.010

Cited by 83 publications

(74 citation statements)

References 216 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We thus employed atom probe tomography (APT) to reveal the distribution and concentration of constituent elements at the atomic scale. [ 70–72 ] Figure 2 a shows a homogeneous distribution of Ge, Sb, and Te in 3D space. The composition profile along the z ‐axis further proves the homogeneity of composition and an average bulk composition close to the nominal Ge 0.9 Sb 0.1 Te (Figure 2b).…”

Section: Resultsmentioning

confidence: 99%

“…Since the grain size (≈10 µm) is much larger than the field of view of APT probed volume (50 nm in diameter and 300 nm in length), we could not include the grain boundary in the APT characterization with several measurements. Given the extremely high elemental sensitivity of APT (normally tens ppm level for semiconductors), [ 70 ] we can conclude that boron is not dissolved into the grain interior but primarily impacts the grain boundary properties.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density

Bai

et al. 2021

Advanced Energy Materials

Self Cite

View full text Add to dashboard Cite

High‐performance thermoelectric (TE) devices require not only a high figure of merit (ZT) but also mechanical strength and thermal stability. Here, a simultaneous enhancement of ZT as well as mechanical properties is obtained in GeTe‐based alloys by adding boron. This material is then assembled with n‐type CoSb3 skutterudite into TE modules. The improved ZT values result from the increase in charge carrier mobility due to the reduced interfacial barrier height. A peak ZT of 2.2 at 773 K can be achieved in Ge0.84Pb0.1Sb0.06TeB0.07, which shows a negligible change in the coefficient of thermal expansion upon the phase transition from the rhombohedral to the cubic phase, ensuring good thermal stability of the device. Resulting from the boron‐induced grain refinement and dispersion strengthening, the average compressive strength and Vickers hardness of Ge0.9Sb0.1TeB0.07 can be enhanced to ≈227 MPa and ≈202 Hv, respectively. The improved mechanical properties facilitate the assembly of devices and lower the interfacial contact resistance. As a synergy of increased ZT and mechanical strength, a high output power density of ≈1.76 W cm−2 at ΔT = 425 K and an energy conversion efficiency of 7.4% at ΔT = 477 K can be achieved in the TE modules.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density

Bai

et al. 2021

Advanced Energy Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…To spatially determine the distribution and composition of surface SnO x , we conducted APT analysis on the untreated SnSe sample. It quantitatively provides the three-dimensional distribution of constituent elements with equal sensitivity at a spatial resolution nearly down to the subatomic level, thereby serving as an effective tool to resolve secondary phases either in the matrix or trapped at GBs [18][19][20] . Figure 3f displays the three-dimensional reconstruction of the needle-shaped specimen from the untreated SnSe sample.…”

Section: Analysis Of Surface Snomentioning

confidence: 99%

Polycrystalline SnSe with a thermoelectric figure of merit greater than the single crystal

et al. 2021

Self Cite

View full text Add to dashboard Cite

Thermoelectric materials generate electric energy from waste heat, with conversion efficiency governed by the dimensionless figure of merit, ZT. Single-crystal tin selenide (SnSe) was discovered to exhibit a high ZT of roughly 2.2–2.6 at 913 K, but more practical and deployable polycrystal versions of the same compound suffer from much poorer overall ZT, thereby thwarting prospects for cost-effective lead-free thermoelectrics. The poor polycrystal bulk performance is attributed to traces of tin oxides covering the surface of SnSe powders, which increases thermal conductivity, reduces electrical conductivity and thereby reduces ZT. Here, we report that hole-doped SnSe polycrystalline samples with reagents carefully purified and tin oxides removed exhibit an ZT of roughly 3.1 at 783 K. Its lattice thermal conductivity is ultralow at roughly 0.07 W m–1 K–1 at 783 K, lower than the single crystals. The path to ultrahigh thermoelectric performance in polycrystalline samples is the proper removal of the deleterious thermally conductive oxides from the surface of SnSe grains. These results could open an era of high-performance practical thermoelectrics from this high-performance material.

show abstract

“…Good TE materials could particularly be the case since they always need to be alloyed or doped to tune the electrical and thermal properties for high performance, which unavoidably leads to complicated microstructures [ 8 , 182 , 183 ]. Hence, a deep microstructure analysis to know the grain boundary region better with advanced techniques is highly necessary [ 184 , 185 ]. For n -type Mg 3 Sb 2 polycrystalline samples, the grain boundary phase is found to be a 10 nm region with Mg deficiency [ 98 ], resulting in the high electrical resistance.…”

Section: Optimization Of Te Propertiesmentioning

confidence: 99%

High-Performance Mg ₃ Sb _{2-
x} Bi _x Thermoelectrics: Progress and Perspective

Zhao

et al. 2020

Research

View full text Add to dashboard Cite

Since the first successful implementation of n-type doping, low-cost Mg3Sb2-xBix alloys have been rapidly developed as excellent thermoelectric materials in recent years. An average figure of merit zT above unity over the temperature range 300–700 K makes this new system become a promising alternative to the commercially used n-type Bi2Te3-xSex alloys for either refrigeration or low-grade heat power generation near room temperature. In this review, with the structure-property-application relationship as the mainline, we first discuss how the crystallographic, electronic, and phononic structures lay the foundation of the high thermoelectric performance. Then, optimization strategies, including the physical aspects of band engineering with Sb/Bi alloying and carrier scattering mechanism with grain boundary modification and the chemical aspects of Mg defects and aliovalent doping, are extensively reviewed. Mainstream directions targeting the improvement of zT near room temperature are outlined. Finally, device applications and related engineering issues are discussed. We hope this review could help to promote the understanding and future developments of low-cost Mg3Sb2-xBix alloys for practical thermoelectric applications.

show abstract

Revealing nano-chemistry at lattice defects in thermoelectric materials using atom probe tomography

Cited by 83 publications

References 216 publications

Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density

Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density

Polycrystalline SnSe with a thermoelectric figure of merit greater than the single crystal

High-Performance Mg ₃ Sb _{2-
x} Bi _x Thermoelectrics: Progress and Perspective

Contact Info

Product

Resources

About

Revealing nano-chemistry at lattice defects in thermoelectric materials using atom probe tomography

Cited by 83 publications

References 216 publications

Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density

Boron Strengthened GeTe‐Based Alloys for Robust Thermoelectric Devices with High Output Power Density

Polycrystalline SnSe with a thermoelectric figure of merit greater than the single crystal

High-Performance Mg 3 Sb 2- x Bi x Thermoelectrics: Progress and Perspective

Contact Info

Product

Resources

About

High-Performance Mg ₃ Sb _{2-
x} Bi _x Thermoelectrics: Progress and Perspective