Defect‐Controlled Electronic Properties in AZn2Sb2 Zintl Phases

Pomrehn, Gregory; Zevalkink, Alex; Zeier, Wolfgang G.; Walle, Axel van de; Snyder, G. Jeffrey

doi:10.1002/ange.201311125

Cited by 33 publications

(31 citation statements)

References 42 publications

(52 reference statements)

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“…In Zintl compounds with the chemical formula AZn 2 Sb 2 (A = Sr, Ca, Eu, Yb), the cation was found to play an important role in determining the stable concentration of A vacancies, thus determining the p-type carrier concentration at room temperature. 33 SrZn 2 Sb 2 was found to have the lowest hole concentration among compounds in that system. Among A 5 Al 2 Sb 6 compounds, we find that the Sr analogue also has fewer holes (<2 × 10 18 holes per cm 3 ) than the Ca-based compounds (>5 × 10 18 holes per cm 3 ), perhaps due to a similar mechanism.…”

Section: Electronic Transportmentioning

confidence: 89%

“…For example, in AZn 2 Sb 2 semiconducting compounds, the A species controls the hole concentration of the pure compound by influencing the equilibrium defect concentration. 33 The current study employs a combination of high temperature transport measurements and density functional theory to investigate the intrinsic thermoelectric properties of Sr 5 Al 2 Sb 6 and the effect of substituting Zn 2+ on the Al 3+ site.…”

Section: Introductionmentioning

confidence: 99%

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Thermoelectric Properties and Electronic Structure of the Zintl‐Phase Sr₃AlSb₃

et al. 2013

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The Zintl phase Sr 5 Al 2 Sb 6 has a large, complex unit cell and is composed of relatively earth-abundant and non-toxic elements, making it an attractive candidate for thermoelectric applications. The structure of Sr 5 Al 2 Sb 6 is characterized by infinite oscillating chains of AlSb 4 tetrahedra. It is distinct from the structure type of the previously studied Ca 5 M 2 Sb 6 compounds (M = Al, Ga or In), all of which have been shown to have promising thermoelectric performance. The lattice thermal conductivity of Sr 5 Al 2 Sb 6 (∼0.55 W mK −1 at 1000 K) was found to be lower than that of the related Ca 5 M 2 Sb 6 compounds due to its larger unit cell (54 atoms per primitive cell). Density functional theory predicts a relatively large band gap in Sr 5 Al 2 Sb 6 , in agreement with the experimentally determined band gap of E g ∼ 0.5 eV. High temperature electronic transport measurements reveal high resistivity and high Seebeck coefficients in Sr 5 Al 2 Sb 6 , consistent with the large band gap and valence-precise structure. Doping with Zn 2+ on the Al 3+ site was attempted, but did not lead to the expected increase in carrier concentration. The low lattice thermal conductivity and large band gap in Sr 5 Al 2 Sb 6 suggest that, if the carrier concentration can be increased, thermoelectric performance comparable to that of Ca 5 Al 2 Sb 6 could be achieved in this system.

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Section: Electronic Transportmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Thermoelectric Properties and Electronic Structure of the Zintl‐Phase Sr₃AlSb₃

et al. 2013

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“…Slack, shows that an efficient thermoelectric material should exhibit low thermal conductivity as that in a glass but high electricity as that in a well-ordered crystal. Based on the PGEC concept, various good TE materials with high zTs have been reported, including filled skutterdites, 8,9 zintl phases, 10,11 and clathrates. 12,13 Recently, the PGEC concept is further extended to superionic conductors within a name of phonon-liquid electron-crystal (PLEC).…”

Section: Introductionmentioning

confidence: 99%

Thermoelectric properties of Cu₂Se_1−xTe_x solid solutions

et al. 2018

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Binary Cu 2 Se and Cu 2 Te have gained a great attention recently because of their interesting and abnormal physical properties, such as ultralow thermal conductivity, high carrier mobility, large effective mass of carriers and excellent thermoelectric performance. In this study, we find these two compounds are completely miscible throughout the studied composition range. The trigonal structure of Cu 2 Se is maintained when the Te content x is 0.2, but a new trigonal structure is formed when the Te content x is between 0.3 and 0.7. The carrier concentration is greatly improved when increasing the Te content in Cu 2 Se 1-x Te x solid solutions, resulting in much reduced electrical resistivity and Seebeck coefficient in the whole temperature range as compared with those of binary Cu 2 Se. The total thermal conductivity is inversely increased due to the contribution from enhanced carrier thermal conductivity. As a result, the overall thermoelectric performance of Cu 2 Se 1-x Te x solid solutions lies between Cu 2 Se and Cu 2 Te. We also find that the quality factor of Cu 2 Se 1-x Te x is higher than most typical thermoelectric materials. Thus, the thermoelectric performance can be further improved if the intrinsically high hole carrier concentrations can be reduced in Cu 2 Se 1-x Te x .

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“…Many well-known Zintl phases, such as Ca 5 Al 2 Sb 6 and CaZn 2 Sb 2 are examples of materials where cation vacancies act as "killer" defects to limit n-type doping. 30 Conversely, the absence of acceptor defects with low formation energy presents an opportunity for n-type doping. Analogous arguments can be drawn for the role of native donor defects in p-type dopability.…”

Section: Defect Chemistry Of P-type Zintl Pnictidesmentioning

confidence: 99%