Enhancing the thermoelectric performance of Sb2Si2Te6 by germanium doping

Lu, Xiaowei; Sun, Lin; Luo, Jipeng; Shi, Quan; Ta, Na; Jiang, Peng; Bao, Xinhe

doi:10.1039/d2ta05287c

Cited by 13 publications

(5 citation statements)

References 47 publications

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“…It should be pointed out that the increase in carrier concentration will generally enhance carrier scattering, resulting in a decrease in mobility. , The simultaneous increase of the mobility and carrier concentration in (CuAg) 1.02 Se with Zn doping seems to be impossible. However, the carrier concentration of CuAgSe is obtained from the Hall coefficient( R H = 1/ n H ); hence, n H is the net carrier concentration.…”

Section: Resultsmentioning

confidence: 99%

Balanced High Thermoelectric Performance in n-Type and p-Type CuAgSe Realized through Vacancy Manipulation

Yu,

Ning,

Liu

et al. 2023

ACS Appl. Mater. Interfaces

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As a liquid-like material, CuAgSe has high carrier mobility and ultralow lattice thermal conductivity. It undergoes an n–p conduction-type transition during β- to α-phase transition with increasing temperature. Moreover, optimization of the thermoelectric performance of CuAgSe is rather difficult, owing to the two-carrier conduction in this material. In this work, we reported the free tuning of the conduction type and thermoelectric performance of CuAgSe by manipulating the cation vacancies. Positron annihilation measurements reveal that the increase in CuAg content can effectively suppress the cation vacancies and reduce the hole carrier concentration, resulting in n-type conduction at high temperatures. Doping with Zn at the Cu sublattice in the CuAg-excessive CuAgSe can further decrease the number of vacancies, leading to a significant decrease in hole carrier concentration. Furthermore, the reduction of vacancies leads to weakening of carrier scattering. As a result, carrier mobility is also enhanced, thus improving the thermoelectric performance of n-type CuAgSe. On the other hand, high-performance p-type CuAgSe can be achieved by decreasing the CuAg content to introduce more cation vacancies. Ultimately, both n-type and p-type CuAgSe with superb thermoelectric performance are obtained, with a zT max of 0.84 in Cu1.01Ag1.02Zn0.01Se (n-type) and 1.05 in (CuAg)0.96Se (p-type) at 600 K and average zT of 0.77 and 0.94 between 470 and 630 K for n-type and p-type, respectively.

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Section: Resultsmentioning

confidence: 99%

Balanced High Thermoelectric Performance in n-Type and p-Type CuAgSe Realized through Vacancy Manipulation

Yu,

Ning,

Liu

et al. 2023

ACS Appl. Mater. Interfaces

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“…These power-factors are comparable with the other Si based thermoelectrics, such as nanostructured Si–Ge bulk alloys (2.1–2.4 mW m −1 K −2 ), 47,48 or Ge-doped Sb 2 Si 2 Te 6 (1.1 mW m −1 K −2 ). 49…”

Section: Resultsmentioning

confidence: 99%

“…These power-factors are comparable with the other Si based thermoelectrics, such as nanostructured Si-Ge bulk alloys (2.1-2.4 mW m À1 K À2 ), 47,48 or Ge-doped Sb 2 Si 2 Te 6 (1.1 mW m À1 K À2 ). 49 As explained above, the main advantage of using AMSET is the calculation of carrier scattering rates, therefore thermoelectric properties can be accurately computed beyond constant scattering time approximation. The computed scattering rates near the band edges are shown in Fig.…”

Section: Thermoelectric Propertiesmentioning

confidence: 99%

High thermoelectric figure of merit in p-type Mg₃Si₂Te₆: role of multi-valley bands and high anharmonicity

Pandey¹,

Peeters²,

Milošević³

2023

J. Mater. Chem. C

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“…More recently, Bi 2 Si 2 Te 6 , an analogue of Sb 2 Si 2 Te 6 , was reported to possess an optimal figure of merit with zT of ∼0.51 at 623 K . The presence of doping, strain, and point defect can further reduce κ ph to improve their thermoelectric performance. − Previous studies theoretically investigated the thermal transport and thermoelectric properties of Sb 2 Si 2 Te 6 . ,, However, these works only consider three-phonon scattering processes when calculating κ ph . Actually, acting as a common lattice, the layered X 2 Si 2 Te 6 (X = Sb and Bi) isostructural family, consisting of X 3+ cations and [Si 2 Te 6 ] 6– anions, are ideal systems to examine the fourth-phonon contribution owing to their unique structure with a mixture of semiconducting and ionic bonding units.…”

Section: Introductionmentioning

confidence: 99%

Exotic Quartic Anharmonicity Induced by Rattling Effect in Layered Isostructural Compounds

Shu,

Jia,

et al. 2024

J. Phys. Chem. C

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Anharmonicity of phonons correlates with less dispersive potential surfaces and usually governs the thermal transport of low-dimensional materials. Here, we demonstrate the significant role of the so-called “rattling” action in affecting lattice anharmonicity, originating from the ease of freedom of confined but loose atoms in two-dimensional space. Based on calculations of X2Si2Te6 (X = Sb and Bi) within the Peierls–Boltzmann framework, the degree of high-order four-phonon scattering differs strikingly despite their isostructural feature. Upon switching on four-phonon scattering, a significant drop of thermal conductivity (κph) occurs in Bi2Si2Te6 up to 43.15% (71.62%) at 300 K (1000 K), while a moderate reduction occurs for Sb2Si2Te6. This arises from a stronger quartic anharmonicity of Bi2Si2Te6 than Sb2Si2Te6, dominated by the redistribution four-phonon process (λ + λ′ → λ″ + λ‴). We show that the strong quartic anharmonicity is more likely to occur in systems with flat phonon bands, large atoms, and rattling atomic units. These new insights provide perspectives in the design of materials with low κph through introducing rattling units in layered materials or interfaces.

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Enhancing the thermoelectric performance of Sb₂Si₂Te₆ by germanium doping

Abstract: Thermoelectric materials, which can directly convert the thermal energy into electricity, play an important role in the waste heat recovery. Sb2Si2Te6 is a promising medium-temperature thermoelectric material for the power...

Cited by 13 publications

References 47 publications

Balanced High Thermoelectric Performance in n-Type and p-Type CuAgSe Realized through Vacancy Manipulation

Balanced High Thermoelectric Performance in n-Type and p-Type CuAgSe Realized through Vacancy Manipulation

High thermoelectric figure of merit in p-type Mg₃Si₂Te₆: role of multi-valley bands and high anharmonicity

Exotic Quartic Anharmonicity Induced by Rattling Effect in Layered Isostructural Compounds

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Enhancing the thermoelectric performance of Sb2Si2Te6 by germanium doping

Abstract: Thermoelectric materials, which can directly convert the thermal energy into electricity, play an important role in the waste heat recovery. Sb2Si2Te6 is a promising medium-temperature thermoelectric material for the power...

Cited by 13 publications

References 47 publications

Balanced High Thermoelectric Performance in n-Type and p-Type CuAgSe Realized through Vacancy Manipulation

Balanced High Thermoelectric Performance in n-Type and p-Type CuAgSe Realized through Vacancy Manipulation

High thermoelectric figure of merit in p-type Mg3Si2Te6: role of multi-valley bands and high anharmonicity

Exotic Quartic Anharmonicity Induced by Rattling Effect in Layered Isostructural Compounds

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Enhancing the thermoelectric performance of Sb₂Si₂Te₆ by germanium doping

High thermoelectric figure of merit in p-type Mg₃Si₂Te₆: role of multi-valley bands and high anharmonicity