Doping Effects on Thermoelectric Properties in the Mg2Sn System

Choi, Soon‐Mok; An, Tae Ho; Seo, Won‐Seon; Park, Chan; Kim, Il-Ho; Kim, Sunuk

doi:10.1007/s11664-012-1985-x

Cited by 23 publications

(7 citation statements)

References 11 publications

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“…Historically, Mg 2 Sn material has been investigated less than its analogous compound Mg 2 Si for thermoelectric applications due to its lower ZT (22)(23)(24)(25). Most of the research has been focused on the alloy of Mg 2 Si-Mg 2 Sn with a peak ZT value of ∼1 at 500°C (26)(27)(28).…”

Section: ·Kmentioning

confidence: 99%

“…Recently, different groups have improved the peak ZT value to 1.1-1.3 by adjusting the x value in the Mg 2 Si 1−x Sn x solid solution (14,29,30). The challenges in preparing and handling these materials were the high vapor pressure and chemical activity of Mg. Methods of direct comelting with subsequent annealing, and solid-state reaction with subsequent annealing and Bridgman method were reported to synthesize Mg 2 Si-Mg 2 Sn alloys (22)(23)(24)(25)(26)(27)(28)(29)(30). Powder metallurgy route, e.g., ball milling plus hot pressing, was widely used to fabricate a variety of high-performance thermoelectric bulk materials such as Bi 2 Te 3 (6,31), PbTe (32), PbSe (33), and skutterudites CoSb 3 (16,34).…”

Section: ·Kmentioning

confidence: 99%

“…A new n-type Mg 2 Sn-based material, Mg 2 Sn 0.75 Ge 0. 25 , is a good example to meet the dual requirements in efficiency and output power. It was found that Mg 2 Sn 0.75 Ge 0.…”

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n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

Liu

Kim

Chen

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

198

131

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Thermoelectric power generation is one of the most promising techniques to use the huge amount of waste heat and solar energy. Traditionally, high thermoelectric figure-of-merit, ZT, has been the only parameter pursued for high conversion efficiency. Here, we emphasize that a high power factor (PF) is equivalently important for high power generation, in addition to high efficiency. A new n-type Mg 2 Sn-based material, Mg 2 Sn 0.75 Ge 0.25 , is a good example to meet the dual requirements in efficiency and output power. It was found that Mg 2 Sn 0.75 Ge 0.25 has an average ZT of 0.9 and PF of 52 μW·cm ·K−2 over the temperature range of 25-450°C, a peak ZT of 1.4 at 450°C, and peak PF of 55 μW·cm·K −2 at 350°C. By using the energy balance of one-dimensional heat flow equation, leg efficiency and output power were calculated with T h = 400°C and T c = 50°C to be of 10.5% and 6.6 W·cm −2 under a temperature gradient of, respectively.thermoelectrics | magnesium | tin | power factor | output power T hermoelectric power generation from waste heat is attracting more and more attention. Potential fuel efficiency enhancement by recovering the waste heat is beneficial for automobiles and many other applications (1, 2). In addition, solar thermoelectric generator provides an alternative route to convert solar energy into electrical power besides the photovoltaic conversion (3). Thermoelectric generator (TEG) can be regarded as a heat engine using electrons/holes as the energy carrier. The conversion efficiency of a TEG is related to the Carnot efficiency and the material's average thermoelectric figure of merit ZT (4):where ZT = (S 2 σ/κ)T, and S, σ, κ, and T are Seebeck coefficient, electrical conductivity, thermal conductivity, and absolute temperature, respectively. Pursuing high ZT has been the focus of the entire thermoelectric community by applying various phonon engineering via nanostructuring approaches to reduce the thermal conductivity (5-7), or by exploring new compounds with intrinsically low thermal conductivity, such as compounds having complex crystalline structure, local rattlers, liquid-like sublattice, and highly distorted lattice (8-11). However, for practical applications, efficiency is not the only concern, and high output power density is as important as efficiency when the capacity of the heat source is huge (such as solar heat), or the cost of the heat source is not a big factor (such as waste heat from automobiles, steel industry, etc.). The output power density ω is defined as the output power W divided by the cross-sectional area A of the leg, i.e., ω = W/A, which is related to power factor PF = S 2 σ by the following:Eq. 2 contains two main parts: square of the temperature difference divided by leg length, and material power factor PF = S 2 σ.Clearly, to achieve higher power density for a given heat source, we have to either increase the power factor PF or decrease the leg length. However, decreasing the leg length could cause severe consequences such as increase of large heat flux that will incr...

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Section: ·Kmentioning

confidence: 99%

Section: ·Kmentioning

confidence: 99%

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n-type thermoelectric material Mg ₂ Sn _0.75 Ge _0.25 for high power generation

Liu

Kim

Chen

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

198

131

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“…So far, the effect of Agdoping on the thermoelectric properties of Mg 2 Sn have been studied by several groups as it effectively enhances the carrier concentration compared to undoped Mg 2 Sn. 11,12 Despite Cu belonging to the same column of the periodic table (IB) as Ag, and thus could also promote a p-type electrical conductivity, this element has been the subject of fewer studies. Choi et al 11 studied the doping influence of Cu on the carrier concentration of single-phase Mg 2 Sn, while keeping the Mg-to-Sn atomic ratio at about 67: 33.…”

Section: Introductionmentioning

confidence: 99%

“…11,12 Despite Cu belonging to the same column of the periodic table (IB) as Ag, and thus could also promote a p-type electrical conductivity, this element has been the subject of fewer studies. Choi et al 11 studied the doping influence of Cu on the carrier concentration of single-phase Mg 2 Sn, while keeping the Mg-to-Sn atomic ratio at about 67: 33. They reported that doping with only 1% mol Cu did not enhance the carrier concentration in bulk Mg 2 Sn.…”

Section: Introductionmentioning

confidence: 99%

Impacts of Cu-Doping and Mg-Deficiency on Mg2Sn Thin Films Thermoelectric Properties

Safavi

Martin

Aubry

et al. 2021

Journal of Elec Materi

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Two groups of Mg-Sn thin films were deposited by magnetron co-sputtering of Mg, Sn, and Cu targets. Group I was Mg-Sn films with [Mg]/[Sn] = 2 and group II with [Mg]/[Sn] = 1.75. The effect of Mg-deficiency and Cu-doping on the structure and thermoelectric properties was investigated. Both groups were doped by different Cu concentrations (0 at.%, 0.5 at.%, and 1.5 at.%). The structure and morphology of the thin films were investigated. The stable face-centered cubic structure was only observed for undoped film of group I, while a mixture of facecentered cubic and metastable orthorhombic structures coexisted for other samples whatever the Cu content. Carrier concentration and mobility were measured to explain the electronic transport behaviors of the films. The bandgap energy for both groups was estimated by the Kubelka-Munk's method. The influence of the Mg deficiency and Cu doping on the thermoelectric properties was discussed for a range of temperatures: 30-200°C. For both groups, the best figure-of-merit, ZT, was obtained at 200°C for samples doped with 0.5 at.% Cu with ZT = 0.07 for group I and ZT = 0.27 for group II.

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