Enhanced Thermoelectric Performance and Mechanical Property in Layered Chalcostibite CuSb_1–xPb_xSe₂

Abstract

In this work, the thermoelectric properties of p-type layered chalcostibite CuSb 1−x Pb x Se 2 (x = 0−0.10) compounds prepared by vacuum melting reaction and uniaxial hot press, have been studied in the temperature range of 323−623 K. Further, aliovalent Pb 2+ doping at Sb 3+ site in CuSbSe 2 notably increases the hole concentration due to its acceptor nature and thereby enhances the electrical conductivity, σ. Importantly, a huge reduction in total thermal conductivity, κ total has been noticed, from ∼1.7 W/mK (pristine CuSbSe 2 ) to ∼0.72 W/mK at 323 K for CuSb 0.90 Pb 0.10 Se 2 owing to increased phonon scattering from the introduced point defects and mass-difference between Pb and Sb. As a result, the thermoelectric figure of merit, zT, has been enhanced to ∼0.27 at 623 K for the composition of CuSb 0.90 Pb 0.10 Se 2 , which is 3-fold higher than that of the undoped CuSbSe 2 . Further, the hardness value achieved was ∼125.54 Hv, which is significantly higher than the most of the state-of-the-art materials, indicating it to be an efficient thermoelectric material for intermediate temperature.

Enhancement in Thermoelectric Performance in Ti-doped Yb0.4Co4Sb12 Skutterudites via Carrier Optimization and Phonon Anharmonicity

“…(a) Load vs displacement curves for pristine Co 4 Sb 12 and Yb 0.4 ­Co 3.96 ­Ti 0.04 ­Sb 12 and their corresponding hardness values. (b) Comparative representation of Vickers hardness of pristine Co 4 Sb 12 and Yb 0.4 ­Co 3.96 ­Ti 0.04 ­Sb 12 with previously reported Ge 0.9 ­Sb 0.1 ­Te, Cu­Sb 1– x ­Pb x ­Se 2 ( x = 0–0.10), (Ge 0.9 ­Sb 0.1 ­Te) 0.97 ­(Mg­B 2 ) 0.03 , Cu 1.9 ­Ag 0.1 ­Te 0.6 ­S 0.2 ­Se 0.2 , Cu 2 Se–0.42 wt % B, SnTe–10 vol % SiC, Sn 0.86 ­Bi 0.03 ­Sb 0.14 ­Te, Sn 0.4 ­Ag 0.3 ­Sb 0.3 ­Se 0.4 ­Te 0.6 , and Bi 0.92 ­Pb 0.08 ­Cu­Se­O + 0.10 nano-SiC based materials.…”

“…From the nanoindentation, the hardness of Co 4 Sb 12 is measured as ∼7.97 ± 0.3 GPa, whereas the Yb 0.4 ­Co 3.96 ­Ti 0.04 ­Sb 12 sample has a hardness value of 8.24 ± 0.3 GPa. The reason behind improved hardness is attributed to the interruption of dislocation motion and strong bonding of heavy element Ti at the lattice site Figure b shows the composition plot of the Vickers hardness of the state-of-the-art TE materials along with Yb 0.4 ­Co 4– x ­Ti x ­Sb 12 samples.…”

“…The reason behind improved hardness is attributed to the interruption of dislocation motion and strong bonding of heavy element Ti at the lattice site. 68 Figure 8b shows the composition plot of the Vickers hardness of the state-of-the-art TE materials along with Yb 0.4 Co 4−x Ti x Sb 12 samples. It is observed that the compositions of Co 4 Sb 12 and Yb 0.4 Co 3.96 -Ti 0.04 Sb 12 have hardness of 580.5 H V and 583.64 H V , which are significantly higher than those of traditional high-performance TE materials, such as CuSbSe 2 , 68 GeTe, 57,69 Cu 2 Te, 70 Cu 2 Se, 71 SnTe, 72−74 and BiCuSeO.…”

Sulfur Vacancy-Driven Band Splitting and Phonon Anharmonicity Enhance the Thermoelectric Performance in n-Type CuFeS2

“…), and normal process (τ N −1 ). When only the point defect and Umklapp process are considered, the relationship becomes 55,56,59,60 = +…”

“…To reveal the reason behind the significant reduction in the κ latt , the Debye model was employed to fit κ latt vs T data and examined the various scattering contributions using the following relation − κ latt = 4 π k B 4 T 3 ν h 3 ∫ 0 θ D / T τ T z 4 exp false( z false) false[ exp ( z ) − 1 false] 2 d z where ν , z , θ D , and τ T represent the velocity of sound, reduced phonon frequency, Debye temperature, and phonon relaxation time, respectively. Further, Matthiessen’s rule is used to determine the total phonon relaxation time, τ –1 , by using the relation ,,, τ − 1 = τ PD − 1 + τ normalU − 1 + τ normalB − 1 + τ normalN − 1 + ... which is related to the scattering relaxation time of the point defects (τ PD –1 ), Umklapp process (τ U –1 ), boundary scattering (τ B –1 ), and normal process (τ N –1 ).…”