Intrinsic Low Thermal Conductivity and Phonon Renormalization Due to Strong Anharmonicity of Single-Crystal Tin Selenide

Nano Letters ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 4941-4948 ◽  
Author(s):  
Joon Sang Kang ◽  
Huan Wu ◽  
Man Li ◽  
Yongjie Hu
2000 ◽  
Vol 626 ◽  
Author(s):  
Antje Mrotzek ◽  
Kyoung-Shin Choi ◽  
Duck-Young Chung ◽  
Melissa A. Lane ◽  
John R. Ireland ◽  
...  

ABSTRACTWe present the structure and thermoelectric properties of the new quaternary selenides K1+xM4–2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22. The compounds K1+xM4-2xBi7+xSe15 (M= Sn, Pb) crystallize isostructural to A1+xPb4-2xSb7+xSe15 with A = K, Rb, while K1-xSn5-xBi11+xSe22 reveals a new structure type. In both structure types fragments of the Bi2Te3-type and the NaCl-type are connected to a three-dimensional anionic framework with K+ ions filled tunnels. The two structures vary by the size of the NaCl-type rods and are closely related to β-K2Bi8Se13 and K2.5Bi8.5Se14. The thermoelectric properties of K1+xM4-2xBi7+xSe15 (M = Sn, Pb) and K1-xSn5-xBi11+xSe22 were explored on single crystal and ingot samples. These compounds are narrow gap semiconductors and show n-type behavior with moderate Seebeck coefficients. They have very low thermal conductivity due to an extensive disorder of the metal atoms and possible “rattling” K+ ions.


Author(s):  
Chongjian Zhou ◽  
Yong Kyu Lee ◽  
Yuan Yu ◽  
Sejin Byun ◽  
Zhong-Zhen Luo ◽  
...  

AbstractThermoelectric 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.


2018 ◽  
Vol 6 (37) ◽  
pp. 10083-10087 ◽  
Author(s):  
Giuk Jeong ◽  
Yoon Hwan Jaung ◽  
Jekyung Kim ◽  
Jae Yong Song ◽  
Byungha Shin

Tin selenide (Sn1−xSe) polycrystalline thin films were prepared by thermal co-evaporation, and the thermoelectric properties of the Sn1−xSe thin films were investigated.


2020 ◽  
Author(s):  
Akira Nagaoka ◽  
Kenji Yoshino ◽  
Taizo Masuda ◽  
Taylor Sparks ◽  
Michael Scarpulla ◽  
...  

Abstract Thermoelectrics (TEs) are an important class of technologies for harvesting electric power directly from heat sources. To design high performace TE materials, valleytronics has great theoretical potential to maximize a dimensionless figure of merit ZT but has not yet been demonstrated experimentally. Pseudocubic structure approach based on valleytronics paves a new path to manipulate valley degeneracy and anisotoropy with low thermal conductivity caused by short-range lattice distortion. Here, we report a record high ZT = 1.6 around 800 K, realized in totally enviromentally benign Na-doped Cu2ZnSnS4 (CZTS) single crystal. The exceptional performance comes from a high power factor while maintaining intrinsically low thermal conductivity. The results demonstrate that valleytronics is a new strategy and direction in the TE field, which takes advantage of simple material nature tuning without complex techniques.


2017 ◽  
Vol 5 (5) ◽  
pp. 1255-1260 ◽  
Author(s):  
Tao Ye ◽  
Xizu Wang ◽  
Xianqiang Li ◽  
Alex Qingyu Yan ◽  
Seeram Ramakrishna ◽  
...  

A centimeter-sized organic–inorganic hybrid lead-based perovskite CH3NH3PbI3(MAPbI3) single crystal was obtained by using a modified fast and inverse-temperature growth method.


RSC Advances ◽  
2017 ◽  
Vol 7 (48) ◽  
pp. 29959-29965 ◽  
Author(s):  
Huicong Dong ◽  
Bin Wen ◽  
Yuwen Zhang ◽  
Roderick Melnik

Low thermal conductivity of Si/Ge hetero-twinned superlattice, in comparison with that of single crystal Si, twinned Si, Si/Ge alloy and conventional Si/Ge superlattice.


Author(s):  
Wenxin Wei ◽  
Guifeng Ma ◽  
Hongtao Wang ◽  
Jun Li

Objective: A new poly(ionic liquid)(PIL), poly(p-vinylbenzyltriphenylphosphine hexafluorophosphate) (P[VBTPP][PF6]), was synthesized by quaternization, anion exchange reaction, and free radical polymerization. Then a series of the PIL were synthesized at different conditions. Methods: The specific heat capacity, glass-transition temperature and melting temperature of the synthesized PILs were measured by differential scanning calorimeter. The thermal conductivities of the PILs were measured by the laser flash analysis method. Results: Results showed that, under optimized synthesis conditions, P[VBTPP][PF6] as the thermal insulator had a high glass-transition temperature of 210.1°C, high melting point of 421.6°C, and a low thermal conductivity of 0.0920 W m-1 K-1 at 40.0°C (it was 0.105 W m-1 K-1 even at 180.0°C). The foamed sample exhibited much low thermal conductivity λ=0.0340 W m-1 K-1 at room temperature, which was comparable to a commercial polyurethane thermal insulating material although the latter had a much lower density. Conclusion: In addition, mixing the P[VBTPP][PF6] sample into polypropylene could obviously increase the Oxygen Index, revealing its efficient flame resistance. Therefore, P[VBTPP][PF6] is a potential thermal insulating material.


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