Chung Duck-Young, Hogan Tim P, Rocci-Lane Melissa, Brazis Paul, Ireland John R, Kannewurf Carl R, Bastea Marina, Uher Ctirad, Kanatzidis Mercouri G
Department of Chemistry and Center for Fundamental Materials Research, Michigan State University, East Lansing, Michigan 48824, USA.
J Am Chem Soc. 2004 May 26;126(20):6414-28. doi: 10.1021/ja039885f.
The highly anisotropic material CsBi(4)Te(6) was prepared by the reaction of Cs/Bi(2)Te(3) around 600 degrees C. The compound crystallizes in the monoclinic space group C2/m with a = 51.9205(8) A, b = 4.4025(1) A, c = 14.5118(3) A, beta = 101.480(1) degrees, V = 3250.75(11) A(3), and Z = 8. The final R values are R(1) = 0.0585 and wR(2) = 0.1127 for all data. The compound has a 2-D structure composed of NaCl-type [Bi(4)Te(6)] anionic layers and Cs(+) ions residing between the layers. The [Bi(4)Te(6)] layers are interconnected by Bi-Bi bonds at a distance of 3.2383(10) A. This material is a narrow gap semiconductor. Optimization studies on the thermoelectric properties with a variety of doping agents show that the electrical properties of CsBi(4)Te(6) can be tuned to yield an optimized thermoelectric material which is promising for low-temperature applications. SbI(3) doping resulted in p-type behavior and a maximum power factor of 51.5 microW/cm.K(2) at 184 K and the corresponding ZT of 0.82 at 225 K. The highest power factor of 59.8 microW/cm.K(2) at 151 K was obtained from 0.06% Sb-doped material. We report here the synthesis, physicochemical properties, doping characteristics, charge-transport properties, and thermal conductivity. Also presented are studies on n-type CsBi(4)Te(6) and comparisons to those of p-type.
通过在600摄氏度左右使铯与碲化铋（Bi₂Te₃）反应制备出了高度各向异性的材料CsBi₄Te₆。该化合物结晶于单斜空间群C2/m，a = 51.9205(8) Å，b = 4.4025(1) Å，c = 14.5118(3) Å，β = 101.480(1)°，V = 3250.75(11) ų，Z = 8。所有数据的最终R值为R(1) = 0.0585，wR(2) = 0.1127。该化合物具有二维结构，由NaCl型的[Bi₄Te₆]阴离子层和位于层间的Cs⁺离子组成。[Bi₄Te₆]层通过距离为3.2383(10) Å的Bi - Bi键相互连接。这种材料是一种窄带隙半导体。使用多种掺杂剂对热电性能进行的优化研究表明，CsBi₄Te₆的电学性能可以通过调整来产生一种优化的热电材料，有望用于低温应用。SbI₃掺杂导致p型行为，在184 K时最大功率因子为51.5 μW/cm·K²，在225 K时相应的ZT为0.82。从0.06% Sb掺杂的材料中在151 K时获得了最高功率因子59.8 μW/cm·K²。我们在此报告其合成、物理化学性质、掺杂特性、电荷传输性质和热导率。还展示了对n型CsBi₄Te₆的研究以及与p型的比较。
