Casamento Joseph, Lopez Juan S, Moroz Nicholas A, Olvera Alan, Djieutedjeu Honore, Page Alexander, Uher Ctirad, Poudeu Pierre F P
Laboratory for Emerging Energy and Electronic Materials, Department of Materials Science and Engineering, and ‡Department of Physics, University of Michigan , Ann Arbor, Michigan 48109, United States.
Inorg Chem. 2017 Jan 3;56(1):261-268. doi: 10.1021/acs.inorgchem.6b02118. Epub 2016 Dec 19.
PbBiSe, the selenium analogue of heyrovsyite, crystallizes in the orthorhombic space group Cmcm (#63) with a = 4.257(1) Å, b = 14.105(3) Å, and c = 32.412(7) Å at 300 K. Its crystal structure consists of two NaCl-type layers, A and B, with equal thickness, N = N = 7, where N is the number of edge-sharing [Pb/Bi]Se octahedra along the central diagonal. In the crystal structure, adjacent layers are arranged along the c-axis such that bridging bicapped trigonal prisms, PbSe, are located on a pseudomirror plane parallel to (001). Therefore, PbBiSe corresponds to a L member of the lillianite homologous series. Electronic transport measurements indicate that the compound is a heavily doped narrow band gap n-type semiconductor, with electrical conductivity and thermopower values of 350 S/cm and -53 μV/K at 300 K. Interestingly, the compound exhibits a moderately low thermal conductivity, ∼1.1 W/mK, in the whole temperature range, owing to its complex crystal structure, which enables strong phonon scattering at the twin boundaries between adjacent NaCl-type layers A and B. The dimensionless figure of merit, ZT, increases with temperature to 0.25 at 673 K.
PbBiSe是黑螺钒矿的硒类似物，在正交空间群Cmcm（#63）中结晶，300K时a = 4.257(1) Å，b = 14.105(3) Å，c = 32.412(7) Å。其晶体结构由两个厚度相等的NaCl型层A和B组成，N = N = 7，其中N是沿中心对角线共享边的[Pb/Bi]Se八面体的数量。在晶体结构中，相邻层沿c轴排列，使得桥连双帽三棱柱PbSe位于平行于(001)的伪镜面上。因此，PbBiSe属于硫铋铅矿同系物的L成员。电子输运测量表明，该化合物是一种重掺杂窄带隙n型半导体，300K时电导率和热电势值分别为350 S/cm和-53 μV/K。有趣的是，由于其复杂的晶体结构，该化合物在整个温度范围内表现出适度较低的热导率，约为1.1 W/mK，这使得相邻NaCl型层A和B之间的孪晶界处能够发生强烈的声子散射。无量纲品质因数ZT在673K时随温度升高至0.25。
