Intercalation: Building a Natural Superlattice for Better Thermoelectric Performance in Layered Chalcogenides
Intercalation: Building a Natural Superlattice for Better Thermoelectric Performance in Layered Chalcogenides
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DOI：
10.1007/s11664-011-1565-5
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发表时间：
2011-03
影响因子：
2.1
通讯作者：
C. Wan;Yifeng Wang;Ning Wang;W. Norimatsu;M. Kusunoki;K. Koumoto
中科院分区：
文献类型：
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作者：
C. Wan;Yifeng Wang;Ning Wang;W. Norimatsu;M. Kusunoki;K. Koumoto
利用高分辨透射电子显微镜（HRTEM）直接观察到了一种天然超晶格，其组成为（SnS）1.2（TiS 2）2，是通过在TiS 2的货车范德华能隙中插入SnS层而形成的。热电性能在平行于层的方向上得到改善，因为在保持电子迁移率的同时抑制声子输运，这归因于由于层间结合减弱而导致的横向声速软化。在垂直于层的方向上，（SnS）1.2（TiS 2）2的晶格热导率甚至低于预测的最小热导率，这可能是由于平行于层的SnS层的平移无序引起的声子局域化引起的.此外，我们提出了一个大家族的失配层化合物（MX）1+x（TX 2）n（M = Pb，Bi，Sn，Sb，稀土元素; T = Ti，V，Cr，Nb，Ta; X = S，Se;n= 1，2，3）作为可能的候选高性能热电材料的天然超晶格结构。
A natural superlattice with composition (SnS)1.2(TiS2)2, built by intercalating a SnS layer into the van der Waals gap of layered TiS2, has been directly observed by high-resolution transmission electron microscopy (HRTEM). The thermoelectric performance is improved in the direction parallel to the layers because the electron mobility is maintained while simultaneously suppressing phonon transport, which is attributed to softening of the transverse sound velocities due to weakened interlayer bonding. In the direction perpendicular to the layers, the lattice thermal conductivity of (SnS)1.2(TiS2)2is even lower than the predicted minimum thermal conductivity, which may be caused by phonon localization due to the translational disorder of the SnS layers parallel to the layers. Moreover, we propose a large family of misfit-layer compounds (MX)1+x(TX2)n(M = Pb, Bi, Sn, Sb, rare-earth elements; T = Ti, V, Cr, Nb, Ta; X = S, Se;n= 1, 2, 3) with a natural superlattice structure as possible candidate high-performance thermoelectric materials.