Materials Science Institute and Department of Chemistry, 1253 University of Oregon, Eugene, OR 97403, USA.
Sandia National Laboratories, Energy Nanomaterials Department, Livermore, CA 94551, USA.
Nanoscale. 2016 Jul 14;8(28):13646-51. doi: 10.1039/c6nr03406c.
Targeted heterostructures containing intergrown two dimensional (2D) layers of 3 different constituent layers, SnSe2, PbSe and TiSe2, were prepared by controlling the composition and sequence of elemental bilayers within a designed precursor. Varying the structure of the precursor enabled the number of structural units of each constituent and the sequence of crystalline 2D layers to be precisely controlled. The stacking of the 2D layers, their structures, and the segregation of the elements between them were determined using X-ray diffraction and electron microscopy techniques, with the observed sequence of the 2D layers consistent with the targeted intergrowth. This ability to prepare targeted heterostructures is critical, since the number of possible configurations in the final compound increases rapidly as the number of constituents increases, from almost 60 000 with two constituents to over 130 million with three constituents and to over 35 billion with four constituents for 20 or fewer distinct layers in the unit cell. This general route for synthesizing specific multiple component heterostructures will accelerate the feedback loop in this growing research area, permitting theorists to assume specific structures in the search for enhanced properties and providing experimentalists with crystallographically aligned samples to test these predictions.
目标是通过控制设计前体中元素双层的组成和顺序来制备包含三种不同成分层（SnSe2、PbSe 和 TiSe2）的互生长二维（2D）层的靶向异质结构。通过改变前体的结构，可以精确控制每个成分的结构单元数量和结晶 2D 层的顺序。使用 X 射线衍射和电子显微镜技术确定了 2D 层的堆叠、结构以及它们之间元素的分凝，观察到的 2D 层顺序与目标互生长一致。这种制备靶向异质结构的能力至关重要，因为随着成分数量的增加，最终化合物中的可能配置数量迅速增加，从两个成分时的近 6 万个增加到三个成分时的超过 1.3 亿个，再到四个成分时的超过 350 亿个，而每个单元晶胞中只有 20 个或更少的不同层。这种合成特定多组分异质结构的一般途径将加速这个不断发展的研究领域的反馈循环，允许理论学家在寻找增强性能的过程中假设特定的结构，并为实验学家提供晶体排列的样品来检验这些预测。
