Toyota Central R&D Laboratories, Inc., Nagakute, Aichi 480-1192, Japan.
J Am Chem Soc. 2010 Mar 3;132(8):2710-8. doi: 10.1021/ja908827z.
Silicon nanomaterials are encouraging candidates for application to photonic, electronic, or biosensing devices, due to their size-quantization effects. Two-dimensional silicon nanosheets could help to realize a widespread quantum field, because of their nanoscale thickness and microscale area. However, there has been no example of a successful synthesis of two-dimensional silicon nanomaterials with large lateral size and oxygen-free surfaces. Here we report that oxygen-free silicon nanosheets covered with organic groups can be obtained by exfoliation of layered polysilane as a result of reaction with n-decylamine and dissolution in an organic solvent. The amine residues are covalently bound to the Si(111) planes. It is estimated that there is ca. 0.7 mol of residue per mole of Si atoms in the reaction product. The amine-modified layered polysilane can dissolve in chloroform and exfoliate into nanosheets that are 1-2 microm wide in the lateral direction and with thicknesses on the order of nanometers. The nanosheets have very flat and smooth surfaces due to dense coverage of n-decylamine, and they are easily self-assembled in a concentrated state to form a regularly stacked structure. The nanosheets could be useful as building blocks to create various composite materials.
硅纳米材料由于其尺寸量子化效应，是应用于光子学、电子学或生物传感器件的有前途的候选材料。二维硅纳米片由于其纳米级厚度和微尺度面积，有助于实现广泛的量子领域。然而，还没有成功合成具有大横向尺寸和无氧表面的二维硅纳米材料的例子。在这里，我们报告说，通过层状聚硅烷与正癸胺反应并溶解在有机溶剂中，可将覆盖有有机基团的无氧硅纳米片从层状聚硅烷中剥离出来。胺残留物通过共价键与 Si(111) 平面结合。反应产物中，估计每个硅原子有大约 0.7 摩尔的残留物。胺修饰的层状聚硅烷可溶解于氯仿中，并剥离成横向宽度为 1-2 微米、厚度为纳米级的纳米片。由于正癸胺的致密覆盖，纳米片具有非常平坦和光滑的表面，并且它们在浓缩状态下很容易自组装形成规则堆叠的结构。这些纳米片可用作构建各种复合材料的基本材料。
