Synthesis and Functionalization of 1D, 2D Germanium-based Nanostructures

• Author / Creator

  Yu, Haoyang

• The synthesis of germanium nanomaterials with well-defined surface chemistry is of considerable interest, not only because of general scientific curiosity but also because of their vast potential applications in optoelectronics, energy storage, and the semiconductor industry. Covalently bonded organic monolayers play important roles in defining the solution processability, ambient stability, and electronic properties of two-dimensional (2D) materials, such as germanium nanosheets (GeNSs).

  In Chapter 2, we report a straightforward preparative route that yields hydride-terminated germanium nanosheet (H-GeNS) monolayers via sonochemical exfoliation of hydride-terminated germanane flakes (HGe-flakes) derived from crystalline CaGe2. We subsequently show in Chapter 3 that these freestanding H-GeNSs are functionalized readily by a radical-initiated and thermal-induced hydrogermylation reaction. Furthermore, we demonstrate that, upon functionalization, the crystal structure of the GeNSs remains intact, and the introduction of organic moieties to the GeNS surfaces imparts improved thermal stability and solvent compatibility.
  In Chapter 4, we extend the scope of surface linkages to Si—Ge bonding and present the first demonstration of heteronuclear dehydrocoupling of organosilanes to hydride-terminated GeNSs by deintercalation and exfoliation of CaGe2. We further exploit this new surface reactivity and demonstrate the preparation of directly bonded silicon quantum dot-Ge nanosheet hybrids.
  Polygermanes, which contain Ge—Ge backbones are soluble semiconductors with applications in different fields. In Chapter 5, we prepare a stable form of polydihydrogermane with –(GeH2)– repeating units, rigorously characterize its structure, chemical environment, absorption features, and thermal stability, and compare it with unstable polydihydrogermane prepared by a traditional method. We also show that these materials can be applied as a template for ligand substitution via a hydrogermylation reaction (e.g. using 1-dodecene). This facile one-step reaction using Ge–H as the synthetic handle can be utilized to synthesize a variety of functional polygermanes.

• Subjects / Keywords

  • Chemistry
  • Germanium
  • Nanotechnology
  • Surface Functionalization
  • Material Science

• Graduation date

  Fall 2020

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/r3-v0jy-b651

• License

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