Solution preparation of Ge nanoparticles with chemically tailored surfaces

Taylor, Boyd; Fox, Glenn A.; Hope-Weeks, Lousia J; Maxwell, Robert S.; Kauzlarich, Susan M.; Lee, Howard W. H.

doi:10.1016/s0921-5107(02)00297-0

Cited by 34 publications

(27 citation statements)

References 17 publications

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“…Methyl-terminated Ge nanocrystals with an average particle size of around 3.5 nm were produced by the metathesis reaction between the Zintl salt NaGe and GeCl 4 in degassed monoglyme or diglyme. 332 The Kauzlarich and Taylor group 333, 334 further extended this method to prepare alkyl-terminated crystalline Ge nanoparticles by the reactions between GeCl 4 and NaGe, KGe, or Mg 2 Ge followed by surface termination with alkyl Li and Grignard reagents in glymes. It was observed that diglyme and triglyme seemed to support the reaction better than monoglyme and the reactions in triglyme were much faster than in diglyme.…”

Section: Methodsmentioning

confidence: 99%

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

2014

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Glymes, also known as glycol diethers, are saturated non-cyclic polyethers containing no other functional groups. Most glymes are usually less volatile and less toxic than common laboratory organic solvents; in this context, they are more environmentally benign solvents. However, it is also important to point out that some glymes could cause long-term reproductive and developmental damages despite their low acute toxicities. Glymes have both hydrophilic and hydrophobic characters that common organic solvents are lack of. In addition, they are usually thermally and chemically stable, and can even form complexes with ions. Therefore, glymes are found in a broad range of laboratory applications including organic synthesis, electrochemistry, biocatalysis, materials, and Chemical Vapor Deposition (CVD), etc. In addition, glyme are used in numerous industrial applications, such as cleaning products, inks, adhesives and coatings, batteries and electronics, absorption refrigeration and heat pumps, as well as pharmaceutical formulations, etc. However, there is a lack of comprehensive and critical review on this attractive subject. This review aims to accomplish this task by providing an in-depth understanding of glymes’ physicochemical properties, toxicity and major applications.

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Section: Methodsmentioning

confidence: 99%

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

2014

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“…18,19 For over 20 years various physical and chemical routes of the synthesis of Ge qdots have been reported. 15,20,21,17,[22][23][24][25][26][27][28][29] A novel and signicant method of colloidal synthesis, particularly reducing the halides (GeI 2 /GeI 4 ), was recently reported as the most elegant method in terms of size/shape modication and the stability of Ge qdots. [28][29][30] However, this method requires the high temperature Schlenk technique which makes it rather elaborate.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and structure of free-standing germanium quantum dots and their application in live cell imaging

et al. 2015

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“…Passivation techniques developed so far for Ge nanostructures such as thin films, wafers, and wires can be broadly classified into two kinds of techniques. The first are methods that terminate the surface with a Ge–M covalent bond, where M can be hydrogen, a halogen (Cl, Br, I), or an alkyl group, − and the second involves a core–shell approach that passivates the surface by forming a shell around the Ge core. − Surface modification inside a metalattice is more challenging in comparison to wires, films and nanocrystals due to the interconnected structure, high curvature, and high surface area to volume ratio. This added complexity makes it difficult to extend covalent passivation methods to metalattices.…”

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confidence: 99%

Oxide-Free Three-Dimensional Germanium/Silicon Core–Shell Metalattice Made by High-Pressure Confined Chemical Vapor Deposition

et al. 2020

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Metalattices are crystalline arrays of uniform particles in which the period of the crystal is close to some characteristic physical length scale of the material. Here, we explore the synthesis and properties of a germanium metalattice in which the ∼70 nm periodicity of a silica colloidal crystal template is close to the ∼24 nm Bohr exciton radius of the nanocrystalline Ge replica. The problem of Ge surface oxidation can be significant when exploring quantum confinement effects or designing electronically coupled nanostructures because of the high surface area to volume ratio at the nanoscale. To eliminate surface oxidation, we developed a core−shell synthesis in which the Ge metalattice is protected by an oxide-free Si interfacial layer, and we explore its properties by transmission electron microscopy (TEM), Raman spectroscopy, and electron energy loss spectroscopy (EELS). The interstices of a colloidal crystal film grown from 69 nm diameter spherical silica particles were filled with polycrystalline Ge by high-pressure confined chemical vapor deposition (HPcCVD) from GeH 4 . After the SiO 2 template was etched away with aqueous HF, the Ge replica was uniformly coated with an amorphous Si shell by HPcCVD as confirmed by TEM-EDS (energy-dispersive X-ray spectroscopy) and Raman spectroscopy. Formation of the shell prevents oxidation of the Ge core within the detection limit of XPS. The electronic properties of the core−shell structure were studied by accessing the Ge 3d edge onset using STEM-EELS. A blue shift in the edge onset with decreasing size of Ge sites in the metalattices suggests quantum confinement of the Ge core. The degree of quantum confinement of the Ge core depends on the void sizes in the template, which is tunable by using silica particles of varying size. The edge onset also shows a shift to higher energy near the shell in comparison with the Ge core. This shift along with the observation of Ge−Si vibrational modes in the Raman spectrum indicate interdiffusion of Ge and Si. Both the size of the voids in the template and core−shell interdiffusion of Si and Ge can in principle be tuned to modify the electronic properties of the Ge metalattice.

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Solution preparation of Ge nanoparticles with chemically tailored surfaces

Cited by 34 publications

References 17 publications

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

Glymes as versatile solvents for chemical reactions and processes: from the laboratory to industry

Synthesis and structure of free-standing germanium quantum dots and their application in live cell imaging

Oxide-Free Three-Dimensional Germanium/Silicon Core–Shell Metalattice Made by High-Pressure Confined Chemical Vapor Deposition

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