Solution Synthesis and Characterization of Quantum Confined Ge Nanoparticles

Abstract

A solution synthesis of crystalline Ge nanoparticles (nc-Ge ) is reported. The metathesis reaction of NaGe with excess GeCl 4 in glyme solvents produces nc-Ge. Metathesis reactions between KGe and excess GeCl 4 or GeCl 2 :(dioxane) in glyme and Mg 2 Ge and excess GeCl 4 in diglyme and triglyme were also investigated. The surface of these nanoparticles is terminated with alkyl groups by reaction with alkyl Li and Grignard reagents. The alkyl-terminated crystalline Ge nanoparticles (R ˆ-nc-Ge) were characterized by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, powder X-ray diffraction, UV-vis absorption spectroscopy, photoluminescence, and photoluminescence excitation spectroscopy. The optical properties of R ˆ-nc-Ge made by this method agree with predictions from quantum confinement models.

Germanium nanocrystals as luminescent probes for rapid, sensitive and label-free detection of Fe3+ions

“…26 All sensing applications rely on the ability to prepare luminescent NCs with high quantum yields and well characterised surface chemistries, as these factors define many of their photophysical properties and response to analytes. A number of different solution phase approaches for synthesis of functionalised, luminescent Ge NCs have been reported, including the metathesis reaction of GeCl 4 with Zintl salts 27,28 and high temperature decomposition of organogermane precursors. 29,30 Other methods include thermal co-reduction of amido based precursors, 31 aqueous phase reduction of GeO 2 powders by NaBH 4 , 32 reduction of germanium halides [33][34][35][36][37] and other high temperature chemical reduction methods.…”

Synthesis of Nanoamorphous Germanium and Its Transformation to Nanocrystalline Germanium

“…Bottom-up solution-phase synthetic chemistry methods offer better control of the size and shape of the nanoparticles, but often do not provide the good crystallinity required for many applications, and require the use of longchain ligands and surfactants to stabilize the particle surface and control growth. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] Due to their ease of preparation, these solution-phase methods are also more accessible to many researchers and more amenable to scaling. As a result, their development is in great demand to prepare high-quality materials for detailed chemistry and physical studies, essential for their eventual integration into practical devices.…”

“…[8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] The germanium sources in these investigations are usually the germanium halides, GeX n , or organogermanes [23,24] in which the Ge center is either in the 4 + or 2 + oxidation state (e.g., GeCl 4 , GeBr 4 , GeI 2 ), and long-chain phosphines and alkenes are often used as surface protection ligands for nanoparticle stabilization. The reducing agents used in these investigations are usually the strong ones, such as LiAlH 4 , NaBH 4 , sodium, sodium naphthalide, butyllithium, and Ge Zintl salts.…”

“…The reducing agents used in these investigations are usually the strong ones, such as LiAlH 4 , NaBH 4 , sodium, sodium naphthalide, butyllithium, and Ge Zintl salts. [12][13][14][15][16][17][18][19][20][21][22][23][24] In these reactions, the strength of the reducing agent and the reduction reaction rate are related to each other, and usually these strong reducing agents react very quickly such that the reaction kinetics and nanocrystal growth rates cannot be explored and are not under fine control. Slowing these reduction steps and collecting kinetic information will be very beneficial for the synthesis of Ge nanoparticles and will gainfully contribute to the nanochemistry of these systems.…”

Photoluminescence of Ultraviolet Initiated Green Emission from Electrochemically Deposited Germanium Films on (100) Silicon

“…There are cost-effective chemical-solution techniques available for the preparation of freestanding colloid z E-mail: vijay.arora@wilkes.edu nanocrystals. 16 Electrochemical deposition of Ge on Si is an inexpensive and fast synthesis method to produce good quality semiconductor thin films and nanostructures 17 for exploration with PL.…”