Preparation of Monodisperse GeO₂ Nanocubes in a Reverse Micelle System

Abstract

We report here a synthesis method for single-crystal monodisperse GeO2 nanocubes in a reverse micelle system. Hydrolysis of germanium tetrachloride (GeCl4) in a micelle system produces GeO2 nanocubes in the presence of oleylamine and cetyltrimethylammonium (CTAB). The average edge length of the cubes varies from 50 to 520 nm depending on the concentration of CTAB in the solution. The perfection and monodispersity of the nanocubes are greatly improved by decreasing the pH value of the water solution. Different morphologies such as capsules can be prepared by using octane as the oil phase. The BFDH and Hartman-Perdok methods were used to predict the morphology evolution during the growth of GeO2 nanocubes.

Extreme biomimetic approach for developing novel chitin-GeO2 nanocomposites with photoluminescent properties

“…Therefore, it is important to develop synthesis methods that will allow control over the morphology and crystallinity of GeO 2 . Thus far, several different technologies have been developed for the synthesis of germanium oxide with these desired properties, including sol-gel reactions [18,[27][28][29], thermal evaporation [30], the reverse micelle method [31], direct precipitation followed by calcination [32,33], as well as thermal oxidation [34,35]. Template-directed approaches including hard templates using carbon nanotubes [36] or soft-templates with surfactants [37], 2-methyl pentamethylene diamine [38], and ionic liquids [39], have been investigated for their ability to synthesize specific crystalline phases of germanium oxide.…”

Morphology controls of GeO2 particles precipitated by a facile acid-induced decomposition of germanate ions in aqueous medium

“…GeO 2 is a dielectric oxide and a blue photoluminescence material with peak energies around 2.2 and 3.1 eV, and it has a refractive index and a linear coefficient of thermal expansion that are higher than those for SiO 2 [9][10][11]. Moreover, it is a promising material for optical waveguides and nano-connections in optoelectronic communication and vacuum technology [12][13][14][15][16]. Due to these fascinating properties, great attention has been paid to the preparation of GeO 2 nano-structures, including nano-particles, nanofibers and nano-sheets [6][7][8][9][10][11][12][13][14][15][16].…”

“…Germanium alkoxides or halides are the precursors generally used to synthesize GeO 2 materials through wet chemical process [12,[14][15][16][17][18][19][20]. Because these precursors are pretty moisturesensitive, the reversed micelles have often been used to obtain monodisperse GeO 2 particles [15,16].…”

Synthesis and characterization of nano/micro-structured crystalline germanium dioxide with novel morphology

“…During the early stage of the reaction, the H 3 GeO 6 − phase was obtained, which is a precursor of GeO 2 [8] . Therefore, we propose that the reactions relevant to the formation of the nano/micro-structured GeO 2 are as follows: (3) In these reactions, the water produced from Reaction (1) is in the form of liquid droplets in the system, as water does not dissolve in CHCl 3 .…”

“…GeO 2 nanoparticles have been prepared by DC-magnetron sputtering and heat annealing [7] . Monodispersive GeO 2 nanocubes have been synthesized in a reverse micelle system [8,9] . GeO 2 nanosheets have been produced by hydrolysis and condensation reactions of germanium alkoxide using the liquid-liquid interface of water/surfactant as a confined reaction field [10] .…”