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Kawasaki, Shinji; Kikuchi, Chika; Okino, Fujio; Touhara, Hidekazu

doi:10.1023/a:1006779126522

Cited by 6 publications

(2 citation statements)

References 7 publications

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“…Binary silica–germania glasses exhibit low optical dispersion and the potential for second-harmonic generation . SiO 2 –GeO 2 glass is commonly prepared by melt quench requiring high-temperature processing of viscous molten liquids or layered structures by chemical vapor deposition, limiting glass formation and application. − Sol–gel formation of silica–germania glasses and thin films has been previously reported by cohydrolyzing germanium and silicon alkoxide precursors under acidic conditions. − However, this approach is typically limited to casting-type applications as sols rapidly undergo gelation to form an extended oxide network, instead of stable colloidal sols. Furthermore, with cohydrolysis of Ge- and Si-alkoxide mixtures, the control of compositional speciation is limited …”

Section: Introductionmentioning

confidence: 99%

Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors

et al. 2022

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Core–shell colloids make attractive feedstocks for three-dimensional (3D) printing mixed oxide glass materials because they enable synthetic control of precursor dimensions and compositions, improving glass fabrication precision. Toward that end, we report the design and use of core–shell germania–silica (GeO 2 –SiO 2 ) colloids and their use as precursors to fabricate GeO 2 –SiO 2 glass monoliths by direct ink write (DIW) 3D printing. By this method, GeO 2 colloids were prepared in solution using sol–gel chemistry and formed oblong, raspberry-like agglomerates with ∼15 nm diameter primary particles that were predominantly amorphous but contained polycrystalline domains. An ∼15 nm encapsulating SiO 2 shell layer was formed directly on the GeO 2 core agglomerates to form core–shell GeO 2 –SiO 2 colloids. For glass 3D printing, GeO 2 –SiO 2 colloidal sols were formulated into a viscous ink by solvent exchange, printed into monoliths by DIW additive manufacturing, and sintered to transparent glasses. Characterization of the glass components demonstrates that the core–shell GeO 2 –SiO 2 presents a feasible route to prepare quality, optically transparent low wt % GeO 2 –SiO 2 glasses by DIW printing. Additionally, the results offer a novel, hybrid colloid approach to fabricating 3D-printed Ge-doped silica glass.

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Section: Introductionmentioning

confidence: 99%

Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors

et al. 2022

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“…Hence, the sol-gel technique has been employed to synthesize germanosilicate thin films. Alkoxides such as tetraethyl orthogermanate (TEOG) and tetraethylorthosilicate (TEOS) were selected as precursors for germania and silica, respectively [17][18][19][20][21][22][23]. Junji Niahii et al prepared a 4.6 µm-thick germanosilicate film containing up to 50 mol % germanium oxide by the sputtering deposition method.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of sol–gel 70GeO₂–30SiO₂thick films from TEOG and DEOS and investigation of the 5 eV band

Chen¹,

Hou²,

Zhang³

2006

J. Phys. D: Appl. Phys.

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Crack-free germanosilicate films, 3.6 µm-thick and containing up to 70 mol% germanium dioxide, which are inaccessible through the conventional sol–gel process, were fabricated using tetraethyl orthogermanate (TEOG) and diethylorthosilicate (DEOS) as precursors for germania and silica, respectively. The studies using viscosity, TEM and SEM revealed that DEOS contributed largely to stabilizing the GeO2–SiO2 sol and suppressing crack formation in thick films. XRD study showed that the films remained amorphous after being sintered at 600 °C in air for 60 min and annealed at 550 °C under a flowing H2/N2 atmosphere for 120 min. An intense absorption band at around 241 nm was distinctly observed in the films. The intensity of this absorption band was found to be effectively bleached by UV illumination. Weak photoluminescence emission bands which originated from the neutral oxygen di-vacancy were detected near 375 and 275 nm. Therefore, the 5 eV absorption band observed in this work was mainly caused by the neutral oxygen monovacancy. A saturated absorptivity change of the UV-bleachable band after prolonged illumination was found to be 389 cm−1 for 70GeO2–30SiO2 films.

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Facile liquid phase deposition of thick reflective GeO2 film for hollow waveguide delivery of CO2 laser radiation

Chen

Hou

et al. 2007

Appl. Phys. A

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Untitled

Cited by 6 publications

References 7 publications

Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors

Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors

Fabrication of sol–gel 70GeO₂–30SiO₂thick films from TEOG and DEOS and investigation of the 5 eV band

Facile liquid phase deposition of thick reflective GeO2 film for hollow waveguide delivery of CO2 laser radiation

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Untitled

Cited by 6 publications

References 7 publications

Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors

Silica-Encapsulated Germania Colloids as 3D-Printable Glass Precursors

Fabrication of sol–gel 70GeO2–30SiO2thick films from TEOG and DEOS and investigation of the 5 eV band

Facile liquid phase deposition of thick reflective GeO2 film for hollow waveguide delivery of CO2 laser radiation

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Fabrication of sol–gel 70GeO₂–30SiO₂thick films from TEOG and DEOS and investigation of the 5 eV band