Low-Temperature Hydrothermal Synthesis of Amorphous SiO[sub 2] Nanoblades Without Using Template and Their Intense Blue Photoluminescence

Abstract

One-dimensional (1D) amorphous SiO2SiO2 nanoblades were synthesized by a low-temperature hydrothermal process in an aqueous solution without using template. The presence of NaOH and urea is crucial for the formation of anisotropic SiO2SiO2 nanostructures, but their concentrations should be carefully controlled to obtain large-scale SiO2SiO2 nanoblades. Increasing the synthesis temperature will increase the aspect ratios of the resultant SiO2SiO2 nanoblades. Intense blue luminescence centered at 3.0 and 2.8eV2.8eV was observed in the as-synthesized SiO2SiO2 nanoblades, and the photoluminescence (PL) peak intensities were reduced by ∼21%∼21% and 44% after oxygen annealing at 300 and 600°C600°C , respectively. The zero-crossing gg value in the electron paramagnetic resonance spectra was calculated to be 2.0000, implying that there exists many E′E′ defect centers in the as-synthesized SiO2SiO2 nanoblades. The 2.8-eV2.8-eV band can be attributed to the neutral oxygen-vacancy defects, while the 3.0-eV3.0-eV band may be due to the H-complexed oxygen vacancies. (c) The Electrochemical Society.