Bright visible photoluminescence from silica nanotube flakes prepared by the sol–gel template method

Abstract

We report macroscopic synthesis of silica nanotubes by the sol–gel template method. A large number of silica nanotubes with small diameters (30–50 nm) were produced and were shaped into flakes successfully. Strong photoluminescence (PL) was observed in both as-grown and annealed nanotube flakes. The PL spectra have maxima at 2.55 and 2.30 eV for the as-grown and annealed samples, respectively; the PL intensity of annealed nanotubes is much higher than that of as-grown nanotubes. The strong emission may be due to the Si–OH complex located on both the inner and outer surfaces of the nanotubes. The nanotube flakes we prepared may have potential applications in future integrated optical devices.

Synthesis and Cathodoluminescence of Morphology-Tunable SiO2 Nanotubes and ZnS/SiO2 Core−Shell Structures Using CdSe Nanocrystals as the Seeds

“…These results are in agreement with those reported previously. [52][53] No obvious Si peaks (Si2p at 98.7 eV in Si) are observed. All XRD, EDS, and XPS analyses indicate that the as-prepared products are amorphous SiO 2 .…”

“…The strong blue emission at 460 nm is similar to the result for the amorphous silica nanowires synthesized using the laser ablation approach. 57 However, it was different from the emission bands of silica nanotubes prepared by the sol-gel template method (SGTM) 29,53 Zhang et al 53 observed the emissions centered at 486 nm, and Jang et al 29 found the emissions centered at 435 nm with shoulders at 410 and 460 nm. Compared with the emissions previously reported, the intensive peak at 435 nm in ref 29 disappears in Figure 10 while the shoulder at 460 nm changes into the intensive peak.…”

Thermal quenching properties of ultraviolet emitting centers in mesoporous silica

“…[1][2][3][4][5][6] As regards silica-based nanostructered materials, red, green, and blue emissions from silica nanoparticles, mesoporous silica, and silica nanotubes were reported with strong similarities with the spectroscopic features observed in nanoscaled silicon. [7][8][9][10] Since the thickness of the bulk silica walls in nanostructured silica materials ͓ϳ1 nm ͑Ref. 11͔͒ is comparable to the thickness of oxide layers which cover silicon in nanoscaled silicon materials, these similarities can help to clarify the debated origin of the observed features.…”

Structural and Dynamic Properties of (SiO2)6 Silica Nanostructures: A Quantum Molecular Dynamics Study

“…Earlier, Harkless and co-workers 5 employed classical molecular dynamic simulations to search for stable/metastable nanostructures of SiO 2 clusters, but what they found was soon shown to be quite different from ab initio and density functional theory (DFT) results. 9 Flikkema and Bromley 8 later improved the interatomic potential and confirmed a few building blocks for nanoscale silica.…”

“…[2][3][4] While extensive studies from both experimental and theoretical perspectives have been available, [5][6][7][8][9][10] many questions about their structural and dynamic properties still remain unanswered. For example, how are silica nanowires formed?…”