1. Fabrication of pseudo-crystal nanostructures of TiO2 particles under UV-irradiation
- Author
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Shin Yh, Yun Sh, Kim Km, Kim, Young Keun Kim, Lee Sw, Lim Jh, and Lee Mj
- Subjects
Materials science ,Absorption spectroscopy ,Band gap ,Scanning electron microscope ,Biomedical Engineering ,Nanoparticle ,Bioengineering ,General Chemistry ,Condensed Matter Physics ,medicine.disease_cause ,chemistry.chemical_compound ,Chemical engineering ,chemistry ,Titanium dioxide ,medicine ,Particle ,General Materials Science ,Titanium isopropoxide ,Ultraviolet - Abstract
Colloidal titanium dioxide (TiO2) suspensions were synthesized by hydrolysis of titanium isopropoxide in the presence of acetic acid. When TiO2 colloids were subjected to bandgap excitation (ultraviolet [UV] irradiation), the colloidal solution exhibited yellow coloration, leading to the trapping of holes and electrons on the particle surfaces. The absorption spectra indicated a distinct absorption band in the UV and visible region. Dried-drop film of the UV-irradiated TiO2 suspension on the mica surface was characterized by scanning electron microscopy (SEM). SEM images showed that "crystal-like" network structures of TiO2 nanoparticles had formed dramatically on the solid surface. The resulting networks ranged in size from 100 nm to 500 nm and had crystal-growth patterns, while also having almost similar rectangular shapes. It seems that the individual particles, with electron or hole scavengers such as oxygen in ambient conditions, make contact with a number of neighbors, thereby forming self-assembled three-dimensional nanoparticle-based pseudo-crystalline structures.
- Published
- 2009