Computational and optoelectronic studies of rare earth metals doped titania for photochromic applications
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Date
2014-11-28
Authors
Osoro, Mosiori Geoffrey
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Nanofabrication of Ti02 makes it useful in varieties of applications like photocatalysis,
photochromic devices, self-cleaning coatings, fog proof glass and water purifier. Titanium
(IV)-oxide occurs in nature in three mineral forms: anatase, brookite and rutile. All three
forms are characterized with high refractive index, low absorption and low dispersion in
visible and near-infrared spectral regions, high chemical and thermal stabilities. This
important metal-oxide semiconductor with relatively wide band gap (3.25 eV for anatase, 3.0
eV for rutile, 1.9 eV for brookite) and low phonon energy «700 em") is an excellent host for
various rare earth (RE) impurities providing their efficient emission in visible range. These
systems are of possible interest in white light emission diode (LED) industry, photocatalysts
and photochromic applications. At the same time, being non-toxic and biocompatible, rareearth
doped anatase has strong potential to replace standard types of fluorophores (quantum
dots, organic dyes, etc.), traditionally used as fluorescent markers in medicine and biological
applications. Titanium and Rare earth doped Ti02 nanoparticles will be synthesized by sol gel
and wet precipitation method. Theoretical optical properties will be estimated by density
functional theory (DFT) using quantum EXPRESSO software, which will be corroborated
with experimental data. Morphological and structural properties will be characterized by
Scanning electron microscope (SEM), transmission electron microscope (TEM) Energy
dispersive X-ray (EDX), X-ray diffraction (XRD), UV-visible spectroscopy, Fourier
Transform infrared (FTIR) spectroscopy and photolumnisce spectroscopy.