Ella C Linganiso, Sefako J Mofokeng, Vinod Kumar, Robin E Kroon and Odireleng M Ntwaeaborwa
University of the Free State, South Africa
Posters & Accepted Abstracts: J Nanomed Nanotechnol
Down-conversion in nanomaterial phosphors doped with Rare Earth (RE) ions is currently being explored for solar cell applications. This is inspired by the ability of RE elements to luminescence over a wide range, from the near-infrared, through visible to the ultra-violet wavelength energy regions, whilst exhibiting only weak interactions with the host lattice. Titanium dioxide (TiO2), zinc oxide (ZnO), europium (Eu3+) and dysprosium (Dy3+) individually show excellent luminescence properties. In this report, ZnO and TiO2 nano-based composite phosphor was activated with different concentrations of Eu3+ and Dy3+ fabricated using the sol-gel method of synthesis such that, ZnO-TiO2: xDy3+ and yEu3+ (x=0.4 and y=0.05 to 0.75 mol). The prepared phosphors were characterized by X-ray Diffraction (XRD) technique for confirmation of the formation of the desired product, crystallinity and product phase purity. The XRD patterns confirmed crystallization of wurtzite hexagonal ZnO and tetragonal TiO2 (anatase and rutile) phases. In addition, the XRD data confirmed that secondary phases of ZnTiO3 and Zn2TiO4 were also formed. Morphological analysis was carried out using scanning electron microscopy (SEM), and formation of nanoflake-like structures, nanorods and uniformly distributed structures was confirmed. Photoluminescence characterization of the as-prepared phosphors was carried out under UV excitation at 248 nm and the prominent emission bands were observed in the visible region at 496, 584, 593 and 614 nm, corresponding to transitions of Dy3+ and Eu3+ ions. The energy transfer mechanism between the ZnO-TiO2 host and dopants (Dy3+ and Eu3+) is discussed.