Physical properties of anatase TiO2 altered by lanthanide atoms

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2015

Öğrenci: KIVILCIM BAŞAK VURAL

Danışman: SÜLEYMAN ŞİNASİ ELLİALTIOĞLU

Özet:

In this thesis, the structural, electronic and optical properties of adsorption of single lanthanide atoms (Pr, Gd, Er, and Lu) in anatase TiO2 (101) substrate have been investigated by using the first-principles calculations based on Hubbard U corrected term density functional theory (DFT+U). Here, among the lanthanides, we have primarily concentrated on Pr atom. TiO2 has attracted a material in various technological applications due to its chemical stability. In most of the technological applications such as photocatalytic TiO2 have been used to relate to its physical properties. Lanthanides (Ln) have drawn the attention as good dopants because of the improved features of TiO2. The strong correlations are arising from the localized Ti 3d and lanthanide (Ln) 4f orbitals. This indicates that the doping process do occur easily. The adsorption energies of Pr atom are found high in all binding models, so Pr is effective atom for adsorption process. The result of interaction between Ln and the surface, impurity states occur into the band gap, this provide the optical activity of the TiO2 (101) surface with improving both the UV-visible and the near-IR range. Also, we have studied adsorbate-dopant interaction using prototypical dye molecules such as benzoic acid and Coumarin 153. Molecular adsorption energies and the optical properties are improved by the presence of Ln. In addition, considering the interaction between Coumarin 153 (C153) and reduced (O-vacancy) surfaces, it seems to be an effective method as much as.