A Comparison Between Hybrid Functional, GW Approach and the Bethe Salpether Equation: Optical Properties of High Pressure Phases of TiO2
2014 (English)In: Science of Advanced Materials, ISSN 1947-2935, Vol. 6, no 6, 1170-1178 p.Article in journal (Refereed) Published
Titanium dioxide has good corrosion resistance in aqueous solutions and is a good candidate for photoelectrodes. The limitation of the anatase phase of TiO2 is its large band gap. High pressure phases of TiO2 like fluorite, pyrite and cotunnite may possess a more suitable band gap than the well known atmospheric phases. In this paper, the electronic properties of high pressure phases of TuO(2), fluorite, pyrite and cotunnite, have been investigated by hybrid functional and GW methods. Our calculations suggest that the band gap of fluorite and pyrite phases have optimal band gaps to absorb visible light for photocatalysis to decompose water. The imaginary part of the dielectric function has also been calculated for fluorite, pyrite, cotunnite and anatase phases using the Bethe-Salpether (BSE) method. The dielectric function calculated by BSE for the anatase phase agrees well with experiment and with previous studies, using the same level of theory. Therefore we expect that we are also able to predict the optical properties of the high pressure phases of TiO2 by the BSE method. The spatial properties and the localization character of excitons in these high pressure phases were investigated and discussed in terms of photoconversion efficiency.
Place, publisher, year, edition, pages
2014. Vol. 6, no 6, 1170-1178 p.
High Pressure, Titanium Dioxide, Hybrid Functional, GW, BSE
Nano Technology Physical Sciences
IdentifiersURN: urn:nbn:se:uu:diva-228551DOI: 10.1166/sam.2014.1883ISI: 000337268100012OAI: oai:DiVA.org:uu-228551DiVA: diva2:734455