The electronic structure and optical response of rutile, anatase and brookite TiO₂

Abstract

In this study, we present a combined density functional theory and many-body perturbation theory study on the electronic and optical properties of TiO(2) brookite as well as the tetragonal phases rutile and anatase. The electronic structure and linear optical response have been calculated from the Kohn-Sham band structure applying (semi)local as well as nonlocal screened hybrid exchange-correlation density functionals. Single-particle excitations are treated within the GW approximation for independent quasiparticles. For optical response calculations, two-particle excitations have been included by solving the Bethe-Salpeter equation for Coulomb correlated electron-hole pairs. On this methodological basis, gap data and optical spectra for the three major phases of TiO(2) are provided. The common characteristics of brookite with the rutile and anatase phases, which have been discussed more comprehensively in the literature, are highlighted. Furthermore, the comparison of the present calculations with measured optical response data of rutile indicate that discrepancies discussed in numerous earlier studies are due to the measurements rather than related to an insufficient theoretical description.

Rutile TiO2 films as electron transport layer in inverted organic solar cell

“…Usually rutile phase has a band gap higher than 3eV, however the differences in our results have been correlated to the structure properties which lead to different electronic configuration; where the Ti-Ti and Ti-O distances in TiO 2 structure are different between anatase and rutile phase [30].…”

Electronic and magnetic properties ofTi4O7predicted by self-interaction-corrected density functional theory

“…Therefore, understanding the behavior of Ti-O based structures that depends on the Ti oxidation states requires detailed knowledge of electronic properties of the different sub-stoichiometric phases of titanium oxide. From a theoretical and modeling point of view, it is known 7,12,13 that density functional theory (DFT) using the conventional local density approximation (LDA) or generalized gradient approximation (GGA) does not yield an accurate description of the electronic structure (e.g., band gap, or location of defect states within the band gap) of pristine and oxygen-deficient TiO 2 . Recently, DFT methods beyond conventional DFT, specifically the LDA+U method 14 as well as hybrid functionals 15 , have been used to study TiO 2 , yielding in general satisfactory results.…”

Characterization of Titanium Dioxide by Microwave Assisted Homogeneous Precipitation

“…It is well known that rutile is the stable phase because of different distortion degree and connection mode (two edges are shared in rutile, four edges in anatase) while anatase shows higher photocatalytic activity due to the lower recombination rate of photogenerated electron-hole pair than rutile and has high adsorption capacity towards organic contaminates [1]. Numerous efforts have been devoted to synthesize TiO2 with different morphology including sol-gel process, hydrothermal treatment, micro-emulsion and anodization method [2].…”