Using DFTB to Model Photocatalytic Anatase–Rutile TiO₂ Nanocrystalline Interfaces and Their Band Alignment

Abstract

Band alignment effects of anatase and rutile nanocrystals in TiO 2 powders lead to electron–hole separation, increasing the photocatalytic efficiency of these powders. While size effects and types of possible alignments have been extensively studied, the effect of interface geometries of bonded nanocrystal structures on the alignment is poorly understood. To allow conclusive studies of a vast variety of bonded systems in different orientations, we have developed a new density functional tight-binding parameter set to properly describe quantum confinement in nanocrystals. By applying this set, we found a quantitative influence of the interface structure on the band alignment.

Water Reactions on Reconstructed Rutile TiO2: A Density Functional Theory/Density Functional Tight Binding Approach

“…Unfortunately, however, the current parameter sets fail in predicting the correct range of thermodynamic stability of this surface and also in reproducing the structural atomic arrangement obtained by DFT. In order to overcome the problems experienced with the Tiorg and Tiorg-smooth Slater–Koster sets, a new DFTB parametrization is being currently developed . It offers a better description of the electronic part of the Ti–O interaction as it uses the more recent 3ob organic set for the description of the oxygen atoms.…”

Water reactions on reconstructed rutile TiO$_2$: a DFT / DFTB approach

“…In order to overcome the problems experienced with the Tiorg and Tiorg-smooth SK-sets, a new DFTB parametrization is being currently developed. 75 It offers a better description of the electronic part of the Ti-O interaction as it uses the more recent 3ob organic set 76 for the description of the oxygen atoms. Additionally, it introduces three-body terms in the repulsive energy, resulting in an improved representation of undercoordinated Ti atoms on various TiO 2 surfaces.…”

Sustainable Sol‐Gel Approach for Visible Light‐Responsive Titanium Dioxide Nanoparticles in Efficient Diazinon Removal

“…Also, Arrigoni and Madsen utilized DFT+U, screened hybrid functionals, and varied supercell sizes to study defect chemistry in TiO₂ anatase, analyzing native point defects and their charge transition levels [16] . Meanwhile, Gupta and co‐workers employed DFTB to investigate nanocrystalline interfaces in anatase and rutile phases, focusing on photocatalysis and band alignment determination [17] …”

“…[16] Meanwhile, Gupta and co-workers employed DFTB to investigate nanocrystalline interfaces in anatase and rutile phases, focusing on photocatalysis and band alignment determination. [17] Besides, Çetin and co-researchers used DFT + U and DFTB to compute chemical descriptors for TiO 2 surfaces, specifically examining oxygen vacancy formation energy and electronic structure to understand surface reactivity. [18] Furthermore, Zeng and co-workers utilized DFT calculations, employing PBE exchange-correlation functional and the projector-augmented wave (PAW) method, to explore the optical spectrum of N/Pdoped TiO 2 -anatase.…”