Investigating Polaron Formation in Anatase and Brookite TiO₂ by Density Functional Theory with Hybrid-Functional and DFT + U Methods.

ABSTRACT: Anatase and brookite are robust materials with enhanced photocatalytic properties. In this study, we used density functional theory (DFT) with a hybrid functional and the Hubbard on-site potential methods to determine electron- and hole-polaron geometries for anatase and brookite and their energetics. Localized electron and hole polarons were predicted not to form in anatase using DFT with hybrid functionals. In contrast, brookite formed both electron and hole polarons. The brookite electron-polaronic solution exhibits coexisting localized and delocalized states, with hole polarons mainly dispersed on two-coordinated oxygen ions. Hubbard on-site potential testing over the wide 4.0-10 eV range revealed that brookite polarons are formed at U = 6 eV, while anatase polarons are formed a

SUBMITTER: De Lile JR 

PROVIDER: S-EPMC6648264 | biostudies-literature | 2019 May

REPOSITORIES: biostudies-literature