Issue 1, 2015

Oxygen vacancy and hole conduction in amorphous TiO2

Abstract

The amorphous titanium dioxide (a-TiO2) has drawn attention recently due to the finding that it holds promise for coating conventional photoelectrodes for corrosion protection while still allowing the holes to transport to the surface. The mechanism of hole conductivity at a level much higher than the edge of the valence band is still a mystery. In this work, an amorphous TiO2 model is obtained from molecular dynamics employing the “melt-and-quench” technique. The electronic properties, polaronic states and the hole conduction mechanism in amorphous structure were investigated by means of density functional theory with Hubbard's energy correction (DFT + U) and compared to those in crystalline (rutile) TiO2. The formation energy of the oxygen vacancy was found to reduce significantly (by a few eV) upon amorphization. Our theoretical study suggested that the oxygen vacancies and their defect states provide hopping channels, which are comparable to experimental observations and could be responsible for hole conduction in the “leaky” TiO2 recently discovered for the photochemical water-splitting applications.

Graphical abstract: Oxygen vacancy and hole conduction in amorphous TiO2

Supplementary files

Article information

Article type
Paper
Submitted
18 Sep 2014
Accepted
05 Nov 2014
First published
05 Nov 2014

Phys. Chem. Chem. Phys., 2015,17, 541-550

Author version available

Oxygen vacancy and hole conduction in amorphous TiO2

H. H. Pham and L. Wang, Phys. Chem. Chem. Phys., 2015, 17, 541 DOI: 10.1039/C4CP04209C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements