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arXiv · 1403.5525

Tuning the Electronic Structure of Anatase Through Fluorination

Dario Corradini·Damien Dambournet·Mathieu Salanne
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Abstract

A highly fluorinated anatase lattice has been recently reported, providing a new class of materials whose general chemical formula is $\rm Ti_{1- \mathit x}\square_{\mathit x}X_{4\mathit x}O_{2- 4\mathit x}$ (X$^-$ = F$^-$ or OH$^-$). To characterise the complex structural features of the material and the different F environments, we here apply a computational screening procedure. After deriving a polarisable force--field from DFT simulations, we screen in a step-wise fashion a large number of possible configurations differing in the positioning of the titanium vacancies ($\square$) and of the fluorine atoms. At each step only 10% of the configurations are retained. At the end of the screening procedure, a configuration is selected and simulated using DFT-based molecular dynamics. This allows us to analyse the atomic structure of the material, which is strongly disordered, leading to a strong decrease (by 0.8~eV) of the band gap compared to conventional anatase.

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Dario Corradini, Damien Dambournet, Mathieu Salanne. 2014-03-21. Tuning the Electronic Structure of Anatase Through Fluorination. https://doi.org/10.1038/srep11553

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