The oxygen vacancy in crystal phases of WO3

Chadwick, A.V. and Chatten, R. and Rougier, A. and Lindan, P.J.D. (2005) The oxygen vacancy in crystal phases of WO3. JOURNAL OF PHYSICAL CHEMISTRY B , 109 (8). pp. 3146-3156. ISSN 1520-6106. (Access to this publication is restricted)

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Abstract

The oxygen vacancy in WO3 has previously been implicated in the electrochromism mechanism in this material. Previous theoretical calculations on the oxygen vacancy in WO3 have not considered the full range of crystal structures adopted by the material. Here we report studies of the oxygen vacancy in seven crystal phases. The use of a very accurate tungsten plane-wave pseudopotential means that a byproduct of this study is a more detailed and complete picture of undefected WO3 than previously available. Electronic structures of the crystal phases in both undefected and defected systems have been calculated and are discussed. The band gap in WO3 is dependent upon bonding - antibonding interactions, these being dependent upon overlap in each direction. The effect of an oxygen vacancy is dependent upon the availability of both Op and Wd electrons, this being different for the various phases. A variety of behavior is predicted, which may be explained in terms of O2p-W5d mixing, including the formation of long W-W dimer bonds. It is found that the nature of a polaron in this material is dependent upon both the crystal structure and distribution of oxygen vacancies.

Item Type: Article
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Physical Sciences
Depositing User: Alan Chadwick
Date Deposited: 13 Sep 2008 18:47
Last Modified: 24 Apr 2012 09:02
Resource URI: http://kar.kent.ac.uk/id/eprint/8399 (The current URI for this page, for reference purposes)
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