Electronic, Energetic and Chemical Effects of Intrinsic Defects and Fe-Doping of CoAl2O4: A DFT+U Study
The spinel cobalt aluminate has gained interest as a potential photoelectrochemical catalyst for the renewable production of hydrogen. Using band structure theory, we determine the energetics of possible intrinsic point defects in spinel CoAl{sub 2}O{sub 4} and analyze their effect on its electronic and chemical properties. Extrinsic Fe-doping is also examined. Cation vacancies are found to be shallow acceptors, but their formation energy is sensitive to the growth conditions; an oxygen rich environment is required to enhance the p-type conductivity. Fe is an isovalent substituent on the Co (Al) site, exhibiting a preference for octahedral coordination, and forms a deep donor (acceptor) level near the center of the band gap, corresponding to a Fe(II) to Fe(III) transition.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC36-99-GO10337
- OSTI ID:
- 940589
- Journal Information:
- Journal of Physical Chemistry C, Vol. 112, Issue 2008; ISSN 1932-7447
- Country of Publication:
- United States
- Language:
- English
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