Delafossite-alloy photoelectrodes for PEC hydrogen production: a density functional theory study

M N Huda, Y F Yan, Aron Walsh, S H Wei, J A Turner, M M Al-Jassim

Research output: Chapter in Book/Report/Conference proceedingChapter

2 Citations (Scopus)

Abstract

Efficient photo-electrochemical (PEC) splitting of water to hydrogen usually requires photoelectrodes to have certain electronic properties. Unfortunately, at present available semiconductors do not meet all these criteria. So, a thorough understanding of band-engineering for mixed alloys is necessary to successfully design these photoelectrodes. Among the semiconductors, transition metal oxides are of particular interest due to their low cost and relatively high stability in aqueous media. Here, we will present a theoretical study of delafossite-alloys for PEC photo-electrodes. Previous studies have indicated that the group IIIA delafossite family (CuMO(2), M = Al, Ga, In) do not exhibit direct band gaps. Their fundamental band gaps are significantly smaller than their reported optical band gaps. On the other hand group IIIB delafossite family (CuMO(2), M = Sc, Y, La) in general show direct band gaps and, except for CuLaO(2), band gaps are above 3.00 eV. However, both of these two families exhibit p-type conductivity. We will show that by appropriate alloying of these two delafossite-families we can tune their band gaps and other opto-electronic properties. These types of alloying are desirable, as these introduce no localized impurity states in the band gap due to isovalent alloying. Also, the electronic effective masses can be lowered by selective doping of main group elements. Finally, it will be discussed that, lowering the symmetry constraints of these alloys would enhance their optical absorption properties. We'll also discuss that alloying with other 3d metal elements may decrease the band gap, but would increase the effective masses of the photo-electrons.
Original languageEnglish
Title of host publicationSolar Hydrogen and Nanotechnology V
EditorsH Idriss, H Wang
Place of PublicationBellingham
PublisherSPIE
Pages77700F
Volume7770
Edition77700F
ISBN (Print)978-0-8194-8266-2
DOIs
Publication statusPublished - 2010

Publication series

NameProceedings of SPIE-The International Society for Optical Engineering
PublisherSpie-Int Soc Optical Engineering

Keywords

  • water
  • wave basis-set
  • total-energy calculations
  • generation

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    Huda, M. N., Yan, Y. F., Walsh, A., Wei, S. H., Turner, J. A., & Al-Jassim, M. M. (2010). Delafossite-alloy photoelectrodes for PEC hydrogen production: a density functional theory study. In H. Idriss, & H. Wang (Eds.), Solar Hydrogen and Nanotechnology V (77700F ed., Vol. 7770, pp. 77700F). (Proceedings of SPIE-The International Society for Optical Engineering). SPIE. https://doi.org/10.1117/12.859947