Photocurrent Enhancement by Spontaneous Formation of a p–n Junction in Calcium-Doped Bismuth Vanadate Photoelectrodes

Fatwa F. Abdi*, David E. Starr, Ibbi Y. Ahmet, Roel van de Krol

*Corresponding author for this work

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

15 Citations (Scopus)

Abstract

The application of bismuth vanadate (BiVO<sub>4</sub>) photoelectrodes for solar water splitting is hindered by the poor carrier transport. To overcome this, multiple donor-doping strategies (e.g. dual doping, gradient doping) have been explored. Here, we show for the first time the successful introduction of calcium (Ca) as an acceptor-type dopant into BiVO<sub>4</sub> photoelectrodes. Interestingly, instead of generating cathodic photocurrents, the Ca-doped BiVO<sub>4</sub> photoelectrodes show anodic photocurrents with an enhanced carrier separation efficiency. Hard X-ray photoelectron spectroscopy (HAXPES) shows that this enhancement is caused by out-diffusion of Ca during the deposition process, which spontaneously creates a p–n junction within the BiVO<sub>4</sub> layer. Overall, a significant two-fold improvement of the AM1.5 photocurrent is obtained upon Ca-doping. This study highlights the importance of controlled doping beyond simply modifying carrier concentration and may enable new device architectures in photoelectrode materials. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Original languageEnglish
Pages (from-to)941-946
JournalChemPlusChem
Volume83
Issue number10
DOIs
Publication statusPublished - 1 Oct 2018
Externally publishedYes

Bibliographical note

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Research Keywords

  • BiVO4
  • photoelectrodes
  • p–n junction
  • solar water splitting

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