Photoelectrochemical Behavior of n-Type GaAs(100) Electrodes Coated by a Single Layer of Graphene

Fan Yang, Adam C. Nielander, Ronald L. Grimm, Nathan S Lewis

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

The photoelectrochemical behavior of n-type GaAs(100) electrodes coated with a single layer of graphene was compared with the behavior of bare, freshly etched n-type GaAs(100) electrodes, both for electrodes in contact with an aqueous solution containing K3[Fe(CN)6]/K4[Fe(CN)6] and for electrodes in contact with nonaqueous solutions containing a series of one-electron redox couples selected such that the Nernstian solution potentials spanned a range greater than 1 V. Under simulated 1 Sun illumination, the graphene-coated electrodes produced a short-circuit photocurrent density of 20 mA cm-2 for up to 8 h of continuous operation in nonaqueous electrolytes (H2O concentration 0.1%, v/v), while, under the same conditions, the unprotected n-GaAs electrodes showed a rapid decay of the photocurrent density within ∼400 s. Although the graphene monolayers enhanced the stability of n-GaAs photoanodes in nonaqueous electrolytes, the graphene did not fully protect photoanodes operated in contact with Fe(CN)6 3-/4-(aq) from corrosion. The dependence of the open-circuit voltage measured for graphene-coated n-GaAs photoanodes on the Nernstian potential of the solution was effectively identical to that of freshly etched n-GaAs photoanodes, indicating that addition of the graphene layer did not introduce significant pinning of the Fermi level of GaAs beyond the Fermi-level pinning attributable to mid-gap and solution-derived charge-carrier trap states previously observed at GaAs/liquid junctions.

Original languageEnglish
Pages (from-to)6989-6995
Number of pages7
JournalJournal of Physical Chemistry C
Volume120
Issue number13
DOIs
Publication statusPublished - Apr 21 2016

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Graphene
graphene
Electrodes
electrodes
nonaqueous electrolytes
Fermi level
Photocurrents
Contacts (fluid mechanics)
photocurrents
Electrolytes
short circuits
Open circuit voltage
open circuit voltage
Charge carriers
Short circuit currents
Sun
gallium arsenide
charge carriers
Monolayers

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Photoelectrochemical Behavior of n-Type GaAs(100) Electrodes Coated by a Single Layer of Graphene. / Yang, Fan; Nielander, Adam C.; Grimm, Ronald L.; Lewis, Nathan S.

In: Journal of Physical Chemistry C, Vol. 120, No. 13, 21.04.2016, p. 6989-6995.

Research output: Contribution to journalArticle

Yang, Fan ; Nielander, Adam C. ; Grimm, Ronald L. ; Lewis, Nathan S. / Photoelectrochemical Behavior of n-Type GaAs(100) Electrodes Coated by a Single Layer of Graphene. In: Journal of Physical Chemistry C. 2016 ; Vol. 120, No. 13. pp. 6989-6995.
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