Phosphonic Acid Modification of GaInP2 Photocathodes Toward Unbiased Photoelectrochemical Water Splitting

Bradley A. Macleod, K. Xerxes Steirer, James L. Young, Unsal Koldemir, Alan Sellinger, John A. Turner, Todd G. Deutsch, Dana C. Olson

Research output: Contribution to journalArticlepeer-review

62 Scopus Citations


The p-type semiconductor GaInP2 has a nearly ideal bandgap (∼1.83 eV) for hydrogen fuel generation by photoelectrochemical water splitting but is unable to drive this reaction because of misalignment of the semiconductor band edges with the water redox half reactions. Here, we show that attachment of an appropriate conjugated phosphonic acid to the GaInP2 electrode surface improves the band edge alignment, closer to the desired overlap with the water redox potentials. We demonstrate that this surface modification approach is able to adjust the energetic position of the band edges by as much as 0.8 eV, showing that it may be possible to engineer the energetics at the semiconductor/electrolyte interface to allow for unbiased water splitting with a single photoelectrode having a bandgap of less than 2 eV.

Original languageAmerican English
Pages (from-to)11346-11350
Number of pages5
JournalACS Applied Materials and Interfaces
Issue number21
StatePublished - 2015

Bibliographical note

Publisher Copyright:
© 2015 American Chemical Society.

NREL Publication Number

  • NREL/JA-5900-63712


  • gallium indium phosphide (GaInP)
  • InGaP
  • precision control of semiconductor interfacial energetics to enable photocatalysis
  • water splitting


Dive into the research topics of 'Phosphonic Acid Modification of GaInP2 Photocathodes Toward Unbiased Photoelectrochemical Water Splitting'. Together they form a unique fingerprint.

Cite this