Surface-Mediated Charge Transfer of Photogenerated Carriers in Diamond

Arsène Chemin, Igal Levine, Marin Rusu, Rémi Vaujour, Peter Knittel, Philipp Reinke, Karsten Hinrichs, Thomas Unold, Thomas Dittrich, Tristan Petit*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

Solvated electrons are highly reductive chemical species whose chemical properties remain largely unknown. Diamond materials are proposed as a promising emitter of solvated electrons and visible light excitation would enable solar-driven CO2 or N2 reductions reactions in aqueous medium. But sub-bandgap excitation remains challenging. In this work, the role of surface states on diamond materials for charge separation and emission in both gaseous and aqueous environments from deep UV to visible light excitation is elucidated. Four different X-ray and UV–vis spectroscopy methods are applied to diamond materials with different surface termination, doping and crystallinity. Surface states are found to dominate sub-bandgap charge transfer. However, the surface charge separation is drastically reduced for boron-doped diamond due to a very high density of bulk defects. In a gaseous atmosphere, the oxidized diamond surface maintains a negative electron affinity, allowing charge emission, due to remaining hydrogenated and hydroxylated groups. In an aqueous electrolyte, a photocurrent for illumination down to 3.5 eV is observed for boron-doped nanostructured diamond, independent of the surface termination. This study opens new perspectives on photo-induced interfacial charge transfer processes from metal-free semiconductors such as diamonds.

Original languageEnglish
Article number2300423
JournalSmall Methods
Volume7
Issue number11
DOIs
StatePublished - 16 Nov 2023
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Small Methods published by Wiley-VCH GmbH.

Keywords

  • photocurrent spectroscopy
  • photoelectron yield spectroscopy
  • surface chemistry
  • surface photovoltage
  • X-ray absorption spectroscopy

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