TY - JOUR
T1 - Surface-Mediated Charge Transfer of Photogenerated Carriers in Diamond
AU - Chemin, Arsène
AU - Levine, Igal
AU - Rusu, Marin
AU - Vaujour, Rémi
AU - Knittel, Peter
AU - Reinke, Philipp
AU - Hinrichs, Karsten
AU - Unold, Thomas
AU - Dittrich, Thomas
AU - Petit, Tristan
N1 - Publisher Copyright:
© 2023 The Authors. Small Methods published by Wiley-VCH GmbH.
PY - 2023/11/16
Y1 - 2023/11/16
N2 - 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.
AB - 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.
KW - photocurrent spectroscopy
KW - photoelectron yield spectroscopy
KW - surface chemistry
KW - surface photovoltage
KW - X-ray absorption spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85168379177&partnerID=8YFLogxK
U2 - 10.1002/smtd.202300423
DO - 10.1002/smtd.202300423
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C2 - 37596059
AN - SCOPUS:85168379177
SN - 2366-9608
VL - 7
JO - Small Methods
JF - Small Methods
IS - 11
M1 - 2300423
ER -