Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering

Ahmed S.M. Ismail; Yohei Uemura; Sang Han Park; Soonnam Kwon; Minseok Kim; Hebatalla Elnaggar; Federica Frati; Yasuhiro Niwa; Hiroki Wadati; Yasuyuki Hirata; Yujun Zhang; Kohei Yamagami; Susumu Yamamoto; Iwao Matsuda; Ufuk Halisdemir; Gertjan Koster; Bert M. Weckhuysen; Frank M.F. de Groot

doi:10.1039/c9cp03374b

Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering

Ahmed S.M. Ismail, Yohei Uemura, Sang Han Park, Soonnam Kwon, Minseok Kim, Hebatalla Elnaggar, Federica Frati, Yasuhiro Niwa, Hiroki Wadati, Yasuyuki Hirata, Yujun Zhang, Kohei Yamagami, Susumu Yamamoto, Iwao Matsuda, Ufuk Halisdemir, Gertjan Koster, Bert M. Weckhuysen, Frank M.F. de Groot^*

^*Corresponding author for this work

Inorganic Materials Science

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Abstract

Hematite, α-Fe₂O₃, is an important semiconductor for photoelectrochemical water splitting. Its low charge carrier mobility and the presence of midgap states provide favourable conditions for electron-hole recombination, hence affecting the semiconductor's photoelectrochemical efficiency. The nature of the excited state and charge carrier transport in hematite is strongly debated. In order to further understand the fundamental properties of the hematite photoexcited state, we conducted femtosecond 2p (L₃) X-ray absorption (XAS) and 2p3d resonant inelastic scattering (RIXS) measurements on hematite thin-films at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). The observed spectral changes and kinetic processes are in agreement with previous 3p XAS reports. The potential additional information that could be acquired from 2p3d RIXS experiments is also discussed.

Original language	English
Pages (from-to)	2685-2692
Number of pages	8
Journal	Physical chemistry chemical physics
Volume	22
Issue number	5
DOIs	https://doi.org/10.1039/c9cp03374b
Publication status	Published - 7 Feb 2020

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Ismail, A. S. M., Uemura, Y., Park, S. H., Kwon, S., Kim, M., Elnaggar, H., Frati, F., Niwa, Y., Wadati, H., Hirata, Y., Zhang, Y., Yamagami, K., Yamamoto, S., Matsuda, I., Halisdemir, U., Koster, G., Weckhuysen, B. M., & de Groot, F. M. F. (2020). Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering. Physical chemistry chemical physics, 22(5), 2685-2692. https://doi.org/10.1039/c9cp03374b

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title = "Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering",

abstract = "Hematite, α-Fe2O3, is an important semiconductor for photoelectrochemical water splitting. Its low charge carrier mobility and the presence of midgap states provide favourable conditions for electron-hole recombination, hence affecting the semiconductor's photoelectrochemical efficiency. The nature of the excited state and charge carrier transport in hematite is strongly debated. In order to further understand the fundamental properties of the hematite photoexcited state, we conducted femtosecond 2p (L3) X-ray absorption (XAS) and 2p3d resonant inelastic scattering (RIXS) measurements on hematite thin-films at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). The observed spectral changes and kinetic processes are in agreement with previous 3p XAS reports. The potential additional information that could be acquired from 2p3d RIXS experiments is also discussed.",

author = "Ismail, {Ahmed S.M.} and Yohei Uemura and Park, {Sang Han} and Soonnam Kwon and Minseok Kim and Hebatalla Elnaggar and Federica Frati and Yasuhiro Niwa and Hiroki Wadati and Yasuyuki Hirata and Yujun Zhang and Kohei Yamagami and Susumu Yamamoto and Iwao Matsuda and Ufuk Halisdemir and Gertjan Koster and Weckhuysen, {Bert M.} and {de Groot}, {Frank M.F.}",

year = "2020",

month = feb,

day = "7",

doi = "10.1039/c9cp03374b",

language = "English",

volume = "22",

pages = "2685--2692",

journal = "Physical chemistry chemical physics",

issn = "1463-9076",

publisher = "Royal Society of Chemistry",

number = "5",

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Ismail, ASM, Uemura, Y, Park, SH, Kwon, S, Kim, M, Elnaggar, H, Frati, F, Niwa, Y, Wadati, H, Hirata, Y, Zhang, Y, Yamagami, K, Yamamoto, S, Matsuda, I, Halisdemir, U, Koster, G, Weckhuysen, BM & de Groot, FMF 2020, 'Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering', Physical chemistry chemical physics, vol. 22, no. 5, pp. 2685-2692. https://doi.org/10.1039/c9cp03374b

Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering. / Ismail, Ahmed S.M.; Uemura, Yohei; Park, Sang Han et al.
In: Physical chemistry chemical physics, Vol. 22, No. 5, 07.02.2020, p. 2685-2692.

Research output: Contribution to journal › Article › Academic › peer-review

TY - JOUR

T1 - Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering

AU - Ismail, Ahmed S.M.

AU - Uemura, Yohei

AU - Park, Sang Han

AU - Kwon, Soonnam

AU - Kim, Minseok

AU - Elnaggar, Hebatalla

AU - Frati, Federica

AU - Niwa, Yasuhiro

AU - Wadati, Hiroki

AU - Hirata, Yasuyuki

AU - Zhang, Yujun

AU - Yamagami, Kohei

AU - Yamamoto, Susumu

AU - Matsuda, Iwao

AU - Halisdemir, Ufuk

AU - Koster, Gertjan

AU - Weckhuysen, Bert M.

AU - de Groot, Frank M.F.

PY - 2020/2/7

Y1 - 2020/2/7

N2 - Hematite, α-Fe2O3, is an important semiconductor for photoelectrochemical water splitting. Its low charge carrier mobility and the presence of midgap states provide favourable conditions for electron-hole recombination, hence affecting the semiconductor's photoelectrochemical efficiency. The nature of the excited state and charge carrier transport in hematite is strongly debated. In order to further understand the fundamental properties of the hematite photoexcited state, we conducted femtosecond 2p (L3) X-ray absorption (XAS) and 2p3d resonant inelastic scattering (RIXS) measurements on hematite thin-films at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). The observed spectral changes and kinetic processes are in agreement with previous 3p XAS reports. The potential additional information that could be acquired from 2p3d RIXS experiments is also discussed.

AB - Hematite, α-Fe2O3, is an important semiconductor for photoelectrochemical water splitting. Its low charge carrier mobility and the presence of midgap states provide favourable conditions for electron-hole recombination, hence affecting the semiconductor's photoelectrochemical efficiency. The nature of the excited state and charge carrier transport in hematite is strongly debated. In order to further understand the fundamental properties of the hematite photoexcited state, we conducted femtosecond 2p (L3) X-ray absorption (XAS) and 2p3d resonant inelastic scattering (RIXS) measurements on hematite thin-films at the Pohang Accelerator Laboratory X-ray Free Electron Laser (PAL-XFEL). The observed spectral changes and kinetic processes are in agreement with previous 3p XAS reports. The potential additional information that could be acquired from 2p3d RIXS experiments is also discussed.

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U2 - 10.1039/c9cp03374b

DO - 10.1039/c9cp03374b

M3 - Article

C2 - 31641716

AN - SCOPUS:85079023425

SN - 1463-9076

VL - 22

SP - 2685

EP - 2692

JO - Physical chemistry chemical physics

JF - Physical chemistry chemical physics

IS - 5

ER -

Direct observation of the electronic states of photoexcited hematite with ultrafast 2p3d X-ray absorption spectroscopy and resonant inelastic X-ray scattering

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