TY - JOUR
T1 - Wavelength Dependent Photocurrent of Hematite Photoanodes
T2 - Reassessing the Hole Collection Length
AU - Kay, Asaf
AU - Grave, Daniel A.
AU - Deo Malviya, Kirtiman
AU - Ellis, David S.
AU - Dotan, Hen
AU - Rothschild, Avner
N1 - Funding Information:
This research has received funding from the European Research Council under the European Union’s Seventh Framework programme (FP/200702013)/ERC Grant Agreement No. [617516]. D.A.G. acknowledges support by Marie-Sklodowska-Curie Individual Fellowship No. 659491. The results were obtained using central facilities at the Technion’s Hydrogen Technologies Research Laboratory (HTRL), supported by the Adelis Foundation, the Nancy & Stephen Grand Technion Energy Program (GTEP), and by the Solar Fuels I-CORE program of the Planning and Budgeting Committee and the Israel Science Foundation (Grant No. 152/11). K. D. Malviya acknowledges support in part at the Technion by a fellowship from the Lady Davis Foundation. D. S. Ellis acknowledges support from The Center for Absorption in Science at the Ministry of Aliyah and Immigrant Absorption. The authors acknowledge support by the electron microscopy center of Technion (MIKA).
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/12/28
Y1 - 2017/12/28
N2 - The photoelectrochemical behavior of a planar 1 μm thick Ti-doped hematite film deposited on F:SnO2 coated glass was studied with both front and back illumination. Despite low quantum efficiency, photocurrent was observed upon back illumination with low wavelengths, indicating that some photogenerated holes are able to traverse at least 700 nm across the hematite film and effectively oxidize water. This cannot be accounted for using the commonly accepted hole collection length of hematite based on fitting to the Gartner model. Furthermore, under back illumination, 450 nm excitation resulted in increased photocurrent as compared to 530 nm excitation despite most of the light being absorbed further away from the surface. These results demonstrate that the photocurrent is strongly dependent on the optical excitation wavelength and related to both delocalized holes with long lifetime and localized excitations rather than only being dependent on the proximity of the absorption to the surface.
AB - The photoelectrochemical behavior of a planar 1 μm thick Ti-doped hematite film deposited on F:SnO2 coated glass was studied with both front and back illumination. Despite low quantum efficiency, photocurrent was observed upon back illumination with low wavelengths, indicating that some photogenerated holes are able to traverse at least 700 nm across the hematite film and effectively oxidize water. This cannot be accounted for using the commonly accepted hole collection length of hematite based on fitting to the Gartner model. Furthermore, under back illumination, 450 nm excitation resulted in increased photocurrent as compared to 530 nm excitation despite most of the light being absorbed further away from the surface. These results demonstrate that the photocurrent is strongly dependent on the optical excitation wavelength and related to both delocalized holes with long lifetime and localized excitations rather than only being dependent on the proximity of the absorption to the surface.
UR - http://www.scopus.com/inward/record.url?scp=85037557981&partnerID=8YFLogxK
U2 - 10.1021/acs.jpcc.7b09472
DO - 10.1021/acs.jpcc.7b09472
M3 - Article
AN - SCOPUS:85037557981
VL - 121
SP - 28287
EP - 28292
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
SN - 1932-7447
IS - 51
ER -