TY - JOUR
T1 - External Quantum Efficiency Spectra of BiVO4Thin Film Photoanodes under Bias Illumination
AU - Piekner, Yifat
AU - Ellis, David S.
AU - Schleuning, Markus
AU - Grave, Daniel A.
AU - Schnell, Patrick
AU - Dotan, Hen
AU - Abdi, Fatwa F.
AU - Rothschild, Avner
N1 - Funding Information:
The research leading to these results was supported by the Israel Science Foundation through the PAT Center of Research Excellence and Grant No. 1867/17. The EQE and optical measurements were carried out at the Technion’s Photovoltaics Laboratory (HTRL), supported by the RBNI, the Nancy and Stephen Grand Technion Energy Program (GTEP) and the Adelis Foundation. Part of this research was carried out within the Helmholtz International Research School ‘Hybrid Integrated Systems for Conversion of Solar Energy’ (HI-SCORE), an initiative co-funded by the Initiative and Networking Fund of the Helmholtz Association. D.A.G. acknowledges support from the Center for Absorption in Science of the Ministry of Aliyah and Immigrant Absorption in Israel. Y.P. acknowledges support by GTEP and for a Levi Eshkol scholarship from the Ministry of Science and Technology of Israel. A.R. acknowledges the support of the L. Shirley Tark Chair in Science.
Publisher Copyright:
© 2022 The Electrochemical Society (";ECS";). Published on behalf of ECS by IOP Publishing Limited. [DOI: 10.1149/1945-7111/ac63f7].
PY - 2022/4/1
Y1 - 2022/4/1
N2 - External quantum efficiency (EQE) of bismuth vanadate thin film photoanodes, measured in a pH 7 potassium phosphate buffer solution with sodium sulfite hole scavenger, was observed to substantially decrease when measured under white light bias (LB). While the EQE exhibited a fast initial decrease across its full spectral range, a ∼3.5 eV (350 nm) feature under front illumination conditions became disproportionally suppressed after being under LB (strongest when it is also incident on the front side of the sample) for several tens of minutes, in spite of this wavelength being outside the spectral range encompassed by the LB source. Applied potential does not have a strong effect on the qualitative behavior. From its different decay time, the wavelength-specific decrease of the 3.5 eV feature, and its responsible mechanism, is distinct from the initial, spectrally uniform decrease of EQE, which happens at a faster timescale and is similar for all illumination conditions. To more closely examine the suppression of the 3.5 eV feature, we compare calculated depth-dependent optical generation profiles and behaviors under different illumination conditions, which imply the involvement of in-gap states and long-lived states deeper into the conduction (or alternatively, valence) band. Possible mechanisms are discussed.
AB - External quantum efficiency (EQE) of bismuth vanadate thin film photoanodes, measured in a pH 7 potassium phosphate buffer solution with sodium sulfite hole scavenger, was observed to substantially decrease when measured under white light bias (LB). While the EQE exhibited a fast initial decrease across its full spectral range, a ∼3.5 eV (350 nm) feature under front illumination conditions became disproportionally suppressed after being under LB (strongest when it is also incident on the front side of the sample) for several tens of minutes, in spite of this wavelength being outside the spectral range encompassed by the LB source. Applied potential does not have a strong effect on the qualitative behavior. From its different decay time, the wavelength-specific decrease of the 3.5 eV feature, and its responsible mechanism, is distinct from the initial, spectrally uniform decrease of EQE, which happens at a faster timescale and is similar for all illumination conditions. To more closely examine the suppression of the 3.5 eV feature, we compare calculated depth-dependent optical generation profiles and behaviors under different illumination conditions, which imply the involvement of in-gap states and long-lived states deeper into the conduction (or alternatively, valence) band. Possible mechanisms are discussed.
UR - http://www.scopus.com/inward/record.url?scp=85129524700&partnerID=8YFLogxK
U2 - 10.1149/1945-7111/ac63f7
DO - 10.1149/1945-7111/ac63f7
M3 - Article
AN - SCOPUS:85129524700
VL - 169
JO - Journal of the Electrochemical Society
JF - Journal of the Electrochemical Society
SN - 0013-4651
IS - 4
M1 - 046513
ER -