TY - JOUR
T1 - Considerations for the Accurate Measurement of Incident Photon to Current Efficiency in Photoelectrochemical Cells
AU - Ellis, David S.
AU - Piekner, Yifat
AU - Grave, Daniel A.
AU - Schnell, Patrick
AU - Rothschild, Avner
N1 - Funding Information:
The research leading to these results has received funding from the PAT Center of Research Excellence supported by the Israel Science Foundation (grant no: 1867/17). The IPCE measurements were carried out at the Technion’s Photovoltaics Laboratory (HTRL), supported by the Russell Berrie Nanotechnology Institute (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. Part of the work was funded by the Volkswagen Foundation. DG and DE acknowledge support from the Center for Absorption in Science at the Ministry of Aliyah and Immigrant Absorption in Israel. YP acknowledges support by the Levi Eshkol scholarship from the Ministry of Science and Technology of Israel. AR acknowledges the support of the L. Shirley Tark Chair in Science.
Publisher Copyright:
Copyright © 2022 Ellis, Piekner, Grave, Schnell and Rothschild.
PY - 2022/1/5
Y1 - 2022/1/5
N2 - In this paper we review some of the considerations and potential sources of error when conducting Incident Photon to Current Efficiency (IPCE) measurements, with focus on photoelectrochemical (PEC) cells for water splitting. The PEC aspect introduces challenges for accurate measurements often not encountered in dry PV cells. These can include slow charge transfer dynamics and, depending on conditions (such as a white light bias, which is important for samples with non-linear response to light intensity), possible composition changes, mostly at the surface, that a sample may gradually undergo as a result of chemical interactions with the aqueous electrolyte. These can introduce often-overlooked dependencies related to the timing of the measurement, such as a slower measurement requirement in the case of slow charge transfer dynamics, to accurately capture the steady-state response of the system. Fluctuations of the probe beam can be particularly acute when a Xe lamp with monochromator is used, and longer scanning times also allow for appreciable changes in the sample environment, especially when the sample is under realistically strong white light bias. The IPCE measurement system and procedure need to be capable of providing accurate measurements under specific conditions, according to sample and operating requirements. To illustrate these issues, complications, and solution options, we present example measurements of hematite photoanodes, leading to the use of a motorized rotating mirror stage to solve the inherent fluctuation and drift-related problems. For an example of potential pitfalls in IPCE measurements of metastable samples, we present measurements of BiVO4 photoanodes, which had changing IPCE spectral shapes under white-light bias.
AB - In this paper we review some of the considerations and potential sources of error when conducting Incident Photon to Current Efficiency (IPCE) measurements, with focus on photoelectrochemical (PEC) cells for water splitting. The PEC aspect introduces challenges for accurate measurements often not encountered in dry PV cells. These can include slow charge transfer dynamics and, depending on conditions (such as a white light bias, which is important for samples with non-linear response to light intensity), possible composition changes, mostly at the surface, that a sample may gradually undergo as a result of chemical interactions with the aqueous electrolyte. These can introduce often-overlooked dependencies related to the timing of the measurement, such as a slower measurement requirement in the case of slow charge transfer dynamics, to accurately capture the steady-state response of the system. Fluctuations of the probe beam can be particularly acute when a Xe lamp with monochromator is used, and longer scanning times also allow for appreciable changes in the sample environment, especially when the sample is under realistically strong white light bias. The IPCE measurement system and procedure need to be capable of providing accurate measurements under specific conditions, according to sample and operating requirements. To illustrate these issues, complications, and solution options, we present example measurements of hematite photoanodes, leading to the use of a motorized rotating mirror stage to solve the inherent fluctuation and drift-related problems. For an example of potential pitfalls in IPCE measurements of metastable samples, we present measurements of BiVO4 photoanodes, which had changing IPCE spectral shapes under white-light bias.
KW - EQE
KW - IPCE
KW - device characterisation
KW - measurement technique
KW - photoelectrochemical
UR - http://www.scopus.com/inward/record.url?scp=85123055253&partnerID=8YFLogxK
U2 - 10.3389/fenrg.2021.726069
DO - 10.3389/fenrg.2021.726069
M3 - Article
AN - SCOPUS:85123055253
VL - 9
JO - Frontiers in Energy Research
JF - Frontiers in Energy Research
SN - 2296-598X
M1 - 726069
ER -