Considerations for the Accurate Measurement of Incident Photon to Current Efficiency in Photoelectrochemical Cells

Frontiers in Energy Research

David S. Ellis¹  Avner Rothschild¹  Daniel A. Grave²  Patrick Schnell³  Yifat Piekner⁴ 

[1] Department of Materials Science and Engineering, Technion–Israel Institute of Technology, Haifa, Israel;Department of Materials Science and Engineering, Technion–Israel Institute of Technology, Haifa, Israel;Department of Materials Engineering and Ilse Katz Institute for Nanoscale Science and Technology, Ben Gurion University of the Negev, Be’er Sheva, Israel;Institute for Solar Fuels, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin, Germany;Institute of Chemistry, Technische Universität Berlin, Berlin, Germany;The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion–Israel Institute of Technology, Haifa, Israel;

关键词: IPCE;    EQE;    photoelectrochemical;    device characterisation;    measurement technique;   

DOI  :  10.3389/fenrg.2021.726069

来源: Frontiers

【 摘 要 】

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.

【 授权许可】

CC BY