@article{da3dfbe3e54249dcb38100b5bbbcfc7b,
title = "Wasted photons: Photogeneration yield and charge carrier collection efficiency of hematite photoanodes for photoelectrochemical water splitting",
abstract = "Hematite (α-Fe2O3) is a leading photoanode candidate for photoelectrochemical water splitting. Despite extensive research efforts, the champion hematite photoanodes reported to date have achieved less than half of the maximal photocurrent predicted by its bandgap energy. Here we show that this underachievement arises, to a large extent, because of unproductive optical excitations that give rise to localized electronic transitions that do not generate electron-hole pairs. A comprehensive method for extraction of the photogeneration yield spectrum, the wavelength-dependent fraction of absorbed photons that generate electron-hole pairs, and the spatial charge carrier collection efficiency is presented, and applied for a thin (32 nm) film hematite photoanode. Its photogeneration yield is less than unity across the entire absorption range, limiting the maximal photocurrent that may be attained in an ideal hematite photoanode to about half of the theoretical limit predicted without accounting for this effect. This journal is ",
author = "Yifat Piekner and Ellis, {David S.} and Grave, {Daniel A.} and Anton Tsyganok and Avner Rothschild",
note = "Funding Information: The authors would like to acknowledge Dr Hen Dotan for early discussions on this subject, Dr Guy Ankonina for assisting on technical matters in the Technion{\textquoteright}s Photovoltaics Laboratory, Dr Cecile Saguy for advising with the AFM measurements, and Netta Gal for recording the SEM images. 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 EQE and optical measurements were carried out at the Technion{\textquoteright}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. Y. P. acknowledges support by the Grand Technion Energy Program (GTEP), and the Levi Eshkol scholarship from the Ministry of Science and Technology of Israel (Grant No. 3-14501). D. A. G. acknowledges support from the Center for Absorption in Science at the Ministry of Aliyah and Immigrant Absorption in Israel. A. R. acknowledges the support of the L. Shirley Tark Chair in Science. Publisher Copyright: {\textcopyright} The Royal Society of Chemistry.",
year = "2021",
month = aug,
day = "1",
doi = "10.1039/d1ee01772a",
language = "English",
volume = "14",
pages = "4584--4598",
journal = "Energy and Environmental Science",
issn = "1754-5692",
publisher = "Royal Society of Chemistry",
number = "8",
}
