Best Practices in PEC Water Splitting: How to Reliably Measure Solar-to-Hydrogen Efficiency of Photoelectrodes

Olivia Alley, Keenan Wyatt, Myles Steiner, Guiji Liu, Tobias Kistler, Guosong Zeng, David Larson, Jason Cooper, James Young, Todd Deutsch, Francesca Toma

Research output: Contribution to journalArticlepeer-review

11 Scopus Citations


Photoelectrochemical (PEC) water splitting, which utilizes sunlight and water to produce hydrogen fuel, is potentially one of the most sustainable routes to clean energy. One challenge to success is that, to date, similar materials and devices measured in different labs or by different operators lead to quantitatively different results, due to the lack of accepted standard operating procedures and established protocols for PEC efficiency testing. With the aim of disseminating good practices within the PEC community, we provide a vetted protocol that describes how to prepare integrated components and accurately measure their solar-to-hydrogen (STH) efficiency (ηSTH). This protocol provides details on electrode fabrication, ηSTH test device assembly, light source calibration, hydrogen evolution measurement, and initial material qualification by photocurrent measurements under monochromatic and broadband illumination. Common pitfalls in translating experimental results from any lab to an accurate STH efficiency under an AM1.5G reference spectrum are discussed. A III–V tandem photocathode is used to exemplify the process, though with small modifications, the protocol can be applied to photoanodes as well. Dissemination of PEC best practices will help those approaching the field and provide guidance for comparing the results obtained at different lab sites by different groups.

Original languageAmerican English
Article number884364
Number of pages24
JournalFrontiers in Energy Research
StatePublished - 2022

Bibliographical note

Publisher Copyright:
Copyright © 2022 Alley, Wyatt, Steiner, Liu, Kistler, Zeng, Larson, Cooper, Young, Deutsch and Toma.

NREL Publication Number

  • NREL/JA-5900-82320


  • faradaic efficiency
  • III–V tandem solar cells
  • incident photon-to-current efficiency
  • light source calibration
  • photoelectrochemical
  • solar-to-hydrogen conversion efficiency
  • water splitting


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