Overcoming Phase-Purity Challenges in Complex Metal Oxide Photoelectrodes: A Case Study of CuBi2O4

Ronen Gottesman*, Igal Levine, Markus Schleuning, Rowshanak Irani, Daniel Abou-Ras, Thomas Dittrich, Dennis Friedrich, Roel van de Krol*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The widespread application of solar-water-splitting for energy conversion depends on the progress of photoelectrodes that uphold stringent criteria from photoabsorber materials. After investigating almost all possible elemental and binary semiconductors, the search must be expanded to complex materials. Yet, high structural control of these materials will become more challenging with an increasing number of elements. Complex metal-oxides offer unique advantages as photoabsorbers. However, practical fabrication conditions when using glass-based transparent conductive-substrates with low thermal-stability impedes the use of common synthesis routes of high-quality metal-oxide thin-film photoelectrodes. Nevertheless, rapid thermal processing (RTP) enables heating at higher temperatures than the thermal stabilities of the substrates, circumventing this bottleneck. Reported here is an approach to overcome phase-purity challenges in complex metal-oxides, showing the importance of attaining a single-phase multinary compound by exploring large growth parameter spaces, achieved by employing a combinatorial approach to study CuBi2O4, a prime candidate photoabsorber. Pure CuBi2O4 photoelectrodes are synthesized after studying the relationship between the crystal-structures, synthesis conditions, RTP, and properties over a range of thicknesses. Single-phase photoelectrodes exhibit higher fill-factors, photoconversion efficiencies, longer carrier lifetimes, and increased stability than nonpure photoelectrodes. These findings show the impact of combinatorial approaches alongside radiative heating techniques toward discovering highly efficient multinary photoabsorbers.

Original languageAmerican English
Article number2003474
JournalAdvanced Energy Materials
Issue number11
StatePublished - 18 Mar 2021
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2021 The Authors. Advanced Energy Materials published by Wiley-VCH GmbH


  • CuBiO
  • complex metal oxides
  • pulsed laser deposition
  • radiative heating
  • rapid thermal processing
  • solar water splitting


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