Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Highly efficient water splitting by a dual-absorber tandem cell


Photoelectrochemical water-splitting devices, which use solar energy to convert water into hydrogen and oxygen, have been investigated for decades. Multijunction designs are most efficient, as they can absorb enough solar energy and provide sufficient free energy for water cleavage. However, a balance exists between device complexity, cost and efficiency. Water splitters fabricated using triple-junction amorphous silicon1,2 or IIIV3 semiconductors have demonstrated reasonable efficiencies, but at high cost and high device complexity. Simpler approaches using oxide-based semiconductors in a dual-absorber tandem approach4,5 have reported solar-to-hydrogen (STH) conversion efficiencies only up to 0.3% (ref. 4). Here, we present a device based on an oxide photoanode and a dye-sensitized solar cell, which performs unassisted water splitting with an efficiency of up to 3.1% STH. The design relies on carefully selected redox mediators for the dye-sensitized solar cell6,7 and surface passivation techniques8 and catalysts9 for the oxide-based photoanodes.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: General schemes and energy diagrams for a photoanode/DSC D4 tandem cell.
Figure 2: Spectral response and J–V characteristics.
Figure 3: Faradaic efficiency measurement of a tandem cell.


  1. Rocheleau, R. & Miller, E. High-efficiency photoelectrochemical hydrogen production using multijunction amorphous silicon photoelectrodes. Energy Fuels 12, 3–10 (1998).

    Article  Google Scholar 

  2. Reece, S. Y. et al. Wireless solar water splitting using silicon-based semiconductors and earth-abundant catalysts. Science 334, 645–648 (2011).

    Article  ADS  Google Scholar 

  3. Khaselev, O. & Turner, J. A monolithic photovoltaic–photoelectrochemical device for hydrogen production via water splitting. Science 280, 425–427 (1998).

    Article  ADS  Google Scholar 

  4. Mor, G. K. et al. p-Type Cu–Ti–O nanotube arrays and their use in self-biased heterojunction photoelectrochemical diodes for hydrogen generation. Nano Lett. 8, 1906–1911 (2008).

    Article  ADS  Google Scholar 

  5. Ida, S. et al. Preparation of p-type CaFe2O4 photocathodes for producing hydrogen from water. J. Am. Chem. Soc. 132, 17343–17345 (2010).

    Article  Google Scholar 

  6. Yum, J-H. et al. A cobalt complex redox shuttle for dye-sensitized solar cells with high open-circuit potentials. Nature Commun. 3, 631 (2012).

    Article  ADS  Google Scholar 

  7. Yella, A. et al. Porphyrin-sensitized solar cells with cobalt (II/III)-based redox electrolyte exceed 12 percent efficiency. Science 334, 629–634 (2011).

    Article  ADS  Google Scholar 

  8. Le Formal, F. et al. Passivating surface states on water splitting hematite photoanodes with alumina overlayers. Chem. Sci. 2, 737–743 (2011).

    Article  Google Scholar 

  9. Tilley, S. D., Cornuz, M., Sivula, K. & Graetzel, M. Light-induced water splitting with hematite: improved nanostructure and iridium oxide catalysis. Angew. Chem. Int. Ed. 49, 6405–6408 (2010).

    Article  Google Scholar 

  10. Walter, M. G. et al. Solar water splitting cells. Chem. Rev. 110, 6446–6473 (2010).

    Article  Google Scholar 

  11. Weber, M. & Dignam, M. Efficiency of splitting water with semiconducting photoelectrodes. J. Electrochem. Soc. 131, 1258–1265 (1984).

    Article  ADS  Google Scholar 

  12. Gao, X., Kocha, S. & Frank, A. Photoelectrochemical decomposition of water using modified monolithic tandem cells. Int. J. Hydrogen Energ. 24, 319–325 (1999).

    Article  Google Scholar 

  13. Kelly, N. & Gibson, T. Design and characterization of a robust photoelectrochemical device to generate hydrogen using solar water splitting. Int. J. Hydrogen Energ. 31, 1658–1673 (2006).

    Article  Google Scholar 

  14. Graetzel, M. & Augustyński, J. Tandem cell for water cleavage by visible light. US patent 6,936,143 (2005).

  15. Arakawa, H. et al. Solar hydrogen production by tandem cell system composed of metal oxide semiconductor film photoelectrode and dye-sensitized solar cell. Proc. SPIE 6650, 665003 (2007).

    Article  Google Scholar 

  16. Brillet, J. et al. Examining architectures of photoanode–photovoltaic tandem cells for solar water splitting. J. Mater. Res. 25, 17–24 (2010).

    Article  ADS  Google Scholar 

  17. Pendlebury, S. R. et al. Dynamics of photogenerated holes in nanocrystalline α-Fe2O3 electrodes for water oxidation probed by transient absorption spectroscopy. Chem. Commun. 47, 716–718 (2011).

    Article  Google Scholar 

  18. Solarska, R., Jurczakowski, R. & Augustyński, J. A highly stable, efficient visible-light driven water photoelectrolysis system using a nanocrystalline WO3 photoanode and a methane sulfonic acid electrolyte. Nanoscale 4, 1553–1556 (2012).

    Article  ADS  Google Scholar 

  19. Kanan, M. W. & Nocera, D. G. In situ formation of an oxygen-evolving catalyst in neutral water containing phosphate and Co2+. Science 321, 1072–1075 (2008).

    Article  ADS  Google Scholar 

  20. Zhong, D. K. & Gamelin, D. R. Photoelectrochemical water oxidation by cobalt catalyst (‘Co–Pi’)/α-Fe2O3 composite photoanodes: oxygen evolution and resolution of a kinetic bottleneck. J. Am. Chem. Soc. 132, 4202–4207 (2010).

    Article  Google Scholar 

  21. Hisatomi, T. et al. Cathodic shift in onset potential of solar oxygen evolution on hematite by 13-group oxide overlayers. Energy Environ. Sci. 4, 2512–2515 (2011).

    Article  Google Scholar 

  22. Hisatomi, T. et al. A Ga2O3 underlayer as an isomorphic template for ultrathin hematite films toward efficient photoelectrochemical water splitting. Faraday Discuss. 155, 223–232 (2012).

    Article  ADS  Google Scholar 

  23. Mi, Q., Zhanaidarova, A., Brunschwig, B. S., Gray, H. B. & Lewis, N. S. A quantitative assessment of the competition between water and anion oxidation at WO3 photoanodes in acidic aqueous electrolytes. Energy Environ. Sci. 5, 5694–5700 (2012).

    Article  Google Scholar 

  24. Wang, P. et al. A stable quasi-solid-state dye-sensitized solar cell with an amphiphilic ruthenium sensitizer and polymer gel electrolyte. Nature Mater. 2, 402–407 (2003).

    Article  ADS  Google Scholar 

  25. Brillet, J., Graetzel, M. & Sivula, K. Decoupling feature size and functionality in solution-processed, porous hematite electrodes for solar water splitting. Nano Lett. 10, 4155–4160 (2010).

    Article  ADS  Google Scholar 

  26. Thimsen, E., Le Formal, F., Graetzel, M. & Warren, S. C. Influence of plasmonic Au nanoparticles on the photoactivity of Fe2O3 electrodes for water splitting. Nano Lett. 11, 35–43 (2011).

    Article  ADS  Google Scholar 

  27. Santato, C., Odziemkowski, M., Ulmann, M. & Augustyński, J. Crystallographically oriented mesoporous WO3 films: synthesis, characterization, and applications. J. Am. Chem. Soc. 123, 10639–10649 (2001).

    Article  Google Scholar 

  28. Tsao, H. N. et al. Cyclopentadithiophene bridged donor–acceptor dyes achieve high power conversion efficiencies in dye-sensitized solar cells based on the tris-cobalt bipyridine redox couple. ChemSusChem 4, 591–594 (2011).

    Article  Google Scholar 

  29. Ahmad, S., Yum, J. H., Xianxi, Z., Graetzel, M. & Butt, H. Dye-sensitized solar cells based on poly (3,4-ethylenedioxythiophene) counter electrode derived from ionic liquids. J. Mater. Chem. 20, 1654–1658 (2010).

    Article  Google Scholar 

  30. Ito, S. et al. Fabrication of thin film dye sensitized solar cells with solar to electric power conversion efficiency over 10%. Thin Solid Films 14, 4613–4619 (2008).

    Article  ADS  Google Scholar 

Download references


J.B. and T.H. acknowledge funding from the Swiss Federal Office of Energy (PecHouse2, SI/50090-02). J-H.Y. acknowledges support from the Korea Foundation for International Cooperation in Science and Technology through the Global Research Lab. M.C. acknowledges Toyota Motor Corp. for financial support. The authors thank P. Comte and F. Kessler for assistance in preparing the TiO2 paste and the cobalt complex. The authors also thank NEC corporation (Japan) for providing the Y123 dye.

Author information

Authors and Affiliations



J.B., M.G. and K.S. conceived the experiment. K.S. directed the experimental work and J.B. performed the experiments. J-H.Y. prepared the DSC. M.C. prepared the haematite photoanodes. R.S. and J.A. prepared the WO3 photoanodes. T.H. measured the Faradaic efficiency. J.B. and K.S. wrote the manuscript.

Corresponding author

Correspondence to Kevin Sivula.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 554 kb)

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Brillet, J., Yum, JH., Cornuz, M. et al. Highly efficient water splitting by a dual-absorber tandem cell. Nature Photon 6, 824–828 (2012).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing