Interface Engineering for Stable, High-Performance Photoanodes

Zhou, X. et al. Interface Engineering of the Photoelectrochemical Performance of Ni-Oxide-Coated n-Si Photoanodes by Atomic-Layer Deposition of Ultrathin Films of Cobalt Oxide. Energy & Environmental Science, DOI: 10.1039/C5EE01687H (2015).


Scientific Achievement

We demonstrated that interfacial transition-metal oxide layers provide a route to stable, high-performance photoanodes for oxygen evolution in contact with aqueous 1 M KOH.

 

Significance & impact

The successful interface-engineering strategy provides a route to stable, high-performance photoanodes without buried p-n homojunctions, potentially simplifying processing, reducing cost, and increasing materials options for stable photoanodes.

 

 

Top:  High-resolution transmission-electron microscope image of a cross-section of an n-Si/SiOx/CoOx/NiOx sample

Bottom:  Current-density vs. potential (J-E) behavior of protected n-Si photoanodes with (green) and without (blue) an interfacial CoOx layer under simulated AM 1.5G solar illumination in contact with 1.0 M KOH(aq).

  Adapted from Zhou, X. et al. Interface Engineering of the Photoelectrochemical Performance of Ni-Oxide-Coated n-Si Photoanodes by Atomic-Layer Deposition of Ultrathin Films of Cobalt Oxide. Energy & Environmental Science, DOI: 10.1039/C5EE01687H (2015) with permission of The Royal Society of Chemistry.

 

Adapted from Zhou, X. et al. Interface Engineering of the Photoelectrochemical Performance of Ni-Oxide-Coated n-Si Photoanodes by Atomic-Layer Deposition of Ultrathin Films of Cobalt Oxide. Energy & Environmental Science, DOI: 10.1039/C5EE01687H (2015) with permission of The Royal Society of Chemistry.

Research Details

  • Ni-oxide films formed by reactive sputtering provide a transparent, anti-reflective, conductive, chemically stable, inherently catalytic coating that stabilizes many efficient and technologically important photoandoes.
  • Significantly high open-circuit voltage (Voc) values for such stabilized systems have been obtained from electrodes formed by deposition of a NiOx coating onto a buried np+ homojunction.
  • n-Si/SiOx/CoOx/NiOx photoanodes in contact with 1 M KOH(aq) and under simulated 1-Sun illumination yielded photocurrent-onset potentials of ∼ −240 mV relative to formal potential for water oxidation (E0’(O2/H2O)) and current densities of ∼ 28 mA·cm−2at E0’(O2/H2O) and provided continuous, stable oxygen evolution for 1700 h.
  • Interfacia cobalt oxide layers potentially simplify the photoelectrod processing.

Contact: nslewis@caltech.edu 

 

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