Bi-Containing n-FeWO4 Thin Films Provide the Largest Photovoltage and Highest Stability for a Sub-2 eV Band Gap Photoanode

Zhou, L., Shinde, A., Suram, S., Stein, H., Bauers, S., Zakutayev, A., DuChene, J., Liu, G., Peterson, E., Neaton, J., Gregoire, J. Bi-containing n-FeWO4 Thin Films Provide the Largest Photovoltage and Highest Stability for a sub-2 eV Band Gap Photoanode. ACS Energy Letters, DOI: 10.1021/acsenergylett.8b01514 (2018).


Scientific Achievement

Through combinatorial exploration of composition space, highly absorbing films containing the FeWO4 phase were discovered, exhibiting a sub-2 eV
band gap, operational stability, and high photovoltage

Significance & impact

These 3 key characteristics are essential for applications in solar-fuels generators, making FeWO4-based films the most promising photoanodes to date

Research Details

  • FeWO4 is typically p-type, but formation of an oxide coating during annealing limits
    O incorporation and enables n-type doping.

  • The film is passivated by WO3 in acid and by Fe2O3 in base, enabling a wide operational pH range

  • Increasing photovoltage has been challenging for metal oxides; the turn on potential below 0.4 V vs. RHE is best yet for <2 eV gap OD Cu catalysts have selective active sites for C-C coupled products: ethylene, ethanol/acetate, 1-propanol

Contact: gregoire@caltech.edu

Read More Research Highlights

Reprinted from Zhou, L., Shinde, A., Suram, S., Stein, H., Bauers, S., Zakutayev, A., DuChene, J., Liu, G., Peterson, E., Neaton, J., Gregoire, J. Bi-containing n-FeWO4 Thin Films Provide the Largest Photovoltage and Highest Stability for a sub-2 eV Band Gap Photoanode. ACS Energy Letters,  DOI: 10.1021/acsenergylett.8b01514  (2018).   Obtaining the high absorption FeWO4 phase requires exploration of synthesis and processing.  Due to self-passivation in acid and base, stable operation is obtained over a wide pH range, and including 5% Bi in the FeWO4 film provides excellent photovoltage.

Reprinted from Zhou, L., Shinde, A., Suram, S., Stein, H., Bauers, S., Zakutayev, A., DuChene, J., Liu, G., Peterson, E., Neaton, J., Gregoire, J. Bi-containing n-FeWO4 Thin Films Provide the Largest Photovoltage and Highest Stability for a sub-2 eV Band Gap Photoanode. ACS Energy Letters, DOI: 10.1021/acsenergylett.8b01514 (2018).

Obtaining the high absorption FeWO4 phase requires exploration of synthesis and processing. Due to self-passivation in acid and base, stable operation is obtained over a wide pH range, and including 5% Bi in the FeWO4 film provides excellent photovoltage.