Research
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
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.