Towards Stable Solar Hydrogen Generation using Organic Photoelectrochemical Devices
M. Haro, C. Solis, G. Molina, L. Otero, J. Bisquert, S. Gimenez, A. Guerrero J. Phys. Chem. C.119, 6488-6494
Organic photoactive materials are promising candidates for the generation of solar fuels in terms of efficiency and cost. However, their low stability in aqueous media constitutes a serious problem for technological deployment. Here we present organic photocathodes for the generation of hydrogen in aqueous media with outstanding stability. The device design relies on the use of water-resistant selective contacts, which protect a P3HT:PCBM photoactive layer. An insoluble cross-linked PEDOT:PSS hole-selective layer avoids delamination of the film, and an electron-selective TiOx layer in contact with the aqueous solution electrically communicates the organic layer with the hydrogen-evolving catalyst (Pt). We developed a novel method for the synthesis of the TiOx layer compatible with low-temperature conditions. Tuning the thickness of the TiOx/Pt layer leads to a trade-off between the achievable photocurrent (∼1 mAcm−2) and the stability of the photocathode (stable hydrogen generation of 1.5 μmol h−1 cm−2 for >3 h).
Organic photoactive materials are promising candidates for the generation of solar fuels in terms of efficiency and cost. However, their low stability in aqueous media constitutes a serious problem for technological deployment. Here we present organic photocathodes for the generation of hydrogen in aqueous media with outstanding stability. The device design relies on the use of water-resistant selective contacts, which protect a P3HT:PCBM photoactive layer. An insoluble cross-linked PEDOT:PSS hole-selective layer avoids delamination of the film, and an electron-selective TiOx layer in contact with the aqueous solution electrically communicates the organic layer with the hydrogen-evolving catalyst (Pt). We developed a novel method for the synthesis of the TiOx layer compatible with low-temperature conditions. Tuning the thickness of the TiOx/Pt layer leads to a trade-off between the achievable photocurrent (∼1 mAcm−2) and the stability of the photocathode (stable hydrogen generation of 1.5 μmol h−1 cm−2 for >3 h).