Towards Stable Solar Hydrogen Generation with Organic Photoelectrochemical Cells.

MARTA HARO; CLAUDIA SOLIS; GONZALO MOLINA; LUIS OTERO; JUAN BISQUERT; SIXTO JIMÉNEZ; ANTONIO GUERRERO

JOURNAL OF PHYSICAL CHEMISTRY C

AMER CHEMICAL SOC

Lugar: Washington; Año: 2015 vol. 119 p. 6488 - 6494

1932-7447

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 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 achievable photocurrent (~1 mAcm-2) and stability of the photocathode (stable hydrogen generation of 1.5 mol h-1cm-2 for more than 3 h).