Details

Autor(en) / Beteiligte

• Zhao, Yixin
• Swierk, John R
• Megiatto, Jackson D
• Sherman, Benjamin
• Youngblood, W. Justin
• Qin, Dongdong
• Lentz, Deanna M
• Moore, Ana L
• Moore, Thomas A
• Gust, Devens
• Mallouk, Thomas E

Titel

Improving the efficiency of water splitting in dye-sensitized solar cells by using a biomimetic electron transfer mediator

Ist Teil von

• Proceedings of the National Academy of Sciences - PNAS, 2012-09, Vol.109 (39), p.15612-15616

Ort / Verlag

United States: National Academy of Sciences

Erscheinungsjahr

2012

Quelle

MEDLINE

Beschreibungen/Notizen

• Photoelectrochemical water splitting directly converts solar energy to chemical energy stored in hydrogen, a high energy density fuel. Although water splitting using semiconductor photoelectrodes has been studied for more than 40 years, it has only recently been demonstrated using dye-sensitized electrodes. The quantum yield for water splitting in these dye-based systems has, so far, been very low because the charge recombination reaction is faster than the catalytic four-electron oxidation of water to oxygen. We show here that the quantum yield is more than doubled by incorporating an electron transfer mediator that is mimetic of the tyrosine-histidine mediator in Photosystem II. The mediator molecule is covalently bound to the water oxidation catalyst, a colloidal iridium oxide particle, and is coadsorbed onto a porous titanium dioxide electrode with a Ruthenium polypyridyl sensitizer. As in the natural photosynthetic system, this molecule mediates electron transfer between a relatively slow metal oxide catalyst that oxidizes water on the millisecond timescale and a dye molecule that is oxidized in a fast light-induced electron transfer reaction. The presence of the mediator molecule in the system results in photoelectrochemical water splitting with an internal quantum efficiency of approximately 2.3% using blue light.