Engineered electron-transfer chain in photosystem 1 based photocathodes outperforms electron-transfer rates in natural photosynthesis

Tim Kothe, Sascha Pöller, Fangyuan Zhao, Philippe Fortgang, Matthias Rögner, Wolfgang Schuhmann, Nicolas Plumeré

Research output: Contribution to journalArticlepeer-review

113 Scopus citations

Abstract

Photosystem 1 (PS1) triggers the most energetic light-induced charge-separation step in nature and the in vivo electron-transfer rates approach 50 e- s-1 PS1-1. Photoelectrochemical devices based on this building block have to date underperformed with respect to their semiconductor counterparts or to natural photosynthesis in terms of electron-transfer rates. We present a rational design of a redox hydrogel film to contact PS1 to an electrode for photocurrent generation. We exploit the pH-dependent properties of a poly(vinyl)imidazole Os(bispyridine)2Cl polymer to tune the redox hydrogel film for maximum electron-transfer rates under optimal conditions for PS1 activity. The PS1-containing redox hydrogel film displays electron-transfer rates of up to 335±14 e- s-1 PS1-1, which considerably exceeds the rates observed in natural photosynthesis or in other semiartificial systems. Under O 2 supersaturation, photocurrents of 322±19 μA cm -2 were achieved. The photocurrents are only limited by mass transport of the terminal electron acceptor (O2). This implies that even higher electron-transfer rates may be achieved with PS1-based systems in general.

Original languageEnglish
Pages (from-to)11029-11034
Number of pages6
JournalChemistry - A European Journal
Volume20
Issue number35
DOIs
StatePublished - 25 Aug 2014
Externally publishedYes

Keywords

  • bio-electrochemistry
  • electron transfer
  • pH response
  • photovoltaics
  • redox hydrogel

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