Engineered Electron‐Transfer Chain in Photosystem 1 Based Photocathodes Outperforms Electron‐Transfer Rates in Natural Photosynthesis. Issue 35 (25th July 2014)

• Record Type: Journal Article
• Authors: Kothe, Tim; Pöller, Sascha; Zhao, Fangyuan; Fortgang, Philippe; Rögner, Matthias; Schuhmann, Wolfgang; Plumeré, Nicolas
• Is Part Of: Chemistry. Volume 20:Issue 35(2014)
• Page Start: 11029
• Page End: 11034
• Publication Date: 2014-07-25
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201402585
• Languages: English
• ISSNs: 0947-6539

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>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 O₂ 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.</p> </abstract>