Porous translucent electrodes enhance current generation from photosynthetic biofilms.


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Authors
Bombelli, Paolo 
Howe, Christopher J 
Abstract

Some photosynthetically active bacteria transfer electrons across their membranes, generating electrical photocurrents in biofilms. Devices harvesting solar energy by this mechanism are currently limited by the charge transfer to the electrode. Here, we report the enhancement of bioelectrochemical photocurrent harvesting using electrodes with porosities on the nanometre and micrometre length scale. For the cyanobacteria Nostoc punctiforme and Synechocystis sp. PCC6803 on structured indium-tin-oxide electrodes, an increase in current generation by two orders of magnitude is observed compared to a non-porous electrode. In addition, the photo response is substantially faster compared to non-porous anodes. Electrodes with large enough mesopores for the cells to inhabit show only a small advantage over purely nanoporous electrode morphologies, suggesting the prevalence of a redox shuttle mechanism in the electron transfer from the bacteria to the electrode over a direct conduction mechanism. Our results highlight the importance of electrode nanoporosity in the design of electrochemical bio-interfaces.

Description
Keywords
Biofilms, Electric Conductivity, Electricity, Electrochemical Techniques, Electrodes, Electron Transport, Light, Nostoc, Oxidation-Reduction, Photosynthesis, Photosystem I Protein Complex, Photosystem II Protein Complex, Porosity, Shewanella, Synechocystis, Tin Compounds
Journal Title
Nat Commun
Conference Name
Journal ISSN
2041-1723
2041-1723
Volume Title
9
Publisher
Springer Science and Business Media LLC
Sponsorship
Leverhulme Trust (RPG-2015-393)