Photocurrent generation by direct electron transfer using photosynthetic reaction centres
| Autor: | E T Lagally, Seyed M. Mirvakili, J. T. Beatty, Eric Ouellet, Arash Takshi, John D. W. Madden, Daniel Jun, Rafael G. Saer, B Iranpour, Ali Mahmoudzadeh |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
chemistry.chemical_classification
Photocurrent Photosynthetic reaction centre Materials science Electron donor Electron Electron acceptor Condensed Matter Physics Redox Atomic and Molecular Physics and Optics Electron transfer chemistry.chemical_compound chemistry Mechanics of Materials Chemical physics Signal Processing General Materials Science Electrical and Electronic Engineering Atomic physics Quantum tunnelling Civil and Structural Engineering |
| Zdroj: | Smart Materials and Structures. 20:094019 |
| ISSN: | 1361-665X 0964-1726 |
| DOI: | 10.1088/0964-1726/20/9/094019 |
| Popis: | Photosynthetic reaction centres (RCs) convert light into separated charges with nearly perfect quantum efficiency, and have been used to generate photocurrent. Previous work has shown that electron tunnelling rates between redox centres in proteins depend exponentially on the tunnelling distance. In this work the RC from Rhodobacter sphaeroides was genetically modified with the aim of achieving the shortest tunnelling distances yet demonstrated between the RC's electron-accepting P site and underlying graphite and gold electrodes, and between the electron donor Q site and graphite electrodes. Opposite charges are carried to counter electrodes using mobile mediators, as in dye-sensitised solar cells. Native RCs are bound to graphite surfaces through N-(1-pyrene)iodoacetamide. Although the linker's length is only 4 A, the electron transfer pathway between the Q electron donor site on the RC and the electrode surface is still too large for current to be significant. A mutant version with the electron acceptor P side close to the graphite surface produced currents of 15 nA cm−2 upon illumination. Direct binding of RCs to a gold surface is shown, resulting in currents of 5 nA cm−2. In both cases the current was unaffected by mediator concentration but increased with illumination, suggesting that direct electron transfer was achieved. The engineering of an RC to achieve direct electron transfer will help with long term efforts to demonstrate RC-based photovoltaic devices. |
| Databáze: | OpenAIRE |
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