Immobilization of photosystem I or II complexes on electrodes for preparation of photoenergy-conversion devices

Photosystems, PSI and PSII isolated from Thermosynechococcus elongatus were successfully immobilized on a TiO 2 nanostructured film for use in dye-sensitized biosolar cells (DSBCs). The photosystem complexes were also immobilized on an ITO electrode modified with 3-aminopropyltriethoxysilane by utilizing the interactions between the electrode and the surface of the PSI or PSII polypeptide. Illumination of the PSI and PSII complexes immobilized on the ITO electrode resulted in action spectra in the presence of methyl viologen, which corresponded to the absorption spectra of the complexes. Compared with the ITO electrode, PSI or PSII complexes assembled on the TiO 2 electrode had much higher energy-conversion efficiency in the presence of an iodide/triiodide redox system of an ionic-liquid-based electrolyte. This could have interesting applications in the development of DSBCs.