Photosynthesis is a sustainable process that converts light energy into chemical energy. substantial research efforts are directed towards the application of the photosynthetic reaction centres, photosystems I and II, as active components for the light-induced generation of electrical power or fuel products. nonetheless, no integrated photo-bioelectrochemical device that produces electrical power, upon irradiation of an aqueous solution that includes two inter-connected electrodes is known. Here we report the assembly of photobiofuel cells that generate electricity upon irradiation of biomaterial-functionalized electrodes in aqueous solutions. The cells are composed of electrically contacted photosystem II-functionalized photoanodes and an electrically wired bilirubin oxidase/carbon nanotubes-modified cathode. Illumination of the photoanodes yields the oxidation of water to o 2 and the transfer of electrons through the external circuit to the cathode, where o 2 is re-reduced to water.

The photocurrents generated by a monolayer consisting of a CdS nanoparticles/acetylcholine esterase hybrid system associated with an electrode are controlled by the enzyme inhibitors.

Photochemical detection of a nucleic acid was achieved by means of a DNA‐cross‐linked CdS nanoparticle array attached to an electrode (see schematic diagram). The array was constructed from the target DNA (blue) and CdS nanoparticles bearing oligonucleotides complementary to its 3′‐ (green) and 5′‐ends (red). The photocurrent generated on irradiation of the array increases with increasing concentration of the target.

Photosensitizer/electron acceptor molecular cross-linked Au-nanoparticle arrays are assembled on indium-doped tin oxide (ITO) electrodes by a layer-by-layer deposition process. A Ru(II)-tris-(2,2′-bipyridine)cyclobis(paraquat-p-phenylene) catenane (1) or Zn(II)-protoporphyrin IX-bis(N-methyl-N′-undecanoate-4,4′bipyridinium) (2) are used as molecular cross-linkers for the generation of Au-nanoparticle (13 ( 1 nm) arrays of a controlled number of layers. The Au-nanoparticle arrays are characterized by absorbance spectroscopy and by electrochemical means. The electrodes functionalized with 1-or 2-cross-linked Au-nanoparticle arrays are used in photoelectrochemical experiments. The resulting action spectra of the photocurrents follow the absorbance spectra of the respective chromophores. Mechanistic studies indicate that the photocurrents originate from intramolecular electron-transfer quenching of the photoexcited state of the photosensitizer by the electron acceptor units, leading to the formation of intermediate redox species. The oxidized photoproduct oxidizes the sacrificial electron donor, Na 2 EDTA, whereas the reduced bipyridinium radical cations transfer the electrons to the bulk electrode support.