title: Photoinitiated [corrected] charge separation in a hybrid titanium dioxide metalloporphyrin peptide material.
abstract: In natural systems, electron flow is mediated by proteins that spatially organize donor and acceptor molecules with great precision. Achieving this guided, directional flow of information is a desirable feature in photovoltaic media. Here, we design self-assembled peptide materials that organize multiple electronic components capable of performing photoinduced charge separation. Two peptides, c16-AHL3K3-CO2H and c16-AHL3K9-CO2H, self-assemble into fibres and provide a scaffold capable of binding a metalloporphyrin via histidine axial ligation and mineralize titanium dioxide (TiO2) on the lysine-rich surface of the resulting fibrous structures. Electron paramagnetic resonance studies of this self-assembled material under continuous light excitation demonstrate charge separation induced by excitation of the metalloporphyrin and mediated by the peptide assembly structure. This approach to dye-sensitized semiconducting materials offers a means to spatially control the dye molecule with respect to the semiconducting material through careful, strategic peptide design.
authors.affiliation: Argonne National Laboratory, Center for Nanoscale Materials, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: H Christopher
authors.initials: HC
authors.lastname: Fry
authors.affiliation: Argonne National Laboratory, Center for Nanoscale Materials, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Yuzi
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Argonne National Laboratory, Center for Nanoscale Materials, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Nada M
authors.initials: NM
authors.lastname: Dimitrijevic
authors.affiliation: Argonne National Laboratory, Center for Nanoscale Materials, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: Tijana
authors.initials: T
authors.lastname: Rajh
mesh_terms: D004396:Coloring Agents; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D004583:Electrons; D006639:Histidine; D008239:Lysine; D008665:Metalloporphyrins / Q000737:chemistry*; D008958:Models, Molecular; D010455:Peptides / Q000737:chemistry*; D055668:Photochemical Processes; D014025:Titanium / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D008665:Metalloporphyrins; D010455:Peptides; C009495:titanium dioxide; D006639:Histidine; D014025:Titanium; D008239:Lysine