title: Molecular organization and effective energy transfer in iridium metallosurfactant-porphyrin assemblies embedded in Langmuir-Schaefer films.
abstract: Mixed Langmuir monolayers and Langmuir-Schaefer (LS) films containing the cationic metallosurfactant bis(2-phenylpyridine)(4,4'-diheptadecyl-2,2'-bipyridine)-iridium(III) chloride (Ir-complex) and the anionic tetrakis(4-sulfonatophenyl)porphyrin (TSPP) in 4:1 molar ratio have been successfully prepared by the co-spreading method at the air-water interface. The presence of both luminescent species at the interface, as well as the organization of the TSPP underneath the Ir-complex matrix in Langmuir and LS films, is inferred by surface techniques such as π-A isotherms, reflection spectroscopy, Brewster angle microscopy (BAM) and UV-visible absorption spectroscopy. A red-shift in the absorption band of the porphyrin under the compression of the mixed monolayer suggests the J-aggregation of the TSPP under the Ir-complex matrix. To date, this is the first report of Langmuir and/or LS films containing these two types of species together. Furthermore, the intermolecular energy transfer between Ir-complex and TSPP molecules in solution and in transferred mixed films is investigated through steady-state fluorescence and lifetime measurements. These results indicate that effective intermolecular energy transfer occurs from the Ir-complex to the TSPP molecules in LS films. The influence of the spatial proximity of donor and acceptor molecules has been studied by the insertion of lipid interlayers among them.
authors.affiliation: Department of Physical Chemistry and Applied Thermodynamics, University of Cordoba, Campus de Rabanales, Edificio Marie Curie, Cordoba, E-14014, Spain.
authors.forename: Cristina
authors.initials: C
authors.lastname: Roldán-Carmona
authors.forename: Antonio M
authors.initials: AM
authors.lastname: González-Delgado
authors.forename: Andrés
authors.initials: A
authors.lastname: Guerrero-Martínez
authors.forename: Luisa
authors.initials: L
authors.lastname: De Cola
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Giner-Casares
authors.forename: Marta
authors.initials: M
authors.lastname: Pérez-Morales
authors.forename: María T
authors.initials: MT
authors.lastname: Martín-Romero
authors.forename: Luis
authors.initials: L
authors.lastname: Camacho