title: Nanostructured oligo(p-phenylene vinylene)/silicate hybrid films: one-step fabrication and energy transfer studies.
abstract: Novel hybrid materials containing silicate and charged oligo(p-phenylene vinylene) (OPV) amphiphiles were fabricated in one step by spin casting using evaporation-induced self assembly. The conjugated segments were substituted with trimethylammonium bromide groups at both termini, and tetraethyl orthosilicate served as the silicate precursor. X-ray diffraction scans of the hybrid films revealed Bragg diffraction peaks with d-spacings of 2.76 and 1.37 nm, indicating the presence of order in the hybrid structure. Optical properties of the hybrid films were characterized by UV-vis absorption and fluorescence spectra, and molecular orientation was characterized by IR spectroscopy. A rhodamine B derivative containing a triethoxysilane group was covalently incorporated into the silicate network of the films during the sol-gel reaction. Relative to disordered polymer films with identical organic composition, the ordered hybrid films revealed significantly enhanced emission from rhodamine B and also fluorescence quenching from OPV segments. These results indicate that the ordered and nanostructured environment leads to highly efficient energy transfer among organic components in these hybrid films.
authors.affiliation: Department of Chemistry, Feinberg School of Medicine, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Keisuke
authors.initials: K
authors.lastname: Tajima
authors.forename: Liang-shi
authors.initials: LS
authors.lastname: Li
authors.forename: Samuel I
authors.initials: SI
authors.lastname: Stupp