Photovoltaic cells based on sequentially adsorbed multilayers of conjugated poly(p-phenylene ethynylene)s and a water-soluble fullerene derivative.

We describe the layer-by-layer (LBL) fabrication of multilayer films and photovoltaic cells using poly(phenylene ethynylene)-based anionic conjugated polyelectrolytes as electron donors and water-soluble cationic fullerene C60 derivatives as acceptors. LBL film deposition was found to be linearly related to the number of bilayers as monitored by UV-vis absorption. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) of the multilayer films revealed an aggregated but relatively uniform morphology devoid of any long-range phase separation.

Luminescent core-shell photonic crystals from poly(phenylene ethynylene) coated silica spheres.

We describe the preparation and characterization of a photonic crystal filled with a luminescent conjugated polyelectrolyte, sulfonated poly(phenylene ethynylene). The conjugated polymer was coated onto the nanospheres by the layer-by-layer method and assembled directly into a fluorescent opal structure avoiding the defects associated with post-filling schemes. These structures exhibit strong angle-dependent luminescent properties.

Luminescence quenching of a phosphorescent conjugated polyelectrolyte.

The photophysical and luminescence quenching properties of a platinum(II) acetylide-based conjugated polyelectrolyte, Pt-p, which features carboxylic acid solubilizing groups are reported. The Pt-acetylide polymer is water soluble, and it exhibits phosphorescence from a triplet pi,pi exciton based on the conjugated backbone. The phosphorescence from Pt-p is quenched by viologens with different charges (MV(+), MV(2+), and MV(4+)), and in each case the quenching is dominated by a dynamic (diffusional) mechanism.

Amplified quenching of a conjugated polyelectrolyte by cyanine dyes.

The conjugated polyelectrolyte PPESO3 features a poly(phenylene ethynylene) backbone substituted with anionic 3-sulfonatopropyloxy groups. PPESO3 is quenched very efficiently (KSV > 10(6) M(-1)) by cationic energy transfer quenchers in an amplified quenching process. In the present investigation, steady-state and picosecond time-resolved fluorescence spectroscopy are used to examine amplified quenching of PPESO3 by a series of cyanine dyes via singlet-singlet energy transfer.

Amplified fluorescence sensing of protease activity with conjugated polyelectrolytes.

Fluorescent conjugated polyelectrolytes with pendant ionic sulfonate and carboxylate groups are used to sense protease activity. Inclusion of the fluorescent conjugated polyelectrolyte into the assay scheme leads to amplification of the sensory response. The sensing mechanism relies on an electrostatic interaction between the conjugated polyelectrolyte and a peptide substrate that is labeled with a fluorescence quencher.

Saccharide Detection Based on the Amplified Fluorescence Quenching of a Water-Soluble Poly(phenylene ethynylene) by a Boronic Acid Functionalized Benzyl Viologen Derivative.

The amplified quenching of an anionic conjugated polymer, sulfonated poly(phenylene ethynylene) (PPE-SO ), by a cationic quencher comprising a boronic acid functionalized benzyl viologen (-BV), has been used to optically detect sugars. In the absence of sugar, a strong polymer/quencher interaction leads to superlinear quenching. In the presence of sugar at pH 7.

Photophysics, aggregation and amplified quenching of a water-soluble poly(phenylene ethynylene).

The fluorescence, absorption and fluorescence quenching properties of an anionic poly(phenylene ethynylene) are investigated in H2O and MeOH solutions.