F. Mengoni

[2.2]Paracyclophanes incorporated within poly(3-butylthiophene): synthesis and photoelectrical properties

The synthesis and photoelectrical properties of [2.2]paracyclophanes, containing conjugated acetylenic triple bonds in the linear side-chain, are described. These compounds were incorporated as an electroactive component within a conductive polymer, i.e. poly(3-butylthiophene). The blend showed a photoelectrical response higher than that of the neat polymer. Surprisingly, it was found that the application of an electric bias during the preparation of the blend led to an increase in the photocurrent.

Enhancement of Photoelectrical Properties in Polymer Nanocomposites Containing Modified Single-walled Carbon Nanotubes by Conducting Dendrimer

We report the photoinduced conductivity changes measured on a system composed of single-wall carbon nanotubes (SWNTs) modified by a semiconducting poly(amidoamine) dendrimer (PAMAMC) characterized by highly aromatic end groups. Under illumination hole injection into SWNTs prevails over the photoinjection of electrons from PAMAMC to SWNT holes, and film photoconductivity is observed. This system was incorporated as an electroactive component within a conducting polymer [poly(3-octylthiophene)], providing improvements in the photoelectrical properties of the composite. Such supramolecular structures consisting of dendrimer-functionalized carbon nanotubes provide the means for an approach toward the preparation of photoactive materials of high current interest.

Chemical gating and photoconductivity of CF4 plasma-functionalized single-walled carbon nanotubes with adsorbed butylamine

In this work we have developed a method to covalently attach butylamine molecules to the sidewall of single-walled carbon nanotubes (SWNTs) starting from fluorinated SWNTs (F-SWNTs) obtained by CF4 plasma treatment at room temperature. Scanning tunneling microscopy images demonstrate that after the sidewall fluorination of SWNTs some bundles with a lower number of single tubes are present. The subsequent amine functionalization of the tubes has been demonstrated by infrared spectroscopy and thermogravimetric measurements. The chemical adsorption of butylamine molecules on F-SWNTs has been also investigated by electrical transport measurements in thin-film transistor geometry. The electrical conductance of SWNTs decreases after adsorption of butylamine. The amine groups in the molecule are electron donating and the observed photoconductivity of amino-functionalized F-SWNTs is presumably due to the injection of electrons from amine groups to SWNTs.

Electrodeposition of polyfluorene on a carbon nanotube electrode

Electrophoretically deposited single-walled carbon nanotube (SWCNT) films on a transparent conducting surface are used as electrodes for the electrodeposition of a π-conjugated polymer formed by the oxidative coupling of fluorene units. This method provides a uniform coverage of the conducting surface with respect to SWCNTs chemically assembled on a gold substrate. Electron microscopy reveals the formation of a polymer–SWCNT nanostructure which imparts distinct electrical properties from those of the polymer electrodeposited on the neat electrode. By combining the attractive properties of SWCNTs and polyfluorene, these nanocomposites open up new opportunities to achieve electrical contacts in nano- to micro-devices.