Alessandro Geri

Solar cells based on poly(3-alkyl)thiophenes and [60]fullerene: a comparative study

Photovoltaic cells made, at ambient conditions, from blends of regioregular poly(3-alkylthiophenes) and soluble fullerene derivatives are compared. It is shown that the cell performance is affected by the length of the donor side-chain, as it occurs in devices based on pure polythiophenes. The highest value of power conversion efficiency (0.84%) were obtained by using poly(3-hexylthiophene) and a fullerene concentration of 33-40% by weight. We anticipate a significant further improvement in power conversion efficiency upon a mild thermal treatment of the cells.

A solid-state electrochromic device based on complementary polypyrrole/polythiophene derivatives and an elastomeric electrolyte

A device was assembled using optically transparent glass electrodes and combining two complementary electrochromic polymeric materials, poly(4,4′-dipentoxy-2,2′-bithiophene) and poly(N,N′-dimethyl-2,2′-bipyrrole). As electrolyte we used an ionically conductive polymer; poly(epichlorohydrin-co-ethylene oxide) containing a lithium salt. The optical contrast in the visible/near infrared region, stability to repeated redox cycles and electrochromic efficiency are reported and discussed.

Hall mobility in poly(4,4′-dipentoxy-2,2′bithiophene) as a function of the doping level

We report a systematic study of the Hall mobility and the carrier concentration of a conjugated polymer [poly(4,4′-dipentoxy-2,2′bithiophene)] as a function of the electrochemical doping level, over a wide range of the carrier concentration (from ∼1015 to ∼1019 cm−3). Very high values were obtained for the carrier mobility (from 102 to 10−1 cm2 V−1 s−1), when compared with those reported in the literature for organic materials. Furthermore, an inverse relationship between mobility and carrier concentration was found.

Electropolymerization of Heterocycles on Poly(Vinylch1oride) Coated Electrodes

Abstract : Processing is one of the most important problems connected with the technological use of the conducting polymers. An interesting method to obtain an utilizable material is the electrochemical polymerization of a suitable monomer on an electrode coated by an easily processable polymer film. This method was applied to several heterocycles with different molecular weights, such as dithienopyrrole (DTPY), N-methyl-10,10-dimethylphenazasiline (SIN) and [1]benzothieno[3,2-blindole (TNI), polymerized on poly(vinylchloride) (PVC). The results of this research are described and discussed.

Composite of poly(Dithienopyrrole) and poly(Vinylchloride) obtained by the electrode coating method

Composite films obtained by the electrochemical polymerization of dithienopyrrole onto poly(vinylchloride) coated platinum or ITO electrodes were prepared and studied in this work. Results obtained by thermal analysis and microscopy show the composite nature of the material. The electrochromic properties were studied by dynamic spectroelectrochemistry and resemble those of the pure poly(dithienopyrrole) polymer.