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Item type:Publication, Access status: without files , Synthesis of an organic conductive porous material using starch aerogels as template for chronic invasive electrodesWe report the development of an organic conducting mesoporous material, as coat for invasive electrodes, by a novel methodology based on the use of starch aerogel as template. The poly(3,4-ethylenedioxythiophene) (PEDOT) aerogel was synthesized by polymerization of 3,4-ethylenedioxythiophene within a saturated starch aerogel with iron (III) p-toluenesulfonate (oxidizing agent) and subsequent removal of the polysaccharide template, followed by supercritical CO2 drying. The chemical structure and oxidation state of the resulting material were studied by Raman spectroscopy. The morphology and surface properties of the obtained nanoporous material were investigated by scanning electron microscopy (SEM), micro computed tomography (μCT) and nitrogen adsorption-desorption techniques. The composition and thermal behaviour were evaluated by energy dispersive spectroscopy (EDS) and thermogravimetric analysis (TGA) respectively. A preliminary biocompatibility test verified the non-cytotoxic effects of the PEDOT aerogel. The large surface area and wide pore size distribution of the PEDOT conductive aerogel, along with its electrical properties, enable it to be used as extracellular matrix scaffold for biomedical applications.Publicationtype: Journal ArticleScopus© Citations 41 15 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , In vitro biocompatibility study and electrical properties of the PEDOT, PEDOT collagen coat, PEDOT nanotubes and PEDOT aerogels for neural electrodesThe aim of this study is to evaluate the cytotoxicity of Poly(3, 4-ethylenedioxythiophene) (PEDOT), PEDOT-collagen and PEDOT nanostructured coatings for neural electrodes. Incorporation of cell growth factors and the structuration of supporting material are two strategies to improve cell adhesion and biocompatibility in order to produce better and more specific neural implants. PEDOT coat, PEDOT-collagen coat, PEDOT nanotubes and PEDOT aerogel were tested for biocompability using the standard ISO 10993-5. PEDOT and PEDOT-Collagen coats were deposited via galvanostatic electropolymerization from a NaPSS micellar dispersion. In addition PEDOT nanotubes were obtained by hard polycarbonate template and PEDOT aerogels were chemically produced through a soft starch template. PEDOT samples were studied for biocompatibility, characterized by LCRmeter and Scanning electron microscopy (SEM). Biocompatibility test verified the absence of cytotoxic effects in all the PEDOT samples.Publicationtype: Journal Article104 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Effect of experimental factors on the properties of PEDOT-NaPSS galvanostatically deposited from an aqueous micellar media for invasive electrodes(IEEE, 2012-12); ; ; Poly(3,4-ethylenedioxythiophene) (PEDOT) coat for invasive electrodes has been generated considerable interest in terms of electrical properties and biocompatibility. Adequate formulations and methodology are necessary to deposit polymer reproducibly on macro and micro-electrodes. Electrochemical properties of PEDOT as interface material were assessed with respect to different experimental factors. PEDOT/NaPSS was polymerized from a sodium polystyrenesulfonate (NaPSS) dispersion. The dispersion was characterized by cyclic voltammetry and its critical micellar concentration (CMC) value is reported, according to our best knowledge, for the first time for PEDOT deposition. The polymer obtained was studied using Raman spectroscopy, impedance and cyclic voltammetry measurement. PEDOT-NaPSS coat shows high charge injection (Qinj), low interfacial impedance (Z) and superficial chemical stability (Raman). This study provides a simple, constant and reproducible framework to coat invasive electrodes.Publicationtype: Conference Paper10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Hole trap related hysteresis in pentacene field-effect transistors(American Institute of Physics (AIP), 2008-11-07); ; ; ; We have investigated hysteresis in pentacene-based field-effect transistors with SiO2 as gate dielectric. A clear hysteresis behavior in transfer and output characteristics is reported. Measurements show that the observed hysteresis is due to hole trapping in the pentacene film. Long time constants of the trapping/detrapping mechanism are demonstrated through transient measurements. An initialization routine to be performed prior to measurements is proposed to enable reproducible and reliable measurements on pentacene transistors. © 2008 American Institute of Physics.Publicationtype: Journal Article4 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , A physical-based PSPICE compact model for poly(3-hexylthiophene) organic field-effect transistorsA PSPICE model for organic thin-film transistors (OFETs) employing poly(3-hexylthiophene-2,5-diyl) (P3HT) is derived. This model is based on the standard MOSFET Berkeley Short-channel IGFET Model equations, where the voltage dependences of the charge carrier mobility and the bulk conductivity are modeled by additional voltage-controlled current sources. The model requires only five additional parameters, which can be extracted from the output characteristics of the device. The model equations have been verified by device simulations, and the simulation results have been compared with measurements of P3HT OFETs.Publicationtype: Journal Article10 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Gate insulators and interface effects in organic thin-film transistors(Elsevier, 2008-02); ; ; ; This paper presents a detailed characterization of different thermosetting polymers to be used as gate dielectrics in organic thin-film transistors. Selected materials yield smooth films with good insulation properties and offer attractive processing conditions. Bottom-gate transistors were prepared using these dielectrics and compared to hybrid transistors with surface-treated SiO2 as the dielectric. Gate bias induced leakage and solvent effects were investigated by preparing metal/insulator/semiconductor devices. Poly(3-hexylthiophene) (P3HT) transistors with organic dielectrics exhibited higher channel conductivity and lower mobility values with respect to P3HT-hybrid transistors and pentacene transistors. The importance of dielectric/semiconductor interface was discussed by comparing the performances of pentacene and P3HT transistors produced on different dielectrics.Publicationtype: Journal Article13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Spin-cast composite gate insulation for low driving voltages and memory effect in organic field-effect transistors(American Institute of Physics (AIP), 2007-02-19); ; ; ; The authors report on a solution-processed composite film based on poly(vinylidene fluoride/trifluoroethylene) copolymer and barium titanate (BT) nanopowder, to be used as ferroelectric high- κ gate insulation in organic field-effect transistors (OFETs). Flexible films of up to 50 vol % BT powder content are produced by preparing homogeneous dispersion of the powder in the polymer solutions. The films exhibited high specific volume resistivities combined with dielectric constants of up to 51.5 at 1 kHz. Low-voltage OFETs with ferroelectric hysteresis and good memory retention properties were demonstrated by using the composite films. © 2007 American Institute of Physics.Publicationtype: Journal Article7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Bottom gate organic field effect transistors made by laser structuring(Elsevier, 2006-12); ; This paper presents a process to manufacture all-polymer field effect transistors in a bottom gate configuration where all electrodes - including the gate electrode - are patterned using an excimer laser in combination with a scanning unit. This technique yields channel lengths of 10 μm between the source and the drain electrodes. Being a combination of a scanning and a single shot patterning process it is a promising candidate for an industrial process with a resolution of 10 μm and an operational throughput of at least 6 cm2/s.Publicationtype: Journal Article7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Wavelength-selective organic field-effect phototransistors based on dye-doped poly-3-hexylthiophene(American Institute of Physics (AIP), 2006-09-08); ; ; ; The authors present a strategy to manufacture wavelength-selective field-effect phototransistors by employing dye-doped poly-3-hexylthiophene (P3HT) as a semiconducting layer. The dye doping of the semiconductor P3HT was achieved by blending organic molecules - coumarin 6, oxazine 1, and nile red - into the conjugated organic polymer. Illuminating these transistors with monochromatic light in the range of 400-700 nm resulted in varying conductivities for certain wavelengths in dependence on the particular dye. This effect is attributed to the photogeneration of excitons on the dye molecules, which are subsequently transferred to the conjugated polymer. © 2006 American Institute of Physics.Publicationtype: Journal Article2 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Static model for organic field-effect transistors including both gate-voltage-dependent mobility and depletion effect(American Institute of Physics (AIP), 2006-06-05); ; ; 4