1,720,993 research outputs found
Diphenylbithiophenes as active layers in organic memory cells: a theoretical and experimental study
No full textThiol Functionalized Diphenyl Bithiophene for Monomolecular Bistable Layers
No full textDiphenyl bithiophene derivatives (DPBTs), known for their electrical bistable behavior, have been used in bulk resistive memory cells. In this article, we present the design and synthesis of a ω-alkyl thiol functionalized 3,3′-diphenyl 2,2′-bithiophene; such functionalization confers the ability to anchor on a metal surface, which may be conveniently applied for the development of monomolecular bistable devices
Electrospun Polymer Fibers for Electronic Applications
Full text linkNano- and micro- fibers of conjugated polymer semiconductors are particularly interesting both for applications and for fundamental research. They allow an investigation into how electronic properties are influenced by size confinement and chain orientation within microstructures that are not readily accessible within thin films. Moreover, they open the way to many applications in organic electronics, optoelectronics and sensing. Electro-spinning, the technique subject of this review, is a simple method to effectively form and control conjugated polymer fibers. We provide the basics of the technique and its recent advancements for the formation of highly conducting and high mobility polymer fibers towards their adoption in electronic applications
Electronic transport regimes through an alkoxythiolated diphenyl-2,2′-bithiophene-based molecular junction diodes: Critical assessment of the thermal dependence
Full text linkThe detailed understanding of electronic transport through a single molecule or an ensemble of self-assembled molecules embedded between two metallic leads is still a matter of controversy. Multiple factors influence the charge transport in the molecular junction, with particular attention to be given to the band states of the electrodes, molecular orbital energies, bias potential and importantly molecule-electrode electronic coupling. Moreover it is not trivial to disentangle molecular contributions from other possible conduction pathways directly coupling the opposite electrodes. We here investigate the electronic transport properties of an ensemble molecular junction embedding an alkylthiol derivative of a diphenol substituted bithiophene (DPBT) by means of current vs. voltage and temperature dependent measurements. We explored different junction configurations using: micropores (Au//DPBT//Au and Au//DPBT-polymer conductor//Au) and conductive-atomic force microscopy (c-AFM). In all cases, we found a transition voltage VT of ∼0.35 V. The consistent presence of a similar VT in all the tested configurations is a strong, but not conclusive, indication of a molecular signature in the charge transport, which we assessed and confirmed by temperature dependent measurements. We found a transition from an incoherent resonant tunneling at low biases and close to room temperature, where transport is thermally activated with an activation energy of ∼85 meV, to a coherent tunneling at voltages higher than VT. Unlike many other molecular junctions reported in the literature, resonant conditions commonly attributed to a hopping transport regime can be found already at room temperature and very low biases for a molecule only ∼1.5 nm long. This paper is the first report to clearly show temperature activated transport through a short and not fully conjugated molecule. Moreover, we could clearly identify a regime at low temperatures and low bias where the transport mechanism is controlled by the thermal conductivity of the metal electrodes rather than the molecule. © The Royal Society of Chemistry 2015
Infiltration and Selective Interactions at the Interface in Polymer-Oxide Hybrid Solar Cells
No full textPositron annihilation spectroscopy was used to characterize polymer-based hybrid solar cells formed by poly(3-hexylthiophene) (P3HT) finely infiltrated in a porous TiO2 skeleton. A step-change improvement in the device performance is enabled by engineering the hybrid interface by the insertion of a proper molecular interlayer namely 4-mercaptopyridine (4-MP). In order to obtain depth-resolved data, positrons were implanted in the sample using a variable-energy positron beam. The characteristics of the partially filled nanoporous structures were evaluated in terms of the depth profile of the positronium yield and the S-parameter. A quantitative evaluation of the pore filling in the deep region is given from the analysis of Coincidence Doppler Broadening taken at fixed implantation energy. We note a remarkable difference in terms of the positronium yield when the 4-MP interlayer is introduced, which means a better covering of P3HT on the porous surface
n-Type Semiconducting Polymer Fibers
No full textDefect-free bicomponent fibers of poly{[N,N′-bis(2-octyl-dodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)}/poly(ethyleneoxide) P(NDI2OD-T2)/PEO are fabricated by means of electrospinning and rinsed with a selective solvent to afford pure P(NDI2OD-T2) while maintaining a fibrous morphology. The elongation strength applied on the spun jet by the high electrical field induces a preferential orientation of polymer chains. An electron mobility analogous to the best obtained with a thin film-based device is achieved in single fiber transistors, and the results are unaffected by the dielectric surface treatment
Thiophene-based material for non volatile organic memory devices: a combined experimental and theoretical study
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