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We present a joint experimental and theoretical study of the structural and charge-transport properties of a liquid-crystalline alpha,omega-disubstituted oligothiophene derivative for application ill organic field-effect transistors. The structural properties of the crystalline and smectic phases are investigated by atomic force microscopy, X-ray reflectometry, and X-ray diffraction. To complement these data, molecular mechanics calculations together with the simulation of X-ray diffraction spectra were performed to determine the relative positions of the molecules in the unit cell. The electrical characteristics of field-effect transistors based oil the oligothiophene derivative were measured and compared in the crystalline and smectic phases. Although the silanation of the SiO2 gate dielectric promoted a marked improvement in the char-c-carrier mobilities in the crystalline Phase, the expected suppression of grain boundaries ill the liquid-crystalline phase was not unambiguously evidenced. The experimental results were further complemented by a detailed theoretical analysis of the electronic couplings governing the charge-transport properties oil the molecular scale.

Yet,manyoftheseapplicationsarecurrently builtatthe macroscale rather than at the nanoscale.Standard micro- and nanoscale-machining technology isless adapted to ECPs and, generally, is in its infancy formolecularmaterialscomparedtoSi-basedtechnology.Amajoreffort in progressing towards precise engineering of molecularmaterials has been thoroughly devoted to several emergingunconventional techniques. In particular, ECPs have beenpatterned via high-throughput lithography

We present results obtained by applying the nanorubbing process to improve the electrical performance of regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) thin films. Essentially, we use a scanning atomic force microscope tip to induce a controlled deformation on the surface consisting of parallel grooves with a period imposed by the scanning parameters. The optical characterization of the rubbed zones highlights an orientation of P3HT chains along the scanning direction. When the nanorubbing process is orienting the polymer chains within the channel of a field-effect transistor, we observe that the charge carrier mobility increases (decreases) when the tip scans parallel (perpendicular) to the source-drain axis. This difference likely stems from the polymer chains orientation induced by the alignment process. (C) 2008 Elsevier B.V. All rights reserved.

Putting in practice the recycling projects of the damaging secondary powder products as dust, scale (mixture of oxides � fabrication defect appearing at rolling) or sand resulted in steel industry effluents removal, needs to be characterized from physical, chemical and technological point of view. This paper aims to realise a new classification of the damaging material and new definitions for their characteristics. The proposed groups are: producing characteristics, impact characteristics, removal characteristics and recycling valorisation characteristics. To underline the technological importance of the used characteristics as work instruments has been programmed experimental researches regarding the diminishing of the recycling of the dust and the sand obtained after the electric arc furnace gas removal and scale from rolling. The characteristics of recycling valorisation have been assessed: chemical composition and Zn assimilation ratio in the steel, the efficiency in liquid steel, the degree of replacing the scrap iron and the recycling chemical composition.

We report on a newly developed technology for the nanoscale processing of the conducting polyaniline (PANI) with an unprecedented areal patterning order and density control exceeding 0.25 teradot/inch2. A simple two-step process is put forward to hierarchically build a large variety of functional PANI nanostructures on virtually any type of flexible or rigid substrates. Using template confinement, through Pt catalyzed electroless growth, highly-ordered arrays of distinct PANI nanowires are produced. Complex three-dimensional (3D) structural control is achieved through a direct pattern transfer using a novel type of resist- and dose-modulated 3D electron beam lithography. The method is scalable and provides a generic approach for nanopatterning surfaces with functional polymers. Aspects of the nanoscale PANI growth mechanism are discussed and the highly controllable, sub-picogram scale fabrication is emphasized. Simple schemes for single PANI nanowire fabrication, processing and device integration are presented.

Unconventional nanofabrication is attractive for organic electronics because of its potential impact in manufacturing low-cost electronics starting from soluble precursors that can be processed and patterned via a sustainable technology. So far, the major endeavor aimed at the development of organicbased devices has been through the design of new materials, novel synthetic procedures and purification methods, optimized conditions for thin film growth, and original methods for nanofabrication. In particular, a strong effort was devoted to the technological control of organic semiconductors in transistors. Yet, only a limited number of studies have focused on new approaches for low cost fabrication of electrodes and their integration with the organic materials. Successful examples of unconventional electrode manufacturing include stencil printing of Au nanoparticles, inkjet printing, Ag electroless plating followed by microcontact patterning, lamination, microtransfer printing of Ag nanoparticles, metal transfer printing, and soft lithography. Although inkjet printing is probably the most straightforward example of an additive process where both the electrodes and the active layers can be realized on the same platform, the fabrication of the electrodes and the active layers often relies on different processes, specifications, and platforms. Precisely, standard microfabrication approaches consisting of photolithography and/or electron-beam lithography followed by vacuum metallization are generally used for the source and drain definition, while wet methods (spin-coating, layer-by

We demonstrate that arrays of nanowires of conjugated polymers can be easily produced by a simple embossing protocol, compatible with very large scale integration technology. The embossing process is shown to have the supplementary virtue to increase the internal degree of order of the nanowires, significantly enhancing their performance. This is applied to the fabrication of nanowire-based devices consisting of a liquid crystalline light-emitting polymer, of a liquid crystalline semiconducting polymer, and of an amorphous conducting polymer, illustrating the versatility and wide applicability of the method.

We have optimized dihexylquaterthiophene-based thin film transistors for low-power consumption and have studied their characteristics for potential introduction in analog circuits. Bottom-gate devices with Pd source and drain electrodes have been fabricated by employing different gate dielectrics. Transistors with very thin (< 10 nm) silicon oxynitride dielectrics display subthreshold swing values below 100 mV/decade, cutoff frequencies approaching the kilohertz range and intrinsic gain around 45 dB, suggesting that they are promising candidates for low-power analog integration.

We report on the microstructure of 2(3)-9(10)-16(17)-23(24)-tetra(2-decyltetradecyloxy)- phthalocyanine/peryleneoleylamine (PcH2/PTCDI) blends. Thin films, to be used as active layers in organic photovoltaic cells, were prepared by spin coating and spin casting of dilute toluene solutions on indium tin oxide (ITO) substrates. The morphology of the thin films has been studied using Tapping Mode (TM) atomic force microscopy (AFM), whereas Scanning Electron Microscopy (SEM) was used to reveal the various top electrode morphologies, inherent to the different film processing conditions.