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Electronic Materials (electronic + material)
Kinds of Electronic Materials Selected AbstractsThin Films: Self-Assembled Heteroepitaxial Oxide Nanocomposite Thin Film Structures: Designing Interface-Induced Functionality in Electronic Materials (Adv. Funct.ADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Mater. Achieving self-assembling/self-organizing systems is the holy grail of nanotechnology, as presented in the Feature Article by J. L. MacManus-Driscoll on page 2035. Multifunctionality or enhanced functionality can emerge as a result of self-assembly of two oxides in nano-composite films. Checkerboards, ordered nanochains, nanorods, or random nanoparticle structures are all possible structures and they influence the resulting properties in different ways. It is now possible to predict the nanocomposite structure that will form from a given starting composition. [source] Self-Assembled Heteroepitaxial Oxide Nanocomposite Thin Film Structures: Designing Interface-Induced Functionality in Electronic MaterialsADVANCED FUNCTIONAL MATERIALS, Issue 13 2010Judith L. MacManus-Driscoll Abstract Achieving self-assembling/self-organizing systems is the holy grail of nanotechnology. Spontaneous organization is not unique to the physical sciences since nature has been producing such systems for millions of years. In biological systems global patterns emerge from numerous interactions among lower-level components of the system. The same is true for physical systems. In this review, the self-assembly mechanisms of oxide nanocomposite films, as well as the advantageous functionalities that arise from such ordered structures, are explored. [source] Dibenzotetrathiafulvalene Bisimides: New Building Blocks for Organic Electronic Materials**,ADVANCED MATERIALS, Issue 19 2007K. Gao A new class of organic species, dibenzotetrathiafulvalene bisimides (see figure), were designed and synthesized by using a facile and general synthetic strategy. The new bisimides possess a diverse library of derivatives with various functionalities at the imide rings, and they show promise for use in a range of organic electronic applications. [source] Trends in the use of digital libraries by scientists in 2000-2005: A case study of finelibPROCEEDINGS OF THE AMERICAN SOCIETY FOR INFORMATION SCIENCE & TECHNOLOGY (ELECTRONIC), Issue 1 2006Pertti Vakkari This study explores the trends in the use of electronic material and digital libraries by university faculty between the years 2000 and 2005. The data consist of nationwide web-based surveys of the end-users of FinELib, Finnish Electronic Library, at all Finnish universities. Although material provision has grown tremendously and consequently the use of electronic literature and of FinELib, the clients were polarizing into frequent and infrequent users. Perceived availability of the material provided was a major factor influencing this polarization. Availability was significantly stronger predictor of the use than users' discipline. It seems that availability underlies the disciplinary variation in the use of digital libraries. [source] A novel route to perovskite lead zirconate titanate from glycolate precursors via the sol,gel processAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 2 2008N. Tangboriboon Abstract A perovskite lead zirconate titanate was synthesized by the sol-gel process, using lead glycolate, sodium tris(glycozirconate) and titanium glycolate as the starting precursors. For the mole ratio Pb:Zr:Ti of 1:0.5:0.5 [Pb(Zr0.5Ti0.5)O3], TGA-DSC thermal analysis indicated that the percentage of ceramic yield was 55.8, close to the calculated chemical composition value of 49.5. The exothermic peak occurred at 268 °C below the theoretical Curie temperature of 400 °C. The pyrolysis of Pb(Zr0.5Ti0.5)O3 of the perovskite phase was investigated in terms of calcination temperature and time. The structure obtained was of the tetragonal form when calcined at temperatures below 400 °C; it transformed to the tetragonal and the cubic forms of the perovskite phase on calcination above the Curie temperature, as verified by X-ray data. The lead zirconate titanate synthesized and calcined at 400 °C for 1 h had the highest dielectric constant, the highest electrical conductivity and the dielectric loss tangent of 10 190, 0.803 × 10,3 (,.m),1 and 1.513 at 1000 Hz, respectively. The lead zirconate titanate powder synthesized has potential applications as an electronic material. Copyright © 2008 John Wiley & Sons, Ltd. [source] 3,9-Bis(dicyanomethylene)-2,4,8,10-tetrathiaspiro[5.5]undecaneACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2001Zheng-Rong Zhou The title compound, 2,2,-(2,4,8,10-tetrathiaspiro[5.5]undecane-3,9-diylidene)bis(propanedinitrile), C13H8N4S4, has been designed and synthesized for use as a potential new organic molecular electronic material. The spiro-annulated structure has twofold symmetry and is formed by two equal push,pull ethylene units, with the cycloalkylthio groups as electron donors and the cyano groups as electron acceptors. The intermolecular S,N non-bonded separation within a layer in the lattice is 3.296,(6),Å, indicating a strong intermolecular interaction between the cyano groups and the S atoms, while the S atoms in two neighbouring molecules have a shortest S,S contact of 3.449,(3),Å. In addition, attractive C,H,N and C,H,S interactions bridge adjacent molecules either within a layer or between layers. In short, these four types of intermolecular interactions combine to form an extended three-dimensional network in the lattice, resulting in a highly ordered array of molecular packing. [source] Simple and Efficient Generation of White Light Emission From Organophosphorus Building BlocksADVANCED FUNCTIONAL MATERIALS, Issue 22 2009Carlos Romero-Nieto Abstract This paper describes a structure,property study using two dithieno[3,2- b;2,,3,- d]phosphole building blocks for the generation of white light emission and the incorporation of these units in a single polystyrene material. The emission of one of the light-emitting organophosphorus building blocks can efficiently be switched from orange to green by simple protonation of the amino functional groups that are part of the , -conjugated scaffold. The resulting three components (blue, green, and orange) exhibit photophysical properties that allow for an efficient fluorescence resonance energy transfer (FRET) in the mixture/polymer and provide intense white fluorescence upon excitation of the blue component; the fluorescence is close to pure white in solution and similar to the emission of an incandescent light bulb in the thin film. The results nicely illustrate the intriguing features that can be obtained by exclusively using organophosphorus-based organic electronic materials. [source] Detailed Characterization of Contact Resistance, Gate-Bias-Dependent Field-Effect Mobility, and Short-Channel Effects with Microscale Elastomeric Single-Crystal Field-Effect TransistorsADVANCED FUNCTIONAL MATERIALS, Issue 5 2009Colin Reese Abstract The organic field-effect transistor (OFET) has proven itself invaluable as both the fundamental element in organic circuits and the primary tool for the characterization of novel organic electronic materials. Crucial to the success of the OFET in each of these venues is a working understanding of the device physics that manifest themselves in the form of electrical characteristics. As commercial applications shift to smaller device dimensions and structure/property relationships become more refined, the understanding of these phenomena become increasingly critical. Here, we employ high-performance, elastomeric, photolithographically patterned single-crystal field-effect transistors as tools for the characterization of short-channel effects and bias-dependent parasitic contact resistance and field-effect mobility. Redundant characterization of devices at multiple channel lengths under a single crystal allow the morphology-free analysis of these effects, which is carried out in the context of a device model previously reported. The data show remarkable consistency with our model, yielding fresh insight into each of these phenomena, as well as confirming the utility of our FET design. [source] Chemical and Physical Sensing by Organic Field-Effect Transistors and Related DevicesADVANCED MATERIALS, Issue 34 2010Takao Someya Abstract Organic semiconductor films are susceptible to noncovalent interactions, trapping and doping, photoexcitation, and dimensional deformation. While these effects can be detrimental to the performance of conventional circuits, they can be harnessed, especially in field-effect architectures, to detect chemical and physical stimuli. This Review summarizes recent advances in the use of organic electronic materials for the detection of environmental chemicals, pressure, and light. The material features that are responsible for the transduction of the input signals to electronic information are discussed in detail. [source] Stretchable, Curvilinear Electronics Based on Inorganic MaterialsADVANCED MATERIALS, Issue 19 2010Dae-Hyeong Kim Abstract All commercial forms of electronic/optoelectronic technologies use planar, rigid substrates. Device possibilities that exploit bio-inspired designs or require intimate integration with the human body demand curvilinear shapes and/or elastic responses to large strain deformations. This article reviews progress in research designed to accomplish these outcomes with established, high-performance inorganic electronic materials and modest modifications to conventional, planar processing techniques. We outline the most well developed strategies and illustrate their use in demonstrator devices that exploit unique combinations of shape, mechanical properties and electronic performance. We conclude with an outlook on the challenges and opportunities for this emerging area of materials science and engineering. [source] Solution Processing of Chalcogenide Semiconductors via Dimensional ReductionADVANCED MATERIALS, Issue 31 2009David B. Mitzi Abstract The quest to develop thin-film solution processing approaches that offer low-cost and preferably low-temperature deposition, while simultaneously providing quality semiconductor characteristics, has become an important thrust within the materials community. While inorganic compounds offer the potential for outstanding electronic properties relative to organic systems, the very nature of these materials rendering them good electronic materials,namely strong covalent bonding,also leads to poor solubility. This review presents a "dimensional reduction" approach to improving the solubility of metal chalcogenide semiconductors, which generally involves breaking the extended framework up into discrete metal chalcogenide anions separated by small and volatile cationic species. The resulting soluble precursor may be solution-processed into thin-film form and thermally decomposed to yield the desired semiconductor. Several applications of this principle to the solution deposition of high-performance active layers for transistors (channel mobility >10,cm2 V,1 s,1), solar cells (power conversion efficiency of as high as 12%), and fundamental materials study will be presented using hydrazine as the deposition solvent. [source] Orthogonal Patterning of PEDOT:PSS for Organic Electronics using Hydrofluoroether SolventsADVANCED MATERIALS, Issue 22 2009Priscilla G. Taylor By employing benign process solvents and specially tailored photopolymers, organic electronic materials can be lithographically patterned. Furthermore, because the process is acid stable, this is an ideal candidate for patterning acidic PEDOT:PSS, an important material for organic electronics. Fabrication of a multilayer OTFT demonstrates the potential of this orthogonal patterning process. [source] Scanning Probe Microscopy: Electrical Scanning Probe Microscopy on Active Organic Electronic Devices (Adv. Mater.ADVANCED MATERIALS, Issue 1 20091/2009) The inside cover, drawn by Irene Wang, illustrates that electrical atomic force microscopy techniques can play an integral part in the research and development of organic electronic materials. On p. 19 Pingree, Reid, and Ginger highlight the use of scanning probe microscopy techniques in examining heterogeneities, defects, and various transport properties including injection, trapping, and generation/recombination in organic lightemitting diodes, thin-film transistors, and solar cells. [source] Theoretical studies on the electronic and optical properties of two new alternating fluorene/carbazole copolymersJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 10 2005Li Yang Abstract Poly(fluorene)-type materials are widely used in polymer-based emitting devices. During operation there appears, however, an additional emission peak at around 2.3 eV, leading to both a color instability and reduced efficiency. The incorporation of the carbazole units has been proven to efficiently suppress the keto defect emission. In this contribution, we apply quantum-chemical techniques to investigate two series of alternating fluorene/carbazole oligomers and copolymers poly[2,7-(N-(2-methyl)-carbazole)- co - alt -2,7-m(9,9-dimethylfluorene)], namely, PFmCz (m = 1,2) and gain a detailed understanding of the influence of carbazole units on the electronic and optical properties of fluorene derivatives. The electronic properties of the neutral molecules, HOMO-LUMO gaps (,H-L), in addition to the positive and negative ions, are studied using B3LYP functional. The lowest excitation energies (Egs) and the maximal absorption wavelength ,abs of PFmCz (m = 1,2) are studied, employing the time-dependent density functional theory (TD-DFT). The properties of the two copolymers, such as ,H-L, Eg, IPs, and EAs were obtained by extrapolating those of the oligomers to the inverse chain length equal to zero (1/n = 0). The outcomes showed that the carbazole unit is a good electron-donating moiety for electronic materials, and the incorporation of carbazole into the polyfluorene (PF) backbone resulted in a broadened energy gap and a blue shift of both the absorption and photoluminescence emission peaks. Most importantly, the HOMO energies of PF1Cz and PF2Cz are both a higher average (0.4 eV) than polyfluorene (PF), which directly results in the decreasing of IPs of about 0.2 eV more than PF, indicating that the carbazole units have significantly improved the hole injection properties of the copolymers. In addition, the energy gap tends to broaden and the absorption and emission peaks are gradually blue-shifted to shorter wavelengths with an increase in the carbazole content in the copolymers. This is due to the interruption of the longer conjugation length of the backbone in the (F1Cz)n series. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 969,979, 2005 [source] Printed plastic electronics and paperlike displaysJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 20 2002John A. Rogers Abstract Plastic electronic materials and high-resolution printing methods may be important technologies for new classes of consumer electronic devices that are lightweight, mechanically flexible and bendable, and that can cover large areas at low cost. This article summarizes some of our recent work in this area. It focuses on the materials and patterning techniques that we used to produce plastic active-matrix backplane circuits for a type of paperlike display. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3327,3334, 2002 [source] Synchrotron X-ray topography of electronic materialsJOURNAL OF SYNCHROTRON RADIATION, Issue 3 2002T. Tuomi Large-area transmission, transmission section, large-area back-reflection, back-reflection section and grazing-incidence topography are the geometries used when recording high-resolution X-ray diffraction images with synchrotron radiation from a bending magnet, a wiggler or an undulator of an electron or a positron storage ring. Defect contrast can be kinematical, dynamical or orientational even in the topographs recorded on the same film at the same time. In this review article limited to static topography experiments, examples of defect studies on electronic materials cover the range from voids and precipitates in almost perfect float-zone and Czochralski silicon, dislocations in gallium arsenide grown by the liquid-encapsulated Czochralski technique, the vapour-pressure controlled Czochralski technique and the vertical-gradient freeze technique, stacking faults and micropipes in silicon carbide to misfit dislocations in epitaxic heterostructures. It is shown how synchrotron X-ray topographs of epitaxic laterally overgrown gallium arsenide layer structures are successfully explained by orientational contrast. [source] UV laser modification and selective ion-beam etching of amorphous vanadium pentoxide thin filmsPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 7 2009Alexander Cheremisin Abstract We present the results on excimer laser modification and patterning of amorphous vanadium pentoxide films. Wet positive resist-type and Ar ion-beam negative resist-type etching techniques were employed to develop UV-modified films. V2O5 films were found to possess sufficient resistivity compared to standard electronic materials thus to be promising masks for sub-micron lithography. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Theoretical design of bioinspired macromolecular electrets based on anthranilamide derivativesBIOTECHNOLOGY PROGRESS, Issue 4 2009M. K. Ashraf Abstract Polypeptide helices possess considerable intrinsic dipole moments oriented along their axes. While for proline helices the dipoles originate solely from the ordered orientation of the amide bonds, for 310, and ,-helices the polarization resultant from the formation of hydrogen-bond network further increases the magnitude of the macromolecular dipoles. The enormous electric-field gradients, generated by the dipoles of ,-helices (which amount to about 5 D per residue with 0.15 nm residue increments along the helix), play a crucial role in the selectivity and the transport properties of ion channels. The demonstration of dipole-induced rectification of vectorial charge transfer mediated by ,-helices has opened a range of possibilities for applications of these macromolecules in molecular and biomolecular electronics. These biopolymers, however, possess relatively large bandgaps. As an alternative, we examined a series of synthetic macromolecules, aromatic oligo- ortho -amides, which form extended structures with amide bonds in ordered orientation, supported by a hydrogen-bond network. Unlike their biomolecular counterparts, the extended ,-conjugation of these macromolecules will produce bandgaps significantly smaller than the polypeptide bandgaps. Using ab initio density functional theory calculations, we modeled anthranilamide derivatives that are representative oligo- ortho -amide conjugates. Our calculations, indeed, showed intrinsic dipole moments oriented along the polymer axes and increasing with the increase in the length of the oligomers. Each anthranilamide residue contributed about 3 D to the vectorial macromolecular dipole. When we added electron donating (diethylamine) and electron withdrawing (nitro and trifluoromethyl) groups for n- and p-doping, respectively, we observed that: (1) proper positioning of the electron donating and withdrawing groups further polarized the aromatic residues, increasing the intrinsic dipole to about 4.5 D per residue; and (2) extension of the ,-conjugation over some of the doping groups narrowed the band gaps with as much as 1 eV. The investigated bioinspired systems offer alternatives for the development of broad range of organic electronic materials with nonlinear properties. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] | ||||||||||||||||