Thu, 21 Aug 2008 14:14:24 BST CiteULike: tengli's flexible-electronics http://www.citeulike.org/user/tengli/tag/flexible-electronics CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/tengli/article/2613008 <i>Advanced Materials, Vol. 19, No. 21. (2007), pp. 3623-3627.</i><br /><br />No abstract. Printed Graphene Circuits JH Chen M Ishigami C Jang D R Hines M S Fuhrer E D Williams doi:10.1002/adma.200701059 Advanced Materials, Vol. 19, No. 21. (2007), pp. 3623-3627. 2008-03-30T13:05:40-00:00 2007 Advanced Materials 19 21 3623 3627 2007 adv-mater edw flexible-electronics graphene macroelectronics http://www.citeulike.org/user/tengli/article/2945379 <i>Nano letters, Vol. 7, No. 6. (June 2007), pp. 1643-1648.</i><br /><br />We employ scanning probe microscopy to reveal atomic structures and nanoscale morphology of graphene-based electronic devices (i.e., a graphene sheet supported by an insulating silicon dioxide substrate) for the first time. Atomic resolution scanning tunneling microscopy images reveal the presence of a strong spatially dependent perturbation, which breaks the hexagonal lattice symmetry of the graphitic lattice. Structural corrugations of the graphene sheet partially conform to the underlying silicon oxide substrate. These effects are obscured or modified on graphene devices processed with normal lithographic methods, as they are covered with a layer of photoresist residue. We enable our experiments by a novel cleaning process to produce atomically clean graphene sheets. Atomic structure of graphene on SiO2. M Ishigami JH Chen WG Cullen MS Fuhrer ED Williams doi:10.1021/nl070613a Nano letters, Vol. 7, No. 6. (June 2007), pp. 1643-1648. 2008-06-30T15:46:56-00:00 2007 Nano letters 1530-6984 7 6 1643 1648 2007 edw flexible-electronics graphene macroelectronics nano-letters http://www.citeulike.org/user/tengli/article/1572561 <i>PNAS (15 August 2007), 0706508104.</i><br /><br />Communicated by Mildred S. Dresselhaus, Massachusetts Institute of Technology, Cambridge, MA, July 11, 2007 (received for review February 23, 2007)There is strong recent interest in ultrathin, flexible, safe energy storage devices to meet the various design and power needs of modern gadgets. To build such fully flexible and robust electrochemical devices, multiple components with specific electrochemical and interfacial properties need to be integrated into single units. Here we show that these basic components, the electrode, separator, and electrolyte, can all be integrated into single contiguous nanocomposite units that can serve as building blocks for a variety of thin mechanically flexible energy storage devices. Nanoporous cellulose paper embedded with aligned carbon nanotube electrode and electrolyte constitutes the basic unit. The units are used to build various flexible supercapacitor, battery, hybrid, and dual-storage battery-in-supercapacitor devices. The thin freestanding nanocomposite paper devices offer complete mechanical flexibility during operation. The supercapacitors operate with electrolytes including aqueous solvents, room temperature ionic liquids, and bioelectrolytes and over record temperature ranges. These easy-to-assemble integrated nanocomposite energy-storage systems could provide unprecedented design ingenuity for a variety of devices operating over a wide range of temperature and environmental conditions. 10.1073/pnas.0706508104 Flexible energy storage devices based on nanocomposite paper Victor Pushparaj Manikoth Shaijumon Ashavani Kumar Saravanababu Murugesan Lijie Ci Robert Vajtai Robert Linhardt Omkaram Nalamasu Pulickel Ajayan doi:10.1073/pnas.0706508104 PNAS (15 August 2007), 0706508104. 2007-08-17T14:22:24-00:00 2007 PNAS 0706508104 energy flexible-electronics macroelectronics nanocomposite http://www.citeulike.org/user/tengli/article/1670099 <i>Science, Vol. 317, No. 5838. (3 August 2007), pp. 650-653.</i><br /><br />A freely floating polymer film, tens of nanometers in thickness, wrinkles under the capillary force exerted by a drop of water placed on its surface. The wrinkling pattern is characterized by the number and length of the wrinkles. The dependence of the number of wrinkles on the elastic properties of the film and on the capillary force exerted by the drop confirms recent theoretical predictions on the selection of a pattern with a well-defined length scale in the wrinkling instability. We combined scaling relations that were developed for the length of the wrinkles with those for the number of wrinkles to construct a metrology for measuring the elasticity and thickness of ultrathin films that relies on no more than a dish of fluid and a low-magnification microscope. We validated this method on polymer films modified by plasticizer. The relaxation of the wrinkles affords a simple method to study the viscoelastic response of ultrathin films. 10.1126/science.1144616 Capillary Wrinkling of Floating Thin Polymer Films Jiangshui Huang Megan Juszkiewicz Wim de Jeu Enrique Cerda Todd Emrick Narayanan Menon Thomas Russell doi:10.1126/science.1144616 Science, Vol. 317, No. 5838. (3 August 2007), pp. 650-653. 2007-09-18T19:02:24-00:00 2007 Science 317 5838 650 653 flexible-electronics macroelectronics mechanics http://www.citeulike.org/user/tengli/article/1044745 <i>Thin Solid Films, Vol. 460, No. 1-2. (22 July 2004), pp. 156-166.</i><br /><br />The mechanical integrity of tin-doped indium oxide (ITO) thin films sputtered onto a high temperature aromatic polyester developed for flexible display applications was investigated by means of tensile experiments equipped with electrical measurement, and carried out in-situ in an optical microscope. Attention was paid to the influence of ITO thickness, composition and crystalline microstructure, internal stress, annealing, and polymer substrate. It was observed that process-induced internal stresses were systematically compressive, and that tensile cracks in the ITO always initiated at pin-hole defect sites. A transition from stable to unstable crack growth was detected when crack length was several 100 times coating thickness. The occurrence of such a transition, which corresponded to an increase in electrical resistance equal to approximately 10%, indicated that crack propagation controlled the loss of functional performance of the device. It was moreover found that an improved surface quality of the polymer substrate, such as that obtained with planarization hard coats, was a major factor to increase the cohesive properties of ITO thin films. It was also observed that the intrinsic crack onset strain followed classic fracture mechanics scaling, in inverse proportion to the square root of ITO thickness. Mechanical integrity of transparent conductive oxide films for flexible polymer-based displays Y Leterrier L Medico F Demarco Manson U Betz MF Escola Kharrazi F Atamny doi:10.1016/j.tsf.2004.01.052 Thin Solid Films, Vol. 460, No. 1-2. (22 July 2004), pp. 156-166. 2007-01-16T18:33:20-00:00 2004 Thin Solid Films 460 1-2 156 166 flexible-electronics macroelectronics mechanics polymer-substrate http://www.citeulike.org/user/tengli/article/1044660 <i>Applied Physics Letters, Vol. 89, No. 21. (2006)</i><br /><br />Large-feature-size single-crystal Si thin-film transistors (TFTs) with fT of 1.9  GHz and fmax of 3.1  GHz were demonstrated on flexible polymer substrate. In this letter, the authors detail the fabrication process that enables TFTs, made on low-temperature flexible substrates, to operate at microwave frequencies under low bias voltages. The outstanding electrical performance results measured from these devices, such as high electron mobility, high current drive capability, and high frequency response characteristics, and the simple process procedures for producing these devices on flexible substrate make flexible electronics highly promising for power-efficient large-area radio-frequency and microwave applications. ©2006 American Institute of Physics Microwave thin-film transistors using Si nanomembranes on flexible polymer substrate Hao Yuan Zhenqiang Ma doi:10.1063/1.2397038 Applied Physics Letters, Vol. 89, No. 21. (2006) 2007-01-16T17:07:55-00:00 2006 Applied Physics Letters 89 21 AIP flexible-electronics macroelectronics polymer-substrate tft http://www.citeulike.org/user/tengli/article/993939 <i>Nature, Vol. 444, No. 7121., pp. 913-917.</i> Patterning organic single-crystal transistor arrays Alejandro Briseno Stefan Mannsfeld Mang Ling Shuhong Liu Ricky Tseng Colin Reese Mark Roberts Yang Yang Fred Wudl Zhenan Bao doi:10.1038/nature05427 Nature, Vol. 444, No. 7121., pp. 913-917. 2006-12-14T05:18:45-00:00 Nature 0028-0836 444 7121 913 917 Nature Publishing Group flexible-electronics macroelectronics http://www.citeulike.org/user/tengli/article/957721 <i>Applied Physics Letters, Vol. 89, No. 14. (2006)</i><br /><br />Cylindrical organic field effect transistors have been obtained starting from a metallic fiber used in textile processes. The metal core of the yarn, covered with a thin polyimide layer, is the gate of the structure. A top-contact device can be obtained by depositing a layer of organic semiconductor followed by the deposition of source and drain top contacts, made by metals or conductive polymers, deposited by evaporation or soft lithography. Thanks to the flexibility of the structure and the low cost of technologies, this device is a meaningful step towards innovative applications of textile electronics. ©2006 American Institute of Physics Towards the textile transistor: Assembly and characterization of an organic field effect transistor with a cylindrical geometry Maurizio Maccioni Emanuele Orgiu Piero Cosseddu Simone Locci Annalisa Bonfiglio doi:10.1063/1.2357030 Applied Physics Letters, Vol. 89, No. 14. (2006) 2006-11-22T17:05:36-00:00 2006 Applied Physics Letters 89 14 AIP etextile flexible-electronics macroelectronics ofet http://www.citeulike.org/user/tengli/article/956160 <i>Journal of Applied Physics, Vol. 100, No. 7. (2006)</i><br /><br />High efficiency white organic light emitting devices (WOLEDs) with optical outcoupling enhanced by hexagonal polymethylmethacrylate microlens arrays fabricated by imprint lithography on a glass substrate are demonstrated. Monte Carlo and finite difference time domain simulations of the emitted light are used to optimize the microlens design. The measured enhancement of light outcoupling and the angular dependence of the extracted light intensity are in agreement with the simulation. Using microlens arrays, we demonstrate a fluorescent/phosphorescent WOLED with a maximum external quantum efficiency of (14.3±0.3)% at 900  cd/m2 and power efficiency of 21.6±0.5  lm/W at 220  cd/m2. The electroluminescent spectra at viewing angles from normal to the substrate plane, to 60° off normal, remain almost unchanged, giving a color rendering index of 87. ©2006 American Institute of Physics Organic light emitting devices with enhanced outcoupling via microlenses fabricated by imprint lithography Yiru Sun Stephen Forrest doi:10.1063/1.2356904 Journal of Applied Physics, Vol. 100, No. 7. (2006) 2006-11-21T23:01:52-00:00 2006 Journal of Applied Physics 100 7 AIP flexible-electronics macroelectronics oled http://www.citeulike.org/user/tengli/article/953476 <i>Micro Electro Mechanical Systems, 2006. MEMS 2006 Istanbul. 19th IEEE International Conference on (2006), pp. 194-197.</i><br /><br />We present a finite element model for the fluidic self-assembly of microfabricated silicon components onto plastic substrates. The model encompasses both the surface energy minimization and hydrodynamic drag minimization of the microparts as they assemble at prescribed binding sites on the plastic substrate. The model is used to determine the trajectory of microcomponents as they self-assemble, and to understand the interactions between the fluid dynamics and the capillary forces acting on the components to increase the assembly yield. Modeling of Fluidic Self-Assembly for Integration of Silicon Components on Plastic SA Stauth BA Parviz Micro Electro Mechanical Systems, 2006. MEMS 2006 Istanbul. 19th IEEE International Conference on (2006), pp. 194-197. 2006-11-20T16:43:16-00:00 2006 Micro Electro Mechanical Systems, 2006. MEMS 2006 Istanbul. 19th IEEE International Conference on 194 197 fem flexible-electronics macroelectronics mechanics self-assembly http://www.citeulike.org/user/tengli/article/949370 <i>PNAS, Vol. 103, No. 38. (19 September 2006), pp. 13922-13927.</i><br /><br />We demonstrate the use of self-assembly for the integration of freestanding micrometer-scale components, including single-crystal, silicon field-effect transistors (FETs) and diffusion resistors, onto flexible plastic substrates. Preferential self-assembly of multiple microcomponent types onto a common platform is achieved through complementary shape recognition and aided by capillary, fluidic, and gravitational forces. We outline a microfabrication process that yields single-crystal, silicon FETs in a freestanding, powder-like collection for use with self-assembly. Demonstrations of self-assembled FETs on plastic include logic inverters and measured electron mobility of 592 cm2/V-s. Finally, we extend the self-assembly process to substrates each containing 10,000 binding sites and realize 97% self-assembly yield within 25 min for 100-microm-sized elements. High-yield self-assembly of micrometer-scale functional devices as outlined here provides a powerful approach for production of macroelectronic systems. 10.1073/pnas.0602893103 Self-assembled single-crystal silicon circuits on plastic Sean Stauth Babak Parviz PNAS, Vol. 103, No. 38. (19 September 2006), pp. 13922-13927. 2006-11-16T19:51:40-00:00 2006 PNAS 103 38 13922 13927 flexible-electronics macroelectronics self-assembly http://www.citeulike.org/user/tengli/article/721504 <i>Applied Physics Letters, Vol. 88, No. 20. (2006)</i><br /><br />Gold films on an elastomeric substrate can be stretched and relaxed reversibly by tens of percent. The films initially form in two different structures, one continuous and the other containing tribranched microcracks. We have identified the mechanism of elastic stretchability in the films with microcracks. The metal, which is much stiffer than the elastomer, forms a percolating network. To accommodate the large elongation of the elastomeric substrate, the metal network twists and deflects out of the plane but remains bonded to the soft substrate. Consequently, the metal film experiences only small strains and deforms elastically without suffering fatigue. ©2006 American Institute of Physics Mechanisms of reversible stretchability of thin metal films on elastomeric substrates Stephanie Lacour Donald Chan Sigurd Wagner Teng Li Zhigang Suo doi:10.1063/1.2201874 Applied Physics Letters, Vol. 88, No. 20. (2006) 2006-07-01T02:22:55-00:00 2006 Applied Physics Letters 88 20 AIP compliant-pattern deformability elastomer flexible-electronics macroelectronics platform polymer-substrate stretchability thin-metal-film http://www.citeulike.org/user/tengli/article/587300 <i>Applied Physics Letters, Vol. 87, No. 16. (2005)</i><br /><br />In recent development of deformable electronics, it has been noticed that thin metal films often rupture at small tensile strains. Here we report experiments with Cu films deposited on polymeric substrates and show that the rupture strains of the metal films are sensitive to their adhesion to the substrates. Well-bonded Cu films can sustain strains up to 10% without appreciable cracks and up to 30% with discontinuous microcracks. By contrast, poorly bonded Cu films form channel cracks at strains about 2%. The cracks form by a mixture of strain localization and intergranular fracture. The films rupture at large strains when the localization is retarded by the adherent substrates. ©2005 American Institute of Physics High ductility of a metal film adherent on a polymer substrate Yong Xiang Teng Li Zhigang Suo Joost Vlassak doi:10.1063/1.2108110 Applied Physics Letters, Vol. 87, No. 16. (2005) 2006-04-15T04:22:27-00:00 2005 Applied Physics Letters 87 16 AIP adhesion ductility flexible-electronics macroelectronics polymer-substrate thin-metal-film http://www.citeulike.org/user/tengli/article/587275 <i>Physica E: Low-dimensional Systems and Nanostructures, Vol. 25, No. 2-3. (November 2004), pp. 326-334.</i><br /><br />Conceptual hardware architecture of skin-like circuits is described. An elastomeric skin carries rigid islands on which active subcircuits are made. The subcircuit islands are interconnected by stretchable metallization. We concentrate on recent advances in stretchable thin-film conductors, by covering their construction, evaluation, and laboratory and theoretical analysis. Reversibly stretchable conductors with electrically-critical strains ranging from 10% to 100% have been made. Electronic skin: architecture and components Sigurd Wagner Stephanie Lacour Joyelle Jones Pai-Hui Hsu James Sturm Teng Li Zhigang Suo doi:10.1016/j.physe.2004.06.032 Physica E: Low-dimensional Systems and Nanostructures, Vol. 25, No. 2-3. (November 2004), pp. 326-334. 2006-04-15T04:11:53-00:00 2004 Physica E: Low-dimensional Systems and Nanostructures 25 2-3 326 334 electronic-skin flexible-electronics macroelectronics http://www.citeulike.org/user/tengli/article/587273 <i>Applied Physics Letters, Vol. 85, No. 16. (2004), pp. 3435-3437.</i><br /><br />Many flexible electronic surfaces comprise inorganic films on organic substrates. Mechanical failure of such integrated structures of stiff and compliant materials poses a significant challenge. This letter studies the stretchability of metal films on elastomer substrates. Our experiment shows that, when stretched, elastomer-supported metal films rupture at strains larger than those reported for freestanding films. We use a finite element code to simulate the rupture process of metal films. A freestanding metal film ruptures by forming a single neck. By contrast, a metal film on an elastomer substrate may develop an array of necks before rupture. While the pre-rupture necks do not change the electrical conductance appreciably, they elongate the metal film, leading to a large overall rupture strain. ©2004 American Institute of Physics Stretchability of thin metal films on elastomer substrates Teng Li Zhenyu Huang Z Suo Stephanie Lacour Sigurd Wagner doi:10.1063/1.1806275 Applied Physics Letters, Vol. 85, No. 16. (2004), pp. 3435-3437. 2006-04-15T04:07:40-00:00 2004 Applied Physics Letters 85 16 3435 3437 AIP flexible-electronics macroelectronics stretchability thin-metal-film