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Flexible all-polymer transistor has received much attention because it is needed for the unique area of flexible circuits and displays, and the solution processing allowed with polymers would enable low-cost production. In this work, we introduce and utilize ultraviolet (UV) printing technique for the fabrication of flexible all-polymer transistor. The technique allows printing of submicron patterns of polymers without applying heat or pressure, requiring only UV light. The UV printing also allows self-aligned gate formation, which can be accomplished through a simple roll-to-roll printing. The electrical performance of the flexible transistor thus fabricated is better than that of the other flexible all-polymer transistors. [ABSTRACT FROM AUTHOR]

We developed an approach for fabricating small molecule organic light emitting diodes by solution-based processing. The approach involves dissolving a small molecule organic in a solvent, spin coating it on a mold, and then transferring the layer onto the existing organic layer on a substrate. This ability to form multilayers of small molecule organics allows one to take advantage of both the efficiency offered by the multilayer structures and the low cost fabrication made possible by the solution processing. [ABSTRACT FROM AUTHOR]

The stability of a liquid filament between two surfaces is utilized to fill nanochannels with no residue on the rest of the top surface. The stability condition is that the average contact angle of the liquid with the surfaces is less than 45°. This condition means that a liquid that wets a surface can be used, which contrasts earlier results where liquids that readily dewet a surface are required for the filling. Experimental results are presented for filling nanochannels selectively with sol-gel solutions. [ABSTRACT FROM AUTHOR]

Oxygen plasma treatment of metal gate surface is introduced as an effective method for improving the performance of the organic thin-film transistors with polymer dielectrics. The treatment results in about an order of magnitude increase in the on-off current ratio, bringing the ratio to the level of 106, and enabling a reduction in the threshold voltage. The treatment leads to the formation of an ultrathin metal oxide layer (<4.0 nm) and a more wettable gate surface for subsequent polymer coating, both of which contribute to the enhancement in the device performance. [ABSTRACT FROM AUTHOR]

A transfer fabrication technique is developed to construct embedded and inverted micro/nanostructures that cannot be readily built by other methods. Transfer patterning/printing is used for the fabrication, which involves transferring a patterned layer on a flat substrate to another substrate that has a higher work of adhesion with the layer than the flat substrate. The technique is relatively simple and fast (∼10 s). Inversion of a shape that is made possible by the transfer is the basic concept. This inversion allows fabrication of three-dimensional embedded structures through multiple stacking. The technique could open new avenues for various applications. [ABSTRACT FROM AUTHOR]

Polymer gate dielectrics have been used for organic thin-film transistors (OTFTs) primarily because of wet processability. An inorganic dielectric, if it is wet processable, can remedy many problems associated with a polymer dielectric. A siloxane-based spin-on glass is used to show that it can lead to better device performance than the best polymer dielectric known, thus paving the way to replacing the polymer dielectric for OTFTs, except in flexible device applications. [ABSTRACT FROM AUTHOR]

A coordination complex of poly(3,4-ethylene dioxythiophene)-poly(styrene sulfonate) (PEDOT-PSS) is used to enhance the performance of organic light-emitting diodes. Use of the coordination complex formed by copper results in more than doubling the device lifetime when the complex is used as the hole injection layer (HIL) in place of the usual HIL of PEDOT-PSS that is not treated. Of the possible coordination complexes of PEDOT-PSS, the coordination complex formed with copper gives the best performance. The optimal mass ratio of CuSO4 and PEDOT-PSS solution in forming the complex is found to be 0.533. Surface morphology of the organic film formed and conductivity enhancement are the main factors that determine the optimal mass ratio. [ABSTRACT FROM AUTHOR]

We introduce adhesive force lithography (AFL), a detachment-based method for patterning metal surface. In this method, all the polymer layer except for the desired pattern gets lifted up from the metal surface. The craze microstructure unique to thin polymer films on the order of 102 nm is utilized for this AFL along with a difference in adhesive force at two interfaces. Poly(urethaneacrylate) mold, which has a high enough work of adhesion with polymer, makes AFL effective. This technique is purely additive, fast (∼10 s contact time), and applicable to large area patterning (10 cm×10 cm). [ABSTRACT FROM AUTHOR]

A dry transfer technique is applied to the semiconductor layer formation in fabricating polymer thin-film transistors (TFTs). This method removes the solvent compatibility problem that is typically encountered in solution processing of polymer semiconductor and polymer gate dielectric such that any pair of the two polymers can be admitted to the fabrication of polymer TFTs. When the technique is used in place of spin coating of the active layer, the mobility increases by almost an order of magnitude, primarily because the deleterious effects are removed that a solvent can have on the underlying dielectric layer. Annealing of the active layer is also made possible by the method, which results in a significant improvement in the on/off ratio of the device. [ABSTRACT FROM AUTHOR]

We report on an ordering phenomenon of polystyrene beads that occurs when pressure is applied to the colloidal particles between a solid substrate and a patterned elastometric stamp while maintaining the temperature above the particle's glass transition temperature. The filling time is calculated using a simple two-dimensional squeeze flow theory, which successfully explains the effects of pressure, temperature, size of beads, and stamp geometries on the ordering time. [ABSTRACT FROM AUTHOR]

Sub-100 nm structures can be fabricated in tens of seconds with an aspect ratio much larger than unity by the general purpose patterning method presented here. A flexible film mold and a rapid flash heating with an infrared lamp are used in this nonphotolithographic patterning technique. Unlike other unconventional methods, the substrate surface can be made exposed and the resulting pattern height is sufficiently high for subsequent etching of the substrate. [ABSTRACT FROM AUTHOR]

We report on self-organized metal surface patterns that result when a thin bilayer of a metal on a periodically corrugated polymer layer is annealed. A theoretical basis is provided for the self-organization that is verified by experiment. The wave number of the surface pattern is determined by a square law relationship involving the corrugation wave number and the intrinsic wave number of the bilayer. The phase shift between the wave on the ridge and that on the groove is related to an uncertainty in the corrugation wave number. Free energy minimization dictates connectivity of the two waves and fidelity of the metal surface pattern. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

SF[sub 6] plasma treatment of indium tin oxide highly improves the power efficiency and the stability of the organic light-emitting diode based on poly[2-methoxy-5-(2-ethylhexyloxy)-1,4phenylenevinylene]. The treatment leads to a slight reduction in the surface roughness and a decrease in the surface content of Sn. The major effect, however, has to do with the surface incorporation of fluorine. This fluorinated surface improves the hole injection and thus the device performance. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]