Surface forces exerted on small liquid droplets on heterogeneous surfaces can be exploited for bottom±up hierarchical assembly of functional nanostructures. We demonstrate here a self-aligned additive printing technique that uses standard inkjet-printing equipment, but is capable of achieving sub-100 nm resolution without any lithographic step. Very small gaps between two printed electrodes are defined uniformly and with high yield by controlling the receding contact-line motion of liquid conductive-ink droplets that are repelled by and flow off the surface of a previously deposited electrode. We illustrate the potential of this technique by fabricating inkjet-printed polymer transistor circuits with sub-100 nm channel lengths that are more than two orders of magnitude faster than previous printed organic-transistor circuits.The application of graphic-arts printing techniques to liquid-based, additive patterning of functional materials promises to provide a new paradigm for manufacturing of large-area, low-cost electronic circuits on flexible substrates. [1,2] However, current resolution achievable with straight inkjet, offset, or gravure printing is limited to 20±50 lm. [3,4] The question of whether printing will be capable of submicrometer-feature definition is a crucial one. It will decide whether printingbased manufacturing will be able to embark on a roadmap of feature-size reductions and corresponding performance enhancements analogous to those of silicon integrated circuits, or whether the challenges of accurately positioning liquid droplets and controlling their flow on the substrate will prevent the use of printing in applications where high switching speeds require submicrometer features. It will also decide whether additive printing will become an important tool for bottom±up nanotechnology, e.g., interfacing with functional nanostructures self-assembled in the liquid phase from smaller building blocks. In principle, printing fulfils many of the material-compatibility requirements for liquid-based self-assembly, but for many systems a key requirement is a patterning resolution of less than 100 nm in order to match the length scale over which supramolecular structure formation can be controlled with high precision. [5,6] Here we demonstrate a novel bottom±up, self-aligned inkjet printing technique that is capable of defining sub-100 nm critical features with two simple additive printing steps using standard inkjet-printing equipment without the need for any lithography or precise relative alignment. The method comprises the steps of a) inkjet printing a first conductive pattern onto the substrate; b) selectively modifying the surface of the first conductive pattern to be of low surface energy without modifying the surface of the substrate; and c) inkjet printing a second conductive pattern that partially overlaps the first conductive pattern, but does not require precise relative alignment. The droplets of the second pattern are repelled by and flow off the low-energy surface of the first pattern and dr...

Controlling the morphology of soluble small molecule organic semiconductors is crucial for the application of such materials in electronic devices. Using a simple dip-coating process we systematically vary the film drying speed to produce a range of morphologies, including oriented needle-like crystals. Structural characterization as well as electrical transistor measurements show that intermediate drying velocities produce the most uniformly aligned films.

ISSCC 2008 PAPER CONTINUATIONS Figure 15.3.7: Pictures of the transponder foil and load modulator foil (top), the double half-wave rectifier foil (bottom left) and the 6" wafer full of transponder chips (bottom right).

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The inherently low resolution of inkjet printing on unpatterned surfaces can be overcome by selective surface modification of a first printed pattern, resulting in hydrophobic repulsion of subsequently deposited aqueous polymer dispersions. This technique, reported by Sirringhaus and co‐workers on p. 997, is capable of achieving sub‐100  nm resolution without any lithographic step. The cover shows an array of polymer transistors patterned with this method on three different length scales, as well as a schematic of the process.