This contribution deals with flexographic printing of nanoparticulate tin-doped indium oxide (ITO) inks for the manufacture of fine lines on PET foils and glass substrates. The development and optimization of ITO inks, based on solutions of water and ethanol, for the flexographic printing process is presented. The influence of the solvent composition, of the particle content, and of the molar mass of the binder polyvinylpyrrolidone on the printing result is shown. ITO lines with a minimum line width of around 120 mu m were printed using a printing plate with a feature size of 50 mu m; the ITO lines exhibited a thickness of around 1 mu m. Laser post-treatment was used to consolidate the top layer of the nanoparticulate ITO structures resulting in improved electrical properties; low sheet resistance values of around 300 Omega/a- were achieved

This contribution focusses on three printing techniques: inkjet printing, flexographic printing and gravure printing for the manufacture of ITO structures based on nanoparticular ITO inks. The quality and stability of nanoparticular inks depends mainly on the dispersing step and is reflected by the achieved particle size distribution. The particle size distribution of the ITO inks has a distinct influence on the optical and electrical properties of the deposited ITO structures. The optimization of nanoparticular ITO inks concerning rheological behavior, wetting behavior and resulting material performance is presented. Inkjet printing was used as a low speed method to manufacture structures in the range of 30 μm. It is shown how coffee-staining, a frequently arising problem in inkjet printing, can be prevented by different strategies. Nanoparticular ITO structures with layer thicknesses clearly below 1 μm were printed. Gravure and flexography printing are well-established industrial printing processes with printing speeds above 100 m/min. These high-speed printing processes were used to print structures on PET film and glass substrates. Different solvents, e.g., water and ethanol, solvent compositions and binder types were varied to optimize the resulting ITO structures. The printed structures in the range of 10 to 2000 μm with thicknesses down to 1 μm were evaluated concerning surface topography and electrical conductivity. The high inter-grain porosity and the used organic additives limit the electrical conductivity of nanoparticulate ITO structures. To further improve their electrical conductivity laser post-treatment of printed ITO structures was performed.

Indium tin oxide (ITO) is one of the few materials, which combines optical transparency in the wavelength range of visible light and electrical conductivity. It offers a wide range of applications in the field of optoelectronic devices such as solar cells or displays. To the present day, ITO is commonly deposited in a vacuum environment. Deposition under vacuum atmosphere is a cost-intensive process and not compatible with modern manufacturing techniques, like roll-to-roll processing. To overcome this limitation we propose the generation of ITO layers by deposition of ITO nanoparticles under atmospheric conditions. For the generation of functional devices structured layers are required. The exact damage threshold of nanoparticulate ITO layers is essential to minimize influence of the structuring process on the substrate. In our measurements we used three different substrates, spin coated layers, annealed layers and consolidated layers.

This paper applies a combined precision stage to fabricate micro-structures by two-photon polymerization (TPP). The combined stage consists of PZT and stepper-motor stages to achieve precision positioning in long displacements. First, we derive the models of the stages by identification experiments. Second, we apply robust loop-shaping techniques to improve the positioning performance of the stages. Third, we integrate the stages and develop a multi-loop control structure to provide long-stroke and high precision. In addition, we propose coordinate transformation and anti-locking functions for further improvement of the system performance. Last, we apply the combined stage to a TPP system for fabricating micro-structures, and define performance indexes based on image processing and optical qualities. The obtained performance criteria can be used to adjust controller design to improve precision manufacturing.

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