When Shirakawa, Heeger, and MacDiarmid created the new field of polymer electronics in 1977, the connection to the well-established printed media market was an obvious step in the direction of mass production. Printing is quite an enticing technique since it is associated with high speed, precision, and cost efficiency, attributes that this technology has earned in the century-long tradition of the graphical industry. In spite of this long tradition, it is not easy to establish printing as a production technique for electronics: the requirements for printing quality are much higher for electronic devices than for graphical applications, while the materials are much more difficult to handle. Therefore, printing cannot be seen as a black box for deposition anymore. Since it has entered the electronic industry, research focuses more and more on understanding the physics behind this technique. Our concept is to subdivide printing into a sequence of processes and to explain each of them on the grounds of physical, thermodynamic, or hydrodynamic models. We want to convince the reader of the necessity of systematic access to printing-related challenges that he or she may already have encountered in the lab: Why are some materials harder to process than others? Which technique is optimal for my material? How can I check whether my printed samples are OK or what has gone wrong? In this chapter, we explain the printing process by following the whole process chain. We start with an introduction to functional fluids. After a listing of requirements and fluid parameters, we introduce the substeps of printing. In the following section, we describe the most common printing techniques by showing their working principle, applying the previously defined substeps to the specific system, and sharing practical experiences with the reader.

Organic electronics is promising to be one of the groundbreaking technologies to revolutionize our everyday lives by including new functionalities into nearly any item. Cost is the most significant barrier, since new functionalities should not increase the price of the product dramatically. Roll-to-roll production is the solution to overcome the price barrier. In combination with integrated laser processes new possibilities are opened up for cost-efficient, versatile and high throughput manufacturing lines (Fig. 1).

Organic electronic devices like organic thin film transistors with micron or even sub-micron sized features can be fabricated at high throughput by fast printing methods combined with high resolution laser patterning. In addition, such an approach is of interest for applications with lower requirements in resolution, such as OLEDs or OPV. Due to its high flexibility and adaptability to almost any material or material system, laser processing is a perfect tool for the production of organic electronics. In all the applications above, it is of severe importance not to cause damage to adjacent material or layers by laser radiation. For transparent conductive layers laser-induced damage can lead to changes in conductivity, transparency or material composition (e.g. oxidation). Therefore, a comprehensive study was performed to investigate the influence of laser radiation below ablation threshold on material properties of transparent conducting layers (e.g. ITO, PEDOT/PSS). Samples were irradiated by a large range of wavelengths, reaching from the deep UV (193 nm) up to near IR (1064 nm). To identify changes in material properties the samples were characterized by microscopic methods like high resolution laser scanning microscopy and conductive atomic force microscopy. Also spectroscopic methods like UV/VIS/NIR absorption spectroscopy as well as X-ray photoelectron spectroscopy were used in order to determine changes in conductivity and material composition.

In this paper we present a potentially fast method for high resolution micro structuring of organic electronics via laser patterning. An investigation of the absorption spectrum in the UV/VIS regime of poly (3,4-ethylene dioxythiophene) poly (styrene-sulfonate) (PEDOT/PSS) has shown that UV-laser radiation should be used for optimal laser ablation of the material. Hence, the ablation characteristics of PEDOT/PSS with two different excimer lasers are compared with each other. The optimal fluence for the ablation of the material has been determined. The lasers used in this study are ArF (λ=193nm) and KrF (λ=248nm) excimer lasers.

Micro-hairs are profound elements widely used in nature. A great variety of animals use them as sensors to gather information about their surroundings. To artificially fabricate these kinds of sensors, we present a method to produce micro-hairs made of polydimethylsiloxane (PDMS). We investigated the laser micro-drilling of wax and polycarbonate (PC) substrates with a 193-nm ArF laser to produce molds suitable for casting micro-hairs. Especially PC molds lead to high-quality micro-hairs. Thus, laser ablation of PC was intensively studied. In order to obtain micro-hair arrays, experiments where performed to optimize the casting techniques of PDMS in PC molds. The possibilities and limitations of the investigated method of micro-hair production are presented.