Since the discovery of the polyacetylene conductivity in 1977 by Shirakawa,MacDiarmid and Heeger, Organic Electronics has been growing and establishing for a new generation of electronic devices. On one hand, the unique properties of polymeric semiconductors and conductors,udsuch as flexibility and transparency, allow the fabrication of low-cost devices over large area: the most common are the Organic Light Emitting Diodes (OLEDs) and the organicudphotovoltaic cells. On the other hand, much effort has been made to investigate new technologies and processes for the realization of high-performance organic transistors andudsensors. Among them, Inkjet Printing is a promising technique which exploits all the advantagesudof organic materials, such as low-cost and solution processability, and allows the large-scale automated fabrication of large area devices. This thesis describes the work carried outwith a piezoelectric drop-on-demand inkjet printer, theDimatixMaterials Printer 2831. The first chapter gives an overview on Organic and PrintedudElectronics state-of-art, also describing the physical principles of conductivity in organic molecules. The second chapter is totally focused on the inkjet printing technique: after a brief description of the printer employed, a detailed description of the printing process, from the ink formulation to the drop deposition and drying phenomena, is presented. Moreover the materials employed are described together with the printing parameters set for achieving the best deposition condition. Chapter 3 is devoted to tactile sensing, which is the main applicationudof the Organic Field-Effect Transistors (OFETs) in this work within the ROBOSKIN project. After an overview of inorganic tactile sensors and of the fundamentals of strain sensing in OFETs, the fabrication steps are described followed by the detailed electromechanicaludcharacterization of the various strain sensors realized. Finally, the fourth chapter describes other applications of inkjet printing developed in this work: organic diodes and photodiodes within the HYMEC project, patterned electrodes for the detection of cells electrical activity,udboth in vivo and in vitro, and a RFID tag antenna.
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