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We studied the capacitance characteristics of printed p-type organic thin-film transistors (OTFTs) under various frequencies and dc bias conditions. The experimental results show that the device capacitance is largely influenced by parasitic capacitances, related to the large gate–active layer overlap areas required by the printing processes. We developed a nonquasi-static small-signal capacitance model that adopts a transmission line approach and considers the specific layout of the OTFTs, taking into account for the parasitic capacitances and, hence, is particularly well suited for printed devices. In addition, the model included parasitic impedance at the metal–organic semiconductor contacts, related to the nonohmic behavior of source–drain contacts. The model has been shown to nicely reproduce the experimental capacitance characteristics in all their features. It should be pointed out that the proposed model allows the reproducing of any device layout and could be implemented in device simulator to analyze small-signal dynamic characteristics. [ABSTRACT FROM AUTHOR]

This paper presents organic based logic and memory circuits. All those circuits are made with organic N- and P-type transistors. Organic complementary nand and nor gates were characterized and show performance equivalent to or better than the literature-reported ones. The presented memory circuits include an SRAM memory point and an edge-triggered flip-flop. The flip-flop is made of six organic two-input and three-input nand gates, representing a total of 26 organic transistors for a surface of 170 mm^2. The maximum operating frequency of this flip-flop is 220 Hz under a supply of \pm20~V. All the circuits were manufactured using a standard organic sheet-to-sheet process in ambient air. Electrical characteristics remain identical after repeated measurements. Finally, a model matching the presented circuits' behavior was carried out, permitting the design of more complex circuits. [ABSTRACT FROM AUTHOR]