Devices

• Transistor: organic field effect transistor to control current and voltage
• Diode: organic devices to control and rectify current
• Capacitor: organic device to store charge and smoothing of alternating voltage
• Inverter: most simple logic device made of transistors to invert an incoming signal
• Ringoscillator: organic device, consists of transistors to produce an oscillating signal
• Rectifier: device build from diodes and capacitors to rectify an electrical alternating signal

• OFET
  The transistor is the basic building block for integrated circuits. A typical polymer transistor contains 4 layers:
  • On the substrate, there is a first contact layer, which is structured to form the base of a transistor with two contacts: source and drain.
  • These contacts are covered by the polymer semiconductor.
  • The next layer is the polymer insulator, which separates the gate contact layer form the semiconductor.
  • The top layer is the gate contact layer.

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• Diode
  Diodes are needed for the rectification of alternating currents and for voltage stabilization. The diode is a device with two different electrodes called anode and cathode. In between these electrodes, there is an organic semiconductor layer. In organic diodes, the rectifying contact (so called Schottky contact) between the organic semiconductor and specific metals is used. The charge carriers can pass this metal-semiconductor contact only in one direction. Therefore, the diode allows current flow only in forward direction, whereas in the reverse direction the current flow is blocked.

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• Capacitor
  The capacitor consists of two electrodes which are separated by a dielectric (insulator). Capacitors are able to store energy in form of charge and voltage. In a DC circuit, a capacitor acts like an infinite resistance. In an AC circuit, the capacitive resistance increases with frequency. Due to those properties, capacitors are used in a variety of circuits such as resonance circuits, analog filters, and rectifiers.

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• Polymer inverter
  A polymer inverter consists of two organic transistors. The output level "out" is always the inverted input level "in". Inverters are the basic circuits for the implementation of logical functions like NAND, NOR, NOT. Every computer is built up of many complex compositions of these logical functions containing thousands of inverters.

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• Polymer ring oscillator
  The ring oscillator is a relatively simple circuit consisting of a series of several inverters. The output of each inverter stage is connected to the input of the following stage. The output of the last stage is connected to the input of the first one. Supplied with a DC voltage, it starts to oscillate at a certain frequency. Therefore, it can be used in integrated circuits to generate a clock signal.

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• Polymer rectifier
  Rectifiers are necessary to convert alternating currents into direct currents. The simplest form of a rectifier is to load a capacitor over a diode. The diode converts the input AC voltage into a pulsating DC voltage, which is smoothed by the capacitor. At the output a smooth DC voltage drops across the load resistor.

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