If it were possible to print electronic components simply on paper or film, intelligent packages could be produced at low cost, for instance. Printed electronics is an attractive proposition also for all large-area applications, such as wallpaper equipped with light emitting diodes, or films fitted with solar cells for use on windows and façades. Electronics produced by printing at present employs mostly organic semiconductor materials which, however, tend to be decomposed over time. Moreover, these components are not fast enough for use in sophisticated applications. KIT scientists have found possibilities to increase the speed and longevity of printed electronics, especially of field effect transistors (FET). These transistors consist of a source, a drain, and a gate. Source and drain are connected by a channel made up of a semiconducting material. The gate electrode, which controls the current between the source and the drain, is applied to a non-conducting material (dielectric). The field effect transistor developed at the KIT contains nanoparticles of an inorganic semiconductor material, which constitute the channel. The dielectric is an electrolyte which is liquid when applied, penetrates into the pores of the channel, and later is cured, becoming a transparent solid. A voltage applied between the source and the gate builds up an electric field which causes electric three-dimensional double layers to be produced on the surfaces of the semiconductor nanoparticles. This allows three-dimensional control and a layered structure, which is advantageous in high-speed transistors. A field effect transistor is the faster the narrower the channel between the source and the drain. If the component is to be made by printing, the minimum width of the channel is limited by the resolution of the printing process, which is around 20 µm. However, in a design consisting of various layers, only some 10 nm wide layers can be printed on top of each other.