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Combining optical waveguides and organic light‐emitting diodes (OLEDs) is a key requirement for optical sensors based on organic materials. A device architecture in which the active layers of the OLED also form the waveguide structure is demonstrated (see figure), and it is shown that the choice of materials with adequate optical an electrical properties is crucial to obtain low‐loss waveguides.

Together with "back plane" electronic components and highly efficient "front plane" light-emitting devices, the successful implementation of pixel patterning is a key requirement for the success of organic light-emitting diode (OLED) displays. Prerequisites for patterning techniques include cost-efficiency, scalability to large area substrates (≥Gen 8), registration between multiple layers, and compatibility with state-of-the-art OLED technology. At present, state-of-the-art OLEDs are predominantly based on multilayered thin films of thermally evaporated small molecules and frequently contain phosphorescent emitters. This approach enables internal quantum efficiencies reaching unity [1] and operational lifetimes suitable for commercial display applications. [2,3,4,5,6] A common technique to fabricate multicolor pixelated OLED devices is shadow mask patterning. However, there are severe limitations

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The realization and performance of a novel organic field‐effect transistor—the organic junction field‐effect transistor (JFET)—is discussed. The transistors are based on the modulation of the thickness of a depletion layer in an organic pin junction with varying gate potential. Based on numerical modeling, suitable layer thicknesses and doping concentrations are identified. Experimentally, organic JFETs are realized and it is shown that the devices clearly exhibit amplification. Changes in the electrical characteristics due to a variation of the intrinsic and the p‐doped layer thickness are rationalized by the numerical model, giving further proof to the proposed operational mechanism.