Cover Picture: Multilayer Polymer Light‐Emitting Diodes: White‐Light Emission with High Efficiency (Adv. Mater. 17/2005)

White‐light‐emitting polymer diodes can be fabricated by solution processing using a blend of luminescent semiconducting polymers and organometallic complexes as the emission layer, and water‐soluble (or ethanol‐soluble) polymers and/or small molecules as the hole‐injection/transport layer (HIL/HTL) and the electron injection/transport layer (EIL/ETL), as reported on p. 2053 by Gong, Bazan, Heeger and co‐workers. Illumination‐quality light is obtained from these multilayer, high‐performance devices, with stable CIE coordinates, color temperatures, and high color‐rendering indices all close to those of “pure” white light. The cover illustration envisages the incorporation of the fabrication technique with low‐cost manufacturing technology in order to produce large areas of high‐quality white light.     

Inside Front Cover: Efficient Top‐Gate,Ambipolar, Light‐Emitting Field‐Effect Transistors Based on a Green‐Light‐Emitting Polyfluorene (Adv. Mater. 20/2006)

The inside cover shows light emission from within the channel of an ambipolar field‐effect transistor based on the green‐light‐emitting conjugated polymer F8BT in a bottom contact/top gate structure, as reported by Sirringhaus and co‐workers on p. 2708. It visually demonstrates the formation of separate electron and hole accumulation layers in ambipolar transistors and radiative recombination of charge carriers where the two layers meet (schematic), which is controlled by the applied voltages.