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Abstract

Materials commonly used in the carrier transport layers of organic light-emitting diodes, where transport occurs through the bulk, are in general very different from materials used in organic field-effect transistors, where transport takes place in a very thin accumulation channel. In this paper, the use of a high-performance electron-conducting field-effect transistor material, diperfluorohexyl-substituted quaterthiophene (DFH-4T), as the electron-transporting material in an organic light-emitting diode structure is investigated. The organic light-emitting diode has an electron accumulation layer in DFH-4T at the organic hetero-interface with the host of the light-emitting layer, tris(8-hydroxyquinoline) aluminum (Alq3). This electron accumulation layer is used to transport electrons and inject them into the active emissive host-guest layer. By optimizing the growth conditions of DFH-4T for electron transport at the organic hetero-interface, high electron current densities of 750 A cm−2 are achieved in this innovative light-emitting structure.