NOVELTY - N,N'-bis(1,1-dihydroperfluoro-3-5C-alkyl)perylene-3,4:9,10-tetracarboxylic diimides are used as charge transport materials or exciton transport materials.    USE - The N,N'-bis(1,1-dihydroperfluoro-3-5C-alkyl)perylene-3,4:9,10-tetracarboxylic diimides of (I) are used as charge transport materials or exciton transport materials in excitonic solar cells. They are used as electron conductors in organic field-effect transistors, organic solar cells, and organic LEDs. Compounds of (I) are used as semiconductor material in organic electronics, preferably as n-semiconductor in organic field-effect transistors; as active material in organic photovoltaics; as fluorescent dye in a display based on fluorescence conversion; in a light-collecting plastics part, which is optionally combined with a solar cell; as a pigment dye in electrophoretic displays; as a fluorescent dye in an application based on chemoluminescence; and in organic field-effect transistors for a substrate useful for a semiconductor unit (claimed). The field-effect transistor is a thin-film transistor. Uses include but are not limited to production of integrated circuits, microprocessors, microcontrollers, static RAM, tunnel diodes, biological and chemical detectors or sensors, radio frequency identification tags, laser welding, heat management, and converters.    ADVANTAGE - Compounds of (I) are air-stable with exceptionally high charge mobilities and have high on/off ratio. They provide organic LEDs with high efficiency. When the compounds of (I) are combined with other semiconductors and the position of the energy levels results in the other semiconductors functioning as n-semiconductors, the compounds (I) may also function as p-semiconductors in exceptional cases.    DETAILED DESCRIPTION - N,N'-bis(1,1-dihydroperfluoro-3-5C-alkyl)perylene-3,4:9,10-tetracarboxylic diimides of formula (I) are used as charge transport materials or exciton transport materials.    R-a, R-b=perfluoro-2-4C-alkyl.    INDEPENDENT CLAIMS are included for:    (1) an organic field-effect transistor comprising a substrate having a gate structure(s), a source electrode, and a drain electrode, and compound(s) (I) as n-semiconductor;    (2) a substrate comprising organic field-effect transistors, at least some of which comprising compound(s) (I);    (3) a semiconductor unit comprising substrate(s); and    (4) a process for depositing compound(s) (I) on or applying compound(s) (I) to a substrate by a gas phase deposition process or a wet application process.