Unsymmetrical n-Channel Semiconducting Naphthalenetetracarboxylic Diimides Assembled via Hydrogen Bonds

N-amino-N'-alkylnaphthalenetetracarboxylic diimides were investigated as thin film n-channel transistor semiconductors. Fluorinated and nonfluorinated octyl substituents produced significant activity, while a heptafluorobutyl compound was inactive. Only the fluorinated octyl compound was active in air. Electron mobility was probably limited by intergrain barriers. X-ray diffraction and DSC are consistent with a hydrogen-bonded dimer structure packed in layers parallel to the substrate. This is the first example of organic transistor activity derived from an unsymmetrical molecular unit, and demonstrates the opportunity to employ hydrogen bonds to assemble organic semiconductor films. The special stabilizing effect of fluorinated substituents is also corroborated.