Thin molecular films of neutral tetrathiafulvalene-derivatives

Thin films (thickness similar to 1 mu m) of the neutral re-donor molecules tetrathiafulvalene (TTF) derivatives tetramethyl-tetrathiafulvalene (TMTTF) , ethylenedithio-tetrathiafulvalene (EDT-TTF) and bis(ethylenedithio)-tetra thiafulvalene (BEDT-TTF) as well as of tetramethyl-tetraselenafulvalene (TM TSF) have been obtained by sublimation in high vacuum (similar to 10(-6) mb ar) on alkali halide substrates. The films grow by the well-known Volmer-We ber mechanism and are polycrystalline. The microcrystals are highly oriente d with their most densely packed molecular planes parallel to the substrate surface in order to minimize the surface (interface) energy. Incommensurat e in-plane texture is found for particular molecule-substrate systems. (C) 2000 Elsevier Science B.V. All rights reserved.