STRUCTURAL CHARACTERISTICS OF A UNIQUELY NANOSTRUCTURED ORGANIC THIN-FILM

The red pigment N,N-di(3,5-xylyl)perylene-3,4:9,10 bis(dicarboximide) is easily vacuum deposited and when subsequently vacuum annealed, a 1500 angstrom transforms to a random array of crystalline whiskers of extremely high number density (approx.50 whiskers per square micron), uniformly oriented with their long axes normal to the substrate. We have previously reported on growth kinetics of the whiskers by surface diffusion to screw dislocations. Here we present a structural characterization of the whiskers using transmission electron microscopy and selected-area electron diffraction. The whiskers' dimensions, size distributions, specific surface area, and lattice structure are determined. They are lath shaped with mean cross-sectional widths and thicknesses of 525 ± 120 and 270 ± 75 angstrom, respectively. Surprisingly, the lattice is determined to be body centered cubic with a 14.5(4) angstrom lattice constant. The growth tips are in the [211] direction, bounded by(111) and (011) side planes. The latter side plane surfaces are decorated with steps lying parallel to the long axis, and spaced approx.44 angstrom apart. The pigment whiskers can be readily sputter or vapor coated over large areas to provide conformally coated nanostructure-sized features with numerous novel chemical and physical properties.