Dipole-assisted self-assembly of light-emitting p-nP needles on mica

We report on dipole-assisted, self-assembled formation of p-6P and p-5P nee dles on cleaved and heated mica (0001) surfaces. Low-energy electron diffra ction (LEED) reveals that the needles are single crystalline with the (1 (1 ) over bar(1) over bar) face parallel to the surface, consisting of paralle l stacks of laying molecules oriented along the direction of microscopic di poles on the mica surface. They have submicrometer cross-sectional dimensio ns and lengths as large as millimeters. Moreover, due to the strong dipole confinement of individual molecules, the needles form large domains with pa rallel oriented entities. A pronounced optical dichroism agrees with the fi ndings from LEED. (C) 2001 American Institute of Physics.