NaCl islands decorated with 2D or 3D 3,4,9,10-perylene-tetracarboxylic-dianhydride nanostructures

Abstract

The formation of PTCDA (3,4,9,10-perylene-tetracarboxylic-dianhydride) nanostrutures on Au(1 1 1)-( 22 × 3 ) covered with NaCl islands has been studied using scanning tunneling microscopy (STM). Atomically resolved STM images show that NaCl grows as (1 0 0)-terminated layers on Au(1 1 1)-( 22 × 3 ). Local atomic hexagonal packing has also been observed in the NaCl(1 0 0) layer. At submonolayer NaCl coverage, PTCDA forms two-dimensional islands on the Au(1 1 1) surface and nucleate preferentially at the NaCl island step edges. When the Au surface is fully covered with NaCl layers, PTCDA molecules form three-dimensional molecular clusters decorating the step edges of NaCl layers.