Stabilization Effect of Alkane Buffer Layer on Formation of Nanometer-Sized Metal Phthalocyanine Domains

Abstract

It is demonstrated by using scanning tunneling microscopy (STM) that, through direct deposition from solutions, nanometer-sized domains of copper phthalocyanines (both unsubstituted and octa-alkylated ones) can be formed with high stability on top of the alkane overlayer adsorbed on a graphite surface, as observed by STM. The copper phthalocyanines are close-packed within the nanodomains. The existence of an alkane layer is deemed an approach to electrically isolate the metal phthalocyanine molecules from the conductive substrate, while still allowing electrons to tunnel through. Furthermore, it appears that the introduction of an alkane buffer layer could increase the lattice stability of the CuPc domains, as revealed by STM observations.