Ullmann-like reactions for the synthesis of complex two-dimensional materials

Abstract

Engineering two-dimensional materials through surface-confined synthetic techniques is a promising avenue for designing new materials with tailored properties. Developing and understanding methods for surface-confined synthesis of two-dimensional materials requires atomic-level characterization and chemical analysis. Small changes, atomic or molecular defects, can alter the properties of the material. Beggan et al (2015 Nanotechnology 26 365602) use surface-confined Ullmann-like coupling to polymerize thiophene substituted porphyrins on Ag(111). Upon surface deposition, the porphyrins couple with surface adatoms to create linear strands and hexagonally packed molecules. Annealing the sample results in covalently-bonded networks of thienylporphyrin derivatives. The resulting networks are studied using scanning tunneling microscopy and x-ray photoelectron spectroscopy.