Optical second-harmonic generation and scanning tunneling microscopy study of the self-assembly process of cyanine dyes on Br-Ag(111) substrates - art. no. 115404

摘要

Surface optical second-harmonic generation (SSHG) was used to monitor in situ the adsorption kinetics of cyanine dyes on bromide modified Ag(111) substrates and to probe the structural ordering and orientation of the self-assembled aggregates. The observed SSHG changes are compared to the nanoscopic configuration of the aggregates determined by scanning tunneling microscopy and to the macroscopic degree of the surface coverage that was deduced from optical absorption measurements. Due to substrate-adsorbate interaction, the nonlinear optical response of the surface covered with ordered aggregates is significantly different from the case of disordered adsorption. Our observations demonstrate that SSHG can be used to identify the character of molecular self-aggregation on model silver-halide surfaces. [References: 29]