Spanning force and scanning near-field optical microscopy of organized monolayers incorporating a nonamphiphilic metal dyad

A water-soluble metal complex dyad. Rh(III)-X-Ru(II), was incorporated in monolayers at the air/ water interface by cospreading with a positively (eicosylamine) or negatively (stearic acid) charged amphiphile After transfer of the monolayer onto a mica substrate via the Langmuir-Blodgett technique, a domain structure similar to that at the air/water interface was observed by scanning probe microscopy (SPM). With scanning force microscopy (SFM) we found domains with diameters in the micrometer range protruding several angstroms from the interstitial areas. The same structure was imaged with scanning near-field optical microscopy (SNOM) with joint registration of topographic features and ruthenium fluorescence. We present a model for the complex structure of the molecular film compatible with the different microscopy results.