Influence of Fluorene and Spirobifluorene Regioisomerism on the Structure, Organization, and Permeation Properties of Monolayers

Abstract

9,9′-Spirobifluorene (SBF) and fluorene derivatives are extensively used as active layer in many organic electronic devices nowadays; thus, careful examination of their structure and organization in thin films and monolayers is of primary importance. In the present work, immobilization of SBF and fluorene isomers was performed via Click Chemistry coupling reaction onto well-ordered ethynylbenzene monolayers on carbon substrates. Characterization of the as-prepared monolayers was performed by classical electrochemical techniques (CV), scanning electrochemical microscopy, and atomic force microscopy, highlighting the effect of SBF and fluorene onto the structure and organization of the obtained monolayers. The significant impact of their positional isomerism on the monolayers structuration was clearly evidenced. Indeed, 2-substituted SBF and fluorene monolayers appear to be more compact and ordered than their 4-substituted analogues and are orientated parallel to the surface. These findings should have an i...