nnEngineering coumarin-BODIPY thin-films and molecular crystals: tailoring supramolecular self-assembly for organic electronic applications

ABSTRACT Chromophoric coumarin-BODIPY derivatives bridged by an ethynyl π-bridge were investigated as supramolecular building blocks of organic semiconducting solids through X-ray analysis, UV/Vis and fluorescence measurements, and quantum chemical calculations of the frontier orbital energy depending on the chemical environment. Based on a push-pull architecture, the molecular properties of 7-(diethylamino)coumarin core end-capped with BODIPYs as well as the supramolecular self-assembly can be directed through the modification of the ethyny-aryl π-bridge and the intermolecular interactions it generates. Frontier orbital energy changes depending on chemical environment were performed, in particular, upon adsorption on a flat semiconducting surface. Coumarin-BODIPY building-blocks self-assemble into molecular crystals and highly-ordered thin-films with desirable periodic π-stacking interactions for semiconducting applications. The present work represents a convenient alternative to engineer organic semiconducting solids based on coumarin-BODIPY systems for organic electronics.