Preparation and self-assembly of graphene oxide-dye composite Langmuir films: Nanostructures and aggregations

Graphene oxide (GO)-based nanocomposite films via facile and appropriate self-assembly methods have demonstrated many potential applications in wide fields. This study demonstrates a facile and clean route to prepare graphene oxide-dye composite films using Langmuir-Blodgett (LB) technique at room temperature. By electrostatic interaction between cationic dye molecules and negatively charged GO sheets as well as pi-pi interactions, GO-dye composite LB films were formed spontaneously. As a soft platform for dye molecules, GO sheets induce dye molecules to self-assemble and form highly ordered structures containing H-aggregates and/or J-aggregates. The morphological characterization results show the formation of GO-dye composite films with smooth and dense surfaces. And the spectral results reveal that dye molecules stack in well-organized aggregates on the surface of GO sheets corresponding to monomers in bulk solution. The present research work about GO-dye composite films by LB method may provide new clues to prepare organized composite films and demonstrate potential applications in many fields.