Dimerization of Rhodamine B in Alumina sol and corresponding dip-coated film

•The RB-doped alumina sol was used to prepare dip-coated film.•In the concentrated sol H-dimers are formed whereas in the corresponding film J-dimers prevail.•As the dip-coated films exposed to high humidity environment and isopropanol vapor, J-dimer to H-dimer transition and J-dimer dissociation are observed respectively.

The alumina sol doped with rhodamine B (RB) was concentrated to different degree and then dip-coated to prepare thin film. Dimerization of RB happens in the concentrated sol and the dip-coated thin film. As the sol concentrated, H-dimers are presented whereas in the dip-coated film J-dimers are displayed. When the dip-coated film is exposed to high humidity environment, J-dimer will transfer to H-dimer. Put the film in isopropanol vapor, J-dimer dissociates to monomer.

Graphical abstractDimer formation, transformation, and dissociation in dip-coated film.Figure optionsDownload full-size imageDownload as PowerPoint slide