Structural Evolution of Ultrathin Films of Rhodamine 6G on Glass
Mingyu Chapman, Matthew Mullen, Elsa Novoa-Ortega, Mona Alhasani, James F. Elman, William B. Euler, J. Phys. Chem. C, 2016, 120, 8287 – 8297
Abstract
Self-organized rhodamine 6G (Rh6G) thin films on a glass substrate were prepared by spin-coating, dip-coating, and drop-coating. The thickness of the Rh6G layer strongly influences both the absorption and emission spectra, which are accounted for by monomers, exciton and excimer formation, and molecular aggregation. Submonolayer films of Rh6G show one maximum and one apparent shoulder in the absorption spectrum, but three peaks are required for deconvolution of the spectrum. As the thin film becomes thicker, the observed maximum shifts to lower energy, and a fourth peak is required for deconvolution. The emission spectra show similar features. In addition, the relative intensity of the emission is strongly dependent on the film thickness with thinner films being substantially more emissive than thick films.
