Fluorescence of plasma polymer films with embedded dye molecules

Plasma polymer thin films with embedded dye molecules (Rhodamine 6G) were deposited by alternating or simultaneous plasma polymerization and dye molecule sublimation. From films with different amounts of embedded dye molecules, fluorescence spectra as well as excitation spectra were recorded. At samples with very low amounts of embedded dye molecules, the fluorescence band was found at lambda(f)l = 550...560 nm. At higher dye amounts, the fluorescence band shifts to lambda(f)l = 590...600 nm. This was interpreted as the change from embedded isolated dye molecules at low concentrations to dye molecule clusters or nanocrystallites at higher concentrations. The appearance of a second fluorescence band at lambda(f)l = 680...700 nm was interpreted as a result of a chemical modification of the Rhodamine 6G molecules during plasma polymer deposition. (C) 1998 Elsevier Science Ltd. All rights reserved.