Optically active thin films deposited by plasma polymerization of dye molecules

Colored and fluorescent thin films are prepared via polymerization of dye molecules by interaction with a remote plasma of Ar while they are sublimated on a substrate. The films are formed by a crosslinked matrix of fragments of the original dye and some unreacted molecules. Films made of Ethyl Red or Rhodamine 6G dyes are characterized and studied with regard to their optical properties. Plasma characterization by optical emission spectroscopy (OES) shows the fragmentation of the evaporated dye molecules by interaction of the dye molecules with the electrons of the plasma. The electron energy seems to be the main parameter controlling the polymerization degree of the films. The process is very interesting for the deposition of thin films containing functional molecules.