Optically Active Thin Films Deposited by Plasma Polymerization of Dye Molecules

Abstract

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.

Luminescent 3-hydroxyflavone nanocomposites with a tuneable refractive index for photonics and UV detection by plasma assisted vacuum deposition

“…increasing the distance z between the substrates and the discharge is an efficient way to increase the concentration of integer dye molecules in the films. [9][10][11] The second working parameter was the deposition rate. It is expected that, for fixed plasma conditions, the percentage of dye molecules remaining intact during the deposition augments with the deposition rate that is proportional to the sublimation rate.…”

“…This method have been successfully applied for the development of photonic layers 6,7 with tailored luminescent 10 and optical properties, 8 as well as for the development of photonic gas sensors. 9,11 This is done by finely regulating of the interaction between the low power microwave plasma and the precursor molecules sublimated in the afterglow region. Such a control requires simultaneously adjusting different deposition parameters.…”

“…Previous investigations demonstrated that the distance between the plasma and the growing film (z) is one of the key working parameter controlling the interaction between the discharge and the precursor molecules involved in the growing of the PAVD films. [9][10][11] Therefore, this distance gradually regulates the film properties: from a highly cross-linked plasma polymer that do not retain the precursor structure (deposition at the glow discharge) to plasma films containing a controllable amount of luminescent active dye molecules (deposition in the afterglow). [9][10][11] If the distance to the glow discharge is further increased, the films are similar to those obtained by vacuum deposition in absence of a plasma.…”

“…[9][10][11] Therefore, this distance gradually regulates the film properties: from a highly cross-linked plasma polymer that do not retain the precursor structure (deposition at the glow discharge) to plasma films containing a controllable amount of luminescent active dye molecules (deposition in the afterglow). [9][10][11] If the distance to the glow discharge is further increased, the films are similar to those obtained by vacuum deposition in absence of a plasma. 11 As a novelty in the present research the influence of the deposition rate (controlled by the sublimation speed) is also investigated.…”

Polymeric Dye Film Deposition in Vacuum

“…Authors reported, that the part of the dye molecules was damaged. Thus, more dyes were "polymerized" using plasma with an aim to produce stable films [6][7][8][9]. From IR-spectra authors concluded, that the dye molecules were incorporated in the "polymer" film, but no another compound, except dye, was in the plasma.…”