Polymeric film deposition by ionization-assisted method for optical and optoelectronic applications

Abstract

This paper reviews the deposition of polymeric thin films by using the ionization-assisted deposition (IAD) method. Three methods for polymer film formation are described. The simplest method is the direct evaporation of polymer material, which can be applied only to limited materials such as low-molecular weight polyethylene and polytetrafluoroethylene. The other two methods involve a polymerization reaction on the substrate surface following the deposition of monomer source materials. The first of these methods uses stepwise reaction of two bifunctional monomers co-deposited on the substrate. Polyurea films are synthesized from di-isocyanate and diamine. The IAD method has a possibility of aligning the dipole orientation in the process of synthesis, which leads to the increase of the piezoelectric constant of the deposited film. Another method involves a chain reaction of single monomer material that has a polymerizable group. It is found that the IAD method enables vinyl polymerization of some of the acrylate monomers. A vinyl polymer containing a triphenylamine group is prepared with this method and is applied as the hole transport layer of a light emitting diode. The deposition polymerization is effective in improving the device stability.