Deposition of copper phthalocyanine films by glow-discharge-induced sublimation

Copper phthalocyanine (CuPc) thin films have been deposited by a recently developed plasma-based method named glow-discharge-induced sublimation (GDS). The deposition of CuPc films has also been obtained by vacuum evaporation (VE) and the comparison of the two methods shows important structural differences. FT-IR and ion beam analyses (RBS-ERDA) show that the GDS-deposited films mainly consist of integer CuPc molecules, but at increasing deposition time the incorporation of damaged molecules becomes important. X-ray diffraction, FT-IR spectroscopy, and UV-vis analysis are used to study the microstructure of the CuPc films and point out that while the VE films consist of only alpha crystallites, a more disordered structure with the presence of both alpha and beta polymorphs characterizes the GDS films. The latter films are also much more porous as shown by nitrogen physisorption measurements and SEM. Thermal treatments of the GDS films determine a decrease of the structural disorder at 250 degrees C and the complete transformation to the beta polymorph at 290 degrees C.