Structural and spectroscopic characterization of Cu(II) [tetrakis-(3,3-dimethyl-l-butoxycarbonyl)] phthalocyanine thin films deposited by the Langmuir—Blodgett technique

Langmuir-Blodgett (LB) films of Cu(II) [tetrakis(3,3-dimethyl-1-butoxycarbonyl)] phthalocyanine were prepared and characterized by X-ray diffraction, and polarized UV-Vis and electron paramagnetic resonance (EPR) spectroscopies. It was found that the phthalocyanine molecules deposited on quartz and polyethylene terephthalate (pet) are arranged edge-on on the substrate with the normal to the molecular plane that lies close to the plane of the film. Polarized W-Vis spectra of films show in-plane anisotropy in the orientation of molecules for LB films deposited on quartz and on pet. EPR spectra also, assigned to CU2+ interacting species, were detected for the LB films deposited on pet. The spectra show a marked in-plane anisotropy of the Zeeman interaction when the magnetic field lies in the support plane. The analysis of their angular dependence confirms that the plane of the phthalocyanine molecule is almost perpendicular to the film plane and gives evidence that the in-plane orientation anisotropy arises from two different distributions of orientations pinned around two average orientations having an angle of 68 degrees between them.