Multi-Technique Characterization through Multivariate Statistical Analysis of Copper Phthalocyanine Kinetic Activated Growth by Supersonic Molecular Beam Deposition

Abstract

Supersonic molecular beam deposition is a far-from-thermal-equilibrium kinetic activated growth technique, which allows the fine control of the kinetic energy of molecular species. We present a study of the growth of very thin layers of copper phthalocyanine on nanostructured surfaces of titanium dioxide nanograins; the study combines time-of-flight secondary ion mass spectrometry, Raman, X-ray photoelectron spectroscopy, and multivariate statistical analysis. Different kinetic energies and layer thicknesses were considered to investigate bond formation and surface interaction between the organic molecules and the inorganic nanograins. This study allowed the clarification of the key role of the energetic properties of the supersonic beam in the surface activation, enabling bond formation, not available with other processes at equilibrium. In particular, high kinetic energy regimes for copper phthalocyanine molecules in high-dilution seeded beams allow the formation of stronger bonds at the interface, which is useful for producing innovative nanohybrid materials having specific improved structural and chemical characteristics. The comparison among different surface characterization measurements orchestrated by multivariate statistical analysis proved to be a valuable approach for surface interaction study and interpretation.