Effect of dispersion of gold nanoparticles on the properties and alignment of liquid crystalline copper phthalocyanine films

The inclusion of hexadecylamine capped gold nanoparticles (AuNPs) into the ordered matrix of hexagonal columnar mesophase of copper phthalocyanine (CuPc) has been investigated. The effects of AuNPs on the liquid crystalline behaviour, optical and electrical properties of CuPc films is investigated by different physical methods. The molecules orientation in the films of CuPc and its composites with AuNPs, deposited on the surface of one substrate and between two electrodes, is studied by polarized Raman spectroscopy and polarized microscopy. It has been shown that thin films of the composites confined between ITO and Al electrodes are characterized by homeotropic alignment while no homeotropic alignment was observed in films deposited on ITO substrate with air constituting the upper interface. The I(V) dependences for the films confined between ITO and Al electrodes were measured. Appreciable enhancement of the DC conductivity is observed in the case of composites containing gold nanoparticles.