Liquid crystalline octasubstituted lead(II) phthalocyanines: effects of alkoxy and alkylthio substituents on film alignment and electrical properties

Abstract

Octasubstituted lead(II) phthalocyanines containing alkylthio- and alkoxy-groups in peripheral positions have been synthesized and characterized using H-1 and C-13 NMR, UV-Vis, IR and mass spectroscopies as well as elemental analysis. The mesogenic properties of the octasubstituted lead(II) phthalocyanines have been investigated by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction. The sandwich structures ITO/PbPc/In were prepared to investigate the J(V) characteristics of thin films of these molecules. The dissimilar behavior of the films before and after heat-treatment is expected to result in changing the alignment inside the columnar stacking of the molecules in the films.