New Columnar Zn-Phthalocyanine
Designed for Electronic
Applications
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Abstract
Columnar liquid crystals are composed of disk-shaped
aromatic molecules
surrounded by flexible side chains, where molecules self-assemble
in columns and thereby form large surface-oriented domains. These
systems are known for their good charge and exciton transport along
the columns, with mobilities approaching those of aromatic single
crystals. Such semiconducting materials are promising for devices
applications, since the output efficiency can be tuned by properly
aligning columns. In the work presented here, the synthesis and characterization
of a new Zn-phthalocyanine (ZnPc) is described which exhibits remarkable
properties, such as hexagonal columnar order, achieved by cooling
down from the isotropic phase to room temperature. Such order was
confirmed by optical microscopy and X-ray diffraction experiments.
Diodes were constructed using spin-coated films, and the conductive
properties were investigated by current versus voltage analysis, where
mobilities of 10<sup>–3</sup> and 10<sup>–2</sup> cm<sup>2</sup>/(V s) were obtained for the nonannealed and annealed films,
respectively