Highly Conductive Organosilica Hybrid Films Prepared from a Liquid-Crystal Perylene Bisimide Precursor

Significant anisotropic electrical conduction in organosilica films is achieved by long-range orientation of electroactive perylene bisimide (PBI) moieties in the silica scaffold. A new PBI-based organosilane precursor is designed with lyotropic liquid-crystalline properties. The PBI precursor with triethoxysilylphenyl groups exhibits a hexagonal columnar phase in the presence of organic solvents. The lyotropic liquid-crystalline behavior of the precursor enables the preparation of dip-coated films consisting of uniaxially aligned columnar aggregates of the PBI precursor on the centimeter scale. The oriented structure is successfully fixed by in situ polycondensation, which yields insoluble, thermally stable PBI-silica hybrid films. The oriented organosilica films doped with hydrazine exhibit high electrical conductivities on the order of 10(-2) S cm(-1), which are at the highest level for organosilica materials, and are comparable to those of all-organic PBI assemblies. Definite anisotropy of conductivities is also found for these films. The present results suggest that the induction of significant electrical properties in organic molecular assemblies is compatible with the structural stabilization by inorganic-organic hybridization.