A Versatile Molecular Layer-by-Layer Thin Film Fabrication Technique Utilizing Copper(I)-Catalyzed Azide Alkyne Cycloaddition

We have developed a rapid and versatile layer-by-layer (LbL) thin film fabrication method using copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) or click chemistry in the construction of molecular multilayer assemblies. Mutilayers containing synthetic porphyrins, perylene diimides, and mixtures of the two have been constructed in order to highlight the versatility of this method. Characterization of thin films using UV vis absorption, water contact angle, and electrochemical techniques indicate that multilayer growth is consistent over tens of layers. Preliminary X-ray reflectivity measurements yield an average bilayer thickness of 2.47 nm for multilayers of I and 3 grown on glass. Polarized absorption measurements suggest that the dense thin films exhibit moderate ordering in their molecular structure with partial alignment with respect to the surface normal.