Stepwise Formation and Characterization of Covalently Linked Multiporphyrin−Imide Architectures on Si(100)
By Jiao, Jieying; Anariba, Franklin; Tiznado, Hugo; Schmidt, Izabela; Lindsey, Jonathan S.; Zaera, Francisco & Bocian, David F.
Published in Journal of the American Chemical Society
2006
Abstract
A major challenge in molecular electronics and related fields entails the fabrication of elaborate molecular architectures on electroactive surfaces to yield hybrid molecular/semiconductor systems. A method has been developed for the stepwise synthesis of oligomers of porphyrins linked covalently via imide units. A triallylporphyrin bearing an amino group serves as the base unit on Si(100), and the alternating use of a dianhydride (3,3',4,4'-biphenyltetracarboxylic dianhydride) and a porphyrindiamine for reaction enables the rapid and simple buildup of oligomers composed of 25 porphyrins. The properties of these porphyrin multad" films on Si(100) were interrogated using a variety of techniques. The charge densities of the redox-active porphyrin oligomers were determined via electrochemical methods. The stepwise growth was evaluated in detail via Fourier transform infrared (FTIR) spectroscopy and by selected X-ray photoelectron spectroscopic (XPS) studies. The morphology was probed via AFM methods. Finally