(167g) Photocatalytic Photosystem I/PEDOT Composite Films Prepared By Vapor Phase Polymerization

Photosystem I (PSI) is an integral membrane protein complex contained within the chloroplast granum of plants and cyanobacteria. The product of over a billion years of systematic evolution, PSI is adapted to the earthâ??s climate and sunâ??s radiant energy profile. PSI transduces blue-violet and red light, sustaining 1.1eV of stored energy in <100ps by way of a cascade of irreversible internal reactions. Internal quantum efficiency for this process is nearly 100%, making PSI a model photodiode. As such, PSI has garnered interest as a macromolecule for use in photovoltaic and photocatalytic systems in a variety of roles. Recently, there have been efforts to include PSI within composite films, whereby the high potential and photocatalytic efficiency of PSI is coupled with an electrically conductive matrix.

We describe a versatile technique to fabricate photocatalytic composite films containing PSI and a chosen intrinsically conductive polymer (ICP). Iron (III)â??a friedel crafts catalystâ??is added to protein solutions by way of water soluble FeCl₃. Drop casting of these solutions on a substrate of choice is followed by contact with low temperature (40^oC) monomer vapor of a well-studied ICP, poly(3,4-etylenedioxythiophene) PEDOT. In minutes, a ~200 nm thick polymer/protein composite is grown. Composite films retain the high conductivity of the used ICP and the characteristic absorbance and photocatalytic capabilities of PSI multilayers. Vapor phase processing allows versatility in choice of underlying substrate.