This grant is in the general field of analytical and surface chemistry and in the subfield of photoelectrochemistry of molecular thin films and interfaces. Professor Neal Armstrong of the University of Arizona will study the effects of order in thin film preparations of molecules prepared by vacuum thin film deposition methods on the photoelectric response. Various methods of optical and electron spectroscopy and electron diffraction will be used. The role of interfacial substrate chemistry on the order and electronic response will also be determined. Sensor devices will be explored by microscopic engineering of the molecular composites into circuits. Multiple methods of electron and optical spectroscopy, photoconductive response and electron diffraction will be used to study the structure of phthalocyanine, perylene, donor-acceptor complexes and quinones prepared as thin films on semiconductor surfaces. In addition, modification of the layer structure by metal deposition will be studied. The determination of the effects of long and short range order in the thin film and the substrate surface chemistry on photoelectronic response will be accomplished.