In this report we present the results for the four principal tasks of this research project: Amorphous Silicon Solar Cell Characteristics and Modeling; Photocarrier Drift Mobility Measurements in hydrogenated amorphous silicon (a-Si:H), microcrystalline silicon (ic-Si:H), and polycrystalline copper indium-gallium diselenide (CIGS); Hole-Conducting Polymers as p-layer Materials for Amorphous and Crystal Silicon Solar Cells;and Infrared spectra of p/i and n/i interfaces in a-Si:H based solar cells.