MicroLink Devices will increase the efficiency of multi-junction solar cells by designing and demonstrating advanced anti-reflection coatings (ARCs) that will provide a better broadband spectral response than that of conventional anti-reflection coatings. Advanced coatings of this nature are needed to realize the full performance of the forthcoming generation of multi-junction solar cells, which will contain four or more junctions. Two approaches to improving the performance of the antireflection coatings will be investigated: * develop multilayer dielectric antireflection coatings incorporating LaTiO3 to achieve significantly improved optical coupling between the coverglass and cell at the ultraviolet and infrared ends of the spectral range of interest; and * develop a structure and corresponding fabrication process to oxidize the Al-containing window layer in order to reduce the absorption of light at the short-end of the spectral range of interest, thus providing extra useable photons to the cell. These two technologies will be integrated into a hybrid design which will provide the best possible coupling of light from cover glass to cell in order to achieve the highest possible efficiency in next-generation devices containing four or more junctions. It is expected that the new coatings will enable a relative efficiency increase of at least 7%, corresponding to a 2.5% absolute efficiency increase. The reliability and radiation tolerance of these materials and the solar cells incorporating the new designs will be tested.