The goal of this STTR program is to employ nanostructured materials in advanced device designs to enhance the tolerance of solar cells to extreme conditions while achieving high solar electric power conversion. By using InN-based quantum dots embedded within a higher band gap GaN barrier material, a larger fraction of the solar spectrum can be harnessed while minimizing the effects of high temperatures and high-energy radiation with this promising photovoltaic device. The wide range of energies accessible to InN-based materials provides a unique flexibility in designing quantum dot solar cell structures. The Phase I effort will focus on identifying, both theoretically and experimentally, the most promising device designs. Ultimately our approach provides a pathway for realizing solar cells with over 2,000 W/kg of specific power and power conversion efficiency approaching 60%.