The search for alternative energy sources is attracting the attention of governments, industry and researchers around the world. One of the most promising energy sources is the solar energy and excessive efforts are invested in exploring novel approaches for fabrication of efficient, low-cost solar cells. A good candidate for the next generation solar cells is a nanomaterial based photovoltaic technology. Advances in the synthesis and the characterization of semiconductor nanocrystals (NCs) have greatly improved the ability to tailor their electronic and optical properties. Highly efficient NC based solar cells can be fabricated on large areas at low cost. In this research, a unique multi-layer device architecture is used to achieve ultra-high-efficiency NC solar cells.