Many believe that solar panels will need to have a power conversion efficiency greater than 25% and a cost below $0.4/W to revolutionize how the world's population obtains its electricity. We believe that the most promising approach to reaching this goal is to make tandem solar cells with a high band gap solar cell harvesting the high-energy photons and a lower bandgap solar cell harvesting the low-energy photons. This approach has already been used to make solar cells with power conversion efficiency greater than 45%. The remaining challenge is to figure out how to make the tandems at low cost.
Dynamic windows utilize electrochromic materials, which change their transmission characteristics upon application of a voltage, to modulate the transparency of a window towards visible and/or infrared light. The widespread implementation of affordable and reliable dynamic windows in buildings would result in substantial energy savings by minimizing lighting and heating costs. Currently, however, several shortcomings have confined dynamic windows to niche applications such as in luxury cars and airplane windows.