Efficient production of multiexcitons from single photons in semiconductor nanocrystals for low-cost, high efficiency photovoltaics

Solar cells represent a clean source of renewable energy. However, in order to make them competitive with traditional energy sources, the efficiency-to-cost ratio must be increased appreciably. Increases in power conversion efficiency have typically relied on iterative improvements in material quality (for both Si and non-Si systems) and/or device engineering aspects including, e.g., the use of tandem architectures. There exist, however, approaches that can potentially lead to leaps in photovoltaic performance through the use of new principles for conversion of solar energy into electricity. Proposed methods include the development of impurity band and intermediate band devices, hot electron extraction, and carrier multiplication.