High-efficiency organic solar cells

Organic solar cells based on merocyanine dyes have exhibited sunlight efficiencies in excess of 1% at ∼100 mW/cm2. This represents a significant improvement over previously reported values and brings such devices into the realm of practicality. The devices exhibit Voc’s as high as 1.2 V but are presently limited by field-dependent energy-dependent quantum efficiency. Though monochromatic efficiencies approaching 100% occur at high photon energies, these diminish to ∼35% at the main absorption peak in the visible. Based upon sunlight absorption, theoretical efficiencies for these devices appear high.