Semitransparent organic photovoltaic cells

We demonstrate semitransparent, small molecular weight organic solar cells employing a thin silver/indium tin oxide compound cathode with a maximum transmission of (60±6) % averaged over the visible spectral range and with a power conversion efficiency, p = (0.28±0.03) % under simulated, AM1.5G, 1 sun illumination. By increasing the Ag thickness, an average transmission of (26±3) % is achieved with p = (0.62±0.06) %, a value approximately half of that obtained for the same structure employing a conventional, reflective, and thick Ag cathode. A semitransparent tandem organic solar cell with p = (0.48±0.02) % and an average transmission of (44±4) % is also demonstrated. Semitransparent organic photovoltaic cells have potential uses as tinted and power-generating thin-film coatings on architectural surfaces, such as windows and walls. The use of a transparent top electrode also significantly simplifies the design of tandem cells, relaxing requirements for the placement of different absorbing materials at the maxima of optical fields introduced by reflective cathodes.