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, η 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 η 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 η 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.