Pentacene:: PTCDI-C13H27 molecular blends efficiently harvest light for solar cell applications

Solar cells exhibiting efficient photon harvesting are built from molecular blends of pentacene: PTCDI-C13H27. Absorption of the composition spans the whole visible spectrum with an onset at 730 nm. External quantum efficiency approaches unity at the peak absorption of pentacene. A 2.0% power conversion efficiency is obtained under 80 mW cm(-2) AM 1.5 illumination, with 8.6 mA cm(-2) short-circuit current. The comparison with bilayer devices suggests directions of improvement in conversion efficiency such as controlled growth of the blend layers. (c) 2006 American Institute of Physics.