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

Abstract
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 730nm. External quantum efficiency approaches unity at the peak absorption of pentacene. A 2.0% power conversion efficiency is obtained under 80mWcm−2 AM 1.5 illumination, with 8.6mAcm−2 short-circuit current. The comparison with bilayer devices suggests directions of improvement in conversion efficiency such as controlled growth of the blend layers.