Pentacene–fullerene bulk-heterojunction solar cell: A computational study

• Optoelectronic properties of pentacene–fullerene nanocomposites are presented.
• Photovoltaic properties of the nanocomposites are predicted.
• DFT/TDDFT results are in well agreement with available experimental results.
• Calculated results give a direction for optimizing device performance.

We perform DFT/TDDFT calculations to study the optoelectronic properties of some pentacene-based organic molecules and their derivatives, which can serve as donor moiety when blended with fullerene acceptors in the bulk-heterojunction solar cell model. We are motivated by a recent experiment in which an unoptimized device was shown to have a good photovoltaic performance and we aim to further improve the efficiency of this device. We try to optimize the photovoltaic properties on the basis of a quantum-mechanical calculation of the frontier energy levels and of the absorption properties of individual molecules and of the molecule–fullerine composite.