First principles modeling of panchromatic dyes for solar cells applications.

The state-of-the-art dye in Gr\"atzel solar cells, N719, exhibits a total solar-to-electric conversion efficiency of 11.2\%. However, it severely lacks absorption in the red and the near infrared regions of the electromagnetic spectrum, which represent more than 70\% of the solar radiation spectrum. Using calculations from first principles in the time-dependent domain, we have studied the electronic and optical response of a novel class of panchromatic sensitizers that can harvest solar energy efficiently across the visible and near infrared regions, which have been recently synthesized [A. El-Shafei, M. Hussain, A. Atiq, A. Islam, and L. Han, J. Mater. Chem. {\bf 22}, 24048 (2012)]. Our calculations show that, by tuning the properties of antenna groups, one can achieve a substantial improvement of the optical properties.