Towards Efficient Carbon-Based Solar Cells

Our work in the last year focused on improving the sorting of semiconducting carbon nanotubes and the enhancement of the conductivity and transparency of carbon based electrodes. The active layer of our carbon solar cell is based on semiconducting single-walled carbon nanotubes; the highly selective sorting of small diameter carbon nanotube is essential for photovoltaic applications. Ideally, the active layer of a solar cell comprises of a material with bandgap near 1.3 eV corresponding to the optimal single junction bandgap for highest possible efficiency. Thus, our efforts focus on the high yield sorting process to selectively disperse semiconducting nanotubes with bandgaps around 1.3 eV. Also, all efficient solar cells comprise of a highly conductive transparent electrode to enable light transmission into the active layer and efficient carrier extraction. In this report, we first describe a high-yield method to selectively disperse semiconducting CoMoCAT (CO disproportionation on Co-Mo Catalysts) single-walled carbon nanotubes (SWNTs) with regioregular poly (3-alkylthiophenes) polymers. We observed that the dispersion yield was directly related to the length of the polymer’s alkyl side chains. Molecular dynamics simulations in explicit toluene (real