Enhanced Absorption in Organic Solar Cells by employing Plasmonic Nanostructures

In this paper, we present organic solar cells (OSCs) containing plasmonic silver nanostructures in the active medium poly[[9-(l-octylnonyl)-9H-carbazole-2,7 -diyl]-2,5-thiophenediyl-2, 1,3-benzothiadiazole-4,7 -diyl-2,5-thiophenediyl] (PCDTBT):[6], [6]-phenyl C71 butyric acid methyl ester (PC71BM). Finite-difference time-domain (FDTD) modeling was employed to simulate the interaction of incident light with plasmonic nanostructures of different shapes, leading to a broadband absorption enhancement in the OSCs. It is demonstrated that this enhancement is primarily due to enhanced far field scattering - localized surface plasmon excitation - from the nanostructures in the active medium. We demonstrate a 25.28% increase in the short circuit current density, $\mathrm{J}_{\text{SC}}$ for the OSCs containing hexagonal nanodiscs in the active medium.