Optical and electrical effects of gold nanoparticles in the active layer of polymer solar cellsElectronic supplementary information (ESI) available. See DOI: 10.1039/c1jm14150c

The effects of Au nanoparticles (NPs) incorporated into the active layer of polymer solar cells (PSCs) with a newly synthesized donor polymer are investigated in detail. Our work shows that localized surface plasmon resonance (LSPR) introduced by the metallic NPs can experimentally and theoretically enhance the light absorption in the active layer of PSCs because the strong LSPR near field mainly distributes laterally along the active layer. The understanding can be applied to other metallic NP incorporated organic solar cells. Meanwhile, our results show that electrical properties can counter-diminish the optical enhancement from LSPR and thus reduce the overall performance improvement. It is important that both optical and electrical properties need to be studied and optimized simultaneously for achieving improved power conversion efficiency. The study contributes to better understanding the uses of Au NPs for enhancing PSC performances. Au NPs in the active layer (PFSDCN:PCBM) of polymer solar cell, with the chemical structure of PFSDCN and the cross section of scanning electron microscope image shown on the right.