Mixed Plasmonic Nanoparticles for Enhanced-Performance Organic Solar Cells

Photovoltaics (PVs) are considered as a promising approach to provide a renewable and environmentally friendly energy source. Ease of process, low-cost, light-weight, optical tunability, mechanical flexibility, semi-transparency and low-temperature fabrication makes organic solar cells (OSCs) a competitive choice in comparison with the currently dominating inorganic polycrystalline and Si-based devices. To commercialize the polymer PVs, however, higher efficiencies will be required. The reason behind the undesirable performance of organic devices is their insufficient light harvesting efficiency which could be enhanced by exploitation of localized surface plasmon resonance (LSPR). The intensified local electric field in the vicinity of metal nanoparticles (MNPs), which is induced by excitation of LSPR, is expected to intensify the light harvesting capacity inside the active layer of OSCs. In this study, the performance of polymer:fullerene bulk heterojunction (BHJ) OSCs incorporated with various MNPs are investigated. We analyzed the enhancement in optical absorption of poly(3-hexylthiophene):3´-phenyl-3´H-cyclopropa [1,9][5,6] fullerene-C60-Ih-3´-butanoic acid methyl ester (P3HT:PCBM) active medium while MNPs with different shapes, sizes and densities are deposited on top of the indium tin oxide (ITO) modified anode. The characterization results revealed both optical and electrical improvements of fabricated OSCs. A remarkable enhancement of 30% in the power conversion efficiency (PCE) has been achieved, attributed to the plasmonic effect observed in the MNPs