Rough-Surface Gold Nanoparticles for Plasmonic Light Absorption Enhancement in Organic Solar Cells

Au nanoparticles (Au NPs) and nanoflowers (Au NFs) were utilized for improving the light absorption of a polymer-based organic solar cell without altering its thickness. Highly efficient plasmonic active layers were fabricated by embedding Au NPs and Au NFs at the bottom of the organic active layer, comprising the polymer blend of poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b; 3,4-b']dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT). For enhancing the light absorption of the organic photovoltaic cells, factors such as the size, controlled morphology, and distribution of metallic NPs were investigated to evaluate Au NPs and Au NFs as plasmonic components. The nanometer-scale surface roughness of Au NFs showed good potential for plasmonic effects and enhanced the light absorption of the cells.