Optical and electrical characterization of organic solar cells obtained using gold and silver metal nanoparticles

Abstract Light absorption of metal nanoparticles and charge separation are two major factor for the efficiency improvement in organic solar cells. Metallic nanoparticles may exhibit surface plasmons when exposed to light. This special optical properties of metal nanoparticles make them useful in photonics, electronics and biomedical applications. In this study, gold and silver nanoparticles increased the surface roughness of the active layer. The absorption, SEM, AFM, XRD measurements of 1% ratio gold and silver nanoparticles doped active layers were carried out. Optical band gap of these films was calculated with using absorption measurements. Then, ITO/PEDOT:PSS/P3HT:PCBM:Au/LiF/Al and ITO/PEDOT:PSS/P3HT:PCBM:Ag/LiF /Al organic solar cells were obtained. It was calculated the solar cells parameters such as short -circuit current density (Jsc), open - circuit voltage (Voc), fill factor (FF) and power conversion efficiency (PCE) from current density–voltage (J-V) measurements at the room temperature. The experimental results revealed that the presence of Au and Ag nanoparticles (NPs) in the ITO/PEDOT:PSS/P3HT:PCBM/Al solar cell improved its performance with respect to undoped solar cells. For example, the power conversion efficiency was increased from 2.11% to 2.55% when doping 1 wt% of Au NPs to P3HT:PCBM and to 2.23% when doping of Ag NPs to P3HT:PCBM. This was attributed to increase of the light absorption in the presence of Au and Ag NPs doping. However, the optical band gap of films have not changed significiantly after the NPs doping.