Enhanced charge extraction of polymer solar cell by solution-processable gold nanoparticles

The utilization of metallic nanoparticles is one of the key strategies to improve the performance of photovoltaic devices. In this work, we elucidate the power conversion efficiency (PCE) enhancement mechanism by gold nanoparticles (Au-NPs) through a bilayer anodic buffer structure in polymer solar cells. The results show that the PCE of the device based on a Au-NP:poly(sodium-4-styrenesulfonate)/V2O5 bilayer buffer exhibits a similar to 16% enhancement compared with the device without Au-NP. By controlling the density of Au-NPs to minimize plasmonic effects, the Au-NP induced enhancement of charge extraction and crystallinity of the photoactive layer were demonstrated for the first time. Our work indicates that the plasmonic effect may not be the only factor that enhances the PCE of polymer solar cells, while providing new insights into the roles of Au-NPs in performance improvement of a bulk-heterojunction polymer solar cell.