Performance improvement of inverted polymer solar cells by incorporating Au and ZnO nanoparticles bilayer plasmonic nanostructure

Abstract

In this work, we investigate the near-field plasmonic resonance effect of Au nanoparticles (NPs) on the performance of inverted polymer solar cells by using solution-processed ZnO nanoparticles as the electron transport and buffer layer. The short-circuit current density, JSC, of PTB7:PC71BM based inverted polymer solar cells, is increased by more than 10% after incorporating Au NPs due to the plasmonic resonance enhancement effect, while open-circuit voltage, VOC, and fill factor, FF, are either stay the same or slightly increased, leading to an improved power conversion efficiency of ηP=8.23%. The layer of ZnO NPs is proved to be very important to achieve such high device performance. The electron transport within devices can be greatly facilitated due to the high electron mobility of ZnO NPs, while the direct contact between Au NPs and active layer can be prevented by ZnO buffer layer, therefore effectively suppressing the interface exciton quenching and improving the device efficiency.