ZnO:Polymer Composite Material to Eliminate Kink in J-V Curves of Inverted Polymer Solar Cells

Abstract

In this work, a simple strategy is introduced to eliminate the kink observed in J-V curves of inverted polymer solar cells (i-PSCs) using a polyelectrolyte electron selective layer. By incorporating zinc oxide nanoparticles (ZnO NPs) with poly [(9,9-bis(3'-((N,N-dimethyl)-N-ethylammonium)-propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctylfluorene)] dibromide (PFN-Br), fill factor was improved by 22% and overall device efficiency was significantly improved by 48%. Moreover, the presence of PFN-Br greatly enhances film forming properties of ZnO NPs, improving efficiency by 13% compared to using just ZnO NPs. This composite interfacial layer does not require any post-processing treatment, thus providing for a facile method to solve interface problems in i-PSCs.