Post-fabrication annealing effects on the performance of polymer: Fullerene solar cells with ZnO nanoparticles

In this study, poly(3-hexylthiophene):[6,6]-phenyl C61-butyric acid methylester (P3HT:PCBM) organic photovoltaic (OPV) devices, with ZnO nanoparticles buffer layer between the photoactive layer (P3HT:PCBM) and the cathode (Al top electrode), were fabricated. The active layer were annealed at 140 oC before depositing the Zno and top electrode. The objective of this study was to investigate the effects of the ZnO buffer layer and pre-/post-fabrication annealing on the general performance of these devices. The short-circuit current density(JSC) and open-circuit voltage (VOC) of the OPV devices were improved by the insertion of the ZnO layer and post-fabrication annealing. This can be attributed to, among other things, improved charge transport across the interface between the photoactive layer and the Al top electrode as a result of post-annealing induced modification of the interface morphology. Keywords: Organic, Photovoltaic, Heterojunction, Carriers