Effect of Au nanoparticles on PCPDTBT:PC71BM device performance with fair comparisons

PCPDTBT:PC71BM devices with and without Au nanoparticles (NPs) were fabricated on the same electrode and compared fairly in order to clarify the effect of Au NPs on the device performance experimentally. Au NPs were deposited only on a partial area of ITO electrode, and the devices with and without Au NPs were fabricated simultaneously by spin coating of PEDOT:PSS and PCPDTBT:PC71BM. This device fabrication enables the two cells to have the same device fabrication procedures, active layer thicknesses, and material components, meaning that the difference between the two devices is only the existence of Au NPs. Consequently, the device with Au NPs showed an increase in a short circuit current with 7.2%. The IPCE behavior of the device with Au NPs was similar to the extinction spectrum of Au NPs, implying that the near field effect rather than the scattering effect of Au NPs is the dominant mechanism in the enhanced device performance.