The use of size‐controlled Ag nanoparticles (NPs) synthesized by a polyol process in the BHJ shows improved values of Jsc, FF, and the EQE. These results are due to an enhanced light absorption caused by the plasmonic field effect of Ag cluster from NPs and improved charge transport in the active layer. Ag clusters reduce the series resistance and induce an efficient charge transport system in the BHJ active layer.