Experimental results concerning the influence of plasmon effect from silver nanoparticles on the organic photovoltaic device performance are presented. The metallic nanoparticles (NPs) are placed on top of ITO layer using a physical vapor deposition technique. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) followed by an interpenetrated poly(3-hexylthiophene): [6,6]-phenyl-C61-butyric acid methyl ester (P3HT:PCBM) blend layer are then spin-coated. The aluminum electrode is finally evaporated on. Photovoltaic properties compared to devices without NPs are shown. A spectrophotometric characterization is carried on. Moreover, a ToF-SIMS measurement is performed in order to obtain the depth chemical profiles of solar cell containing such NPs. Silver NPs diffusion inside other layers of the cell is investigated.