The need for inexpensive alternative to indium doped tin oxide (ITO) transparent electrodes is imminent for cost-efficient solution processed optoelectronic applications. ITO-free transparent electrodes can be based on inkjet-printed Silver (Ag) nanoparticles grids embedded into PEDOT:PSS buffer layers. We present an in-depth investigation of the morphological evolution of the inkjet printed Ag nanopartricle sintering process combined with an ultimate control of the printed grid design requirements for efficient ITO-free organic photovoltaics (OPVs). We report on glass/ITO-free P3HT:PC60BM and Si-PCPDTBT:PC70BM based OPVs with power conversion efficiency of 2.8% and 4.9% respectively. These devices exhibited minimal losses when compared to reference ITO-based OPVs.