Graphene can be produced by methods like growth on metal substrates by Chemical Vapor Deposition (CVD) or annealing SiC substrates . However, for industrial applications also Liquid Phase Exfoliation (LPE) is a prominent way for a high-yield production of graphene flakes . In this process a dispersion of graphene in a solvent is obtained that can be used as ink for inkjet printing. The top electrode in organic photovoltaic (OPV) solar cells is usually silver deposited by thermal evaporation . Our goal is to replace the silver grid by an inkjet printed graphene pattern, since graphene is transparent with conductivity up to ~104 S cm-1  and less expensive than silver.