and the substrates were then thoroughly washed with de-ionized water and dried with argonflow. In the following step, the substrates with the nanorods were functionalized by dipping them in a nickel phthalocyanine-tetrasulfonic acid tetrasodium salt (NiPc) solution (0.5mg/mL) for 1 h. Fig. 1 schematically shows the different steps involved in the fabrication process.