Clean 25 x 25 x 1.1 mm ITO covered (~260 nm, Rs = 4 -5 Ω/sq) glass plates obtained from Biotain Crystal (Fujian, China) were covered with Scotch Magic Tape® purchased from 3M (Saint Paul, MN, USA). The same laser engraver was used to cut the tape using a CAD design with the following parameters: speed 3.0, power 1%, PPI 1500. After the patterning, the tape in undesired areas is removed and the plates are submerged in etchant solution (50 g FeCl3 x 6H2O + 80 mL distilled water + 20 mL of conc. 36% HCl) for 2.5 min at 60°C. The ITO plates were then sonicated for 15 minutes each in acetone, isopropanol, and distilled water to obtain 8 clean electrodes on every plate (Fig. ).