Preparation of ITO spin-coating suspension and mITO-coated electrodes: 2 g of ITO particles (18 nm, 99.99%) were sonicated in 10 mL EtOH for 30 min before a solution of ethyl cellulose (200 mg), alcohol surfactant (proprietary nanopowder dispersant, 225 mg), and 5 g terpineol in 5 mL EtOH was added. The blue suspension was sonicated for 10 min, and the solvent was removed in vacuo to form a viscous blue paste. Afterwards, 3 mL of the paste were further diluted with 7 mL EtOH, sonicated for 10 min and used for spin-coating. Preparation of the mITO electrodes: The mITO electrodes were prepared as published in our previous work by spin coating 3 × 180 µL nanoparticle suspension in EtOH onto FTO glass slides (geometric area between 3 cm 2 and 3.8 cm 2 ), which were previously sonicated in acetone, H2O containing alkaline detergent (Deconex 11 Universal), and EtOH/ H2O (7:3) for 10 min each.