Source: Logan G. Kiefer, Andrew R. Falkowski, and Taylor D. Sparks, Department of Materials Science and Engineering, The University of Utah, Salt Lake City, UT

Electroplating is a process that uses electric current to reduce dissolved metal cations so that they form a thin coating on an electrode. Other thin film deposition techniques include chemical vapor deposition (CVD), spin coating, dip coating, and sputter deposition among others. CVD uses a gas-phase precursor of the element to be deposited. Spin coating spreads the liquid precursor centrifugally. Dip coating is similar to spin coating, but rather than spinning the liquid precursor, the substrate is completely submerged in it. Sputtering uses plasma to remove the desired material from a target, which then plates the substrate. Techniques such as CVD or sputtering produce very high quality films but do so very slowly and at high cost since these techniques typically require a vacuum atmosphere and small sample size. Electrodeposition doesn't rely on a vacuum atmosphere which greatly reduces the cost and increases scalability. In addition, relatively high rates of deposition can be achieved with electrodeposition.

1. Prepare Prussian Blue solution by mixing 50 mL of 0.05 M hydrochloric acid (HCl), 100 mL of 0.05 M potassium ferricyanide (K₃[Fe(CN)₆]), and 100 mL of 0.05 M iron(III) chloride hexahydrate (FeCl₃.6H₂O).
2. Create anode by wrapping approximately 8 cm of nichrome wire (NiCr) into a tight coil.
3. Prepare the cathode substrate by removing the outer coating that protects the conductive side of a 5X5 centimeter sheet of ITO coated PET.
4. Build circuit by connecting the posit

Qualitatively, the ITO coated in Prussian Blue, will become transparent when a negative potential is applied as shown in Figure 1 below. This change can be reversed by applying a positive voltage.

Figure 1: Prussian Blue in its colored and bleached states.