A platinum counter electrode with high electrochemical activity and high transparency for dye-sensitized solar cells

Ultra-thin platinum films were deposited on indium tin oxide (ITO) substrates in a sputtering process and used as counter electrodes of dye-sensitized solar cells. The nano-structured Pt film not only has a high transmittance (75%), but also has a lower charge-transfer resistance compared with that of thick Pt films. Under front-side illumination, the synergistic effects of the nano-structured Pt film (1.4 nm) and a reflective aluminum foil can increase the efficiency of a normal cell from 6.8 to 7.9%. For the back-side illumination, the efficiency achieved by using the present strategy is 6.6%, which is comparable to the front-side illuminated efficiency of DSSCs using thick Pt films (ca. 6.8%).