Enhanced performance of dye sensitized solar cells utilizing platinum electrodeposit counter electrodes

Enhanced performance was observed for dye-sensitized solar cells (DSSCs) utilizing counter electrodes based on Pt electrodeposits compared to counter electrodes based on sputtered Pt. Scanning electron microscopy of Pt electrodeposits revealed that the use of an initial cathodic overpotential pulse followed by steady electrodeposition at a mild cathodic potential yielded ∼40nm particles, compared to ∼600nm particles when no such pulse was used. Cyclic voltammetry and electrochemical impedance spectroscopy (EIS) of electrode materials suggested that Pt electrodeposits would give enhanced performance as DSSC counter electrodes compared to sputtered Pt, and this was confirmed by device testing. EIS characterization of DSSCs under illumination revealed that Pt electrodeposit counter electrodes were found to be more catalytically stable compared to sputtered Pt. The best counter electrode was based on Pt electrodeposited using an initial cathodic overpotential pulse and demonstrated charge-transfer resistance [RCT(Pt)]values of 0.6 and 0.7Ωcm2 within a symmetrical Pt/I−3/I−/Pt cell and within a DSSC, respectively.