Electroless platinum counter electrodes with Pt-activated self-assembled monolayer on transparent conducting oxide

In this study, electroless Pt films deposited on transparent conducting oxide (TCO)-coated substrates were prepared using a Pt-activated self-assembled monolayer (SAM) and employed as counter electrodes (CEs) in dye-sensitized solar cells (DSSCs). First, the mechanism for the formation of Pt-activated SAM on TCO-coated substrate was examined using X-ray photoelectron spectroscopy analyses. Second, the effects of the pH value and bath composition on the surface morphology and electrocatalytic activity were also investigated. After the optimization with the pH and composition of deposition bath, the Pt CE prepared by the optimized bath composition of electroless deposition (ELD) was found to have a lower Pt loading (15.91 μg cm− 2), a higher specific active surface area (209.71 m2 g− 1) and lower charge-transfer resistance (1.92 Ω·cm2) than the sputtered-Pt CE. Thus, the cell efficiency of the DSSC based on the ELD-Pt CE achieved 7.65%, which represented an increase of 12.33% when compared to the sputtered-Pt CE, while the Pt loading was also remarkably reduced (being 14.82% of that of the sputtered-Pt CE).