Study On The Counterelectrode Used In Dye-sensitized Solar Cell

Dye-sensitized solar cell (DSSC) is a new type of photoelectric chemical solar cell with simple preparation procedure, low cost, stable photo-to-electric performance and friendly environment action, which make it a good alternative of photo-to-electric devices, bring a large range of attention of the researchers in the world and is considered a landmark in the research of solar cell, ever since it firstly came into being. As an important part of DSSC, the counterelectrode is gradually attracting more interest from the whole world. Pt is widely used in DSSC as the counterelectrode because of its good and active catalysis as well as its stability in the electrolyte. However, with the problem of high cost, Pt counterelectrode goes against its industrialization. In this paper, the Pt counterelectrode as well as Pt-Ru alloy counterelectrode of DSSC was prepared by electro-deposition. The preparation technics were optimized, and the electrochemical properties of the electrode were tested via several methods.A concentration of 1.931×10-3 mol/L H2PtCl6 for preparing Pt electrode was made as a precursor; 0.5 g (NH4)2HPO4, and 1.5 g Na2HPO4 were added in succession. The morphology and electrochemical property of Pt counterelectrodes were tested by AFM (Atom Force Microscope) and CV (Cyclic Voltammetry). We concluded that the morphology and electrochemical property were dependent on different Pt quality and different current density. It showed that a plating time of 90 s and current density of 15 mA/cm2 were the proper conditions to get a Pt quality of 3.733×10-4 g/cm2, with good morphology and electrochemical property.H2PtCl6 and RuCl3 solution with different Pt-Ru weight ratio was made as a precursor, according to the best combination above. The effect of different Pt-Ru atomic ratio both in the electrolyte and on the electrode to the electrochemical properties was studied by EDS (Energy Dispersive Spectrum),SEM (Scanning Electron Microscope) and CV. The investigation showed that a best Pt-Ru counterelectrode was achieved when the atomic ratio of Pt-Ru in the electrolyte was 1:0.918, and 1:0.15 on the electrode.We found that the property of Pt-Ru alloy counterelectrode did not change as much as the increase of Ru, after we compared the Pt counterelectrode and the Pt-Ru counterelectrode. About 13 atomic% Pt was as a result saved by using Ru to take the place of Pt. Besides, the oxygen reductive peak value of Pt-Ru alloy counterelectrode decreased greatly, with proof that the property of the electrode was improved a lot by using Ru, which made the electrode good performance of CO-tolerance, and improved the property of Pt electrode. The cost of DSSC was also lowered down to bring a bright future of industrialization.