Preparation And Performance Of Counter Electrode For Dye-sensitized Solar Cells

As a novel cell in the energy field, Dye-sensitized solar cell (DSSC) has theadvantages including high theoretical conversion efficiency, simple processing, lowcost, and environment friendly raw materials. DSSC has gradually become one of theresearch hotspots in the world. Counter electrode is an important part of DSSC, whichhas been paid more attention to in recent years. Because of the high catalytic activityand relatively low overpotential to I-/I-3redox reaction, platinum became the widelyused as DSSC counter electrode material. As a novel metal, the high cost of platinumcounter electrode limited the large area production and application of DSSC. As aresult, researchers attempt to obtain the cost effective DSSC with high efficiency bythe way of changing the preparation method and the substrate, or preparing the newmaterial.In this paper, Pt/ITO counter electrode and Pt-Ru/ITO alloy counter electrodewas prepared applying electrochemical deposition. Through optimizing technologicalconditions, the catalysts nanoparticles with higher catalytic activity were formed onthe ITO conductive glass. By various characterization methodes, the influence ofpreparation process on the surface morphology and electrochemical performance ofelectrodes was studied, and photoelectric properties of the assembled single DSSCwas measured. The result showed that, when proper temperature, deposition time,current density and Pt/Ru mole ratio in the plating solution were applied, the catalystparticles with proper size were distributed uniformly on the surface of electrodes;these electrodes performed the better electrochemical activity than Pt sheet.Compared with electrodeposited Pt/ITO electrode, the performance of Pt-Ru/ITOelectrode was more stable.Ni-P alloy film was formed on the ITO glass substrate via chemical depositionmethod, and then Pt nanoparticles were electrodeposited on the surface of alloy film,finally, Pt/NiP/ITO electrode was obtained. The preparation process was researched;the characterization of surface morphology, electrochemical performance of counterelectrodes and photoelectric properties of DSSC based on Pt/NiP/ITO counterelectrode was carried out. The result showed, modified with Ni-P alloy film, theconductivity and light reflection ability of ITO substrate were effectively increased,consequently the comprehensive internal resistance and light utilization ratio of DSSCwere improved separately, and finally the comprehensive efficiency of DSSC wasincreased by11%. Thermal decomposition was also applied to prepare platinum counter electrodefor DSSC, and the influence of preparation process on the surface morphology andelectrochemical performance of Pt/ITO electrode was researched. By optimizing theplatinum loading, adhesive type and usage, the Pt/ITO electrode with stableperformance was made. A series of measurement methods were applied tocharacterize the performance of Pt/ITO electrode. The result showed that when0.06mg/mL CMC was used as adhesive, the as-prepared electrode performed bettercatalytic activity with a low Pt loading of0.235mg/cm2. The conversion efficiencyof assembled DSSC with Pt/ITO as counter electrode approached to that with Pt sheetas counter electrode.