Novel Counter Electrodes With Low Cost And High Performance For Dye-sensitized Solar Cells

The counter electrode is an important part of dye-sensitized solar cell （DSSC）. Not onlycan it accept the electron from the external circuit, but also catalyze the reaction of I3-reducing to I-in the electrolyte occurred on the surface of counter electrode. At present, theplatinum plated conductive glass is widely used as the counter electrode of DSSC, because ofits good catalytic activity and high conductivity. However, platinum is noble metal and highcost which hinders the commercialization of DSSC. Consequently, developing novel materialswith good catalytic activity and low cost for the counter electrode of DSSC are attracting anincreasing attention in recent years. This paper is dedicated to finding the new materialswhich are high catalytic activity and low cost to replace the platinum electrode.The first time to use the transition metal compounds MoS₂as catalytic layer of electrodematerial applied in the dye sensitized solar cell, and made into the composite materials withthe flake graphite and carbon black respectively coating on the FTO conductive glass. Thecyclic voltammetrys, tafel polarization curves, electrochemical impedance spectroscopys andother methods were used to analyze the electrocatalytic activity of single MoS₂electrode andMoS₂/C electrodes, eventually contrasted with sputtered-Pt electrode. The result showed thatthe electrocatalytic activity of MoS₂electrode was poor. When it composited with carbonmaterials, especially the carbon black, the electrocatalytic activity of composite electrode hasenhanced. However, there has a gap between the new novel electrodes and sputtered-Ptelectrode.The Pt/C electrocatalytic material of the field of fuel cells was introduced into the DSSCto replace Pt counter electrode, I used the simple chemical reduction method to prepare Pt/Ccounter electrode to assemble applications in DSSC. The influence of calcination temperature,content of Pt, fabrication method and additive to the catalytic activity of Pt/C electrodes wereexplored respectively. The results showed that when the calcination temperature of280°C,electrocatalytic activity was good which prepared by the direct mixing and simple chemicalreduction method, the overall photoelectric efficiency of DSSC composed with it is achievedover80%of the cells based on sputtered-Pt counter electrode. The P25nanoTiO2powder was proposed to add into the above Pt/C counter electrode to improve the adhesion between thePt/C catalyst layer and FTO substrate. The studies showed that added P25to the Pt/Ccomposite electrocatalytic material, reducing series impedance between the film and substrateand thus ultimately to further enhance the photoelectric conversion efficiency of DSSC.From the dispersion Pt modified the polyaniline electrode catalytic oxidation offormaldehyde, methanol and achieved the good activity, used Pt-PANI/FTO prepared byelectrochemical method as counter electrode of DSSC, analyzed its electrocatalytic activity.The result showed that the electrocatalytic activity of dispersed Pt modification polyanilineelectrode was good, the electron transfer impedance between the electrode and the electrolyteRctwas very low in result that the overall photoelectric efficiency of DSSC composed with itis achieved over75%of the DSSC based on the sputtered-Pt electrode.