Study On Fabrication And Performance Of Flexible Counter Electrode In DSSC

The Counter-electrode （CE） of Dye sensitized solar cell （DSSC） is mainly used forthe collection of electrons and plays the role of catalyst, accelerating the speed of theelectronic exchange between the I₃^-/I^-and the CE. The traditional CE is commonly usedglass with a conductive film （such as ITO、SnO₂） as the substrate and coated withPlatinum （or Carbon, Gold, Nickel, etc） to decorate. But glass is crisp and fragile, whichlimits the application of DSSC. In this paper, the thesis has been designed with thepreparation of flexible CE. The polymer and metal have been used as alternationmaterials for CE substrates. A variety of low temperature plating processes wereadopted to fabricated Platinum CE on the plastic substrate, in order to seek the mostsuitable low temperature Platinizing for plastic substrate, the influence of differentplating processes on the photoelectric performance of plastic substrate based DSSCwere researched; A stainless steel sheet was treated by passivation or nickel-plating andthen used for fabricating platinum Counter-electrode. The influences of substratepassivation/nickel-plating and coated platinum on the conductivity, electronictransmission, corrosion resistance of CE, the influences of plating thickness andmorphology of substrate on the photoelectric performance and long-time stability ofDSSC were studied. The main results of this dissertation are listed as following:①The charge transfer resistance at the Counter-electrode/electrolyte interface（RCE） and the series resistance （RS） were all the lowest when the plastic Platinum CEwas fabricated by chemical deposition, the photoelectric conversion efficiency of thecorresponding cell was highest and the followed is screen printed. Effects ofElectrochemical deposition and spin-coated were not as good as chemical deposition.②The initial photoelectric performance of DSSC was improved when usednickel-plated stainless steel as CE substrate compared to un-nickel-plated stainless steel.In addition, the conversion efficiency and the fill factor of DSSC were the highest whenthe nickel-plating time was120minutes.③When using nickel-plated stainless steel as Counter-electrode substrate, thestability of cell was better than that of the un-nickel-plated stainless steel based cell, andwith nickel-plating time prolonged, the stability initially improved and then decreased.The optimum nickel-plating time was120minutes.④The corrosion resistance of stainless steel304in the iodine containing solution can be increased by acid treatment in16.7%HNO₃+2%HF+H₂O solution and thenpassivated in38%HNO₃+H₂O or7.5%HNO₃+4%K₂Cr₂O₇+H₂O solution; the DSSCemploying those passivaed STS304coated with thermal deposition Pt asCounter-electrode exhibited better photovoltaic performance compared with on the useof un-passivated STS304Counter-electrode. This result is attributed to the fact that thePt-coated passivated STS304counter-electrode simultaneously have lower chargetransfer resistances; When using passivated STS304, the stability of the DSSCimproved significantly.