Preparation And Researches Of The Counter Electrode For Dye-sensitized Solar Cells

Dye-sensitized solar cells(DSSCs)are photovoltaic devices with characteristics of their relatively high power conversion efficiency,environment friendly and facile fabrication process.The traditional counter electrode material of DSSCs is platinum,which is very expensive.In order to find a more suitable material to replace the platinum,it is a research hotspot to find low cost,high catalytic activity and well conductivity material.Recently,it is widely reported that some specific transition metal compounds exhibit good catalytic activity as counter electrodes for DSSCs alternatives to the platinum because of their similar electronic structures with platinum,such as mental nitrides,carbides,and chalcogens and so on.It is found that the transition metal selenium compounds with two-and three – elements transition metal have similar catalytic activity with platinum,and they are the most valuable electrode materials.Followings are our works:The NiSe2 material was produced by hydrothermal electrochemical deposition new method,then to test the conductivity,catalytic and power conversion efficiency of this material using in the DSSC as counter electrode.The experiment results show that the better characteristic of NiSe2 when the deposition time was 20 s,the bath temperature was 90℃,the pH value of the bath solution was 3,the ratio of Ni and Se was 0.5.Based on the former experiments,we compared the performance of NiSe2 made by hydrothermal electrochemical deposition(HED-NiSe2)method and electrochemical deposition(ED-Ni Se2)method.After detail experiment,we found that the former shows better electrochemistry performance.Then we fabricated NiSe2 as free-Pt CE for DSSCs,the HED-NiSe2 performs better catalytic ability and faster electron-transport in comparing counter electrodes,and higher photoelectric conversion efficiency.Above all,the hydrothermal electrochemical deposition method is an excellent way to produce the material of counter electrode.The ternary nickel–cobalt seleniums have been intensely investigated because of their higher electric conductivity and stability than binary cobalt seleniums and nickel seleniums.Cyclic voltammetry(CV)curves,Tafel plots and electrochemical impedance spectroscopy(EIS)have been measured to evaluate the good electro-catalytic activity and conductivity of the NiCoSe2 counter electrode.The DSSC by testing the current and time curves displayed a high conversion efficiency of 8.32%,which demonstrated the NiCoSe2 is an excellent material for DSSCs.