Prepartion Of Co_xS_y Based Materials And Their Application For Dye-sensitized Solar Cells

Dye-sensitized solar cells?DSSCs?are promising photovoltaic devices,mainly because of their low cost and high efficiency.A standard DSSC has three main components: a dye-sensitized TiO2 photoanode,an iodide/triiodide?I3-/I-?redox electrolyte,and a counter electrode?C E?.The CE plays a key role in improving device performance by catalyzing reduction of the electrolyte.The conventional material for CEs is Pt,which has remarkably high conductivity and efficiently catalytic for the reduction of I3-to I-.However,large-scale commercial application of Pt-containing DSSCs is seriously hindered by the high cost and low abundance of Pt.Hence,much effort has been devoted to the development of alternative CE materials.Compared with other materials,cobalt sulfides are cheaper and more effective to improve the performance of DSSC with their excellent catalytic ability.However,owing to the ir nonconductive properties and complex synthesis precedure,it highly blocks the development of commerical DSSC.In this paper,we pepared efficient CoxSy CE materials with a simple and cheap synthesis process.To further solve the nonconductive problems of CoS materials,we design to combine the high-conductive carbon materials and the high-catalytic activated CoS materials to enhance the performance of DSSC.And the main content is as follows:We prepared CoS_x nanosphere grown on the FTO conducting glass by a simple one-step process and optimized the synthesis conditions.By applying the CoS_x materials to DSSC,the CoS_x materials displayed excellent catalytic activity for the reduction of I3-,which show a high ?Ep about 0.32 V and a peak current at 2.02 mA cm-2 compared with Pt??Ep = 0.34 V,peak current = 2.07 mA cm-2?.Besides,the exchange current density J0 of CoS_x is about 1.87 mA cm-2 which is close to Pt?J0 = 2.04 mA cm-2?.The results can be explanied to that the hollow CoS_x nanosphere is benefit for the diffusion of electrolyte meanwhile increase s the active sites to improve the catalytic activity with the high specific area of hollo w nanostructured CoS_x materials.Thus,with the hollow CoS_x nanosphere prepared by this paper,the DSSC shows a high battery efficiency about 9.07% which is as high as traditional Pt material?9.10%?.To further solve the nonconductive problems of CoS materials,we prepared Co_1-xS and nitrogen doped graphene composite materials namely Co_1-x S/N-RGO.By combining the the high-conductive carbon materials and the high-catalytic CoS materials,it can be high efficiently to enhance the performance of DSSC.Copmared with Co_1-xS/RGO,N-RGO and Pt materials,the Co_1-xS/N-RGO show the best catalytic performance and photovoltaic performance.The results can be attributed to that the composite materials have high conductive,catalytic activity and abundant active sites to improve the catalytic activity with the high specific area of 3D structured doping graphene composite materials.In conclusion,with the 3D Co_1-x S/N-RGO composite materials pepared by this paper,the DSSC show a high battery efficiency about 9.24% which higher than the traditional Pt material?9.10%?.