Preparation Of Counter Electrodes Based On Carbonaceous Materials And Their Applications In Dye-Sensitized Solar Cells

The unrestrained exploitation and uncontrolled use of non-renewable energy,such as coal and petroleum,lead to particularly serious energy shortage and environmental problems.Therefore,it has become highly urgent to investigate and develop renewable energy.Among them,solar cells have attracted much attention.As the third generation solar cells,dye-sensitized solar cells have the advantages of environment-friendly and low toxic energy,low cost,high photo-electric efficiency and simple preparation process,which are expected to realize the industrialized application.Counter electrode has important influence on the properties of the DSSC.Platinum is a traditional materials for counter electrode due to its high conductivity and catalytic properties.However,the high price and rare reserves restrict its large scale application.At present,carbonaceous materials have become a hot frontier in the field of counter electrode materials because of their merits of low cost,abundant reserves,good chemical stability and high conductivity.In this paper,three kinds of carbonaceous materials are focused to explore their corresponding characteristics as counter electrodes,and further investigate the performances of dye-sensitized solar cells.The main research contents are as follows:?1?Carbon paste materials.The carbon paste counter electrodes were prepared on FTO glass by the doctor-blading method and sintering at different temperature.The results show that as the temperature increases,the agglomerate morphology of the carbon paste gradually weakens,which almost disappears at around 400 ^oC,and the morphology begins to transform into a loose porous form.At the same time,both charge transfer resistance and Nernst diffusion resistance have been substantially reduced,and the efficiencies of the DSSCs based on these materials have been increased from 0.51%at 120 ^oC to 0.92%at 400 ^oC.The latter has a filling factor?0.57?similar to the DSSC based on platinum.The results indicate that the conductivity and catalytic activity of the carbon paste on the electrode are greatly improved with the increase of temperature.?2?PEDOT:PSS/carbon black materials.The mixure of PEDOT:PSS with different amount of carbon black particles was ground into a slurry,and cast onto FTO glass via the doctor-blading method to prepare counter electrode.The experimental results indicate that the photoelectric conversion efficiencies of PEDOT:PSS/C composite electrodes with 1%,5%and 10%carbon black doping are 1.53%,2.76%and 2.81%respectively,and the efficiency increases significantly with the increasing content of carbon black.In addition,the charge transfer resistance highly decreases,and it reaches 1/5 of the Pt electrode at 0.20??cm² as the content of the carbon black content is 10%.The addition of carbon black increases the surface roughness and the specific surface area of the PEDOT:PSS/C composite counter electrode,which enriches electrocatalytic active sites for redox I₃^-/I^-,and thus effectively improving the catalytic performance of counter electrodes.?3?Laser reduced graphene oxide materials.The reduced graphene oxide?rGO?counter electrode was prepared by direct laser writing via DVD driver using graphene oxide casting onto ITO substrate,and then assembled into a solar cell.The results demonstrate that the graphene oxide successfully was changed into rGO film with micro-stripes structure after laser-scribing.The multilayer-stack and porous morphology of rGO film increases the catalytic performance of electrodes,and its efficiency reaches at 2.07%.