Preparation And Study Of High Efficient And Low Cost Counter Electrode Of Dsscs Based On Carbon/Sulfide Composite Nanomaterials

Dye-sensitized solar cells（DSSCs）are an attractive energy conversion technology,generating extensive interest because of their low cost and the possibility of mechanical flexibility.As an important component of DSSCs,the counter electrodes（CEs）play a key role in rapidly collecting electrons from the external circuit and catalyzing the reduction of I I3-.Platinum（Pt）has been widely used as CEs in DSSCs because of its chemical durability and superior electrocatalytic ability for the redox reaction of I-/I3-.However,Pt is very expensive and rare,which limits the large-scale commercial production of DSSCs.Therefore,it is particularly important to find high-cost and low-cost Pt alternatives for counter electrode materials.The main work of this paper is as follows:（1）Porous graphene-doped Cu In S2/carbon（p-GN@CuInS₂/C）composite nanofibers were fabricated via electrospinning,in situ synthesis,and carbonization.A polyacrylonitrile（PAN）solution containing graphene oxide nanosheet,copper dichloride（CuCl2）,indium trichloride（InCl3）,and thiourea in a mixed solvent of N,N-dimethylformamide/trichloromethane（DMF/CF）was used as the precursor solution for electrospinning.DSSC assembled using the pGN@CuInS₂/C nanofibers as CE delivered photoconversion efficiency（η）of 7.23%,which was higher than the efficiencies of DSSCs assembled using the samples without graphene（6.48%）and with the CuInS₂/C nanofibers（5.45%）.It was also much higher than that of the DSSC with a Pt CE（6.34%）.（2）In this work,carbonized-cellulose nanowhiskers/FeS₂@reduced graphene oxide（CCW/FeS₂@RGO）composite was synthesized through a facial hydrothermal method with CNWs as the bio-template and high-temperature carbonization.C-CW/FeS₂@RGO composite is as the CE of DSSC.From cyclic voltammetry,impedance spectroscopy,and Tafel polarization measurements,the electrocatalytic activity of C-CW/Fe S2@RGO CE for reduction of triiodideions is higher than that of Pt CE.DSSC assembled C-CW/Fe S2@RGO CE delivered a higher η of7.05% than that of Pt CE（η = 6.24%）.The excellent photoelectric performance of the CCW/FeS₂@RGO CE makes it expected to replace the expensive Pt electrode in DSSCs.